Article: 223225 of rec.radio.amateur.antenna From: chuck Subject: Re: VSWR AND AUTOMATIC TUNING References: <1144360350.476305.270240@u72g2000cwu.googlegroups.com> Message-ID: Date: Fri, 07 Apr 2006 00:05:02 GMT Dave wrote: > Big Nose wrote: > >> If a transceiver has an in built automatic antenna tuning and matching >> unit, is there any point in measuring the VSWR as a way of ascertaining >> its performance? > > > NOPE! The VSWR in the line = The VSWR in the line = The VSWR in the > line = The VSWR in the line. The internal tuner does absolutely nothing > [NOTHING] to the VSWR in the line. > > The internal tuner will make the radio 'happy' within it's tuning range, > but it does NOTHING about the VSWR in the line! > > >> >> Obviously this would be measured with a thru line meter which would be >> placed in the feeder system. However, I have been thinking and it >> would appear that the tuning and matching unit would become part of the >> antennas impedance (its late and I hope that makes sense). >> >> The reason I ask is because I am trying to find out how well certain >> transceivers will perform with antennas which are designed for >> different systems. >> > To elaborate just a bit on Dave's comment, remember that the VSWR is determined only by the LOAD (antenna) impedance and the LINE characteristic impedance. The source (transmitter) impedance does not enter into the determination of VSWR. One way tuners are tested is with dummy loads of various resistances (and/or reactances). QST published some articles on this a few years ago. Good luck. Chuck, NT3G Article: 223226 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1239aaafdv8fa49@corp.supernews.com> <1239epjqpmci573@corp.supernews.com> Subject: Re: Must 300 ohm feedline be kept completely clear of contact w anything? Message-ID: Date: Thu, 6 Apr 2006 17:14:07 -0700 "Thomas anonymous" wrote in message news:Thomas.anonymous.25v2z9@news.radiobanter.com... > > Well, that's what you call a definitive answer, hi. I live on the > Canadian Wet Coast, near Vancouver --- you could say moisture is > sometimes a factor around here ... > :) > > Thx and 73 from Canada > > > -- > Thomas anonymous Thomas, Belden made a product called "Shielded Perm-ohm" 300 ohm shielded twin lead. It apparently still exists, but not with that name. Go to http://www.fairradio.com/wirean.htm and search for it. The product is now called "City Color," according to that web page. Some years ago I used it to pass perfect TV signals through a 15-foot conduit out of my attic . (An earlier attempt with regular twinlead was a disaster.) I believe the shielded twin lead has slightly less loss than coax. Article: 223227 of rec.radio.amateur.antenna From: "amdx" References: <74ac6$44347c7f$45011502$11431@KNOLOGY.NET> <1144326826.706548.100400@g10g2000cwb.googlegroups.com> <123auob9ii13c8c@corp.supernews.com> Subject: Re: Transforner Theory Date: Thu, 6 Apr 2006 19:44:55 -0500 Message-ID: <785a6$4435b605$45011502$12759@KNOLOGY.NET> "Roy Lewallen" wrote in message news:123auob9ii13c8c@corp.supernews.com... > amdx wrote: > > . . . > > My questions still stand, > > Question 1 > > How many gausse is used to measure permeability and set AL? > > Essentially zero. Ok, So I'll use the figure of 1 gausse as where permeability is measured and >from there I can assume the inductance increases 40 percent at 2000 gausse for the toroid specified on the Magnetics webpage. The only info I have is from Ferroxcube Soft Ferrites and accessories 2000 data book, and it simply says "The initial permeabilty is measured------ at a very low field strength." > > Question 2. > > Can anyone take a stab at how many gausse in a typical FT140-43 toroid > > with 8 turns on the secondary, and 34 or 35 turns on the primary used on a > > flag antenna with a low level signal. > > I won't bother to calculate it because the change in permeability would > be so small you wouldn't be able to measure it. This is a non-problem; > you're wasting your time worrying about it. I'm not worrying, just curious, since I've been using a large potcore to deliver microwatts that at one time I used at near a kilowatt. Just wondered if we were losing some low frequency response because of a change in permeability. It seems as though the permeabilty measurement is made nearer the power levels of our receive antenna signals. > > > On the second question the material can be modified to reflect the material > > and turns as needed. > > If your circuit is sensitive to a change in a few parts per million of > permeability, it has serious problems. The permeability will change > several orders of magnitude more than that with modest changes in > temperature. > > Roy Lewallen, W7EL Thanks Roy, I appreciate the discussion and information. Mike Article: 223228 of rec.radio.amateur.antenna From: Allison-nospam@nouce.bellatlantic.net Subject: Re: How get RF through a sealed window? Message-ID: References: Date: Fri, 07 Apr 2006 02:01:09 GMT On 6 Apr 2006 11:06:22 -0500, mcalhoun@ksu.edu wrote: >I gave a presentation on "How Ham Radio Can Help You in an Emergency" >to 70 Emergency Management types last week, and the windows in the >building which hosted the meeting were NOT open-able (so I "made do" >with an inside VHF antenna and didn't even try to demonstrate HF). > >But in emergency/expedient situations, it would be really handy if one >could pass at HF, say, 100 watts of RF energy through a window (I >visualize some foil strips and an inductor or two to "tune out" the >capacitance) to an external antenna. > >I've been told that the April, 1989, issue of Ham Radio magazine carried >an article "Easy antenna access for urban apartment dwellers" (for 15 >meters) by Bryan Bergeron, NU1N, starting on page 18. > >I'd sure like to read that article; can anyone send me a copy? Real simple answer, you can't. There are few things you can do that do not involve drilling, cutting or blasting. The problem is most modern buildings use thick or double pane glass and possibly low E all of which make the common tricks work very poorly. also if you more than one maybe two floors floor up the outside of the glass will be inaccessable If your creative and really look you might find an HVAC duct you can pass coax through. Allison Article: 223229 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Thu, 6 Apr 2006 23:22:01 -0400 W8JI and other unbelievers that antenna and loading coils can not be expressed in electrical degrees, can find another example in ON4UN's Low Band DXing book, 4th edition, page 9-47, Fig 9-58, showing loaded vertical with mast being 40 deg. 59.6 ft. long, loading coil of 144 uH taking (replacing radiator of) 40 deg and whip of 10 deg and 14.9 ft long, for overall 90 deg electrical and quarter wave resonant system. Soooo, to anyone outside of "equal current worshippers" it is obvious that coil is replacing 40 deg worth of radiator and it would drop equivalent amount of current across the coil that corresponds to the length of radiator that coil replaces, because rest of the "straight" radiator FORCES IT TO DO - because of standing wave and current. Such a heresy! Theeere is your sign! Yuri, K3BU/m Article: 223230 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: Given my restrictions, how can I improve my HF antenna? Date: Fri, 07 Apr 2006 05:39:08 -0000 Message-ID: <123bunsakbdii6f@corp.supernews.com> References: In article , Thomas anonymous wrote: >I'm renting a basement suite and have an Icom 706mkII & MFJ-949E antenna >tuner, and I need a better HF antenna arrangement than I already have >(without going to a tower, hi). I would like to run a balanced >feedline from the tuner to the feedpoint but the feedline has to go >from my shack to where the feedpoint is, and that involves crossing a >cement path --- in other words, because the feedline has to lie on top >of cement it can't really be anything other than coax. You could make up a section of shielded balanced line, to get the feed across the cement without having it couple messily into the ground. A shielded balanced line can be made from two equal-length runs of coax cable. RG-6 would work; aluminum-jacketed cable-TV hardline might be even better from an electrical standpoint although its rigidity might be inconvenient. Connect the shields/braids of the two sections of coax together at each end, use the center conductors to carry the signal, and fasten the two coaxes together in some convenient fashion (an occasional nylon wire-tie would do, I believe). The impedance of such a line will be twice that of the individual pieces of coax - i.e. 150 ohms if you use RG-6. No need to worry about matching it to the rest of the balanced feedline. You can use 300 or 450 or 600-ohm (nominal) balanced line where convenient, to keep the losses as low as practical, and this 150-ohm shielded balanced pair where necessary. The losses should be acceptable, and will certainly be less than if you plumbed the whole distance with 50- or 75-ohm coax. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! Article: 223231 of rec.radio.amateur.antenna Subject: Re: How get RF through a sealed window? From: "Allan R. Batteiger" References: Message-ID: Date: Fri, 07 Apr 2006 05:45:28 GMT mcalhoun@ksu.edu wrote in news:e13e9u$q3u@unix1.cc.ksu.edu: > I gave a presentation on "How Ham Radio Can Help You in an Emergency" > to 70 Emergency Management types last week, and the windows in the > building which hosted the meeting were NOT open-able (so I "made do" > with an inside VHF antenna and didn't even try to demonstrate HF). > > But in emergency/expedient situations, it would be really handy if one > could pass at HF, say, 100 watts of RF energy through a window (I > visualize some foil strips and an inductor or two to "tune out" the > capacitance) to an external antenna. > > I've been told that the April, 1989, issue of Ham Radio magazine carried > an article "Easy antenna access for urban apartment dwellers" (for 15 > meters) by Bryan Bergeron, NU1N, starting on page 18. > > I'd sure like to read that article; can anyone send me a copy? I do not have the article but one solution that was proposed and tried worked great. Use tinfoin and rubber glue, cut the tin foil to fit the glass. Apply rubber glue to hold the foil to each side of the glass, Thickness of teh glass is not important. In my case I used the metal frame of the glass to carry the gound signal through the window frame. I then used an antenna tuner to adjust out the capacitor I just created. Worked great, no drilling no running coax in and out so I can close the window etc. Allan WB5QNG Article: 223232 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Thu, 06 Apr 2006 23:47:53 -0700 Message-ID: <123c2oranvatgf4@corp.supernews.com> References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> Of course loading coils can be expressed in electrical degrees. But extrapolating this to mean that a loading coil has the same properties as an antenna with the same number of "degrees" has no justification. Yuri's theory was shown to be false not only by many of the good technical arguments given here in this thread, but also by a careful measurement I made over a year ago. I built a 33 foot high vertical and loaded it at the bottom with a toroidal inductor to resonate it at 3.8 MHz. The coil "replaced" 33.4 electrical degrees of antenna. Yuri's theory predicts that the current at the top of the inductor should be 16.5% less than that at the bottom, with a phase shift of 33.4 degrees. What I measured was a current drop of 5.4% and no measurable phase shift across the inductor. Both the description of the setup and the detailed results were posted on this newsgroup on Nov. 11, 2003, with the subject title "Re: Current in antenna loading coils controversy - new measurement". Anyone can find those postings with groups.google.com. Yuri's response, also on Nov. 11, 2003 was to complain about my methodology, declare that he was still right, and state "I will measure things myself, try to verify previous measurements and then come up with conclusions and 'theory'." On Nov. 12, 2003, he posted: "I will be making snap-on current probe, which will make it easier to slide along the element and observe the current without the disturbance to the antenna and will be a bit different over the thermocouple meters. Just need a bit more time." Well, it's been over a year now, and all I've seen is the same unsupported theory with no evidence to contradict the contrary evidence which has been presented. When a belief stays fixed in spite of both contradictory solid theory and measurements, it fits into the category of religion, not science. So it's appropriate that Yuri speaks in terms of an explanation being a "heresy". What's next, "good" and "evil" theories? Roy Lewallen, W7EL Yuri Blanarovich wrote: > W8JI and other unbelievers that antenna and loading coils can not be > expressed in electrical degrees, can find another example in ON4UN's Low > Band DXing book, 4th edition, page 9-47, Fig 9-58, showing loaded vertical > with mast being 40 deg. 59.6 ft. long, loading coil of 144 uH taking > (replacing radiator of) 40 deg and whip of 10 deg and 14.9 ft long, for > overall 90 deg electrical and quarter wave resonant system. > Soooo, to anyone outside of "equal current worshippers" it is obvious that > coil is replacing 40 deg worth of radiator and it would drop equivalent > amount of current across the coil that corresponds to the length of radiator > that coil replaces, because rest of the "straight" radiator FORCES IT TO > DO - because of standing wave and current. > > Such a heresy! > Theeere is your sign! > > Yuri, K3BU/m > > Article: 223233 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Thu, 06 Apr 2006 23:51:33 -0700 Message-ID: <123c2vmeq69bv41@corp.supernews.com> References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144391840.390341.262170@e56g2000cwe.googlegroups.com> K7ITM wrote: > Another 'speriment occured to me, for those who think the coil current > MUST be different at the two ends by the amount corresponding to the > antenna section it replaces: try making the antenna diameter large > compared with the coil diameter, say two to four times the coil > diameter, while maintaining the same lengths, and see what happens. I > suppose you'll have to adjust the inductance of the coil, but keep its > diameter and length the same. If the current at the ends of the coil > remains nominally the same as with a thin antenna, then I'll say you're > onto something. If on the other hand, the current becomes much more > similar at the two ends of the coil, that will be evidence of a > different effect--in fact the effect that I expect is actually > accounting for the difference. > > Perhaps someone would like to try that in NEC2 or NEC4 and share the > results, if nobody is actually up to building the antenna and measuring > things. I'm afraid that the proponents of the alternative theories aren't subject to either modeling or measurement results. There's already ample theoretical, modeling, and measurement evidence to show that the theory is faulty; further efforts would be a waste of time. Roy Lewallen, W7EL Article: 223234 of rec.radio.amateur.antenna From: N7ZZT - Eric Oyen Subject: Re: Balloon lifted wire antenna? References: <220320061901558586%artie.m@gNOSPAMmail.com> Message-ID: Date: Fri, 07 Apr 2006 03:34:32 -0700 Ralph Mowery wrote: > > I see that you have reached your limit. Check the data and repost with > the correct ammount of electrons, protrons and neutrons. Ralph, check the periodic table again. helium is a NOBLE gas (it exists on the far right hand column of the periodic table because of its non-reactiveness). Helium is Element 2. atomic weight: 4.002602 Number of Protons/Electrons: 2 Number of Neutrons: 2 information from this link < http://www.webelements.com/webelements/elements/text/He/key.html > is as follows: "Helium is one of the so-called noble gases. Helium gas is unreactive, colourless, and odourless. Helium is available in pressurised tanks. Elemental helium is a colourless odourless monoatomic gas. Helium is the second most abundant element in the universe after hydrogen. a particles are doubly ionised helium atoms, He2+. Helium is used in lighter than air balloons and while heavier than hydrogen, is far safer since helium does not burn. Speaking after breathing an atmosphere rich in helium results in a squeaky voice (don't try it!). Isolation Here is a brief summary of the isolation of helium. There is very little helium on earth as nearly all present during and immediately after the earth's formation has long since been lost as it is so light. Just about all the helium remaining on the planet is the result of radioactive decay. While there is some helium in the atmosphere, currently its isolation from that source by liquefaction and separation of air is not normally economic. This is bacause it is easier, and cheaper, to isolate the gas from certain natural gases. Concentrations of helium in natural gas in the USA are as high as 7% and other good sources include natural gas from some sources in Poland. It is isolable from these gases by liquefaction and separation of from the natural gas. This would not normally be carried out in the laboratory and helium is available commercially in cylinders under pressure." note the part where it says: "There is very little helium on earth as nearly all present during and immediately after the earth's formation has long since been lost as it is so light. Just about all the helium remaining on the planet is the result of radioactive decay." would you care to explain that????? conversely, Hydrogen is: Element 1 atomic weight: 1.00794 Number of Protons/Electrons: 1 Number of Neutrons: 0 hydrogen is also known to have *at least* 5 known isotopes (all unstable and all prone to radioactive decay). lastly, as for your personal dig at my signature, me thinks thou doth protest too much! -- DE N7ZZT Eric Oyen Phoenix, Arizona e-mail: n7zzt(at)hotmail(dot)com the difference between intelligence and stupidity is that intelligence has its limits. Article: 223235 of rec.radio.amateur.antenna From: N7ZZT - Eric Oyen Subject: Re: Balloon lifted wire antenna? References: <220320061901558586%artie.m@gNOSPAMmail.com> Message-ID: Date: Fri, 07 Apr 2006 03:41:51 -0700 jawod wrote: > last time I checked Helium has 2 protons and 2 electrons. I think the > previous poster implied that hydrogen exists as molecular hydrogen: H2, > as opposed to He that is mono-atomic. there was no reference to diatomic structures that I could discern. :( the problem with hydrogen is that it likes to either react with elements that are stable in diatomic form (such as Oxygen) or other elements that may have an excess of electron valence values (free electrons). Being that Hydrogen is a proton with an electron in orbit, the + charge of the proton will naturally tend to repel other elements of an equal charge, including itself. > > However, you have the better point: Hydrogen spells danger. Hydrogen, > Hindenburg,...If being a survivor means being a pansy...cool. the one advantage of Hydrogen is that it is very easy to produce planet side (add a little electricity, 2 probes of the same metal and enough water and there you go). Helium is rather harder to get here on earth. because of the processes involved, it tends to be pricey. -- DE N7ZZT Eric Oyen Phoenix, Arizona e-mail: n7zzt(at)hotmail(dot)com the difference between intelligence and stupidity is that intelligence has its limits. Article: 223236 of rec.radio.amateur.antenna From: N7ZZT - Eric Oyen Subject: Re: Balloon lifted wire antenna? References: <220320061901558586%artie.m@gNOSPAMmail.com> <1143475830.028569.213520@i40g2000cwc.googlegroups.com> Message-ID: Date: Fri, 07 Apr 2006 03:54:19 -0700 AC7PN wrote: > It is not the size of the atom that is relevant here. The important > thing is the size of the molecule. Helium is a one atom molecule while > Hydrogen is a two atom molecule. A single atom is much smaller than a > two atom molecule. Hence helium being the only single atom molecule in > existence, it is the king of jail break being able to slip through the > bars of any plastic prision cell. > > Bob Brunius > Orcas Island, WA > AC7PN ok, the original poster did not clarify as to which isotope of hydrogen was being used. H2 is a stable isotope (and yeah, I do stand corrected on that point). Still, the energies required to get 2 protons and 2 electrons to get along are fairly high. Hydrogen (H not 1 or 2 or bloody 3...) is very small (smaller than helium) and will tend to slip through most materials (except for possibly the extremely dense materials such as Polonium). perhaps in the future, we should be a bit more concise about things like this..... now I know that diatomic hydrogen is fairly common in nature (as in H2O, CH2 and a few others). I would have to ask a question of some folks over at ASU to see what they use for high atmosphere balloons. -- DE N7ZZT Eric Oyen Phoenix, Arizona e-mail: n7zzt(at)hotmail(dot)com the difference between intelligence and stupidity is that intelligence has its limits. Article: 223237 of rec.radio.amateur.antenna From: "Brian Murrey" References: Subject: Re: How get RF through a sealed window? Message-ID: Date: Fri, 07 Apr 2006 12:40:12 GMT Perhaps. In an emergency situation though, you do what you need to do and try not to let the regulations keep you from saving lives and/or property..while still keeping the regs in mind. When I use my portable mag loop for 20 and 40, from my hotel room, I try to place it outside my room...but that hasn't always been possible. At my low power I would have to guess the RF I'm bathing in should only be slightly more harmful than the X rays leaking out of my cheap "Made in Turdistan" TV set. I certainly wouldn't attempt using this setup with much more than a few watts of power. As for my attic dipoles, I have never tried to measure the exposure level in my home. I'll check in to that..but again, at 5w or less it can't be too dangerous. 73 -- ========================================= Radio Amateurs - Fill your junk box, from my junkbox! http://www.hamradparts.com 73 de KB9BVN ========================================= wrote in message news:e13sq1$fev@unix1.cc.ksu.edu... > >You'd have better luck with HF than VHF or UHF making it through any solid > >object. I have used a homebrew mag loop in a hotel room on several > >ocassions with some luck..on 20 and 40. > > Even in an emergency situation, I just don't think it would be a good idea > to string some kind of an antenna above the heads of shelterees and then > start soaking them with RF, especially depending on the HF frequency in > use. In fact, I suspect the FCC's RF-exposure regulations would frown on > one doing so! > > -- > --Myron A. Calhoun. > Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge > PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 > NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) Article: 223238 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> Message-ID: Date: Fri, 07 Apr 2006 12:59:37 GMT w8ji@akorn.net wrote: > A pure inductance would have no current difference at each end. Hard to prove by measurements since a pure inductance doesn't exist in reality. It's like saying there's no loss in a lossless transmission line which is true by definition. > One way to prove the coil does not replace missing length is to simply > move the coil to a new location in a fixed height antenna. If the coil > looked like 40 degrees, it would resonate the antenna no matter where > it was installed. The coil occupies a different number of degrees depending upon its location in the standing wave environment. That's why the resonant frequency of a bugcatcher system increases as the coil is moved up from the base. In a one wavelength standing wave system, if the coil is installed at a node, the currents at each end of the coil will be ~180 out of phase, i.e. the two currenets *appear* to be flowing in opposite directions at the same time. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223239 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144391840.390341.262170@e56g2000cwe.googlegroups.com> Message-ID: Date: Fri, 07 Apr 2006 13:03:24 GMT K7ITM wrote: > Another 'speriment occured to me, for those who think the coil current > MUST be different at the two ends by the amount corresponding to the > antenna section it replaces: To the best of my knowledge, nobody believes that. The coil is much more efficient at the loading function than is the straight wire from which it is made. That's why inductive loading is more efficient than fractal antennas or other types of linear loading. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223240 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Fri, 7 Apr 2006 09:24:28 -0400 wrote in message news:1144385028.313255.108730@u72g2000cwu.googlegroups.com... > > Yuri Blanarovich wrote: >> W8JI and other unbelievers that antenna and loading coils can not be >> expressed in electrical degrees, can find another example in ON4UN's Low >> Band DXing book, 4th edition, page 9-47, Fig 9-58, showing loaded >> vertical >> with mast being 40 deg. 59.6 ft. long, loading coil of 144 uH taking >> (replacing radiator of) 40 deg and whip of 10 deg and 14.9 ft long, for >> overall 90 deg electrical and quarter wave resonant system. >> Soooo, to anyone outside of "equal current worshippers" it is obvious >> that >> coil is replacing 40 deg worth of radiator and it would drop equivalent >> amount of current across the coil that corresponds to the length of >> radiator >> that coil replaces, because rest of the "straight" radiator FORCES IT TO >> DO - because of standing wave and current. > > > That is not correct Yuri. > > Anything from a pure inductance to a very poor distributed inductor > (like a linear loading or stub) can be used and all would have > different characteristics. "Pure inductance" - get me one, never subject of discussion here, about real antennas and real loading coils! > A pure inductance would have no current difference at each end. A good > compact inductor would have negligible current difference at each end, > only a long straight wire would act like the "missing antenna". More BS, insisting on non-reality. > One way to prove the coil does not replace missing length is to simply > move the coil to a new location in a fixed height antenna. If the coil > looked like 40 degrees, it would resonate the antenna no matter where > it was installed. WRONG, read below, it's the required inductance/impedance and fixed "missing" degrees that need replacement. > 73 Tom > Another big WRONGO Tom! As we go deeper into the discussion and "arguments" from "unbelievers" and thanks to NM5K posting, about how fixed coil acts different, replaces different amount of degrees, it hit me that the reason is the impedance presented by the antenna (the straight part) radiator at the coil insertion point. Using just as example, radiator having 90 degrees at the resonance, with 50 degrees of whip and coil "replacing" 40 degrees in the said example >from the book. You agree that impedance along the radiator changes, being low at the bottom, around tens of ohms, to being high at the top, around thousands of ohms. Now you place the loading coil along the radiator, one extreme being at the bottom, low impedance point - we know in order to maintain the resonance of say 13 ft high (long) radiator (90 electrical degrees at RESONANCE) the coil has a fewer turns, it's impedance is lower (as required by the lower impedance at the bottom end of the antenna), and current drop would relatively be small as W7EL proved and everybody knows. Now you move that coil say half way up the must, to higher impedance point at the antenna, and that coil now, in order to maintain the "match" has to have higher impedance, more turns and will exhibit MORE current drop across it, while replacing THE SAME NUMBER OF "missing" DEGREES AT THE RADIATOR. Assuming that our goal is to stay with the same physical length of the whip (which we do) and maintaining 90 degrees of resonant radiator. So the radiator stays 50 degrees ()+50, 10+40, 20+30, 30+20, 40 + 10) long and coil replaces the same "missing" 40 degrees. Same if you move the coil higher, higher antenna impedance point, more turns (inductance) required, more current drop exhibited, coil "replacing" THE SAME NUMBER OF 40 DEGREES. It needs more turns, but again, the coil's behavior is dictated by the impedance of the RADIATOR (standing waves) at the insertion point, dictating the inductance, number of turns of the coil in order to maintain the number of degrees, in order to maintain the resonance (90 degrees) of the radiator. In order to "overturn" this "Yuri's Theory" you would have to deny that resonant antenna has varying current across its radiator (wire) - to deny that current drops from the base to the tip. You would have to deny that coil in the RF circuit has varying impedance dependant on the number of turns and inductance and frequency. Deny that in order to maintain the resonant frequency of shortened radiator of the same physical length, you need to use coils of varying amount of turns depending on its insertion point along the radiator (less on the bottom, more closer to the top). That behavior of the coil is "FORCED" by the remaining "wires" in the radiator, in standing wave environment as Cecil is trying to get through with help of Kraus and others. So if the antenna is 50 degrees long and we want to maintain the resonance, the coil will replace (has to) the same 40 degrees regardless where it is placed, but its inductance and impedance will vary, depending on the impedance of the insertion point at the radiator. (Makes also sense - more turns - more current drop, RF choke effect. We are still talking RF current in standing wave antenna, not DC.) So the drop of RF current across the coil, depending on its position in the resonant quarter wave radiator can be from little at the base, to significant closer to the top, dependent on the position, insertion point, impedance of the radiator. This is much more significant cause of current drop across the coil that any "radiation or capacitance to the environment" (Tom's trying to "twist out of it") as is demonstrated by our arguments. So if we look at the fixed length of radiator and try to bring it to resonance with coils, placed at different locations along the radiator, we are replacing the SAME amount of electrical degrees, but depending on the required impedance, then the number of turns, or inductance has to be adjusted to conform. That jives what you and everybody knows and keep saying. So it is not the fixed inductance, (missing) length of wire in the coil, or same number of turns that replaces degrees of "missing" radiator, but the REQUIRED INDUCTANCE/IMPEDANCE and corresponding number of turns. I hope this makes it little bit more clear and shuts down another WRONGOOO that keeps popping up. Just measure it, stick it (properly defined) in EZNEC - IT IS ALL THERE, for everyone to see. So then if the standing wave causes drop of the RF current across the solid wire of the antenna, it also causes the drop of current across the loading coil, proportional to the amount of electrical degrees of radiator that coil "replaces", magnitude being dependent on the impedance and inductance required by the insertion point impedance along the radiator. (Almost sounds like "Yuri's Law" :-) I would like to thank NM5K for bringing it up and making me to understand what the "problem" and proof is. It made me realize what role impedance of the inductor plays in the STANDING WAVE antenna/circuit. Sooo! The coil can and have RF current variation, drop across it, just like piece of wire can, when in standing wave (antenna) environment. It is the major cause and not the whatever capacitance etc. You wanna call it K3BU's theory, I would be honored, but I do not claim any "ownership", many others before me showed that, directly or indirectly, including John Kraus, W8JK. I promise to do that article and series of experiments showing close correlation between measurements and proper modeling in EZNEC, just give me couple of weeks. I hope it will show and educate those willing to open their minds, and those "flat Earthers" can do what they choose to (look silly). I hope I made it more clear. I don't know how else I (we) can get it through! Soooo, but, but, but.... what? Yuri Blanarovich, K3BU.us I apologize to technical language purists for any clumsy wordiness' I may be guilty of. Article: 223241 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Message-ID: Date: Fri, 07 Apr 2006 13:44:19 GMT Roy Lewallen wrote: > Of course loading coils can be expressed in electrical degrees. But > extrapolating this to mean that a loading coil has the same properties > as an antenna with the same number of "degrees" has no justification. I haven't heard anybody make that assertion in years. Coils occupy whatever number of degrees that they occupy. The technical fact is that standing wave current phase cannot be used as the method of measuring the number of degrees. The graphic at http://www.travstnd.GIF shows why. The standing wave current phase is unchanging unless the monopole length goes over 1/4WL. > What I measured was a current drop of 5.4% and no measurable phase shift > across the inductor. But Roy, you used standing wave current phase to try to measure the phase shift across the inductor. The standing wave current phase is known to be unchanging in a wire. Why would you expect it to change through a coil? As Gene Fuller says, the only phase information in the standing wave current is in the magnitude measurement. If the magnitude changed by 5.4%, the phase shift was roughly arc-cos(1 - 0.054) = arc-cos(0.946) = ~19 degrees. Please take a look at what EZNEC says about the standing wave phase shift in 1/4WL of wire at: http://www.qsl.net/w5dxp/travstnd.GIF and please tell us again how you used a current with an unchanging flat phase to try to measure the phase shift through a coil. > Well, it's been over a year now, and all I've seen is the same > unsupported theory with no evidence to contradict the contrary evidence > which has been presented. No evidence? Even EZNEC says one cannot use standing wave current phase to measure phase shift. I told you that fact over a year ago. Your phase measurement methods are just as invalid today as they were a year ago. > When a belief stays fixed in spite of both contradictory solid theory > and measurements, it fits into the category of religion, not science. You are talking about your religious method of using the unchanging standing wave current phase to try to measure a phase shift. EZNEC says that is not a valid approach. Regarding the cos(kz)*cos(wt) term in a standing wave: > Gene Fuller, W4SZ wrote: >> In a standing wave antenna problem, such as the one you describe, there is no >> remaining phase information. Any specific phase characteristics of the traveling >> waves died out when the startup transients died out. >> >> Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen again. >> >> The only "phase" remaining is the cos (kz) term, which is really an amplitude >> description, not a phase. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223242 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Fri, 7 Apr 2006 09:47:14 -0400 Roy, please see my other posting, otherwise, I really promise to do the step by step article, which will try to explain, correlate real life measurements and modeling and present the comprehensive case of current being different across antenna loading coils. Will do that with cooperation of other "defenders" that contributed to "our" cause. There is no point of going back and forth on tangents. We will measure, show the reality and then apply some theory, explanation and summary of what is going on. I hope it will correct misconceptions, provide better understanding and benefit in proper modeling and design of loaded antenna elements and systems. Otherwise, I think we have reached point, when it is pointless to go around in circles and argue that what IS, CAN'T BE, because..... Yuri, K3BU "Roy Lewallen" wrote in message news:123c2oranvatgf4@corp.supernews.com... > Of course loading coils can be expressed in electrical degrees. But > extrapolating this to mean that a loading coil has the same properties as > an antenna with the same number of "degrees" has no justification. > > Yuri's theory was shown to be false not only by many of the good technical > arguments given here in this thread, but also by a careful measurement I > made over a year ago. I built a 33 foot high vertical and loaded it at the > bottom with a toroidal inductor to resonate it at 3.8 MHz. The coil > "replaced" 33.4 electrical degrees of antenna. Yuri's theory predicts that > the current at the top of the inductor should be 16.5% less than that at > the bottom, with a phase shift of 33.4 degrees. What I measured was a > current drop of 5.4% and no measurable phase shift across the inductor. > Both the description of the setup and the detailed results were posted on > this newsgroup on Nov. 11, 2003, with the subject title "Re: Current in > antenna loading coils controversy - new measurement". Anyone can find > those postings with groups.google.com. > > Yuri's response, also on Nov. 11, 2003 was to complain about my > methodology, declare that he was still right, and state "I will measure > things myself, try to verify previous measurements and then come up with > conclusions and 'theory'." > > On Nov. 12, 2003, he posted: "I will be making snap-on current probe, > which will make it easier to slide along the element and observe the > current without the disturbance to the antenna and will be a bit different > over the thermocouple meters. Just need a bit more time." > > Well, it's been over a year now, and all I've seen is the same unsupported > theory with no evidence to contradict the contrary evidence which has been > presented. > > When a belief stays fixed in spite of both contradictory solid theory and > measurements, it fits into the category of religion, not science. So it's > appropriate that Yuri speaks in terms of an explanation being a "heresy". > What's next, "good" and "evil" theories? > > Roy Lewallen, W7EL > > Yuri Blanarovich wrote: >> W8JI and other unbelievers that antenna and loading coils can not be >> expressed in electrical degrees, can find another example in ON4UN's Low >> Band DXing book, 4th edition, page 9-47, Fig 9-58, showing loaded >> vertical with mast being 40 deg. 59.6 ft. long, loading coil of 144 uH >> taking (replacing radiator of) 40 deg and whip of 10 deg and 14.9 ft >> long, for overall 90 deg electrical and quarter wave resonant system. >> Soooo, to anyone outside of "equal current worshippers" it is obvious >> that coil is replacing 40 deg worth of radiator and it would drop >> equivalent amount of current across the coil that corresponds to the >> length of radiator that coil replaces, because rest of the "straight" >> radiator FORCES IT TO DO - because of standing wave and current. >> >> Such a heresy! >> Theeere is your sign! >> >> Yuri, K3BU/m >> Article: 223243 of rec.radio.amateur.antenna From: "Cecil Moore" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: <9CuZf.9121$4L1.3131@newssvr11.news.prodigy.com> Date: Fri, 07 Apr 2006 14:24:05 GMT "Roy Lewallen" wrote: > Of course loading coils can be expressed in electrical degrees. But > extrapolating this to mean that a loading coil has the same properties > as an antenna with the same number of "degrees" has no justification. I haven't heard anybody make that assertion in years. Coils occupy whatever number of degrees that they occupy. The technical fact is that standing wave current phase cannot be used as the method of measuring the number of degrees. The graphic at http://www.travstnd.GIF shows why. The standing wave current phase is unchanging unless the monopole length goes over 1/4WL. Here's what you said earlier: >I said that Cecil's phase measurements agree with EZNEC (and generally >accepted theory) -- there should be almost no phase shift in the current >along the wire. If there's no phase shift along the wire, why would you expect to measure phase shift through a coil. After you made the above posting, I thought you understood that - but apparently not. I told you that your phase shift measurement was invalid a year ago and it is just as invalid now as it was then. There is no phase information contained in standing wave current phase. This is the basic misconception that has resulted in invalid data reported by you. > What I measured was a current drop of 5.4% and no measurable phase shift > across the inductor. But Roy, you used standing wave current phase to try to measure the phase shift across the inductor. The standing wave current phase is known to be unchanging in a wire. Why would you expect it to change through a coil? As Gene Fuller says, the only phase information in the standing wave current is in the magnitude measurement. If the magnitude changed by 5.4%, the phase shift was roughly arc-cos(1 - 0.054) = arc-cos(0.946) = ~19 degrees. Please take a look at what EZNEC says about the standing wave phase shift in 1/4WL of wire at: http://www.qsl.net/w5dxp/travstnd.GIF and please tell us again how you used a current with an unchanging flat phase to try to measure the phase shift through a coil. > Well, it's been over a year now, and all I've seen is the same > unsupported theory with no evidence to contradict the contrary evidence > which has been presented. No evidence? Even EZNEC says one cannot use standing wave current phase to measure phase shift. I told you that fact over a year ago. Your phase measurement methods are just as invalid today as they were a year ago. > When a belief stays fixed in spite of both contradictory solid theory > and measurements, it fits into the category of religion, not science. You are talking about your religious method of using the unchanging standing wave current phase to try to measure a phase shift. EZNEC says that is not a valid approach. Even Gene Fuller says there is zero phase information in standing wave current wave and he generally agrees with you. Regarding the cos(kz)*cos(wt) term in a standing wave: > Gene Fuller, W4SZ wrote: >> In a standing wave antenna problem, such as the one you describe, there is no >> remaining phase information. Any specific phase characteristics of the traveling >> waves died out when the startup transients died out. >> >> Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen again. >> >> The only "phase" remaining is the cos (kz) term, which is really an amplitude >> description, not a phase. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223244 of rec.radio.amateur.antenna From: "Cecil Moore" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144391840.390341.262170@e56g2000cwe.googlegroups.com> <123c2vmeq69bv41@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Fri, 07 Apr 2006 14:27:33 GMT "Roy Lewallen" wrote: > I'm afraid that the proponents of the alternative theories aren't > subject to either modeling or measurement results. There's already ample > theoretical, modeling, and measurement evidence to show that the theory > is faulty; further efforts would be a waste of time. Roy, it is you who are ignoring the results of EZNEC. EZNEC proves that one cannot use standing wave current phase to measure the phase shift through a wire, much less through a coil. To see why, take a look at: http://www.qsl.net/w5dxp/travstnd.GIF The standing wave current is absolutely FLAT. It cannot be used for any valid measurement. -- 73, Cecil, W5DXP Article: 223245 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1143142526.021154.67050@e56g2000cwe.googlegroups.com> <0hf13258667d7d0m648bf6rbgm6ecrj2sl@4ax.com> <5qaYf.6$qO.0@fe10.lga> <1144131328.322721.32520@t31g2000cwb.googlegroups.com> <1k5532h8scbtg8e8iscn4ncjuusoa7ddai@4ax.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Fri, 07 Apr 2006 14:40:36 GMT "Ian White GM3SEK" wrote : > It certainly *is* possible to make a correct analysis of a short > coil-loaded antenna in terms of forward, reflected and standing waves of > current. The real question is: Is it possible for Ian White to make a mistake? If the answer is, 'yes', then it possibly could be your mistake and not mine. Or both of us could be making mistakes. > But jigsaw puzzles have unbreakable rules: a new piece must fit EXACTLY > into the gap that it fills; and everywhere around its edges, the picture > MUST join up EXACTLY. If it fails to fit exactly and in every detail, > then it isn't the right piece. But what if somebody mutilated one of the pieces? That final piece is not going to fit whether it is correct or not. That's what you have done - mutilate one of the pieces so the final piece doesn't fit. > Returning to this particular gap in the picture of antenna engineering, > concerning short loaded antennas, we can see that it's only a small gap. > It is surrounded by large areas of existing knowledge that interlock > solidly and completely. That means we can be confident there will be > nothing different or special happening inside that gap. But some of the concepts in that large area of existing "knowledge" are false. I know what your misconception is. If you will use your ears instead of your mouth, you could understand what that misconception really is. > Cecil wants to try a method based on forward, reflected and standing > waves, and that's just fine. Not only is it a fine way to deal with the problem, its use exposes your misconception. Wouldn't you like to correct that misconception? > But Cecil's new piece for the puzzle uses new and special definitions > and properties for electric current, inductance, and travelling and > standing waves - they are not the same as in all the surrounding pieces. > To me, that is absolute proof that his new piece doesn't fit. All it means is that you mutilated one of the pieces. Fix your mutilated piece and my piece will fit. > Exactly why it doesn't fit remains a matter for debate. But I am > fundamentally sure of the *fact* that it doesn't. I agree it doesn't fit but the reason it doesn't fit is your mutilated piece installed previously. The mutilated piece is the nature of standing wave current and I know exactly how it was mutilated. If you are willing to discuss that narrow issue from a purely technical standpoint, I can show you how to fix your piece so that my piece will fit nicely just as it should. -- 73, Cecil, W5DXP Article: 223246 of rec.radio.amateur.antenna From: "Cecil Moore" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Fri, 07 Apr 2006 15:16:09 GMT "Yuri Blanarovich" wrote: > Otherwise, I think we have reached point, when it is pointless to go around > in circles and argue that what IS, CAN'T BE, because..... Yuri, I think it is obvious that some people are suffering from misconceptions. The misconception that the "experts" are suffering from has *nothing* to do with coils. That's the reason the coil discussion has gone in circles. There may not be anything wrong with the coil concepts. The misconception is about standing wave current VS traveling wave current. The "experts" have asserted that "current is current" and that standing wave current is the same as traveling wave current even though they have different equations. Even EZNEC recognizes the difference between standing wave current and traveling wave current. I took a quarter wavelength of wire and drove it as a standing wave wire and as a traveling wave wire. The piece of wire was identical in both cases. I've posted the EZNEC results a number of times and none of the "experts" have responded. Here they are again: The corresponding EZNEC files are available at: http://www.qsl.net/w5dxp/TravWave.EZ I(x,t)=Io*cos(kx+wt) http://www.qsl.net/w5dxp/StndWave.EZ I(x,t)==Io*cos(kx)*cos(wt) % along current in current in wire #2 TravWave.EZ StndWave.EZ 0.28% 0.9998 at -0.99 deg 0.9996 at 0 deg 9.72% 0.9983 at -9.39 deg 0.9843 at -0.03 deg 19.7% 0.9969 at -18.23 deg 0.9454 at -0.05 deg 30.3% 0.9957 at -27.59 deg 0.8843 at -0.06 deg 39.7% 0.9949 at -35.96 deg 0.8023 at -0.08 deg 49.7% 0.9945 at -44.84 deg 0.7014 at -0.09 deg 60.3% 0.9945 at -54.20 deg 0.5840 at -0.09 deg 69.7% 0.9949 at -62.58 deg 0.4528 at -0.10 deg 79.7% 0.9956 at -71.43 deg 0.3110 at -0.11 deg 89.7% 0.9965 at -80.27 deg 0.1616 at -0.11 deg 99.7% 0.9976 at -89.14 deg 0.0061 at -0.11 deg These values reported by EZNEC are graphed at: http://www.qsl.net/w5dxp/travstnd.GIF Their differences are obvious. One might even argue that they are opposites. The traveling wave magnitude looks like the standing wave phase. The traveling wave phase looks like the standing wave magnitude. That fits perfectly with Gene Fuller's assertion that there is no phase information in standing wave current phase. The only phase information in the standing wave current is in the magnitude. Once the "experts" realize that is the source of their misconception, everything will fall into place. Again, it is NOT about coils. It is all about misconceptions involving standing wave current. -- 73, Cecil, W5DXP Article: 223247 of rec.radio.amateur.antenna From: "Cecil Moore" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: <%CvZf.56025$F_3.39775@newssvr29.news.prodigy.net> Date: Fri, 07 Apr 2006 15:33:15 GMT "Reg Edwards" wrote: > I fail to see what you are all arguing about. Here's the argument in a nutshell, Reg. Can standing wave current phase be used to determine the phase shift through a coil (or through a wire)? Some of us say, No. Some of the "experts" say, Yes, but so far have failed to explain how or why that is a valid measurement technique. -- 73, Cecil, W5DXP Article: 223248 of rec.radio.amateur.antenna From: Me Subject: Re: Balloon lifted wire antenna? References: <220320061901558586%artie.m@gNOSPAMmail.com> <1143475830.028569.213520@i40g2000cwc.googlegroups.com> Message-ID: Date: Fri, 07 Apr 2006 16:16:08 GMT In article , N7ZZT - Eric Oyen wrote: > ok, > the original poster did not clarify as to which isotope of hydrogen was > being used. H2 is a stable isotope (and yeah, I do stand corrected on that > point). Still, the energies required to get 2 protons and 2 electrons to > get along are fairly high. Hydrogen (H not 1 or 2 or bloody 3...) is very > small (smaller than helium) and will tend to slip through most materials > (except for possibly the extremely dense materials such as Polonium). > > perhaps in the future, we should be a bit more concise about things like > this..... now I know that diatomic hydrogen is fairly common in nature (as > in H2O, CH2 and a few others). I would have to ask a question of some folks > over at ASU to see what they use for high atmosphere balloons. > > -- > DE N7ZZT > Eric Oyen > Phoenix, Arizona > e-mail: n7zzt(at)hotmail(dot)com > the difference between intelligence and stupidity is that intelligence > has its limits. I wonder if you can still remember ANY of your High School Chemistry or Physics. H2 isn't an Isotope of anything. An Isotope is a chemically identical atom that has a different number of NEUTRONS than others of the same Chemical Element. Whether it is Diatomic, multiatonic, or singular in nature has NO bearing on if it is an Isotope. Hydrogen has three isotopes. Hydrogen = One proton and one electron Detirium = One proton, one neutron, and one electron Tritium = One proton, two neutrons and one electron Me a NitroOrganic Chemist, in a previous life Article: 223249 of rec.radio.amateur.antenna From: "Cecil Moore" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <%CvZf.56025$F_3.39775@newssvr29.news.prodigy.net> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: <9swZf.56046$F_3.43400@newssvr29.news.prodigy.net> Date: Fri, 07 Apr 2006 16:29:57 GMT "Reg Edwards" wrote: > I couldn't care two hoots about standing waves, whatever they are. The "experts" have that same problem, Reg, yet they are using standing wave current phase to try to measure phase shift through a coil, a known invalid approach since standing wave current phase doesn't contain any phase information. -- 73, Cecil, W5DXP Article: 223250 of rec.radio.amateur.antenna From: "Cecil Moore" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Fri, 07 Apr 2006 16:42:01 GMT wrote: > It is the stray capacitance from the inductor to the outside world that > allows any difference in current. Not the standing waves, not the > missing area of antenna. You are using standing wave current to try to prove your concepts are valid. If you don't take time to understand standing wave current, you will never correct those misconceptions. Standing wave current phase contains no phase information. Therefore, standing wave current phase cannot be used to measure the phase shift through a wire or a coil. The only phase information in a standing wave current is in the magnitude which roughly follows a cosine function distorted by the fields in the loading coil. If the current at the bottom of the coil is 1.0 amps and the current at the top of the coil is 0.7 amps, the phase shift through the coil is *roughly* arc-cos(0.7) = ~45 degrees. As Gene Fuller says, there's no phase information in standing wave current phase. All the phase information is embedded in the magnitude. That's easy to see from the I(x,t) = Io*cos(kx)*cos(wt) equation for standing wave current. It's also easy to see from: http://www.qsl.net/w5dxp/travstnd.GIF plotted from EZNEC data. -- 73, Cecil, W5DXP Article: 223251 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Message-ID: Date: Fri, 07 Apr 2006 17:49:13 GMT Cecil Moore wrote: > I've posted the EZNEC results a > number of times and none of the "experts" have responded. Cecil, I wonder why? Fool me once, shame on you. Fool me twice, shame on me. Fool me thrice, what an idiot I must be. 73, Gene W4SZ Article: 223252 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Message-ID: Date: Fri, 07 Apr 2006 17:55:39 GMT Cecil Moore wrote: > > The misconception is about standing wave current VS traveling wave current. > The "experts" have asserted that "current is current" and that standing wave > current is the same as traveling wave current even though they have > different equations. Cecil, So how is your study of the NEC documents going? I learn something new every time I plow through the mathematical discussion. I find current discussed on almost every page, but I am still searching for the part that discusses standing waves and traveling waves. If you could help me find that section it would be appreciated. 73, Gene W4SZ Article: 223253 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: How get RF through a sealed window? Message-ID: <7pad32hah7fjtd00c044p6plb4t7nk6pd1@4ax.com> References: Date: Fri, 07 Apr 2006 18:13:24 GMT On 6 Apr 2006 11:06:22 -0500, mcalhoun@ksu.edu wrote: >I gave a presentation on "How Ham Radio Can Help You in an Emergency" >to 70 Emergency Management types last week, and the windows in the >building which hosted the meeting were NOT open-able (so I "made do" >with an inside VHF antenna and didn't even try to demonstrate HF). > >But in emergency/expedient situations, it would be really handy if one >could pass at HF, say, 100 watts of RF energy through a window (I >visualize some foil strips and an inductor or two to "tune out" the >capacitance) to an external antenna. If the window is sealed, and on something other than the first floor, how are you going to attach an antenna on the outside? It seems getting RF through the glass might be the least of your problems. If it's a hotel, ask for a balcony... bob k5qwg > >I've been told that the April, 1989, issue of Ham Radio magazine carried >an article "Easy antenna access for urban apartment dwellers" (for 15 >meters) by Bryan Bergeron, NU1N, starting on page 18. > >I'd sure like to read that article; can anyone send me a copy? Article: 223254 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Message-ID: Date: Fri, 07 Apr 2006 18:19:54 GMT Gene Fuller wrote: > Cecil Moore wrote: > >> I've posted the EZNEC results a >> number of times and none of the "experts" have responded. > > Cecil, > I wonder why? > Fool me once, shame on you. > Fool me twice, shame on me. > Fool me thrice, what an idiot I must be. Gene, I don't make fools of the "experts". They do that to themselves through such statements as "current is current", implying that standing wave current is identical to traveling wave current which you know is NOT the case (thanks for your earlier posting). Wouldn't it be better to explain standing wave current to the "experts" in a private email than attacking me here for "fooling the experts"? You and I are in essential agreement. It's the "experts" who use standing wave current phase to measure phase who are, in your words above, the "idiots". Considering a technical discussion to be fooling the "experts" speaks volumes, doesn't it? And indeed, Ian said it best. He said something to the effect that I try to sucker the experts into an argument when I am right. That says it all and shows why the "experts" won't engage me when they know that they are wrong. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223255 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Message-ID: Date: Fri, 07 Apr 2006 18:28:43 GMT Gene Fuller wrote: > So how is your study of the NEC documents going? I don't understand it yet. But EZNEC does understand it since EZNEC reports the correct results for both traveling wave current and standing wave current. I just downloaded an updated graphic to http://www.qsl.net/w5dxp/travstnd.GIF but qsl.net is so unreliable I haven't been able to view it yet. > I learn something new every time I plow through the mathematical > discussion. I find current discussed on almost every page, but I am > still searching for the part that discusses standing waves and traveling > waves. Glad you asked, Gene, regarding the cos(kz)*cos(wt) term in a standing wave: Gene Fuller, W4SZ wrote: > In a standing wave antenna problem, such as the one you describe, > there is no remaining phase information. Any specific phase > characteristics of the traveling waves died out when the startup > transients died out. > > Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be > seen again. > > The only "phase" remaining is the cos (kz) term, which is really an > amplitude description, not a phase. One can see from my above graphic that EZNEC indeed does differentiate between traveling waves and standing waves. So how does EZNEC do that? EZNEC agrees with your above posting but I don't yet know how it knows. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223256 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <1144433868.856137.150940@z34g2000cwc.googlegroups.com> Message-ID: Date: Fri, 07 Apr 2006 18:36:41 GMT w8ji@akorn.net wrote: > I'm still trying to find out why my meter measures standing wave > current and not "real current", or whatever the heck he is saying. It's all explained by the EZNEC data that I have posted half a dozen times before to which you haveyet to responded. In case you could possibly have missed it, here it is again: % along current in current in wire #2 TravWave.EZ StndWave.EZ 0.28% 0.9998 at -0.99 deg 0.9996 at 0 deg 9.72% 0.9983 at -9.39 deg 0.9843 at -0.03 deg 19.7% 0.9969 at -18.23 deg 0.9454 at -0.05 deg 30.3% 0.9957 at -27.59 deg 0.8843 at -0.06 deg 39.7% 0.9949 at -35.96 deg 0.8023 at -0.08 deg 49.7% 0.9945 at -44.84 deg 0.7014 at -0.09 deg 60.3% 0.9945 at -54.20 deg 0.5840 at -0.09 deg 69.7% 0.9949 at -62.58 deg 0.4528 at -0.10 deg 79.7% 0.9956 at -71.43 deg 0.3110 at -0.11 deg 89.7% 0.9965 at -80.27 deg 0.1616 at -0.11 deg 99.7% 0.9976 at -89.14 deg 0.0061 at -0.11 deg I have graphed these EZNEC results and they are available at: http://www.qsl.net/w5dxp/travstnd.GIF The corresponding EZNEC files are available at: http://www.qsl.net/w5dxp/TravWave.EZ http://www.qsl.net/w5dxp/StndWave.EZ Would you please explain why you are avoiding these results which expose your misconceptions about standing wave current unless exposing your misconceptions is what you are avoiding? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223257 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> Message-ID: Date: Fri, 07 Apr 2006 19:04:03 GMT w8ji@akorn.net wrote: > You can weave a little tidbit of fact into a big misconception or > diversion if you like, but don't expect others to buy into the > misconception. When are you going to discuss the technical difference between I(x,t)=Io*cos(kx+wt) and I(x,t)=Io*cos(kx)*cos(wt)? The only place those two currents are equal is when x=0. At any other point, they are virtually opposites of each other. The differences in those two equations is what led you to believe the currents at each end of a coil are identical based on measurements. You guys used a signal, the standing wave current signal, that is incapable of distinguishing a phase shift even in a wire, much less in a coil. > The current you measure with a clamp on meter or any other reliable > current meter that does not greatly perturb the circuit is the current > that causes radiation, it is the current that causes heating, and it is > the current we would use to calculate power. There's absolutely no argument about that. Both forward waves and reflected waves radiate so standing waves obviously radiate. Both forward waves and reflected waves cause I^2*R losses. Stating such obvious technical facts is a diversion and a waste of words. > The phase of that current is the phase of the current that causes > radiation, heating, and that we would use to calculate patterns. The phase of standing wave current is unchanging. That's why we get broadside radiation from a 1/2WL standing wave dipole and end fire radiation from a traveling wave antenna. But again, stating such obvious technical facts is a diversion and a waste of words. When are you going to discuss the actual technical issues? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223258 of rec.radio.amateur.antenna From: John - KD5YI Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Message-ID: <7VyZf.79$Q92.56@trnddc04> Date: Fri, 07 Apr 2006 19:17:23 GMT Cecil Moore wrote: > > These values reported by EZNEC are graphed at: > > http://www.qsl.net/w5dxp/travstnd.GIF Clicking that URL causes Firefox to report: "The operation timed out when attempting to contact proxy.qsl.net." Pasting that URL into Opera causes it to just sit there and do nothing. I just thought you'd like to know. Cheers, John Article: 223259 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <7VyZf.79$Q92.56@trnddc04> Message-ID: Date: Fri, 07 Apr 2006 19:26:33 GMT John - KD5YI wrote: > Cecil Moore wrote: >> These values reported by EZNEC are graphed at: >> http://www.qsl.net/w5dxp/travstnd.GIF > > Clicking that URL causes Firefox to report: > "The operation timed out when attempting to contact proxy.qsl.net." > Pasting that URL into Opera causes it to just sit there and do nothing. > I just thought you'd like to know. I apologize for qsl.net being so unreliable. Please try again later. I'm going to get a more reliable web server just as soon as I get a round tuit. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223260 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Fri, 07 Apr 2006 12:56:37 -0700 Message-ID: <123dgvmajb4ihd5@corp.supernews.com> References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> Yuri Blanarovich wrote: > Roy, > please see my other posting, otherwise, I really promise to do the step by > step article, which will try to explain, correlate real life measurements > and modeling and present the comprehensive case of current being different > across antenna loading coils. Will do that with cooperation of other > "defenders" that contributed to "our" cause. There is no point of going back > and forth on tangents. We will measure, show the reality and then apply some > theory, explanation and summary of what is going on. > I hope it will correct misconceptions, provide better understanding and > benefit in proper modeling and design of loaded antenna elements and > systems. > Otherwise, I think we have reached point, when it is pointless to go around > in circles and argue that what IS, CAN'T BE, because..... Before you get too carried away, look back in this thread where Cecil posted a URL to his web site where he had an EZNEC (helical wire) model of a coil at the base of a short whip. It showed significant current drop from the bottom to the top, although no significant phase shift. I replaced the whip part of the antenna with a wire directly to ground >from the top of the coil which contained a lumped RC to substitute for the whip's impedance. The drop across the coil remained the same. So in the course of developing your theory, you should explain why this happens, since there are no longer the traveling and standing waves which were on the whip. This model was, and still is, posted on my web site. Then, to illustrate that the current drop from bottom to top is due to shunt C, I removed the ground in the model, converting the model to free space. I connected the bottom of the coil to the bottom of the new wire with a wire instead of via the ground connection. The current drop from bottom to top of the coil disappeared. (There's still a minor difference due to several factors I mentioned in my posting.) The fact that the current drop is the same for an antenna and for a lumped circuit with the same impedance was also verified by measurements I made and posted over a year ago. Those model results are consistent with what I, Tom, and others have been saying, and consistent with classical, known, circuit theory. They aren't consistent at all with all this standing wave - traveling wave - antenna replacement business. I've looked very carefully at the models and concluded that EZNEC is operating well within its capabilities, so the results are valid. So for starters, why don't you explain how your theory fits with the existing model results? Why is the current drop the same with an antenna and for a lumped circuit? Why does removing ground make the current drop go away? Why is there no significant phase shift in current from bottom to top? Conventional theory can explain this. Can yours? As for your promise to write the article, I have to point out that you've made this promise before without delivering. So I'm not exactly holding my breath waiting for it. I'm sure it'll make interesting reading, though, and it's a revolutionary enough theory that the IEEE, or at the very least QEX, should be happy to publish it when it's finally complete. Roy Lewallen, W7EL Article: 223261 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> Message-ID: <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> Date: Fri, 07 Apr 2006 20:06:23 GMT Roy Lewallen wrote: > Before you get too carried away, look back in this thread where Cecil > posted a URL to his web site where he had an EZNEC (helical wire) model > of a coil at the base of a short whip. It showed significant current > drop from the bottom to the top, although no significant phase shift. It showed a 10 degree phase shift. I've always said the phase shift is what it is but it is NOT zero. 10 degrees is definitely NOT zero even though you measured zero degrees shift. Wonder what was wrong with your measurements? > So in > the course of developing your theory, you should explain why this > happens, since there are no longer the traveling and standing waves > which were on the whip. Oh my, Roy, are you saying that zero ohms doesn't cause a reflection? If so, your misconceptions are worse than I thought. A short to ground causes exactly the same total reflection as an open-circuit, just with different phases. I would have expected you to realize that. > I've looked very carefully at the models > and concluded that EZNEC is operating well within its capabilities, so > the results are valid. Yes, they are and they shoot down your argument. Please explain the results posted at: http://www.qsl.net/w5dxp/travstnd.GIF > So for starters, why don't you explain how your theory fits with the > existing model results? You first, Roy, since you disagree with EZNEC. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223262 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> Message-ID: Date: Fri, 07 Apr 2006 21:58:33 GMT Cecil Moore wrote: > Please explain the results posted at: http://www.qsl.net/w5dxp/travstnd.GIF Cecil, You may believe it is obvious, but it is not quite clear what you are trying to show in that figure. On the left side, traveling wave, it appears that "magnitude" means Io. On the right side, standing wave, it appears that "magnitude" means Io cos(kx). The gist of your position seems to be that somehow the traveling wave is more powerful, or at least different, since the area under the current magnitude curve is larger. In reality, however, it is necessary to pick a single time at which to compare the two cases. It is of little value to look at some sort of overall envelope for the traveling wave. The correct magnitude of the traveling wave never has the shape of the overall envelope. Pick a single time, say when wt is equal to zero or equal to pi. Then compare the curves. In fact, if you pick any single time for the left side the resulting curve shape will look a lot like the right side. 73, Gene W4SZ Article: 223263 of rec.radio.amateur.antenna From: ml Subject: Re: Given my restrictions, how can I improve my HF antenna? References: <123bunsakbdii6f@corp.supernews.com> Message-ID: Date: Sat, 08 Apr 2006 00:17:34 GMT In article <123bunsakbdii6f@corp.supernews.com>, dplatt@radagast.org (Dave Platt) wrote: > In article , > Thomas anonymous wrote: > > >I'm renting a basement suite and have an Icom 706mkII & MFJ-949E antenna > >tuner, and I need a better HF antenna arrangement than I already have > >(without going to a tower, hi). I would like to run a balanced > >feedline from the tuner to the feedpoint but the feedline has to go > >from my shack to where the feedpoint is, and that involves crossing a > >cement path --- in other words, because the feedline has to lie on top > >of cement it can't really be anything other than coax. > > You could make up a section of shielded balanced line, to get the feed > across the cement without having it couple messily into the ground. > > A shielded balanced line can be made from two equal-length runs of > coax cable. RG-6 would work; aluminum-jacketed cable-TV hardline > might be even better from an electrical standpoint although its > rigidity might be inconvenient. Connect the shields/braids of the two > sections of coax together at each end, use the center conductors > to carry the signal, and fasten the two coaxes together in some > convenient fashion (an occasional nylon wire-tie would do, I believe). > > The impedance of such a line will be twice that of the individual > pieces of coax - i.e. 150 ohms if you use RG-6. No need to worry > about matching it to the rest of the balanced feedline. You can use > 300 or 450 or 600-ohm (nominal) balanced line where convenient, to > keep the losses as low as practical, and this 150-ohm shielded > balanced pair where necessary. The losses should be acceptable, and > will certainly be less than if you plumbed the whole distance with 50- > or 75-ohm coax. perhaps just making a wood board or somthing to fill a few inches and cut to allow the window to close on it, w/foam too and drill a hole in the wood to pass the wire and have it centered enought away on all sides from metal then it dosn't disturbe or damage the building/window etc Article: 223264 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Current across the antenna loading coil - from scratch Date: Fri, 07 Apr 2006 19:35:37 -0500 Message-ID: <123e1b1ntsbm27e@corp.supernews.com> References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> Cecil Moore wrote: > w8ji@akorn.net wrote: > >> So what exactly is the importance of this current YOU are talking >> about? > > > All the diversionary BS trimmed from your posting. Bottom line, > the equation for standing wave current is: > > I(x,t) = Io*cos(kx)*cos(wt) > > The equation for traveling wave current is: > > I(x,t) = Io*cos(ks+wt) > > Since you obviously don't comprehend the difference, please > dust off your old math book and take a look. > > In case you need a graphics reference for those two equations, > you can find it at: http://www.qsl.net/w5dxp/travstnd.GIF > > You will find the two above currents are virtually opposites > of each other. > > In particular, standing wave current phase CANNOT be used to > determine the phase shift through a wire or through a coil > because its phase never changes in a 1/4WL monopole. > > I can hardly say it better than Gene Fuller who said: > Regarding the cos(kz)*cos(wt) term in a standing wave: > >> Gene Fuller, W4SZ wrote: >> >>> In a standing wave antenna problem, such as the one you describe, >>> there is no remaining phase information. Any specific phase >>> characteristics of the traveling waves died out when the startup >>> transients died out. >>> >>> Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen >>> again. >>> >>> The only "phase" remaining is the cos (kz) term, which is really an >>> amplitude description, not a phase. > > > Please tell us what it is about Gene's posting that you don't > understand. Cec; Please answer the man's question. Don't prevaricate. Don't deviate. Answer the damn question. Except for this particular subject I have great admiration for you knowledge and have learned from you. This subject seems to be your bugaboo. I have completely lost track of what the object of the exercise is. Dave N Dave N Article: 223265 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> Message-ID: Date: Sat, 08 Apr 2006 00:47:17 GMT Cecil Moore wrote: > Gene Fuller wrote: > >> You may believe it is obvious, but it is not quite clear what you are >> trying to show in that figure. On the left side, traveling wave, it >> appears that "magnitude" means Io. On the right side, standing wave, >> it appears that "magnitude" means Io cos(kx). > > > No, both plots are for I(x,t). The magnitude of the traveling wave > current is constant while the phase changes with 'x'. The phase of > the standing wave current is constant while the magnitude changes > with 'x'. They are virtually opposites of each other. > >> It is of little value to look at some sort of overall envelope for the >> traveling wave. > > > Both currents are phasor RMS values along with their phases. > > I am reporting *exactly* what EZNEC reports. If you don't like > that, talk W7EL into reporting something different. Cecil, Perhaps I was not clear. I understand the plots, and I have no question that they show what EZNEC provides. My question is why you feel there is anything of significance or anything for the "gurus" to ponder. As I explained, the curves are mostly a comparison of apples to oranges. One (standing wave) shows the peak current at when the cos(wt) factor is at a maximum. The other (traveling wave) shows the envelope of all the current shapes over time. They are really two different entities, and they have virtually no application to the topic featured in the past 17,000 messages. What you call the "magnitude" of the traveling wave never actually represents the current over the length of wire at any point in time. 73, Gene W4SZ Article: 223266 of rec.radio.amateur.antenna Date: Fri, 07 Apr 2006 19:48:58 -0500 From: Tom Ring Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> Message-ID: <4437087a$0$1018$39cecf19@news.twtelecom.net> Roy Lewallen wrote: > So for starters, why don't you explain how your theory fits with the > existing model results? Why is the current drop the same with an antenna > and for a lumped circuit? Why does removing ground make the current drop > go away? Why is there no significant phase shift in current from bottom > to top? Conventional theory can explain this. Can yours? > > As for your promise to write the article, I have to point out that > you've made this promise before without delivering. So I'm not exactly > holding my breath waiting for it. I'm sure it'll make interesting > reading, though, and it's a revolutionary enough theory that the IEEE, > or at the very least QEX, should be happy to publish it when it's > finally complete. > > Roy Lewallen, W7EL Roy, I will make you a bet. Lunch, if you might be at Central States this year. Not Gonna Happen. They are not interested in reality. They are not interested in engineering. They do not want to understand physics, or they are not capable. It matters not. I have been watching, and reading, and would like to see you, and the others, stop beating a very dead horse. Cecil and Yuri will never get it. Tom K0TAR Article: 223267 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> Message-ID: Date: Sat, 08 Apr 2006 00:49:23 GMT Gene Fuller wrote: > You may believe it is obvious, but it is not quite clear what you are > trying to show in that figure. Gene, I previously responded in words that I thought you would understand, based on your previous understanding. It occurred to me during my walk that not every reader is an engineer, not every engineer is a EE, and not every EE also has a math degree. Here it is in easier to understand terms. Given the 1/4WL conductor and the web page at: http://www.qsl.net/w5dxp/travstnd.GIF The way to measure phase shift through a wire carrying the traveling wave current is to put a current probe at location A and location B, and measure the phase shift between those two equal magnitude sine waves. If a coil exists in the circuit, that would also be the way to get a rough measure of the phase shift across the coil. Example: The phase shift from 30% to 60% in the traveling wave antenna is taken from the tabular data as 54.2-27.6 = 26.6 degrees. The phase information is in the *phase* in a traveling wave. For the standing wave current, the situation is completely different. The phase measured between any two current probes will always be zero. The phase of a standing wave current is useless for measuring phase shift. The way to extract the phase information is to measure the *amplitude* at two points and then calculate the phase shift by taking the arc-cos of the normalized amplitude. Example: The phase shift from 30% to 60% in the standing wave antenna is arc-cos(0.8843) - arc-cos(0.5840) = 26.5 degrees. The phase information is in the *amplitude* in a standing wave. Thus in both antennas, the phase shift in 30 percent of the wire is about 27 degrees. (90*.3 = 27) If we had a coil installed in that 30 degrees of the antenna instead of a wire, the same concepts would apply. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223268 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> <123e1b1ntsbm27e@corp.supernews.com> Message-ID: <1TDZf.9260$4L1.170@newssvr11.news.prodigy.com> Date: Sat, 08 Apr 2006 00:56:29 GMT David G. Nagel wrote: > Please answer the man's question. Don't prevaricate. Don't deviate. > Answer the damn question. Maybe one of my other postings answers the question for you. I'm not prevaricating or deviating. I'm answering the questions to the best of my ability. Gene's posting is one of the best answers to Tom's questions that I have seen. Gene says there is ZERO information in standing wave phase. I agree with Gene. > Except for this particular subject I have great admiration for you > knowledge and have learned from you. This subject seems to be your > bugaboo. I have completely lost track of what the object of the exercise > is. The object of the exercise is to prove that standing wave current phase cannot be used to measure the phase through a wire or coil or anything else. The phase of a standing wave is already known and is unchanging. The only phase information in a standing wave current is contained in the amplitude. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223269 of rec.radio.amateur.antenna Date: Fri, 07 Apr 2006 19:57:08 -0500 From: Tom Ring Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> Message-ID: <44370a64$0$1018$39cecf19@news.twtelecom.net> Roy Lewallen wrote: > So for starters, why don't you explain how your theory fits with the > existing model results? Why is the current drop the same with an antenna > and for a lumped circuit? Why does removing ground make the current drop > go away? Why is there no significant phase shift in current from bottom > to top? Conventional theory can explain this. Can yours? > > As for your promise to write the article, I have to point out that > you've made this promise before without delivering. So I'm not exactly > holding my breath waiting for it. I'm sure it'll make interesting > reading, though, and it's a revolutionary enough theory that the IEEE, > or at the very least QEX, should be happy to publish it when it's > finally complete. > > Roy Lewallen, W7EL Sorry, I forgot to mention that they also don't appear to understand math, or the fact that "complex numbers" are quite simple if you went to engineering school and own an HP15 calculator. Mine still works fine. If you had trouble with the previous statement, Cecil and Yuri, I meant that your "phasor" math is trivial. At best 2nd year engineering. And yes, we do understand it. A lot more than you do apparently. tom K0TAR Article: 223270 of rec.radio.amateur.antenna Message-ID: <44370B03.2070702@fuse.net> Date: Fri, 07 Apr 2006 20:59:47 -0400 From: jawod Subject: Re: Thin & Fat Yagis References: west wrote: > Take 2 Yagis or verticals built with aluminum tubing. Both are identical > except the tubing in one is twice the diameter of the other. Besides size, > what will the property differences be between the two? Will they load up > the same? I don't mean to be flippant, but this question has been on my > mind for a long time and I couldn't find the answer. All comments > appreciated. Thank you. > > 73's, west > AF4GC > > If I'm not mistaken ( a dubious assumption ), I seem to remember that "fatter" elements produce wider bandwidths (i.e., lower SWR over greater range of frequency). If this is not the case, please correct me. John AB8WH Article: 223271 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> Message-ID: <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> Date: Sat, 08 Apr 2006 01:00:50 GMT Gene Fuller wrote: > My question is why you feel there is anything of significance or > anything for the "gurus" to ponder. Hopefully, I answered that question in my other posting. If one wants to measure phase shift using a traveling wave current, one measures the phase shift between two points. If one wants to measure the phase shift using a standing wave current, one measures the amplitudes at two points and subtracts the arc-cosines of the normalized amplitude values. You said essentially the same thing in your earlier posting - that there is no phase information in the standing wave current phase and all the phase information is in the amplitude values. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223272 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <4437087a$0$1018$39cecf19@news.twtelecom.net> Message-ID: Date: Sat, 08 Apr 2006 01:05:53 GMT Tom Ring wrote: > They are not interested in reality. They are not interested in > engineering. They do not want to understand physics, or they are not > capable. It matters not. You are, of course, talking about QEX. Tom, maybe you can explain how to use standing wave current phase to measure the phase shift through a wire? If you can, I would really appreciate it. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223273 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <44370a64$0$1018$39cecf19@news.twtelecom.net> Message-ID: Date: Sat, 08 Apr 2006 01:16:23 GMT Tom Ring wrote: > If you had trouble with the previous statement, Cecil and Yuri, I meant > that your "phasor" math is trivial. At best 2nd year engineering. And > yes, we do understand it. A lot more than you do apparently. Well then, please prove W8JI's assertion that "current is current", i.e. that cos(kx+wt) = cos(kx)*cos(wt) at every point up and down the wire. That should be "trivial" for you. If you cannot prove that, please explain to us how and why standing wave current is different from traveling wave current. (That's what I have been doing.) During your explanation of the difference, you will realize why W7EL's standing wave phase measurements are meaningless - that there is no phase information in standing wave current phase. As Gene said, all the phase information is in the standing wave current *amplitude*, not in the phase. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223274 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Gamma. Before somebody tells me. References: Message-ID: Date: Sat, 08 Apr 2006 01:34:33 GMT Reg Edwards wrote: > But, believe it or not, under certain load conditions the reflection > coefficient Gamma can exceed unity. Indeed, at a sufficiently low > frequency, Gamma can approach 1+Sqrt(2) = 2.414 That agrees with Chipman who says it only occurs in lossy lines. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223275 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Fri, 07 Apr 2006 19:16:15 -0700 Message-ID: <123e77gn5kljfb5@corp.supernews.com> References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <4437087a$0$1018$39cecf19@news.twtelecom.net> Tom Ring wrote: > > Roy, I will make you a bet. Lunch, if you might be at Central States > this year. Are you kidding? With odds about the same as winning the lottery? > Not Gonna Happen. > > They are not interested in reality. They are not interested in > engineering. They do not want to understand physics, or they are not > capable. It matters not. > > I have been watching, and reading, and would like to see you, and the > others, stop beating a very dead horse. Cecil and Yuri will never get it. Oh, I know all that. I'm not posting in an attempt to educate Cecil and Yuri or to change their minds -- it became evident years ago that's a waste of time. The only reason I bother is in the hopes that it'll play some part in preventing some of the lurkers from getting sucked in by the flurry of informed-sounding but demonstrably wrong arguments which continue to come from those folks. It's hard to say if it's having any effect, but I think it's important to present a point of view supported by established theory, modeling, and measurement results which are all in agreement rather than letting the pseudo-science stand alone as apparent fact. Roy Lewallen, W7EL Article: 223276 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Current across the antenna loading coil - from scratch Date: Fri, 07 Apr 2006 21:18:31 -0500 Message-ID: <123e7bvrpae5c16@corp.supernews.com> References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> <123e1b1ntsbm27e@corp.supernews.com> Reg Edwards wrote: > "David G. Nagel" wrote > >>I have completely lost track of what the object of the exercise is. >> > > ======================================= > > I gave up trying just after the thread began. > > What put me off was "current across the coil" when everybody knows it > should be "current through the coil". > > It is VOLTS which appear ACROSS coils. > ---- > Reg. > > evidently Cecil doesn't. Dave Article: 223277 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> Message-ID: <3bFZf.703615$qk4.163958@bgtnsc05-news.ops.worldnet.att.net> Date: Sat, 08 Apr 2006 02:26:07 GMT Cecil, I thought you denounced and denied this "concept" earlier today. 73, Gene W4SZ Cecil Moore wrote: If we had a coil installed > in that 30 degrees of the antenna instead of a wire, the same > concepts would apply. Article: 223278 of rec.radio.amateur.antenna From: "RB" References: <123bunsakbdii6f@corp.supernews.com> Subject: Re: Given my restrictions, how can I improve my HF antenna? Message-ID: Date: Fri, 7 Apr 2006 22:03:25 -0500 Tunnel under the sidewalk and run coax through a pvc pipe to your antenna? Sidewalk tunnelling is relatively easy with a "wand" and hose. Article: 223279 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <4437087a$0$1018$39cecf19@news.twtelecom.net> <123e77gn5kljfb5@corp.supernews.com> Message-ID: Date: Sat, 08 Apr 2006 03:28:39 GMT Roy Lewallen wrote: > The > only reason I bother is in the hopes that it'll play some part in > preventing some of the lurkers from getting sucked in by the flurry of > informed-sounding but demonstrably wrong arguments which continue to > come from those folks. Roy, it is demonstrably wrong to try to use standing wave current phase to measure the delay through a coil. Anyone, including you, who says it is a valid procedure is either ignorant or trying to hoodwink the lurkers. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223280 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <3bFZf.703615$qk4.163958@bgtnsc05-news.ops.worldnet.att.net> Message-ID: Date: Sat, 08 Apr 2006 03:32:46 GMT Gene Fuller wrote: > I thought you denounced and denied this "concept" earlier today. Guess you misunderstood. A coil can replace 30 degrees of an antenna but it won't use the same amount of wire as 30 degrees of wire. What I said is that an inductor is more efficient than linear loading. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223281 of rec.radio.amateur.antenna From: Bob Subject: Re: Fiber Glass (shell) vs Metal References: <1144345851.115512.302060@z34g2000cwc.googlegroups.com> Message-ID: Date: Sat, 08 Apr 2006 03:43:34 GMT This will not answer your question but it is amusing. This guy claims his SS replacement top section for fiberglass antennas gives you 2dB gain and a lot of other BS. See: http://cgi.ebay.com/BASE-ANTENNA-UPGRADE-REALLY-WORKS_W0QQitemZ9709206755QQcategoryZ1501QQssPageNameZWDVWQQrdZ1QQcmdZViewItem “PRINCIPLE EXPLANATION... THIS UNIT IS A STAINLESS STEEL TOP SECTION THAT SCREWS INTO THE TOP SECTION OF YOUR EXISTING FIBERGLASS BASE ANTENNA, AND IT IS A PROVEN FACT STEEL ANTENNAS OUT PREFORM FIBERGLASS IT ALSO HAS A METAL HELIX COIL TO INCREASE RECIEVE .. THIS UNIT HAS A LOAD IN IT VERSES YOUR TOP SECTION THAT DOESNT HAVE A LOAD THIS INCREASES TRANSMIT POWER BY DRAWING POWER TO THE TOP LOAD....” Ooh, don’t question him, he’s a broadcast engineer! Ha! Bob Myles Byrne wrote: > Been looking for a used 2 mtr ant. - was reading some comments about > Fiber Glass and Lightning - Someone said "Fiber Glass to lightning is > like a trailer park to a tornado" - "It's all metal on the inside" - > So, is there something to the comment ? > Article: 223282 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> <123e1b1ntsbm27e@corp.supernews.com> <123e7bvrpae5c16@corp.supernews.com> Message-ID: Date: Sat, 08 Apr 2006 03:43:51 GMT David G. Nagel wrote: > evidently Cecil doesn't. It wasn't me who started this thread. If we have one amp of DC current flowing one direction and one amp of DC current flowing the other direction, which direction is the sum of those currents flowing? If we have one amp of forward RF current and one amp of reflected RF current, which direction is the sum of those currents flowing? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223283 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> Message-ID: Date: Sat, 08 Apr 2006 03:54:32 GMT Cecil Moore wrote: > w8ji@akorn.net wrote: > >> So what exactly is the importance of this current YOU are talking >> about? > > > All the diversionary BS trimmed from your posting. Bottom line, > the equation for standing wave current is: > > I(x,t) = Io*cos(kx)*cos(wt) > > The equation for traveling wave current is: > > I(x,t) = Io*cos(ks+wt) > > Since you obviously don't comprehend the difference, please > dust off your old math book and take a look. > > In case you need a graphics reference for those two equations, > you can find it at: http://www.qsl.net/w5dxp/travstnd.GIF > > You will find the two above currents are virtually opposites > of each other. > > In particular, standing wave current phase CANNOT be used to > determine the phase shift through a wire or through a coil > because its phase never changes in a 1/4WL monopole. > > I can hardly say it better than Gene Fuller who said: > Regarding the cos(kz)*cos(wt) term in a standing wave: > >> Gene Fuller, W4SZ wrote: >> >>> In a standing wave antenna problem, such as the one you describe, >>> there is no remaining phase information. Any specific phase >>> characteristics of the traveling waves died out when the startup >>> transients died out. >>> >>> Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen >>> again. >>> >>> The only "phase" remaining is the cos (kz) term, which is really an >>> amplitude description, not a phase. > > > Please tell us what it is about Gene's posting that you don't > understand. You know, Cecil, a pulse train also satisfies the wave equation. Why are you married to sinusoidal waves? Haven't you ever seen ghosts on a tv picture? What do those Ghosts represent? 73, Tom Donaly, KA6RUH Article: 223284 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> <123e1b1ntsbm27e@corp.supernews.com> Message-ID: Date: Sat, 08 Apr 2006 04:03:36 GMT Reg Edwards wrote: > "David G. Nagel" wrote > >>I have completely lost track of what the object of the exercise is. >> > > ======================================= > > I gave up trying just after the thread began. > > What put me off was "current across the coil" when everybody knows it > should be "current through the coil". > > It is VOLTS which appear ACROSS coils. > ---- > Reg. > > They also like to talk about "current drops" when they mean the difference in current amplitude at two different points. 73, Tom Donaly, KA6RUH Article: 223285 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Current across the antenna loading coil - from scratch Date: Fri, 07 Apr 2006 23:04:39 -0500 Message-ID: <123edj2nda7oe1@corp.supernews.com> References: <44329c0a_2@newsfeed.slurp.net> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> <123e1b1ntsbm27e@corp.supernews.com> <123e7bvrpae5c16@corp.supernews.com> Cecil Moore wrote: > David G. Nagel wrote: > >> evidently Cecil doesn't. > > > It wasn't me who started this thread. > > If we have one amp of DC current flowing one direction and > one amp of DC current flowing the other direction, which > direction is the sum of those currents flowing? > > If we have one amp of forward RF current and one amp of > reflected RF current, which direction is the sum of those > currents flowing? I was taught that under these circumstances DC and RF work differently. Yes your DC net current is zero. Your new RF current is one amp in each direction. Dave WD9BDZ Article: 223286 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Fiber Glass (shell) vs Metal Date: Fri, 07 Apr 2006 23:07:44 -0500 Message-ID: <123edoqa7b1ag2c@corp.supernews.com> References: <1144345851.115512.302060@z34g2000cwc.googlegroups.com> Bob wrote: > This will not answer your question but it is amusing. This guy claims > his SS replacement top section for fiberglass antennas gives you 2dB > gain and a lot of other BS. See: > http://cgi.ebay.com/BASE-ANTENNA-UPGRADE-REALLY-WORKS_W0QQitemZ9709206755QQcategoryZ1501QQssPageNameZWDVWQQrdZ1QQcmdZViewItem > > “PRINCIPLE EXPLANATION... THIS UNIT IS A STAINLESS STEEL TOP SECTION > THAT SCREWS INTO THE TOP SECTION OF YOUR EXISTING FIBERGLASS BASE > ANTENNA, AND IT IS A PROVEN FACT STEEL ANTENNAS OUT PREFORM FIBERGLASS > IT ALSO HAS A METAL HELIX COIL TO INCREASE RECIEVE .. THIS UNIT HAS A > LOAD IN IT VERSES YOUR TOP SECTION THAT DOESNT HAVE A LOAD THIS > INCREASES TRANSMIT POWER BY DRAWING POWER TO THE TOP LOAD....” > Ooh, don’t question him, he’s a broadcast engineer! Ha! > Bob > > > Myles Byrne wrote: > >> Been looking for a used 2 mtr ant. - was reading some comments about >> Fiber Glass and Lightning - Someone said "Fiber Glass to lightning is >> like a trailer park to a tornado" - "It's all metal on the inside" - >> So, is there something to the comment ? >> Since fiberglass is an insulator and stainless steel is a conductor I would say that he is 100% correct in his statement that the ss antenna will function better. :^) Dave N Article: 223287 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1144360350.476305.270240@u72g2000cwu.googlegroups.com> Subject: Re: VSWR AND AUTOMATIC TUNING Message-ID: Date: Fri, 7 Apr 2006 22:04:32 -0700 "Dave" wrote in message news:m6CdnWMUI7dgNajZnZ2dnUVZ_vGdnZ2d@comcast.com... > Big Nose wrote: > > > If a transceiver has an in built automatic antenna tuning and matching > > unit, is there any point in measuring the VSWR as a way of ascertaining > > its performance? > > NOPE! The VSWR in the line = The VSWR in the line = The VSWR in the > line = The VSWR in the line. The internal tuner does absolutely nothing > [NOTHING] to the VSWR in the line. > > The internal tuner will make the radio 'happy' within it's tuning range, > but it does NOTHING about the VSWR in the line! > > > > > > Obviously this would be measured with a thru line meter which would be > > placed in the feeder system. However, I have been thinking and it > > would appear that the tuning and matching unit would become part of the > > antennas impedance (its late and I hope that makes sense). > > > > The reason I ask is because I am trying to find out how well certain > > transceivers will perform with antennas which are designed for > > different systems. > > > Agree. But, whether you're doing your testing or operating afterward, there's usually some value in knowing the VSWR in the line. It may only serve to clue you to a problem -- and that's info worth having. I'm depending on the slightly risky assumption that most tuners you test will be able to match to a less-than-ideal antenna system with high VSWR in the feedline -- one that's not putting much power into the air. I had a USN antenna experience with an improperly-modified shipboard HF XMIT antenna. The Radiomen said it was hard to tune to it, the reflected power was always high and they never seemed able to "get out on it" (meaning poor reception reports from the distant end). When we put the antenna right, all their problems went away. Article: 223288 of rec.radio.amateur.antenna From: "Sal M. Onella" References: Subject: Re: How get RF through a sealed window? Message-ID: Date: Fri, 7 Apr 2006 22:19:11 -0700 wrote in message news:e13e9u$q3u@unix1.cc.ksu.edu... > I gave a presentation on "How Ham Radio Can Help You in an Emergency" > to 70 Emergency Management types last week, and the windows in the > building which hosted the meeting were NOT open-able (so I "made do" > with an inside VHF antenna and didn't even try to demonstrate HF). > > But in emergency/expedient situations, it would be really handy if one > could pass at HF, say, 100 watts of RF energy through a window (I > visualize some foil strips and an inductor or two to "tune out" the > capacitance) to an external antenna. > > I've been told that the April, 1989, issue of Ham Radio magazine carried > an article "Easy antenna access for urban apartment dwellers" (for 15 > meters) by Bryan Bergeron, NU1N, starting on page 18. > > I'd sure like to read that article; can anyone send me a copy? > -- > --Myron A. Calhoun. > Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge > PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 > NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) I have drilled a hole in a window frame and passed a piece of RG-58 through it. A 2M rig in my den is that way right now. It's easier to justify doing it to your own home than to a place you're visiting Article: 223289 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> Message-ID: Date: Sat, 08 Apr 2006 11:53:46 GMT Tom Donaly wrote: > You know, Cecil, a pulse train also satisfies the wave equation. > Why are you married to sinusoidal waves? Haven't you ever seen > ghosts on a tv picture? What do those Ghosts represent? If one doesn't understand sinusoidal waves, one doesn't have a ghost of a chance of understanding a pulse train. Trying to introduce a pulse train before understanding sinusoidal values is just muddying the waters. In a closed system, such as a source, transmission line, and receiver, ghosting represents reflected waves. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223290 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> <123e1b1ntsbm27e@corp.supernews.com> Message-ID: <2ANZf.13677$tN3.2395@newssvr27.news.prodigy.net> Date: Sat, 08 Apr 2006 11:58:54 GMT Tom Donaly wrote: > They also like to talk about "current drops" when they mean the > difference in current amplitude at two different points. For an EM wave in a lossy environment, the attenuation factor applies equally to the E-field and H-field, i.e. equally to voltage and current. Both "drop" at the same rate. The transmission line voltage equation contains that attenuation factor and the current equation is simply the voltage equation divided by the characteristic impedance. In a lossy transmission line, the H-field and E-field "drop" at the same rate since their ratio is fixed by the characteristic impedance. One more proof that EM waves are NOT lumped circuit voltages and currents. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223291 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426104.970207.48000@t31g2000cwb.googlegroups.com> <1144434415.541456.187410@z34g2000cwc.googlegroups.com> <1144445920.345719.251460@u72g2000cwu.googlegroups.com> <123e1b1ntsbm27e@corp.supernews.com> <123e7bvrpae5c16@corp.supernews.com> <123edj2nda7oe1@corp.supernews.com> Message-ID: Date: Sat, 08 Apr 2006 12:09:44 GMT David G. Nagel wrote: > Cecil Moore wrote: >> If we have one amp of forward RF current and one amp of >> reflected RF current, which direction is the sum of those >> currents flowing? > > I was taught that under these circumstances DC and RF work differently. > Yes your DC net current is zero. Your new RF current is one amp in each > direction. Yes, that is true, but EZNEC doesn't report the two separate currents. EZNEC reports the phasor sum of those two currents in magnitude and phase. So the question still remains: In which direction is the total current reported by EZNEC flowing? What does the unchanging phase really mean? EZNEC says that, referenced to the source phase, the phase of the phasor sum of the forward and reflected currents is UNCHANGING. It makes no sense to pick a direction of flow for the sum of two equal currents flowing in opposite directions. Standing wave current doesn't flow in the commonly accepted meaning of "flow". Standing wave current just stands there. I received the following email from a physics professor: "As for the standing waves, they really aren't independent creatures. They're an artifact - a construct which happens to look like the superposition of fields which surround the antenna. But the fields which superpose look like the traveling waves. The traveling waves really tell the story." -- 73, Cecil http://www.qsl.net/w5dxp Article: 223292 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> Message-ID: Date: Sat, 08 Apr 2006 12:20:53 GMT Dave wrote: > ... when really you are all saying the same thing. Unfortunately, we are not all saying the same thing. W7EL and W8JI are saying that using standing wave current phase to make a phase shift measurement is a valid approach. They keep reporting their results of using such an approach as if it were a valid thing to do. When those useless phase measurements are discarded, the technical picture becomes a lot clearer. I, and others, are saying that using a signal with unchanging phase will not and cannot tell one anything about any phase shift. There is no phase information contained in the standing wave phase. All of the phase information is contained in the standing wave magnitude. I'm building a web page about this subject. The initial graphic is at: http://www.qsl.net/w5dxp/travstnd.GIF Note that for a standing wave current, the only thing changing with length is magnitude. The flat phase line of the standing wave current is completely useless for making phase measurements. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223293 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: Feeding 2 VHF Yagis from one coax? References: Message-ID: Date: Sat, 08 Apr 2006 08:34:06 -0500 Hi Scott No doubt others will give you much better info than I. The gamma macth feed is irrelevent. If you have a resistive 50 ohm load for each antenna at its operating frequency it makes the maths of using tuned coax lengths a little easier. I would have to sit down and think about it a bit deeper but on the surface it looks like; Use a 1/4, 3/4, 5/4 etc wavelength of coax on 2M to attach the 6M antenna to the T piece. The logic is that the lowish impedance of the 6M antenna on 2M will be transposed to a high impedance at the T piece, the net result being little effect to feeding the 2M antenna. Do the reverse when feeding the 2M antenna. Problem - There is a relatively close harmonic relationship between 6M and 2M. ie a 1/4 wavelength on 6M is close to a 3/4 wavelength on 2M. If you think about it you will note that any 6M length will also be a 2M length! You cant actually get away from the problem! This feeding technique is only really usable when there isnt a 3:1, 5:1 etc frequency relationship. You are welcome to a spare coaxial relay I have! I dont however have spare N connectors. If you want it pls email me direct. Cheers Bob W5/VK2YQA East Texas Scott wrote: > > > I have a temporary tower set up with a 6M yagi on it. I'd like to add a > 2M yagi. Is it possible to feed the two antennas with one feedline > similar to feeding multiple HF antennas with one feedline? > Article: 223294 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> Message-ID: Date: Sat, 08 Apr 2006 14:30:46 GMT w8ji@akorn.net wrote: I had this example at the bottom of my posting but you seem to ignore such. So I am moving it to the top of the posting. If you ignore it now, at least everyone will know you couldn't possibly have missed it. You are in a room with a 50 ohm transmission line routed through a hole in one side of the room, across the room, and through a hole in the other side of the room. You don't know which is the source end of the line. A directional wattmeter reads 200 watts forward power and 200 watts reflected power but you don't know which direction is forward. Here's a diagram: 200W--> 2 amps--> hole-------------------50 ohm coax-------------------hole <--200W <--2 amps Which direction is the standing wave current flowing? If you knew forward current was moving left to right which direction would the standing wave current be flowing? > That's not true at all Dave. Most of us know that current is current. Too bad EZNEC disagrees with you as seen in the graphic at: http://www.qsl.net/w5dxp/travstnd.GIF The traveling wave current is virtually the opposite of the standing wave current as can be seen by their different equations. There is no phase information in the standing wave current phase. Yet that is exactly the phase W7EL used to try to measure the delay/phase shift through a coil. DC current is different from AC current. That's why the DC or AC designations are necessary. RF forward current is different from RF standing wave current. That's why the different designations are necessary. > It really only flows one direction at any instant of time. Or not at all at a standing wave current node. Too bad we are talking RMS values here which is what EZNEC reports. I'll ask the question of you: If one amp of RF current is flowing in one direction and one amp of RF current is flowing in the opposite direction, which direction does the phasor sum of those two currents flow? > We can > indeed consider systems as having current that flows two directions at > one instant of time, but the results of that better agree with the > actual real current that flows only in one direction at any instant of > time or they are wrong. The phase of standing wave current is unchanging. It doesn't "flow" in the commonly accepted sense of the word. As Hecht says in "Optics": "This is the equation for a STANDING or STATIONARY WAVE, as opposed to a traveling wave. Its profile does not move through space; it is clearly not of the form Func(x +/- vt)." [Standing wave phase] "doesn't rotate at all, and the resultant wave it represents doesn't progress through space - its a standing wave." If standing wave light doesn't move through space, then standing wave RF also doesn't move through a wire. > (I assume we all > know current ... does not "drop", ...) EM current does indeed drop exactly like EM voltage drops both according to the attenuation factor. Just one more proof that EM waves are not lumped circuit currents. The only difference in the equation for transmission line voltage and current is the voltage gets divided by the characteristic impedance which is usually a resistive constant. > I think the basic problem is Cecil wants to used some definition of > current that does not allow models to be freely exchanged and does not > produce results that match real world systems. It always has to match. > We can't have different results unless someone has an error. Exactly correct and the reason for the different results is your error. In any conflict between the distributed network model and the lumped circuit model, the distributed network model wins every time since it is a superset of the lumped circuit model. > This has gone on for perhaps three years now. It is really up to Cecil > and Yuri to let it go, since they are the ones who seem to disagree > with measurements and accepted theory. On the contrary, it is up to you and others to correct your misconceptions about standing wave current. Your "accepted theory" has holes in it that I could drive my GMC pickup through. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223295 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <3bFZf.703615$qk4.163958@bgtnsc05-news.ops.worldnet.att.net> Message-ID: Date: Sat, 08 Apr 2006 14:36:59 GMT Cecil Moore wrote: > Gene Fuller wrote: > >> I thought you denounced and denied this "concept" earlier today. > > > Guess you misunderstood. A coil can replace 30 degrees of > an antenna but it won't use the same amount of wire as > 30 degrees of wire. What I said is that an inductor is > more efficient than linear loading. Cecil, I am feeling dizzy. I am quite comfortable with my understanding of the entire problem, but I am seriously confused about your position. Nobody has ever talked about efficiency or the length of wire needed. The issue has always been replacing "degrees of antenna". I have captured a few excerpts from April 7. 73, Gene W4SZ Excerpt follow: 9:03 am -- From Cecil K7ITM wrote: > Another 'speriment occured to me, for those who think the coil current > MUST be different at the two ends by the amount corresponding to the > antenna section it replaces: To the best of my knowledge, nobody believes that. The coil is much more efficient at the loading function than is the straight wire from which it is made. That's why inductive loading is more efficient than fractal antennas or other types of linear loading. -- 73, Cecil http://www.qsl.net/w5dxp 9:24 am -- From Yuri [excerpt] Now you move that coil say half way up the must, to higher impedance point at the antenna, and that coil now, in order to maintain the "match" has to have higher impedance, more turns and will exhibit MORE current drop across it, while replacing THE SAME NUMBER OF "missing" DEGREES AT THE RADIATOR. Assuming that our goal is to stay with the same physical length of the whip (which we do) and maintaining 90 degrees of resonant radiator. So the radiator stays 50 degrees ()+50, 10+40, 20+30, 30+20, 40 + 10) long and coil replaces the same "missing" 40 degrees. [emphasis was in the original message] 9:44 am -- From Cecil Roy Lewallen wrote: > Of course loading coils can be expressed in electrical degrees. But extrapolating this to mean that a loading coil has the same properties as an antenna with the same number of "degrees" has no justification. I haven't heard anybody make that assertion in years. Coils occupy whatever number of degrees that they occupy. 8:49 pm -- From Cecil [excerpt] Example: The phase shift from 30% to 60% in the traveling wave antenna is taken from the tabular data as 54.2-27.6 = 26.6 degrees. The phase information is in the *phase* in a traveling wave. For the standing wave current, the situation is completely different. The phase measured between any two current probes will always be zero. The phase of a standing wave current is useless for measuring phase shift. The way to extract the phase information is to measure the *amplitude* at two points and then calculate the phase shift by taking the arc-cos of the normalized amplitude. Example: The phase shift from 30% to 60% in the standing wave antenna is arc-cos(0.8843) - arc-cos(0.5840) = 26.5 degrees. The phase information is in the *amplitude* in a standing wave. Thus in both antennas, the phase shift in 30 percent of the wire is about 27 degrees. (90*.3 = 27) If we had a coil installed in that 30 degrees of the antenna instead of a wire, the same concepts would apply. Article: 223296 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> Message-ID: Date: Sat, 08 Apr 2006 14:37:24 GMT Dave wrote: > admit it cecil, > while you may be correct, using a different set of terminology than most of > the people in here has done nothing but add to the confusion factor in many > of this long drawn out threads. I have a limited technical library. I wish my RF references spelled out everything as well as "Optics", by Hecht, but mine don't. Light and RF are the same kind of EM waves, just at different frequencies. Hecht's material is certainly relevant to RF waves. And I make every effort to translate the technical jargon from one field to the other as best I know how. Hecht presents the best treatment of superposition, interference, and standing waves that I have ever seen. I wish I had an RF reference book as well written as "Optics". -- 73, Cecil http://www.qsl.net/w5dxp Article: 223297 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <3bFZf.703615$qk4.163958@bgtnsc05-news.ops.worldnet.att.net> Message-ID: Date: Sat, 08 Apr 2006 14:51:21 GMT Gene Fuller wrote: > I am feeling dizzy. I am quite comfortable with my understanding of the > entire problem, but I am seriously confused about your position. Nobody > has ever talked about efficiency or the length of wire needed. The issue > has always been replacing "degrees of antenna". I have captured a few > excerpts from April 7. What you quoted from me is my reporting of what EZNEC says about standing wave current Vs traveling wave current at: http://www.qsl.net/w5dxp/travstnd.GIG The 'x' axis for both conditions is just a piece of 1/4WL wire. One can calculate the phase shift in any section of wire in two ways: 1. For traveling waves, the phase shift is given by the graph of the phase (red line). The magnitude (blue line) contains no phase information. 2. For standing waves, the phase shift is given by taking the arc-cosine of the magnitude (blue line). The phase (red line) contains no phase information. Before we talk about replacing a piece of wire with a coil, do you understand the above graphic and concepts? You seemed to understand when you posted: Regarding the cos(kz)*cos(wt) term in a standing wave: Gene Fuller, W4SZ wrote: > In a standing wave antenna problem, such as the one you describe, > there is no remaining phase information. Any specific phase > characteristics of the traveling waves died out when the startup > transients died out. > > Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be > seen again. > > The only "phase" remaining is the cos (kz) term, which is really > an amplitude description, not a phase. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223298 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> Message-ID: <0mRZf.9357$4L1.8786@newssvr11.news.prodigy.com> Date: Sat, 08 Apr 2006 16:17:00 GMT John Popelish wrote: > This is the pattern the standing wave function describes. The current > at every point has one of two phases, which are 180 degrees from each > other. > > Is this how you see it? Yes, now which direction is that current flowing? If the source were known to be to the left, would that change your answer? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223299 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <3bFZf.703615$qk4.163958@bgtnsc05-news.ops.worldnet.att.net> <4eydnTjNN9U9RKrZRVn-qQ@adelphia.com> Message-ID: Date: Sat, 08 Apr 2006 16:21:12 GMT John Popelish wrote: > Cecil Moore wrote: >> http://www.qsl.net/w5dxp/travstnd.GIF > Agreed, with one exception. > There is a phase reversal each time you pass through a node, ... You are correct if two sides of a node exist in the system. But since the context was my above 1/4WL wire, there is no "passing through a node". I was limiting my statements in context to a 1/4WL long conductor. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223300 of rec.radio.amateur.antenna From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Feeding 2 VHF Yagis from one coax? Message-ID: References: Date: Sat, 08 Apr 2006 16:44:51 GMT On Sat, 08 Apr 2006 11:02:06 +0000, Scott wrote: >I have a temporary tower set up with a 6M yagi on it. I'd like to add a >2M yagi. Is it possible to feed the two antennas with one feedline >similar to feeding multiple HF antennas with one feedline? > > > >Coax from Shack RG-8 RG-8 >=========================T============2M Yagi > I > I RG-8 > I > 6M Yagi > >So basically, I would add a T connector at the 6M Yagi and run another >piece of RG-8 from the T to the 2M Yagi (the T connector would have a >male PL-259 on one port connected directly to the 6M Yagi, the other 2 >ports are female UHF and one would be connected to coax from shack and >the other would have the jumper to the 2M antenna). Now the $64K >question...should the run of RG-8 from the T to the 2M be a certain >length, such as 1/4 or 1/2 Wavelength at one of the bands and if so >which band? i.e., 1/2 wavelength at 6M or 1/4 wavelength at 2M, etc. >Both antennas use a gamma match as the feed, so the short section of >coax seems like it might be perceived as a open-ended stub attached to >the 6M antenna??? This is for high speed meteor scatter, so I'm not >overly concerned if the antenna patterns get a bit screwed up... > >Scott >N0EDV What you need is called a Diplexor. Diplexors can be implemented in many ways (using coax sections s only one). Their goal is to keep the signal on one path seperated from another. However they introduce small measurable losses and that may not suit your scatter work. I've built and used diplexors for 145/437 (sats) use to deal with the two antennas one coax connection of some deal band radios. As to patterns, if the antennas are seperated enough there would be little effect. Myself I prefer two coax as the losses are lowest. Second best is coax relays at both ends (you still incur connector losses) . Third best is Diplexor as there are losses through a diplexor and isolation limits. Thats the short version. Allison Allison Article: 223301 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <0mRZf.9357$4L1.8786@newssvr11.news.prodigy.com> Message-ID: Date: Sat, 08 Apr 2006 18:02:49 GMT John Popelish wrote: > See all those arrows of various length representing current direction > and magnitude? Why do you ask me about something after erasing my answer? As is my custom, I erase everything I agree with. >> If the source were known to be to the left, would that change >> your answer? > > For a pure standing wave, there is effectively a source at each end, so > this question is meaningless. Exactly! Now try to tell that to W8JI and W7EL who attempt to assign a direction of flow to standing wave current and use its phase to determine the phase shift through a wire or coil. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223302 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <3bFZf.703615$qk4.163958@bgtnsc05-news.ops.worldnet.att.net> <4eydnTjNN9U9RKrZRVn-qQ@adelphia.com> Message-ID: Date: Sat, 08 Apr 2006 18:04:36 GMT John Popelish wrote: > So, add some transmission line to the system so a node's location is > measurable inside the system. By the way, in case you didn't notice, I > am agreeing with you, and elaborating on what you are saying. I know you are agreeing with me. The only disagreement you and I have ever had was over my poor choice of words. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223303 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Gamma. Before somebody tells me. References: <18KdnZLoy_I0iqrZnZ2dnUVZ8qOdnZ2d@bt.com> Message-ID: Date: Sat, 08 Apr 2006 18:06:09 GMT Reg Edwards wrote: > - - - - and perhaps I should add that I was well aquainted with the > behaviour of transmission lines well before Chipman wrote his book. He wrote his book almost 40 years ago, Reg. Do you know how old that makes you? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223304 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <0mRZf.9357$4L1.8786@newssvr11.news.prodigy.com> Message-ID: Date: Sat, 08 Apr 2006 18:08:37 GMT Richard Clark wrote: > I would, of course, task any/everyone to find any point along the line > where the SWR meter does not exhibit current flow for this > configuration. :-) That's easy, Richard. The current pickup in the SWR meter will read zero at a standing wave current node. It's a good thing that an SWR meter is not 100% dependent upon a current flow reading, eh? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223305 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> Message-ID: <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> Date: Sat, 08 Apr 2006 19:52:35 GMT w8ji@akorn.net wrote: > Cecil Moore wrote: > >> 200W--> 2 amps--> >>hole-------------------50 ohm coax-------------------hole >> <--200W <--2 amps >> >>Which direction is the standing wave current flowing? > > What are you calling "standing wave current flow"? Describe or define > it. The same standing wave current that you and W7EL used to make your current measurements on standing wave antennas. > Are you actually saying charges flow two directions at the same time > and place in any given snapshot of time? Water waves flow two directions at the same time using the same water molecules. EM waves flow two directions at the same time using the same carriers. Waves in a rope travel two directions at the same time using the same molecules. It is a common physical occurrence. Hint: The carriers of the waves are NOT the same thing as the waves. > The current we would measure at any place with a current indicator and > the phase of that current IS the actual current flow. What direction is that current flowing when its phase is not changing relative to the source phase? This is a key question. > It is impossible to have different currents at each end of the inductor > without having displacement currents, or what Reg calls "radial current > flow". We have different currents at each end of a wire quite often without having displacement currents. Does having zero amps and one point and one amp 1/4WL away mean there's displacement current in a transmission line? When you figure out the answer to that one, you will understand why the coil can have negligible displacement current and still have zero amps at one end and one amp at the other end, just like the wire or transmission line. Source--------------a-/////////-b------------------------------- Measured current at 'a' is zero amps. Measured current at 'b' is one amp. Where is the current at 'b' coming from? Certainly NOT >from displacement currents. > Why are you complicating your life with something that seems to be > giving you the wrong answer? Actually, I am complicating your life with something that gives the correct answer. If you will fix your misconceptions about standing wave current, everything else should be just fine. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223306 of rec.radio.amateur.antenna From: "AK" Subject: Velocity Factor (VP) for RG8X? Message-ID: Date: Sat, 08 Apr 2006 20:15:38 GMT Is 78% the correct velocity factor for RG8X coax? Article: 223307 of rec.radio.amateur.antenna From: "AK" References: Subject: Re: Velocity Factor (VP) for RG8X? Message-ID: Date: Sat, 08 Apr 2006 20:20:26 GMT Thanks Dave. The only Belden catalog info I could find on-line didn't list the VP. Is there a link for full Belden info you could give me? AK Article: 223308 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Velocity Factor (VP) for RG8X? Date: Sat, 08 Apr 2006 14:41:43 -0700 Message-ID: <123gbgoripn6t14@corp.supernews.com> References: My experience is that the velocity factor of foam dielectric cable like RG8X varies considerably from batch to batch and manufacturer to manufacturer. Apparently they have poor control over the foam density in the manufacturing process. For any application where it really matters, you really have to measure it for the particular piece of cable you'll be using. Roy Lewallen, W7EL AK wrote: > Is 78% the correct velocity factor for RG8X coax? > > Article: 223309 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Sat, 8 Apr 2006 17:37:20 -0500 Message-ID: <20545-44383B20-52@storefull-3253.bay.webtv.net> References: <8kdg32h9havm34fg03ssvbuiqc784q7nge@4ax.com> Richard Clark wrote: "No current, no SWR." That exact spot producing an SWR induced voltage cancellation must also have double the voltage of either the forward or reverse wave. Voltage maxima are concurrent with current minima. Your SWR meter needs to be able to give a good indication at any spot in the line including all maxima and minima. Best regards, Richard Harrison, KB5WZI Article: 223310 of rec.radio.amateur.antenna From: John Ferrell Subject: Ground elevated radials? Message-ID: Date: Sun, 09 Apr 2006 01:20:02 GMT I am experimenting with insulated radials on a vertical antenna. They are insulated wires on top of the ground. I have modeled it with EZNEC but I cannot model the center junction connected to ground because a one inch wire is too short for a segment. It seems to me that the center of the radials should be grounded for lightning protection and that it will have no effect on the antenna performance. Comments please? John Ferrell W8CCW Article: 223311 of rec.radio.amateur.antenna Date: Sat, 08 Apr 2006 20:37:31 -0500 From: Tom Ring Subject: Re: Please explain side lobe statement References: <1144517308.519584.87760@e56g2000cwe.googlegroups.com> <70uf32ddjbdkk660da5oj50r82en9c7cg1@4ax.com> Message-ID: <4438655b$0$1015$39cecf19@news.twtelecom.net> Richard Clark wrote: > On 8 Apr 2006 10:28:28 -0700, "Ron J" wrote: > > >>If a >>side lobe is a minor lobe, then why is it undesirable to have side lobe >>levels less than -20 dB? Thanks! > > > Hi Ron, > > If it were one side lobe, that would be great. If it is several dozen > minor side lobes, then that is entirely another matter. The antenna > design is devoting too much power in this aggregate. > > 73's > Richard Clark, KB7QHC As someone who does a lot of V/UHF antenna design, I'd say that -20 is fine, and less than -20 is generally better if it doesn't screw up the whole pattern, which it seldom does. The aggregate of a lot of -20 is an average of less than -20 across the included angles. For EME, which is pickier than HF, it's fine. I'm not sure what Richard could be talking about. Now if you want a 6 meter contest antenna for use in the midwest, you do not want very low sidelobes, but that's a different story. Tom K0TAR Article: 223312 of rec.radio.amateur.antenna Date: Sat, 08 Apr 2006 20:59:44 -0500 From: Tom Ring Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> Message-ID: <44386a91$0$1013$39cecf19@news.twtelecom.net> w8ji@akorn.net wrote: > Answer the question Cecil, how can we have charge movement over a small > length of conductor (in terms of the wavelength) in two directions at > the same time, or a drift velocity in two directions at once? > > 73 Tom > Tom Cecil and Co. are not interested in real physics, math, or engineering. They have made up their own. As I said to Roy, you may as well give up. Tom K0TAR Article: 223313 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Ground elevated radials? Date: Sat, 08 Apr 2006 19:00:33 -0700 Message-ID: <123gqm2par5ela8@corp.supernews.com> References: John Ferrell wrote: > I am experimenting with insulated radials on a vertical antenna. > They are insulated wires on top of the ground. > I have modeled it with EZNEC but I cannot model the center junction > connected to ground because a one inch wire is too short for a > segment. You can't model a connection to ground except with the MININEC ground type, and that ground type isn't suitable when the model contains low horizontal wires as in a radial system. Therefore, there's no way in EZNEC to model a connection between a low radial system and ground. Any "connection" between the model radials and ground is solely by field coupling, not by ohmic contact. See The Modeling Ground chapter in the Building The Model section of the EZNEC manual for more information. >. . . Roy Lewallen, W7EL Article: 223314 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Please explain side lobe statement Message-ID: References: <1144517308.519584.87760@e56g2000cwe.googlegroups.com> Date: Sun, 09 Apr 2006 02:09:32 GMT On 8 Apr 2006 10:28:28 -0700, "Ron J" wrote: >Hello, I have Balanis' Antenna Theory 3rd Edition. I read on page 31 at >the very last sentence that "Side lobe levels of -20 dB or smaller are >usually not desirable in most applications." > >Why? On the same paragraph it states that "minor lobes represent >radiation in undesired directions, and they should be minimized." If a >side lobe is a minor lobe, then why is it undesirable to have side lobe >levels less than -20 dB? Thanks! Another possible explanation is that if the main lobe is pointed in a direction with low ambient noise (eg quiet sky), the last thing you want to capture is significant power from hot earth (or other high temperature sources) via minor lobes. Owen -- Article: 223315 of rec.radio.amateur.antenna From: Allisonnospam@nouce.bellatlantic.net Subject: Re: Please explain side lobe statement Message-ID: <83rg32lto230rjjser7ciq9i9j4h43b3n8@4ax.com> References: <1144517308.519584.87760@e56g2000cwe.googlegroups.com> Date: Sun, 09 Apr 2006 02:11:00 GMT On 8 Apr 2006 10:28:28 -0700, "Ron J" wrote: >Hello, I have Balanis' Antenna Theory 3rd Edition. I read on page 31 at >the very last sentence that "Side lobe levels of -20 dB or smaller are >usually not desirable in most applications." > >Why? On the same paragraph it states that "minor lobes represent >radiation in undesired directions, and they should be minimized." If a >side lobe is a minor lobe, then why is it undesirable to have side lobe >levels less than -20 dB? Thanks! Side lobes represent energy not directed in the desired direction and therefor a represent robbed gain. the more lobes and the greater aggragate power in each the greater gain loss. In a different perspective there are interfereing signals, those that you do not want to hear or represent noise. Again sidelobes are a deteriment. Allison Article: 223316 of rec.radio.amateur.antenna Subject: Re: Velocity Factor (VP) for RG8X? From: Ed References: Message-ID: Date: 09 Apr 2006 02:23:27 GMT > i have a paper catalog, don't know about on-line links for them. > All the info in your paper catalog is available online at belden.com . All the original poster has to do is click on " Catalog " , then the " e-catalog " and then type in his cable type, ( RG8X) in the search window. Belden will then display the one type of RG8X cable they make, their number 9258. If one then clicks on this number, the complete specs will be displayed. Just scroll down the specs and one will find the velocity factor of Belden's RG8X is 82%. http://bwccat.belden.com/ecat/jsp/Index.jsp?&P1=undefined&P2 =undefined&P3=undefined&P4=undefined&P5=undefined&P6=undefined Ed K7AAT Article: 223317 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <0mRZf.9357$4L1.8786@newssvr11.news.prodigy.com> <44385301.4040506@adelphia.net> <1144546697.683464.23350@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 02:24:38 GMT w8ji@akorn.net wrote: > Roger D Johnson wrote: > >>Richard is wrong too! There are electrostatic meter movements. >> >>73, Roger > > > > Roger is wrong too, and Richard is not. > > Electrostatic indicators don't measure current or charge movement, they > measure voltage or charge displacement. > > But what I really want to know is how Cecil can have current flowing > both directions at the same instant of time in a single point of single > conductor, can dismiss displacement currents as trivial things that can > be ignored when they are required to define the most important aspects > of transmission or antenna behavior, and say the very thing that is > used to measure current suddenly doesn't measure his imaginary two-way > reflected and forward current's vector sum. > > That's what is really important, especially in light of the fact Cecil > is quick to play superior. > > Anyone who is really superior should be able to walk us through the > physics of two-way current and tell us why dosplacement currents don't > matter, and explain his magical transmission lines and antennas without > displacement current in a way that we all understand. > > 73 Tom > Cecil can't prove that charge can move in two opposite directions at once. No one can. It's impossible. He's always had problems with superposition, believing the constituents of a standing wave have more reality than the wave itself. 73, Tom Donaly, KA6RUH Article: 223318 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 02:44:46 GMT w8ji@akorn.net wrote: > Current is by definition is the flow of charge. And two equal EM waves flowing in opposite directions in the same wire use the same charge carriers. > By definition and by physics, we cannot have charges flowing two > directions at once at one point. A charge carrier cannot be moving in two directions at the same time. Two currents can certainly exist in opposite directions at the same time. That's what forward current and reflected current is. If you want to deny the existence of forward and reflected current, be my guest. > This is precisely the current we would measure with a current meter > sampling the magnetic field, it is the current we would measure > sampling radiation, and it is the current that would determine phase of > the radiation or induction field. Yes, but if it's phase is unchanging, which direction is it flowing? When the forward current and reflected current are of equal magnitudes, which direction is the phasor sum of those two currents flowing? > So please expain to use, even if we allow a conductor to have TWO > voltage gradients of opposite polarity over the same linear area of > conductor, why Cecil's Current is important. I have told you and W7EL about a dozen times before. One cannot use standing wave current phase to measure the phase shift through a wire or through a coil. Any such attempt will fail. Yet, that is what W7EL has reported as technical fact for about a year now. > Also, tell us how we can measure and prove in a repeatable test, the > two-way charge movement exists. Please stop implying something that isn't true. There is no two-way movement of single charge carriers. The current is NOT the same thing as the charge carriers. > Either you are creating diversionary conundrums, or you should be able > to explain how we can have charges moving past a point in a single > conductor that are moving both directions at one instant of time. Please cut the BS, Tom. Individual charge carriers don't move in both directions at the same time. The forward and reflected current waves move in both directions at the same time, unaware of each other's presence until they encounter an impedance discontinuity. It is obvious that you don't understand forward and reflected EM waves that can exist on a wire or even in free space. Please crack open a textbook on such. Ramo and Whinnery is a good reference. > The almost universal measurement method of current is magnetic. > Suddenly Cecil's Theory of Current renders universal measurement > methods obsolete! This is technical discussion and has absolutely nothing to do with you or me. > NEC uses current and voltage, not wave theory. You attempt to use an > engine that uses what you say we can use to prove we are wrong in using > current when there are standing waves! How do you explain EZNEC getting the same answer as the distributed network model at: http://www.qsl.net/w5dxp/travstnd.GIF? And while you are looking at that graph, please explain how the flat phase of the standing wave current can be used to measure phase through a wire or a coil. > Don't you think you should have understood the NEC engine used in the > program before using it to prove we cannot use current without > reflections? No. EZNEC agrees with the distributed network model. That's all I need to know about it. > Yes, absolutely. If you don't understand that, you'd better review > basic transmission lines and quit wasting everyone else's time giving > assignments. Exactly how does the displacement current to ground get outside of a coax line with no common-mode currents? > If we stopped that third path, the current would not change. Assume one amp of forward current and one amp of reflected current inside a piece of coax with no common-mode current. There's no third path to ground, yet the standing wave still exists, with current nodes and current loops. No third path to ground is required. > Answer the question Cecil, how can we have charge movement over a small > length of conductor (in terms of the wavelength) in two directions at > the same time, or a drift velocity in two directions at once? Your straw man is noted for all the world to see. A single charge carrier cannot move in two directions at the same time. But if you are denying that two EM waves can move in opposite directions at the same time, please just come right out and assert such. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223319 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 02:54:22 GMT John Popelish wrote: > At any point along the wire, and at any particular instant, whether as a > result of a standing or traveling wave, the current flows in the > direction of the wire, one way or the other. Such current does not have > a phase. It has a direction. In what direction is the RMS value of standing wave current flowing? > Those wave currents could not travel at nearly the speed of light > without the displacement currents. You and I are talking about different displacement currents. I'm talking about displacement current between a transmission line and the ground. We had previously been talking about displacement current between a loading coil and ground. > Then you are silly. You cannot describe the reason for wave velocity of > a conductor, transmission line or EM wave without displacement current. How does the displacement current get to ground when it's inside a shielded piece of coax with no common mode current on the outside braid? > Displacement current into the space around the node. How does the displacement current get past the coax shield to the outside world? > So please stop saying that displacement current is negligible in some > cases of traveling or standing waves. I'll even say it again. Inside a piece of shielded coax, the displacement current to ground is negligible yet the standing wave still exists. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223320 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <8kdg32h9havm34fg03ssvbuiqc784q7nge@4ax.com> <20545-44383B20-52@storefull-3253.bay.webtv.net> Message-ID: Date: Sun, 09 Apr 2006 02:55:44 GMT Richard Clark wrote: > Cecil Moore wrote: >>movement requires current - true but completely irrelevant. > > the myth of zero (0) current is busted. Please tell us about the position and velocity of each charge carrier, Richard. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223321 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <0mRZf.9357$4L1.8786@newssvr11.news.prodigy.com> <44385301.4040506@adelphia.net> <1144546697.683464.23350@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 03:10:26 GMT w8ji@akorn.net wrote: > But what I really want to know is how Cecil can have current flowing > both directions at the same instant of time in a single point of single > conductor, Forward and reflected EM waves, of course. Would you like to deny the existence of the two waves in the following equation? I(x,t) = I1*cos(kx+wt) + I2*cos(kx-wt) = Io*cos(kx)*cos(wt) Your lack of math skills is really getting to be embarassing. > ... can dismiss displacement currents as trivial things that can > be ignored when they are required to define the most important aspects > of transmission or antenna behavior, The only displacement currents that I said were secondary were the displacement currents to ground. In fact, in a shielded coax with no common mode current, displacement currents to ground are literally non-existent, yet the standing wave is still there inside the coax, with its nodes and loops. > ... and say the very thing that is > used to measure current suddenly doesn't measure his imaginary two-way > reflected and forward current's vector sum. I didn't say that. I said the standing wave phase cannot be used to measure the phase through a wire or a coil. That is readily apparent at: http://www.qsl.net/w5dxp/travstnd.GIF which you have been avoiding like the plague. The phase information is there in the standing wave current, but it is in the magnitude, not the phase. And you have to understand arc-cosine functions to be able to extract that phase information. > That's what is really important, especially in light of the fact Cecil > is quick to play superior. "Play superior"??? I'm not the arrogant one claiming to be so omniscient that he is never wrong. > Anyone who is really superior should be able to walk us through the > physics of two-way current ... Already done - please reference the above web page. All the data is exactly what EZNEC reported. I can lead you to water but I can't make you drink. If you will tell me what you don't understand about that web page, I will walk you through it, step by step. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223322 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <44386a91$0$1013$39cecf19@news.twtelecom.net> Message-ID: Date: Sun, 09 Apr 2006 03:12:25 GMT Tom Ring wrote: > w8ji@akorn.net wrote: >> Answer the question Cecil, how can we have charge movement over a small >> length of conductor (in terms of the wavelength) in two directions at >> the same time, or a drift velocity in two directions at once? >> > Cecil and Co. are not interested in real physics, math, or engineering. > They have made up their own. As I said to Roy, you may as well give up. Tom, I learned this stuff at Texas A&M in the 50's and it was decades old already, having been developed before I was born. Are you also willing to deny the existence of simultaneous forward and reflected EM waves? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223323 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <0mRZf.9357$4L1.8786@newssvr11.news.prodigy.com> <44385301.4040506@adelphia.net> <1144546697.683464.23350@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 03:17:59 GMT Tom Donaly wrote: > Cecil can't prove that charge can move in two opposite directions > at once. No one can. It's impossible. I agree with you. That topic is just another straw man from W8JI who is afraid to discuss EM waves moving in opposite directions at the same time. It's the EM waves that are moving in opposite directions at the same time, not the individual charge carriers. I have seen waves flowing in and flowing out at the same time in the Pacific Ocean. That doesn't mean that individual water molecules are moving in two opposite directions at once. Doesn't it mean you are losing the argument when you have to make up false stories about what I have said? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223324 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 03:31:59 GMT John Popelish wrote: >> If you want to deny the existence >> of forward and reflected current, be my guest. > > I deny it. There is only current at a point, just as there is only > water jiggling around under a wave on the ocean. Well, that means denial of the distributed network model. I've been waiting for that to happen. There's no point continuing an argument with someone who denies one of the cornerstones of EM wave theory. The distributed network model is accepted as a superset of the lumped circuit model and works when the lumped circuit model fails. The fact remains that standing wave current phase cannot be used to measure phase delay through a wire or through a coil. There is no phase information in standing wave current phase. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223325 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: <1f%Zf.118$1C4.14@fe09.lga> Date: Sat, 8 Apr 2006 23:31:51 -0400 Yuri wrote: > You agree that impedance along the radiator changes, being low at the > bottom, around tens of ohms, to being high at the top, around thousands of > ohms. )Tom replied: )I never said that. What do you mean by reactance? The X can be very )high but radiation resistance very low even near the open end. I really give up. What's the point. This is a typical example of Tom's response to technical argument or trying to go step by step. I am talking impedance, he "knows" I mean reactance. As I said, I get better response >from a brick wall. No wonder he duntgetit! Oh well! 73, Yuri, K3BU Article: 223326 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 03:37:49 GMT John Popelish wrote: > As far as the center conductor is concerned, the shield is the entire > universe. My point exactly! There is no third path to the outside world but the standing waves do exist inside the coax without it. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223327 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <0e1h325atvp6h4v26ds865ssktn1mqguim@4ax.com> Message-ID: Date: Sun, 09 Apr 2006 04:10:15 GMT Richard Clark wrote: > Cecil Moore wrote: >>There's no point continuing an argument > > The triumph of hope over experience. When one rejects the distributed network model, one must also reject Maxwell's equations. That seems like a religious act to me, not a technical choice. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223328 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 04:24:18 GMT John Popelish wrote: > But from the concept of a standing wave producing a current distribution > along the center conductor, the shield performs the function of ground. But that is irrelevant. The relevant fact is that there is NO third path to ground yet the standing waves exist anyway. That seems to indicate that the displacement current path to outside world ground is a secondary consideration compared to the superposing of the forward and reflected waves. If you are prepared to reject the distributed network model, are you also prepared to reject Maxwell's equations? Please note that rejection of the distributed network model leaves you with only a model known to fail under certain conditions. In any case, you haven't explained how the unchanging phase in a standing wave current can be used to measure phase shift through a wire or a coil. EZNEC says it is not a valid approach at: http://www.qsl.net/w5dxp/travstnd.GIF -- 73, Cecil http://www.qsl.net/w5dxp Article: 223329 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 04:44:32 GMT John Popelish wrote: > Cecil Moore wrote: >> If you want to deny the existence >> of forward and reflected current, be my guest. > > I deny it. There is only current at a point, just as there is only > water jiggling around under a wave on the ocean. There is only water juggling under two or more waves in the ocean. Anyone who has stood on the beach has observed ocean waves moving in opposite directions. Your assertion is easy to disprove. In the following example, the two sources have identical outputs and are phase locked. They are each equipped with circulators and 50 ohm loads. Source1---------------50 ohm coax------------------Source2 There is current flowing from Source1 heating up Source2's load resistor to the tune of I1^2*R. There is current flowing from Source2 heating up Source1's load resistor to the tune of I2^2*R. Your denial seems to be a denial of reality and more of a religious gut feeling than anything else. If you disconnect Source2 completely in the example above the conditions will be the same except Source1 will be dissipating its own power after a round trip to the open end and back by the energy waves. Incidentally, in the double source example above, which direction is the standing wave current flowing? How could its unchanging phase be used to measure the electrical length of the coax? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223330 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Velocity Factor (VP) for RG8X? References: <123gbgoripn6t14@corp.supernews.com> Message-ID: Date: Sun, 09 Apr 2006 04:46:28 GMT Reg Edwards wrote: > And the same applies to impedance Zo and attenuation. How much could the Z0 vary for "50 ohm" coax? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223331 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Sun, 09 Apr 2006 01:38:37 -0700 Message-ID: <123hi0fb91l66ab@corp.supernews.com> References: <443422d4_4@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> John Popelish wrote: > Cecil Moore wrote: >> John Popelish wrote: >> >>> At any point along the wire, and at any particular instant, whether >>> as a result of a standing or traveling wave, the current flows in the >>> direction of the wire, one way or the other. Such current does not >>> have a phase. It has a direction. >> >> >> In what direction is the RMS value of standing wave current flowing? > > That's easy. RMS current is an AC measurement of current along the > conductor. Over any integer number of cycles, the total movement of > charge is zero. The current spends half the time going one way, and > half the time going the other way. This applies to both standing and > traveling wave induced currents. The only current that describes a net > movement of charge in a single direction is DC. I see that Cecil is still having trouble with RMS, as well as with current. Otherwise he couldn't have come up with the nonsense question >> In what direction is the RMS value of standing wave current flowing? The RMS value of current doesn't flow. Charge flows, and current is the rate at which it flows. RMS is one way of expressing the magnitude of a time-varying current. In a steady state environment of pure sinusoidal waveforms, any current can be expressed as Ipk * cos(wt + phi) where Ipk is the peak value of the current, w (omega) is the rotational frequency, and phi is the phase angle. This gives you precisely the value of current at any instant in time, t. You can equally well express it as Irms * cos(wt + phi) where Irms is the RMS value of the current. Nothing is lost or gained by choosing one convention or the other, and using RMS doesn't require abandoning the time varying or phase information. (In EZNEC I chose to use RMS; NEC uses peak. They differ only by a constant factor of the square root of 2. Both report phase angle along with amplitude.) In either case, if you know or assume w, the current at any instant is known if you know phi and either Ipk or Irms. A point of clarification to John's posting: When a standing wave exists on a transmission line, the phase of the voltage or current is fixed (other than periodic phase reversals) with position only if the end of the line is open or short circuited. Otherwise, the phase of voltage and current will change with position. Roy Lewallen, W7EL Article: 223332 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Sun, 09 Apr 2006 01:47:40 -0700 Message-ID: <123hihe4ed6bm94@corp.supernews.com> References: <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <0mRZf.9357$4L1.8786@newssvr11.news.prodigy.com> <44385301.4040506@adelphia.net> <1144546697.683464.23350@v46g2000cwv.googlegroups.com> John Popelish wrote: > Cecil Moore wrote: >> w8ji@akorn.net wrote: >> >>> But what I really want to know is how Cecil can have current flowing >>> both directions at the same instant of time in a single point of single >>> conductor, >> >> >> Forward and reflected EM waves, of course. Would you like to deny >> the existence of the two waves in the following equation? >> >> I(x,t) = I1*cos(kx+wt) + I2*cos(kx-wt) = Io*cos(kx)*cos(wt) > > Those two expressions describe patterns of current over time and > location that produce current in each direction half the time (except at > nodes, where the current is zero). > > The amplitude of a current cycle is constant for the first one > (traveling wave), but the phase differs at different locations (by the > amount of kx). > > The amplitude of current cycle described by the second one (traveling > wave) varies with location, and the phase has only two possibilities > (one when cos(kx) is positive and 180 degrees different when cos(kx) is > negative). But in both cases, current at any point reverses twice a > cycle (cos(wt)) and charge goes nowhere over a cycle. I hope you guys realize that the stated equation is correct only when I1 = I2. Otherwise the solution is a sine or cosine function with a phase term. Roy Lewallen, W7EL Article: 223333 of rec.radio.amateur.antenna Date: Sun, 09 Apr 2006 03:31:56 -0600 From: BKR Subject: Re: Velocity Factor (VP) for RG8X? References: <123gbgoripn6t14@corp.supernews.com> Message-ID: <4438d481$1@nntp.zianet.com> Roy is right. You must meaure your cable to be sure. The stuff I have now calculates to .73 using a regular MFJ analyzer. Roy Lewallen wrote: > My experience is that the velocity factor of foam dielectric cable like > RG8X varies considerably from batch to batch and manufacturer to > manufacturer. Apparently they have poor control over the foam density in > the manufacturing process. For any application where it really matters, > you really have to measure it for the particular piece of cable you'll > be using. > > Roy Lewallen, W7EL > > AK wrote: > >> Is 78% the correct velocity factor for RG8X coax? >> Article: 223334 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <9pWdnYl3htToCqXZ4p2dnA@adelphia.com> Message-ID: Date: Sun, 09 Apr 2006 11:54:49 GMT John Popelish wrote: From an earlier posting: > For example, if we took a snapshot of the current, all along the line at the moment it peaked it might look like this:(length of arrow represents current magnitude, and head shows direction)(view in fixed width font) > > ....---> ---> --> -> <- <-- <--- <--- <-- <- -> -->...... > hole-------------------50 ohm coax-------------------hole x y There is a standing wave current node at 'x' and a standing wave current antinode (loop maximum) at 'y'. Let's say we installed coils at those two points ....---> ---> --> -> <- <-- <--- <--- <-- <- -> -->...... hole--------------/////----50 ohm coax----/////------hole x y Now we have current flowing into both ends of the coil located at 'x' and current flowing out of both ends of the coil at 'y'. How does the lumped circuit model handle that situation? Continuing with this posting: > Please don't be silly. Distributed networks have points. An infinite > number of them. Calculus is used to smoothly move through this infinity > of points. But at any particular point, current is defined as the rate > of movement of charge past that point. No argument, but that is instantaneous current and that is NOT the subject of this discussion. We are discussing the RMS phasor value of current used by W8JI and W7EL for their measurements and reported by EZNEC as in the graphic at: http://www.qsl.net/w5dxp/travstnd.GIF Please look at the standing wave current phase and tell us how that flat phase curve can be used to measure the phase shift in a wire or coil. The current reported by EZNEC and measured by W8JI and W7EL is *NOT* instantaneous current. It is RMS current. Instantaneous current is completely irrelevant to this discussion. >> I've been waiting for that to happen. There's no point >> continuing an argument with someone who denies one of >> the cornerstones of EM wave theory. > > So you deny that there are any points (where voltage can be defined or > that charge passes) in all distributed networks? > How strange. :-) You have your points confused. I was talking about a logical point. Here, let me translate for you. There's no *reason* to continue an argument with someone who denies one of the cornerstones of EM wave theory. John, is English your native language? For the record, I did NOT deny the existence any physical points!!! >> The fact remains that standing wave current phase cannot >> be used to measure phase delay through a wire or through >> a coil. There is no phase information in standing wave >> current phase. > > Yes. That fact remains. > It is a non sequitur in the above discussion, however. Whoa there, John, it is the entire reason for this discussion. W7EL used that standing wave current phase to try to measure phase shift through a coil. If there is no phase information in standing wave current phase, then his entire argument falls apart and he is back to square one with his flawed lumped circuit model. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223335 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 12:11:58 GMT John Popelish wrote: > To the center conductor, carrying the standing wave, the shield is the > outside world. If there is no shield, the outside world is the outside > world, as far as displacement current goes. Do you imagine this current > changes in some way other than magnitude and wave velocity when you wrap > a shield around a wire carrying a standing wave? No, that is your point, not mine. My point is that displacement current to real ground is non-existent outside of a coax shield (unless common mode current exists) and that it is usually a secondary effect if the coax shield doesn't exist. The primary reason for the variation in standing wave current along the line is the phasor sum of the forward and reflected wave phasors that are rotating in opposite directions. Do you understand phasor addition? 1 at zero + 1 at 180 deg = zero at a standing wave node? Displacement current to real ground doesn't cause that. > I am explaining distributed network theory to you. :-) How? By denying the existence of the individual H-fields in forward and reflected EM waves? Now, that's really funny. >> http://www.qsl.net/w5dxp/travstnd.GIF > > And I have agreed with that. Why do you keep bringing it up? Because that's the whole point of this discussion. If you agree with that, there is no reason to continue. I just don't care about instantaneous current, Brownian motion, or the exact location and velocity of every electron carrier. There's too much uncertainty involved. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223336 of rec.radio.amateur.antenna From: "AK" References: <123gbgoripn6t14@corp.supernews.com> Subject: Re: Velocity Factor (VP) for RG8X? Message-ID: Date: Sun, 09 Apr 2006 12:57:01 GMT All the info is very interesting. Thanks folks. Just want to make two 50-ohm 1/4-wave section lengths to transform the impedance of two linear-loaded 40 meter verticals (spaced 1/4 wave) from around 32 ohms to about 75 ohms, and then extend the cable from the "director" vertical element with another 1/4-wave with 75 ohm coax for the 90/90 phasing. Then I just "tee" the two feedpoints together to get one common feed point that's close to 50 ohms. Have done this previously with good results, and had a much better than expected match to the 50-ohm transmitter feedline. The last time I did this, I used fence wire that was staked into some flat farmland turf for the ground system. This time I will have to create an artificial ground plane or counterpoise, as the present mountain terrain does not lend itself well for creating a good low-loss real-ground system. Still have my old RG-11 matching section for the one 75-ohm coax 1/4-wave extension cable, but the two RG-8 sections are no longer around. So, thought I would use the smaller and cheaper RG8X this time. Maybe I won't. HI AK Article: 223337 of rec.radio.amateur.antenna From: ml Subject: vert distortion? Message-ID: Date: Sun, 09 Apr 2006 13:18:18 GMT hi i've noticed a few installations of say a 2m beam vertically mounted to a regular metal tv style mast >from looking at it, you have the mast(metal) going between 2 elements and longer than the elements so i was wondering as this is a common mounting style and method how bad is the beam pattern for rx and tx ? effected by the metal mast? it also got me thinking i've noteced some beams as in the above use a fiberglass boom while others use metal how does this effect patterns and efficiency both from a practical point of view and technically speaking ??? thanks Article: 223338 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> Message-ID: Date: Sun, 09 Apr 2006 15:40:09 GMT Cecil Moore wrote: > > I have been very careful to talk about the standing wave > current *at* the bottom and *at* the top of the coil, not > about the current *flowing* into the bottom of the coil > and out the top of the coil as you and W8JI have. Cecil, The wave is stationary. The current is not. It is as simple as that. Distinctions between *at* and *flowing* are meaningless. Current is what it is, and mere words don't change anything. You seem to be reduced to arguments about semantics, which is both good news and bad news. The good news is that there does not appear to be any disagreement about the physics. The bad news is that the argument will never end. 73, Gene W4SZ Article: 223339 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> Message-ID: Date: Sun, 09 Apr 2006 17:29:42 GMT Gene Fuller wrote: > The good news is that there does not appear to be any > disagreement about the physics. On the contrary, Gene. The disagreement is whether W7EL's use of standing wave current phase to try to determine phase shift through a coil was valid or not. That is the present point of disagreement. I have posted what you said many times but W7EL doesn't read my postings. So would you kindly point out to W7EL that there is no phase information in standing wave current phase? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223340 of rec.radio.amateur.antenna From: "GS" References: Subject: Re: Velocity Factor (VP) for RG8X? Message-ID: Date: Sun, 9 Apr 2006 13:17:58 -0400 Depending on the manufacturer the specs list VF from 0.72 to 0.81 in the Wirebook IV. Not to mention various manufacturing variations. 73's Guenther VE3CVS "AK" wrote in message news:KRUZf.88176$oL.627@attbi_s71... > Is 78% the correct velocity factor for RG8X coax? > Article: 223341 of rec.radio.amateur.antenna From: "Ken Bessler" Subject: 16 el coaxial colinear (2.4ghz) question Message-ID: Date: Sun, 9 Apr 2006 12:45:06 -0500 I built this antenna expecting better performance from my WiFi setup. Stock antennas are 1/2 wave verticals at the back of the router. New antenna is a 16 element coaxial collinear @32' agl. Total transmission system losses work out to 5.299db @2.412 ghz (includes feedline + N connectors). So, why does this antenna only have about (rough measurement) 1-3 db gain over the stock antenna? I was meticulous in my work, measuring the antenna parts with a digital caliper and checking the connections with a DVM along the way. Maybe my design is a fault? I built the antenna just like this: http://wireless.gumph.org/content/4/3/011-mini-wireless-antenna.html Except in my version, I've got 16 elements made from RG58. I also made 2 four element antennas for the back of my thinkpad and they seem to be working about twice as far as the antennas they replaced (inverted V's). Any ideas? 73's de Ken KG0WX - Kadiddlehopper #11808, Flying Pigs #-1055, Grid EM17io, Elecraft K2 #4913, XG2, 4SQRP Tenna Dipper, Heath GD-1B, MP-1(X)antenna Article: 223342 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> Message-ID: Date: Sun, 09 Apr 2006 17:48:36 GMT John Popelish wrote: > He seems to confuse energy in the wave traveling along a conductor with > the current it induces along that conductor, as it travels. It's not confusion, John. It is engineering convention. Every engineering reference book I have refers to current flow at one point or another. Most of them also refer to power flow. "Transmission Lines and Networks", by Walter C. Johnson even refers to "The Conservation of Power Principle". Since there is no such thing as an RF battery, we know exactly what Mr. Johnson meant. You are discussing the conventions used by physicists. Since this is basically an RF engineering convention newsgroup, you need to adjust your concepts accordingly or tell everyone that you are nit-picking based on the conventions from the field of pure physics. In the engineering world: Power companies generate power and transfer the power to the consumers over transmission lines. RF transmitters generate power which is transferred over the transmission line and radiated by the antenna. There is always a convention for placing an arrow on a wire to indicate direction of current flow, whether RMS AC or DC or RMS RF. The AC conventions are left over from the DC conventions. If you are trying to change those conventions, please say so. Food for thought: If an electron can pass through two different holes at the same time, can it also travel in two directions at the same time? Quantum physics says that is a possibility. > Is that because the result is not a pure standing wave (superposition of > two equal and oppositely traveling waves), but a superposition of a pair > of traveling oppositely traveling waves of different amplitudes? Yes, but the definition of a standing wave is that the two waves are of equal amplitudes. The wave you are describing is a hybrid wave containing both a traveling wave and a standing wave. Any real-world system contains hybrid waves in various ratios of traveling waves to standing waves. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223343 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <0e1h325atvp6h4v26ds865ssktn1mqguim@4ax.com> <3rdh32p0m2s28coh4bpgcmk37mdnmbas81@4ax.com> <1L7_f.68316$dW3.53978@newssvr21.news.prodigy.com> <9kdi32pem0ki8ti0040kb3dvf0504n37q7@4ax.com> Message-ID: <6Sb_f.9525$4L1.5698@newssvr11.news.prodigy.com> Date: Sun, 09 Apr 2006 17:53:07 GMT Richard Clark wrote: > Glad to hear you only use your own mind for that. > > So your religion practices Onanism? It means that if I decide to mentally masturbate, I'll use my own mind, thank you, not someone else's mind, as do a lot of the posters on this newsgroup. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223344 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <9pWdnYl3htToCqXZ4p2dnA@adelphia.com> Message-ID: Date: Sun, 09 Apr 2006 18:13:36 GMT John Popelish wrote: > If we assume the coil is an idealized lumped inductance with no stray > capacitance at all (not a real inductor) then it would have the same > instantaneous current at each end and that current would be zero, since > it has zero size. In other words it would fit entirely in the point > that holds the node. And such a coil is impossible in the real world so why even mention it? I want to hear about real world one foot long, 100 uH coils. > Real inductors with stray capacitance and imperfect magnetic coupling > for all parts of its internal current path, would have a phase shift in > the current at opposite ends, so they would have current at their ends > that was 180 degrees out of phase, if they were centered on the node > points. Yes, now please tell that to W8JI and W7EL. They are not listening to me. > I am not arguing for the validity of that measurement. Argue about it > with someone who is. That's my entire argument at the moment and W7EL is avoiding that argument like a plague. > In case you don't realize, there is more than one person out here, > responding to you. Please forgive me for not recognizing which of the ten individual junk yard dog "experts" is biting my ankles at any particular time. :-) > You remind me of a type of insanity where the sufferer thinks that > everything he is experiencing an organized illusion by a single > offending intelligence (you against the Matrix) bent on forcing him to > think that a lie is the truth, regardless of who or what he deals with. > Everyone he meets, every apparently random happenstance, the actions of > his dog and the weather, generally, are all a conspiracy to force him to > think that black is white, and he isn't going to fall for it. IMHO, hardly anyone here on r.r.a.a is interested in technical facts. Most "experts" think they already know everything, wouldn't recognize a differing concept if it bit them in the arse, and are more dedicated to preserving the pecking order than anything else. 'Course, I am only human and could, therefore, unlike the omniscient experts, be wrong about that. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223345 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> Message-ID: <4tc_f.9528$4L1.399@newssvr11.news.prodigy.com> Date: Sun, 09 Apr 2006 18:34:40 GMT John Popelish wrote: > I am making the point that if the displacement currents were > insignificant, outside a coax, then the speed of light for waves out > there would be infinite. And they are not, therefore those displacement > currents cannot be assumed to be insignificant. But I am not talking about displacement currents within the transmission line, as exists in free space. I am talking *solely* about the displacement currents to *earth ground*. I contend that those are often secondary effects as proven by the coax example. Just how much displacement current to "earth ground" is there for a coil located halfway between here and Alpha Centauri? > Exactly the opposite. I am explaining the distributed effect of the E > field along the wave. And completely ignoring the H-field? In the treatment of those fields, the only variation is Z0. For EM fields, there is no "across" and no "through". The difference between voltage and current essentially disappears except for their Z0 ratio. The equation for current in a transmission line is identical to the equation for voltage except for the Z0 term. Current "drops" are commonplace in lossy transmission lines. For instance, what is the current at the end of 200 feet of RG-58 terminated by a 50 ohm antenna used on 446 MHz when the source current is 2 amps? > You are avoiding the very facts that would allow you to make an air > tight argument for your beliefs about "the whole point of the > discussion". You somehow picture current as a continuous thing from one > end of a conductor to the other, when it carries a traveling energy > wave. This is a misconception. Maybe in the field of physics - not in the field of RF engineering. For any two current points, I can calculate a point in between. Sorry, but that's a characteristic of a *continuous* single-valued function and can be proven mathematically. I admit to being a EE/math major. I didn't take many pure physics courses so I am missing your point about me being able to prove anything additional. Maybe it will dawn on me after awhile. > What you don't get is, that the currents that each of those traveling > waves would have generated were localized, to begin with. I realize that is the physicist talking and it agrees with my earlier assertion that standing wave current doesn't flow. I guess I'm so dense that I need help in proving what you think I can prove with that information. Right now, I am apparently missing something, maybe because of too much California Merlot. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223346 of rec.radio.amateur.antenna From: "Jerry Martes" References: Subject: Re: 16 el coaxial colinear (2.4ghz) question Message-ID: Date: Sun, 09 Apr 2006 18:44:38 GMT "Richard Clark" wrote in message news:urii32h83hlu6u0bv6b04hmoku84so6c73@4ax.com... > On Sun, 9 Apr 2006 12:45:06 -0500, "Ken Bessler" > wrote: > >>New antenna is a 16 element coaxial collinear @32' agl. >>Total transmission system losses work out to 5.299db @2.412 >>ghz (includes feedline + N connectors). >> >>So, why does this antenna only have about (rough measurement) >>1-3 db gain over the stock antenna? I was meticulous in my work, >>measuring the antenna parts with a digital caliper and checking >>the connections with a DVM along the way. >> >>Maybe my design is a fault? > > Hi Ken, > > What did you compute as being the Velocity Factor for the shield being > covered with thick PVC? > > The problem with this modified Franklin Array is that you are cutting > for half-wave dimensions once, for two Velocity Factors along the same > length. Only one is going to be correct, and it is going to impact > the theoretical application of the other. > > You might want to try again using bare wire, twin lead fashion. > > 73's > Richard Clark, KB7QHC To Ken Hi Ken, I'd always take Richard's advice before mine. But, I wonder if you realize how difficult your task is. It is a very difficult project to develop the design of any array of radiators thats about 5 wavelengths long. And, it *is* a project, not just a matter of precise measuring and cutting. I'd think that 3 dB improvement over the antenna that was designed for optimum performance shows that you are doing something right. This project is a great learning opportunity for you. I'd suggest that you get a directional coupler and get some idea of the match of the array while it is being made longer. If you can manage to keep the VSWR under 2:1 with 6 or 8 elements, at your operating frequencies, you will be way ahead of me. Jerry KD6JDJ Article: 223347 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 18:52:08 GMT John Popelish wrote: > The definition of "local" is wavelength dependent. Since the reality in which we exist has been proven to be non-local in nature, I'm wondering what is your point? > Back to the RF case: Do you imagine that electrons from the source > reach the load? Maybe for DC. But depending upon the length of the transmission line, probably not for HF RF. Is that a rhetorical question? >> Someone needs to tell that to W7EL. I've tried to tell him but >> instead of thanking me, he 'ploinked' me. > > Perhaps he has lost interest in this thread. > Perhaps he is taking this topic personally. > Perhaps he enjoys yanking your chain. > Perhaps ... ... he is afraid of losing his "expert" status? > What does any of that have to do with our conversation? Everything. That's what this thread is all about. I will repeat: Can the standing wave current phase, with its unchanging phase, be used to measure the phase shift through a wire or coil? That's the admittedly narrow present topic. The answer is either 'yes' or 'no'. After we answer that narrow technical question, the discussion can procede. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223348 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <0e1h325atvp6h4v26ds865ssktn1mqguim@4ax.com> <3rdh32p0m2s28coh4bpgcmk37mdnmbas81@4ax.com> <1L7_f.68316$dW3.53978@newssvr21.news.prodigy.com> <9kdi32pem0ki8ti0040kb3dvf0504n37q7@4ax.com> <6Sb_f.9525$4L1.5698@newssvr11.news.prodigy.com> Message-ID: Date: Sun, 09 Apr 2006 18:57:55 GMT Richard Clark wrote: > Lot of bafflegab in that. I will take it to mean yes. Whatever way you choose to "take it" has absolutely no effect on any reality except your own personal reality existing only in your head. Enjoy! -- 73, Cecil http://www.qsl.net/w5dxp Article: 223349 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <9pWdnYl3htToCqXZ4p2dnA@adelphia.com> Message-ID: Date: Sun, 09 Apr 2006 19:10:46 GMT John Popelish wrote: >> Please forgive me for not recognizing which of the ten individual >> junk yard dog "experts" is biting my ankles at any particular time. :-) > > I am insulted that you include me in that derogatory characterization. > I have been polite, patient and respectful with you in this discussion. It wasn't derogatory, John. It was a paraphrasing of the old saying: "When one is up to one's ass in alligators, it's hard to remember that the original purpose was to drain the swamp." > But if you get back to physics, I will soon lose interest in your mind. I have no idea if "losing interest" is a good thing or a bad thing. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223350 of rec.radio.amateur.antenna From: "Ken Bessler" References: Subject: Re: 16 el coaxial colinear (2.4ghz) question Message-ID: Date: Sun, 9 Apr 2006 14:17:23 -0500 "Jerry Martes" wrote in message news:qCc_f.2174$wH1.1885@trnddc03... > > "Richard Clark" wrote in message > news:urii32h83hlu6u0bv6b04hmoku84so6c73@4ax.com... > > Hi Ken, > > > > What did you compute as being the Velocity Factor for the shield being > > covered with thick PVC? > > > > The problem with this modified Franklin Array is that you are cutting > > for half-wave dimensions once, for two Velocity Factors along the same > > length. Only one is going to be correct, and it is going to impact > > the theoretical application of the other. > > > > You might want to try again using bare wire, twin lead fashion. > > > > 73's > > Richard Clark, KB7QHC > > To Ken > > Hi Ken, I'd always take Richard's advice before mine. But, I wonder if > you realize how difficult your task is. It is a very difficult project to > develop the design of any array of radiators thats about 5 wavelengths long. > And, it *is* a project, not just a matter of precise measuring and cutting. > I'd think that 3 dB improvement over the antenna that was designed for > optimum performance shows that you are doing something right. > This project is a great learning opportunity for you. > > I'd suggest that you get a directional coupler and get some idea of the > match of the array while it is being made longer. If you can manage to keep > the VSWR under 2:1 with 6 or 8 elements, at your operating frequencies, you > will be way ahead of me. > > Jerry KD6JDJ > Thanks to both of you for your help. I took the antenna down and by- passed the 40' of LMR 400. Still, my Rssi with the OEM antennas was only 3db better on the big antenna. Thinking maybe the radome was an issue, I took it off and saw about another 2db improvement. I had fun building the antenna and I learned a lot. I just bought a pair of OEM high performance (9dbi gain) antennas off of eBay. Someone suggested running the router up my tower in an enclosure. Neat idea... Ken KG0WX Article: 223351 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <0e1h325atvp6h4v26ds865ssktn1mqguim@4ax.com> <3rdh32p0m2s28coh4bpgcmk37mdnmbas81@4ax.com> <1L7_f.68316$dW3.53978@newssvr21.news.prodigy.com> <9kdi32pem0ki8ti0040kb3dvf0504n37q7@4ax.com> <6Sb_f.9525$4L1.5698@newssvr11.news.prodigy.com> Message-ID: Date: Sun, 09 Apr 2006 19:39:27 GMT Richard Clark wrote: > Odd you chose to deviate from technical discussion to explain > "seeming" in terms of fornication and masturbation. You offer no > quantifiables, ... Suffice it to say that at my age, the quantifiables are not what they used to be. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 223352 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> Message-ID: Date: Sun, 09 Apr 2006 20:02:20 GMT John Popelish wrote: > Go back and ponder what I wrote. > Too much has been clipped for my elaboration to have any continuity. Sorry, I don't respond well to primrose paths. What keeps you >from simply stating your point? > It is a koan. Sorry, I don't respond well to "nonsensical questions". What keeps you from simply stating your point? Is it, if your point turns out to be wrong, you want me to take the heat? > If you have no interest in anything but butting heads with the people > who have disagreed with you, then, please stop responding to my posts. If you are into playing games, you are responding to the wrong person. Try W8JI or W7EL instead. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223353 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: 16 el coaxial colinear (2.4ghz) question References: Message-ID: <0g5og3-bsa.ln1@p400bob.personal.cox.net> Date: Sun, 09 Apr 2006 14:56:15 -0500 Hi Ken Further to my last about a narrow vertical beamwidth. http://members.cox.net/vk2yqa/pattern2.png Is a quick and rough modeling of a 16 el collinear. Note the half power beamwidth of only 4 degrees... Cheers Bob Article: 223354 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: 16 el coaxial colinear (2.4ghz) question References: Message-ID: <6m2og3-aqa.ln1@p400bob.personal.cox.net> Date: Sun, 09 Apr 2006 14:08:21 -0500 Hi Ken My first thought would be that a collinear with such a high gain would have a very narrow vertical beamwidth. ie a small angle off the vertical where mounted would have the remote site some dB down off the main lobe. The test for this will be to tilt the antenna back and forth whilst checking the RSL. Also keep in mind that reflections on 2.4GHz will cause a similar picket fence effect you might have heard on 2m/70cm. Your antenna could be mounted in a semi null. (I might try and model this some day and post you the results) Next idea is that with such a long colinear you are getting losses along the coax elements to the point where the upper element is radiating less than the lower ones. This will cause some skew in the radiation pattern. (upward tilt) TG213 would have been a better choice for this many elemets for this reason. Thirdly... Although RG58 is suppose to have a VF of 0.66 it does vary some from manufacturer to manufacturer. I havent bothered to work out how much difference it would make but would suspect that the longer the antenna (in elements) the worse it would become. Am thinking of making a Sterba curtain for WiFi. Looks easier than playing with bits of coax! Cheers Bob W5/VK2YQA East Texas Ken Bessler wrote: > I built this antenna expecting better performance from my WiFi > setup. Article: 223355 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <4tc_f.9528$4L1.399@newssvr11.news.prodigy.com> Message-ID: Date: Sun, 09 Apr 2006 20:05:53 GMT John Popelish wrote: > Cecil Moore wrote: >> For instance, what is the current at the end of 200 feet of RG-58 >> terminated by a 50 ohm antenna used on 446 MHz when the source >> current is 2 amps? > > Somewhat less then 2 amps. Does "somewhat" cover 24 dB of losses? :-) The point is that the current "drops" by exactly the same amount as the voltage. That's a characteristic of distributed networks as opposed to lumped circuits. In a Z0 RF environment, the current has to "drop" by exactly the same amount as the voltage to maintain the Z0 ratio. There are really no "across" and "through" concepts as exist in DC circuitry. >> I guess I'm so dense that I need help in proving what you think >> I can prove with that information. Right now, I am apparently >> missing something, maybe because of too much California Merlot. > > Sounds like something I might do, this afternoon. Which, helping or imbibing? :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 223356 of rec.radio.amateur.antenna From: "Ken Bessler" References: <0g5og3-bsa.ln1@p400bob.personal.cox.net> Subject: Re: 16 el coaxial colinear (2.4ghz) question - How 'bout this? Message-ID: Date: Sun, 9 Apr 2006 15:25:13 -0500 "Bob Bob" wrote in message news:0g5og3-bsa.ln1@p400bob.personal.cox.net... > Hi Ken > > Further to my last about a narrow vertical beamwidth. > > http://members.cox.net/vk2yqa/pattern2.png > > Is a quick and rough modeling of a 16 el collinear. Note the half power > beamwidth of only 4 degrees... > > Cheers Bob Wow - that's sharp! It explains why I lost the signal in my front yard. How about this version? http://martybugs.net/wireless/collinear.cgi I just built it out of a coat hanger, soldered to the old coax feedpoint from the last "experiment". It performs pretty good but I calculate 2.14db of losses in the line. Something my back of the set antennas don't have to deal with. What about expanding the above antenna? Ken KG0WX Article: 223357 of rec.radio.amateur.antenna From: "Peter O. Brackett" References: <7bcf32hmbefldctb9b7mdmh76bbplmnluo@4ax.com> Subject: Re: Gamma. Before somebody tells me. Message-ID: Date: Sun, 09 Apr 2006 20:27:03 GMT Gamma Fans: One area of practical interest for which Zo is not "real" occurs over [broad] ranges is in the area of application of the so-called "last mile" [for you Newbies that might be "first mile" (grin)] of POTS (Plain Old Telephone Service) twisted pair transmission lines to a variety of communications "last mile" communications systems. Over the frequency ranges of interest for telephone cable applications i.e. >from below 25Hz or so for some signalling and on up to several hundred kHz or even a few MHz for xDSL applications such as ISDN BA and HDSL, T1, etc..., the telephone twisted pair exhibits a Zo that varies all over the map! In this arena, complex Zo and highly variable Gamma is the norm, in this twisted pair media and for those kinds of applications, unfortunately for Mr. Smith Zo is NOT purely resistive. The Zo of twisted pair ranges rom very nearly purely capacitive impedance of several thousand kOhms at low frequencies to purely resistive near 100 Ohms at the higher ends. Analysis and design of systems that operate over this 5-6 decade range of frequencies must perforce use complex Zo! Smith's venerable chart is completely useless. Smith's Chart is only for "amateurs" who use transmission lines in very limited ways. The complex reflection coeficient in all of its' glory reigns supreme for those practical and realistic design and application scenarios. Thoughts, comments? -- Pete k1po Indialantic, FL. "Wes Stewart" wrote in message news:7bcf32hmbefldctb9b7mdmh76bbplmnluo@4ax.com... > On Sat, 08 Apr 2006 01:34:33 GMT, Cecil Moore > wrote: > >>Reg Edwards wrote: >>> But, believe it or not, under certain load conditions the reflection >>> coefficient Gamma can exceed unity. Indeed, at a sufficiently low >>> frequency, Gamma can approach 1+Sqrt(2) = 2.414 >> >>That agrees with Chipman who says it only occurs in lossy lines. > > But in theory, the line can have loss and this does not occur :-) > Article: 223358 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Sun, 9 Apr 2006 16:46:05 -0400 wrote in message news:1144583024.698268.212720@z34g2000cwc.googlegroups.com... > > Yuri Blanarovich wrote: >> Yuri wrote: >> > You agree that impedance along the radiator changes, being low at the >> > bottom, around tens of ohms, to being high at the top, around thousands >> > of >> > ohms. >> >> )Tom replied: >> )I never said that. What do you mean by reactance? The X can be very >> )high but radiation resistance very low even near the open end. >> >> I really give up. What's the point. This is a typical example of Tom's >> response to technical argument or trying to go step by step. I am talking >> impedance, he "knows" I mean reactance. As I said, I get better response >> from a brick wall. >> No wonder he duntgetit! Oh well! > > Yuri, > > Part of communicating is understanding the words the other person is > using. I'm only trying to understand what you intend the words you use > mean. > Please don't blame me for trying to sort out what you are saying. If > you mean "reactance", say "reactance" and not "impedance". If you mean > "through", say "through" and not "across". Really good one Tom! Why twist and dance? If you don't know what the impedance is please read 2005 ARRL Handbook: page 4.42 Impedance (re Inductance) and page 22.1 Impedance (re Antennas) If we measure current drop from one end of the the coil to the other, we see current drop across the coil. (You would love "through" because you can then "prove" that if it flows through it has to be the same, right?) > When you use "across", I guessed and thought you really meant "through" > or "at each end". > > When you used "impedance", I couldn't guess and figure out if you meant > the scalar impedance, vector impedance, resistance, reactance, or what. > It could mean too many things. I meant freakantance, just could not express it :-) Nice try! Keep on twisting. Before you didn't get it, now you don't want to get it. Let's back off one more giant step back to measurements. Show where W9UCW was "cheating" in his test setup, pictures and comments at http://www.k3bu.us/loadingcoils.htm where he shows clearly that RF current drops significantly across (through) the loading coil, just like it drops across (through) the resonant antenna (piece of wire or tubing) from max at the base, to zero at the tip. I venture to say that (most) everybody knows that impedance of such resonant radiator is low, about few ohms, at the base to thousands of ohms at the tip. If you don't know or get that, no point of discussing current magnitude at the ends of the loading coil. > > 73 Tom > 73 Yuri, K3BU Article: 223359 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <4tc_f.9528$4L1.399@newssvr11.news.prodigy.com> Message-ID: <9qe_f.57498$F_3.30487@newssvr29.news.prodigy.net> Date: Sun, 09 Apr 2006 20:48:05 GMT Cecil Moore wrote: > John Popelish wrote: > >> Cecil Moore wrote: >> >>> For instance, what is the current at the end of 200 feet of RG-58 >>> terminated by a 50 ohm antenna used on 446 MHz when the source >>> current is 2 amps? >> >> >> Somewhat less then 2 amps. > > > Does "somewhat" cover 24 dB of losses? :-) The point is that the > current "drops" by exactly the same amount as the voltage. That's > a characteristic of distributed networks as opposed to lumped > circuits. In a Z0 RF environment, the current has to "drop" by exactly > the same amount as the voltage to maintain the Z0 ratio. There are > really no "across" and "through" concepts as exist in DC circuitry. > >>> I guess I'm so dense that I need help in proving what you think >>> I can prove with that information. Right now, I am apparently >>> missing something, maybe because of too much California Merlot. >> >> >> Sounds like something I might do, this afternoon. > > > Which, helping or imbibing? :-) Merlot is what we Californians ship to out of state Republicans in hopes of poisoning them into not voting in the next election. 73, Tom Donaly, KA6RUH Article: 223360 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Gamma. Before somebody tells me. References: <7bcf32hmbefldctb9b7mdmh76bbplmnluo@4ax.com> Message-ID: Date: Sun, 09 Apr 2006 21:09:07 GMT Peter O. Brackett wrote: > Gamma Fans: > > One area of practical interest for which Zo is not "real" occurs over > [broad] ranges is in the area of application of the so-called "last mile" > [for you Newbies that might be "first mile" (grin)] of POTS (Plain Old > Telephone Service) twisted pair transmission lines to a variety of > communications "last mile" communications systems. > > Over the frequency ranges of interest for telephone cable applications i.e. > from below 25Hz or so for some signalling and on up to several hundred kHz > or even a few MHz for xDSL applications such as ISDN BA and HDSL, T1, > etc..., the telephone twisted pair exhibits a Zo that varies all over the > map! > > In this arena, complex Zo and highly variable Gamma is the norm, in this > twisted pair media and for those kinds of applications, unfortunately for > Mr. Smith Zo is NOT purely resistive. > > The Zo of twisted pair ranges rom very nearly purely capacitive impedance of > several thousand kOhms at low frequencies to purely resistive near 100 Ohms > at the higher ends. > > Analysis and design of systems that operate over this 5-6 decade range of > frequencies must perforce use complex Zo! > > Smith's venerable chart is completely useless. Smith's Chart is only for > "amateurs" who use transmission lines in very limited ways. > > The complex reflection coeficient in all of its' glory reigns supreme for > those practical and realistic design and application scenarios. > > Thoughts, comments? > > -- > Pete k1po > Indialantic, FL. > > > "Wes Stewart" wrote in message > news:7bcf32hmbefldctb9b7mdmh76bbplmnluo@4ax.com... > >>On Sat, 08 Apr 2006 01:34:33 GMT, Cecil Moore >>wrote: >> >> >>>Reg Edwards wrote: >>> >>>>But, believe it or not, under certain load conditions the reflection >>>>coefficient Gamma can exceed unity. Indeed, at a sufficiently low >>>>frequency, Gamma can approach 1+Sqrt(2) = 2.414 >>> >>>That agrees with Chipman who says it only occurs in lossy lines. >> >>But in theory, the line can have loss and this does not occur :-) >> > > > How are you, Peter? Is this some kind of religious controversy? I can't imagine hams having any use for twisted pair transmission lines, but maybe you can give your lines some fractal qualities, or show how current can flow four directions at the same time in the same place in them or the voltage at any given point on one of them must have 25 possible values simultaneously, or that the impedance on a typical line is proportional to the square root of Cecil's forearm. In fact, giving them any qualities that are impossible will endear them to the great post hog on this newsgroup and start a never ending thread. 73, Tom Donaly, KA6RUH Article: 223361 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Sun, 9 Apr 2006 16:22:23 -0500 Message-ID: <2025-44397B0F-519@storefull-3252.bay.webtv.net> References: Cecil, W5DXP wrote: "There is no phase information in standing wave current phase." Kraus and Terman agree with Cecil. Kraus writes on page 239 of his 1950 edition of "Antennas": "It is generally assumed that current distribution of an infinitesimally thin antenna (l/a=infinity) is sinusoidal, and that the phase is constant over a 1/2-wavelength interval, changing abruptly by 180-degrees between intervals." This agrees with Terman who writes on page 94 of his 1955 edition of "Electronic and Radio Engineering": "When the load impedance does not equal the characteristic impedance (as at the open-circuit at the standing-wave antenna tip), the phase relations are complicated by the presence of the reflected wave. The phase of the resulting voltage (or current) then oscillates about the phase of the voltage (or current) of the incident wave , as illustrated in Fig. 4-5.The phase shift under these conditions tends to be concentrated in regions where the voltage (or current) goes through a minimum;----." Pity the fool who argues with Kraus or Terman. Best regards, Richard Harrison, KB5WZI Article: 223362 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Sun, 09 Apr 2006 15:37:14 -0700 Message-ID: <123j34t8lqp37c5@corp.supernews.com> References: <443422d4_4@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> John Popelish wrote: > Roy Lewallen wrote: >> John Popelish wrote: >> >> A point of clarification to John's posting: >> >> When a standing wave exists on a transmission line, the phase of the >> voltage or current is fixed (other than periodic phase reversals) with >> position only if the end of the line is open or short circuited. >> Otherwise, the phase of voltage and current will change with position. > > Is that because the result is not a pure standing wave (superposition of > two equal and oppositely traveling waves), but a superposition of a pair > of traveling oppositely traveling waves of different amplitudes? Yes, but I wouldn't put it quite that way. I prefer to say that this is simply a special case of the more general result you get when you sum forward and reverse waves. Nothing magical or abrupt happens when the two traveling waves are equal in amplitude -- if they're slightly different, you get a little phase shift of the total current with position along the wire, the current minima aren't quite zero, and the spatial shape of the amplitude of the total current -- that is, the shape of the standing wave -- isn't quite sinusoidal. Making the amplitudes more and more different smoothly transitions the nature of the total current until in the special case of the reverse traveling wave being zero you have the distribution of a pure traveling wave. Roy Lewallen, W7EL Article: 223363 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <2JidnXYWTozFHKTZ4p2dnA@adelphia.com> Subject: Re: Counterpoise wire length Message-ID: Date: Sun, 9 Apr 2006 18:53:07 -0400 Counterpoise to what? You need to describe what are you trying "counterpoison". Yuri, K3BU "Harbin" wrote in message news:2JidnXYWTozFHKTZ4p2dnA@adelphia.com... > Counterpoise wire length. I've heard that it should be 1/4 wave, and then > again I've > heard it should be 1/2. Which is correct, or will they both work? > > -- > SeeYaa:) Harbin Osteen KG6URO > > This is YOUR future: > http://halturnershow.com/aztlan_caps.wmv > > - > Article: 223364 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Velocity Factor (VP) for RG8X? Date: Sun, 09 Apr 2006 16:00:48 -0700 Message-ID: <123j4h2b1t00a8f@corp.supernews.com> References: I have one piece, and it measures 0.745. Roy Lewallen, W7EL Article: 223365 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: 16 el coaxial colinear (2.4ghz) question - How 'bout this? References: <0g5og3-bsa.ln1@p400bob.personal.cox.net> Message-ID: Date: Sun, 09 Apr 2006 17:40:41 -0500 Hi Ken Note when I modeled the 16 element I did so as a series of dipoles fed in phase rather than use the coax/crossover design. I felt like checking your statement about being unable to receive in the front yard. At around 45 degrees down from the antenna the NEC2 output says that you'll get a lobe between 20 and 30dB down from an isotropic (or 35-45dB down from the max gain) I'll admit my near close in signal theory doesnt really exist but a path of 800m has about 106dB of loss. If you knock that back to 12 metres (6dB every time you halve) you have about 70dB path loss. If you then take a WAP kind of power level of around 10dBm the RX signal at 12m with a halve wave is going to be around (10-70-25) -85dBm. This kind of corelates with the lowest usable signal for WiFi! There ya go! I like the URL you sent as being more predictable/easier to construct that using bits of coax. Keep in mind that progressively longer and longer colinears are more and more critical to build and the construction method that is being used is not really optimal in the area of spacing between elements. You could probably pick a much better design. I think however that you need to sit back and consider what you are trying to achieve. Are you setting up a personal WiFi LAN for others to use or just for specific contacts? If you are wanting to work in one direction (or use a rotator) it might be more effective to use a corner reflector and maybe 4 elements in phase. This will be much less critical in construction. Remoting the WAP will make a lot of sense too as you'll lose the line loss! Comments? Cheers Bob Ken Bessler wrote: > > > Wow - that's sharp! It explains why I lost the signal in my front yard. > > How about this version? > > http://martybugs.net/wireless/collinear.cgi > > I just built it out of a coat hanger, soldered to the old coax > feedpoint from the last "experiment". It performs pretty good > but I calculate 2.14db of losses in the line. Something my > back of the set antennas don't have to deal with. > > What about expanding the above antenna? > > Ken KG0WX > > Article: 223366 of rec.radio.amateur.antenna Date: Sun, 09 Apr 2006 18:15:58 -0500 From: Tom Ring Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <123c2oranvatgf4@corp.supernews.com> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <44386a91$0$1013$39cecf19@news.twtelecom.net> Message-ID: <443995af$0$1012$39cecf19@news.twtelecom.net> Cecil Moore wrote: > Tom Ring wrote: > >> w8ji@akorn.net wrote: >> >>> Answer the question Cecil, how can we have charge movement over a small >>> length of conductor (in terms of the wavelength) in two directions at >>> the same time, or a drift velocity in two directions at once? >>> >> Cecil and Co. are not interested in real physics, math, or >> engineering. They have made up their own. As I said to Roy, you may >> as well give up. > > > Tom, I learned this stuff at Texas A&M in the 50's and it was > decades old already, having been developed before I was born. > Are you also willing to deny the existence of simultaneous > forward and reflected EM waves? Nope, but that's not what you're arguing about. tom K0TAR Article: 223367 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <4tc_f.9528$4L1.399@newssvr11.news.prodigy.com> <9qe_f.57498$F_3.30487@newssvr29.news.prodigy.net> Message-ID: Date: Sun, 09 Apr 2006 23:36:07 GMT Tom Donaly wrote: > Merlot is what we Californians ship to out of state Republicans > in hopes of poisoning them into not voting in the next election. What do you ship out to Libertarians? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223368 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Velocity Factor (VP) for RG8X? Message-ID: References: <123j4h2b1t00a8f@corp.supernews.com> Date: Sun, 09 Apr 2006 23:41:46 GMT On Sun, 09 Apr 2006 16:00:48 -0700, Roy Lewallen wrote: >I have one piece, and it measures 0.745. > This is a bit like the previous discussions on Buryflex! I read an interesting article on the 'net by NEC on a production system for foam dielectric coax for low microwave frequencies... it is clearly a greater challenge than extruding PE for solid dielectric. Reg's response is interesting, I draw the conclusion that a 'quick and dirty' confirmation of quality of a foam cable is whether its measured VF is close to spec, it is it off, so is the Zo likely to be off. Owen -- Article: 223369 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Gamma. Before somebody tells me. Message-ID: <9o6j321edov88om57p8dig083sm3i6bjgo@4ax.com> References: <7bcf32hmbefldctb9b7mdmh76bbplmnluo@4ax.com> <1l0j32dpg7i9o80444qb6nm591hpgab2lc@4ax.com> Date: Sun, 09 Apr 2006 23:42:56 GMT On Sun, 09 Apr 2006 16:35:30 -0700, Wes Stewart wrote: >On Sun, 09 Apr 2006 21:09:07 GMT, "Tom Donaly" > wrote: > >>Peter O. Brackett wrote: >> >>> Gamma Fans: >>> >>> One area of practical interest for which Zo is not "real" occurs over >>> [broad] ranges is in the area of application of the so-called "last mile" >>> [for you Newbies that might be "first mile" (grin)] of POTS (Plain Old >>> Telephone Service) twisted pair transmission lines to a variety of >>> communications "last mile" communications systems. >>> >>> Over the frequency ranges of interest for telephone cable applications i.e. >>> from below 25Hz or so for some signalling and on up to several hundred kHz >>> or even a few MHz for xDSL applications such as ISDN BA and HDSL, T1, >>> etc..., the telephone twisted pair exhibits a Zo that varies all over the >>> map! >>> >>> In this arena, complex Zo and highly variable Gamma is the norm, in this >>> twisted pair media and for those kinds of applications, unfortunately for >>> Mr. Smith Zo is NOT purely resistive. > >Aren't you supposed to normalize the chart to Zo? Nothing Mr. Smith >said required Zo to be resistive. > But most of the charts don't scale the area where the magnitude of the reflection coefficient is greater than 1. Owen -- Article: 223370 of rec.radio.amateur.antenna Date: Sun, 09 Apr 2006 18:45:50 -0500 From: Tom Ring Subject: Re: Please explain side lobe statement References: <1144517308.519584.87760@e56g2000cwe.googlegroups.com> <70uf32ddjbdkk660da5oj50r82en9c7cg1@4ax.com> <4438655b$0$1015$39cecf19@news.twtelecom.net> Message-ID: <44399cae$0$1004$39cecf19@news.twtelecom.net> Richard Clark wrote: > On Sat, 08 Apr 2006 20:37:31 -0500, Tom Ring > wrote: > > >>I'm not sure what Richard could be talking about. > > > Hi Tom, > > Compare a yagi to a rhomboid. > > 73's > Richard Clark, KB7QHC Point taken. They are tough to rotate, though. Also if you stack yagis properly, things get much better. tom K0TAR Article: 223371 of rec.radio.amateur.antenna From: "Ken Bessler" References: <0g5og3-bsa.ln1@p400bob.personal.cox.net> Subject: Re: 16 el coaxial colinear (2.4ghz) question - How 'bout this? Message-ID: <%3h_f.579$B42.454@dukeread05> Date: Sun, 9 Apr 2006 18:49:04 -0500 "Bob Bob" wrote in message news:a4fog3-f4b.ln1@p400bob.personal.cox.net... > Hi Ken > > Note when I modeled the 16 element I did so as a series of dipoles fed > in phase rather than use the coax/crossover design. > > I felt like checking your statement about being unable to receive in the > front yard. At around 45 degrees down from the antenna the NEC2 output > says that you'll get a lobe between 20 and 30dB down from an isotropic > (or 35-45dB down from the max gain) I'll admit my near close in signal > theory doesnt really exist but a path of 800m has about 106dB of loss. > If you knock that back to 12 metres (6dB every time you halve) you have > about 70dB path loss. If you then take a WAP kind of power level of > around 10dBm the RX signal at 12m with a halve wave is going to be > around (10-70-25) -85dBm. This kind of corelates with the lowest usable > signal for WiFi! There ya go! > > I like the URL you sent as being more predictable/easier to construct > that using bits of coax. Keep in mind that progressively longer and > longer colinears are more and more critical to build and the > construction method that is being used is not really optimal in the area > of spacing between elements. You could probably pick a much better > design. I think however that you need to sit back and consider what you > are trying to achieve. Are you setting up a personal WiFi LAN for others > to use or just for specific contacts? If you are wanting to work in one > direction (or use a rotator) it might be more effective to use a corner > reflector and maybe 4 elements in phase. This will be much less critical > in construction. Remoting the WAP will make a lot of sense too as > you'll lose the line loss! Comments? > > Cheers Bob > That's great info, Bob - btw my router puts out +20dbm and the background noise level in the receiver @ 2.422ghz is -97dbm +/- 2-3db.... As far as my purpose, I'm trying to get access when I go to a park to go /p on 40m. I want to be able to access the DX cluster & HF Pack users as well as check e-mail. I did a little research and the antennas I bought on eBay are 7dbi gain with, of course no feedline losses. No matter how much I crunch the numbers, I just can't find a more cost effective system. Ken KG0WX Article: 223372 of rec.radio.amateur.antenna Date: Sun, 09 Apr 2006 18:51:59 -0500 From: Tom Ring Subject: Re: Please explain side lobe statement References: <1144517308.519584.87760@e56g2000cwe.googlegroups.com> <70uf32ddjbdkk660da5oj50r82en9c7cg1@4ax.com> <4438655b$0$1015$39cecf19@news.twtelecom.net> Message-ID: <44399e20$0$1005$39cecf19@news.twtelecom.net> Richard Clark wrote: > On Sat, 08 Apr 2006 20:37:31 -0500, Tom Ring > wrote: > > >>I'm not sure what Richard could be talking about. > > > Hi Tom, > > Compare a yagi to a rhomboid. > > 73's > Richard Clark, KB7QHC And, as I said, for some, perhaps many, contesting situations, low side lobes are a good idea. On the east and west coasts, it's often good to have as much F/B and F/S as possible because of the population density and direction of it, while in the midwest the situation is quite different, with few stations scattered all over the map, and it's desirable to have sidelobes and rear lobes around -15 or so. tom K0TAR Article: 223373 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Velocity Factor (VP) for RG8X? Date: Sun, 09 Apr 2006 18:02:28 -0700 Message-ID: <123jbl8ccov1sbe@corp.supernews.com> References: <123j4h2b1t00a8f@corp.supernews.com> Owen Duffy wrote: > . . . > Reg's response is interesting, I draw the conclusion that a 'quick and > dirty' confirmation of quality of a foam cable is whether its measured > VF is close to spec, it is it off, so is the Zo likely to be off. I don't agree that this is a good test. The Z0 of cables with solid PE insulation varies considerably, and it's doubtful that the variation is due to variable dielectric constant of the solid insulation. So why should we assume that Z0 variation in foamed dielectric cable is due solely or mostly to the dielectric density? Roy Lewallen, W7EL Article: 223374 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Velocity Factor (VP) for RG8X? Message-ID: References: <123j4h2b1t00a8f@corp.supernews.com> <123jbl8ccov1sbe@corp.supernews.com> Date: Mon, 10 Apr 2006 01:52:25 GMT On Sun, 09 Apr 2006 18:02:28 -0700, Roy Lewallen wrote: >Owen Duffy wrote: >> . . . >> Reg's response is interesting, I draw the conclusion that a 'quick and >> dirty' confirmation of quality of a foam cable is whether its measured >> VF is close to spec, it is it off, so is the Zo likely to be off. > >I don't agree that this is a good test. The Z0 of cables with solid PE >insulation varies considerably, and it's doubtful that the variation is >due to variable dielectric constant of the solid insulation. So why >should we assume that Z0 variation in foamed dielectric cable is due >solely or mostly to the dielectric density? The thinking is more the case that the foam density / dielectric constant is apparently very hard to control, and in cheap cables with poor QA, a probably source of failure to meet spec. Owen -- Article: 223375 of rec.radio.amateur.antenna From: Bob Bob Subject: Re: 16 el coaxial colinear (2.4ghz) question - How 'bout this? References: <0g5og3-bsa.ln1@p400bob.personal.cox.net> <%3h_f.579$B42.454@dukeread05> Message-ID: Date: Sun, 09 Apr 2006 21:27:38 -0500 Hi Ken Well if you are going to a specific location (the park) you may as well use a directive antenna like a corner reflector/gridpack etc. In fact you could be real smart and use a 2m handheld and a low data rate link to swing the antenna in whatever direction you choose (eg packet talking to a home PC, PC connected to rotator. You could even make it as simple as a two state tone decoder for CW or CCW the antenna whilst watching the WiFi signal) There are some quite broad reflector based designs out there that give good gain on 2.4GHz. For example a 900x700mm gridpack will give you about 25dBi. I guess you are using one of the amateur radio 2.4GHz channels? You can use a higher EIRP than the normal WiFi is limited to. (from memory 30dBm EIRP is the legal max for unlicensed use) You do need to identify though. (A simple text based ping might be enough) I am surprised at the -97dBm sensitivity. The links I worked on in the past we used -87 for 11MB 802.11b predictions. I guess your figure would be at the lowest data rate and thus effective bandwidth. You can't beat Boltzmann! The Ethernet microwave data radios I work with nowadays need about 20-25dB s/n for a 50MB/sec channel that covers about 10MHz b/w. Thermal noise in 10MHz is about -103dBm so we need better than -83 for a good path. Our radios dont change speeds/bandwidth on the fly though. Interference will be your greatest enemy though... One of you other posters suggested remoting the router box to remove the cable loss problem. It is the place where most of your problems lie. Even moving it part the distance will help. You might also look at a better coax. We use to use LMR400 extensively. It was much cheaper than RG213 and lower loss as well. Oh and be careful with the WAP etc setup as regards "maximum distance". We had a problem early on where we left it at the default for a 10km path and the ACKs (or something) kept crashing and kept the speed down. The distance number introduces some kind of ACK delay.. Good luck! Cheers Bob VK2YQA Ken Bessler wrote: > > That's great info, Bob - btw my router puts out +20dbm and the > background noise level in the receiver @ 2.422ghz is -97dbm +/- > 2-3db.... Article: 223376 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Sun, 09 Apr 2006 20:16:07 -0700 Message-ID: <123jjfqq228vcdb@corp.supernews.com> References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <9pWdnYl3htToCqXZ4p2dnA@adelphia.com> John Popelish wrote: > > If we assume the coil is an idealized lumped inductance with no stray > capacitance at all (not a real inductor) then it would have the same > instantaneous current at each end and that current would be zero, since > it has zero size. In other words it would fit entirely in the point > that holds the node. > > Real inductors with stray capacitance and imperfect magnetic coupling > for all parts of its internal current path, would have a phase shift in > the current at opposite ends, so they would have current at their ends > that was 180 degrees out of phase, if they were centered on the node > points. For half of each cycle, current would be entering each end, and > for the other half of each cycle, current would be leaving each end. > Both those currents would detour out the sides f the inductor into > displacement current through the stray capacitance of the surface of the > inductor to its surroundings. > > I think (with very little actual knowledge of the software) this > conceptual model is how EZNEC handles current through a modeled inductor > and how it can have different currents at the inductor ends, without > being aware of whether those currents are driven by traveling or > standing waves. It is all based on current through inductor segments > and voltage across capacitive segments. If the segments are small > enough, it is a good approximation of a distributed solution. There are two ways of modeling an inductor in EZNEC. One is by using an inductive "load". This is a pure lumped inductance, which takes up zero physical space and whose currents are equal at its two terminals. It does not couple or react at all to its surroundings other than via its terminals, and its voltage-current characteristics are dictated by that of a pure inductance, v = L di/dt. For a number of reasons discussed many times here, this isn't a good model for many or most typical loading coils. The other way of modeling an inductor in EZNEC is by making it from conductors -- "wires" -- arranged in a polygonal helix. (EZNEC v. 4.0 provides an automated way to generate this structure.) These wires are treated exactly the same as all other wires in the model. As long as the turns aren't too close together (conservatively, closer than several wire diameters, but in practice good results are usually obtained with spacing as close as one diameter air space between wires), it does a very good job of calculating the inductor currents and radiation. (It's a little generous about loss if the turns are close because it doesn't account for proximity effect.) EZNEC calculates the total current by first calculating the self and mutual impedances of every segment in the model from a fundamental equation, then using Ohm's law to find the total current in each segment >from those impedances and the voltages from the user specified sources.(*) It's not aware of traveling or standing waves. The presence or absence of standing waves -- that is, a changing magnitude of current with position -- can be seen by viewing its output. Displacement current is a consequence of mutual coupling between segments -- in a dipole, the dominant coupling is to the other half of the dipole, and in a grounded monopole, to ground. However, each segment couples to every other, even on its own wire, and it's this coupling which brings about the current distribution that ultimately occurs. EZNEC deals only with total currents and makes no effort to detect, use, or break up total current into individual traveling waves. It isn't aware of whether currents are "driven by traveling or standing waves" if for no other reason that no currents are ever "driven by" traveling or standing waves. Voltage differences cause currents which can be described as traveling waves. When multiple traveling waves are summed to find a total current, the amplitude of the sinusoidal current varies with position along the line, and this envelope is called a "standing wave". A standing wave is simply a description of the magnitude distribution of the total current along a wire or transmission line. It doesn't drive or cause anything -- it's a description of an effect, not a cause. All the fuss about standing waves is a diversion which confuses the issue and deflects attention from the salient issues involved in understanding the topic under discussion. (*) This is a simplified explanation. For details, see Part I of the NEC-2 manual. Roy Lewallen, W7EL Article: 223377 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> <1144634798.546962.8210@u72g2000cwu.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Sun, 9 Apr 2006 23:27:09 -0400 This is freakin unbelievable. You think you are making fool of me and rest of us? You are not answering questions, nor engaging in the exchange. You keep pulling out crap, like first the current is equal, then "" I can change current difference at each end of the inductor all over the place depending on the design of the loading coil, with NO change in the loading coil position or antenna lengths." You are getting tangled in your own webs!!! Tell us what is wrong with W9UCW setup and results. Where did he screw up, what is wrong, and show what you have measured in THE SAME type of setup. Not freakin W8JI coils, not at the base, no weird frequency, not twist and dance. Just take 40m shorted vertical, make it resonant with DECENT coil like he has about 2/3 up the mast, stick the RF ammeters at both ends and give us the readings. You have the pictures, you should be able to replicate the setup. Then you tell us that the current is the same at both ends, show us the pictures and describe your setup, meters, frequency and results. This goes for the rest of the "gurus" that insist on the same. Then model the loading coil as a solenoid or loading stub of same inductance in EZNEC and show us what you get. Cecil did it, and the silence is deafening!!! Can you explain what is "wrong" with Cecil's examples? Looks like Belrose should get another pHDuuhh for starting all this misconception and misinformation in ham literature. Pathetic is that some of the "gurus" that should know better, are on the same bandwagon to la-la land. Stop crap and twist and dance, answer the freakin questions or say nothing. We are not idiots that you BS with "you don't know what I mean by impedance". So what happened to impedance? Now you know what it is, or is pink electron displacement capacitance current phasor phase mumbo jumbo? wrote in message news:1144634798.546962.8210@u72g2000cwu.googlegroups.com... > > Yuri Blanarovich wrote: >> Let's back off one more giant step back to measurements. Show where >> W9UCW >> was "cheating" in his test setup, pictures and comments at >> http://www.k3bu.us/loadingcoils.htm >> where he shows clearly that RF current drops significantly across >> (through) >> the loading coil, just like it drops across (through) the resonant >> antenna >> (piece of wire or tubing) from max at the base, to zero at the tip. > > Displacement currents in the inductor and the very high reactance of > the very short antenna above the coil explain current difference. > > Current cannot vanish Yuri. It has to have an alternative path. Have you heard of standing waves? > I can change current difference at each end of the inductor all over > the place depending on the design of the loading coil, with NO change > in the loading coil position or antenna lengths. That is the progress, first current can't change, now you can make it. > It is the theory you have, that the current is tied to the "missing > degrees", that is wrong. > > Without displacement currents there is no current difference at each > end of the coil, it is not caused by "missing degrees. It is caused by > the capacitance above the coil being very low and the capacitance of > the coil to the outside world being much larger. The current is not all > gone in the first few turns either. It is a series reactance/shunt > reactance problem. > > 73 Tom > PRICELESS!!!!! So WHAT IS THE CURRENT AT THE TOP OF THE RESONANT 90 deg (any) VERTICAL? Same as at the base, because "Current can not vanish Yuri"? You are jerking our chain or have a real problem. Suggestion: do some reading on impedance, resonance, standing waves, current and voltage distribution along the antennas, and look at the current curves in books and as produced by EZNEC. Looks like you have no clue how antennas work. You can have another "last word" that will "show" that you "know" what you are talking about. 73 Yuri Article: 223378 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Transforner Theory Date: Sun, 09 Apr 2006 20:29:33 -0700 Message-ID: <123jk90b36oii42@corp.supernews.com> References: <74ac6$44347c7f$45011502$11431@KNOLOGY.NET> <12390ho8oit9539@corp.supernews.com> <1239dl1litgdfc5@corp.supernews.com> <970b1$4435036d$45011502$7643@KNOLOGY.NET> It's been quite a few years now, so things might have changed. But some time back I learned a bit about the ferrite manufacturing process. It turns out that the green ceramic shrinks by something like 20 or 25 percent during the firing process, with poor control over the amount of shrinkage. The gaps in gapped pot cores, I found, were only nominally the specified gap width -- each pot core was individually ground to meet the Al specification, not some specification on air gap size. This isn't important in using them, but I found it interesting. What you get with an air gap in trade for effective permeability, is much greater independence of Al from the core characteristics (material permeability and physical size) and therefore much greater stability with regard to temperature and flux density, and much greater flux density capability. Roy Lewallen, W7EL Peter O. Brackett wrote: > Inductance core fans: > > [snip] >> PS. interesting how pot cores have very little inductance change with >> changing gausse. > [snip] > > Most, if not all, pot cores used for "precision" inductors and transformers > come in matched pairs with a very accurately ground narrow air gap between > the two center posts. The Al (or alpha from some mfgs) is accurately set by > the width of the air gap as ground during manufacture. The air gap also > forms a large part of the overall magnetic path (air having a much larger > reluctance than the ferrite). Such pot cores for precision inductors > usually have an adjustable slug (set with a non magnetic screwdriver) to > allow the finally assembled inductor to be set to an "exact" value. > > And so... pot cores intended for use in making precision inductors (as in > filters or delay equalizers) or precision transformer applications exhibit > little change in inductance over a wide range of conditions simply because > of the air gap. > > -- > Pete k1po > Indialantic By-the-Sea, FL > > Article: 223379 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1144360350.476305.270240@u72g2000cwu.googlegroups.com> Subject: Re: VSWR AND AUTOMATIC TUNING Message-ID: Date: Sun, 9 Apr 2006 21:03:51 -0700 "Richard Clark" wrote in message news:o3ne321qj2br52tp87t8l29i1a1n2tjkd9@4ax.com... > On Fri, 7 Apr 2006 22:04:32 -0700, "Sal M. Onella" > wrote: > > >I had a USN antenna experience with an improperly-modified shipboard HF XMIT > >antenna. The Radiomen said it was hard to > >tune to it, the reflected power was always high and they never seemed able > >to "get out on it" (meaning poor reception reports from the distant end). > > > >When we put the antenna right, all their problems went away. > > Hi OM, > > What was the problem, and what did you do to fix it? > > 73's > Richard Clark, KB7QHC The antenna was a trussed whip for 10-30 MHz. The truss frame was stabilized by four turnbuckles connected to the base through ceramic insulators. One of the RM's had bonded across the insulators. We were about to do a routine megger check when my partner spotted it. We couldn't believe our eyes. EMI bond straps are appropriate for a lot of things topside. That wasn't one of them. :-) "Sal" (John, KD6VKW; USN 1962 - 1982) PS: Radiomen are no more, per se. They and the Data Processing Technicians were rolled into a combined rating of Information Systems Technician - IT. Where it was once hard to find somebody in Radio Central who knew anything about RF, it is now twice as hard. For me, it's called Job Security, so I'm not _really_ complaining. Article: 223380 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <44329c0a_2@newsfeed.slurp.net> <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> <1144634798.546962.8210@u72g2000cwu.googlegroups.com> Message-ID: <7Pk_f.9884$4L1.3452@newssvr11.news.prodigy.com> Date: Mon, 10 Apr 2006 04:04:19 GMT w8ji@akorn.net wrote: > Current cannot vanish Yuri. It has to have an alternative path. Forward current is one amp at zero degrees. Reflected current is one amp at 180 degrees. That creates a standing wave current node where net current is zero. It has "vanished" due to superposition. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223381 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <9pWdnYl3htToCqXZ4p2dnA@adelphia.com> <123jjfqq228vcdb@corp.supernews.com> Message-ID: Date: Mon, 10 Apr 2006 04:11:54 GMT Roy Lewallen wrote: > EZNEC deals only with total currents and makes no effort to detect, use, > or break up total current into individual traveling waves. Then, without effort, EZNEC accurately reports the presence of traveling waves or standing waves as can be seen from the graph of the EZNEC results at: http://www.qsl.net/w5dxp/travstnd.GIF The graph on the left is for traveling wave current. Its magnitude is fixed and its phase varies with wire length. Traveling wave phase can be used to determine the phase shift through the wire (or through a coil). The graph on the right is for standing wave current. Its phase is fixed and its magnitude varies with wire length. Standing wave magnitude can be used to determine the phase shift through the wire (or through a coil) by taking the arc-cosine of the magnitude. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223382 of rec.radio.amateur.antenna From: "Sal M. Onella" References: Subject: Re: vert distortion? Message-ID: Date: Sun, 9 Apr 2006 21:37:17 -0700 "ml" wrote in message news:m-51EAB2.09181409042006@news.verizon.net... > hi > > > i've noticed a few installations of say a 2m beam vertically mounted to > a regular metal tv style mast > > from looking at it, you have the mast(metal) going between 2 elements > and longer than the elements > > so i was wondering as this is a common mounting style and method > > how bad is the beam pattern for rx and tx ? effected by the metal mast? > > > > it also got me thinking i've noteced some beams as in the above use a > fiberglass boom while others use metal > > how does this effect patterns and efficiency > > both from a practical point of view and technically speaking Here's a partial answer: I had a 2M copper pipe j-pole suspended vertically and well away from any other metal. I ran the coax through a switchable attenuator into a radio tuned to a local repeater with fairly steady chatter. I set the attenuator to put the radio deep into the noise -- a few dB away from Gone. Then , I took a length of mast, held it vertical and slowly approached the j-pole. I had to get within about one inch to affect the chatter. The direction from which I approached didn't seem to matter. Next, I did a similar experiment on transmit while watching reflected power and saw essentially the same effect. Theoretically, I think the added capacitance simply detunes the radiating element when a mast is really close, meaning an inch or less. Otherwise, the mast isn't seen as director, since the size is so far off. (Guessing is allowed, right?) Article: 223383 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Mon, 10 Apr 2006 03:54:56 -0700 Message-ID: <123kec3l8kg3s01@corp.supernews.com> References: <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> <1144634798.546962.8210@u72g2000cwu.googlegroups.com> <1144647060.456337.126840@e56g2000cwe.googlegroups.com> w8ji@akorn.net wrote: > Yuri Blanarovich wrote: > . . . >> Looks like Belrose should get another pHDuuhh for starting all this >> misconception and misinformation in ham literature. Pathetic is that some of >> the "gurus" that should know better, are on the same bandwagon to la-la >> land. > > I'm not sure what motivates you to attack everyone, but at least you > universally seem to hate almost everyone. Jack Belrose is a great guy > and has contributed a great deal with his work. If you finmd something > wrong with what he is saying, tell us what it is. Don't attack the > person, point out the error. Jack Belrose, VE2CV, is a highly respected engineer and scientist with an extensive and distinguished professional history. We're very fortunate that he's shared some small part of his extensive knowledge and experience with the amateur community. For a glimpse at his career, see http://www.friendsofcrc.ca/Articles/Belrose-EarlyYears/Belrose%20remembrances.html. No one is always right, but people like Jack have earned my respect and I'll always listen very carefully to what they have to say. Although it doesn't bear directly on his credibility, I've known him for many years and I heartily agree with Tom that he's a great guy. Roy Lewallen, W7EL Article: 223384 of rec.radio.amateur.antenna From: "Ken Bessler" References: <0g5og3-bsa.ln1@p400bob.personal.cox.net> <%3h_f.579$B42.454@dukeread05> Subject: Re: 16 el coaxial colinear (2.4ghz) question - How 'bout this? Message-ID: Date: Mon, 10 Apr 2006 07:17:25 -0500 "Bob Bob" wrote in message news:rdsog3-jfb.ln1@p400bob.personal.cox.net... > Hi Ken > I am surprised at the -97dBm sensitivity. Yea, it's a genuine Atheros card, not just an Atheros chipset. I bought it based on reports online touting it's high reciever performance and the fact that it is a mini PCI card, not a pcmcia card. > > One of you other posters suggested remoting the router box to remove the > cable loss problem. It is the place where most of your problems lie. > Even moving it part the distance will help. You might also look at a > better coax. We use to use LMR400 extensively. It was much cheaper than > RG213 and lower loss as well. That is what I was using - 40' of it. > > Oh and be careful with the WAP etc setup as regards "maximum distance". > We had a problem early on where we left it at the default for a 10km > path and the ACKs (or something) kept crashing and kept the speed down. > The distance number introduces some kind of ACK delay.. > > Good luck! > > Cheers Bob VK2YQA Thanks for all the help, Bob - 73! Ken KG0WX Article: 223385 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> <1144634798.546962.8210@u72g2000cwu.googlegroups.com> <1144647060.456337.126840@e56g2000cwe.googlegroups.com> Message-ID: Date: Mon, 10 Apr 2006 12:32:19 GMT w8ji@akorn.net wrote: > I already posted, years ago, measurements at: > > http://www.w8ji.com/mobile_antenna_current_measurements_at_w8ji.htm Those are RMS standing wave measurements. To see what is wrong with using RMS standing wave measurements please see: http://www.qsl.net/w5dxp/travstnd.GIF > I think what is happening here is you are getting angry and not paying > attention to what people are saying. I've already said it is possible > to have different currents at each end of a loading coil. And there phase information in those standing wave current magnitudes. There is no phase information is standing wave current phase. > What I disagree with you about is you seem to attribute that difference > to some magical property related to the distribution of current based > on electrical degrees the loading coil replaces or standing waves, and > that is very simply and clearly wrong. No, it is your misconceptions about standing wave current that are very simply and clearly wrong. > Current cannot "drop" or be "dropped". RF current drops with the attenuation factor, just like RF voltage does. Clinging to the lumped circuit model presuppositions is what causes you to make silly assertions like the above. Standing wave current periodically drops to zero in unterminated transmission lines. > The single thing that allows an inductor to have a current difference > and phase shift in current along the coil or at each terminal is the > capacitance of the coil to the outside world. Is capacitance to the outside world also what allows a wire to have zero current at one point and two amps of current 90 degrees away. Of course not! The degrees of delay through the coil is primarily responsible for the difference in current. That, and where it is places on the standing wave current curve. > You have to include displacement currents in any model, or you cannot > have a current taper along the length of a conductor. We are talking about displacement current to earth ground and there is zero displacement current to the outside world ground yet there's SWR current taper on coaxial transmission lines. Maybe it's time for you to learn how to add phasors? > Sure. His explanation of what is happening and the fact he picked a > very special conditions just to satisfy a twisted theory. Roy showed in > his models why Cecil's conclusions were wrong. Practical measurements > will show the same thing. Roy used standing wave current phase to try to measure the delay through a coil. That's an invalid measurement. None of my conditions are special. They just seem special to your lumped circuit model. The distributed network model works for all conditions. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223386 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> <1144634798.546962.8210@u72g2000cwu.googlegroups.com> <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <123kec3l8kg3s01@corp.supernews.com> Message-ID: Date: Mon, 10 Apr 2006 12:36:02 GMT Roy Lewallen wrote: > Jack Belrose, VE2CV, is a highly respected engineer and scientist with > an extensive and distinguished professional history. So are a lot of people who disagree with you. > No one is always right, ... You have known for a year now that standing wave current phase cannot be used to determine the delay through a coil yet you continue to post those invalid results. Guess you are proof of your own statement. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223387 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Mon, 10 Apr 2006 09:54:35 -0500 Message-ID: <3989-443A71AB-132@storefull-3256.bay.webtv.net> References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> Tom, W8JI wrote: "The ONLY thing that allows a conductor to have current taper along its length is displacement current." In a-c circuits, added to ordinary conduction current there is displacement current, at right angles to the direction of propagation, determined by the rate at which the field energy changes. Also at right angles to the direction of propagation, and determined by the rate at which energy changes, there is a changing magnetic field, in addition to the changing electric field. Together the electric and magnetic fields exchange energy and produce radiation. Displacement current which is the a-c current through a capacitor, that has no d-c conduction, is not the"ONLY" thing that allows a conductor to have a current taper along its length.. A conductor can lose energy through dissipation and radiation forever, not just relocate it temporarily through storage in a reactance. The dissipation line at the end of a rhombic antenna does not handle the entire output of the transmitter at its other end. Most of the energy is already radiated by the time it reaches the dissipation line. Best regards, Richard Harrison, KB5WZI Article: 223388 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> <1144634798.546962.8210@u72g2000cwu.googlegroups.com> <1144647060.456337.126840@e56g2000cwe.googlegroups.com> Message-ID: Date: Mon, 10 Apr 2006 15:12:46 GMT Cecil Moore wrote: > > We are talking about displacement current to earth ground and > there is zero displacement current to the outside world ground > yet there's SWR current taper on coaxial transmission lines. > Maybe it's time for you to learn how to add phasors? > Cecil, Sorry, you cannot pick and choose which displacement currents to consider. It might be helpful to go back to review the fundamentals of Maxwell's equations, including the continuity equation for current, before making these inane comments. 73, Gene W4SZ Article: 223389 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Message-ID: Date: Mon, 10 Apr 2006 15:24:21 GMT Richard Harrison wrote: > > Displacement current which is the a-c current through a capacitor, that > has no d-c conduction, is not the "ONLY" thing that allows a conductor to > have a current taper along its length.. > Richard, That is incorrect, and even Terman never said such a thing. Charge is not created or destroyed. It either keeps moving as current, or it is stored. Charge storage is the equivalent of displacement current. The terminology is slightly confusing at times, but it has not changed for over 100 years. Detailed discussions of this topic are found in virtually every intermediate and advanced textbook on electricity and magnetism. 73, Gene W4SZ Article: 223390 of rec.radio.amateur.antenna From: "Bill Ogden" References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> <123j34t8lqp37c5@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Mon, 10 Apr 2006 12:25:05 -0400 Speaking as a lurker, I find Roy's and Tom's postings very educational and I appreciate the time they take to do it. I am a little dense, but I think I have learned four key points (at least, key for me) from this material: 1. One can discuss transmission lines and antennas using pulse analysis or steady-state analysis. When these two are mixed together the results can be a mess. 2. When discussing "phase difference" we need to specify the two components that have the difference. (I.e., phase difference between the current into and out of an inductor is a different animal than the phase difference between current and voltage at a specific point.) 3. Superposition ("adding together") of power computations is not valid in reactive circuits. 4. Displacement current is as real as any other current when dealing with antennas and their components. (I cannot remember "displacement current" ever being mentioned back in the dark ages when I was in EE school. Perhaps the school should remain nameless.) Bill - W2WO Article: 223391 of rec.radio.amateur.antenna From: "Steve Nosko" Subject: Re: Please explain side lobe statement Date: Mon, 10 Apr 2006 10:39:32 -0500 Message-ID: References: <1144517308.519584.87760@e56g2000cwe.googlegroups.com> "Dave" wrote in message news:D9mdnWF-HcfoqKTZRVn-jw@crocker.com... > maybe their 'smaller' means smaller absolute values.. so that would give > numbers like -15db, -10db, etc... which would indeed be worse. Somebody finally got the problem. Side lobes smaller than -20 dB are better. Smaller than -20 dB is -25 dB, -30 dB. If it was stated as "-20 dB or less", that could/migh be interpreted as -15 dB, -10db. It is a language problem. Now... What was the OP really asking? and what was the author really trying to say? Probably what most assumed, but that isn't what he wrote. 73, Steve, K9DCI Article: 223392 of rec.radio.amateur.antenna From: "Steve Nosko" Subject: Re: Gamma. Before somebody tells me. Date: Mon, 10 Apr 2006 10:43:18 -0500 Message-ID: References: "Cecil Moore" wrote in message news:JqEZf.9270$4L1.2237@newssvr11.news.prodigy.com... > Reg Edwards wrote: > > But, believe it or not, under certain load conditions the reflection > > coefficient Gamma can exceed unity. Indeed, at a sufficiently low > > frequency, Gamma can approach 1+Sqrt(2) = 2.414 > > That agrees with Chipman who says it only occurs in lossy lines. > -- > 73, Cecil http://www.qsl.net/w5dxp Yes. A lossy line nas a non purely real (some X) Zo. Long distance power grid lines are such. 73, Steve, K9DCI Article: 223393 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Gamma. Before somebody tells me. References: Message-ID: Date: Mon, 10 Apr 2006 19:09:32 GMT Wes Stewart wrote: > On Mon, 10 Apr 2006 10:43:18 -0500, "Steve Nosko" > wrote: > > >>"Cecil Moore" wrote in message >>news:JqEZf.9270$4L1.2237@newssvr11.news.prodigy.com... >> >>>Reg Edwards wrote: >>> >>>>But, believe it or not, under certain load conditions the reflection >>>>coefficient Gamma can exceed unity. Indeed, at a sufficiently low >>>>frequency, Gamma can approach 1+Sqrt(2) = 2.414 >>> >>>That agrees with Chipman who says it only occurs in lossy lines. >>>-- >>>73, Cecil http://www.qsl.net/w5dxp >> >>Yes. A lossy line nas a non purely real (some X) Zo. > > > Or it doesn't. > > Chipman also says, "It has already been noted that if the losses are > due equally to R and G, Zo is real, no matter how high the losses > are." > > All you need is a line where R/L=G/C. This is the famous distortionless line. It was probably invented long before Chipman. I don't know what an amateur would want one for. 73, Tom Donaly, KA6RUH Article: 223394 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Mon, 10 Apr 2006 12:36:22 -0700 Message-ID: <123lctpbet35gd1@corp.supernews.com> References: <443422d4_4@newsfeed.slurp.net> <123dgvmajb4ihd5@corp.supernews.com> <3DzZf.337$Lm5.194@newssvr12.news.prodigy.com> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> <123j34t8lqp37c5@corp.supernews.com> I'm very glad to hear that our postings are being read and considered. Bill Ogden wrote: > Speaking as a lurker, I find Roy's and Tom's postings very educational and I > appreciate the time they take to do it. > > I am a little dense, but I think I have learned four key points (at least, > key for me) from this material: > > 1. One can discuss transmission lines and antennas using pulse analysis or > steady-state analysis. When these two are mixed together the results can be > a mess. True. You can actually translate from one to the other, but it requires an FFT or its inverse. Attempts to mix the two nearly always leads to invalid conclusions. > 2. When discussing "phase difference" we need to specify the two components > that have the difference. (I.e., phase difference between the current into > and out of an inductor is a different animal than the phase difference > between current and voltage at a specific point.) Yes, although we can use an arbitrary reference as long as it's the same for all components. For example, if one current has a phase angle of 50 degrees relative to some arbitrary reference and the other has a phase angle of 30 degrees relative to that same reference, we know that the phase of the first relative to the second is 20 degrees. > 3. Superposition ("adding together") of power computations is not valid in > reactive circuits. It's never valid. Let me give you an example. Consider two AC or DC voltage sources, each of 10 volts amplitude, with their negative terminals connected together. (If they're AC, have them be of the same frequency and in phase.) Connect a 10 ohm resistor between their positive terminals. Superposition says that we can analyze the circuit with each source individually and the other one turned off (short circuited in the case of a voltage source), and add the results. What we get should be the same answer as a full analysis with both the sources on at the same time. So let's do it. Turn off source #2. The current >from source #1 through the resistor is 1 amp. The voltage across the resistor is 10 volts. Now turn source #1 off and #2 on. The current through the resistor is 1 amp going the other way than before, or -1 amp. The voltage across the resistor is 10 volts, but in the opposite direction as before, or -10 volts. Adding the results gives a total of 0 amps through and 0 volts across the resistor. That's the right answer -- it's what we have when both sources are on. But now look at the power dissipated by the resistor. With only source #1 on, it's I^2 * R = 1^2 * 10 = 10 watts. With only source #2 on, it's (-1)^2 * 10 = 10 watts. The sum of the two is 20 watts, which is not the dissipation with both sources on. Superposition does not apply to power, period. If it ever seems to, it's only because of coincidence. Don't be confused by the "forward" and "reverse" power concept. This is not superposition and the concept must be used with great care to avoid reaching invalid conclusions. > 4. Displacement current is as real as any other current when dealing with > antennas and their components. (I cannot remember "displacement current" > ever being mentioned back in the dark ages when I was in EE school. Perhaps > the school should remain nameless.) It's a useful concept, but also has to be used with care because it isn't a real current consisting of movement of electrons. Current in one conductor creates a field which induces current in another conductor, making the current appear to have "flowed" from one conductor to the other. The classic example is of course current flow "through" a capacitor. "Displacement current" is a widely used term; it's in the index of the first four EM texts I grabbed from the bookshelf. Of an example of a parallel RC circuit in Kraus' _Electromagnetics_, he says, "The current through the resistor is a *conduction current*, while the current 'through' the capacitor may be called a *displacement current*. Although the current does not flow through the capacitor, the external effect is as though it did, since as much current flows out of one plate as flows into the opposite one." Displacement current appears in Ampere's law, one of the four Maxwell equations. In one formulation it has the quantity i + d(phi)e/dt on one side. The i is conduction current, and the derivative quantity is known as the displacement current. Roy Lewallen, W7EL Article: 223395 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: Current across the antenna loading coil - from scratch Date: Mon, 10 Apr 2006 16:04:56 -0400 Message-ID: References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Not that I could fan the flames any more anyhow, but just what was the original discussion about anyhow? As in Cecil says what, and those disagreeing with him say what? I'm curious how something that doesn't seem that complex can generate so many weeks of acrimony and vitriol! I don't know the answer - but then again, I'm not really sure what the question is. But I do know where to look it up.... - 73 de Mike KB3EIA - Article: 223396 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Gamma. Before somebody tells me. Message-ID: References: Date: Mon, 10 Apr 2006 20:48:38 GMT On Mon, 10 Apr 2006 10:25:07 -0700, Wes Stewart wrote: >On Mon, 10 Apr 2006 10:43:18 -0500, "Steve Nosko" > wrote: > >> >>"Cecil Moore" wrote in message >>news:JqEZf.9270$4L1.2237@newssvr11.news.prodigy.com... >>> Reg Edwards wrote: >>> > But, believe it or not, under certain load conditions the reflection >>> > coefficient Gamma can exceed unity. Indeed, at a sufficiently low >>> > frequency, Gamma can approach 1+Sqrt(2) = 2.414 >>> >>> That agrees with Chipman who says it only occurs in lossy lines. >>> -- >>> 73, Cecil http://www.qsl.net/w5dxp >> >>Yes. A lossy line nas a non purely real (some X) Zo. > >Or it doesn't. > >Chipman also says, "It has already been noted that if the losses are >due equally to R and G, Zo is real, no matter how high the losses >are." > "Distortionless lines" are lines with purely resistive Zo, and they include lossless lines and that class of lossy line. Owen -- Article: 223397 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Mon, 10 Apr 2006 17:19:29 -0400 Check my article that describes the controversy, shows some proof of reality and then efforts of the "gurus" to deny it and "reason" why it can't be so. http://www.k3bu.us/loadingcoils.htm The problem is that back in 1953 in QST article there was erroneous conclusion/statement made, which propagated through the books, until W9UCW measured the current across the loading coils and found that there is significant drop from one end to the other, and the rest is (ongoing) history Yuri, K3BU.us "Michael Coslo" wrote in message news:e1edpg$19le$1@f04n12.cac.psu.edu... > Not that I could fan the flames any more anyhow, but just what was the > original discussion about anyhow? > > As in Cecil says what, and those disagreeing with him say what? > > I'm curious how something that doesn't seem that complex can generate so > many weeks of acrimony and vitriol! I don't know the answer - but then > again, I'm not really sure what the question is. But I do know where to > look it up.... > > - 73 de Mike KB3EIA - Article: 223398 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Message-ID: Date: Mon, 10 Apr 2006 21:46:20 GMT Richard Harrison wrote: > A conductor can lose energy > through dissipation and radiation forever, not just relocate it > temporarily through storage in a reactance. > > The dissipation line at the end of a rhombic antenna does not handle the > entire output of the transmitter at its other end. Most of the energy is > already radiated by the time it reaches the dissipation line. For instance, consider 100 ft. of 50 ohm coax with losses of 3 dB driving a 50 ohm load from a source of 200 watts. At the source, we have 100 volts at 2 amps. At the load, we have 70.7 volts at 1.414 amps. The current dropped by exactly the same amount as the voltage. Hint: The V/I ratio must be maintained at 50 ohms for flat lines. Anyone who doesn't understand RF H-field (current) drop in a lossy transmission line has probably been so seduced by his lumped circuit model that he thinks the model dictates reality instead of vice versa. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223399 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <4432a7f4_5@newsfeed.slurp.net> <2eb5329scje915brj9gmb9sd17ejvcvm9t@4ax.com> <4432d00b_4@newsfeed.slurp.net> <4433b845_3@newsfeed.slurp.net> <443422d4_4@newsfeed.slurp.net> <2gl83250938id6bp54hodrkenm2mffnoje@4ax.com> <4434655c_5@newsfeed.slurp.net> <4434fb26_5@newsfeed.slurp.net> <1144385028.313255.108730@u72g2000cwu.googlegroups.com> <1144426107.667057.56500@e56g2000cwe.googlegroups.com> <1f%Zf.118$1C4.14@fe09.lga> <1144583024.698268.212720@z34g2000cwc.googlegroups.com> <1144634798.546962.8210@u72g2000cwu.googlegroups.com> <1144647060.456337.126840@e56g2000cwe.googlegroups.com> Message-ID: Date: Mon, 10 Apr 2006 21:50:25 GMT Gene Fuller wrote: > Sorry, you cannot pick and choose which displacement currents to consider. Why not? All I (and probably Yuri) have ever been considering are displacement currents to earth ground from the coil. That is the only current flowing sideways from the coil to ground. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223400 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Mon, 10 Apr 2006 14:57:25 -0700 Message-ID: <123ll68am31f5fd@corp.supernews.com> References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> <123j34t8lqp37c5@corp.supernews.com> <123lctpbet35gd1@corp.supernews.com> Tom Donaly wrote: > > Not everyone is happy with the term "displacement current." Albert > Shadowitz, in his book _The Electromagnetic Field_, has a chapter > entitled "The So-called Displacement Current." The term isn't in > the index to Feynman's _Lectures on Physics_. (At least I couldn't > find it.) All that is academic to the fact that AC current seems to > be able to make its way through a capacitor with no more opposition > than the capacitive reactance. Fortunately, no one on this > newsgroup has any objection to the way the term is commonly used. > 73, > Tom Donaly, KA6RUH That's interesting. It prompted me to look at my other electromagnetics texts. Of the eight I have (Johnk, Jordan & Balmain, Kraus, Ida, Majid, Holt, Ramo et al, and King), all include displacement current in the index and all discuss the concept. Only King objects to its use, although he notes that "The second term [in Ampere's law] was called the 'displacement current' by Maxwell, and this name continues to be used." He goes on to say that "Actually this terminology is unfortunate because the word displacement belongs to the old ether model and because the word current means specifically moving charge." He adds further reasons for his objection in the following paragraphs. With a copyright date of 1945, King's book (_Electromagnetic Engineering_, Vol. I) is the oldest of the texts I have. Perhaps the term has become more acceptable as time has passed. I do see why physicists such as Feynman wouldn't be accepting of the term. As I mentioned in my earlier posting, it does need to be used with care. We have to always keep in mind that it isn't a real current and therefore doesn't always behave like one. But it is a useful concept as long as we stay aware of its limitations. Roy Lewallen, W7EL Article: 223401 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: How get RF through a sealed window? Date: Mon, 10 Apr 2006 15:04:27 -0700 Message-ID: <123lljdreeb148a@corp.supernews.com> References: <1144705641.418367.163090@i40g2000cwc.googlegroups.com> n3ox.dan@gmail.com wrote: > . . . > I think your idea with capacitative coupling with inductors to tune out > the reactance would work fine too, but I haven't tried that. > . . . If you do try that, I recommend keeping the Q as low as possible. Otherwise, voltages will get very high, and you might well end up with greater loss as well as other problems. Minimizing the Q means keeping reactance values low which in turn means making C as large as possible. This leaves you with less reactance to compensate for. In other words, don't make the C small and try to compensate for the large amount of resulting reactance. Roy Lewallen, W7EL Article: 223402 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Message-ID: <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> Date: Mon, 10 Apr 2006 22:12:13 GMT Michael Coslo wrote: > Not that I could fan the flames any more anyhow, but just what was the > original discussion about anyhow? As I realized what the actual misconception really is, the discussion shifted from coils to standing waves. Seems to me, W8JI and W7EL do not understand the difference implied by these two different equations (assuming |Ifor|=|Iref|). Ifor = I1*cos(kx+wt) and Iref = I1*cos(kx-wt) Istnd = I1*cos(kx+wt) + I1*cos(kx-wt) = I2*cos(kx)*cos(wt) Gene Fuller has kindly explained the difference but W8JI and W7EL seemed to have ignored his explanation. Gene says there is no phase information in standing wave current phase and I agree. > As in Cecil says what, and those disagreeing with him say what? Looking at: http://www.qsl.net/w5dxp/travstnd.GIF I say the RMS standing wave current's unchanging phase on the right hand graph, cannot be used to measure phase. W7EL continues to report those phase measurements as valid indicators of delay through coils when installed in standing wave environments. I say all the phase information in the standing wave current is in its magnitude which is a cosine function as explained in Kraus and Terman. W8JI and W7EL both dismiss the phase information in the standing wave magnitude and insteadtrust the standing wave phase to yield valid delay measurements. > I'm curious how something that doesn't seem that complex can > generate so many weeks of acrimony and vitriol! I don't know the answer > - but then again, I'm not really sure what the question is. But I do > know where to look it up.... Now you know what the argument is about. Seems to me, W8JI, W7EL, and others possess misconceptions caused by assuming the unproven presuppositions of their lumped circuit model. They "prove" their misconceptions by making measurements known to be invalid. I can't tell if they are aware of what they are doing or not. If you know where to look for the answer, please tell us. I have looked and only found a clear explaination in "Optics" by Hecht. A side argument is whether standing wave current can drop to zero at a node in an unterminated transmission line. W8JI continues to assert that current cannot drop without some imagined third path. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223403 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Gamma. Before somebody tells me. References: Message-ID: Date: Mon, 10 Apr 2006 22:14:45 GMT Owen Duffy wrote: > "Distortionless lines" are lines with purely resistive Zo, and they > include lossless lines and that class of lossy line. Re rho > 1, Chipman is not talking about "distortionless lines". He specifically states that it occurs when the reactive portion of Z0 is of opposite sign to the load reactance. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223404 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> <123j34t8lqp37c5@corp.supernews.com> <123lctpbet35gd1@corp.supernews.com> Message-ID: Date: Mon, 10 Apr 2006 22:19:27 GMT Tom Donaly wrote: > Not everyone is happy with the term "displacement current." Albert > Shadowitz, in his book _The Electromagnetic Field_, has a chapter > entitled "The So-called Displacement Current." The term isn't in > the index to Feynman's _Lectures on Physics_. (At least I couldn't > find it.) All that is academic to the fact that AC current seems to > be able to make its way through a capacitor with no more opposition > than the capacitive reactance. Fortunately, no one on this > newsgroup has any objection to the way the term is commonly used. Here's an associated quote from "Electromagnetic Engineering" by R.W.P King: "an adequate representation of the reactance of a coil with a nonuniformly distributed current is NOT POSSIBLE in terms of a coil with a uniform current [a lumped- element inductance] connected in parallel with a lumped capacitance." -- 73, Cecil http://www.qsl.net/w5dxp Article: 223405 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> Message-ID: Date: Mon, 10 Apr 2006 22:21:07 GMT Cecil Moore wrote: > > Gene Fuller has kindly explained the difference but W8JI and W7EL > seemed to have ignored his explanation. Cecil, Give it up on this line of baloney. There is not the slightest bit of disagreement on the nature of traveling waves and standing waves. The only person who was ever appeared to be confused was you. I am happy that you seem to now have at least partial understanding. 73, Gene W4SZ Article: 223406 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Message-ID: Date: Mon, 10 Apr 2006 22:32:53 GMT Mike, The question changes continuously. As soon as one myth is exploded Cecil slides right into another. The original topic dealt with currents in a loading coil for a mobile antenna. However, the technical part of that discussion ended a long time ago. Only the sniping remains. 73, Gene W4SZ Michael Coslo wrote: > Not that I could fan the flames any more anyhow, but just what was the > original discussion about anyhow? > > As in Cecil says what, and those disagreeing with him say what? > > I'm curious how something that doesn't seem that complex can > generate so many weeks of acrimony and vitriol! I don't know the answer > - but then again, I'm not really sure what the question is. But I do > know where to look it up.... > > - 73 de Mike KB3EIA - Article: 223407 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Mon, 10 Apr 2006 17:27:49 -0500 Message-ID: <6795-443ADBE5-38@storefull-3251.bay.webtv.net> References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> Gene Fuller wrote: "This is incorrect, and even Terman never said such a thing." I had written: "Displacement current which is the a-c current through a capacitor, that has no a-c conduction, is not the "ONLY" thing that allows a conductor to have a current taper." It was Tom, W8JI who shouted: "The ONLY thing etc." I just said displacement current is NOT the only thing. Energy level often declines between ends of a wire or coil due to losses from radiation or dissipation in the wire or coil. Tom is mistaken. I don`t find the subject of "displacement current" listed in my Terman`s index. I think its definition is accepted. but I gave mine in case someone did not understand what it is. J.C. Maxwell unlocked the secret of radiation when he speculated displacement current would produce magnetic lines of force the same as conduction current does, thus a traveling E-field produces an H-field and vice versa. It`s been proved correct. Terman writes on page 1 of his 1955 edition: "Electrical energy that has escaped into free space exists in the form of electromagnetic waves. These waves, which are commonly called radio waves, travel with the velocity of light and consist of magnetic and electric fields that are at right angles to each other and at right angles to the direction of travel." Terman writes on page 866 of his 1955 edition in his chapter on "Antennas": "A wire antenna is a circuit with distributed constants; hence the current distribution on a wire antenna that results from application of a localized voltage follows the principles discussed in Chapt. 4, (titled"Transmission Lines") and depends upon the antenna length; mesured in wavelengths; the terminations at the ends of the antenna wire; and the losses in the system." Nothing I wrote conflicts with Terman. That`s not the kind of fool I am. Best regards, Richard Harrison, KB5WZI Article: 223408 of rec.radio.amateur.antenna From: ml Subject: Re: vert distortion? References: <4s4i329os8b7cjt5ndgtlrk17tl56ouo3s@4ax.com> Message-ID: Date: Mon, 10 Apr 2006 22:40:22 GMT In article <4s4i329os8b7cjt5ndgtlrk17tl56ouo3s@4ax.com>, Wes Stewart wrote: > On Sun, 09 Apr 2006 13:18:18 GMT, ml wrote: > > >hi > > > > > >i've noticed a few installations of say a 2m beam vertically mounted to > >a regular metal tv style mast > > > >from looking at it, you have the mast(metal) going between 2 elements > >and longer than the elements > > > >so i was wondering as this is a common mounting style and method > > > >how bad is the beam pattern for rx and tx ? effected by the metal mast? > > > > > > > >it also got me thinking i've noteced some beams as in the above use a > >fiberglass boom while others use metal > > > >how does this effect patterns and efficiency > > > >both from a practical point of view and technically speaking > > The metal mast affects the performance to some degree, but I don't > know of a rule of thumb for predicting it. So the answer is, it > depends. > > A fiberglass or other non-metallic mast will help, it you also use a > non-metallic coax line. > > > > > > > > >??? > > > > > >thanks thanks for the interesting reply's , i was originally wondering how it would negatively effect it, which is my concern and knowing in what ways, but the j pole thing got me sorta thinkn' once i know the downside specifics' perhaps i might be able to turn it into a good thing?? cool Article: 223409 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> Message-ID: Date: Mon, 10 Apr 2006 22:44:04 GMT Gene Fuller wrote: > Cecil Moore wrote: >> Gene Fuller has kindly explained the difference but W8JI and W7EL >> seemed to have ignored his explanation. > > Give it up on this line of baloney. There is not the slightest bit of > disagreement on the nature of traveling waves and standing waves. On the contrary, you must not have read W7EL's recent posting where he again presented his coil delay "measurements" using the standing current phase as a measurement reference. Remember, the current you said contains no phase information? Maybe you should share your knowledge with W7EL? > The only person who was ever appeared to be confused was you. I am > happy Regarding the cos(kz)*cos(wt) term in a standing wave: When you made your posting, you reinforced my argument better than any other reference. I am very happy with your posting and cannot thank you enough. I will continue to use it as one of my best references for the invalidity of W7EL's coil delay measurements. Gene Fuller, W4SZ wrote: > In a standing wave antenna problem, such as the one you describe, > there is no remaining phase information. Any specific phase > characteristics of the traveling waves died out when the startup > transients died out. > > Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be > seen again. > > The only "phase" remaining is the cos (kz) term, which is really > an amplitude description, not a phase. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223410 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> Message-ID: <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> Date: Mon, 10 Apr 2006 22:54:56 GMT w8ji@akorn.net wrote: > I know you aren't going to like to hear this, but your article > incorrectly claims the current difference (you call it current drop) is > related to the electrical degrees the coil replaces. > That is not accurate. The current drop in a wire with standing waves is indeed related to the number of degrees occupied by the wire. Why shouldn't the same thing be true for a coil? > Consider a short vertical antenna. Consider a 1/4WL vertical antenna. The current drop is a function of the cosine of the number of degrees one moves away from the source. The same thing is true for a helical antenna. The same thing is true for a half helical - half wire antenna. > I guess it all comes down to if Barry and Yuri are right, or if nearly > every professor, scientist, and engineer from Maxwell to today are > correct. I can measure ANY antenna and prove things behave as I > described. Can you do the same? 1. You assume the unproven presuppositions of your lumped circuit model with a religious-like fervor. 2. You make invalid measurements using standing wave current whose phase contains no phase information. All the phase information is known to be in the magnitude measurement, but you dismiss any of the proven arc-cosine calculations as bogus. With misconceptions and invalid measurements, it is no wonder that you can prove anything in the world even when it violates the laws of physics. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223411 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Message-ID: <0tB_f.67500$Jd.34705@newssvr25.news.prodigy.net> Date: Mon, 10 Apr 2006 23:01:16 GMT Gene Fuller wrote: > The question changes continuously. As soon as one myth is exploded Cecil > slides right into another. Would you rather discuss something for which no disagreement exists, or discuss the real point of disagreement? It is apparent to me that the problem is not with coils. The same point of disagreement exists whether a coil is present or not. That point of disagreement involves standing waves, not coils. Take away the coil and the misconception still exists when discussing only a straight wire. W8JI is still maintaining that the current cannot drop to zero at a standing wave current node when the forward current and reflected current are of the same magnitude. That is obviously the point of misconception and it has been clear ever since he refused to discuss zero amps at the bottom of the coil and 2 amps at the top of the coil. Replace the coil with a straight wire and W8JI still has that same misconception. So you see the coil is not the source of the disagreement. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223412 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> Message-ID: Date: Mon, 10 Apr 2006 23:37:28 GMT Hi Richard, My point is in complete agreement with Tom, W8JI. The only thing that allows "current taper" is displacement current. Conservation of charge is one of the most fundamental laws in nature. The historical basis for referring to storage of charge in a capacitor as "displacement current" is considered incorrect today. However, the underlying physical science remains intact. "Current taper" means that charge stops moving as current and becomes stored in a capacitor. (Everything has capacitance; there is no requirement for a little lump with two leads on it.) It is this charge storage phenomenon that is known as displacement current. Energy levels and losses have nothing to do with this question. 73, Gene W4SZ Richard Harrison wrote: > Gene Fuller wrote: > "This is incorrect, and even Terman never said such a thing." > > I had written: > "Displacement current which is the a-c current through a capacitor, that > has no a-c conduction, is not the "ONLY" thing that allows a conductor > to have a current taper." It was Tom, W8JI who shouted: "The ONLY thing > etc." I just said displacement current is NOT the only thing. Energy > level often declines between ends of a wire or coil due to losses from > radiation or dissipation in the wire or coil. Tom is mistaken. Article: 223413 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> Message-ID: <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> Date: Tue, 11 Apr 2006 00:03:13 GMT Cecil, Your own calculations would appear to support Tom's assertion. I believe after a long series of EZNEC models and RRAA messages you came to the conclusion that the 75 meter bugcatcher coil at 4 MHz had a traveling wave phase shift of around 10 degrees. I won't get into the discussion about whether this has any bearing on a standing wave antenna; let's just assume it does. This same coil resonated an antenna with a whip length of 10 feet or so. A quarter wavelength at 4 MHz is around 60 feet. The phase shift that could be attributed to the whip is therefore around 15 degrees. The phase shift of the missing 50 feet of wire for a plain quarter wave antenna would be around 75 degrees. Is 10 degrees the same amount as 75 degrees? Is this problem stated incorrectly? Why is Tom wrong? 73, W4SZ Cecil Moore wrote: > w8ji@akorn.net wrote: > >> I know you aren't going to like to hear this, but your article >> incorrectly claims the current difference (you call it current drop) is >> related to the electrical degrees the coil replaces. >> That is not accurate. > > > The current drop in a wire with standing waves is indeed related > to the number of degrees occupied by the wire. Why shouldn't the > same thing be true for a coil? > Article: 223414 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> Message-ID: <%xC_f.58017$F_3.48039@newssvr29.news.prodigy.net> Date: Tue, 11 Apr 2006 00:14:51 GMT Gene Fuller wrote: > My point is in complete agreement with Tom, W8JI. The only thing that > allows "current taper" is displacement current. True, but it doesn't happen as W8JI describes. The distributed capacitance in a coil causes a transmission line effect. The displacement currents cause delays (phase shifts) in traveling wave currents. The traveling wave currents can be considered to have constant magnitude, i.e. *negligible current taper* in the traveling wave in spite of the known displacement currents. The displacement current effect on traveling waves is in the phase, not the magnitude. Such is illustrated as an EZNEC result in the left hand graphic at: http://www.qsl.net/w5dxp/travstnd.GIF Please note that in spite of the distributed capacitance, the magnitude is fixed and flat, i.e. no taper. The displacement currents cause phase shift delays in traveling waves but has virtually no effect on the magnitude of the traveling wave. The distributed capacitance is the same in the transmission line whether a single traveling wave is present or standing waves present. So displacement currents don't necessarily result in current taper. How do you explain that one? Now take a look at the right hand graph involving standing wave current. The *phase is fixed and unchanging*. The magnitude of the standing wave current is *tapered as a cosine function of distance from the source*. Displacement current indeed does cause this effect but it is a transmission line effect of superposition of forward and reflected waves, not the effect of some imagined sideways third path for current to earth ground. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223415 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> <%xC_f.58017$F_3.48039@newssvr29.news.prodigy.net> Message-ID: <7HC_f.5748$YT1.539@bgtnsc04-news.ops.worldnet.att.net> Date: Tue, 11 Apr 2006 00:24:35 GMT Cecil, All I can say is why don't you write this magic tale into a technical article and submit it to your favorite IEEE journal or AIP journal. 73, Gene W4SZ Cecil Moore wrote: > Gene Fuller wrote: > >> My point is in complete agreement with Tom, W8JI. The only thing that >> allows "current taper" is displacement current. > > > True, but it doesn't happen as W8JI describes. > > The distributed capacitance in a coil causes a transmission > line effect. The displacement currents cause delays (phase > shifts) in traveling wave currents. The traveling wave > currents can be considered to have constant magnitude, i.e. > *negligible current taper* in the traveling wave in spite > of the known displacement currents. > > The displacement current effect on traveling waves is in > the phase, not the magnitude. Such is illustrated as an > EZNEC result in the left hand graphic at: > > http://www.qsl.net/w5dxp/travstnd.GIF > > Please note that in spite of the distributed capacitance, > the magnitude is fixed and flat, i.e. no taper. The displacement > currents cause phase shift delays in traveling waves but has > virtually no effect on the magnitude of the traveling wave. > > The distributed capacitance is the same in the transmission > line whether a single traveling wave is present or standing > waves present. So displacement currents don't necessarily > result in current taper. How do you explain that one? > > Now take a look at the right hand graph involving standing > wave current. The *phase is fixed and unchanging*. The magnitude > of the standing wave current is *tapered as a cosine function > of distance from the source*. Displacement current indeed does > cause this effect but it is a transmission line effect of > superposition of forward and reflected waves, not the effect > of some imagined sideways third path for current to earth ground. Article: 223416 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> Message-ID: Date: Tue, 11 Apr 2006 00:44:02 GMT Gene Fuller wrote: > I believe after a long series of EZNEC models and RRAA messages you came > to the conclusion that the 75 meter bugcatcher coil at 4 MHz had a > traveling wave phase shift of around 10 degrees. Note that is not a measurement - that is what EZNEC reports but let's assume, for the sake of discussion, that it is correct. W8JI measured a 3nS, 4 degree phase shift in a coil twice as long with 43% more inductance. A bigger coil would obviously have a bigger phase shift because of less current field linkage between the end coils. So even if the phase shift through the coil is 10 degrees as reported by EZNEC, W8JI's phase shift measurements were probably off by *MORE THAN 200%* and that's why Tom is wrong. > This same coil resonated an antenna with a whip length of 10 feet or so. > A quarter wavelength at 4 MHz is around 60 feet. The phase shift that > could be attributed to the whip is therefore around 15 degrees. The > phase shift of the missing 50 feet of wire for a plain quarter wave > antenna would be around 75 degrees. You are confused. Some time ago, I explained why a mobile antenna may not be 90 degrees long at all. Did you understand that posting? All we can say is that (Vfor+Vref)/(Ifor+Iref) is purely resistive. We don't know how many degrees the reflected wave has traveled in its round trip because there are too many variables. So please stop the diversions. I have always said that the delay through a coil *IS WHAT IT IS* but it is NOT zero and it is not the 3 nS measured by W8JI for that 100 uH coil. It is also not the near-zero phase shift measured by W7EL using standing wave current phase as the reference. You, yourself, implied that is an invalid measurement when you told us there is no phase information in standing wave phase. Seems to me you are making my argument for me and that your real argument is with the other side. Have you told W7EL that standing wave current phase cannot be used to measure the delay through a coil? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223417 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> <1144715023.730193.164820@i39g2000cwa.googlegroups.com> Message-ID: <%cD_f.58030$F_3.1988@newssvr29.news.prodigy.net> Date: Tue, 11 Apr 2006 01:00:43 GMT w8ji@akorn.net wrote: > Radiation does not cause current taper. Dissipation does not either. Radiation and dissipation are considered to be losses in a transmission line covered by the attenuation factor. All that is needed to prove your above assertions to be false is to quote a transmission line equation. It can even be the more simple flat form where the SWR is 1:1. Here it is in ASCII: I = Im*e^(ax)*e^j(wt-bx) Note this is the equation for *CURRENT* where 'a' is the attenuation factor. The attenuation factor includes radiation and dissipation. Your statements indicate a high level of ignorance. Assuming a flat transmission line with an SWR of 1:1, if the loss in the transmission line is 3 dB, we can put 200 watts into 50 ohm coax at the source end and get 100 watts out at the 50 ohm load end. The current out of the source is SQRT(200w/50) = 2 amps. The current through the 50 ohm load is SQRT(200w/50) = 1.414 amps. The current has dropped from the source to the load by exactly the same percentage that the voltage has dropped. What you seem to be missing is that the H-field is attenuated by the same amount as the E-field while the ratio of E-field to H-field remains constant and equal to Z0. Current is proportional to the H-field and voltage is proportional to the E-field. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223418 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> <%xC_f.58017$F_3.48039@newssvr29.news.prodigy.net> <7HC_f.5748$YT1.539@bgtnsc04-news.ops.worldnet.att.net> Message-ID: Date: Tue, 11 Apr 2006 01:04:43 GMT Gene Fuller wrote: > All I can say is why don't you write this magic tale into a technical > article and submit it to your favorite IEEE journal or AIP journal. I'm sure there are hundreds of such papers already, Gene. Much of this stuff is in the Corum paper. But you rejected that Corum IEEE paper that I presented as evidence so why would me writing one make any difference to your fixed preconceptions? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223419 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <%cD_f.58030$F_3.1988@newssvr29.news.prodigy.net> Message-ID: Date: Tue, 11 Apr 2006 01:08:36 GMT Cecil Moore wrote: > w8ji@akorn.net wrote: > >> Radiation does not cause current taper. Dissipation does not either. > > > Radiation and dissipation are considered to be losses in a > transmission line covered by the attenuation factor. All that > is needed to prove your above assertions to be false is to > quote a transmission line equation. It can even be the more > simple flat form where the SWR is 1:1. Here it is in ASCII: > > I = Im*e^(ax)*e^j(wt-bx) > > Note this is the equation for *CURRENT* where 'a' is the attenuation > factor. The attenuation factor includes radiation and dissipation. > > Your statements indicate a high level of ignorance. Assuming a flat > transmission line with an SWR of 1:1, if the loss in the transmission > line is 3 dB, we can put 200 watts into 50 ohm coax at the source end > and get 100 watts out at the 50 ohm load end. The current out of the > source is SQRT(200w/50) = 2 amps. The current through the 50 ohm load > is SQRT(200w/50) = 1.414 amps. The current has dropped from the source ^^^ Obviously, should be 100w. Sorry for the typo. > to the load by exactly the same percentage that the voltage has dropped. > > What you seem to be missing is that the H-field is attenuated by the > same amount as the E-field while the ratio of E-field to H-field > remains constant and equal to Z0. Current is proportional to the > H-field and voltage is proportional to the E-field. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223420 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> Message-ID: Date: Tue, 11 Apr 2006 02:20:34 GMT Cecil, As usual, you evaded the question, but this time you did not even do a very slick job of evasion. The question is what happens to the 75 degrees that was formerly represented by the now-replaced wire. The coil may offer about 10 degrees. I believe that Tom is stating that 75 is not equal to 10. Sounds like a reasonable statement to me. I don't know why you are so worried about the precise details of phase measurements. Even your standard of precision, +/- 59%, won't make 10 equal to 75. 73, Gene W4SZ Cecil Moore wrote: > Gene Fuller wrote: > > I believe after a long series of EZNEC models and RRAA messages you came > > to the conclusion that the 75 meter bugcatcher coil at 4 MHz had a > > traveling wave phase shift of around 10 degrees. > > Note that is not a measurement - that is what EZNEC reports but > let's assume, for the sake of discussion, that it is correct. W8JI > measured a 3nS, 4 degree phase shift in a coil twice as long with > 43% more inductance. A bigger coil would obviously have a bigger > phase shift because of less current field linkage between the end > coils. So even if the phase shift through the coil is 10 degrees > as reported by EZNEC, W8JI's phase shift measurements were probably > off by *MORE THAN 200%* and that's why Tom is wrong. > > > This same coil resonated an antenna with a whip length of 10 feet or so. > > A quarter wavelength at 4 MHz is around 60 feet. The phase shift that > > could be attributed to the whip is therefore around 15 degrees. The > > phase shift of the missing 50 feet of wire for a plain quarter wave > > antenna would be around 75 degrees. > > You are confused. Some time ago, I explained why a mobile antenna > may not be 90 degrees long at all. Did you understand that posting? > All we can say is that (Vfor+Vref)/(Ifor+Iref) is purely resistive. > We don't know how many degrees the reflected wave has traveled in > its round trip because there are too many variables. > > So please stop the diversions. I have always said that the delay > through a coil *IS WHAT IT IS* but it is NOT zero and it is not the > 3 nS measured by W8JI for that 100 uH coil. It is also not the near-zero > phase shift measured by W7EL using standing wave current phase as the > reference. You, yourself, implied that is an invalid measurement when > you told us there is no phase information in standing wave phase. > > Seems to me you are making my argument for me and that your real > argument is with the other side. Have you told W7EL that standing > wave current phase cannot be used to measure the delay through a > coil? Article: 223421 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <%cD_f.58030$F_3.1988@newssvr29.news.prodigy.net> Message-ID: Date: Tue, 11 Apr 2006 02:27:47 GMT Cecil, Wow! I think you may have set a new world record for the most irrelevant concepts per word dragged into an RRAA posting. We got transmission lines, attenuation factors, H-fields, E-fields, and even SWR. Not to mention watts, dB, and Zo. It is truly unfortunate that none of this is connected to the subject at hand, displacement current, but it makes for a colorful message. 73, Gene W4SZ Cecil Moore wrote: > w8ji@akorn.net wrote: > >> Radiation does not cause current taper. Dissipation does not either. > > > Radiation and dissipation are considered to be losses in a > transmission line covered by the attenuation factor. All that > is needed to prove your above assertions to be false is to > quote a transmission line equation. It can even be the more > simple flat form where the SWR is 1:1. Here it is in ASCII: > > I = Im*e^(ax)*e^j(wt-bx) > > Note this is the equation for *CURRENT* where 'a' is the attenuation > factor. The attenuation factor includes radiation and dissipation. > > Your statements indicate a high level of ignorance. Assuming a flat > transmission line with an SWR of 1:1, if the loss in the transmission > line is 3 dB, we can put 200 watts into 50 ohm coax at the source end > and get 100 watts out at the 50 ohm load end. The current out of the > source is SQRT(200w/50) = 2 amps. The current through the 50 ohm load > is SQRT(200w/50) = 1.414 amps. The current has dropped from the source > to the load by exactly the same percentage that the voltage has dropped. > > What you seem to be missing is that the H-field is attenuated by the > same amount as the E-field while the ratio of E-field to H-field > remains constant and equal to Z0. Current is proportional to the > H-field and voltage is proportional to the E-field. Article: 223422 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> Message-ID: Date: Tue, 11 Apr 2006 02:38:22 GMT Cecil Moore wrote: > Michael Coslo wrote: > >> Not that I could fan the flames any more anyhow, but just what was the >> original discussion about anyhow? > > > As I realized what the actual misconception really is, the discussion > shifted from coils to standing waves. Seems to me, W8JI and W7EL do > not understand the difference implied by these two different equations > (assuming |Ifor|=|Iref|). > > Ifor = I1*cos(kx+wt) and Iref = I1*cos(kx-wt) > > Istnd = I1*cos(kx+wt) + I1*cos(kx-wt) = I2*cos(kx)*cos(wt) > > Gene Fuller has kindly explained the difference but W8JI and W7EL > seemed to have ignored his explanation. Gene says there is no > phase information in standing wave current phase and I agree. > >> > I've said it before and I'll say it again, there is no phase variable in I1*cos(kx+wt) and there is no phase variable in I1*cos(kx-wt) so there can't possibly be any phase information in 2*I1*cos(kx)*cos(wt). If you're going to measure a phase difference between two places on a transmission line and you want to write an equation describing what you're doing, you have to have the phase variable somewhere in your equation so you can solve for it. Also, it would help, Cecil, if you would be a little more careful when you copy these equations from your favorite Bible. They keep changing form as time passes. 73, Tom Donaly, KA6RUH Article: 223423 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144527265.990824.208890@i40g2000cwc.googlegroups.com> <123hi0fb91l66ab@corp.supernews.com> <123j34t8lqp37c5@corp.supernews.com> <123lctpbet35gd1@corp.supernews.com> Message-ID: Date: Tue, 11 Apr 2006 02:48:14 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> Not everyone is happy with the term "displacement current." Albert >> Shadowitz, in his book _The Electromagnetic Field_, has a chapter >> entitled "The So-called Displacement Current." The term isn't in >> the index to Feynman's _Lectures on Physics_. (At least I couldn't >> find it.) All that is academic to the fact that AC current seems to >> be able to make its way through a capacitor with no more opposition >> than the capacitive reactance. Fortunately, no one on this >> newsgroup has any objection to the way the term is commonly used. > > > Here's an associated quote from "Electromagnetic Engineering" > by R.W.P King: "an adequate representation of the reactance > of a coil with a nonuniformly distributed current is NOT > POSSIBLE in terms of a coil with a uniform current [a lumped- > element inductance] connected in parallel with a lumped > capacitance." I don't know what that has to do with displacement current, Cecil, but if you're worried about it you can just use your coil at a frequency where you get a more satisfactory current distribution. I made a coil like you talk about (mine was 5.25 inches long, 27 turns, 6 inches in diameter) and it behaved pretty much like a coil in parallel with a capacitor up to a few megahertz, at least. Beyond that, it was a different story. 73, Tom Donaly, KA6RUH Article: 223424 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Mon, 10 Apr 2006 23:05:48 -0400 wrote > There is not any magic to any of this, and we don't need to have > standing waves. rest of mumbo-jumbo nonsense deleted Tom, So, you don't need to have standing waves on the resonant radiator? If you see antenna and loading coil in it as coil in a closed circuit and not as resonator with standing wave, then you are off the rocker. You don't know what the impedance is. You don't want to repeat tests that W9UCW did. You don't want to explain W5DXP models and answer his questions. You don't want answer my question, but resort every time into "lessons" about your misconceptions. I tried to go step by step, starting with resonant quarter wave and current distribution along its length, but you get off on your lecture tangent to muddy the waters and how you can make a coil that will have difference in current, while you stated at the begining that the current is ALWAYS the same. Now the stray capacitance can suck the current out of the antenna? Read Kraus what he says about antenna (resonator), standing wave and energy in it. You can measure it, just as W9UCW did. Keep it up! 73 Yuri I just pointed out that Belrose apparently started this misconception in his 1953 QST article, got perpetuated in ham literature until it hit us in the face and we pointed out that it is wrong and now has impact on modeling and antenna design. Garbage in - garbage out. We are trying to correct it and show what the reality is. Article: 223425 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Grounding Bar Length For Receiving Only Antenna References: Message-ID: Date: Tue, 11 Apr 2006 03:19:49 GMT TimPerry wrote: > "Robert11" wrote in message > news:QLedndZlQrktXqfZnZ2dnUVZ_tCdnZ2d@comcast.com... > >>Hello: >> >>Just started to string up the new listening only antenna I purchased from >>PAR. >> >>As there is a Balun between the start of the wire antenna, and the coax >>feeding the receiver, a ground bar is apparently required. >> >>Am using the typical eight foot long,5/8" diameter Cu plated steel that I >>guess is fairly typical for house AC power grounding. >> >>Querstion: At my age, it's a bit of a problem pounding in the six or > > seven > >>feet that is commonly mentioned as the "required" length. Certainly, the >>more the better, I guess, but what wqould be a reasonable length into the >>ground ? >>How about 4 to 5 feet ? Again, it's for receiving only. >> >>Thanks, >>Bob >> > > > you can make a ground rod pounder by coupling several short section of pipe > together. the ground rod is inserted into the pipe which keeps the rod from > bending. as the rod is driven into the ground sections are removed one at a > time until the rod is at sufficient depth. > > it's getting it out thats the trickey part :) > > Place a clamp on the exposed end of the rod and connect it to an automobile bumper jack, the old fashioned kind that actually fit the bumper. Jack the jack and it will pull the rod out of the ground. As it appears you can reposition the clamp and lower the jack to another lift point. Wa la one out of the ground ground rod. Dave WD9BDZ Article: 223426 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <3989-443A71AB-132@storefull-3256.bay.webtv.net> <6795-443ADBE5-38@storefull-3251.bay.webtv.net> <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <%cD_f.58030$F_3.1988@newssvr29.news.prodigy.net> Message-ID: Date: Tue, 11 Apr 2006 03:36:21 GMT Gene Fuller wrote: > It is truly unfortunate that none of this is connected to the subject at > hand, displacement current, but it makes for a colorful message. Please don't tell us that you don't understand how the attenuation factor in a transmission line current equation causes the current to drop along the line equaling the percentage drop in the voltage. One can write a similar equation for a standing wave dipole. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223427 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> Message-ID: Date: Tue, 11 Apr 2006 04:03:20 GMT Tom Donaly wrote: > I've said it before and I'll say it again, there is no phase variable > in I1*cos(kx+wt) and there is no phase variable in I1*cos(kx-wt) so > there can't possibly be any phase information in 2*I1*cos(kx)*cos(wt). Sorry, you are wrong about that. EZNEC reports that phase information. Assuming the EZNEC default convention, the source is 1.0 amp at zero degrees at t=0. So the RMS value of the traveling wave current is 1.0 amp at -'kx' degrees. -'kx' *IS* the phase angle of the current up and down the wire referenced to the source. It is negative because the source naturally leads the traveling wave. Note 'kx' is how far the point of interest is away from the source in degrees. Doesn't anyone understand phasors anymore? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223428 of rec.radio.amateur.antenna From: Dave Heil Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <0YCZf.68027$dW3.47946@newssvr21.news.prodigy.com> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> Message-ID: <1VF_f.2221$BS2.651@newsread1.news.pas.earthlink.net> Date: Tue, 11 Apr 2006 04:04:13 GMT Cecil Moore wrote: > John Popelish wrote: >> If you have no interest in anything but butting heads with the people >> who have disagreed with you, then, please stop responding to my posts. > > If you are into playing games, you are responding to the > wrong person. Try W8JI or W7EL instead. Heck, Cecil, you had years of participation in r.r.a.p. during which you were a pregnant man, a 300 foot tall alien or you were challenging others to dunk a basketball. I'd say that game playing is one of your favorite things. Dave Heil K8MN Article: 223429 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <443422d4_4@newsfeed.slurp.net> <6XDZf.9261$4L1.5262@newssvr11.news.prodigy.com> <1144504210.747890.110740@i39g2000cwa.googlegroups.com> <1144520657.700666.313670@g10g2000cwb.googlegroups.com> <7wUZf.534$Lm5.351@newssvr12.news.prodigy.com> <1144540691.783872.197170@v46g2000cwv.googlegroups.com> <1VF_f.2221$BS2.651@newsread1.news.pas.earthlink.net> Message-ID: Date: Tue, 11 Apr 2006 04:06:44 GMT Dave Heil wrote: > Heck, Cecil, you had years of participation in r.r.a.p. during which you > were a pregnant man, a 300 foot tall alien or you were challenging > others to dunk a basketball. I'd say that game playing is one of your > favorite things. Wow, what a memory. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 223430 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> Message-ID: <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Date: Tue, 11 Apr 2006 04:08:34 GMT Gene Fuller wrote: > The question is what happens to the 75 degrees that was formerly > represented by the now-replaced wire. The coil may offer about 10 degrees. > I believe that Tom is stating that 75 is not equal to 10. Sounds like a > reasonable statement to me. No argument from me. Obviously you didn't understand my previous explanation that a resonant mobile antenna doesn't have to be 90 degrees long - something I explained weeks ago. Therefore, the coil doesn't have to be 75 degrees. Please re-read my postings again below until you understand what I said. Think of all the possibilities that make (Vfor+Vref)/(Ifor+Iref) purely resistive without any one of those terms being in phase with any other of those terms. Then you will realize why that mobile antenna is probably not 90 degrees long at all. In my earlier posting, I gave values of phase that make the feedpoint purely resistive without any one of those terms being in phase with any other one of those terms. BOTTOM LINE: Until you can prove that a mobile antenna is 90 degrees long, your argument is just another straw man. What is it about my following previous statements that you don't understand? > W5DXP wrote: >> You are confused. Some time ago, I explained why a mobile antenna >> may not be 90 degrees long at all. Did you understand that posting? >> All we can say is that (Vfor+Vref)/(Ifor+Iref) is purely resistive. >> We don't know how many degrees the reflected wave has traveled in >> its round trip because there are too many variables. >> So please stop the diversions. I have always said that the delay >> through a coil *IS WHAT IT IS* but it is NOT zero and it is not the >> 3 nS measured by W8JI for that 100 uH coil. It is also not the near-zero >> phase shift measured by W7EL using standing wave current phase as the >> reference. You, yourself, implied that is an invalid measurement when >> you told us there is no phase information in standing wave phase. >> >> Seems to me you are making my argument for me and that your real >> argument is with the other side. Have you told W7EL that standing >> wave current phase cannot be used to measure the delay through a >> coil? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223431 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Mon, 10 Apr 2006 23:00:40 -0500 Message-ID: <17929-443B29E8-742@storefull-3255.bay.webtv.net> References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> Tom, W8JI wrote: "Wave theory is just fine, but it has to be understood it is just a modeling shortcut and the results cannot conflict with the basic laws of physics," The Quantum theory may replace the wave theory some day, but the wave theory has always satisfied my needs. Terman writes on page 84 of his 1955 edition: "The quantity aq. rt. of ZY is called the propagation constant of the line. It is a complex quantity, having a real part alpha called the attenuation constant and an imaginary part beta termed the phase constant." On the next page 85, Terrman has diagrams showing behavior of the voltages of the incident and reflected waves on a transmission line. It is the same as that on antennas. That`s why the antenna section of Terman`s book tells the reader to refer to the transmission line chapter for the behavior of antennas. It`s identical. I`ve erected and operated countless rhombics in the international broadcasting service. I`ve underloaded them and overloaded them and in the process melted plenty of dissipation lines. I can attest that Terman has it right. Sometimes you have to do what you`ve got to do even when you know better. When the dissipation line went away we would cover outh America as well as Central Europe and get lots of fan mail for our troubles. We shouldn`t have been getting fan mail from South America but lots of Central Europeans were living there as refugees from the Axis and from the Allies. When we covered South America, some broadcaster with a valid claim on the frequency at that hour and place was being clobbered by us.. We couldn`t help it. Our job was to save the world and we did it while sometimes stepping on others in the process. I guarantee we never put anything even close to 100KW into a dissipation line. Problem was the Signal Corps rhombic kits were maxed out at 5 KW and it took time to get bigger resistance wire. 100 KW in a dissipation line would have melted it in days if not sooner. As it was, standard G.I. lines lasted weeks while glowing a cheerful red and did not erupt in a blinding flash. The wave travels along both wires simultaneously. The wires in the dissipation line melt at the input end not at the far end where the wire is smaller. Current does not travel through the line like the utility power frequency through a string of Christmas tree lights. Tom needs to get with the reality of the program. His idea is seriously flawed. Best regards, Richard Harrison, KB5WZI Article: 223432 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> Message-ID: Date: Tue, 11 Apr 2006 11:40:18 GMT Richard Harrison wrote: > Tom, W8JI wrote: > "Wave theory is just fine, but it has to be understood it is just a > modeling shortcut and the results cannot conflict with the basic laws of > physics," > > The Quantum theory may replace the wave theory some day, but the wave > theory has always satisfied my needs. W8JI is confused above. Wave theory, i.e. the distributed network model, is not much of a modeling shortcut. The lumped-circuit model is the actual shortcut and is a subset of the distributed network model. The lumped-circuit model conflicts much more with Maxwell's laws than does the distributed network model which conflicts hardly at all. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223433 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144747784.967613.137090@v46g2000cwv.googlegroups.com> Message-ID: Date: Tue, 11 Apr 2006 12:08:55 GMT w8ji@akorn.net wrote: > I take it you are saying you think current can flow two directions at > the same instant of time in a conductor, can be "lost" from a single > conductor through radiation and resistance without a shunting > impedance, conservation of charge isn't important, and Maxwell's > equations are wrong. EM energy is certainly flowing in two directions because it is a standing wave antenna. The forward current phasor is proportional to the forward H-field. The reflected current phasor is proportional to the reflected H-field. The two H-fields are superposed. That is the same thing as adding the two current phasors. Quoting Balanis: "Standing wave antennas, such as the dipole, can be analyzed as traveling wave antennas with waves propagating in opposite directions (forward and backward) and represented by traveling wave antenna currents I(f) and I(b)." W8JI says an antenna cannot be analyzed in that way. Who are we to believe? Balanis or W8JI? Balanis gives us permission to analyze two currents flowing in opposite directions at the same time. After all, the superposition principle allows us to do that. I'm sure Dr. Balanis would like to hear your argument to the contrary. Kraus agrees with Balanis and disagrees with you. "A sinusoidal current distribution may be regarded as the standing wave produced by two uniform (unattenuated) traveling waves of equal amplitude moving in opposite directions along the antenna." W8JI says it cannot be regarded in such terms. Who are we to believe? Kraus or W8JI? > ... can be "lost" from a single > conductor through radiation and resistance without a shunting > impedance, conservation of charge isn't important, and Maxwell's > equations are wrong. All we are saying is that the currents drops the same percentage amount as does the voltage. Voltage and current share the same identical attenuation factor. The E-field and H-field drop by the same percentage. If your model absolutely requires a shunt impedance, it can be found in the distributed LCLCLCLCLC model of a transmission line. Conservation of charge and conservation of energy are inviolate. Maxwell's equations, as opposed to the flawed lumped-circuit model, are correct. The distributed network model is a lot more like Maxwell's equations than is the lumped-circuit model. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223434 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 12:55:51 GMT Cecil Moore wrote: > Gene Fuller wrote: > >> The question is what happens to the 75 degrees that was formerly >> represented by the now-replaced wire. The coil may offer about 10 >> degrees. > > >> I believe that Tom is stating that 75 is not equal to 10. Sounds like >> a reasonable statement to me. > > > No argument from me. Cecil, Does that end the thread? Or do you plan to keep expanding into unknown territory where only your strawman lives? 73, Gene W4SZ Article: 223435 of rec.radio.amateur.antenna From: "Peter O. Brackett" References: Subject: Re: Gamma. Before somebody tells me. Message-ID: Date: Tue, 11 Apr 2006 13:16:33 GMT Reg et al: [snip] > The reason why both programs stop at 200 KHz has nothing to do with > the foregoing. It is due to skin effect not being fully operative at > lower frequencies which complicates calculations. > There are other programs which go down to audio and power frequencies. > ---- > Reg, G4FGQ [snip] It's a pity that your programs don't work all the way down to DC. Maxwell's celebrated [I really should say Heaviside's] equations do! Aside: It is Heaviside's vector formulation of Maxwell's complicated quaternic formulation with which most of we [modern] "electricians" are most familiar. In fact the common/conventional mathematical formulation of the reflection coefficient rho and its' magnitude gamma as derived from the Maxwell/Heaviside equations are indeed valid from "DC to daylight". Notwithstanding the views of some, there are indeed "reflected waves" at DC and even these "DC reflections" are correctly predicted by the widely accepted and celebrated common/conventional mathematical models of electro-magnetic phenomena, formulated by Maxwell and Heaviside. Reg I assume the reason for your programs failure to give [correct] answers below 200 kHz is because your "quick and dirty" programs do not utilize full mathematical models for skin effect below 200 kHz. As you know, solving Maxwell's equations for analytical solutions of practical problems is fraught with great difficulties and so often numerical techniques [MoM, FEM, etc...] or empirical parametric methods are used. Most [non-parametric] analytic skin effect models derived from Maxwell and Heaviside's equations [such as those in Ramo and Whinnery] involve the use of "transcendental" functions that although presented in a compact notation, even still do not succumb to "simple" evaluation. Surely though skin effect is easier to model below 200 kHz where the effect becomes vanishingly smaller? And so I don't understand why your programs cannot provide skin effects below 200 kHz. If you are interested I can point you to some [lumped model] skin effect models for wires [based upon concentric ring/cylindrical models] that, although parametric and empirical, are very "compact" and easly evalutate and which closely model skin effect, and other secondary effects such as "proximity crowding", up to prescribed frequency limits as set by the "parameters". These models simply make empirical parametric corrections to the basic R-L-C-G primary parameters by adding a few correction terms. Thoughts, comments? -- Pete k1po Indialantic By-the-Sea, FL Article: 223436 of rec.radio.amateur.antenna From: "Peter O. Brackett" References: <74ac6$44347c7f$45011502$11431@KNOLOGY.NET> <12390ho8oit9539@corp.supernews.com> <1239dl1litgdfc5@corp.supernews.com> <970b1$4435036d$45011502$7643@KNOLOGY.NET> <123jk90b36oii42@corp.supernews.com> Subject: Re: Transforner Theory Message-ID: Date: Tue, 11 Apr 2006 13:25:04 GMT Roy: Yes, that's why "gapped" cores must be used for precision [inductance] work. The properties of the basic core materials are too difficult to control during manufacture and hence result in manufactured pieces of wide variability. In addition the basic core material properties exhibit a wide variation under environmental variations such as temperature, pressure, etc... Inserting an accurately calibrated air gap in the magnetic path, by grinding the pot core center posts to a specific Al or alpha, accurately regulates the overall reluctance of the magnetic path and overcomes both of these variable effects, it alsow and allows the engineering of high performance "precision" inductors. In addition the air gap also mitigates a lot of the non-linear effects noted at higher levels of flux density. Gapped cores are "de riguer" for precision work. Ungapped cores are only used for "sloppy" inductance work. This includes many applications of transformers as well. -- Pete k1po Indialantic By-the-Sea, FL "Roy Lewallen" wrote in message news:123jk90b36oii42@corp.supernews.com... > It's been quite a few years now, so things might have changed. But some > time back I learned a bit about the ferrite manufacturing process. It > turns out that the green ceramic shrinks by something like 20 or 25 > percent during the firing process, with poor control over the amount of > shrinkage. The gaps in gapped pot cores, I found, were only nominally the > specified gap width -- each pot core was individually ground to meet the > Al specification, not some specification on air gap size. This isn't > important in using them, but I found it interesting. > > What you get with an air gap in trade for effective permeability, is much > greater independence of Al from the core characteristics (material > permeability and physical size) and therefore much greater stability with > regard to temperature and flux density, and much greater flux density > capability. > > Roy Lewallen, W7EL > > Peter O. Brackett wrote: >> Inductance core fans: >> >> [snip] >>> PS. interesting how pot cores have very little inductance change with >>> changing gausse. >> [snip] >> >> Most, if not all, pot cores used for "precision" inductors and >> transformers come in matched pairs with a very accurately ground narrow >> air gap between the two center posts. The Al (or alpha from some mfgs) >> is accurately set by the width of the air gap as ground during >> manufacture. The air gap also forms a large part of the overall magnetic >> path (air having a much larger reluctance than the ferrite). Such pot >> cores for precision inductors usually have an adjustable slug (set with a >> non magnetic screwdriver) to allow the finally assembled inductor to be >> set to an "exact" value. >> >> And so... pot cores intended for use in making precision inductors (as in >> filters or delay equalizers) or precision transformer applications >> exhibit little change in inductance over a wide range of conditions >> simply because of the air gap. >> >> -- >> Pete k1po >> Indialantic By-the-Sea, FL Article: 223437 of rec.radio.amateur.antenna From: "Ken Bessler" Subject: Yet another microwave question Message-ID: Date: Tue, 11 Apr 2006 08:43:37 -0500 I'm upgrading my laptop's antennas to 15" long 7dbi gain monsters (2). I don't have the materials (connectors) to do the job right so in true ham fashion, I cobbled up a solution: I have a 1.37mm od 50 ohm feedline (excellent quality) going up the back of my screen. Currently I have the braid/center separated at the end and soldered to my antennas. The new antennas have rp-tnc connectors and I don't have the proper bulkhead connectors for them. I found that a spare component (barrel diode) lead is a nice press fit for not only the center socket on the antenna but also for the shield so I plan on inserting the wire where it goes and soldering the coax to the wires. This will result in 2mm of distance between where the coax is stock (unseperated) and the new antennas' rp-tnc connector. Now - if I used bulkhead solder rp-tnc connectors, I don't think I could get that 2mm any smaller. As a matter of fact, I suspect, looking at Amphenol's specs, the new distance where the coax is separated would be greater. I can find no rp-tnc connectors for my micro coax so that's out. I've got to solder. I've seen many examples of where feedline is fed to a bulkhead connector like this, and sometimes they have 12mm of separated line but that was in a VHF application. So my question is this: If I keep my separated coax run (between the end of the coax and the rp-tnc antenna connector) to 2mm or less, what will that do as an impedance bump or otherwise at 2412 mhz? How critical is it at these freqs? Thanks for the help! -- 73's de Ken KG0WX - Kadiddlehopper #11808, Flying Pigs #-1055, Grid EM17io, Elecraft K2 #4913, XG2, 4SQRP Tenna Dipper, Heath GD-1B, MP-1(X)antenna Article: 223438 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 13:57:30 GMT Gene Fuller wrote: > Does that end the thread? Does agreeing that 75 is not equal to 10 end the thread? Of course not. That posting *ASSUMED FOR THE SAKE OF DISCUSSION* that EZNEC was reporting the actual delay through the coil. I suspect it is not reporting the actual delay because reflections are still present inside the coil. The characteristic impedance changes abruptly at the top of the coil so that would be no surprise at all. We know EZNEC blindly reports the net current that is there. If we, as modelers, don't eliminate reflections, EZNEC will not correctly report the traveling wave phase shift. In our naivete', we didn't eliminate reflections. 75 degrees is probably not correct. 10 degrees is probably not correct. Why do you want to quit before the correct answer has been found? *************************************************** Here's a more valid procedure for determining the delay through a coil. Changing nothing except the number of turns, add turns until the coil is self- resonant at the frequency of use. Frequency doesn't change. Coil diameter doesn't change. Turns per inch doesn't change. The *ONLY* thing that changes is the length of the coil. At self-resonance, we *know* the longer coil is 90 degrees long. *************************************************** Take that same 32 turn coil and keeping everything the same, add turns to the coil until it is self-resonant. We haven't changed the frequency, the diameter, or the turns per inch. All we have done is add 37 turns to the original 32 turn coil to make the self-resonant frequency equal to 4 MHz with 69 turns. SINCE WE HAVEN'T CHANGED THE FREQUENCY, WE KNOW THAT THE VELOCITY FACTOR OF THE COIL HAS NOT CHANGED. In the velocity factor equation, the only variables are coil diameter, turns per inch, and wavelength. NONE OF THOSE VARIABLES ARE CHANGED ABOVE. So we know that 69 turns makes that coil stock self-resonant at 4 MHz. That would make the phase shift through 32 turns equal to 42 degrees, making our above 10 degree assumption false. 42 degrees is probably fairly close to the actual value. The velocity factor for that coil stock calculates out to be 0.023 on 4 MHz. The delay through a coil is what it is. The only valid side to this argument are technical facts, valid measurements, and valid modeling. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223439 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> Message-ID: <4HO_f.10160$4L1.3757@newssvr11.news.prodigy.com> Date: Tue, 11 Apr 2006 14:03:44 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> I've said it before and I'll say it again, there is no phase variable >> in I1*cos(kx+wt) and there is no phase variable in I1*cos(kx-wt) so >> there can't possibly be any phase information in 2*I1*cos(kx)*cos(wt). > > > Sorry, you are wrong about that. EZNEC reports that phase information. > Assuming the EZNEC default convention, the source is 1.0 amp at zero > degrees at t=0. So the RMS value of the traveling wave current is > 1.0 amp at -'kx' degrees. -'kx' *IS* the phase angle of the current > up and down the wire referenced to the source. It is negative because > the source naturally leads the traveling wave. > > Note 'kx' is how far the point of interest is away from the source > in degrees. > > Doesn't anyone understand phasors anymore? You missed the point again, Cecil. Carry on. 73, Tom Donaly, KA6RUH Article: 223440 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 08:56:53 -0500 Message-ID: <2025-443BB5A5-730@storefull-3252.bay.webtv.net> References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> Tom, W8JI wrote: "I take it you are saying you think current can flow two directions at the same instant of time in a conductor through radiation and resistance without a shunting impedance, conservation of charge isn`t important, and Maxwell`s equarions are wrong." That`s the wrong take. Maxwell works for me even if there is no aether. Anntennas work in free space without a ground but it is hard to duplicate free space conditions at high and lower frequencies here on earth. Every standing-wave antenna has a reflection caused by an impedance discontinuity at wire`s end. At this point, a reflection begins its travel back toward the generator. By the time the reflection arrives at the generator, every point on the wire has current flowing in both directions simultaneously. No shunting capacitance to earth or anyplace else is needed to conserve charge. The wire is self-sufficient. Radiation resistance is a convenience defined as the resistance which if placed in series with an antenna would consume the same power that the antenna is radiating. At every point along an antenna with a reflection, current is flowing in two directions at the same time. Best regards, Richard Harrison, KB5WZI Article: 223441 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> <4HO_f.10160$4L1.3757@newssvr11.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 14:14:35 GMT Tom Donaly wrote: > Cecil Moore wrote: >> Doesn't anyone understand phasors anymore? > > You missed the point again, Cecil. Carry on. The point is that there is phase information in the traveling wave equation. -'kx' *IS* the phase and is reported by EZNEC at: http://www.qsl.net/w5dxp/travstnd.GIF -- 73, Cecil http://www.qsl.net/w5dxp Article: 223442 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> Message-ID: Date: Tue, 11 Apr 2006 15:34:37 GMT Richard Harrison wrote: > Tom, W8JI wrote: > "I take it you are saying you think current can flow two directions at > the same instant of time in a conductor through radiation and resistance > without a shunting impedance, conservation of charge isn`t important, > and Maxwell`s equarions are wrong." > > That`s the wrong take. > > Maxwell works for me even if there is no aether. > > Anntennas work in free space without a ground but it is hard to > duplicate free space conditions at high and lower frequencies here on > earth. > > Every standing-wave antenna has a reflection caused by an impedance > discontinuity at wire`s end. At this point, a reflection begins its > travel back toward the generator. By the time the reflection arrives at > the generator, every point on the wire has current flowing in both > directions simultaneously. No shunting capacitance to earth or anyplace > else is needed to conserve charge. The wire is self-sufficient. > > Radiation resistance is a convenience defined as the resistance which if > placed in series with an antenna would consume the same power that the > antenna is radiating. > > At every point along an antenna with a reflection, current is flowing in > two directions at the same time. > > Best regards, Richard Harrison, KB5WZI > Completely wrong, as usual. There is nothing in the natural world that can double itself and go two opposite directions at the same time. In order to do so it would have to violate the principle of the conservaton of charge. At any instant, the charge at a point has to be going either one direction or another which you can confirm using the wave equation which Cecil doesn't understand any more than you do. Superposition is a fine principle, but like any intellectual tool it has to be understood to be used properly. 73, Tom Donaly, KA6RUH Article: 223443 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> <4HO_f.10160$4L1.3757@newssvr11.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 15:36:02 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> Cecil Moore wrote: >> >>> Doesn't anyone understand phasors anymore? >> >> >> You missed the point again, Cecil. Carry on. > > > The point is that there is phase information in the > traveling wave equation. -'kx' *IS* the phase and > is reported by EZNEC at: > http://www.qsl.net/w5dxp/travstnd.GIF You still don't get it. 73, Tom Donaly, KA6RUH Article: 223444 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <2JidnXYWTozFHKTZ4p2dnA@adelphia.com> Subject: Re: Counterpoise wire length Message-ID: Date: Tue, 11 Apr 2006 11:41:13 -0400 If you are using long wire for different bands, you can tap to your water pipe for ground, or metal frame of the screen door, or most likely your RX is already "grounded" through its AC PS. You can try through capacitor of about 10000 uuF/1kV from your RX ground to your ground pin the AC outlet. Alternative I used for antenna when in restricted area, just run wire from ant terminal on RX through capacitor of about 10 k rated at least at 3000V to one of the connections in AC outlet, well insulated and mounted in AC plug. Yuri, K3BU "Harbin" wrote in message news:HoudnfaEKJUN-6bZRVn-ug@adelphia.com... > Say I was using a short wave receiver, and I'm on the second floor, > without a good > ground. I would be running a long wire. Would it help to cut a > counterpoise for the > bands I wish to listen to, a single wire for each band? Would it be 1/4, > or 1/2 wave? > > -- > SeeYaa:) Harbin Osteen KG6URO > Article: 223445 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144747784.967613.137090@v46g2000cwv.googlegroups.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Tue, 11 Apr 2006 12:15:04 -0400 Richard H., He is stuck on DC in a coil. Tom did not discover Standing Waves, Impedances, Currents, Voltages in RF circuits, antennas, feedlines. Helooooo! IT'S RF and standing waves along the resonant antenna and things to do with RF energy along them radiators, like sin and cos distribution of voltage and current. Which show that current and voltage can be ZERO along the conducting wire, aka antenna. First he used Kirchoff, now is Maxwell to the "rescue" to muddy the waters. Maybe we should apply for him for vanity callsign WR0NG :-) Yuri, K3BU wrote in message news:1144747784.967613.137090@v46g2000cwv.googlegroups.com... > Richard Harrison wrote: > >> The wave travels along both wires simultaneously. The wires in the >> dissipation line melt at the input end not at the far end where the wire >> is smaller. Current does not travel through the line like the utility >> power frequency through a string of Christmas tree lights. >> >> Tom needs to get with the reality of the program. His idea is seriously >> flawed. > > I take it you are saying you think current can flow two directions at > the same instant of time in a conductor, can be "lost" from a single > conductor through radiation and resistance without a shunting > impedance, conservation of charge isn't important, and Maxwell's > equations are wrong. > > You know that because you installed antennas at one point in your life. > Is that correct or did I misunderstand your post? > > 73 Tom > Article: 223446 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 12:23:25 -0500 Message-ID: <25827-443BE60D-679@storefull-3257.bay.webtv.net> References: Tom Donaly, KA6RUH wrote: "There is nothing in the natural world that can double itself and go in the opposite direction at the same time." Watch water waves slam into a bulkhead and you can see the reflected waves interfere with the incident waves as they travel in the opposite directions. Electrical waves, incident and reflected, pass through each other too. In the antenna or transmission line, the charge is impelled by the energy supplied by the generator to move back and forth on the surface of the wire at the radio frequency rate. The incident wave and the reflected wave on a transmission line travel in opposite directions. At certain points along the line the voltages in the waves will be in phase and will add, while in other points they will be out of phase and subtract. The points along the line where the two voltages are in phase are points of maximum voltage and minimum current and are spaced one half wavelength apart. The points along the line where the two voltages are 180-degrees out of phase are points of minimum voltage and maximum current and are also one half wavelength apart. The distance between alternate points is one-quarter wavelength. The reflection of a radio wave is a natural occurrence. When the voltage produced by the incident wave hits the open-circuit of a wire it doubles itself and starts a wave propagating in the opposite direction while the incident waves are yet arriving at the open-circuit. Best regards, Richard Harrison, KB5WZI Article: 223447 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 12:37:32 -0500 Message-ID: <123nqbaj6mh2q47@corp.supernews.com> References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> Tom Donaly wrote: > Richard Harrison wrote: > >> Tom, W8JI wrote: >> "I take it you are saying you think current can flow two directions at >> the same instant of time in a conductor through radiation and resistance >> without a shunting impedance, conservation of charge isn`t important, >> and Maxwell`s equarions are wrong." >> >> That`s the wrong take. >> >> Maxwell works for me even if there is no aether. >> >> Anntennas work in free space without a ground but it is hard to >> duplicate free space conditions at high and lower frequencies here on >> earth. >> >> Every standing-wave antenna has a reflection caused by an impedance >> discontinuity at wire`s end. At this point, a reflection begins its >> travel back toward the generator. By the time the reflection arrives at >> the generator, every point on the wire has current flowing in both >> directions simultaneously. No shunting capacitance to earth or anyplace >> else is needed to conserve charge. The wire is self-sufficient. >> >> Radiation resistance is a convenience defined as the resistance which if >> placed in series with an antenna would consume the same power that the >> antenna is radiating. >> >> At every point along an antenna with a reflection, current is flowing in >> two directions at the same time. >> >> Best regards, Richard Harrison, KB5WZI > > > Completely wrong, as usual. There is nothing in the natural world > that can double itself and go two opposite directions at the same > time. In order to do so it would have to violate the principle of > the conservaton of charge. At any instant, the charge at a point > has to be going either one direction or another which you can > confirm using the wave equation which Cecil doesn't understand > any more than you do. Superposition is a fine principle, but > like any intellectual tool it has to be understood to be used > properly. > 73, > Tom Donaly, KA6RUH Tom Have you ever sloshed water in a bowl? If you had you would have seen wave forms going in both directions. First the initial wave crosses the bowl then reflects off the side of the bowl and returns in the opposite direction. This is the same as an EMF wave in an antenna. No violation of any principles of conservation, in fact it is demanded of the principle. Dave WD9BDZ Article: 223448 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 17:38:21 GMT Cecil Moore wrote: > > Here's a more valid procedure for determining the > delay through a coil. Cecil, So you think adding turns to a coil is a nice linear process that allows you to then subdivide the resonance effects according the number of turns in each subsection? That's a good one. I almost injured myself laughing when I read it. 73, Gene W4SZ Article: 223449 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Gamma. Before somebody tells me. Date: Tue, 11 Apr 2006 10:42:41 -0700 Message-ID: <123nqkkt9q5t860@corp.supernews.com> References: Peter O. Brackett wrote: > . . . > Most [non-parametric] analytic skin effect models derived from Maxwell and > Heaviside's equations [such as those in Ramo and Whinnery] involve the use > of "transcendental" functions that although presented in a compact notation, > even still do not succumb to "simple" evaluation. > > Surely though skin effect is easier to model below 200 kHz where the effect > becomes vanishingly smaller? And so I don't understand why your programs > cannot provide skin effects below 200 kHz. > > If you are interested I can point you to some [lumped model] skin effect > models for wires [based upon concentric ring/cylindrical models] that, > although parametric and empirical, are very "compact" and easly evalutate > and which closely model skin effect, and other secondary effects such as > "proximity crowding", up to prescribed frequency limits as set by the > "parameters". > > These models simply make empirical parametric corrections to the basic > R-L-C-G primary parameters by adding a few correction terms. > > Thoughts, comments? Calculation of skin effect in a round wire is simple, provided that you have the ability to calculate various Bessel functions. Libraries in Fortran are widely available, and probably in other languages also. NEC-2 (and therefore EZNEC) does such a full calculation for evaluation of wire loss. A side benefit of doing this is that you also get an accurate evaluation of the internal inductance. However, in practical terms, you can do quite well with the common skin depth approximation based on the assumption that the wire diameter is at least several skin depths, and an interpolation from there to the DC case. Coaxial cable is more problematic than twinlead. Most analyses assume that the resistance of the shield is negligible. But for an accurate evaluation, you need to include it. At high frequencies it's simple, but it's much more difficult at low frequencies than for a round wire, since most equations you'll find require subtracting huge numbers from each other, exceeding the capability of even double precision on modern PCs. It's possible but requires some mathematical manipulation and trickery. With coax at low frequencies, the fields from the two conductor currents reach the outside of the cable. While they should still cancel, this might cause some problems with the assumptions we normally make in the analysis of coaxial transmission lines. You're not likely to be able to do a very good job of predicting real life transmission line behavior in any case, though, unless you account for such real factors as the roughness of stranded conductors, braided coax shield, and plated conductors. I'd also expect twinlead with solid or punched polyethylene insulation between conductors to be somewhat dispersive (that is, having a velocity factor which changes with frequency), but I've never tried to measure it. Reg has said he's measured many pieces of real cable and found its loss to agree with his earlier coax program, but won't tell us where he buys it. Everything I've ever been able to buy is considerably lossier. Roy Lewallen, W7EL Article: 223450 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> Message-ID: Date: Tue, 11 Apr 2006 17:57:40 GMT Tom Donaly wrote: > There is nothing in the natural world > that can double itself and go two opposite directions at the same > time. Seems your ignorance also extends to entangled particles? > In order to do so it would have to violate the principle of > the conservaton of charge. This is simply one more example of the seduction of other- wise intelligent people by the lumped-circuit model's unproven presuppositions. You are confusing charge with EM wave energy. If two EM light waves traveling in opposite directions can cause a standing wave in empty space, then so can two RF waves traveling in opposite directions in space or around a wire. There is no requirement for current at all. Current is a left over artifact from the DC model. In fact, it can be proven that virtually all of the energy (power) exists solely in the two EM waves surrounding the wire and virtually none in the conductor. All that is required for standing waves is E-fields and H-fields traveling in opposite directions WHETHER A WIRE EXISTS OR NOT. If everyone were using Maxwell's equations instead of flawed simplified models, none of this confusion would exist. All of the energy is in the waves and none in the current or voltage. After all, E x H is the *total power* in a wave. There is no extra energy left over to support voltage and current. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223451 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> <123nqbaj6mh2q47@corp.supernews.com> Message-ID: Date: Tue, 11 Apr 2006 17:58:07 GMT David G. Nagel wrote: > > Tom > > Have you ever sloshed water in a bowl? If you had you would have seen > wave forms going in both directions. First the initial wave crosses the > bowl then reflects off the side of the bowl and returns in the opposite > direction. > This is the same as an EMF wave in an antenna. No violation of any > principles of conservation, in fact it is demanded of the principle. > > Dave WD9BDZ Dave, You have highlighted a misconception that is common and a great cause of confusion in this forum. Yes, the "waves" can do what you say. However, the "waves" are merely mathematical descriptions of the underlying physical phenomena. There is simply no such thing as a "wave" all by itself. Instead there are water waves, electromagnetic field waves, guitar string waves, sound waves, and so on. Nature tends to be single valued, at least in the ordinary classical world. At any specific point in time and space there is only one value of current, one value of electric field, one value for the motion of a particle (water molecule, guitar string molecule, etc.), one charge density, and so on. These values can and do change with differences in time and space. However, the physical entities do not have two values at once in the same time and place. 73, Gene W4SZ Article: 223452 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> <4HO_f.10160$4L1.3757@newssvr11.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 17:58:53 GMT Tom Donaly wrote: > You still don't get it. And you still haven't posted any technical information to contradict the technical information that I am posting. One wonders why? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223453 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> Message-ID: Date: Tue, 11 Apr 2006 18:06:11 GMT Cecil, Are you practicing your stand-up comedy routine? You are in rare form today. Why didn't you set us straight about 3000 messages ago? If only we knew that RF current was a mere artifact we could have shortened this thread to one message. 73, Gene W4SZ Cecil Moore wrote: > > You are confusing charge with EM wave energy. If two EM light > waves traveling in opposite directions can cause a standing > wave in empty space, then so can two RF waves traveling in > opposite directions in space or around a wire. There is no > requirement for current at all. Current is a left over > artifact from the DC model. In fact, it can be proven > that virtually all of the energy (power) exists solely in > the two EM waves surrounding the wire and virtually none in > the conductor. All that is required for standing waves is > E-fields and H-fields traveling in opposite directions WHETHER > A WIRE EXISTS OR NOT. > > If everyone were using Maxwell's equations instead of flawed > simplified models, none of this confusion would exist. All > of the energy is in the waves and none in the current or > voltage. After all, E x H is the *total power* in a wave. > There is no extra energy left over to support voltage and > current. Article: 223454 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> Message-ID: Date: Tue, 11 Apr 2006 18:06:16 GMT K7ITM wrote: > Understanding the congrence among many methods/theories is a very nice > thing, for it gives one confidence that they are correct, and the > ability to apply the one that's most convenient to any particular > problem. I would not want to take away wave theory, or any other valid > theory, from you; I would only ask that you better understand that your > pet is not the ONLY valid explanation. The point is that in any disagreement between the lumped-circuit model and a properly applied distributed network model, the lumped-circuit model loses *EVERY* time since the lumped-circuit model is a *SUBSET* of the distributed network model. If your current charge concepts disagree with Maxwell's equations, Maxwell's equations win *EVERY* time. Maxwell's equations do not require individual charge carriers. They work just fine considering only fields in the aether. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223455 of rec.radio.amateur.antenna From: "Jerry Martes" References: <0g5og3-bsa.ln1@p400bob.personal.cox.net> <%3h_f.579$B42.454@dukeread05> <1144761195.925372.80250@j33g2000cwa.googlegroups.com> Subject: Re: 16 el coaxial colinear (2.4ghz) question - How 'bout this? Message-ID: <0iS_f.11270$gy2.9132@trnddc08> Date: Tue, 11 Apr 2006 18:10:04 GMT wrote in message news:1144761195.925372.80250@j33g2000cwa.googlegroups.com... > I tried to make the same antenna with 1/2" hardline & had several RF > analyzers to help me, it never worked out. This article helps > explain why coax wont work, I used wire and would my on coils for > phasing, i also took apart a Madrax antenna to get the measurements, > they used brass tubes inbetween the coils, not because its brass but so > the 1/2 wave length can be easily adjusted. > http://www.centurion.com/home/pdf/wp_omni_wireless.pdf Hi Tucker Thanks for reference to that great site. I really like that flat antenna. Jerry Article: 223456 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144774399.040450.55480@i39g2000cwa.googlegroups.com> Message-ID: <6yS_f.65011$H71.11431@newssvr13.news.prodigy.com> Date: Tue, 11 Apr 2006 18:27:14 GMT K7ITM wrote: > Could you please enlighten us, Cecil, exactly why you think that > anything in all of W8JI's full posting referenced by reference below > where he implicitly or explicitly says anything at all about a lumped > model, or about lumped behaviour? After a careful search, I'm unable > to find it. I only find a discussion of distributed behaviour in a > circuit which extends beyond near field. W8JI is right 99% of the time. I agree with him on those things as do you. Your above posting is no surprise. Here's one of W8JI's statements. Please defend it. >W8JI said: > > Radiation does not cause current taper. Dissipation does not either. What is contained in the attenuation factor for the current transmission line equation if not radiation and dissipation? What else is there? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223457 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 18:30:53 GMT Gene Fuller wrote: > So you think adding turns to a coil is a nice linear process that allows > you to then subdivide the resonance effects according the number of > turns in each subsection? That appears to me to be the most valid measurement that we can make of the delay through a coil. If you have a better way, please present it. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223458 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> <123nqbaj6mh2q47@corp.supernews.com> Message-ID: <2GS_f.65013$H71.23871@newssvr13.news.prodigy.com> Date: Tue, 11 Apr 2006 18:35:42 GMT Gene Fuller wrote: > ... one value for the motion of a particle ... Now I know you are pulling our legs. We are talking about *electrons*, Gene, you know that "particle" capable of going through two slits at the same time and interferring with itself on the other side? Please pick out just one electron and tell us what is its position and velocity. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223459 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> Message-ID: <7KS_f.65014$H71.41009@newssvr13.news.prodigy.com> Date: Tue, 11 Apr 2006 18:40:03 GMT Gene Fuller wrote: > Why didn't you set us straight about 3000 messages ago? If only we knew > that RF current was a mere artifact we could have shortened this thread > to one message. Well Gene, that fact didn't occur to me 3000 messages ago so I recently corrected my mistaken concepts. What do you do when you discover a mistaken concept of your own? (rhetorical question) Truth is, I'm still learning. How about you? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223460 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 13:35:39 -0500 Message-ID: <2026-443BF6FB-170@storefull-3252.bay.webtv.net> References: Gene, W4SZ wrote: "However, the physical entities do not have two values at once in the same time and place." You can measure each of the two simultaneous constituents with the right equipment. A Bird Thruline wattmeter uses a directional coupler to separate forward direction power from reverse direction power. These are obbtainable at the same time and place anywhere in a 50-ohm coax line. Individual volts and amps in each direction are easily calcuable from the powers indicated in each direction. Best regards, Richard Harrison, KB5WZI Article: 223461 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 19:22:15 GMT Cecil Moore wrote: > Gene Fuller wrote: > >> So you think adding turns to a coil is a nice linear process that >> allows you to then subdivide the resonance effects according the >> number of turns in each subsection? > > > That appears to me to be the most valid measurement that we > can make of the delay through a coil. If you have a better > way, please present it. Cecil, C'mon, you know as well as anybody that inductance of a coil tends to increase as n-squared. Yes, there are all kinds of special cases and correction factors. Adding turns and then pretending everything is nice and linear, thereby allowing decomposition into subcomponents, is just plain silly. 73, Gene W4SZ Article: 223462 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <2026-443BF6FB-170@storefull-3252.bay.webtv.net> Message-ID: Date: Tue, 11 Apr 2006 19:23:54 GMT Richard Harrison wrote: > Gene, W4SZ wrote: > "However, the physical entities do not have two values at once in the > same time and place." > > You can measure each of the two simultaneous constituents with the right > equipment. A Bird Thruline wattmeter uses a directional coupler to > separate forward direction power from reverse direction power. These are > obbtainable at the same time and place anywhere in a 50-ohm coax line. > Individual volts and amps in each direction are easily calcuable from > the powers indicated in each direction. > > Best regards, Richard Harrison, KB5WZI > Richard, You are in luck! This is Burger King day. Have it your way. 73, Gene W4SZ Article: 223463 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 14:28:05 -0500 Message-ID: <123o0qjhe6nst99@corp.supernews.com> References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> <123nqbaj6mh2q47@corp.supernews.com> Gene Fuller wrote: > David G. Nagel wrote: > >> >> Tom >> >> Have you ever sloshed water in a bowl? If you had you would have seen >> wave forms going in both directions. First the initial wave crosses >> the bowl then reflects off the side of the bowl and returns in the >> opposite direction. >> This is the same as an EMF wave in an antenna. No violation of any >> principles of conservation, in fact it is demanded of the principle. >> >> Dave WD9BDZ > > > > Dave, > > You have highlighted a misconception that is common and a great cause of > confusion in this forum. > > Yes, the "waves" can do what you say. However, the "waves" are merely > mathematical descriptions of the underlying physical phenomena. There is > simply no such thing as a "wave" all by itself. Instead there are water > waves, electromagnetic field waves, guitar string waves, sound waves, > and so on. > > Nature tends to be single valued, at least in the ordinary classical > world. At any specific point in time and space there is only one value > of current, one value of electric field, one value for the motion of a > particle (water molecule, guitar string molecule, etc.), one charge > density, and so on. These values can and do change with differences in > time and space. However, the physical entities do not have two values at > once in the same time and place. > > 73, > Gene > W4SZ Now if we can only convince certain other individuals of this maybe we can get back to something useful, such as how many angles can dance on the head of a pin. Dave WD9BDZ Article: 223464 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> <123nqbaj6mh2q47@corp.supernews.com> <2GS_f.65013$H71.23871@newssvr13.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 19:32:24 GMT Cecil Moore wrote: > Gene Fuller wrote: > >> ... one value for the motion of a particle ... > > > Now I know you are pulling our legs. We are talking about > *electrons*, Gene, you know that "particle" capable of > going through two slits at the same time and interferring > with itself on the other side? > > Please pick out just one electron and tell us what is > its position and velocity. Cecil, I think I specifically mentioned the "ordinary classical world", but I'll play along. Why don't you go ahead and measure that electron to prove that it goes through both slits at once? 8-) Article: 223465 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 14:39:35 -0500 Message-ID: <20544-443C05F7-661@storefull-3253.bay.webtv.net> References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> Gene, W4SZ wroyte: "However, the physical entities do not have two values at once in the same time and place." All that is needed to prove energy in the incident and reflected waves each has its own values is to separate the two with a directional coupler as the Bird Thruline wattmeter does. It gives you forward and reverse powers at the same place anywhere you choose along a transmission line. The standard device is calibrated for 50-ohm lines so it is easy to convert the power indicationsw to volts and amps if desired. Take what Tom, W8JI wrote today: "I take it you are saying you think current can flow in two directions at the same instant of time in a conductor, can be "lost" from a single conductor through radiation and resistance without a shunting impedance, conservation of chrge isn`t important and Maxwell`s equations are wrong." Of course, except for Maxwell! Maxwell`s equations work. Current can flow in opposite directions past a point. Shunting impedance makes a voltage divider with series impedance, but that`s not the only way to get a difference between points on a conductor or a coil. Conservation of charge isn`t an issue with r-f current in a wire or coil. Tom`s posting is nonsense. Best regards, Richard Harrison, KB5WZI Article: 223466 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> <123nqbaj6mh2q47@corp.supernews.com> Message-ID: Date: Tue, 11 Apr 2006 20:00:54 GMT David G. Nagel wrote: > Tom Donaly wrote: > >> Richard Harrison wrote: >> >>> Tom, W8JI wrote: >>> "I take it you are saying you think current can flow two directions at >>> the same instant of time in a conductor through radiation and resistance >>> without a shunting impedance, conservation of charge isn`t important, >>> and Maxwell`s equarions are wrong." >>> >>> That`s the wrong take. >>> >>> Maxwell works for me even if there is no aether. >>> >>> Anntennas work in free space without a ground but it is hard to >>> duplicate free space conditions at high and lower frequencies here on >>> earth. >>> >>> Every standing-wave antenna has a reflection caused by an impedance >>> discontinuity at wire`s end. At this point, a reflection begins its >>> travel back toward the generator. By the time the reflection arrives at >>> the generator, every point on the wire has current flowing in both >>> directions simultaneously. No shunting capacitance to earth or anyplace >>> else is needed to conserve charge. The wire is self-sufficient. >>> >>> Radiation resistance is a convenience defined as the resistance which if >>> placed in series with an antenna would consume the same power that the >>> antenna is radiating. >>> >>> At every point along an antenna with a reflection, current is flowing in >>> two directions at the same time. >>> >>> Best regards, Richard Harrison, KB5WZI >> >> >> >> Completely wrong, as usual. There is nothing in the natural world >> that can double itself and go two opposite directions at the same >> time. In order to do so it would have to violate the principle of >> the conservaton of charge. At any instant, the charge at a point >> has to be going either one direction or another which you can >> confirm using the wave equation which Cecil doesn't understand >> any more than you do. Superposition is a fine principle, but >> like any intellectual tool it has to be understood to be used >> properly. >> 73, >> Tom Donaly, KA6RUH > > > Tom > > Have you ever sloshed water in a bowl? If you had you would have seen > wave forms going in both directions. First the initial wave crosses the > bowl then reflects off the side of the bowl and returns in the opposite > direction. > This is the same as an EMF wave in an antenna. No violation of any > principles of conservation, in fact it is demanded of the principle. > > Dave WD9BDZ Tell me which of the water molecules moved in two opposite directions at the same time. The waves can move through each other in opposite directions, but their combined influence is what moves the water molecules. There are not two separate sets of water molecules that flow in opposite directions, either. It's the combined total of forces that causes the movement of both charge and water. Two opposite movements of either charge or water are impossible. 73, Tom Donaly, KA6RUH Article: 223467 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> Message-ID: <%ZT_f.67705$Jd.42796@newssvr25.news.prodigy.net> Date: Tue, 11 Apr 2006 20:05:15 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> There is nothing in the natural world >> that can double itself and go two opposite directions at the same >> time. > > > Seems your ignorance also extends to entangled particles? > >> In order to do so it would have to violate the principle of >> the conservaton of charge. > > > This is simply one more example of the seduction of other- > wise intelligent people by the lumped-circuit model's > unproven presuppositions. > > You are confusing charge with EM wave energy. If two EM light > waves traveling in opposite directions can cause a standing > wave in empty space, then so can two RF waves traveling in > opposite directions in space or around a wire. There is no > requirement for current at all. Current is a left over > artifact from the DC model. In fact, it can be proven > that virtually all of the energy (power) exists solely in > the two EM waves surrounding the wire and virtually none in > the conductor. All that is required for standing waves is > E-fields and H-fields traveling in opposite directions WHETHER > A WIRE EXISTS OR NOT. > > If everyone were using Maxwell's equations instead of flawed > simplified models, none of this confusion would exist. All > of the energy is in the waves and none in the current or > voltage. After all, E x H is the *total power* in a wave. > There is no extra energy left over to support voltage and > current. Cecil, if you knew what you were talking about you might be dangerous. 73, Tom Donaly, KA6RUH Article: 223468 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> <4HO_f.10160$4L1.3757@newssvr11.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 20:06:33 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> You still don't get it. > > > And you still haven't posted any technical information > to contradict the technical information that I am posting. > One wonders why? Cecil, when you post some technical information I'll respond appropriately. 73, Tom Donaly, KA6RUH Article: 223469 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 22:19:29 GMT Gene Fuller wrote: > Cecil Moore wrote: > >> Gene Fuller wrote: >>> So you think adding turns to a coil is a nice linear process that >>> allows you to then subdivide the resonance effects according the >>> number of turns in each subsection? >> >> That appears to me to be the most valid measurement that we >> can make of the delay through a coil. If you have a better >> way, please present it. > > C'mon, you know as well as anybody that inductance of a coil tends to > increase as n-squared. Yes, there are all kinds of special cases and > correction factors. Increasing the length of a coil or transmission line doesn't change its velocity factor at a fixed frequency. > Adding turns and then pretending everything is nice and linear, thereby > allowing decomposition into subcomponents, is just plain silly. Velocity factor is *nice* and linear, i.e. it is constant. Please stop these diversions. I'm sure you are not that ignorant. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223470 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> <1144784891.274341.118940@z34g2000cwc.googlegroups.com> Message-ID: Date: Tue, 11 Apr 2006 22:35:17 GMT K7ITM wrote: > So, PLEASE wake up and quit trying to attribute this "lumped circuit" > stuff, and the completely independent charge quantization stuff, to > this discussion. It simply is NOT there. It is absolutely NOT the > point of all this. I agree so please tell that to everyone who is defending the lumped circuit presuppositions. One cannot use the presuppositions of the lumped circuit model to prove those same presuppositions!!! > If your current charge concepts disagree with Maxwell's equations, > Maxwell's equations win *EVERY* time. Maxwell's equations do not > require individual charge carriers. They work just fine considering > only fields in the aether. And PLEASE wake up and quit screwing up the attributions on this newsgroup. You didn't say the above! I said the above. Why do you deliberately falsify the attributions? Such is illegal in Texas. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223471 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144747784.967613.137090@v46g2000cwv.googlegroups.com> <2025-443BB5A5-730@storefull-3252.bay.webtv.net> <123nqbaj6mh2q47@corp.supernews.com> Message-ID: <6dW_f.10283$4L1.2628@newssvr11.news.prodigy.com> Date: Tue, 11 Apr 2006 22:37:54 GMT Tom Donaly wrote: > Tell me which of the water molecules moved in two opposite directions > at the same time. The waves can move through each other in opposite > directions, but their combined influence is what moves the water > molecules. There are not two separate sets of water molecules that > flow in opposite directions, either. It's the combined total of > forces that causes the movement of both charge and water. Two opposite > movements of either charge or water are impossible. Nobody is arguing about that so it is obviously just a straw man. The real question is: Can two EM waves travel in opposite directions in free space or along a wire. The answer is YES!!! Standing waves can exist in free space or along a wire. To deny the existence of standing waves is ridiculous. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223472 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1LA_f.67482$Jd.18464@newssvr25.news.prodigy.net> <4HO_f.10160$4L1.3757@newssvr11.news.prodigy.com> Message-ID: Date: Tue, 11 Apr 2006 22:39:27 GMT Tom Donaly wrote: > Cecil, when you post some technical information I'll > respond appropriately. Here it is for the 20th time as reported by EZNEC. http://www.qsl.net/w5dxp/travstnd.GIF -- 73, Cecil http://www.qsl.net/w5dxp Article: 223473 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> <1144787795.664748.325710@z34g2000cwc.googlegroups.com> Message-ID: Date: Tue, 11 Apr 2006 22:44:03 GMT K7ITM wrote: > What should I do when I find that Maxwell's equations do NOT accurately > describe the observable situation, with observations that can be easily > repeated with the same results each time? You should find out what is wrong with those observations. Therefore, you should find out what is wrong with W8JI's and W7EL's measurements. > If your current charge concepts disagree with Maxwell's equations, > Maxwell's equations win *EVERY* time. Maxwell's equations do not > require individual charge carriers. They work just fine considering > only fields in the aether. Please cease and desist from attributing my postings to you, Tom. Such is illegal in Texas and probably also illegal in your state. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223474 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <2026-443BF6FB-170@storefull-3252.bay.webtv.net> <1144799035.064183.9530@v46g2000cwv.googlegroups.com> Message-ID: <3DX_f.67771$Jd.42885@newssvr25.news.prodigy.net> Date: Wed, 12 Apr 2006 00:13:51 GMT w8ji@akorn.net wrote: > I can place it in a system with NO standing waves and it will show > standing waves. I can place it in a system with standing waves and have > it show NO standing waves. It does not measure standing waves, it > simply measures the ratio and phase of voltage and current at one point > in the transmission line. Yes, but if it is calibrated for 50 ohms and installed in a 50 ohm environment, it is indeed accurately reporting forward and reflected power. It is accurately separating the forward wave energy from the reflected wave energy. If it weren't, Bird would be guilty of false advertising. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223475 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: <_PX_f.67778$Jd.47128@newssvr25.news.prodigy.net> Date: Wed, 12 Apr 2006 00:27:38 GMT John Popelish wrote: > Cecil Moore wrote: >> Increasing the length of a coil or transmission line doesn't >> change its velocity factor at a fixed frequency. > > That is an interesting hypothesis. Since I know you are going to nit-pick that statement, I probably should add "appreciably" in front of "change". :-) > How would you go about testing its validity? The velocity factor of a piece of transmission line doesn't change appreciably with length. The velocity factor of a straight wire doesn't change appreciably with length. I would think that a two wavelength coil would be approximately twice as long as a one wavelength coil which would be approximately twice as long as a 1/2 wavelength coil. The equation for the velocity factor of a coil depends upon: 1. The diameter of the coil 2. The number of turns per unit length 3. The frequency None of those factors are dependent upon the length of the coil. > (Have you heard of end effects?) Of course, it's the 5% difference between 468/f and 492/f. I'm not talking super accuracy here - just better accuracy than anyone has yet measured. It is akin to your suggestion that a coil be installed between two current nodes and its number of degrees calculated from that. I will try to take that same coil that I have been talking about and use your suggestion to see how close the results are. However, I am preparing for a 6 state Harley road trip over the Easter holidays and will not be back until Monday. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223476 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 20:43:36 -0500 Message-ID: <17929-443C5B48-959@storefull-3255.bay.webtv.net> References: <1144799035.064183.9530@v46g2000cwv.googlegroups.com> Tom, W8JI wrote: "The directional coupler in a Bird meter samples the across vector (voltage) from a capacitive divider and adds it to a sample voltage of the through vector (current) from a current transformer in a predetermined ratio. That`s close. In the cartridges is a loop terminated in a diode. Capacitive coupling of the loop to the center conductor of the precision ccoax supplies the voltage sample. Inductive coupling of the loop supplies the current sample. I`ve described operation several times here and once in this thread, so I won`t repeat it. SWR is easy to get from the forward and reflected indications of the wattmeter. VSWR = 1 + sq.rt. (ref. PWR / for. PWR) Divided by 1 - sq.rt. (ref. PWR / for. PWR) Bird supplies a family of VSWR lines on a graph of forward power vs. reflected power for those who would avoid the calculation. They can also supply a slide-rule to do rhe same. Best regards, Richard Harrison, KB5WZI Article: 223477 of rec.radio.amateur.antenna From: "CW" References: <-tidnctwIpeFdKjZnZ2dnUVZ8s2dnZ2d@bt.com> Subject: Re: Source cod of program LINE_ZIN Message-ID: Date: Wed, 12 Apr 2006 01:59:43 GMT Source cod? There's fish involved? :) "Reg Edwards" wrote in message news:-tidnctwIpeFdKjZnZ2dnUVZ8s2dnZ2d@bt.com... > To satisfy the curiosity of people who may be interested in such > things, I have made the source code of program LINE_ZIN available from > my website. Look in the index for "Download Source Code from Here". > > You can make what use you like of the information contained therein > but I don't have the time to provide any assistance or tutorial. And > don't make any reference to Yours Truly. > > It's all free to USA citizens. > > Download text file LINE_ZIN.pas from website below. > ---- > ........................................................... > Regards from Reg, G4FGQ > For Free Radio Design Software go to > http://www.btinternet.com/~g4fgq.regp > ........................................................... > > Article: 223478 of rec.radio.amateur.antenna From: "Spock" Subject: HF discone ????????????? Date: Wed, 12 Apr 2006 12:04:06 +0930 Message-ID: <443c671f$0$10677$afc38c87@news.optusnet.com.au> Hello Everyone I saw somewhere that the us navy used on some of it's ships hf discone antennas. Were they any good? are they practical? what are the pros and cons? are they used commercially? Than you. --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 0615-1, 11/04/2006 Tested on: 12/04/2006 12:04:06 PM avast! - copyright (c) 1988-2005 ALWIL Software. http://www.avast.com Article: 223479 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 20:06:22 -0700 Message-ID: <123orli9a52nr5e@corp.supernews.com> References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> Mike Coslo wrote: > Yuri Blanarovich wrote: >> Check my article that describes the controversy, shows some proof of >> reality and then efforts of the "gurus" to deny it and "reason" why >> it can't be so. http://www.k3bu.us/loadingcoils.htm The problem is >> that back in 1953 in QST article there was erroneous >> conclusion/statement made, which propagated through the books, until >> W9UCW measured the current across the loading coils and found that >> there is significant drop from one end to the other, and the rest is >> (ongoing) history > > Hmm, certainly it would seem to make sense that: > >> The current in a typical loading coil in the shortened antennas drops >> across the coil roughly corresponding to the segment of the radiator >> it replaces. > > Quote from your page. > > I would not expect anything else. If the loading coil is making the > antenna act like a physically longer antenna, other "qualities" of that > simulation are likely to be similar. > > Is there a reason why the coil would *not* do this? Yes, many, and they've been discussed here at length. That this concept is wrong can and has been shown by theory, modeling, and measurement. I made and posted measurements on this newsgroup in November 2003 which demonstrated clearly that the presumption is false. The loading coil isn't making the antenna act like a physically longer antenna. In the extreme case of a physically short inductor at the feedpoint, it's simply modifying the feedpoint impedance and has no effect whatever on the antenna's radiation. As the inductor gets longer, it does become some part of the antenna, but adding an inductor which resonates, say, a 45 degree physical radiator doesn't make the antenna act like a 90 degree physical radiator. Roy Lewallen, W7EL Article: 223480 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Current across the antenna loading coil - from scratch Date: Tue, 11 Apr 2006 22:24:50 -0500 Message-ID: <123osonj6puofe0@corp.supernews.com> References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> <1144784891.274341.118940@z34g2000cwc.googlegroups.com> <1144793465.690849.152810@g10g2000cwb.googlegroups.com> <2vlo325r080645tk7m23rjbv0tunkm4knb@4ax.com> Wes Stewart wrote: > > Responding to no one in particular. > > This is starting to make me miss the shorter Fractenna threads. > > Phil, comeonback good buddy. They certainly made more sense. Dave N Article: 223481 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <443c671f$0$10677$afc38c87@news.optusnet.com.au> Subject: Re: HF discone ????????????? Message-ID: Date: Tue, 11 Apr 2006 21:42:26 -0700 "Spock" wrote in message news:443c671f$0$10677$afc38c87@news.optusnet.com.au... > Hello Everyone > I saw somewhere that the us navy used on some of it's ships hf discone > antennas. Were they any good? are they practical? what are the pros and > cons? are they used commercially? > > Than you. Yes, They were fine. Worked well, practical, but heavy and took up a lot of "real estate" topside. Useful over the freq range 10-30 in most cases. There may be one or two left in the active Navy, but they have mostly been replaced by twin whips. I think USS Belleau Wood (decommissioned October, 2005) still had the discone/cage combination antenna at that time. The USS Missouri Memorial has one. You need a sturdy center mast to support the cone section which is made of about 25 wires. It's about 25 ft tall. The disk is insulated and sits atop the mast. The advantage is that it's broadbanded. Good VSWR across the band. Not much use for hams, since we just have those little slices of the band. One vertical omni antenna has coverage just like all the other vertical omnis. So, you might not want to bother, except for the fun of doing it and seeing that it works. I agree, that's reason enough for some, but it will be a lot of effort. ARRL Antenna Book covers it nicely, too, I see. John, KD6VKW Combat Systems Tech, Southwest RMC, San Diego Naval Station Article: 223482 of rec.radio.amateur.antenna From: Mike M. Subject: Comet CA-2x4SR Message-ID: Date: Wed, 12 Apr 2006 08:53:21 GMT I have a Comet CA-2x4SR 2m/70cm mobile antenna on a trunk lid mount. Comet tells me this is a "ground independent" antenna, so I've been thinking about adding a short mast to get it above the cars roof line. Will I gain or lose anything by raising the antenna above the ground plane? I'm hoping raising it would give a more circular pattern by getting it above the roof line and above the 150/450 MHz scanner antenna mounted on the other side of the trunk. Article: 223483 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Message-ID: Date: Wed, 12 Apr 2006 12:50:01 GMT Roy Lewallen wrote: > Yes, many, and they've been discussed here at length. That this concept > is wrong can and has been shown by theory, modeling, and measurement. I > made and posted measurements on this newsgroup in November 2003 which > demonstrated clearly that the presumption is false. By now, even you know that standing wave current phase is fixed and unchanging and that those delay measurements of yours are invalid whether made on a wire or on a coil. > The loading coil isn't making the antenna act like a physically longer > antenna. Of course not! The loading coil is making the antenna act like an electrically longer antenna by adding a phase shift through the coil. The electrical lengthening is what resonates the antenna feedpoint to a pure resistance. > In the extreme case of a physically short inductor at the > feedpoint, it's simply modifying the feedpoint impedance and has no > effect whatever on the antenna's radiation. Nobody has ever said it affected the antenna's radiation so that has been and is still just a straw man. > As the inductor gets longer, > it does become some part of the antenna, but adding an inductor which > resonates, say, a 45 degree physical radiator doesn't make the antenna > act like a 90 degree physical radiator. Of course not and nobody has ever said it does. It increases the electrical length and brings the forward and reflected waves into phase with each other. That's why the the feedpoint impedance is resistive. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223484 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144799035.064183.9530@v46g2000cwv.googlegroups.com> <17929-443C5B48-959@storefull-3255.bay.webtv.net> Message-ID: Date: Wed, 12 Apr 2006 13:02:22 GMT Ian White GM3SEK wrote: > The disagreement is entirely about the interpretation - in other words, > it's about the theory about standing and travelling waves. Richard > habitually misses out this step, which makes it look as if the Bird > wattmeter "proves" the physical existence of forward and reverse > travelling waves of power. Those are traveling waves of *EM energy* where the power is indicated at a point as the energy flows through that point. Assuming Z0=50 ohms, the Bird indicates the number of joules per second flowing toward the load when the slug is in the forward position. Turning the slug around causes the Bird to indicate the number of joules per second flowing toward the source. The only way to have standing waves of EM energy in a transmission line is to have two EM waves flowing in opposite directions. I have asked you before to explain how standing waves develop without the existence of a forward traveling wave and a rearward traveling wave. Your silence on that subject has been conspicuous by its absence. Do standing waves appear by magic? > It doesn't. Everything that you see printed on the Bird's meter scale, > and in the Bird literature, represents that company's particular > interpretation of theory about waves on transmission lines. The details > of that theory are *not* agreed within this newsgroup, which means that > - to some people - the two halves of Richard's claim do not join up. Are you asserting that Bird is engaging in false advertising? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223485 of rec.radio.amateur.antenna From: chuck Subject: Re: Current across the antenna loading coil - from scratch References: <1144799035.064183.9530@v46g2000cwv.googlegroups.com> <17929-443C5B48-959@storefull-3255.bay.webtv.net> Message-ID: Date: Wed, 12 Apr 2006 13:27:03 GMT Ian White GM3SEK wrote: [SNIP] > > The disagreement is entirely about the interpretation - in other words, > it's about the theory about standing and travelling waves. Richard > habitually misses out this step, which makes it look as if the Bird > wattmeter "proves" the physical existence of forward and reverse > travelling waves of power. > > It doesn't. Everything that you see printed on the Bird's meter scale, > and in the Bird literature, represents that company's particular > interpretation of theory about waves on transmission lines. The details > of that theory are *not* agreed within this newsgroup, which means that > - to some people - the two halves of Richard's claim do not join up. > Ian, I've not detected this particular disagreement about waves on transmission lines in the group. I would be most grateful to see a brief statement of where and how Bird's interpretation of theory is found infirm. 73, Chuck NT3G Article: 223486 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144830734.559464.67410@u72g2000cwu.googlegroups.com> Message-ID: Date: Wed, 12 Apr 2006 13:33:13 GMT w8ji@akorn.net wrote: > The loading coil doesn't "replace" missing electrical degrees, it > primarily corrects power factor by compensating reactance. If correcting the power factor didn't cause a phase shift, the power factor wouldn't change but we know it does. That phase shift is exactly what we are talking about. The coil shifts the phase of both the forward wave and reflected wave thus furnishing some much needed electrical degrees in order to resonate the antenna by bringing the phasor sum of the forward and reflected voltages into phase with the phasor sum of the forward and reflected currents. Any power engineering textbook will tell you what happens to the phase when the power factor is corrected. Hint: If the phase stayed the same, as you assert, nothing would change. But we know that correcting the power factor changes the phase. That's exactly what correcting the power factor is all about. > The truth is the loading inductor almost never has the same phase shift > in current as the missing antenna area it replaces, and it almost never > has the same "current drop". The inductor does indeed contribute a phase shift that is not zero. In a one wavelength system, the coil can just as easily contribute a current RISE as a current DROP. That fact alone is reason to drop the flawed model. Current cannot be created in a coil by sucking it out of earth ground which is what your theory have us believe. But of course, you have refused to discuss the subject. > I can have an antenna of given dimensions with a loading coil at one > fixed spot. The difference in current flowing into one end and out the > other can go all over the place, depending only on the coil's physical > design wity the antenna resonant on the same frequency. This happens > ONLY by changing the coil. Of course, but that is beside the point. Every real world inductor does contribute its own unique phase shift and its own unique current change, rise, fall, or equal at current nodes and antinodes. You have absolutely refused to discuss that current rise. One wonders why. > If I had a coil that was compact and not against the groundplane with > low stray capacitance compared to the antenna area above the coil, > current difference between each terminal or through the coil could be > immeasurable with reasonably good instrumentation. Phase shift in > current could also be nearly zero. None of this would be anywhere near > the area the coil replaces. Resorting to a specially designed coil completely different from anything used in the real world has been your specialty. If your theory only works for only one special case and is not valid for the general case, it's time to junk that theory. After failing a dozen times to achieve equal current at both ends of numerous coils, you finally declared victory using a small toroidal coil. Uhhhh Tom, one out of twelve doesn't prove much. I have shown you how to achieve equal current with any coil. It just depends upon where the coil is placed in the standing wave environment. > A few people have violated the rules of charge conservation, charge > movement, and misapplied the concept of standing waves, but the single > largest error is standing behind the myth or misconception that that > loading coil somehow acts like the "missing area of antenna". The coil's function is to bring the forward and reflected waves into phase so the feedpoint impedance will be purely resistive. It cannot do that if it has no effect on phase. Your theory is full of holes. The coil affects the electrical length of the antenna, not the physical length. Nobody has ever said it replaces the missing physical length of the antenna. Your implication is that same tired old straw man riding that same old dead horse. Please stop trying to twist what we are saying and fix the twist in your own misconceptions. For instance, how does your theory handle a current rise through a coil as illustrated at: http://www.qsl.net/w5dxp/test316.GIF in the right hand part of the graphic. Why do you refuse to discuss this current RISE? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223487 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> <1144787795.664748.325710@z34g2000cwc.googlegroups.com> <1144841185.770853.143110@i40g2000cwc.googlegroups.com> Message-ID: Date: Wed, 12 Apr 2006 13:39:20 GMT K7ITM wrote: > In your two messages included above by reference, you complained that I > had in the other two included messages put things you had written, but > that I did not properly attribute them to you. I don't know whether to > be offended, feel sorry for you, or laugh. In each of my two messages, > immediately following my signature, is a line that begins, "Cecil > wrote..." I trust it's not too difficult for most folk to understand, > but I'll explain it for you. That line means that YOU wrote the stuff > that follows that line, not me. In general, I would absolutely NOT > want anyone to think I'd written anything you wrote! Guess I'm > inclined to feel a bit of the second, and do some of the third. You are doing the "Cecil wrote" in the wrong way and falsifying attributions in the process. If you want to be known as the netnews guy who falsifies attributions, that is your business. What I am officially asking you to do is to cease and desist falsifying the attributions associated with my postings. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223488 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Wed, 12 Apr 2006 10:08:15 -0400 "Roy Lewallen" wrote in message news:123orli9a52nr5e@corp.supernews.com... > Mike Coslo wrote: >> Yuri Blanarovich wrote: >>> Check my article that describes the controversy, shows some proof of >>> reality and then efforts of the "gurus" to deny it and "reason" why >>> it can't be so. http://www.k3bu.us/loadingcoils.htm The problem is >>> that back in 1953 in QST article there was erroneous >>> conclusion/statement made, which propagated through the books, until >>> W9UCW measured the current across the loading coils and found that >>> there is significant drop from one end to the other, and the rest is >>> (ongoing) history >> >> Hmm, certainly it would seem to make sense that: >> >>> The current in a typical loading coil in the shortened antennas drops >>> across the coil roughly corresponding to the segment of the radiator >>> it replaces. >> >> Quote from your page. >> >> I would not expect anything else. If the loading coil is making the >> antenna act like a physically longer antenna, other "qualities" of that >> simulation are likely to be similar. >> >> Is there a reason why the coil would *not* do this? > > Yes, many, and they've been discussed here at length. That this concept is > wrong can and has been shown by theory, modeling, and measurement. I made > and posted measurements on this newsgroup in November 2003 which > demonstrated clearly that the presumption is false. > > The loading coil isn't making the antenna act like a physically longer > antenna. In the extreme case of a physically short inductor at the > feedpoint, it's simply modifying the feedpoint impedance and has no effect > whatever on the antenna's radiation. As the inductor gets longer, it does > become some part of the antenna, but adding an inductor which resonates, > say, a 45 degree physical radiator doesn't make the antenna act like a 90 > degree physical radiator. > > Roy Lewallen, W7EL Oooops, carefull here. As far as I know, nobody has claimed that inserted loading coil replaces the "missing" degrees of the radiator in terms of providing magical properties that would look like that "replaced" portion of the antenna, or make the antenna act like 90 degree full size physical radiator. What we are saying that the loading coil appears to replace "missing" electrical degrees of the radiator in order to make it resonant, that is back to 90 electrical degrees (has to be in order to resonant), which rest of the existing "straight" radiator forces it to do (+/-). Radiation properties and efficiency of the loaded antenna is proportional to the area under the current curve. It is obvious to anyone comparing the area under the current curve of full size quarter wave radiator vs. loaded radiator that there is huge difference in area under the curve and performance, efficiency, which is known and been verified by numerous measurements. HOW the current curve is modified by different loadings and position along the radiator is important in knowing how the current distribution curve along the radiator is modified. The whole controversy is that "gurus" claim current doesn't drop across the coil, while we say that it does, therefore making the area under current curve above the coil smaller and effciency of loaded antenna worse than they believe and insist on. Again, when applied in modeling programs, wrong assumption will produce erroneous results, which will be magnified in multielement antenna designs. So the "gurus" basically ignore behavior of coil in the standing wave environment along the loaded radiator, where the current drops from max at base to zero at the tip, but coil would magicaly resist that, because, bla, bla, bla.... (see their "reasons") So while everyone knows (?) that standing wave current drops acros (along) the wire (all the antenna books show that), but it is "impossible" to drop along the coiled wire (real inductance - coil, loading stub). Reality and measurments prove that, but according to them "it can't be so". I am already gathering necessary hardware to do more experiments, measurements to show what is really happening, and will prepare articles how to model and apply it to antenna design. I would challenge the "unbelievers" to join me and repeat the tests, to see wasaaaap. 73 Yuri, K3BU Article: 223489 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Message-ID: Date: Wed, 12 Apr 2006 15:25:44 GMT Yuri Blanarovich wrote: > What we are saying that the loading coil appears to replace "missing" > electrical degrees of the radiator in order to make it resonant, ... W8JI says we are correcting the power factor. Every EE knows that correcting the power factor involves shifting the phase, i.e. the coil cannot correct the power factor without providing a phase shift. > The whole controversy is that "gurus" claim current doesn't drop across the > coil, while we say that it does, ... That context is specifically inductively loaded mobile antennas where the current decreases from source to tip of the antenna, true for all electrical 1/4WL monopoles. For other antennas, the current may DROP, the current may RISE, or the current may STAY THE SAME magnitude depending upon where the coil is installed in the standing wave system. In particular, none of the "gurus" has even attempted to explain the RISE IN CURRENT through the coil in the right hand system at: http://www.qsl.net/w5dxp/test316.GIF There have been about 10 examples proving the "gurus" wrong and they simply chose to ignore those examples. They complain that those examples are biased toward technical correctness. I say, YES, THEY ARE. AREN'T THEY SUPPOSED TO BE TECHNICALLY CORRECT? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223490 of rec.radio.amateur.antenna From: "amdx" Subject: Improving FM in building Date: Wed, 12 Apr 2006 10:28:23 -0500 Message-ID: <2bf27$443d1c89$45011502$10556@KNOLOGY.NET> The health club I belong to has poor FM reception inside the building. I'm trying to get them to improve it. The thought I have is to install an outside omni antenna and connect it to an inside identical antenna hanging down from the ceiling. Is this a workable idea? Does anyone have info to help make the improvements? Thanks Mike PS---This is for all the personal FM radios worn by the exercisers. Article: 223491 of rec.radio.amateur.antenna From: chuck Subject: Re: Current across the antenna loading coil - from scratch References: <1144799035.064183.9530@v46g2000cwv.googlegroups.com> <17929-443C5B48-959@storefull-3255.bay.webtv.net> Message-ID: Date: Wed, 12 Apr 2006 16:11:20 GMT Thank you, Ian, for the quick and thorough reply! I look forward to reading both papers. 73, Chuck NT3G Article: 223492 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Wed, 12 Apr 2006 11:08:50 -0500 Message-ID: <3988-443D2612-839@storefull-3256.bay.webtv.net> References: Ian White, GM3SEK wrote: "---it`s about the theory about standing waves and traveling waves." Bird is congruent with Terman. Both have been around for a long time and the theory works. Reverse engineer the Bird. The critical step is adjusting the two samples for equality so that the 180-degree phase shift reflection causes produces cancellation in one direction of pickup so that the samples from the other direction can be measured. Best regards, Richard Harrison, KB5WZI Article: 223493 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144799035.064183.9530@v46g2000cwv.googlegroups.com> <17929-443C5B48-959@storefull-3255.bay.webtv.net> Message-ID: Date: Wed, 12 Apr 2006 16:49:56 GMT Ian White GM3SEK wrote: > Now what happens if the load is not exactly 50 ohms? If the feedline is 50 ohms, what happens is reflected energy that is easily visible using a TDR, time domain reflectometer. > One is that if the meter scale says "power", then there genuinely are > forward and reflected traveling waves of power on the line. In the "93 - > 23 = 70W" example, the belief is that there genuinely is a power flow of > 93W towards the load, only 70W of which is accepted and 23W is returned. One correction. The Bird wattmeter is installed at a point on the transmission line and it measures the power at that point. What is traveling is the energy. Power is the number of joules per second passing a fixed point. "Power flow" is somewhat of a misnomer. > The other school of thought is that that's not true. The meter may > *read* more "forward power" than is actually being delivered to the > load, but that is a false indication because the instrument is not being > used in the situation for which the power scale was calibrated. It certainly is being used in the situation for which it was calibrated if the Z0 of the transmission line is 50 ohms. > On the other hand, we have yet to see an explanation in equivalent > physical detail that is based entirely and exclusively on the viewpoint > of travelling waves of power ... Please give up on your misconception. Those are traveling waves of *ENERGY*. Power is what is measured when traveling energy passes a fixed point. Perhaps that is your whole point of confusion. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223494 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Current across the antenna loading coil - from scratch Date: Wed, 12 Apr 2006 11:55:10 -0500 Message-ID: <25827-443D30EE-864@storefull-3257.bay.webtv.net> References: Cecil, W5DXP wrote: "Any power engineering handbook will tell you what happens to the phase when the power factor is corrected." Most industrial loads have a lagging power factor. They represent an inductive reactance in addition to their resistive loads. Extra energy must be generated and transmitted just to charge this inductance which does no work but demands current. Extra loss comes from this reactive load. This is eliminated by tuning the inductance out with a capacitive reactance at the load. This is often an overexcited synchronous motor. When the motor has no mechanical load it is often called a "synchronous capacitor". An antenna needs zero reactance too if it is to accept maximum energy and not make standing waves. Reactance impedes energy to the antenna. Reactive current also increases loss in the transmission line as it does in the case of the power utility frequency. So j0 is a goal in many instances. Best regards, Richard Harrison, KB5WZI Article: 223495 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <25827-443D30EE-864@storefull-3257.bay.webtv.net> Message-ID: <9Da%f.15280$tN3.4201@newssvr27.news.prodigy.net> Date: Wed, 12 Apr 2006 17:17:57 GMT Richard Harrison wrote: > Cecil, W5DXP wrote: > "Any power engineering handbook will tell you what happens to the phase > when the power factor is corrected." > > Most industrial loads have a lagging power factor. They represent an > inductive reactance in addition to their resistive loads. Extra energy > must be generated and transmitted just to charge this inductance which > does no work but demands current. Extra loss comes from this reactive > load. This is eliminated by tuning the inductance out with a capacitive > reactance at the load. Yet W8JI would have us believe that power factor correcting capacitor functions faster than the speed of light, making an instantaneous phase correction. Sorry, the real world doesn't work that way. The bottom line is that we cannot shift phase without delaying something, either voltage or current. Contrary to the presuppositions of the lumped-circuit model, neither voltage nor current can travel faster than the speed of light. That means that any phase shifting of the relative phase angle difference down to zero results in a delay. I have seen it explained as "apparently" traveling faster than light. That's just one more patch on an already flawed mode. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223496 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Message-ID: Date: Wed, 12 Apr 2006 17:25:58 GMT John Popelish wrote: > A series inductor (a non real, ideal one) with absolutely no phase shift > or magnitude change in the current from one end to the other, still > produces a phase shift of input voltage to output voltage, ... If the voltage is leading the current, and the current experiences no phase shift through the coil, doesn't that imply that the voltage must travel faster than light and indeed jump forward in time to catch up with the phase of the current? What does it mean to the E-fields and H-fields to say the voltage is leading the current? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223497 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> <1144787795.664748.325710@z34g2000cwc.googlegroups.com> <1144841185.770853.143110@i40g2000cwc.googlegroups.com> <1144862643.496243.251990@t31g2000cwb.googlegroups.com> Message-ID: Date: Wed, 12 Apr 2006 17:43:55 GMT K7ITM wrote: > Yes, well, thank you _very_ much indeed, Cecil, for this further > insight into the workings of your mind. If you consider a request for you to honor the netnews guidelines for attributions a problem, then it's your problem, not mine. No ethical person would attribute one person's postings to someone else. If you don't like that attitude, I suggest you cease and desist from violating the netnews guidelines for attributions. I'm going to point it out every time you attribute a posting >from someone else to me or when you attribute one of my postings to someone else. When trimming one line attributes the posting to a completely different person, that is a clear violation. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223498 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> <1144787795.664748.325710@z34g2000cwc.googlegroups.com> <1144841185.770853.143110@i40g2000cwc.googlegroups.com> <2veq3214birv21c9r8iol2kq20ha4jsi4r@4ax.com> Message-ID: Date: Wed, 12 Apr 2006 17:49:31 GMT Richard Clark wrote: > Cecil Moore >What I am officially asking you to do is to cease and desist > > Is that you Herr Doktor? That's a legal term under Texas law. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223499 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Wed, 12 Apr 2006 11:43:03 -0700 Message-ID: <123qihrf94k80e8@corp.supernews.com> References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Yuri Blanarovich wrote: > > Oooops, carefull here. > As far as I know, nobody has claimed that inserted loading coil replaces the > "missing" degrees of the radiator in terms of providing magical properties > that would look like that "replaced" portion of the antenna, or make the > antenna act like 90 degree full size physical radiator. Agreed, it's not quite stated as such. Here are some statements which were made: From your web page http://www.k3bu.us/loadingcoils.htm, in bold type: "In summary: The current in a typical loading coil in the shortened antennas drops across the coil roughly corresponding to the segment of the radiator it replaces." By Cecil, on March 5, on this newsgroup: "A loading coil thread is climaxing over on qrz.com. I have used EZNEC to generate a graphic which shows a 3/4WL vertical and a similar 1/2WL vertical with a ~1/4WL loading coil. The loading coil is a wire helical coil containing (surprise) roughly 1/4WL of wire. The coil does a good (not perfect) job of replacing 1/4WL of wire. Many things can be gathered >from observation of the current reported by EZNEC for the two antennas. The coil occupies roughly the same number of degrees of the antenna as the wire it replaces. The current at the top and bottom of the coil is roughly the same as the current at the two ends of the wire it replaces. Is the coil an exact replacement? Of course not." > What we are saying that the loading coil appears to replace "missing" > electrical degrees of the radiator in order to make it resonant, that is > back to 90 electrical degrees (has to be in order to resonant), which rest > of the existing "straight" radiator forces it to do (+/-). It's getting muddier and muddier just what you mean by "replace". Nobody has questioned that a loading coil makes the antenna resonant; that's its purpose. But that's simply an impedance transformation property which can be accomplished well away from the antenna by many different methods. > Radiation > properties and efficiency of the loaded antenna is proportional to the area > under the current curve. It is obvious to anyone comparing the area under > the current curve of full size quarter wave radiator vs. loaded radiator > that there is huge difference in area under the curve and performance, > efficiency, which is known and been verified by numerous measurements. > HOW the current curve is modified by different loadings and position along > the radiator is important in knowing how the current distribution curve > along the radiator is modified. I agree with all this. I'm glad you've clarified this for the benefit of posters like the one to whom my recent posting was directed. > The whole controversy is that "gurus" claim current doesn't drop across the > coil, while we say that it does, therefore making the area under current > curve above the coil smaller and effciency of loaded antenna worse than they > believe and insist on. I don't think you'll have any trouble winning your arguments against your imaginary "gurus", whomever and whatever they might be. Over two years ago I made careful measurements which showed a current difference between the top and bottom of a loading coil. Cecil posted an EZNEC model on his web site showing a substantial difference. I've commented on it several times, explaining the reason for the difference, and modifying the model to illustrate the explanation. The controversy is in the explanation of the difference. It simply doesn't require Cecil's theories. I've never been able to tell exactly what your theory is, if you indeed have one. > Again, when applied in modeling programs, wrong assumption will produce > erroneous results, which will be magnified in multielement antenna designs. > So the "gurus" basically ignore behavior of coil in the standing wave > environment along the loaded radiator, where the current drops from max at > base to zero at the tip, but coil would magicaly resist that, because, bla, > bla, bla.... (see their "reasons") Would you name these "gurus" so we can read their postings and see what you're talking about? > So while everyone knows (?) that standing wave current drops acros (along) > the wire (all the antenna books show that), but it is "impossible" to drop > along the coiled wire (real inductance - coil, loading stub). Reality and > measurments prove that, but according to them "it can't be so". > > I am already gathering necessary hardware to do more experiments, > measurements to show what is really happening, and will prepare articles how > to model and apply it to antenna design. > I would challenge the "unbelievers" to join me and repeat the tests, to see > wasaaaap. You'll be surprised when everyone agrees that there's a current difference between the top and bottom of the coil. Unless your "gurus" show up, whomever they are. I've already made a test and posted the results, over a year ago. When it failed to show a current difference anywhere near the number of degrees it "replaced", your complaint was that I was using an inductor which was too small physically. So obviously your theory works only on certain size inductors. Once you or Cecil has the theory fully worked out, it should be able to not only tell us what the current difference between top and bottom should be, but also how physically large an inductor must be before the theory works. And why it doesn't work for physically small inductors. Those of us stuck with old fashioned conventional theory can explain the drop for small as well as large coils, so you folks have a bit of catching up to do. I think a lot of the experimental work can be done by modeling. I'd be interested in hearing of any cases where measured results differ significantly from EZNEC results. Incidentally, your web page is a bit outdated in that respect, apparently being written before EZNEC v. 4.0 was available with its automated helix creation feature. Roy Lewallen, W7EL Article: 223500 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Current across the antenna loading coil - from scratch Date: Wed, 12 Apr 2006 12:15:24 -0700 Message-ID: References: <1144787795.664748.325710@z34g2000cwc.googlegroups.com> <1144841185.770853.143110@i40g2000cwc.googlegroups.com> <2veq3214birv21c9r8iol2kq20ha4jsi4r@4ax.com> <5nfq321v4ue0h1hlgcobbsj6g5b68hhmn0@4ax.com> On Wed, 12 Apr 2006 19:02:56 GMT, Cecil Moore wrote: >Richard Clark wrote: > >> Cecil Moore wrote: >>>That's a legal term under Texas law. >> >> Oh, must be Phil then, Herr Doktor never explains anything. > >I thought the explanation was obvious. If I am going to >get sued because of false attributions, I need a paper >trail and proof that I objected to those false attributions. Paper trail? Phil, push over those stacks of "research" and fire up the Xerox! Article: 223501 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> <%pc%f.69283$dW3.66938@newssvr21.news.prodigy.com> Message-ID: Date: Wed, 12 Apr 2006 19:58:16 GMT Cecil Moore wrote: > > > Roy, maybe you need to learn the definition of "roughly". > It is certainly not "exactly" as you are clutching at straws > to imply. Why you need to change the definitions of words > is obvious from your flawed arguments. Exactly what is > it about "roughly" that you don't understand? Cecil, Is 10 degrees of phase shift "roughly" equal to 75 degrees of phase shift? I don't think anyone is trying to nit-pick the numbers to a precision of several significant figures. A multiple of greater than 7 would seem to be just a bit outside the scope of "roughly". 73, Gene W4SZ Article: 223502 of rec.radio.amateur.antenna From: Ed Bailen Subject: Re: Grounding Bar Length For Receiving Only Antenna Date: Wed, 12 Apr 2006 15:03:06 -0500 Message-ID: References: <1144784784.419166.221570@j33g2000cwa.googlegroups.com> I don't know that I buy your statement that ground losses aren't extremely important for receiving applications. Antenna systems are bi-directional. If you lose xdB of transmitted sigal due to ground losses, then you are also going to lose xdB of received signal due to ground losses. A more important issue is that ground losses are very important when receiving a lightning strike. It may be effective to bury several runs of bare #6 copper in trenches radiating from your "ground point". The QTH here is located on a solid rock slab. All grounding is through buried #6 wires and a few ground rods driven laterally between the rock layers up by the tower base. Regards, Ed On 11 Apr 2006 12:46:24 -0700, "n3ox.dan@gmail.com" wrote: >Hi Bob, > >Ground losses aren't extremely important for receiving applications. A >few extra feet of depth of ground rod isn't going to make any >difference, because the RF doesn't flow 8 feet down, or 5 feet down, >but more flows on the surface of the ground and/or some inches down >(depending on your ground conductivity profile) > >As such, you could try a 4 or 5 foot ground rod. > >If you want a no-pounding solution instead, lay down a few radial >wires. The length and number aren't critical. Try four or eight wires >each 1/8 wavelength long at the lowest frequency of interest. > >If the noise in your receiver doesn't increase when you plug the >antenna into the RX , then you may want a better ground system. If the >noise DOES increase, then your noise floor is that of the >natural/artificial noise that your antenna is picking up, and more raw >signal from the antenna won't help anything. (Though moving the >antenna around might). > >73, >Dan >N3OX >www.n3ox.net Article: 223503 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Wed, 12 Apr 2006 20:45:36 GMT Cecil, I will retain the entire message below, so that I am not accused of misattribution. Where did you get this idea that the velocity factor is constant? Specifically, why is the velocity factor of a resonant coil the same as the velocity factor of a significantly shorter coil? It is pretty well accepted that the inductance of coils does not scale linearly with the length of the coil. Therefore any arguments about based on direct calculation of Vf from L and C would seem to fail to support your model. I can think of two possibilities. The first is that you treat this entire problem as a transmission line. Most people would accept that the velocity factor for 200 feet of RG8 is indeed the same as the velocity factor for 100 feet of the same cable. However, the velocity factor appears to be the crux of your latest argument about the behavior of a loading coil. It is not exactly acceptable technique to include the desired answer as part of the proof. The other possibility is that you are taking the lead from one of the Corum papers. In particular, I am referring to the paper labeled: "TELSIKS 2001, University of Nis, Yugoslavia (September 19-21, 2001) and MICROWAVE REVIEW" If so, I suggest you go back and reread what was written. He specifically says (page 4, left column) that the equations for velocity factor that show Vf as a function of diameter, spacing, and wavelength apply only at resonance. The exact words are: " . . . an approximation for M has been determined by Kandoian and Sichak which is appropriate **for quarter-wave resonance** and is valid for helices . . ." The emphasis on quarter-wave resonance was in the original; I did not change a thing. The remainder of the paper clearly indicates that he is talking about coils near or at resonance. There is no extension of the Vf equations to short non-resonant coils. Indeed, he comments several times that his model smoothly joins with the lumped circuit model for smaller coils. That would require a non-constant Vf. You attempt at decomposition of a resonant coil into smaller subcomponents simply fails. This is not an "ignorant diversion". If you have a third method of supporting your claim of constant Vf, let's hear it. 73, Gene W4SZ Cecil Moore wrote: > Gene Fuller wrote: > >> Cecil Moore wrote: >> >>> Gene Fuller wrote: >>> >>>> So you think adding turns to a coil is a nice linear process that >>>> allows you to then subdivide the resonance effects according the >>>> number of turns in each subsection? >>> >>> >>> That appears to me to be the most valid measurement that we >>> can make of the delay through a coil. If you have a better >>> way, please present it. >> >> >> C'mon, you know as well as anybody that inductance of a coil tends to >> increase as n-squared. Yes, there are all kinds of special cases and >> correction factors. > > > Increasing the length of a coil or transmission line doesn't > change its velocity factor at a fixed frequency. > >> Adding turns and then pretending everything is nice and linear, >> thereby allowing decomposition into subcomponents, is just plain silly. > > > Velocity factor is *nice* and linear, i.e. it is constant. > > Please stop these diversions. I'm sure you are not that ignorant. Article: 223504 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Current across the antenna loading coil - from scratch References: <1144787795.664748.325710@z34g2000cwc.googlegroups.com> <1144841185.770853.143110@i40g2000cwc.googlegroups.com> <2veq3214birv21c9r8iol2kq20ha4jsi4r@4ax.com> <5nfq321v4ue0h1hlgcobbsj6g5b68hhmn0@4ax.com> Message-ID: <8Pd%f.67947$Jd.27312@newssvr25.news.prodigy.net> Date: Wed, 12 Apr 2006 20:55:32 GMT Cecil Moore wrote: > Richard Clark wrote: > >> Paper trail? Phil, push over those stacks of "research" and fire up >> the Xerox! > > > I am indeed printing out the postings just in case the false > attributions result in a lawsuit against me. I can't afford > not to be careful. Cecil, no one but a madman would ever sue you for anything. Your presence alone would wreck any legal proceeding even in a state as idiosyncratic as Texas. 73, Tom Donaly, KA6RUH Article: 223505 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> <%pc%f.69283$dW3.66938@newssvr21.news.prodigy.com> Message-ID: <6Rd%f.6028$1q4.4181@bgtnsc05-news.ops.worldnet.att.net> Date: Wed, 12 Apr 2006 20:57:38 GMT Cecil Moore wrote: > Gene Fuller wrote: > >> Is 10 degrees of phase shift "roughly" equal to 75 degrees of phase >> shift? > > > Of course not. The 10 degrees of phase shift has already been > proven to be wrong because of reflections within the coil. > Why do you insist on bringing up old invalid data? > > Please note that *nobody* is alleging that the phase shift > through a 75m bugcatcher coil is 75 degrees. That is just > another one of your straw men. > > Now why don't you become a rational, ethical person and > suggest a valid way of measuring the phase shift through > a coil? Can you improve on my suggestion of yesterday? Cecil, You spent a lot of time developing the "10 degree" model for the bugcatcher coil. When and how did it get proven wrong? The only thing I can recall is that you said it did not make sense technically, and therefore it must be wrong. Recently you launched into this business about adding turns to make the coil resonant. As I just explained, I believe that approach is total nonsense. You keep referring everyone to the now famous gif image on your web page. The question becomes why is EZNEC correct in supporting your position at some times and incorrect when it does not support your position at other times? 73, Gene W4SZ Article: 223506 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144799035.064183.9530@v46g2000cwv.googlegroups.com> <17929-443C5B48-959@storefull-3255.bay.webtv.net> Message-ID: Date: Wed, 12 Apr 2006 21:00:21 GMT Ian White GM3SEK wrote: > Cecil, in all sincerity, have a good trip and please drive safely. I'd > have been much safer on the roads last weekend if I hadn't been thinking > about this stuff as well. Sincerely, Ian, how do you explain one amp on the source side of a coil and two amps on the whip side of a coil? Nothing in your response even came close to answering that question. If you are dedicated to technical correctness, your evasion of this technically simple question is perplexing. How is it possible to have one amp "flowing into" the bottom of a coil and two amps "flowing out" of the top of the coil? If you really believe that one amp is flowing from the earth ground to the coil through displacement current, please just say so. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223507 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <2veq3214birv21c9r8iol2kq20ha4jsi4r@4ax.com> <5nfq321v4ue0h1hlgcobbsj6g5b68hhmn0@4ax.com> Message-ID: Date: Wed, 12 Apr 2006 21:01:25 GMT Richard Clark wrote: > Cecil Moore wrote: >>It doesn't cost anything to be paranoid. :-) > > You must have a Xerox bulk copy rate. I got a free printer with my new Dell computer. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223508 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Grounding Bar Length For Receiving Only Antenna Date: Wed, 12 Apr 2006 14:07:49 -0700 Message-ID: <123qr18phc9aab5@corp.supernews.com> References: <1144784784.419166.221570@j33g2000cwa.googlegroups.com> Ed Bailen wrote: > I don't know that I buy your statement that ground losses aren't > extremely important for receiving applications. Antenna systems are > bi-directional. If you lose xdB of transmitted sigal due to ground > losses, then you are also going to lose xdB of received signal due to > ground losses. Your statement about the "bi-directionality" (usually called reciprocity) of antennas is true. But what counts when receiving is the signal to noise ratio. If you lose x dB at the transmitter, the person receiving the signal gets a signal that's now x dB lower than it was before, and the noise is the same. So the S/N ratio has been reduced by x dB. Therefore it's desirable to minimize loss at the transmitter antenna. But what happens when the receive antenna has x dB loss? At HF, the dominant source of noise is atmospheric (and QRM). Adding x dB loss at the receive antenna reduces both the signal *and* the noise by x dB. The result is the same S/N ratio as before. That's why efficiency isn't important for HF receiving antennas. Of course, you could reach a point where the efficiency is so bad that the receiver noise dominates. Beyond that point, lowering receive antenna efficiency will reduce S/N ratio. But this point is usually a long way down. Likewise, at VHF and above, where atmospheric noise is low and receiver noise dominates, high receive antenna efficiency is desirable. But the original question was, I believe, in reference to HF receiving. > A more important issue is that ground losses are very important when > receiving a lightning strike. It may be effective to bury several > runs of bare #6 copper in trenches radiating from your "ground > point". The QTH here is located on a solid rock slab. All grounding > is through buried #6 wires and a few ground rods driven laterally > between the rock layers up by the tower base. Lightning protection and mains safety grounding are separate issues with somewhat different requirements. Although a good lightning ground probably usually constitutes a reasonably efficient RF ground, that's not always the case, and the reverse isn't necessarily true either. Roy Lewallen, W7EL Article: 223509 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Wed, 12 Apr 2006 21:14:17 GMT Gene Fuller wrote: > I will retain the entire message below, so that I am not accused of > misattribution. Gene, to the best of my knowledge, you have never misattributed anything. > Where did you get this idea that the velocity factor is constant? The equation for velocity factor includes coil diameter, turns per inch, and wavelength. Keeping the coil diameter constant, the turns per inch constant, and the wavelength constant should ensure that the velocity factor is constant. > Specifically, why is the velocity factor of a resonant coil the same as > the velocity factor of a significantly shorter coil? It is pretty well > accepted that the inductance of coils does not scale linearly with the > length of the coil. Therefore any arguments about based on direct > calculation of Vf from L and C would seem to fail to support your model. You are obviously mistaken. If you increase the L by lengthening the coil, you have also increased the C by the same percentage. The L and C for any unit length are the same no matter how long the coil or transmission line is. > " . . . an approximation for M has been determined by Kandoian and > Sichak which is appropriate **for quarter-wave resonance** and is valid > for helices . . ." Yes, but if one doesn't change the frequency or the diameter or the turns per inch, the approximation should hold since nothing in the VF equation changes by shortening the coil. One should be able to shorten or lengthen the coil andmaintain the same VF. Seems it is up to you to prove what you are saying. Please prove that the ratio of L to C ratio of a coil changes with length. That should be an interesting proof. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223510 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Message-ID: Date: Wed, 12 Apr 2006 21:22:20 GMT John Popelish wrote: > Cecil Moore wrote: >> What does it mean to the E-fields and H-fields to say >> the voltage is leading the current? > > It means that the current at both ends of the coil was delayed (relative > to its phase if the coil had not been there). It means that there was a > voltage difference across the ends of the coil that drove that current > through the coil. In order to avoid any delay through the coil, you propose a delay in the one inch of wire at the bottom of the coil? Does that really make sense to you? How is this magic delay accomplished? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223511 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> <%pc%f.69283$dW3.66938@newssvr21.news.prodigy.com> <6Rd%f.6028$1q4.4181@bgtnsc05-news.ops.worldnet.att.net> Message-ID: Date: Wed, 12 Apr 2006 21:31:11 GMT Gene Fuller wrote: > You spent a lot of time developing the "10 degree" model for the > bugcatcher coil. Yes, it was a waste of time since I didn't accomplish the goal of eliminating reflections. The phase angle between the source voltage and source current is 71 degrees. That proves that I failed to eliminate reflections. > You keep referring everyone to the now famous gif image on your web > page. The question becomes why is EZNEC correct in supporting your > position at some times and incorrect when it does not support your > position at other times? EZNEC doesn't differentiate between standing waves and traveling waves. The user has to ensure there are no reflected waves. I failed in that task. It's no big deal. I fail quite often. My position is technical facts and accuracy. What is your position? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223512 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144787795.664748.325710@z34g2000cwc.googlegroups.com> <1144841185.770853.143110@i40g2000cwc.googlegroups.com> <2veq3214birv21c9r8iol2kq20ha4jsi4r@4ax.com> <5nfq321v4ue0h1hlgcobbsj6g5b68hhmn0@4ax.com> <8Pd%f.67947$Jd.27312@newssvr25.news.prodigy.net> <1144876390.898187.120660@z34g2000cwc.googlegroups.com> Message-ID: Date: Wed, 12 Apr 2006 21:33:41 GMT K7ITM wrote: > Like I posted earlier today, Tom, all of this provides an interesting > window into Cecil's mind. Tom, I find it strange that you are defending your violation of newnews attribution guidelines. What other unethical activities do you defend? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223513 of rec.radio.amateur.antenna Subject: Re: Balloon lifted wire antenna? References: From: dougmc@frenzy.com (Doug McLaren) Message-ID: Date: Wed, 12 Apr 2006 21:35:22 GMT In article , N7ZZT - Eric Oyen wrote: | would you care to explain that????? | | conversely, Hydrogen is: | Element 1 | atomic weight: 1.00794 Of course, in the context of a balloon, it's important to remember that atomic hydrogen is not generally found -- instead, you see H-H or H2 molecules, so hydrogen gas is approximately 1/2 as dense as helium, not 1/4 as dense. (Of course, others have already mentioned this.) | Number of Protons/Electrons: 1 | Number of Neutrons: 0 | | hydrogen is also known to have *at least* 5 known isotopes (all unstable and | all prone to radioactive decay). Well, the most common isotope of hydrogen, which is just a proton with no neutrons (and is called protium when you need a name), is NOT prone to radioactive decay. Neither is deuterium, for that matter. According to http://en.wikipedia.org/wiki/Isotopes_of_hydrogen, seven isotopes of hydrogen have been found, but the first two, protium and deuterium are stable, the third, tritium is unstable but not extremely so (half life = 12 years.) The rest are extremely unstable and not naturally occurring in any signifigant degree if at all. Though I'm not sure what any of this has to do with a balloon or blimp -- protium is 6500 times more common than deuterium, and tritium is much much less common than that. Just assume your balloon has normal hydrogen in it. I wonder how the local CCR would react to me putting up a large HF antenna with a balloon ... poorly, I imagine :) -- Doug McLaren, dougmc@frenzy.com, AD5RH For lucky best wash, use Mr. Sparkle! Article: 223514 of rec.radio.amateur.antenna From: Ian Jackson Subject: Re: Improving FM in building Date: Wed, 12 Apr 2006 23:05:05 +0100 Message-ID: References: <2bf27$443d1c89$45011502$10556@KNOLOGY.NET> In message <443D5362.A5E09CCD@shaw.ca>, Irv Finkleman writes >amdx wrote: >> >> The health club I belong to has poor FM reception inside the building. >> I'm trying to get them to improve it. The thought I have is to install >> an outside omni antenna and connect it to an inside identical antenna >> hanging down from the ceiling. >> Is this a workable idea? >> Does anyone have info to help make the improvements? >> >> Thanks >> Mike >> PS---This is for all the personal FM radios worn by the exercisers. > >If they have cable TV in the club you can put a set of rabbit ears >in one of the outlets and see if that helps. A preamp may help too. > >Irv VE6BP Irv, Have you any idea about the lengths which cable TV operators go to to keep their networks RF-tight (ingress and egress)? Feed an outlet into antenna? Maybe not such a good idea!! Ian. -- Article: 223515 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: Improving FM in building Date: Wed, 12 Apr 2006 23:31:33 -0000 Message-ID: <123r3elclpl87e2@corp.supernews.com> References: <2bf27$443d1c89$45011502$10556@KNOLOGY.NET> <443D5362.A5E09CCD@shaw.ca> In article , Ian Jackson wrote: >>If they have cable TV in the club you can put a set of rabbit ears >>in one of the outlets and see if that helps. A preamp may help too. >Irv, >Have you any idea about the lengths which cable TV operators go to to >keep their networks RF-tight (ingress and egress)? Feed an outlet into >antenna? Maybe not such a good idea!! Yeah, that's likely to cause problems. The rabbit ears will "leak" signals that the cable company has no right to be broadcasting... some of the cable channels overlap with air-traffic control frequencies, amateur radio, and so forth. Complaints are likely to arise, either because the egress leakage from the cable through the rabbit ears interferes with licensed radio services, or because a licensed transmitter somewhere in the area of the club leaks back into the cable and wipes out TV reception for other cable customers. Upon locating the source of the problem, the cable company *might* be polite enough to simply insist on disconnecting and terminating the cable outlet in question. Or (depending on how irritated their Cable Guy is that day) they might just cut off the cable service to the club entirely. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! Article: 223516 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: <4Ng%f.138$732.128@fe10.lga> Date: Wed, 12 Apr 2006 20:17:52 -0400 "Roy Lewallen" wrote in message news:123qihrf94k80e8@corp.supernews.com... > Yuri Blanarovich wrote: >> >> Oooops, carefull here. >> As far as I know, nobody has claimed that inserted loading coil replaces >> the "missing" degrees of the radiator in terms of providing magical >> properties that would look like that "replaced" portion of the antenna, >> or make the antenna act like 90 degree full size physical radiator. > > Agreed, it's not quite stated as such. Here are some statements which were > made: > > From your web page http://www.k3bu.us/loadingcoils.htm, in bold type: > > "In summary: > The current in a typical loading coil in the shortened antennas drops > across the coil roughly corresponding to the segment of the radiator it > replaces." > > By Cecil, on March 5, on this newsgroup: > > "A loading coil thread is climaxing over on qrz.com. I have > used EZNEC to generate a graphic which shows a 3/4WL vertical > and a similar 1/2WL vertical with a ~1/4WL loading coil. The > loading coil is a wire helical coil containing (surprise) > roughly 1/4WL of wire. The coil does a good (not perfect) > job of replacing 1/4WL of wire. Many things can be gathered > from observation of the current reported by EZNEC for the > two antennas. The coil occupies roughly the same number > of degrees of the antenna as the wire it replaces. The > current at the top and bottom of the coil is roughly the > same as the current at the two ends of the wire it replaces. > Is the coil an exact replacement? Of course not." > >> What we are saying that the loading coil appears to replace "missing" >> electrical degrees of the radiator in order to make it resonant, that is >> back to 90 electrical degrees (has to be in order to resonant), which >> rest of the existing "straight" radiator forces it to do (+/-). > > It's getting muddier and muddier just what you mean by "replace". Nobody > has questioned that a loading coil makes the antenna resonant; that's its > purpose. But that's simply an impedance transformation property which can > be accomplished well away from the antenna by many different methods. > Roy, the above are the attempts to illustrate and add some more to understanding and reasoning why the current across (alonng) the loading coil, roughly half way or 2/3 up the resonant quarter wave radiator is larger at the bottom and drops about 40 - 60% at the top. While one side argues that it is (almost) the same, we argue that it drops. That is the argument and not detours to degrees, phasors, and rest of the mud that was rehashed here. >> Radiation properties and efficiency of the loaded antenna is proportional >> to the area under the current curve. It is obvious to anyone comparing >> the area under the current curve of full size quarter wave radiator vs. >> loaded radiator that there is huge difference in area under the curve and >> performance, efficiency, which is known and been verified by numerous >> measurements. >> HOW the current curve is modified by different loadings and position >> along the radiator is important in knowing how the current distribution >> curve along the radiator is modified. > > I agree with all this. I'm glad you've clarified this for the benefit of > posters like the one to whom my recent posting was directed. > >> The whole controversy is that "gurus" claim current doesn't drop across >> the coil, while we say that it does, therefore making the area under >> current curve above the coil smaller and effciency of loaded antenna >> worse than they believe and insist on. > > I don't think you'll have any trouble winning your arguments against your > imaginary "gurus", whomever and whatever they might be. Over two years ago > I made careful measurements which showed a current difference between the > top and bottom of a loading coil. Cecil posted an EZNEC model on his web > site showing a substantial difference. I've commented on it several times, > explaining the reason for the difference, and modifying the model to > illustrate the explanation. > If I remember correctly you inserted the coil at the base and I am not sure if it was resonant quarter wave radiator. Can you describe the setup, length and frequencies used? You should try to use quarter wave resonant radiator with coil about 1/2 to 2/3 up the mast and tell us what the current values are. W9UCW has pictures and data measured, we should try to emulate this situation, that is the object of controversy. Cecil mentioned cases when current can be the same, or lower at the top, or bottom, depending where the same coil is placed in relation to the standing wave and current distribution on the radiator. Are you denying that this is the case or something wrong with W9UCW test setup and results? > The controversy is in the explanation of the difference. It simply doesn't > require Cecil's theories. I've never been able to tell exactly what your > theory is, if you indeed have one. > The controversy is about the claims that the current at the ends of the typical loading coil is the same or different in range of 40 -60% drop. Its not my theory, it is the reality that we are trying to bring forth and correct misconceptions that are obviously floating around since 1953. My approximation and explanation (latest) I mentioned is in one of my posts in reply to W8JI "arguments" (to do with impedances). >> Again, when applied in modeling programs, wrong assumption will produce >> erroneous results, which will be magnified in multielement antenna >> designs. >> So the "gurus" basically ignore behavior of coil in the standing wave >> environment along the loaded radiator, where the current drops from max >> at base to zero at the tip, but coil would magicaly resist that, because, >> bla, bla, bla.... (see their "reasons") > > Would you name these "gurus" so we can read their postings and see what > you're talking about? > Mostly the "equal current camp". >> So while everyone knows (?) that standing wave current drops acros >> (along) the wire (all the antenna books show that), but it is >> "impossible" to drop along the coiled wire (real inductance - coil, >> loading stub). Reality and measurments prove that, but according to them >> "it can't be so". >> >> I am already gathering necessary hardware to do more experiments, >> measurements to show what is really happening, and will prepare articles >> how to model and apply it to antenna design. >> I would challenge the "unbelievers" to join me and repeat the tests, to >> see wasaaaap. > > You'll be surprised when everyone agrees that there's a current difference > between the top and bottom of the coil. Unless your "gurus" show up, > whomever they are. > > I've already made a test and posted the results, over a year ago. When it > failed to show a current difference anywhere near the number of degrees it > "replaced", your complaint was that I was using an inductor which was too > small physically. So obviously your theory works only on certain size > inductors. Once you or Cecil has the theory fully worked out, it should be > able to not only tell us what the current difference between top and > bottom should be, but also how physically large an inductor must be before > the theory works. And why it doesn't work for physically small inductors. > I have not verified it, but W9UCW claims using ferite inductor and got very similar results. I believe your test, you used coil near the base. I will run test with different inductors from bugcatcher type, "no good" Hustler, to ferite and in different positions. > Those of us stuck with old fashioned conventional theory can explain the > drop for small as well as large coils, so you folks have a bit of catching > up to do. > Looks like the size of the coil has small effect on current variation (unless high resistance). Position of the coil in relation to current distribution along the radiator would cause equal (special case), less on the top of coil or more, depending where on the standing wave curve coils is located. In our case we are arguing about 2/3 up the resonant radiator. > I think a lot of the experimental work can be done by modeling. I'd be > interested in hearing of any cases where measured results differ > significantly from EZNEC results. Incidentally, your web page is a bit > outdated in that respect, apparently being written before EZNEC v. 4.0 was > available with its automated helix creation feature. > Now with solenoid generation in EZNEC 4.0 it helps to get away from the lumped inductance and it shows that there is current drop, reflecting situations in question. Also the loading stub produces similar results. Cecil showed the cases and with different positions along the current curve, demonstrated in EZNEC huge differences in current at the ends of the coil. But this is getting strangely ignored and instead we get all kinds of "reasons" why it can't be. I am sorry I dropped out of this due to AOL dropping NG, and I thought that reality would be understood by now. Only when Cecil told me that subject flared up again and nothing changed, I rejoined the discussions. I think really at this point, it is beating the dead horse. I will do the tests and write it up. I will try to corellate the tests with modeling in EZNEC. If someone denies the reality, that's their choice. I will post the progress on my web page. I can't stomach W8JI "exchanges" any more. No answer to questions or following the points, just twist and jive. > Roy Lewallen, W7EL I didn't look it up, but is there way in EZNEC to know or calculate the inductance of modeled solenoid? Or better, specify the inductance and let the EZNEC "make" the coil of prescribed diameter and TPI? 73, Yuri Blanarovich, K3BU Article: 223517 of rec.radio.amateur.antenna Date: Wed, 12 Apr 2006 19:26:36 -0500 From: Tom Ring Subject: Re: Current across the antenna loading coil - from scratch References: <1144715023.730193.164820@i39g2000cwa.googlegroups.com> <17929-443B29E8-742@storefull-3255.bay.webtv.net> <1144770324.537592.101610@t31g2000cwb.googlegroups.com> <1144784891.274341.118940@z34g2000cwc.googlegroups.com> <1144793465.690849.152810@g10g2000cwb.googlegroups.com> <2vlo325r080645tk7m23rjbv0tunkm4knb@4ax.com> <123osonj6puofe0@corp.supernews.com> Message-ID: <443d9abd$0$76686$39cecf19@news.twtelecom.net> David G. Nagel wrote: > Wes Stewart wrote: > >> >> Responding to no one in particular. >> >> This is starting to make me miss the shorter Fractenna threads. >> Phil, comeonback good buddy. > > > > They certainly made more sense. > > Dave N Although there is a large difference - this is an arument over how soemthing that works works. The other was about _whether_ the thing works. tom K0TAR Article: 223518 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1144704127.759376.293850@e56g2000cwe.googlegroups.com> <1144813345.585052.29750@t31g2000cwb.googlegroups.com> Subject: Re: JOHN CHIPMAN OWNER OF CHIPMAN RELOCATIONS UNITED VAN LINES MAYFLOWER CATON MOVING & STORAGE likes to make many harassing/harassment phone calls Message-ID: Date: Wed, 12 Apr 2006 17:39:49 -0700 "Howard W3CQH" wrote in message news:J-OdnWTCBqWE16DZRVn-pw@adelphia.com... > Why do you cross post this garbage to everybody? Apparently you don't have > a life! > > > "studley the bull" wrote in message > news:1144813345.585052.29750@t31g2000cwb.googlegroups.com... > > > > are we having fun yet wrote: > >> JOHN CHIPMAN OWNER OF CHIPMAN In fact, the poster rarely sees our reactions. (Think of the "driveway drop" circulars that show up at every home; nobody waits and watches to see you react to reading them.) Article: 223519 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <2bf27$443d1c89$45011502$10556@KNOLOGY.NET> <1144858162.935757.60290@z34g2000cwc.googlegroups.com> Subject: Re: Improving FM in building Message-ID: Date: Wed, 12 Apr 2006 17:47:09 -0700 wrote in message news:1144858162.935757.60290@z34g2000cwc.googlegroups.com... > It might work OK, especially if the building is really sealed tight to > RF. > > You may want to add a cheap FM preamp with the outside antenna > connected to the input and the inside antenna connected to the output, > so that the connection between the antennas has a tad of gain, rather > than just loss. > > Dan > N3OX > This works for GPS. I had a project at China Lake Naval Weapons Center a few yeards ago, where they pumped GPS through an amp and rebroadcast it in the lab where they were evaluating a missile guidance syatem. (It doesn't matter how sure I was that there was no fuel and no warhead in the missile; I did NOT like walking in front of that thing.) Article: 223520 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Message-ID: Date: Thu, 13 Apr 2006 00:53:26 GMT John Popelish wrote: > If you don't believe me, simulate it with EZNEC. Connect a source to a > parallel combination of C and R. Record the phase of the current with > respect to the voltage (the current will lead). Then add a series > inductance that cancels the capacitance, and the current will be delayed > till it matches the phase of the applied voltage. Power factor corrected. The "current will be delayed"? That cannot be, according to W8JI and W7EL. They say there is no more delay through a 6" coil than through a 6" wire. That's what the argument is all about. Instead of the current being delayed, their voltage jumps ahead in time at greater than the speed of light in order to correct that power factor. -- 73, Cecil http://www.qsl.net/w5dxp Article: 223521 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Wed, 12 Apr 2006 18:24:32 -0700 Message-ID: <123ra2kngip1a54@corp.supernews.com> References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> <4Ng%f.138$732.128@fe10.lga> Yuri Blanarovich wrote: > > Roy, > the above are the attempts to illustrate and add some more to understanding > and reasoning why the current across (alonng) the loading coil, roughly half > way or 2/3 up the resonant quarter wave radiator is larger at the bottom and > drops about 40 - 60% at the top. While one side argues that it is (almost) > the same, we argue that it drops. That is the argument and not detours to > degrees, phasors, and rest of the mud that was rehashed here. You still haven't told us who this "side" is that argues that the current is the same at the bottom and top. I assume it's those unnamed "gurus" who you haven't identified. It shouldn't be a problem to show that the other "side" is wrong if it doesn't exist. >> > If I remember correctly you inserted the coil at the base and I am not sure > if it was resonant quarter wave radiator. Can you describe the setup, length > and frequencies used? You should try to use quarter wave resonant radiator > with coil about 1/2 to 2/3 up the mast and tell us what the current values > are. W9UCW has pictures and data measured, we should try to emulate this > situation, that is the object of controversy. Cecil mentioned cases when > current can be the same, or lower at the top, or bottom, depending where the > same coil is placed in relation to the standing wave and current > distribution on the radiator. Are you denying that this is the case or > something wrong with W9UCW test setup and results? You can find my earlier postings at groups.google.com. The results you're asking about were posted on Nov. 11, 2003. You can find your own comments about my measurements there also, on the same date. I'm sorry, but I don't have time to try and model or carefully analyze W9UCW's results. The results for a toroid show more current difference than I'd expect, and suspect that's due to the shunt capacitance of the physically large meters he was using. Before, you complained because the coil wasn't physically long enough. Now you want it placed somewhere else along the radiator. Sorry, after the reaction I got to my previous test, I have no interest at all in making additional ones. > > The controversy is about the claims that the current at the ends of the > typical loading coil is the same or different in range of 40 -60% drop. Its > not my theory, it is the reality that we are trying to bring forth and > correct misconceptions that are obviously floating around since 1953. My > approximation and explanation (latest) I mentioned is in one of my posts in > reply to W8JI "arguments" (to do with impedances). The only posting I see that fits that description is your posting on this thread on April 7. As I read it, you say that as you put a coil higher and higher in an antenna, the inductance required to maintain resonance increases, and the difference in current between the bottom and top of the coil increases as the coil is made larger. I don't see any values or way of calculating them, but don't have any disagreement with the qualitative statements you made there. [Yuri wrote:] >>> Again, when applied in modeling programs, wrong assumption will produce >>> erroneous results, which will be magnified in multielement antenna >>> designs. >>> So the "gurus" basically ignore behavior of coil in the standing wave >>> environment along the loaded radiator, where the current drops from max >>> at base to zero at the tip, but coil would magicaly resist that, because, >>> bla, bla, bla.... (see their "reasons") [I wrote:] >> Would you name these "gurus" so we can read their postings and see what >> you're talking about? >> [Yuri wrote:] > Mostly the "equal current camp". I take that as a "no", you can't name the "gurus". The advantage of arguing against imaginary "gurus" is that you can have them claim anything you want. It shouldn't have taken you so many postings to prove them wrong. > I have not verified it, but W9UCW claims using ferite inductor and got very > similar results. I believe your test, you used coil near the base. I will > run test with different inductors from bugcatcher type, "no good" Hustler, > to ferite and in different positions. Then you and Cecil have quite different theories, it seems. His doesn't predict the drop I measured. Those of us who are tired of the endless arguments should sit back and let you and Cecil go at it until you come to an agreement. > Looks like the size of the coil has small effect on current variation > (unless high resistance). Position of the coil in relation to current > distribution along the radiator would cause equal (special case), less on > the top of coil or more, depending where on the standing wave curve coils is > located. In our case we are arguing about 2/3 up the resonant radiator. I don't know who "we" is. The technical theory I subscribe to doesn't require any particular placement of the coil. > Now with solenoid generation in EZNEC 4.0 it helps to get away from the > lumped inductance and it shows that there is current drop, reflecting > situations in question. Also the loading stub produces similar results. > Cecil showed the cases and with different positions along the current curve, > demonstrated in EZNEC huge differences in current at the ends of the coil. > But this is getting strangely ignored and instead we get all kinds of > "reasons" why it can't be. I replaced the whip in one of Cecil's models with a lumped RC and got the same result. Then I eliminated the ground and reduced the current drop to near zero. I've commented on that on several occasions. That certainly doesn't constitute "strangely ignoring" Cecil's model. > I am sorry I dropped out of this due to AOL dropping NG, and I thought that > reality would be understood by now. Only when Cecil told me that subject > flared up again and nothing changed, I rejoined the discussions. I think > really at this point, it is beating the dead horse. I will do the tests and > write it up. I will try to corellate the tests with modeling in EZNEC. If > someone denies the reality, that's their choice. I will post the progress on > my web page. Let us know when it's available. Hopefully it'll actually happen this time. Again, I'll be interested in knowing of any significant difference between modeling and measurement results. > I can't stomach W8JI "exchanges" any more. No answer to questions or > following the points, just twist and jive. Funny, that's just the way most of your postings appear to me and, I'm sure, to Tom. > I didn't look it up, but is there way in EZNEC to know or calculate the > inductance of modeled solenoid? Or better, specify the inductance and let > the EZNEC "make" the coil of prescribed diameter and TPI? The answer to your second question is no. To your first, yes. What I've done is model the inductor in free space with ends extended to the helix axis (an option when creating it). Put a wire end-to-end down the center of the coil with a source in the middle. Src Data will show you the reactance, from which you can get the inductance. This seems to work reasonably well provided that the frequency is low enough that the coil is well below self resonance and low enough that it doesn't radiate much but high enough that NEC-2 doesn't have trouble with the loop size. If it shows good results in the Average Gain test, it's probably ok. Roy Lewallen, W7EL Article: 223522 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> <4Ng%f.138$732.128@fe10.lga> <123ra2kngip1a54@corp.supernews.com> Subject: Re: Current across the antenna loading coil - from scratch Message-ID: Date: Wed, 12 Apr 2006 23:07:20 -0400 "Roy Lewallen" wrote >> K3BU wrote: I can't stomach W8JI "exchanges" any more. No answer to >> questions or following the points, just twist and jive. > > Funny, that's just the way most of your postings appear to me and, I'm > sure, to Tom. > Then there is your answer to who is "gurus" and who is "we". "Gurus" know that current in loading coil is the same. "We" know, measured it properly and argue that that is significantly different. I am sorry, you are wrong. I tried to follow some stepts to get to the point, Tom ignores my points and jumps to lecture how, bla, bla... I am really done here, you guys can believe what you want. Just that reality doesn't jive with your "can't be". 73 Yuri Article: 223523 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Current across the antenna loading coil - from scratch Date: Wed, 12 Apr 2006 20:09:09 -0700 Message-ID: <123rg6prdklphe0@corp.supernews.com> References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> Mike Coslo wrote: > Roy Lewallen wrote: > >> That this concept is wrong can and has been shown by theory, modeling, >> and measurement. I made and posted measurements on this newsgroup in >> November 2003 which demonstrated clearly that the presumption is false. > > Okay. It looks like we have at least some measurements that differ. > Any idea why that would be? The amount the magnitude of the current drops across an inductor is determined primarily by the amount of inductance and the capacitance >from the inductor to ground or the other half of the antenna. This is easily explained by simple lumped constant circuit theory. There's also some variation due to radiation and imperfect coupling between turns. In the extreme case of a very loose helix, coupling is poor and radiation is high, so the helix acts more like a wire than an inductance. This requires a more complex analysis, but that's also in the realm of well known phenomena. With this wide variation in physical possibilities, different results can't be avoided. What some of us have tried to do is explain why the results occur. I don't know of differing results from the same physical setup, but it could surely happen. Making good measurements isn't a trivial task. > Do you remember the name of the thread? Current in antenna loading coils controversy (long). I made two sets of measurements. The second was posted on Nov. 11, 2003 and the first a few days earlier. >> The loading coil isn't making the antenna act like a physically longer >> antenna. In the extreme case of a physically short inductor at the >> feedpoint, it's simply modifying the feedpoint impedance and has no >> effect whatever on the antenna's radiation. > > Would the inductor then be best right past the feedpoint? Certainly > having the inductor at the far end, or in the middle seems like a bad > place for it. (not talking about trap antennas) Generally not, but it depends on several factors. Moving the coil upward increases the radiation resistance of the system, which improves efficiency in the presence of ground loss. However, it also requires a larger coil, so the coil's resistance is greater. But the current at the location of the coil is lower, so overall I^R loss of the coil is often less with the coil somewhere around halfway up. The relative amount of coil and ground loss, as well as the amount of top loading if any, are all factors in determining which position is best. This is really a separate question, and I don't have varied enough experience with HF mobile setups to be anywhere near an expert. Tom, W8JI, is though. You can take what he says on the subject to the bank. Roy Lewallen, W7EL Article: 223524 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <1144881497.087046.72490@e56g2000cwe.googlegroups.com> Message-ID: Date: Thu, 13 Apr 2006 03:10:27 GMT w8ji@akorn.net wrote: > An inductance changes the relationship between phase of voltage and > current, NOT current through the inductance from terminal to terminal. That's true only for a lumped inductance which doesn't exist in reality. > Yuri again distorts fact. What everyone is saying is there can be a > current change, but it is not caused by standing waves or missing > antenna area. It is caused by displacement current, and so can have a > wide range of change in a given antenna. In the graphic at: http://www.qsl.net/w5dxp/test316.GIF in the right hand configuration the current at the bottom of the coil is 1.3 amps and the current at the top of the coil is 2.1 amps. Your explaination for more current at the top of the coil than at the bottom is that 0.8 amps of displacement current is jumping up from earth ground into the side of the coil and flowing out the top? Would you please describe that bit of magic in a little more detail? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223525 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> <4Ng%f.138$732.128@fe10.lga> <123ra2kngip1a54@corp.supernews.com> Message-ID: Date: Thu, 13 Apr 2006 03:23:20 GMT Roy Lewallen wrote: > Then you and Cecil have quite different theories, it seems. His doesn't > predict the drop I measured. The current can be a DROP or a RISE or EQUAL depending upon where it is installed in the standing wave environment. > That > certainly doesn't constitute "strangely ignoring" Cecil's model. You have completely ignored the EZNEC results posted at: http://www.qsl.net/test316.GIF where the current at the top of the coil is greater than the current at the bottom of the coil. How would your theory handle a current RISE through a coil? -- 73, Cecil http://www.qsl.net/w5dxp Article: 223526 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <1144708348.601210.298690@e56g2000cwe.googlegroups.com> <4nB_f.67497$Jd.30975@newssvr25.news.prodigy.net> <5nC_f.5711$YT1.592@bgtnsc04-news.ops.worldnet.att.net> <6ZF_f.64716$H71.32645@newssvr13.news.prodigy.com> Message-ID: Date: Thu, 13 Apr 2006 03:44:11 GMT Cecil, I gave you a very specific reference to demonstrate your supposition was incorrect. You came back with nothing but, "Because I say so." You have not offered one shred of backing for your constant Vf argument. And it is up to ME to further prove something? I don't think so. 73, Gene W4SZ Cecil Moore wrote: > Gene Fuller wrote: > >> I will retain the entire message below, so that I am not accused of >> misattribution. > > > Gene, to the best of my knowledge, you have never > misattributed anything. > >> Where did you get this idea that the velocity factor is constant? > > > The equation for velocity factor includes coil diameter, > turns per inch, and wavelength. Keeping the coil diameter > constant, the turns per inch constant, and the wavelength > constant should ensure that the velocity factor is constant. > >> Specifically, why is the velocity factor of a resonant coil the same >> as the velocity factor of a significantly shorter coil? It is pretty >> well accepted that the inductance of coils does not scale linearly >> with the length of the coil. Therefore any arguments about based on >> direct calculation of Vf from L and C would seem to fail to support >> your model. > > > You are obviously mistaken. If you increase the L by lengthening > the coil, you have also increased the C by the same percentage. > The L and C for any unit length are the same no matter how long > the coil or transmission line is. > >> " . . . an approximation for M has been determined by Kandoian and >> Sichak which is appropriate **for quarter-wave resonance** and is >> valid for helices . . ." > > > Yes, but if one doesn't change the frequency or the diameter or > the turns per inch, the approximation should hold since nothing > in the VF equation changes by shortening the coil. One should be > able to shorten or lengthen the coil andmaintain the same VF. > > Seems it is up to you to prove what you are saying. Please prove > that the ratio of L to C ratio of a coil changes with length. That > should be an interesting proof. Article: 223527 of rec.radio.amateur.antenna From: Gene Fuller Subject: Re: Current across the antenna loading coil - from scratch References: <1144647060.456337.126840@e56g2000cwe.googlegroups.com> <3989-443A71AB-132@storefull-3256.bay.webtv.net> <123orli9a52nr5e@corp.supernews.com> <123qihrf94k80e8@corp.supernews.com> <4Ng%f.138$732.128@fe10.lga> <123ra2kngip1a54@corp.supernews.com> Message-ID: Date: Thu, 13 Apr 2006 03:46:40 GMT Cecil Moore wrote: > > You have completely ignored the EZNEC results posted at: > http://www.qsl.net/test316.GIF where the current at the top > of the coil is greater than the current at the bottom of the > coil. How would your theory handle a current RISE through a > coil? Cecil, Do you suppose that maybe the displacement current can actually work in either direction? Did someone put a diode in the aether? 73, Gene W4SZ