Article: 224899 of rec.radio.amateur.antenna From: "R. Scott" Subject: Re: Mobile rigging Message-ID: References: Date: Wed, 31 May 2006 14:28:10 GMT "Jerseyj" wrote in message news:jerseyj69-12602D.06051131052006@comcast.dca.giganews.com... > Hi all, > Just got a new 2006 Forrester and want to get my 2M/440 rig mounted > along with a mag mount antenna. Someone pointed me to the "rig of the > month" web site, but that site appears dead.. > > Anyone have any web sites that I can look at for information on setting > up my radio in my car ? Looks like K2BJ pulled the plug on the Mobile pages. Twas nice site too. Article: 224900 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: New program. Dipole+Line+Balun+Tuner Message-ID: <1lmr72p1ofrs3ncickuq3da3afs5s228j9@4ax.com> References: Date: Wed, 31 May 2006 18:06:32 GMT On Wed, 31 May 2006 00:58:58 +0100, "Reg Edwards" wrote: >New Program : LINELEN.exe > >This program calculates dipole feedpoint impedance, transmission line >input impedance, and balun input impedance, versus frequency. > >Dipole and line can be of any length. Line Zo can be of any >impedance. > >Power lost in antenna and line is calculated. Also overall loss. > >In addition to its educational value, this program will assist users >to change line length when the impedance presented to the tuner is >beyond its capability to transform it to a resistive 50 ohms. > >Download self-contained program LINELEN, file size = 53 K-bytes, from >website below. >---- >........................................................... >Regards from Reg, G4FGQ >For Free Radio Design Software go to >http://www.btinternet.com/~g4fgq.regp >........................................................... > For the Wireman's ladderline # 551, where would I find the line loss at 10 mhz in db per 100 feet (and why feet, when the other parameters are in meters?)? bob k5qwg Article: 224901 of rec.radio.amateur.antenna From: Buck Subject: Re: toot tone Message-ID: <25nr7251ugqbp79miveaqrk56og9uuumkh@4ax.com> References: Date: Wed, 31 May 2006 14:13:24 -0400 On Wed, 31 May 2006 11:30:47 -0500, "Tom" wrote: >Do any of you out there know where I can get one of these things mentioned >on this site? > >http://www.alldumb.com/item/27369/ > What is all the nonsense that the site was trying to conduct on my system? It crashed half a dozen times. -- 73 for now Buck N4PGW Article: 224902 of rec.radio.amateur.antenna From: Allodoxaphobia Subject: Re: toot tone Date: 31 May 2006 18:18:39 GMT Message-ID: References: On Wed, 31 May 2006 11:30:47 -0500, Tom wrote: > Do any of you out there know where I can get one of these things mentioned > on this site? > > http://www.alldumb.com/item/27369/ That domain is well named. But, your 'needs' are off topic in this antenna ng. I think you want to ask in rec.radio.cb.cretins. It's the sort of thing they would use for their 'roger-beep'. Article: 224903 of rec.radio.amateur.antenna From: "Old Ed" References: Subject: Re: New program. Dipole+Line+Balun+Tuner Message-ID: Date: Wed, 31 May 2006 19:08:26 GMT Hi Reg, Thank you for making yet another of your projects available to the group! But I am curious: What program inputs are required to calculate losses for tuners and baluns? Schematics? ;-) Coil Q? Wire type and gauge? Loss factors for ferrites? And how would one KNOW these parameters for real-world examples, say a Palstar AT-1500DT versus an Ameritron ATR-30? Ed "Reg Edwards" wrote in message news:SKednQ6g3qpAfeHZRVnytQ@bt.com... > New Program : LINELEN.exe > > This program calculates dipole feedpoint impedance, transmission line > input impedance, and balun input impedance, versus frequency. > > Dipole and line can be of any length. Line Zo can be of any > impedance. > > Power lost in antenna and line is calculated. Also overall loss. > > In addition to its educational value, this program will assist users > to change line length when the impedance presented to the tuner is > beyond its capability to transform it to a resistive 50 ohms. > > Download self-contained program LINELEN, file size = 53 K-bytes, from > website below. > ---- > ........................................................... > Regards from Reg, G4FGQ > For Free Radio Design Software go to > http://www.btinternet.com/~g4fgq.regp > ........................................................... > > Article: 224904 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: Brainteaser Date: Wed, 31 May 2006 13:16:08 -0700 Message-ID: References: <20319-44762304-243@storefull-3258.bay.webtv.net> Cecil Moore wrote: > "Jim Kelley" > wrote: > > Very nice, Cecil. It would be also > > useful to know how you obtained these > > numbers. > The same way you obtained your numbers, Jim, when you said: > > > It follows that the initial reflection > > would be 50 watts. When we assume that > > everything is re-reflected from the > > source, then at two seconds the forward > > power at the front of the line would be > > 150 watts. At four seconds, 175 watts; > > six seconds, 187.5; eight seconds, > > 193.75, and so on. > Please note that your numbers and mine agree exactly. > Also please note that I posted those numbers days ago > on qrz.com under a brainteaser thread. I have the EXCEL > file if you or anyone else would like to have it. (In a > one second long transmission line, when the load reflects > 50 watts, it has essentially reflected 50 joules because > nothing changes during the following second.) I'm not saying I think there's anything wrong with your numbers. They're actually very......precise. You wrote something about a SG-AT autotuner, and that could have a tendency to lead someone to believe that you were claiming to have made measurements. I now understand that you didn't use an SG-AT autotuner or make any measurements. Thank you for clarifying that point so eloquently. > In fact, I'll present a challenge for you and everyone > else. Do you mean "everyone" - in the same sense that Gary Oldman intended in "The Professional"? :-) > In any one second long lossless transmission line > with any forward power and any reflected power, I defy > you to come up with an example where the number of joules > stored in the line is not equal to the forward power plus > the reflected power. Those joules are the joules sourced > by the generator that have not made it to the load. The > conservation of energy principle will have it no other > way. The laws of physics win once again. > -- Kinda melodramatic. I'm not sure who you're arguing with. I gotta tell ya though, it reminds me a little of one of those guys who stands out on the street corner shaking his fist and shouting at traffic. Ever try to converse with one of those guys? 73, ac6xg Article: 224905 of rec.radio.amateur.antenna Subject: Re: RF grounding methods for sailboats: A Summary From: chuck Date: Wed, 31 May 2006 16:44:40 -0400 Message-ID: <1149107678_2377@sp6iad.superfeed.net> References: <1148994725_36063@sp6iad.superfeed.net> <6ggr72509n8k0ulii7a3j574e6ogiuhrbp@4ax.com> Richard Clark wrote: > On Tue, 30 May 2006 09:21:56 -0400, chuck wrote: > >> If anyone spots any errors of fact or significant omissions, I'd welcome >> appropriate "recalibration". Thanks in advance. >> >> 1) Grounding plates >> >> Will not work if submerged as much as four feet > > Hi Chuck, > Hello Richard, Perhaps the context for the summary was unclear. My objective was simply to identify several existing recommendations for obtaining RF grounds on plastic and wood vessels over saltwater. Regrettably, I lack knowledge of any published theoretical or empirical comparison of these proposals that provides an objective, quantifiable measure of performance. > Don't know how you got this miss-impression. > That it will not work if submerged as much as four feet? From Roy's report on his NEC-4 modeling. It is presumably based on the known skin depth of RF at 14 MHz. >> 2) Wire in water >> >> A one-foot length of wire immersed near water surface is sufficient for >> near-perfect results based on W7EL's NEC-4 model results. Assumed >> performance is similar to grounding plate. > > This conclusion is conflict with the first, making it a mystery how > you came to either in summary. The focus on "water surface" is as > though you are trying to force it work like a pool of mercury. Water > is NOT a ground plane in the sense of conductivity. Water is a > terrible conductor. It is only its huge mismatch with air that gives > it such superb propagation, not match, characteristics. Distinguish > between the two. > Well, some of what you are saying is pretty much what I had thought. If you read my posts on the other thread, you'll see where I was heading. We agree that seawater's conductivity is lower than copper's but greater than earth's. We agree that a single ground rod driven into the earth will perform poorly as the only return path for a vertical antenna over land, but at least in some cases will perform better than if it were not there. Will a wire dipped into the sea perform better than the ground rod driven into the earth? I doubt there is much disagreement on that, even though water might be characterized in relative terms as a "terrible conductor". The only relevant question, then, is "how much better?" and so far, the only numerical answer that I am aware of has come from NEC modeling. The characterization I reported of a wire dipped into the sea is based on Roy's modeling, assuming I have not misunderstood of course. Others have made the same point, but now we have model results to support it. BTW, I have just discovered a response from Roy to one of my posts on the other thread that is available on Google, but has never shown up on either of the two newsgroup subscriptions I have. Roy addressed some of my concerns in that post so if you have not seen it you might do a search for it on Google. >> 3) Radials >> >> Even shortened (loaded) radials elevated over seawater work as >> near-perfect based on N6LF's NEC-4 modeling. Objections to radials are > > The objections are they are wholly unnecessary when ground is so > easily achieved by conventional means. You would need 120 radials to > shield against the loss you perceive, and that loss doesn't matter What loss is it that I perceive? N6LF's results show near lossless results with only four shortened radials over seawater. > when you stand to gain so much in propagation. You couldn't even > field a tenth of these radials. At HF, and maintaining their tune > and symmetry, you would be lucky to fit in 2. Other studies have shown a single elevated radial over land to lose less than one dB over a perfect ground plane. At that stage of the > game, there is absolutely no match advantage over conventional > techniques aboard a small craft (and at HF you don't qualify for any > thing other). >> 4) Counterpoise (i.e., mast, forestay, shrouds, lifelines, engine, metal >> tanks, 100 square feet of copper, keel, rudder, etc. bonded together) >> >> This type of >> counterpoise is also the approach recommended by both Icom and SGC. > > Only because it is already available and doesn't ask you to go any > further for no obvious advantage. > Well, what makes life interesting is that to advocates of the other approaches, there are obvious advantages. >> 5) OCF dipole w/horizontal component along deck >> >> Not commonly used, > > Who would choose a complicated design over so many simple ones? > Multiple resonant radials that cover the popular marine and ham bands on a small boat are not seen by all as simple. One might ask the same question of those who advocate the counterpoise approach, since the wire in the water is simpler. I think choosing the best system (broadly defined to also consider operation over fresh water and near-vertical radiation when important) will be easy if we can only get some objective, reproducible data and/or analysis. >> Is that where it stands, folks? > > If you want a dipole, make a VERTICAL dipole, even a lousy one. > Certainly worthy of consideration. Many backstay antennas are probably operated as half-wave vertical dipoles (end-fed, of course) above 10 MHz or so. > Finally, and to repeat, learn the distinction between matching and > propagation. Your focus on matching issues is like seeing your glass > 3/4ths empty. Looking at the propagation advantages in comparison is > like seeing a pitcher of water nearby that will fill that glass a > dozen times. I didn't address any matching issues at all that I can see, Richard. Sorry if I misled you. All of the alternatives utilize the same seawater for propagation and the same vertical radiator. They differ in whether there is any high-angle radiation from a horizontal radiator, and possibly in the magnitude of their "ground return losses." Appreciate your comments. 73, Chuck > > 73's > Richard Clark, KB7QHC ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 224906 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: I was going through about ten years of ham catalogs, and I noticed a disturbing trend. Date: Wed, 31 May 2006 10:39:38 -0500 Message-ID: References: $$ Steve "Morse or Re-Morse" wrote in message news:eXMdg.13$eB3.11@newsread3.news.pas.earthlink.net... > There's an increase in recent years of ham gear Retailers offering an > expanding amount of citizen band radios and related products. > > So Retailers have seen the changes in the type of people that are > making up and will be making up the US ham population, and have modified > their inventories and marketing to stay in step with it. > > Gotta keep selling them radio's, Ten-Four? > > > Morse Article: 224907 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: What happens if you pipe the output of one radio in to 2 amps? Date: Wed, 31 May 2006 16:35:04 -0500 Message-ID: References: <15322-44748CC5-24@storefull-3251.bay.webtv.net> <8X2dg.249$LO3.138@fe11.lga> <4475127b$0$1010$39cecf19@news.twtelecom.net> > news:4475127b$0$1010$39cecf19@news.twtelecom.net... > > Yuri Blanarovich wrote: > > > >> There is another potential problem if feeding two amps to two antennas > >> that are reasonably close: RF from one antenna is induced into the other > >> antenna, gets fed into the amp and causes some interference (mixing ?) > >> that shows up as a raspy signal. > >> Tried it, and heard it on another station attempting the same setup. > >> It seems that it would be easier to control the phasing at the input of > >> the PAs, but the above effect messes it up, unless antennas are widely > >> separated and they do not "feed" each other setup. > >> So, it appears that it is better to use one bigger amp and use proper > >> phasing to feed the two or more antennas. > >> I hope I did not cut incorrectly in the complex post... The effect is that the *impedance* looking into each antenna will change due to the mutual coupling of the two antennas. You can also think of it as each antenna is not just staring into open space, but you can consider the field of the other antenna to be changing the space around the first antenna (and visa versa). It is also not umlike simply putting a reflecting plane or other paracitic elements neat a driven element - the feed point impedance changes. This power, being from the same transmitter, is coherent (phase locked) and therefore changes the current that flows which manifests itself as an impedance change. Given the current from the feed line voltage and then the superposition of the current induced from the other antenna, you get a new current that flows (aparently from the feed line voltage) and therefore it appears as a different impedance (from the feed line's perspective). I hope one of these analogies works for you. This can indeed cause amplifiers to do funny things if they can't handle the resulting SWR. If you correctly match to the new impedances, there should be no problems, just the new antenna radiation pattern. Side bar: For some situations, the resistive part of this new impedance can even go negative. This means that this antenna is absorbing power, not radiating it. This can happen in phased, directive arrays used in broadcast. A friend of mine described such a situation that vexed him for a while until he improved his calculations to be more general to be applicable to this situation (to get the correct result). Don't ask me how to match to a negative resistance. All I know is that given some certain directional pattern that is desired, this happens and with the proper math you can design a matching network that works and restores order to the universe and keeps the big bang happy (:-) 73, Steve, K9DCI Article: 224908 of rec.radio.amateur.antenna From: "Cecil Moore" References: <20319-44762304-243@storefull-3258.bay.webtv.net> Subject: Re: Brainteaser Message-ID: Date: Wed, 31 May 2006 22:47:35 GMT This is a multi-part message in MIME format. ------=_NextPart_000_0009_01C684DA.4D02BD80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable "Jim Kelley" wrote: > I gotta tell ya=20 > though, it reminds me a little of one of those guys who stands out on = the street=20 > corner shaking his fist and shouting at traffic.=20 Most of us have agreed to cut out the ad hominem attacks and non- technical crappola. How about you joining us in that endeavor? What is your technical objection to what I have posted? --=20 73, Cecil http://www.qsl.net/w5dxp ------=_NextPart_000_0009_01C684DA.4D02BD80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
"Jim Kelley" <jwkelley@uci.edu>=20 wrote:
> I gotta tell ya
> though, it = reminds=20 me a little of one of  those guys who stands out on the street =
>=20 corner shaking his fist and shouting at  = traffic. 
 
Most of us have agreed to cut out the ad = hominem=20 attacks and non-
technical crappola. How about you joining us in that=20 endeavor?
 
What is your technical objection to what = I have=20 posted?
--
73, Cecil  http://www.qsl.net/w5dxp
------=_NextPart_000_0009_01C684DA.4D02BD80-- Article: 224909 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: New program. Dipole+Line+Balun+Tuner Message-ID: References: <1lmr72p1ofrs3ncickuq3da3afs5s228j9@4ax.com> Date: Thu, 01 Jun 2006 00:06:47 GMT On Wed, 31 May 2006 18:06:32 GMT, Bob Miller wrote: >For the Wireman's ladderline # 551, where would I find the line loss >at 10 mhz in db per 100 feet (and why feet, when the other parameters >are in meters?)? ~0.17dB -- Article: 224910 of rec.radio.amateur.antenna Message-ID: <447E57CA.4000105@fuse.net> Date: Wed, 31 May 2006 22:58:18 -0400 From: jawod Subject: Re: Mobile rigging References: <1149126149.855845.147040@c74g2000cwc.googlegroups.com> nm5k@wt.net wrote: > Jerseyj wrote: > >>Hi all, >>Just got a new 2006 Forrester and want to get my 2M/440 rig mounted >>along with a mag mount antenna. Someone pointed me to the "rig of the >>month" web site, but that site appears dead.. >> >>Anyone have any web sites that I can look at for information on setting >>up my radio in my car ? > > > Not to much to study...Find a good place for the radio. > Mount it. Throw the antenna on the car, and run the > coax through the best opening you can find. The only > real important thing to consider is the power source. > Don't !!! use cig lighter plugs, etc. Run fairly thick > wire directly to the battery, and fuse both the + and - > wires. If you do that, you may have to find a plug or > hole in the firewall. Most have a rubber plug of some > type. If not, you might have to drill a hole. > But at least you won't have problems with the rig > from big voltage drops due to too thin a wire, or > crusty corroded cig lighter connections/socket. > MK > Large wires, Anderson plugs are good ideas. I have a question, though. If you're running, say 10 to 15 watts to a automatic screwdriver HF antenna, can you get by with cig lighter connection? Thanks, John Article: 224911 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1149126149.855845.147040@c74g2000cwc.googlegroups.com> <447E57CA.4000105@fuse.net> Subject: Re: Mobile rigging Message-ID: Date: Thu, 01 Jun 2006 03:09:01 GMT "jawod" wrote: > I have a question, though. If you're running, say 10 to 15 watts to a > automatic screwdriver HF antenna, can you get by with cig lighter > connection? My GMC pickup has two auxiliary connections in addition to the cigarette lighter. My IC-706 runs 100W SSB just fine off of one of those aux connections. But pickups may have bigger wires than cars. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224912 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Mobile rigging Date: Wed, 31 May 2006 22:19:22 -0500 Message-ID: <127sn5qifoerc85@corp.supernews.com> References: <1149126149.855845.147040@c74g2000cwc.googlegroups.com> <447E57CA.4000105@fuse.net> jawod wrote: > nm5k@wt.net wrote: > >> Jerseyj wrote: >> >>> Hi all, >>> Just got a new 2006 Forrester and want to get my 2M/440 rig mounted >>> along with a mag mount antenna. Someone pointed me to the "rig of the >>> month" web site, but that site appears dead.. >>> >>> Anyone have any web sites that I can look at for information on setting >>> up my radio in my car ? >> >> >> >> Not to much to study...Find a good place for the radio. >> Mount it. Throw the antenna on the car, and run the >> coax through the best opening you can find. The only >> real important thing to consider is the power source. >> Don't !!! use cig lighter plugs, etc. Run fairly thick >> wire directly to the battery, and fuse both the + and - >> wires. If you do that, you may have to find a plug or >> hole in the firewall. Most have a rubber plug of some >> type. If not, you might have to drill a hole. >> But at least you won't have problems with the rig >> from big voltage drops due to too thin a wire, or >> crusty corroded cig lighter connections/socket. MK >> > Large wires, Anderson plugs are good ideas. > I have a question, though. If you're running, say 10 to 15 watts to a > automatic screwdriver HF antenna, can you get by with cig lighter > connection? > > Thanks, > > John It is still recommended that you use direct dedicated wiring to power your radio. You may be at 15 watts to day, tomorrow who knows. Dave WD9BDZ Article: 224913 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: New program. Dipole+Line+Balun+Tuner Message-ID: <8ins729020t3dadtrmriuk12tcla4qq0ig@4ax.com> References: <1lmr72p1ofrs3ncickuq3da3afs5s228j9@4ax.com> Date: Thu, 01 Jun 2006 03:29:23 GMT On Thu, 1 Jun 2006 03:04:33 +0100, "Reg Edwards" wrote: >Bob asked - >> For the Wireman's ladderline # 551, where would I find the line loss >> at 10 mhz in db per 100 feet (and why feet, when the other >parameters >> are in meters?)? > >======================================= >Bob, > >If you don't know the attenuation of your transmission line you >shouldn't be using it. > >A standard method of defining the vital attenuation parameter of a >transmission lines is "Decibels per 100 feet at some frequency or >other." It is probably stated in that form in bibles such as ARRL >publications. > >And a reputable American manufacturer will probably state it in his >sales catalogue. Or he ought to. > >Frequency is mentioned because knowing the attenuation at one >frequency allows it to be accurately calculated at any other >frequency. As is done thousands ot times in the program. > >The program asks for dB per 100 feet because, out of consideration for >USA citizens, the foot is the unit of length with which they are most >familiar. And for the rest of the World there is a statement in the >program notes that "100 feet = 30 metres." > >The alternative to asking for dB per 100 feet at 10 MHz is to provide >a look-up table which lists by name the attenuation of hundreds of >different types of transmission line used in the USA and the rest of >the World. > >Or the program could ask for conductor diameters and conductor spacing >in the case of twin lines, inner and outer diameters for coaxial >lines, also the dimensions and electrical properties of the insulating >materials. And then calculate attenuation versus frequency. > >A large number of numerical program input items would detract from a >program's usefulness. Users would soon get fed up with using it. And >the programmer would get tired of writing any more. > >Attenuation and Zo are the most important parameters of a transmission >line. To keep things simple for both program users AND the programmer >it is best that both parameters be entered directly. > >Try Google. > >The main purpose of the program is to calculate the impedance >presented to the tuner. For accuracy, line loss must be taken into >account. >---- >Reg. > Got everything plugged in -- works very nicely -- thanks... fun to change line & feedline length and see what that does at various frequencies. bob k5qwg Article: 224914 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: New program. Dipole+Line+Balun+Tuner Message-ID: References: <1lmr72p1ofrs3ncickuq3da3afs5s228j9@4ax.com> Date: Thu, 01 Jun 2006 03:49:04 GMT On Thu, 01 Jun 2006 00:06:47 GMT, Owen Duffy wrote: >On Wed, 31 May 2006 18:06:32 GMT, Bob Miller >wrote: > > >>For the Wireman's ladderline # 551, where would I find the line loss >>at 10 mhz in db per 100 feet (and why feet, when the other parameters >>are in meters?)? > >~0.17dB You didn't ask, but you need to know Zo is approx 400 ohms. -- Article: 224915 of rec.radio.amateur.antenna From: "Old Ed" References: Subject: Re: New program. Dipole+Line+Balun+Tuner Message-ID: <98ufg.514$jB5.45@newsread3.news.pas.earthlink.net> Date: Thu, 01 Jun 2006 04:35:17 GMT See below... "Reg Edwards" wrote in message news:sqSdnSTzbI07r-PZnZ2dnUVZ8qCdnZ2d@bt.com... > > "Old Ed" asked - > > > > But I am curious: What program inputs are required to > > calculate losses for tuners and baluns? Schematics? ;-) > > Coil Q? Wire type and gauge? Loss factors for ferrites? > > And how would one KNOW these parameters for real-world > > examples, say a Palstar AT-1500DT versus an Ameritron > > ATR-30? > ========================================= > > Ed, > > I've just spent half an hour thinking about how to answer your > question without having to write books on the various subjects. > > What sort of gadgets are a Palstar AT-1500AT and an Ameritron > ATR-30? Who are Palstar and Ameritron anyway? > > Manufacturers might know. Have you tried Google? > ---- > Reg. > Reg, Perhaps I assumed too much about amateur radio being a global market. Palstar is the brand name of a popular line of high-end antenna tuners (aka transmatches) that are made in the U.S.A. Ameritron is best known for their broad line of H.F. power amplifiers, but they also make a couple of antenna tuners; the ATR-30 is one. (They are now a division of MFJ; and it would be amazing if you haven't heard of MFJ.) Feel free to substitute antenna tuner models that are more familiar to you into my question, if that will make it easier to understand. I'll also try restating the question: What parameters does a user input into your newly-posted program in order to estimate tuner and/or balun losses? Predicting such losses seems inherently difficult to me; and even if the program could handle all the necessary parameters, I have a hard time seeing how one could obtain the necessary values to characterize typical commercial (or homebrew) tuners and/or baluns. Re Google, doing a search on "Palstar" leads one straight to their products, including the AT-1500 series: http://www.palstar.com/at1500cv.php Similarly, doing a Google search on Ameritron leads one straight to their products, including the ATR-30: http://www.ameritron.com/products.php?prodid=ATR-30 But I am sure that neither manufacturer has posted parameter values to use in your program--despite your well-deserved notoriety in this NG. So I am quite sure that Googling for those would be unproductive. Ed Article: 224916 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Origins of the Magnetron Date: Thu, 1 Jun 2006 00:59:04 -0500 Message-ID: <18384-447E8228-1115@storefull-3256.bay.webtv.net> References: Reg, G4FGQ wrote: "It was left to the Japanese to populate the World`s kitchens with microwave ovens." The Japanese proved adept at improving and producing high quality technical products. Japanese didn`t market the first microwave oven. Raytheon introduced its "Radar Range" soon after WW-2 ended. Japanese copies were innovative, reliable, and cheap, so they won instant acceptance worldwide. The magnetron has been called the best import ever from Britain and I think that comparison even included Bob Hope and Liz Taylor. At the time of the magnetron gift to the U.S., British war production was already bursting at the seams and the U.S. was well advanced in radar and had a few tricks up its sleeve to improve the British gear. I`ve noticed early British airborne radar using yagi antennas. That seemed quaint to me. Best regards, Richard Harrison, KB5WZI Article: 224917 of rec.radio.amateur.antenna From: =?utf-8?b?Sm9uIEvDpXJlIEhlbGxhbg==?= Subject: Re: RF grounding methods for sailboats: A Summary Date: 01 Jun 2006 10:32:51 +0200 Message-ID: <1m1wu9qnrg.fsf@persaunet.uninett.no> References: <1148994725_36063@sp6iad.superfeed.net> <1mbqter0t0.fsf@persaunet.uninett.no> <1149082403_44817@sp6iad.superfeed.net> chuck writes: > Jon Kåre Hellan wrote: > We don't seem to have widely used, descriptive names for these > configurations. Cecil is correct, and perhaps the OCF referred to > should be called an OCF "L". The vertical radiator with a single, > elevated, horizontal, resonant "radial" perhaps should be called an > "L" dipole. > > On inspection, either antenna, on a boat with a tuner at the > feedpoint, could be mistaken for the other. You could tell the > difference only by observing how the antenna is operated. If the > antenna is operated only on those frequencies for which the horizontal > element is an odd multiple of a 1/4 wavelength, we would call the > antenna an "L" dipole (or whatever). > > If that same antenna were operated not only on those frequencies, but > on all others (HF spectrum) as well, we would call it an OCF "L". > > But if, on inspection, the antenna has multiple resonant radials, that > would unambiguously differentiate it from the OCF. > > Whenever the two antennas are physically identical, they will > obviously operate identically. > > Make sense, Jon? Sorry for the confusion. Sure. Thanks. Article: 224918 of rec.radio.amateur.antenna Date: Thu, 01 Jun 2006 20:50:41 +1000 From: bob Subject: Re: RF grounding methods for sailboats: A Summary References: <1148994725_36063@sp6iad.superfeed.net> <6ggr72509n8k0ulii7a3j574e6ogiuhrbp@4ax.com> <1149107678_2377@sp6iad.superfeed.net> Message-ID: <447ec69c_1@news.iprimus.com.au> chuck wrote: > Richard Clark wrote: >> On Tue, 30 May 2006 09:21:56 -0400, chuck wrote: >> >>> If anyone spots any errors of fact or significant omissions, I'd >>> welcome appropriate "recalibration". Thanks in advance. >>> >>> 1) Grounding plates >>> >>> Will not work if submerged as much as four feet >> >> Hi Chuck, >> > > > Hello Richard, > > Perhaps the context for the summary was unclear. My objective was simply > to identify several existing recommendations for obtaining RF grounds on > plastic and wood vessels over saltwater. Regrettably, I lack knowledge > of any published theoretical or empirical comparison of these proposals > that provides an objective, quantifiable measure of performance. > >> Don't know how you got this miss-impression. >> > > That it will not work if submerged as much as four feet? From Roy's > report on his NEC-4 modeling. It is presumably based on the known skin > depth of RF at 14 MHz. > >>> 2) Wire in water >>> >>> A one-foot length of wire immersed near water surface is sufficient for >>> near-perfect results based on W7EL's NEC-4 model results. Assumed >>> performance is similar to grounding plate. >> >> This conclusion is conflict with the first, making it a mystery how >> you came to either in summary. The focus on "water surface" is as >> though you are trying to force it work like a pool of mercury. Water >> is NOT a ground plane in the sense of conductivity. Water is a >> terrible conductor. It is only its huge mismatch with air that gives >> it such superb propagation, not match, characteristics. Distinguish >> between the two. >> > > Well, some of what you are saying is pretty much what I had thought. If > you read my posts on the other thread, you'll see where I was heading. > > We agree that seawater's conductivity is lower than copper's but greater > than earth's. We agree that a single ground rod driven into the earth > will perform poorly as the only return path for a vertical antenna over > land, but at least in some cases will perform better than if it were not > there. Will a wire dipped into the sea perform better than the ground > rod driven into the earth? I doubt there is much disagreement on that, > even though water might be characterized in relative terms as a > "terrible conductor". The only relevant question, then, is "how much > better?" and so far, the only numerical answer that I am aware of has > come from NEC modeling. > > The characterization I reported of a wire dipped into the sea is based > on Roy's modeling, assuming I have not misunderstood of course. Others > have made the same point, but now we have model results to support it. > > BTW, I have just discovered a response from Roy to one of my posts on > the other thread that is available on Google, but has never shown up on > either of the two newsgroup subscriptions I have. Roy addressed some of > my concerns in that post so if you have not seen it you might do a > search for it on Google. > > >>> 3) Radials >>> >>> Even shortened (loaded) radials elevated over seawater work as >>> near-perfect based on N6LF's NEC-4 modeling. Objections to radials are >> >> The objections are they are wholly unnecessary when ground is so >> easily achieved by conventional means. You would need 120 radials to >> shield against the loss you perceive, and that loss doesn't matter > > What loss is it that I perceive? N6LF's results show near lossless > results with only four shortened radials over seawater. > >> when you stand to gain so much in propagation. You couldn't even >> field a tenth of these radials. At HF, and maintaining their tune >> and symmetry, you would be lucky to fit in 2. > > Other studies have shown a single elevated radial over land to lose less > than one dB over a perfect ground plane. > > At that stage of the >> game, there is absolutely no match advantage over conventional >> techniques aboard a small craft (and at HF you don't qualify for any >> thing other). > >>> 4) Counterpoise (i.e., mast, forestay, shrouds, lifelines, engine, metal >>> tanks, 100 square feet of copper, keel, rudder, etc. bonded together) >>> >>> This type of >>> counterpoise is also the approach recommended by both Icom and SGC. >> >> Only because it is already available and doesn't ask you to go any >> further for no obvious advantage. >> > > Well, what makes life interesting is that to advocates of the other > approaches, there are obvious advantages. > >>> 5) OCF dipole w/horizontal component along deck >>> >>> Not commonly used, >> >> Who would choose a complicated design over so many simple ones? >> > > Multiple resonant radials that cover the popular marine and ham bands on > a small boat are not seen by all as simple. One might ask the same > question of those who advocate the counterpoise approach, since the wire > in the water is simpler. I think choosing the best system (broadly > defined to also consider operation over fresh water and near-vertical > radiation when important) will be easy if we can only get some > objective, reproducible data and/or analysis. > > >>> Is that where it stands, folks? >> >> If you want a dipole, make a VERTICAL dipole, even a lousy one. >> > > Certainly worthy of consideration. Many backstay antennas are probably > operated as half-wave vertical dipoles (end-fed, of course) above 10 MHz > or so. > >> Finally, and to repeat, learn the distinction between matching and >> propagation. Your focus on matching issues is like seeing your glass >> 3/4ths empty. Looking at the propagation advantages in comparison is >> like seeing a pitcher of water nearby that will fill that glass a >> dozen times. > > I didn't address any matching issues at all that I can see, Richard. > Sorry if I misled you. > > All of the alternatives utilize the same seawater for propagation and > the same vertical radiator. They differ in whether there is any > high-angle radiation from a horizontal radiator, and possibly in the > magnitude of their "ground return losses." > > > Appreciate your comments. > > 73, > > Chuck > >> >> 73's >> Richard Clark, KB7QHC > > ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet > News==---- > http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ > Newsgroups > ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- I would also add that sea waters conductivity is not a consistent as some seem to think. The salinity of salt water varies with temperature. NASA has surveyed most of the world oceans using microwave radar and salinity if far from consistent. This fact combined with tidal flows, man made pollution from storm water drains and other factors makes "connecting" to sea water seem dubious. If we assume you can connect to sea water, do you want to place most of your current in such a small area? I doubt someone could keep this connection clean enough in seawater to be efficient. This fact combined with electrolysis will lay waste to any connection very quickly. Maybe a gold plated conductor might be able to survive in a salt water environment. The way most people install radials in yacht would make them elevated, rather than buried below skin depth. N6LF has indicated in his modeling that short radials as long as .1 wavelength work just as effectively as 0.5 wavelength radials over sea water. Since you not trying to combat ground loss whats the point of trying to build a radial field when 2 or 4 .1 wavelength radials will do the job? Besides building a elevated radial system will have some capacitance to ground. A single radial should over sea water capture most of not all of the antenna return currents Besides from all the posts i have read burying something like a Dynaplate below skin depths is akin to burying your rf current below a copper plate. I also believe there is a rule of thumb that 5 skins depths is the maximum return on investment in using the available conductive depth of any material. Its probably that its only ever the piece of wire to the dynaplate thats working as a short radial. I dont see how anyone can say a dynaplate could ever work when below skin depth? One thing i am curious about is that if you suspend a radiator or conductor well below skin depth in air whats the radiation efficiency like of that conductor? To me on a yacht it looks like a conductor suspended in a U channel suspended in air with the top open and exposed. Maybe it will operate like a waveguide with some cut off frequency, this is a wild guess.Maybe someone who can model conductors below ground can model this. Most yachts have at least 3ft of freeboard above water to play with. But who knows there seems to conflicting advice on several points. Maybe Roy can clarify all these issues with his models. Bob Article: 224919 of rec.radio.amateur.antenna From: Buck Subject: Re: Mobile rigging Message-ID: References: <1149126149.855845.147040@c74g2000cwc.googlegroups.com> <447E57CA.4000105@fuse.net> Date: Thu, 01 Jun 2006 07:36:13 -0400 >Large wires, Anderson plugs are good ideas. >I have a question, though. If you're running, say 10 to 15 watts to a >automatic screwdriver HF antenna, can you get by with cig lighter >connection? > >Thanks, > >John Many years ago, I used a 35 watt transceiver on a cigarette lighter plug. Someone told me I was making a mistake. We measured the output of the rig, connected it direct and measured it again. The output of the rig was a few watts lower on the plug as opposed to direct wiring. It wasn't significant enough to be detected on the air, but it proved the inefficiency of using the cigarette lighter for a source of power. I now use #8 wire directly to the battery for all my mobile amateur radio wiring. I never tried to determine if it was the plug itself, or the wiring that caused the power drop, but I found a website that allows you to calculate the voltage drop of wire given the length, wire size and current. -- 73 for now Buck N4PGW Article: 224920 of rec.radio.amateur.antenna From: szekeres@pitt.edu (GregS) Subject: Re: I was going through about ten years of ham catalogs, and I noticed a disturbing trend. Date: Thu, 01 Jun 2006 13:02:07 GMT Message-ID: References: In article , "Steve N." wrote: > $$ > >Steve > >"Morse or Re-Morse" wrote in message >news:eXMdg.13$eB3.11@newsread3.news.pas.earthlink.net... >> There's an increase in recent years of ham gear Retailers offering an >> expanding amount of citizen band radios and related products. >> >> So Retailers have seen the changes in the type of people that are >> making up and will be making up the US ham population, and have modified >> their inventories and marketing to stay in step with it. >> >> Gotta keep selling them radio's, Ten-Four? Well years back there were CB STORES everywhere, and places like Sears and Wards sold CB's, not anymore. Someone has to sell them. Very litle interest in CB these days, however its the only real way to try and communicate with other drivers on the road. greg Article: 224921 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: New program. Dipole+Line+Balun+Tuner Message-ID: <0upt725i7osph0v3gherio78gug3sdh8fo@4ax.com> References: <1lmr72p1ofrs3ncickuq3da3afs5s228j9@4ax.com> Date: Thu, 01 Jun 2006 13:13:05 GMT On Thu, 01 Jun 2006 03:49:04 GMT, Owen Duffy wrote: >On Thu, 01 Jun 2006 00:06:47 GMT, Owen Duffy wrote: > >>On Wed, 31 May 2006 18:06:32 GMT, Bob Miller >>wrote: >> >> >>>For the Wireman's ladderline # 551, where would I find the line loss >>>at 10 mhz in db per 100 feet (and why feet, when the other parameters >>>are in meters?)? >> >>~0.17dB > >You didn't ask, but you need to know Zo is approx 400 ohms. Thanks for the info -- I entered 390 ohms. bob k5qwg Article: 224922 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: What happens if you pipe the output of one radio in to 2 amps? Date: Thu, 01 Jun 2006 07:02:14 -0700 Message-ID: <127tsratj3vl886@corp.supernews.com> References: <15322-44748CC5-24@storefull-3251.bay.webtv.net> <8X2dg.249$LO3.138@fe11.lga> <4475127b$0$1010$39cecf19@news.twtelecom.net> Steve N. wrote: > . . . > Side bar: > For some situations, the resistive part of this new impedance can even go > negative. This means that this antenna is absorbing power, not radiating > it. This can happen in phased, directive arrays used in broadcast. A > friend of mine described such a situation that vexed him for a while until > he improved his calculations to be more general to be applicable to this > situation (to get the correct result). > Don't ask me how to match to a negative resistance. All I know is that > given some certain directional pattern that is desired, this happens and > with the proper math you can design a matching network that works and > restores order to the universe and keeps the big bang happy (:-) Negative feedpoint resistances in phased arrays have of course been known for a very long time. One of the example files (4Square.EZ) which comes with EZNEC shows an element with a slightly negative feedpoint resistance. The accompanying "antenna notes" file includes a brief explanation of the phenomenon. You can't "match to" a negative resistance, because matching requirements are determined by the load, not source, impedance, and an element with a negative resistance is a source rather than a load. But there's no necessity to match individual elements and, in fact, attempting to do so complicates the problem of achieving the desired element current ratios. One thing you can count on, though -- the resistance of the whole array will be positive. And that's what needs matching. Roy Lewallen, W7EL Article: 224923 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <15322-44748CC5-24@storefull-3251.bay.webtv.net> <8X2dg.249$LO3.138@fe11.lga> <4475127b$0$1010$39cecf19@news.twtelecom.net> Subject: Re: What happens if you pipe the output of one radio in to 2 amps? Message-ID: Date: Thu, 1 Jun 2006 10:31:56 -0400 "Steve N." wrote in message news:e5l269$ufp$1@avnika.corp.mot.com... >> news:4475127b$0$1010$39cecf19@news.twtelecom.net... >> > Yuri Blanarovich wrote: >> > >> >> There is another potential problem if feeding two amps to two antennas >> >> that are reasonably close: RF from one antenna is induced into the > other >> >> antenna, gets fed into the amp and causes some interference (mixing ?) >> >> that shows up as a raspy signal. >> >> Tried it, and heard it on another station attempting the same setup. >> >> It seems that it would be easier to control the phasing at the input >> >> of >> >> the PAs, but the above effect messes it up, unless antennas are widely >> >> separated and they do not "feed" each other setup. >> >> So, it appears that it is better to use one bigger amp and use proper >> >> phasing to feed the two or more antennas. >> >> > > I hope I did not cut incorrectly in the complex post... > > The effect is that the *impedance* looking into each antenna will change > due > to the mutual coupling of the two antennas. You can also think of it as > each antenna is not just staring into open space, but you can consider the > field of the other antenna to be changing the space around the first > antenna > (and visa versa). It is also not umlike simply putting a reflecting plane > or > other paracitic elements neat a driven element - the feed point impedance > changes. This power, being from the same transmitter, is coherent (phase > locked) and therefore changes the current that flows which manifests > itself > as an impedance change. Given the current from the feed line voltage and > then the superposition of the current induced from the other antenna, you > get a new current that flows (aparently from the feed line voltage) and > therefore it appears as a different impedance (from the feed line's > perspective). I hope one of these analogies works for you. > This can indeed cause amplifiers to do funny things if they can't handle > the > resulting SWR. If you correctly match to the new impedances, there should > be no problems, just the new antenna radiation pattern. > That could be a challenging task, if one wanted to have switchable or tunable phasing. Some fancy detection and adjustments needed!? > Side bar: > For some situations, the resistive part of this new impedance can even go > negative. This means that this antenna is absorbing power, not radiating > it. This can happen in phased, directive arrays used in broadcast. A > friend of mine described such a situation that vexed him for a while until > he improved his calculations to be more general to be applicable to this > situation (to get the correct result). > Don't ask me how to match to a negative resistance. All I know is that > given some certain directional pattern that is desired, this happens and > with the proper math you can design a matching network that works and > restores order to the universe and keeps the big bang happy (:-) > > 73, Steve, K9DCI > Hi Steve, That makes sense (and subject for scientwists to argue "it can't be" :-) I was considering two scenarios for contesting. One, mainly for expeditioning case, use two smaller amps (transportation limitations) and low power (continuous) phasing network between the exciter and two amps feeding two antennas. Two, feeding two amps and two antenna systems firing in different directions (offset stacks). I tried the crude application of it, and was "bugged" that my CW tone or SSB modulation was raspy. I knew that rig was OK, firing one leg was no problem and had to conclude that the problem had to be mutual coupling, feedback and "beating" back in the amp circuits. I did not pursue the rectification of the problem, considered it too complicated for what I wanted to do. Learned it to be a no-no trying to feed phased arrays with individual amplifiers, at the same frequency. Feeding antennas that are widely separated with no mutual coupling, firing in different directions, should not be a problem, as long as there is no significant signal being induced into the other system. We will play with some outrageous combinations of about 40 rhombics and other antennas, capable of being fed by 16 transmitters from the new Tesla RC QTH of old AT&T Ocean Gate NJ site (makes old W6AM site look like kindergarten :-). Antenna matrix (wall unit) switch that does the selection is a piece of art in itself. We have to get rid of pigeons and "paintings" they left and get the site operational by the fall contest season. -- 73, Yuri Blanarovich, K3BU, VE3BMV Article: 224924 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: RF grounding methods for sailboats: A Summary Date: Thu, 1 Jun 2006 10:45:19 -0500 Message-ID: <16029-447F0B8F-218@storefull-3254.bay.webtv.net> References: Reg, G4FGQ wrote: "Anything you toss into the sea water makes a good ground." Certainly correct if "anything" is a low-impedance RF path. If "skin effect" prevents penetration to a copper plate on the hull, fine. RF has then made the transfer to the sea at a shallow depth. That`s the goal. Best regards, Richard Harrison, KB5WZI Article: 224925 of rec.radio.amateur.antenna Subject: Re: Mobile rigging From: Ed Date: 01 Jun 2006 17:01:18 GMT Message-ID: References: <1149126149.855845.147040@c74g2000cwc.googlegroups.com> <447E57CA.4000105@fuse.net> > > > I never tried to determine if it was the plug itself, or the wiring > that caused the power drop, but I found a website that allows you to > calculate the voltage drop of wire given the length, wire size and > current. > > 35 years experience tells me that biggest issue regarding voltage drop in most wiring harnesses is the connections, not the wire itself. Unsoldered metal to metal connections, especially crimp type, are especially problematic. Ed K7AAT Article: 224926 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: What happens if you pipe the output of one radio in to 2 amps? Date: Thu, 1 Jun 2006 12:09:05 -0500 Message-ID: <16028-447F1F31-995@storefull-3254.bay.webtv.net> References: Yuri, K3BU wrote: "Learned it to be a no-no trying to feed phased arrays with individual amplifiers, at the same frequency." I`m not sure separate amplifiers have anything to do with distortion because I`ve seen distortion at certain azimuths from arrays driven by a single amplifier. Drive around a broadcast array with sharp nulls while listening. You will notice severe distortion at the edges of sharp nulls. I always attributed this to phase out of the carrier frequency at an azumuth where the sidebands aren`t completely nulled out, and this produces the overmodulation and distortion. It`s only a speculation to explain the cause of an observed effect. Best regards, Richard Harrison, KB5WZI Article: 224927 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: What happens if you pipe the output of one radio in to 2 amps? Date: Thu, 1 Jun 2006 13:07:53 -0500 Message-ID: References: <15322-44748CC5-24@storefull-3251.bay.webtv.net> <8X2dg.249$LO3.138@fe11.lga> <4475127b$0$1010$39cecf19@news.twtelecom.net> <127tsratj3vl886@corp.supernews.com> "Roy Lewallen" wrote in message news:127tsratj3vl886@corp.supernews.com... > Steve N. wrote: > > . . . > > Side bar: > > For some situations, the resistive part of this new impedance can even go > > negative. ... > > Negative feedpoint resistances in phased arrays have of course been > known for a very long time. Roy, I didn't mean to imply it wasn't known previously, only wanted to give a real life example (as a preemptive attempt at heading off a potential "but that's all theory" response -- perhaps a little gun-shy on this news group (:-)). I also have no direct knowledge of this type of the network design, but it has to be designed and the antenna with the neg real part is part of the system that gets hooked to the network. > You can't "match to" a negative resistance, because matching > requirements are determined by the load, not source, impedance, OOPS ! I *know* what you mean, but it takes knowledte of both ends - We, me included, can eaily forget that we have an arbitrarily defined (50 ohm) system that we easily take for granted. ya gotta know you're in a 50 ohm (or whatever) system to "do" the match. 73, Steve, K9DCI Article: 224928 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: What happens if you pipe the output of one radio in to 2 amps? Date: Thu, 1 Jun 2006 13:09:39 -0500 Message-ID: References: <15322-44748CC5-24@storefull-3251.bay.webtv.net> <8X2dg.249$LO3.138@fe11.lga> <4475127b$0$1010$39cecf19@news.twtelecom.net> <44764307$0$1016$39cecf19@news.twtelecom.net> <4476ef4e$0$1013$39cecf19@news.twtelecom.net> <1148646180.019541.169980@u72g2000cwu.googlegroups.com> <1148654506.771091.181630@g10g2000cwb.googlegroups. <4oadnezMd691terZnZ2dnUVZ8s2dnZ2d@bt.com> "Reg Edwards" wrote in message news:4oadnezMd691terZnZ2dnUVZ8s2dnZ2d@bt.com... > > > I'm gonna be like Brer Rabbit and say nuffin. > But you just did! sorry, couldn't resist. I wasn't gonna say anything, until I just thought of that: 73, Steve, K9DCI Article: 224929 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: Grounding a metal roof Date: Thu, 1 Jun 2006 13:27:40 -0500 Message-ID: References: <1148272981_5573@sp6iad.superfeed.net> And so it goes... "Sal M. Onella" wrote in message news:lkQdg.27874$QP4.7530@fed1read12... > > "Steve N." wrote in message > news:e57vbg$ehk$1@avnika.corp.mot.com... > Snip > > The radiation will therefore mimic that noise > > also. ... > > Correct John, Thanks. > ... > ...(command = FTSCPAC, if you know that outfit) ... No. I have successfully blotted all that stuff out of my mind, but, then, I was a short-timer from day one. Perhaps I do remember something like CNCPACFLT (sync - pack - fleet)... I was in the Phillipines, uh oh! it's comming back ... NAV COM STA PHIL > I/we demonstrated with two links of chain, connected back-to back to make a > continuous current path, that we could generate noise by making and breaking > the connection where the links touched. It was invariably a convincing demo > for the students. The effect only extended out a few inches from the deck > of our plywood model, but scale it up, and you are smack-dab in the real > world. Totally cool demo. I first became aware of it when I had litterally a garage repair shop, after the Navy. I had a Motorola monitor receiver that sat on one common frequency and was used to measure deviation on 2M radios in the late 60's/70's. If I keyed a transmitter on another frequency and happened to scrape a screwdriver on another condusting surface, I'd hear noise in the monitor. I therefore dubbed it the "screwdriver effect". Later, at Motorola, I had to track down some receiver desense in a car phone and traced it to pickup of the Caddy trunk-closing motor wiring, somehow bringing RF into what appeared to be the dash and possibly a lousy oscillator for some unknown equipment, that, was re-radiated causing Rx noise. I also had to look for some "motion induced desense" and found bumber mounts and also motorcycle seat springs to be responsible. I had to develop a detection system and used one of the FM receivers with a weak, slightly off ferquency signal injected in parallel with a small loop to sniff the offending junctions while someone bounsed on the suspect body part ... At that time, that's when I ran across rthe paper describing the HF interference via the deck chains to the radars on NASA ships. We dubbed this effect "Environmental Desense". There is a 2M repearer in NE Illinois that has this quite often when there is wind. 73, Steve, K9DCI Article: 224930 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: Grounding a metal roof Date: Thu, 1 Jun 2006 13:34:55 -0500 Message-ID: References: <1148272981_5573@sp6iad.superfeed.net> <4477db49.5273685@bart.spawar.mil> "Sal M. Onella" wrote in message news:F5aeg.27941$QP4.12044@fed1read12... > > "Bart Bailey" wrote in message > news:4477db49.5273685@bart.spawar.mil... > > In Message-ID: posted on Fri, 26 May > > 2006 21:12:01 -0700, Sal M. Onella wrote: > > > > > ... > they used brass ship models, Ahhh! the days before Roy and his "modeling software" when we used "modeling hardware" (:-) When ships were made of wood and men were made of steel. [[you could tell by the 'rust' stains on their skivvies]] sorry, still a little old salt left in the veins... It's amazing what you can do when money is no object... 73, Steve, K9DCI Article: 224931 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: seperation in lie of a duplexer at 222 mhz band Date: Thu, 1 Jun 2006 14:02:03 -0500 Message-ID: References: <1148246239.775059.271390@u72g2000cwu.googlegroups.com> <1271pgcl22ihl42@corp.supernews.com> Dave has some good info too, but here's some background. Transmitters ALL have noise coming out that decreases as you move away from the carrier. We call this sideband noise. This noise can cover up your received signal if it is high enough (which is not difficult) on the receive frequency. A duplexer or cavity set can (if needed) have a notch at the _RX_ frequency to reduce this noise. Cavities like this are called "pass-reject" cavities because they have a band-pass characteristic for the transmitter frequency and a notch which can also be tuned to the receiver frequency to reduce this noise more than the simple cavity skirts can. Transmitters can have spurs and if you have that, you have a similar problem because it is just a single frequency which could cover a received signal and you must reduce. However, chances of having a spur on your receiver frequency is rare (though synthesizers can cause quite a few near the carrier, so you want to stay away from a synthesized radio if possible, for a repeater, for that reason) While we talk of "receiver overload, blocking, desense" receivers have one characteristic which is not obvious to most. Since ALL oscillators have this sideband noise mentioned above, the local oscillator IN the receiver also has some. When a strong carrier enters the receiver (your own transmitter), _it_ becomes another local oscillator in the mixer and can mix with the sideband noise of the intentional LO. This mixes some part of the sideband noise of the LO onto the desired frequency. This is one of the mechanisims for receiver desense and one reason to reduce the amount of TX power getting to the receiver. With synthesixed receivers, it CAN be the dominant cause for desense. This is because the VCOs needed for synthesizers typically can have quite high sideband noise. Since a typical radio is not designed for repeater operation, it's design will not try to optimize for sideband noise. On 2M you can probably hear this effect with just about any two 2M ham rigs. Talk to someone on the local repeater, but not too close to the repeater (I'd say at least 5 miles away) and drive close to each other. At some point he repeater will get noisy and if you have a good ear, you can hear that this noise is different than the normal, weak signal noise. When the other station de-keys, the repeater will quiet with it's normal gusto. 73, Steve, K9DCI Article: 224932 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: FIGHT! FIGHT! FIGHT! Date: Thu, 1 Jun 2006 14:17:39 -0500 Message-ID: References: <17757-44746714-21@storefull-3257.bay.webtv.net> <1148486661.748365.219740@u72g2000cwu.googlegroups.com> wrote in message news:1148486661.748365.219740@u72g2000cwu.googlegroups.com... > ...> By the way, generating new frequencies is not necessarily a violation > of superposition (though it usually is). Consider a system undergoing > a constant Doppler shift. > > 73, > Glenn AC7ZN > Glenn, boy! I can't read all these posts, so I was trying to see where you were going and asking by just skimming, primarily your posts. The above caught my eye. Doppler is not "generating new frequencies" as a non linearity does. A non-linear system will produce harmonics with one exitation frequency and produce the common mixing / IM with multiple exitation (superimposed) frequencies. I think trying to mix relativistic effects in with the stationary world is an unnecessary complication of a linearity discussion. If I have time I'll try to follow the thread to see what you're really after...but. If it takes mega watts to see some non linearity in an antenna, who cares? and more importantly how will you know whree it is occuring since things like the junction of two connectorc can produce enough IM to mask other, smaller sources. If you tried an experiment looking for IM / Mixing you might try to use a receiver becaue a receiver could be a very sensitive detector...but you'd have to have a pretty good receiver. Something like a kW LO and mixer to have a really good intercept. I'm not sure of the point here... Do antennas cause IM? Sounds like a deadend arena to me. 73, Steve, K9DCI Article: 224933 of rec.radio.amateur.antenna From: Bruce in Alaska Subject: Re: RF grounding methods for sailboats: A Summary References: <1148994725_36063@sp6iad.superfeed.net> <6ggr72509n8k0ulii7a3j574e6ogiuhrbp@4ax.com> <1149107678_2377@sp6iad.superfeed.net> <7k3s725tjkumuqplvjslhb7vr0ei4o292g@4ax.com> Message-ID: Date: Thu, 01 Jun 2006 19:55:39 GMT In article <7k3s725tjkumuqplvjslhb7vr0ei4o292g@4ax.com>, Richard Clark wrote: > If they all utilize the same seawater for propagation and the same > vertical radiator, they all suffer equally - it stands to reason there > is no difference given all the "sameness." It also stands to reason > by your assertion that they differ, that they do not all use the same > seawater or vertical.... Which is it? Let's skip that and cut to the > heart of the matter. How MUCH different? > > Start with a conventional untuned vertical using a dynaplate and tell > me, in dB, how much better any other scheme is. Let's confine this to > a practical situation where the rig is under cover and inside the boat > and that you need two leads, one from the tuner antenna connection, > and another from the tuner ground connection. > > 73's > Richard Clark, KB7QHC This is exactly right. If they all use the same water for RF Ground, and vertical, for the antenna, then the only difference is, "How much coupling from the ground stud on the antenna tuner does each system give to the water?" And that is the Thousdan Dollar question. DynaPlate, Bonded RF Ground System, wires, radials, whatever, all, just make up one side of the capacitor, with the water as the otherside and the distance between is the dielectric. More effective coupling equals lower impedance RF Ground. All this talk of Modelling is just so much FuFurrR, for anyone who has installed MF/HF Marine Antenna Systems on these type, wood or plastic vessels. Anyone with much experience in the field will tell you, simply, get as much surface area as possible, bonded with low impedance connections, (Copper Strap) and get it as close to the water as possible. The Physics of building a bigger capacitor is: Have as much surface area as possible, with the least space between the plates. This isn't Rocket Science, it is just basic physics, and all the crap about tuned counterpoises, and copper screens in the overhead, and the like is just that...... crap...woun't work, never has, and never will. It doesn't take a NEC Modelling Software Package to figure this out, it just takes some common sense and a bit of OJT Experience.... Bruce in alaska -- add a <2> before @ Article: 224934 of rec.radio.amateur.antenna From: You Subject: Re: RF grounding methods for sailboats: A Summary References: <16029-447F0B8F-218@storefull-3254.bay.webtv.net> Message-ID: Date: Thu, 01 Jun 2006 20:00:03 GMT In article <16029-447F0B8F-218@storefull-3254.bay.webtv.net>, richardharrison@webtv.net (Richard Harrison) wrote: > If "skin effect" prevents penetration to a copper plate on the hull, > fine. RF has then made the transfer to the sea at a shallow depth. > That`s the goal. Bullshit, where do you guys come up with this stuff....Skin Effect is a a Boundry Thing, and the hull of the vessel is the "Boundry of the Sea Water" even if it is 10 feet below the sea surface. Article: 224935 of rec.radio.amateur.antenna Subject: Re: I was going through about ten years of ham catalogs, and I noticed a disturbing trend. From: "Morse or Re-Morse" References: Message-ID: Date: Thu, 01 Jun 2006 23:44:21 GMT szekeres@pitt.edu (GregS) wrote in news:e5mogu$huo$4@usenet01.srv.cis.pitt.edu: > In article , "Steve N." > wrote: >> $$ >> >>Steve >> >>"Morse or Re-Morse" wrote in message >>news:eXMdg.13$eB3.11@newsread3.news.pas.earthlink.net... >>> There's an increase in recent years of ham gear Retailers offering an >>> expanding amount of citizen band radios and related products. >>> >>> So Retailers have seen the changes in the type of people that are >>> making up and will be making up the US ham population, and have >>> modified their inventories and marketing to stay in step with it. >>> >>> Gotta keep selling them radio's, Ten-Four? > > Well years back there were CB STORES everywhere, and places like Sears > and Wards sold CB's, not anymore. Someone has to sell them. Radio Shack. You got questions, we got blank stares. Morse Article: 224936 of rec.radio.amateur.antenna Date: Thu, 01 Jun 2006 21:19:00 -0500 From: Tom Ring Subject: Re: What happens if you pipe the output of one radio in to 2 amps? References: <16028-447F1F31-995@storefull-3254.bay.webtv.net> Message-ID: <447fa014$0$6142$39cecf19@news.twtelecom.net> Richard Harrison wrote: > Yuri, K3BU wrote: > "Learned it to be a no-no trying to feed phased arrays with individual > amplifiers, at the same frequency." > > I`m not sure separate amplifiers have anything to do with distortion > because I`ve seen distortion at certain azimuths from arrays driven by > a single amplifier. > > Drive around a broadcast array with sharp nulls while listening. You > will notice severe distortion at the edges of sharp nulls. I always > attributed this to phase out of the carrier frequency at an azumuth > where the sidebands aren`t completely nulled out, and this produces the > overmodulation and distortion. It`s only a speculation to explain the > cause of an observed effect. > > Best regards, Richard Harrison, KB5WZI > I wonder if we can really define that as distortion. It's distortion to you at the time perhaps, since the whole signal as you'd like it to be delivered is not there while you drive through the null. However, the antenna system is just doing its job, and doing it well in the directions it was intended. The nulls are by nature not supposed to contain signals with smooth frequency response, since they aren't supposed to contain any signal at all if perfect, correct? tom K0TAR Article: 224937 of rec.radio.amateur.antenna From: Buck Subject: Re: Mobile rigging Message-ID: References: <1149126149.855845.147040@c74g2000cwc.googlegroups.com> <447E57CA.4000105@fuse.net> Date: Thu, 01 Jun 2006 23:25:46 -0400 On 01 Jun 2006 17:01:18 GMT, Ed wrote: > > >> >> >> I never tried to determine if it was the plug itself, or the wiring >> that caused the power drop, but I found a website that allows you to >> calculate the voltage drop of wire given the length, wire size and >> current. >> >> > > 35 years experience tells me that biggest issue regarding voltage drop >in most wiring harnesses is the connections, not the wire itself. >Unsoldered metal to metal connections, especially crimp type, are >especially problematic. > > > Ed K7AAT That may well be. However, I still use the wire with the least voltage drop I can reasonably afford. (#8 was available, flexible, and relatively inexpensive for the length I needed, #00 was too stiff and large to manipulate in my car. :) -- 73 for now Buck N4PGW Article: 224938 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <16028-447F1F31-995@storefull-3254.bay.webtv.net> Subject: Re: What happens if you pipe the output of one radio in to 2 amps? Message-ID: Date: Fri, 2 Jun 2006 00:08:31 -0400 "Richard Harrison" wrote in message news:16028-447F1F31-995@storefull-3254.bay.webtv.net... > Yuri, K3BU wrote: > "Learned it to be a no-no trying to feed phased arrays with individual > amplifiers, at the same frequency." > > I`m not sure separate amplifiers have anything to do with distortion > because I`ve seen distortion at certain azimuths from arrays driven by > a single amplifier. > > Drive around a broadcast array with sharp nulls while listening. You > will notice severe distortion at the edges of sharp nulls. I always > attributed this to phase out of the carrier frequency at an azumuth > where the sidebands aren`t completely nulled out, and this produces the > overmodulation and distortion. It`s only a speculation to explain the > cause of an observed effect. > > Best regards, Richard Harrison, KB5WZI > The effect, distortion, seemed to be noticeable in any or all directions and over DX path. The only thing we could figure out, was that it had to do with separate amps feeding separate ants. Switching to either one, signals were clean. Feeding two antennas from one exciter through hybrid was no problem. In my case it was 4 square and Inv Vee about 3/8 wave away. I have heard the same effect on one YU station, and he was getting reports of raspy signal and when I told him to turn the other amp off, he was clean. The distortion was quite significant, it produced complaints from about one in five stations worked. Closest thing to describe it, would like signals distorted by Aurora. 73 Yuri, K3BU Article: 224939 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <18384-447E8228-1115@storefull-3256.bay.webtv.net> Subject: Re: Origins of the Magnetron Message-ID: <6nPfg.28256$QP4.810@fed1read12> Date: Thu, 1 Jun 2006 21:44:49 -0700 "Ian White GM3SEK" wrote in message news:kmieVPE+IpfEFA1P@ifwtech.co.uk... > Those were the phased arrays for the earlier VHF radar, and consisted of > two or four two-element yagis clustered around the nose (of a > two-engined aircraft, obviously). This gave a fairly good > forward-looking capability. Both sides did much the same, and given the > relatively long wavelength, it's hard to think how better to do it. > > The huge benefit of the magnetron was that it operated at much shorter > wavelengths, which frees up the antenna design and provides much better > spatial resolution - witness the downward-looking "H2S" radar which was > the magnetron's first major deployment. The VHF radars were still around into the late 1970's, maybe beyond. The US Navy had them on carriers for air search. I think the nomenclature was AN/SPS-29 and/or AN/SPS-37. The one I recall was in the 218 - 220 MHz and it was hell on TV channel 13! The antenna was referred to as a bedspring array; the rectangular framework for the dipole radiating elements resembled a giant bedspring. Article: 224940 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1148272981_5573@sp6iad.superfeed.net> Subject: Re: Grounding a metal roof Message-ID: Date: Thu, 1 Jun 2006 21:56:54 -0700 "Steve N." wrote in message news:e5nbit$5p4$1@avnika.corp.mot.com... > And so it goes... < snip > > I was in the Phillipines, uh oh! it's comming back ... NAV COM STA PHIL Likewise. I was a CTMSN/CTM3 there. April 1963 - August 1964. Worked in the receiver building. I have run into a lot of guys who were there -- all later than this graybeard. I don't recognize your name, even with the extra u's taken out. John KD6VKW Article: 224941 of rec.radio.amateur.antenna From: "Stan Shankman" Subject: Re: Is the little ball on top of my antenna the ionsphere? Date: Thu, 1 Jun 2006 23:00:02 -0700 Message-ID: <127vktc7lrtoi7b@corp.supernews.com> References: No, it's the Eye-Off-Sphere :-) "Jay" wrote in message news:jOrcg.651$Sf2.175@newsread1.news.pas.earthlink.net... > I put the ball to a metal grinder and I could easily see an outer F layer > and then the E layer. I couldn't find a D layer, but it was dark outside > and there's not supposed to be a D layer at night. Neat how antenna's can > be manufactured to do that. > > Just passed my tech and General on Sunday so I'll be on the bands as > soon as I find out my callsign and get an ionsphere for my antenna. I > destroyed the old one on the grinder and I hear you need a good ionsphere > to shoot good skip and hear far away stations. Reception has been really > shitty lately without the ionsphere. I looked through the last 4 issues of > QST and I couldn't find anyone selling ionsphere's. Where can I get one, > or do I have to buy a whole new antenna? > > Thanks, Jay > Article: 224942 of rec.radio.amateur.antenna Date: Fri, 02 Jun 2006 23:40:56 +1000 From: antenna@antenna.com Subject: test Message-ID: <44803fec$1_1@news.iprimus.com.au> test Article: 224943 of rec.radio.amateur.antenna Date: Fri, 02 Jun 2006 23:41:48 +1000 From: antenna@antenna.com Subject: test Message-ID: <44804021_1@news.iprimus.com.au> test Article: 224944 of rec.radio.amateur.antenna From: Tron Subject: Re: Origins of the Magnetron Date: Fri, 02 Jun 2006 14:18:35 -0000 Message-ID: <1280i5rnl0snk69@corp.supernews.com> References: <463s72hn6rjebqshn3slpe6hk1hlo8ec08@4ax.com> Richard Clark wrote: > > Hi All, > > Just a bit of RF history obtained from "Forty Years of Radio > Research," by George C. Southworth while I was doing some research for > a correspondent: > > "As early as 1921, Dr. A.W. Hull of the General Electric Company > described the characteristics of a device which he called a > magnetron. It consisted of an axial filament surrounded by a > cylindrical plate between which a constant radial electric field > could be impressed. Superimposed on this arrangement and at right > angles to the electric field was an axial magnetic field. This sounds like a Faraday disk motor where the copper or brass disk was replaced by an electron stream in a vacuum: http://w1tp.com/s_motr.jpg > > ... "Later the inductive load was reduced to a tiny Lecher frame. > A magnetron with this configuration was placed inside a small > waveguide by Dr. Harold S. Howe of the University of Michigan to > obtain a top frequency of nearly 50,000 mc. (1938). > > "A few years earlier, 1934, Dr. Cleeton and Professor Williams > also of the University of Michigan had ... discovered a pronounced > absorption band for ammonia at about 27,300 mc. This ultimately > led to a new time-keeping device of high accuracy. > > ... "Finally the plate was made from a single block of copper with > appropriate segments milled inside its hollow periphery, each > representing an individual oscillator. This important step was > taken by physicists at the University of Birmingham in the late > thirties. They also applied plate power in short pulses and at > much higher levels than had been used previously. This was not > only more appropriate for good magnetron operation but it > provided an almost ideal signal for radar use. ... Details of this > device were brought to America first by Sir Robert Watson-Watt and > Drs. Cockcroft and Bowen in September, 1940." > > 73's > Richard Clark, KB7QHC Article: 224945 of rec.radio.amateur.antenna Subject: Re: RF grounding methods for sailboats: A Summary From: chuck Date: Fri, 02 Jun 2006 11:10:41 -0400 Message-ID: <1149260433_149@sp6iad.superfeed.net> References: <16029-447F0B8F-218@storefull-3254.bay.webtv.net> <1149218004.001316.294030@h76g2000cwa.googlegroups.com> gaschafer@comcast.net wrote: > You wrote: >> In article <16029-447F0B8F-218@storefull-3254.bay.webtv.net>, >> richardharrison@webtv.net (Richard Harrison) wrote: >> >>> If "skin effect" prevents penetration to a copper plate on the hull, >>> fine. RF has then made the transfer to the sea at a shallow depth. >>> That`s the goal. >> Bullshit, where do you guys come up with this stuff....Skin Effect is a >> a Boundry Thing, and the hull of the vessel is the "Boundry of the Sea >> Water" even if it is 10 feet below the sea surface. > > Finally someone gets it! This is what Roy said way back in his first > report of his modeling, that the ground plate if fastened to the hull > will be on the surface of the water even if it happens to be several > feet below. The other side of the ground plate is air. In other words > the hull is displacing the water. Unless of course the boat has sunk. It is interesting to speculate about the proportion of displacement currents passing through the air to the inside of the hull and then through the hull to the grounding plate, vs. the proportion passing from the surface along the water-hull interface to the Dynaplate. As Roy pointed out, one reason seawater "works" despite its low conductivity relative to copper is that a high percentage of the "ground" return current is concentrated very close to the antenna where path conductance is high. If the water path >from the surface to the Dynaplate is vertical (four feet) does that mean return currents must pass through four additional feet of seawater and thus will encounter greater losses than if the Dynaplate were at the surface? Or will the vertical water path "collect" the same or even greater return currents than a horizontal water path? I've heard of radials sloping up and away from the antenna at 45 degrees, but 90 degrees? (Assumes tuner ground terminal directly adjacent to Dynaplate on other side of hull) Ought to be easy to model. Interesting, no? > > For the guys that are referencing the N6?? Article about very short > elevated radials over sea water; please note that he is saying those > short elevated radials are tuned with loading coils. > Yes. That is what he reported on his modeling. Elevated radials will not work unless they are 1/4 wave resonant or > tuned with a loading coil. This is not at all obvious to me except at a semantic level. And lest anyone misunderstand, Gary is not suggesting that N6LF made that statement. Is an automobile body (on land) conceptually analogous to non-resonant, elevated radials? Does it work? Would it work less well over seawater (let it levitate or make very quick QSOs)? Would a random length whip on HF work with a tuner and a single, non-resonant wire about 25 feet long, in lieu of the auto body? Would it work less well over seawater? If you're with me this far, the next question is "how much better or worse?". And then on to the other tradeoffs: radiation patterns, safety, simplicity, RF coupling, etc. Alternatively, we can explore why it won't work. > > 73 > Gary K4FMX > 73, Chuck NT3G ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 224946 of rec.radio.amateur.antenna Subject: Re: RF grounding methods for sailboats: A Summary From: chuck Date: Fri, 02 Jun 2006 11:21:20 -0400 Message-ID: <1149261071_191@sp6iad.superfeed.net> References: <16029-447F0B8F-218@storefull-3254.bay.webtv.net> <1149218004.001316.294030@h76g2000cwa.googlegroups.com> <1149260433_149@sp6iad.superfeed.net> chuck wrote: > > As Roy pointed out, one reason seawater "works" despite its low > conductivity relative to copper is that a high percentage of the > "ground" return current is concentrated very close to the antenna where > path conductance is high. If the water path from the surface to the > Dynaplate is vertical (four feet) does that mean return currents must > travel along four additional feet of seawater (at the hull-water interface) and thus will encounter greater losses than if the Dynaplate were at the surface? OOPS! "pass through" should be changed to "travel along" and the parenthetical expression (at the hull-water interface) should be added for clarification. Text above has been so edited. Sorry about that. Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 224947 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: RF grounding methods for sailboats: A Summary Date: Fri, 2 Jun 2006 12:04:03 -0500 Message-ID: <23775-44806F83-11@storefull-3257.bay.webtv.net> References: <1149260433_149@sp6iad.superfeed.net> Chuck wrote: "If thee water parh from the surface to the Dynaplate is vertical (four feet) does that mean return currents must pass through four additional feet of seawater and thus encounter greater losses than if the Dynaplate were at the surface?" Well, the Dynaplate is at the surface of the water in contact with the hull. That surface makes a turn to the horizontal at the sea surface. The Dynaplate could also be connected by copper strap(s) on the extertior of the insulated hull so as to contact the sea at a shallower depth depending on the list (tilt) and trim of the boat. Capacitive coupling through an insulated hull is usually comparatively easy at RF. Best regards, Richard Harrison, KB5WZI Article: 224948 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: Is the little ball on top of my antenna the ionsphere? Date: Fri, 2 Jun 2006 12:42:35 -0500 Message-ID: References: <127vktc7lrtoi7b@corp.supernews.com> "Stan Shankman" wrote in message news:127vktc7lrtoi7b@corp.supernews.com... > No, it's the Eye-Off-Sphere :-) > Hey! I like that! 73, Steve, k9DCi Article: 224949 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: RF grounding methods for sailboats: A Summary Date: Fri, 02 Jun 2006 22:24:31 -0700 Message-ID: <128278grmhthsab@corp.supernews.com> References: <1148994725_36063@sp6iad.superfeed.net> <6ggr72509n8k0ulii7a3j574e6ogiuhrbp@4ax.com> <1149107678_2377@sp6iad.superfeed.net> <447ec69c_1@news.iprimus.com.au> bob wrote: > . . . > One thing i am curious about is that if you suspend a radiator or > conductor well below skin depth in air whats the radiation efficiency > like of that conductor? To me on a yacht it looks like a conductor > suspended in a U channel suspended in air with the top open and > exposed. Maybe it will operate like a waveguide with some cut off > frequency, this is a wild guess.Maybe someone who can model conductors > below ground can model this. Most yachts have at least 3ft of freeboard > above water to play with. > > But who knows there seems to conflicting advice on several points. > Maybe Roy can clarify all these issues with his models. There's no good way to model this situation with the tools I have. Conceptually, though, you can get a fair idea by imagining the sea to be made of metal. The boat makes a depression in the surface, and you can connect to the metal at the bottom of the depression just as you can anywhere else on its surface. Imagine that the depression is perfectly round and symmetrical, with a grounded vertical extending up from its center. The current flowing into the "ground" connection at the bottom of the depression will flow along the conductor's surface, up the sides of the "dish" to the flat water surface. The total current flowing from the center of the dish upward to the flat surface will equal the current flowing up the vertical wire near its base. The fields from the two will nearly cancel, so there'll be little radiation from the vertical in the region below the flat surface of the water. The vertical above that point should radiate normally. This simplification will of course be modified by the reality of a non-symmetrical hull, but it helps in getting a general idea of what will happen. Another way to look at the situation is to view the depression as the outer conductor of a shorted coaxial cable, with the "ground wire" extending down to its center as its center conductor, and the shorted end the bottom of the depression. This shows you'd get some inductive reactance in your connection to the surface of the water. A rough calculation would probably get you in the ballpark of the actual value. This doesn't represent loss, however. The main thing, though, is that connection to the water requires a conductor either in contact with or capacitively coupled to the water's surface or only a very short distance below it (assuming salt water), whether the surface is below the boat's hull in a depression or on the flat surface of the ocean. Roy Lewallen, W7EL Article: 224950 of rec.radio.amateur.antenna From: "Ken Bessler" Subject: 6m 3el quad question Message-ID: Date: Sat, 3 Jun 2006 09:02:19 -0500 I just finished construction but my holes in the boom for the spreaders were not perfectly square so my reflector is rotated about 5-10 degrees out of line with the other elements. Does this matter that much? I could cut the boom, rotate the reflector into alignment and re-attach if it was that important. Is it? -- 73's de Ken KG0WX - Kadiddlehopper #11808, Flying Pigs #-1055, Grid EM17io, FT-857D, AL-84, Elecraft XG2, 4SQRP Tenna Dipper, Heath GD-1B Article: 224951 of rec.radio.amateur.antenna From: "Cecil Moore" References: Subject: Re: I was going through about ten years of ham catalogs, and I noticed a disturbing trend. Message-ID: Date: Sat, 03 Jun 2006 14:23:33 GMT "Morse or Re-Morse" wrote > Radio Shack. You got questions, we got blank stares. My 17 year old RS Optimus speakers gave up the ghost. I went into a Radio Shack and was told that not only does RS not sell speakers like that anymore, but speakers with one tweeter plus one mid-range plus one woofer were not even manufactured anymore and that it takes half a dozen modular speakers to set up a system nowadays. I went over to Fry's Electronics and found exactly what I was looking for from Cambridge Soundworks. The woofer only goes down to 40 Hz but for my karaoke system, that's good enough. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224952 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: Subject: Re: 6m 3el quad question Message-ID: Date: Sat, 3 Jun 2006 10:31:24 -0400 "Ken Bessler" wrote in message news:LDggg.35496$4H.30435@dukeread03... >I just finished construction but my holes in the boom for > the spreaders were not perfectly square so my reflector > is rotated about 5-10 degrees out of line with the other > elements. Does this matter that much? I could cut the > boom, rotate the reflector into alignment and re-attach > if it was that important. Is it? > -- > 73's de Ken KG0WX - Kadiddlehopper #11808, > Flying Pigs #-1055, Grid EM17io, FT-857D, AL-84, > Elecraft XG2, 4SQRP Tenna Dipper, Heath GD-1B > > Electrically - very little, if anything. Loop (closed) doesn't know what polarization it is. Esthetically - it will look (slightly) crooked, need to point in direction that will hide it from the major people traffic area :-) 73 Yuri, K3BU Article: 224953 of rec.radio.amateur.antenna From: "Cecil Moore" References: <17757-44746714-21@storefull-3257.bay.webtv.net> <1148486661.748365.219740@u72g2000cwu.googlegroups.com> <1149261241.354995.121520@y43g2000cwc.googlegroups.com> Subject: Re: FIGHT! FIGHT! FIGHT! Message-ID: <26hgg.130896$F_3.20730@newssvr29.news.prodigy.net> Date: Sat, 03 Jun 2006 14:34:38 GMT wrote > Electrically, > antennas are very linear (I believe) even when their current > distribution along the element length is not. > > I stopped posting when I realized we were discussing two different > things. In a linear system, there only needs to be a straight line function between the input and output. The actual signals on the input wouldn't be very useful if only straight line functions were allowed on that input. The current distribution along an antenna element length only ever approximates a straight line. The only requirement for that current to obey the rules for a linear system is that it be a linear function of the source current and it is at every point. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224954 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: RF grounding methods for sailboats: A Summary Date: Sat, 3 Jun 2006 15:19:32 -0500 Message-ID: <25601-4481EED4-37@storefull-3258.bay.webtv.net> References: <1149261071_191@sp6iad.superfeed.net> Chuck wrote: "If the water path from the surface of the Dynaplate is vertical (four feet) does that mean return currents must travel along four additional feet of seawater (at the hull-water interface)---? Maybe, but there is a lot of area in that path. The hull-water interface includes the entire submerged surface of the hull. It has been assumed in this thread that the sail-boat hull is fiberglass, an insulator. The impedance of fiberglass is vastly different from that of seawater. The great mismatch between fiberglass and seawater means a radio wave traveling along one of the surfaces won`t be readily absorbed into the other. Dynaplate is a name given copperfoil on a roll. Dynaplate is also a name given a copper plate which has been etched to increase surface area thereby increasing its contact area with water. The surface of seawater contacting a boat hull is continuous with the horizontal surface of the sea. Vertical polarization is effective over seawater. Horizontal polarization is ineffective. The sea short-circuits the voltage wave. A horizontal wire can produce vertically polarized radiation. The Beverage antenna works over poor soil. On page 720 of Kraus` 3rd edition of "Antennas" is the "Flush Disc" antenna which produces vertically polarized radiation over a highly conductive surface. It`s a radiator in a pit and should be useful in a vessel. Best regards, Richard Harrison, KB5WZI Article: 224955 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Special Tower Bolts Date: Sat, 3 Jun 2006 19:38:16 -0500 Message-ID: <25156-44822B78-658@storefull-3252.bay.webtv.net> References: g. beat wrote: "Avoid check surplus bolts of unknown origin." All bolts may have questionable origin. In addition to the bolt`s shear strength, it may loose its head at too low a torque. Use a torque wrench to measure the point at which several bolts lose their heads. Best regards, Richard Harrison, KB5WZI Article: 224956 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Origins of the Magnetron Date: Sat, 3 Jun 2006 20:10:48 -0500 Message-ID: <25156-44823318-660@storefull-3252.bay.webtv.net> References: Ian, GM3SEK wrote: "Sure, but none of those (bedapring antenna arrays) would fly very well." It`s been a long time now but I believe investigation showed the army`s new radar (earthborne) got good echos from the approaching Japanese arircraft on December 7, 1941, but the top brass rejected the reports in disbelief of either the new equipment or the audacity of the Japanese Navy. That attack changed naval warfare forever. Lot more respect for both aircraft and radar ever since. Best regards, Richard Harrison, KB5WZI Article: 224957 of rec.radio.amateur.antenna From: "Jimmie D" Subject: Choke /BALUN Message-ID: Date: Sat, 3 Jun 2006 23:05:02 -0400 I want needinfo on the type of cores do I need to use with RG58 and RG 214 to make a choke type BALUN at 2m. I am building a vertical dipole out of 1 inch al tubing. coax will pass through the bottom half othe dipole with the sheild fastend at the middle of the bottom piece and cneter conductor fastened to the top piece of al. Initial test indicate I have RF on the shield and need some decoupling. Winding the coax into a coil certainly helped but this has prevented me from placing the antenna in a fiberglass tube the way I had planned. Article: 224958 of rec.radio.amateur.antenna From: nospam@nouce.bellatlantic.net Subject: Re: Origins of the Magnetron Message-ID: References: <18384-447E8228-1115@storefull-3256.bay.webtv.net> <6nPfg.28256$QP4.810@fed1read12> Date: Sun, 04 Jun 2006 03:07:59 GMT On Fri, 2 Jun 2006 07:35:24 +0100, Ian White GM3SEK wrote: >Sal M. Onella wrote: >> >>"Ian White GM3SEK" wrote in message >>news:kmieVPE+IpfEFA1P@ifwtech.co.uk... >> >> >>> Those were the phased arrays for the earlier VHF radar, and consisted of >>> two or four two-element yagis clustered around the nose (of a >>> two-engined aircraft, obviously). This gave a fairly good >>> forward-looking capability. Both sides did much the same, and given the >>> relatively long wavelength, it's hard to think how better to do it. >>> >>> The huge benefit of the magnetron was that it operated at much shorter >>> wavelengths, which frees up the antenna design and provides much better >>> spatial resolution - witness the downward-looking "H2S" radar which was >>> the magnetron's first major deployment. >> >>The VHF radars were still around into the late 1970's, maybe beyond. The US >>Navy had them on carriers for air search. I think the nomenclature was >>AN/SPS-29 and/or AN/SPS-37. The one I recall was in the 218 - 220 MHz and >>it was hell on TV channel 13! The antenna was referred to as a bedspring >>array; the rectangular framework for the dipole radiating elements resembled >>a giant bedspring. >> > >Sure, but none of those would fly very well. The discussion was really >about airborne radar, where there are tough limits on antenna size. P38s, Spitfires and other aircraft setup for night attack or bombing did have a smaller high VHF radars using smaller 8 element bedspring arrays. They proved very effective. VHF and UHF radar has a better ability to peek over the horizon and at the time when reciever for uhf were still new tech offered the best range/power ratios. The magnetron moved effort to the milimeter bands at high power outputs where small high gain antennas were practical thus negating the need for high gain recievers. Allison Article: 224959 of rec.radio.amateur.antenna From: "Cecil Moore" References: Subject: Re: Choke /BALUN Message-ID: Date: Sun, 04 Jun 2006 03:47:46 GMT "Jimmie D" wrote: >I want needinfo on the type of cores do I need to use with RG58 and RG 214 >to make a choke type BALUN at 2m. I am building a vertical dipole out of 1 >inch al tubing. coax will pass through the bottom half othe dipole with the >sheild fastend at the middle of the bottom piece and cneter conductor >fastened to the top piece of al. Initial test indicate I have RF on the >shield and need some decoupling. For single band operation, a simple decoupling stub or sleeve will probably work. This is discussed in the ARRL Antenna Book. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224960 of rec.radio.amateur.antenna Date: Sun, 04 Jun 2006 09:24:04 -0400 From: "J. D. B." Subject: Re: Elimination of CW is a loss in the number of ways we can communicate References: Message-ID: <9e847$4482def6$d06640f9$28274@FUSE.NET> The FCC is not requiring specific testing for PSK31, RTTY, Hellschreiber, Olivia, etc. and all those modes seem to be used pretty extensively on all the bands. Not to mention, programs like MixW and especially MultiPSK do an excellent job of sending a receiving CW. I see all the modes continuing to flourish in the future even if a specific test for one mode (CW) goes away. Brian Hill wrote: > "Silent Key" wrote in message > news:NOw6g.6936$An2.3601@newsread2.news.pas.earthlink.net... >> What's the purpose of ham radio, To have fun talking about rigs and >> weather, or to be able to communicate? >> >> To be able to communicate when no one else can communicate and to advance >> radio knowledge & theory? >> >> What does part 97 say about this? Why does the ARRL ignore it? >> >> When CW is lost, new hams will be just like CB'ers and SWL's, or some >> other lower life form of radio hobbiest. You name it. >> >> SC > > Nobody said you had to quit. Keep pounding. > > BH > > Article: 224961 of rec.radio.amateur.antenna Date: Sun, 04 Jun 2006 10:18:28 -0400 From: "J. D. B." Subject: Re: APRSpoint: memorial day special References: <1148837974.520652.311110@u72g2000cwu.googlegroups.com> Message-ID: The only issue with APRSPoint is that support and upgrades are sorely lacking. The Yahoo group he runs is censored so that any suggestions or criticisms of his product are not posted. He needs to really upgrade this program. It is one of the most expensive and also has the least amount of features. Nice start, but the author needs to really spend some time getting this program up to where all the other APRS programs are in functionality. hxc98@yahoo.com wrote: > APRSPoint is the latest APRS implementation and it is being used in > vehicle tracking, search and rescue, emergency communication and many > other areas. It allows you to track persons or objects via rf or > internet. It is constantly being updated with new features and > improvements. We are offerring a special discount for this memorial day > weekend. Please visit http://www.aprspoint.com for details and lots of > helpful information about APRS. Thanks. > Article: 224962 of rec.radio.amateur.antenna From: nospam@nouce.bellatlantic.net Subject: Re: Origins of the Magnetron Message-ID: References: <18384-447E8228-1115@storefull-3256.bay.webtv.net> <6nPfg.28256$QP4.810@fed1read12> Date: Sun, 04 Jun 2006 15:08:58 GMT On Sun, 4 Jun 2006 09:12:09 +0100, Ian White GM3SEK wrote: >Allison wrote: >>On Fri, 2 Jun 2006 07:35:24 +0100, Ian White GM3SEK >> wrote: >> >>>Sal M. Onella wrote: >>>> >>>>"Ian White GM3SEK" wrote in message >>>>news:kmieVPE+IpfEFA1P@ifwtech.co.uk... >>>> >>>> >>>>> Those were the phased arrays for the earlier VHF radar, and consisted of >>>>> two or four two-element yagis clustered around the nose (of a >>>>> two-engined aircraft, obviously). This gave a fairly good >>>>> forward-looking capability. Both sides did much the same, and given the >>>>> relatively long wavelength, it's hard to think how better to do it. >>>>> >>>>> The huge benefit of the magnetron was that it operated at much shorter >>>>> wavelengths, which frees up the antenna design and provides much better >>>>> spatial resolution - witness the downward-looking "H2S" radar which was >>>>> the magnetron's first major deployment. >>>> >>>>The VHF radars were still around into the late 1970's, maybe beyond. The US >>>>Navy had them on carriers for air search. I think the nomenclature was >>>>AN/SPS-29 and/or AN/SPS-37. The one I recall was in the 218 - 220 MHz and >>>>it was hell on TV channel 13! The antenna was referred to as a bedspring >>>>array; the rectangular framework for the dipole radiating elements resembled >>>>a giant bedspring. >>>> >>> >>>Sure, but none of those would fly very well. The discussion was really >>>about airborne radar, where there are tough limits on antenna size. >> >>P38s, Spitfires and other aircraft setup for night attack or bombing >>did have a smaller high VHF radars using smaller 8 element bedspring >>arrays. They proved very effective. >> > >As far as I know, these VHF arrays were only installed on the nose of >twin-engined or four-engined aircraft. On a single-engined aircraft like >the Spitfire, the antenna would have been behind the propeller. Did you >mean the Mosquito? Yes the Mosquito, the Spitfire for night ops had a downward looking antenna system. >There were also some rearward-looking VHF/UHF radars using a simple >2-element antenna, to warn of aircraft approaching from anywhere within >a large rearward beamwidth. > >A common feature of all these early airborne VHF/UHF systems was that >the antennas were fixed, so the view was always relative to the >direction of the aircraft. Most were. there were a few early steerable arrays on bigger aircraft. However late in the war there were downward forward looking arrangements for terrain mapping (bombing) and inteligence. >>VHF and UHF radar has a better ability to peek over the horizon and at >>the time when reciever for uhf were still new tech offered the best >>range/power ratios. > >Hence VHF/UHF was favored for shipborne use, where the horizon range is >limited by the relatively low antenna height. > >>The magnetron moved effort to the milimeter bands >>at high power outputs where small high gain antennas were practical >>thus negating the need for high gain recievers. >> >Yup... and the small size eventually opened the way to steerable >antennas too. Article: 224963 of rec.radio.amateur.antenna From: "LLOYD THE LOSER DAVIES" References: <1147047627.949564.83230@y43g2000cwc.googlegroups.com> <1147549161.064623.59130@j33g2000cwa.googlegroups.com> <1147586170.894157.292250@d71g2000cwd.googlegroups.com> <38c8.gop.17.1@news.alt.net> <1147832357.964390.122730@i40g2000cwc.googlegroups.com> <1148093850.852066.18100@u72g2000cwu.googlegroups.com> <1148242353.491923.5580@u72g2000cwu.googlegroups.com> <%Ardg.7747$y4.1609@newsread2.news.pas.earthlink.net> Subject: Re: Elimination of CW is a loss in the number of ways we can communicate with other. Date: Sun, 4 Jun 2006 13:26:41 -0400 Message-ID: <44830a75$0$26866$88260bb3@free.teranews.com> "Dan/W4NTI" wrote in message news:%Ardg.7747$y4.1609@newsread2.news.pas.earthlink.net... > > "Lloyd" wrote in message > news:DRL017833.2458F8789@tarrnews.net... >> On 21 May 2006 13:12:33 -0700, an old friend drooled: >>> Dan/W4NTI wrote: >>> > Or just a common drunk or dope addict that gets worse as >>> > the night goes on? >>> more libel >>> >>> how drool Dan >> >> Dan doesn't drool. Right, Dan? > > No I don't. Why is this particular idiotic thread in every major ham > radio group? It finally dropped out of DX, and now I find it in > "equipment". How about you children make your own little group, all climb > into it, and make each other happy. > > Dan/W4NTI > > Even if I could learn the CW, I'm too stupid to pass the written test. I have this congenital problem, you see. Life is NOT good for me. I suffer from Microcephalic Dwarfism and I've been afflicted with it since I can remember. Definition: These syndromes associate growth retardation with microcephaly and various facial anomalies. My forehead is smaller than that of a normal person and my cranial cavity is little larger than that of a Florida orange. My sloping forehead has only one advantage in that it allows me to insert it into my rectal cavity with little or no pain. While less than comfortable, and while it impedes clear speech I am able to keep my ears warm in the coldest of climates, but those are the good points. I have suffered from extreme retardation all my life and have recently been considering placing my head in the oven. I am betting that the accumulated yeast in my mouth will aid me in blowing my head off at 350 degrees, thus ending it all. You guys have no idea of what torture it is to live with my afflictions. You will miss me when I am gone. -- Posted via a free Usenet account from http://www.teranews.com Article: 224964 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> Subject: Re: Choke /BALUN Message-ID: Date: Sun, 04 Jun 2006 18:29:11 GMT This is a multi-part message in MIME format. ------=_NextPart_000_0011_01C687DA.DDE01BB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable "Will" wrote: >=20 > How do you figure the lower "coaxial sleave" dimentions. It's usually 1/4WL long. The theory is to turn that 1/4WL of feedline into a transmission line where the currents on the outside of the original shield are balanced by the inside=20 shield on the sleeve which balances the antenna currents. It functions over a certain single bandwidth. --=20 73, Cecil http://www.qsl.net/w5dxp ------=_NextPart_000_0011_01C687DA.DDE01BB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
"Will" <echocomms@hotmail.com>=20 wrote:
>
> How do you figure the = lower "coaxial=20 sleave" dimentions.
 
It's usually 1/4WL long. The theory is = to turn=20 that 1/4WL of
feedline into a transmission line where = the=20 currents on the
outside of the original shield = are balanced=20 by the inside
shield on the=20 sleeve which balances the antenna currents.
It functions over a certain single=20 bandwidth.
--
73, Cecil  http://www.qsl.net/w5dxp
------=_NextPart_000_0011_01C687DA.DDE01BB0-- Article: 224965 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Origins of the Magnetron Date: Sun, 4 Jun 2006 13:33:22 -0500 Message-ID: <1374-44832772-396@storefull-3255.bay.webtv.net> References: Reg, G4FGQ weote: "As the radar operator over the China Sea, I was once severely cursed (reoremanded) over the intercom by the skipper for getting ourselves lost immediately following a tight turn." On my ship, most of the crew was sleepless most of the time while we were underway. We had two 4-hour watches each day at our sea detail. Plus, we had to turn-to on our regular work details during dayrime hours if we weren`t on watch. But, the killer was the dawn and dusk general quarters positions we had to man every day while traveling in a war zone. You were really lucky if your assigned watch time sometimes cincided with work-detail time. The result of all this sleep loss was some cat-napping on the bridge in addition to elsewhere aboard. Our top speed was 14 knots which made us faster than a liberty ship, so at times we got convoy escort duty. We had antiaircraft guns, 50 ca., 20 mm, and 40 mm. My gq position was on the latter. Whenever the brdge awakened after a doze in convoy, someone would often shout down through the voice tube to the radar operator: "Geez! how close is that ship ahead? Whereupon, the operator would push or pull himself away from a PPI tube covered with false sea return, poke his head out a porthole, then scream his best estimate back up the voice tube. That`s how he avoided being scolded. Best regards, Richard Harrison, KB5WZI Article: 224966 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Choke /BALUN Message-ID: References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> Date: Sun, 04 Jun 2006 21:32:01 GMT On Sun, 04 Jun 2006 18:29:11 GMT, "Cecil Moore" wrote: ... What's with the HTML format Cecil? Owen -- Article: 224967 of rec.radio.amateur.antenna Subject: Re: Elimination of CW is a loss in the number of ways we can communicate with other. From: Radio Buff References: <9e847$4482def6$d06640f9$28274@FUSE.NET> Message-ID: Date: Sun, 04 Jun 2006 22:23:52 GMT "J. D. B." wrote in news:9e847$4482def6$d06640f9$28274@FUSE.NET: > The FCC is not requiring specific testing for PSK31, RTTY, > Hellschreiber, Olivia, etc. and all those modes seem to be used pretty > extensively on all the bands. Not to mention, programs like MixW and > especially MultiPSK do an excellent job of sending a receiving CW. I see > all the modes continuing to flourish in the future even if a specific > test for one mode (CW) goes away. Any retard can use a computer. Look around. Article: 224968 of rec.radio.amateur.antenna Subject: Re: I was going through about ten years of ham catalogs, and I noticed a disturbing trend. From: Slow Code References: Message-ID: <94Jgg.9081$921.5558@newsread4.news.pas.earthlink.net> Date: Sun, 04 Jun 2006 22:24:05 GMT "Cecil Moore" wrote in news:FXggg.130895$F_3.107482@newssvr29.news.prodigy.net: > "Morse or Re-Morse" wrote >> Radio Shack. You got questions, we got blank stares. > > My 17 year old RS Optimus speakers gave up the ghost. I went into > a Radio Shack and was told that not only does RS not sell speakers > like that anymore, but speakers with one tweeter plus one mid-range > plus one woofer were not even manufactured anymore and that it > takes half a dozen modular speakers to set up a system nowadays. > > I went over to Fry's Electronics and found exactly what I was > looking for from Cambridge Soundworks. The woofer only goes > down to 40 Hz but for my karaoke system, that's good enough. A microphone, a six-pack, a karaoke system, & you're a star. :-) sc Article: 224969 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> Subject: Re: Choke /BALUN Message-ID: <8HMgg.46032$Lm5.40693@newssvr12.news.prodigy.com> Date: Mon, 05 Jun 2006 02:30:28 GMT "Owen Duffy" wrote: > What's with the HTML format Cecil? I've switched over from Netscape to Outlook Express and have no idea what I am doing. I can't seem to get Outlook Express to compose anything in Courier fixed font. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224970 of rec.radio.amateur.antenna From: "Cecil Moore" References: <94Jgg.9081$921.5558@newsread4.news.pas.earthlink.net> Subject: Re: I was going through about ten years of ham catalogs, and I noticed a disturbing trend. Message-ID: Date: Mon, 05 Jun 2006 02:33:29 GMT "Slow Code" wrote: > A microphone, a six-pack, a karaoke system, & you're a star. :-) Yep, see: http://www.qsl.net/w5dxp/w5dxp.jpg -- 73, Cecil http://www.qsl.net/w5dxp Article: 224971 of rec.radio.amateur.antenna From: "Cecil Moore" References: <17757-44746714-21@storefull-3257.bay.webtv.net> <1148486661.748365.219740@u72g2000cwu.googlegroups.com> <1149261241.354995.121520@y43g2000cwc.googlegroups.com> <26hgg.130896$F_3.20730@newssvr29.news.prodigy.net> <1149460689.301329.175570@g10g2000cwb.googlegroups.com> Subject: Re: FIGHT! FIGHT! FIGHT! Message-ID: Date: Mon, 05 Jun 2006 02:36:16 GMT wrote: > Cecil's point that doubling antenna current will double the current at > each point in the antenna (I'm rephrasing) has a dual in mixers: > doubling any signal will double all the mixer's ouputs due to that > signal alone, and not any other outputs. Yep, as long as system linearity is maintained. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224972 of rec.radio.amateur.antenna From: "M." References: <9e847$4482def6$d06640f9$28274@FUSE.NET> Subject: Re: Elimination of CW is a loss in the number of ways we can communicate with other. Message-ID: Date: Mon, 5 Jun 2006 04:29:33 -0500 "Radio Buff" wrote in message news:Y3Jgg.9077$921.5844@newsread4.news.pas.earthlink.net... > "J. D. B." wrote in > news:9e847$4482def6$d06640f9$28274@FUSE.NET: > >> The FCC is not requiring specific testing for PSK31, RTTY, >> Hellschreiber, Olivia, etc. and all those modes seem to be used pretty >> extensively on all the bands. Not to mention, programs like MixW and >> especially MultiPSK do an excellent job of sending a receiving CW. I see >> all the modes continuing to flourish in the future even if a specific >> test for one mode (CW) goes away. > > > > Any retard can use a computer. Look around. Obviously! Article: 224973 of rec.radio.amateur.antenna From: "Jimmie D" References: Subject: Re: Choke /BALUN Message-ID: Date: Sun, 4 Jun 2006 23:26:56 -0400 "Cecil Moore" wrote in message news:CJsgg.131091$F_3.95183@newssvr29.news.prodigy.net... > "Jimmie D" wrote: >>I want needinfo on the type of cores do I need to use with RG58 and RG 214 >>to make a choke type BALUN at 2m. I am building a vertical dipole out of 1 >>inch al tubing. coax will pass through the bottom half othe dipole with >>the sheild fastend at the middle of the bottom piece and cneter conductor >>fastened to the top piece of al. Initial test indicate I have RF on the >>shield and need some decoupling. > > For single band operation, a simple decoupling stub or sleeve will > probably work. This is discussed in the ARRL Antenna Book. > -- > 73, Cecil http://www.qsl.net/w5dxp > Would be difficult to incorporate into my design Article: 224974 of rec.radio.amateur.antenna From: "Jimmie D" References: Subject: Re: Choke /BALUN Message-ID: Date: Sun, 4 Jun 2006 23:38:51 -0400 "Jimmie D" wrote in message news:l0sgg.73153$iB2.27815@bignews4.bellsouth.net... >I want needinfo on the type of cores do I need to use with RG58 and RG 214 >to make a choke type BALUN at 2m. I am building a vertical dipole out of 1 >inch al tubing. coax will pass through the bottom half othe dipole with the >sheild fastend at the middle of the bottom piece and cneter conductor >fastened to the top piece of al. Initial test indicate I have RF on the >shield and need some decoupling. Winding the coax into a coil certainly >helped but this has prevented me from placing the antenna in a fiberglass >tube the way I had planned. > Thanks all, found what I was looking for at Wireman. Article: 224975 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> <1149500185.456097.149290@h76g2000cwa.googlegroups.com> Subject: Re: Choke /BALUN Message-ID: Date: Mon, 05 Jun 2006 13:46:02 GMT "Will" wrote: > My thaught is with the 1"mast inside of the sleave (insulated and > centered only connected at the top) what does the added capacitance do > to the sleave lenght? I'm sorry, I don't know what the velocity factor would be in that configuration. If you sampled the common mode current and tuned the frequency for a minimum, it might give you an idea of the velocity factor. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224976 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> <8HMgg.46032$Lm5.40693@newssvr12.news.prodigy.com> Subject: Re: Choke /BALUN Message-ID: Date: Mon, 05 Jun 2006 13:55:34 GMT "John, N9JG" wrote: > Try Tools | Options | Compose | News: Font Settings Of course, I have set the font to Courier but right now, even though I have "Plain Text" selected, the composing font is Times New Roman. If I select "Rich Text", then it will compose in Courier but that is HTML. I once forgot to switch to plain text before sending and it apparently posted HTML. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224977 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> <1149500185.456097.149290@h76g2000cwa.googlegroups.com> Subject: Re: Choke /BALUN Message-ID: <%nXgg.46192$Lm5.6933@newssvr12.news.prodigy.com> Date: Mon, 05 Jun 2006 14:40:59 GMT I've gotten a few emails asking how a 1/4WL wire stub can be used as a balun on a single band like 2m. Just connect the wire to the element driven by the coax center conductor and connect the other end to the braid 1/4WL down the coax. In fixed font: | | | Dipole | | +====================================coax braid +------------------------------------coax center conductor | | ===================+==============coax braid | spacing | +---------------------+ | 1/4WL stub | The current at the feedpoint sees a very high impedance looking back down the *outside* braid of the feedline because it is looking into a shorted 1/4WL stub. Often, a piece of similar coax is used for the 1/4WL stub. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224978 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: RF grounding methods for sailboats: A Summary Date: Mon, 05 Jun 2006 12:58:50 -0400 Message-ID: References: <1148994725_36063@sp6iad.superfeed.net> <6ggr72509n8k0ulii7a3j574e6ogiuhrbp@4ax.com> <1149107678_2377@sp6iad.superfeed.net> <447ec69c_1@news.iprimus.com.au> <128278grmhthsab@corp.supernews.com> Roy Lewallen wrote: > bob wrote: >> . . . >> One thing i am curious about is that if you suspend a radiator or >> conductor well below skin depth in air whats the radiation efficiency >> like of that conductor? To me on a yacht it looks like a conductor >> suspended in a U channel suspended in air with the top open and >> exposed. Maybe it will operate like a waveguide with some cut off >> frequency, this is a wild guess.Maybe someone who can model conductors >> below ground can model this. Most yachts have at least 3ft of >> freeboard above water to play with. >> >> But who knows there seems to conflicting advice on several points. >> Maybe Roy can clarify all these issues with his models. > > There's no good way to model this situation with the tools I have. > Conceptually, though, you can get a fair idea by imagining the sea to be > made of metal. The boat makes a depression in the surface, and you can > connect to the metal at the bottom of the depression just as you can > anywhere else on its surface. > > Imagine that the depression is perfectly round and symmetrical, with a > grounded vertical extending up from its center. The current flowing into > the "ground" connection at the bottom of the depression will flow along > the conductor's surface, up the sides of the "dish" to the flat water > surface. The total current flowing from the center of the dish upward to > the flat surface will equal the current flowing up the vertical wire > near its base. The fields from the two will nearly cancel, so there'll > be little radiation from the vertical in the region below the flat > surface of the water. The vertical above that point should radiate > normally. This simplification will of course be modified by the reality > of a non-symmetrical hull, but it helps in getting a general idea of > what will happen. > > Another way to look at the situation is to view the depression as the > outer conductor of a shorted coaxial cable, with the "ground wire" > extending down to its center as its center conductor, and the shorted > end the bottom of the depression. This shows you'd get some inductive > reactance in your connection to the surface of the water. A rough > calculation would probably get you in the ballpark of the actual value. > This doesn't represent loss, however. > > The main thing, though, is that connection to the water requires a > conductor either in contact with or capacitively coupled to the water's > surface or only a very short distance below it (assuming salt water), > whether the surface is below the boat's hull in a depression or on the > flat surface of the ocean. Back around the beginning of this thread a thought occurred to me, and I'm surprised that no one else mentioned it. Unless we are planning on putting out ship on the great Salt lake, of one of the few other salt water inland lakes or seas, we're going to be putting the thing in the ocean. Immediately, one sees that if a ground is at the surface of the water, at many points it will be 4 or more feet under the water. Dem boats rock! There are moments that it will be quite a distance under water, depending on the sea state. Depending on the load, the water line is going to be different, and will be changing constantly as fuel and food is used. Certainly any capacitive coupling through the hull makes for a variable capacitor? Does this have an effect? Will we eventually come to the conclusion that we can't put radios on ships?? ;^) - 73 de Mike KB3EIA - Article: 224979 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: RF grounding methods for sailboats: A Summary Date: Mon, 05 Jun 2006 11:33:52 -0700 Message-ID: <1288u8idqtf9b0a@corp.supernews.com> References: <1148994725_36063@sp6iad.superfeed.net> <6ggr72509n8k0ulii7a3j574e6ogiuhrbp@4ax.com> <1149107678_2377@sp6iad.superfeed.net> <447ec69c_1@news.iprimus.com.au> <128278grmhthsab@corp.supernews.com> Michael Coslo wrote: > > Back around the beginning of this thread a thought occurred to me, > and I'm surprised that no one else mentioned it. > > Unless we are planning on putting out ship on the great Salt lake, > of one of the few other salt water inland lakes or seas, we're going to > be putting the thing in the ocean. > > Immediately, one sees that if a ground is at the surface of the > water, at many points it will be 4 or more feet under the water. Dem > boats rock! There are moments that it will be quite a distance under > water, depending on the sea state. Use a bare wire, and the top few inches will do the job regardless of how much additional wire goes below the water. As I've said before, there's no harm in having additional wire below the water; it simply doesn't do anything useful. The problem is that as the boat rocks, the length of the wire to the ocean surface will vary in length, which will change the antenna's impedance. So a plate just inside or outside the bottom of the hull (or someplace that's always below the water line) would seem to me a better idea from a practical standpoint. Surely some boater who understood basic electromagnetics has thought about this and devised a method that's both practical and effective. > Depending on the load, the water line is going to be different, and > will be changing constantly as fuel and food is used. > > Certainly any capacitive coupling through the hull makes for a > variable capacitor? Does this have an effect? What will cause it to vary? In any case, just make the capacitance large enough so the reactance is always small compared to the ground impedance, then it won't matter. > Will we eventually come to the conclusion that we can't put radios on > ships?? ;^) It wouldn't surprise me if some folks reach that conclusion. Millions firmly believe much more ridiculous things. Roy Lewallen, W7EL Article: 224980 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: H FIELD ANTENNAS? Date: Mon, 05 Jun 2006 11:38:44 -0700 Message-ID: <1288uhmljvib979@corp.supernews.com> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> Any theory that predicts any antenna can produce an H field without an E field, or that the H field is unusually large beyond a fraction of a wavelength from an antenna(*), is flawed. So you're free to make up any theory you like, and it'll be just as accurate. (*) Or, from a receiving standpoint, that an antenna responds only to an H field or it responds more strongly to an H field beyond a fraction of a wavelength from the antenna. Roy Lewallen, W7EL justin.gill@tesco.net wrote: > Is anyone aware of any sources of information/theory on H Field > antennas, such as the Chelton Loop for HF? > Article: 224981 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1148994725_36063@sp6iad.superfeed.net> <6ggr72509n8k0ulii7a3j574e6ogiuhrbp@4ax.com> <1149107678_2377@sp6iad.superfeed.net> <447ec69c_1@news.iprimus.com.au> <128278grmhthsab@corp.supernews.com> <1288u8idqtf9b0a@corp.supernews.com> Subject: Re: RF grounding methods for sailboats: A Summary Message-ID: Date: Mon, 05 Jun 2006 18:58:53 GMT "Roy Lewallen" wrote: > Michael Coslo wrote: >> Will we eventually come to the conclusion that we can't put radios on >> ships?? ;^) > > It wouldn't surprise me if some folks reach that conclusion. Millions > firmly believe much more ridiculous things. Since the feedpoint impedance of a dipole changes as it blows in the wind, guess we also can't use them on windy days. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224982 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Give up CB for ham? Date: Mon, 05 Jun 2006 14:16:36 -0500 Message-ID: <12890oj2arv1h8e@corp.supernews.com> References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> patk1212@gmail.com wrote: > Alot of people are telling me that CB is just for inbred hicks and that > I should replace the CB in my truck with a ham radio. What do you > thjink? > Both services have their place. I would keep the CB and install a multi-band Ham radio such as the ICOM IC-706MKIIG or a Kenwood or Yaesu and a multi-band antenna to match. You will find both an adventure. Dave WD9BDZ Article: 224983 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: H FIELD ANTENNAS? Date: Mon, 05 Jun 2006 19:49:05 -0000 Message-ID: <12892lh84m3aeba@corp.supernews.com> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1288uhmljvib979@corp.supernews.com> In article <1288uhmljvib979@corp.supernews.com>, Roy Lewallen wrote: >Any theory that predicts any antenna can produce an H field without an E >field, or that the H field is unusually large beyond a fraction of a >wavelength from an antenna(*), is flawed. So you're free to make up any >theory you like, and it'll be just as accurate. >(*) Or, from a receiving standpoint, that an antenna responds only to an >H field or it responds more strongly to an H field beyond a fraction of >a wavelength from the antenna. Upon a cursory search, it appears to me that "H-field antenna" is probably another (perhaps misleading) term for "small shielded receiving loop". Discussions about the latter do seem to have the requisite amount of lore, mythology, and strenuous disagreements as to just what this sort of antenna does respond to and how it works. -- 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: 224984 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: Give up CB for ham? Date: Mon, 05 Jun 2006 19:54:48 -0000 Message-ID: <1289308tmhg8aee@corp.supernews.com> References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> In article <1149534276.955122.310050@i40g2000cwc.googlegroups.com>, wrote: >Alot of people are telling me that CB is just for inbred hicks and that >I should replace the CB in my truck with a ham radio. What do you >thjink? I think that you asked precisely that same question (modulo one typo) back on May 16th, April 15th, and April 3. I think you have no serious interest in the answers you've received. I think you're acting like a juvenile troll, and therefore receive 0 points on the Troll-o-meter (with a three-point penalty for showing an utter lack of imagination in your trolling). -- 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: 224985 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: J pole question Date: Mon, 5 Jun 2006 16:36:22 -0500 Message-ID: References: This is a multi-part message in MIME format. ------=_NextPart_000_0074_01C688BE.2E754940 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Nope. Only read about it and, perhaps, understand the theory. 73, Steve, K9DCI "Harbin" wrote in message = news:xNKdnePQUp5mlf3Z4p2dnA@adelphia.com... "Steve N." wrote in message = news:e3obpl$bo9$1@avnika.corp.mot.com... Harbin, You seem to understand the "J-Antenna". What you really seem to = be asking is how far apart is "too far" for a balanced transmission = line. That's a question I can't answer and I'm sure others can, but , = in the common custom of adding obtuse references which sort of seem to = be relevant... what about that old one wire transmission like the = "G-Line"? [no joke] 73, Steve, K9DCI Hi Steve: I have read about the G-Line, which is very low loss (so = claimed). Have you heard of anybody that has used this line? ------=_NextPart_000_0074_01C688BE.2E754940 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Nope.  Only read about it and, = perhaps,=20 understand the theory.
73, Steve, K9DCI
 
"Harbin" <harbinjr@adelphia.net> = wrote in=20 message news:xNKdnePQUp5mlf3Z4p= 2dnA@adelphia.com...
"Steve N." <stuevue.nouskuowuic= uz@moutouroula.com>=20 wrote in message news:e3obpl$bo9$1@avnika.c= orp.mot.com...
 
 
 Harbin,
    You seem to = understand the=20 "J-Antenna".  What you really seem to be asking is how far = apart is=20 "too far" for a balanced transmission line.  That's a question = I can't=20 answer and I'm sure others can, but , in the common custom of adding = obtuse=20 references which sort of seem to be relevant... what about that old = one wire=20 transmission  like the "G-Line"?  [no joke]
 
73, Steve, K9DCI
 
 
Hi Steve:
    I have read about the G-Line, which is very = low loss=20 (so claimed). Have
you heard of anybody that has used this=20 line?
------=_NextPart_000_0074_01C688BE.2E754940-- Article: 224986 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: FIGHT! FIGHT! FIGHT! Date: Mon, 5 Jun 2006 16:29:56 -0500 Message-ID: References: <17757-44746714-21@storefull-3257.bay.webtv.net> <1148486661.748365.219740@u72g2000cwu.googlegroups.com> <1149261241.354995.121520@y43g2000cwc.googlegroups.com> wrote in message news:1149261241.354995.121520@y43g2000cwc.googlegroups.com... > Thanks, Steve, > > Good post. Thanks. You do need to read a little more: by mentioning Doppler > shifts, I was illustrating that a linear system can generate new > frequencies without violating the law of superposition. Hi Glenn, I got that. Perhaps my use of "relativitistic effects" was inappropriate. I still maintain that Doppler shift is not an example of (at least what I would call) "creating new frequencies" because an electronis system did not cause said shift. A system is linear or non-linear, but a system can't "make Doppler happen". It is a frequency change, yes, but an "electronic system" can't cause it. It occurs for reasons other than "system characteristics". Yes, a space craft can be considered part of a system in teh general sense, but not as I believe an "electronic system" should be thought of when discussing such things. Perhaps symmantics in your view, but not mine. I think it is a fundamental, but, perhaps can't explain adequately why. What a thread. usually when a thread gets this long it digresses far outside the original intent. > ...Earlier posts were > confusing as the term 'linearity' ...electrical superposition sense >... and ... current distribution along the antenna element. So you *were* questioning the linearity of antennas as we understand the term? 73, Steve > > 73, > Glenn AC7ZN > > > > Steve N. wrote: > > wrote in message > > news:1148486661.748365.219740@u72g2000cwu.googlegroups.com... > > > ...> By the way, generating new frequencies is not necessarily a violation > > > of superposition (though it usually is). Consider a system undergoing > > > a constant Doppler shift. > > > > > > 73, > > > Glenn AC7ZN > > > > > > > Glenn, > > boy! I can't read all these posts, so I was trying to see where you were > > going and asking by just skimming, primarily your posts. > > > > The above caught my eye. Doppler is not "generating new frequencies" as a > > non linearity does. A non-linear system will produce harmonics with one > > exitation frequency and produce the common mixing / IM with multiple > > exitation (superimposed) frequencies. I think trying to mix relativistic > > effects in with the stationary world is an unnecessary complication of a > > linearity discussion. > > If I have time I'll try to follow the thread to see what you're really > > after...but. If it takes mega watts to see some non linearity in an > > antenna, who cares? and more importantly how will you know whree it is > > occuring since things like the junction of two connectorc can produce enough > > IM to mask other, smaller sources. If you tried an experiment looking > > for IM / Mixing you might try to use a receiver becaue a receiver could be a > > very sensitive detector...but you'd have to have a pretty good receiver. > > Something like a kW LO and mixer to have a really good intercept. > > I'm not sure of the point here... Do antennas cause IM? > > Sounds like a deadend arena to me. > > > > 73, Steve, K9DCI > Article: 224987 of rec.radio.amateur.antenna From: Allodoxaphobia Subject: Re: Give up CB for ham? Date: 5 Jun 2006 21:56:12 GMT Message-ID: References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> On 5 Jun 2006 12:04:37 -0700, patk1212@gmail.com wrote: > Alot of people are telling me that CB is just for inbred hicks and that > I should replace the CB in my truck with a ham radio. What do you > thjink? I think it's off topic in an antenna ng. But, then, a usenet troll wouldn't be expected to observe protocol. Article: 224988 of rec.radio.amateur.antenna From: "Woody" References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <1289308tmhg8aee@corp.supernews.com> Subject: Re: Give up CB for ham? Message-ID: Date: Mon, 05 Jun 2006 23:59:18 GMT And a big fat amen to that. rb "Dave Platt" wrote in message news:1289308tmhg8aee@corp.supernews.com... > In article <1149534276.955122.310050@i40g2000cwc.googlegroups.com>, > wrote: > >>Alot of people are telling me that CB is just for inbred hicks and that >>I should replace the CB in my truck with a ham radio. What do you >>thjink? > > I think that you asked precisely that same question (modulo one typo) > back on May 16th, April 15th, and April 3. > > I think you have no serious interest in the answers you've received. > > I think you're acting like a juvenile troll, and therefore receive 0 > points on the Troll-o-meter (with a three-point penalty for showing an > utter lack of imagination in your trolling). > > -- > 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: 224989 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: I was going through about ten years of ham catalogs, and I noticed a disturbing trend. Date: Tue, 06 Jun 2006 00:03:37 -0000 Message-ID: <1289hipia64se92@corp.supernews.com> References: <94Jgg.9081$921.5558@newsread4.news.pas.earthlink.net> >>> A microphone, a six-pack, a karaoke system, & you're a star. :-) >> Yep, see: http://www.qsl.net/w5dxp/w5dxp.jpg >Have to start calling you Slim Whitman. Another definite advantage to CW, I suppose. With SSB there's no telling when you might hear something that could make your head explode. -- 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: 224990 of rec.radio.amateur.antenna Subject: Re: H FIELD ANTENNAS? From: chuck Date: Mon, 05 Jun 2006 21:05:20 -0400 Message-ID: <1149555276_31319@sp6iad.superfeed.net> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> K7ITM wrote: > Are you trying to pull our leg? A google search for "Chelton Loop" > antenna turns up only references to a street, Chelton Loop, in Colorado > Springs. If there's a "Chelton Loop" antenna, it must not have had > much written about it. > > If you want to detect magnetic fields at HF, a small coil of wire > should work well. The size would depend on the size of the magnetic > field you're probing, and the spatial accuracy you want. If you want > to receive electromagnetic signals, as others have posted, be careful > about claims of sensing "only" the H field. > > Cheers, > Tom > > justin.gill@tesco.net wrote: >> Is anyone aware of any sources of information/theory on H Field >> antennas, such as the Chelton Loop for HF? > FWIW, Tom, "chelton" was probably a typo. There is indeed a Chilton Loop Antenna at a research facility in the UK. I think the name refers to the loop used at the Chilton facility, rather than to a particular antenna design. Chuck http://www.ukssdc.ac.uk/ionosondes/chiltonpiccys.html Pictures from the Chilton site ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 224991 of rec.radio.amateur.antenna Date: Mon, 05 Jun 2006 20:37:16 -0500 From: Tom Ring Subject: Re: Give up CB for ham? References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> Message-ID: <4484dc50$0$1013$39cecf19@news.twtelecom.net> patk1212@gmail.com wrote: > Alot of people are telling me that CB is just for inbred hicks and that > I should replace the CB in my truck with a ham radio. What do you > thjink? > You should go for your license. The additional privelages are quite worthwhile. I will warn you that there are still quite a few inbred hicks that got their ham tickets, unfortunately. The good thing is most of them seem to be extra class, and are mostly older and will be gone soon. It's a leftover effect of requiring Morse ability as opposed to operating knowledge. tom K0TAR Article: 224992 of rec.radio.amateur.antenna From: "Cecil Moore" References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> <8HMgg.46032$Lm5.40693@newssvr12.news.prodigy.com> Subject: Re: Choke /BALUN Message-ID: Date: Tue, 06 Jun 2006 02:30:16 GMT "Mike Coslo" wrote: > Outlook Express? Say it ain't so Cecil!! I was running Netscape but Netscape 8.1 doesn't do newsgroups. Someone recommended Thunderbird. Comments? -- 73, Cecil http://www.qsl.net/w5dxp Article: 224993 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Choke /BALUN References: <1149412097.324163.112210@u72g2000cwu.googlegroups.com> <8HMgg.46032$Lm5.40693@newssvr12.news.prodigy.com> <7%5hg.111567$dW3.3280@newssvr21.news.prodigy.com> Message-ID: Date: Tue, 06 Jun 2006 03:34:13 GMT Jim - NN7K wrote: > This reply IS useing Thunderbird (and quite stable, too-- Jim NN7K OK, I just downloaded Thunderbird and it looks pretty good. -- 73, Cecil http://www.qsl.net/w5dxp Article: 224994 of rec.radio.amateur.antenna From: Chris W <1qazse4@cox.net> Subject: sealing coax holes in outside wall Message-ID: Date: Mon, 05 Jun 2006 23:31:07 -0500 Can anyone tell me what the official name of the putty they use to seal the holes you run your coax through so bugs don't crawl in the wall or water doesn't get in? I like to get all my hardware type items from mcmaster.com. I'm sure they have it, if I just know what it is called I can find it on their website. -- Chris W KE5GIX Gift Giving Made Easy Get the gifts you want & give the gifts they want One stop wish list for any gift, >from anywhere, for any occasion! http://thewishzone.com Article: 224995 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: sealing coax holes in outside wall Date: Tue, 06 Jun 2006 04:50:05 -0000 Message-ID: <128a2bt67gcjd4d@corp.supernews.com> References: In article , Chris W <1qazse4@cox.net> wrote: >Can anyone tell me what the official name of the putty they use to seal >the holes you run your coax through so bugs don't crawl in the wall or >water doesn't get in? I like to get all my hardware type items from >mcmaster.com. The box I have here says "One roll RTE62 R-type re-enterable sealing material". RTE62 seems to be a 3M product type. A similar product seems to be Google-able under the term "electrical duct sealant" or "mastic". GB Electrical DS-110 is one type that comes up... about $3/pound in quantity. -- 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: 224996 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Give up CB for ham? Date: Mon, 05 Jun 2006 23:59:38 -0500 Message-ID: <128a2tq2vmeil53@corp.supernews.com> References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> Tom Ring wrote: > patk1212@gmail.com wrote: > >> Alot of people are telling me that CB is just for inbred hicks and that >> I should replace the CB in my truck with a ham radio. What do you >> thjink? >> > > You should go for your license. The additional privelages are quite > worthwhile. I will warn you that there are still quite a few inbred > hicks that got their ham tickets, unfortunately. The good thing is most > of them seem to be extra class, and are mostly older and will be gone > soon. It's a leftover effect of requiring Morse ability as opposed to > operating knowledge. > > tom > K0TAR The problem with the newbys with nocode techs is that they don't realize that knowing the code is just as important as knowing how to press the on/off button. Dave WD9BDZ Article: 224997 of rec.radio.amateur.antenna From: Chris W <1qazse4@cox.net> Subject: Re: sealing coax holes in outside wall References: <128a2bt67gcjd4d@corp.supernews.com> Message-ID: Date: Tue, 06 Jun 2006 00:08:41 -0500 Dave Platt wrote: > "electrical > duct sealant" or "mastic". I have some mastic but I thought that was just for sealing around connectors not to seal the hole the in the wall the coax comes through. -- Chris W KE5GIX Gift Giving Made Easy Get the gifts you want & give the gifts they want One stop wish list for any gift, >from anywhere, for any occasion! http://thewishzone.com Article: 224998 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: FIGHT! FIGHT! FIGHT! Date: Tue, 06 Jun 2006 00:25:50 -0700 Message-ID: <128abg1dlvo96ae@corp.supernews.com> References: <0bpr62pdua5b09mn0cpm1vjsds6fvkinih@4ax.com> <21360-446DFD85-1304@storefull-3257.bay.webtv.net> <12757m7m6v342f0@corp.supernews.com> <1149577012.112304.95720@f6g2000cwb.googlegroups.com> It's not clear to me whether you're proposing an alternative definition for linearity or for superposition. I've never seen superposition defined as other than that the sum of responses to individual excitations be equal to the response to the sum of the excitations -- that's the definition in Pearson & Maler's _Introductory Circuit Analysis_, Van Valkenburg's _Network Analysis_, and the rather old edition of the _IEEE Standard Dictonary of Electrical and Electronic Terms_ I have. Do you have a reference that gives the definition you propose for superposition? If on the other hand the alternative definition is only for linearity, we'd then be faced with the possibility of having a linear (and time-invariant) circuit which doesn't satisfy superposition. That's not a pleasant circumstance to ponder. Roy Lewallen, W7EL K7ITM wrote: > I recall a prof or two arm-waving over that one. However, I think if > you formulate your definition of linearity properly, the transfer > function y=mx+b will still satisfy linearity. Specifically, if the > _response_ is the _change_ that occurs in the output going from x=0 to > x=x1, then the response for x1 is (m*x1+b)-(m*0+b) = m*x1, and of > course for x2, it's m*x2. The response for x=x1+x2 is m*(x1+x2), which > is exactly the sum of the responses for x1 and x2. > > Similarly, for a mixer/LO system with RF input and IF output, if the > mixer is unbalanced and lets LO get through, it is still a linear > system if the change in output when go from zero input to input x1(t) > plus the change in output when you go from zero input to input x2(t) is > equal to the change in output when you go from zero input to input > (x1(t)+x2(t)). > > But note that a mixer/LO system is NOT time invariant, because the > output for x1(t+delta) is in general NOT the same as the output shifted > in time by delta for input x1(t). > > You can most certainly find text books that define linearity > differently than I did above. I find the definition above to be a more > useful one, however, and it seems to be the one generally accepted in > practice, even if it's not stated accurately in words. > > Cheers, > Tom Article: 224999 of rec.radio.amateur.antenna From: "Jimmie D" References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> <1149555276_31319@sp6iad.superfeed.net> <68L5DZFgDThEFAGn@ifwtech.co.uk> Subject: Re: H FIELD ANTENNAS? Message-ID: Date: Tue, 6 Jun 2006 06:15:49 -0400 "Ian White GM3SEK" wrote in message news:68L5DZFgDThEFAGn@ifwtech.co.uk... > chuck wrote: >> >>FWIW, Tom, "chelton" was probably a typo. There is indeed a Chilton Loop >>Antenna at a research facility in the UK. I think the name refers to the >>loop used at the Chilton facility, rather than to a particular antenna >>design. >> > There seem to be two possible kinds of "Chilton loop". > > One is at www.chilton.com, which is a web-controlled SW radio receiver > located in the USA. This is just a loop of wire in some guy's attic. > > The second kind may be related to the ionosondes located at the Rutherford > Appleton Lab, Chilton, UK; and at Port Stanley, Falkland Islands. These do > use crossed loop antennas (as the referenced picture shows)... but in 25 > years living just a few miles down the road, including 12 years of working > right next to RAL and regularly eating lunch with the hams who work there, > I never heard or saw the term "Chilton loop" until yesterday, right here. > > However, I will make some specific inquiries about those loops. > > > Now if you want something really serious to talk about, those RAL/Stanley > ionosondes are being closed down! The scientists who work there are > horrified, because it would pull the plug on a major international source > of daily data, and terminate the world's longest-running continuous > sequence of ionospheric observations: > http://www.wdc.rl.ac.uk/wdcc1/news/closure_notice.html > > (This actually looks like a clumsy political move to shift the running > costs away from the UK science budget and find some other source of > funding, using the threat of closure as a way to get attention. But > suicide bids of this kind can occasionally go wrong...) > > > -- > 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) > http://www.ifwtech.co.uk/g3sek There is a company named Chelton that makes antennas listed on the web. Shows reference to a lot of military stuff. If they are claiming they have an H antenna then............... Article: 225000 of rec.radio.amateur.antenna From: "Brian MW3BAU / 2W0BDW" References: Subject: Re: sealing coax holes in outside wall Message-ID: Date: Tue, 06 Jun 2006 11:44:55 GMT "Chris W" <1qazse4@cox.net> wrote in message news:fy7hg.52579$9c6.12825@dukeread11... > Can anyone tell me what the official name of the putty they use to seal > the holes you run your coax through so bugs don't crawl in the wall or > water doesn't get in? I like to get all my hardware type items from > mcmaster.com. I'm sure they have it, if I just know what it is called I > can find it on their website. > > > > -- > Chris W > KE5GIX I use a silicone based sealant designed for double glazing fitting. It stands up to UV rays and stops bugs, rain etc. Article: 225001 of rec.radio.amateur.antenna From: "John Passaneau" Subject: Re: sealing coax holes in outside wall Date: Tue, 6 Jun 2006 07:49:51 -0400 Message-ID: References: I use the Duct seal. It works well, your can get it off when needed and is the standard stuff for that sort of work around here in the electrical industry. -- John Passaneau, W3JXP State College Pennsylvania jxp16@psu.edu "Brian MW3BAU / 2W0BDW" wrote in message news:XUdhg.8105$qD.5094@newsfe1-gui.ntli.net... > > "Chris W" <1qazse4@cox.net> wrote in message > news:fy7hg.52579$9c6.12825@dukeread11... >> Can anyone tell me what the official name of the putty they use to seal >> the holes you run your coax through so bugs don't crawl in the wall or >> water doesn't get in? I like to get all my hardware type items from >> mcmaster.com. I'm sure they have it, if I just know what it is called I >> can find it on their website. >> >> >> >> -- >> Chris W >> KE5GIX > > I use a silicone based sealant designed for double glazing fitting. It > stands up to UV rays and stops bugs, rain etc. > Article: 225002 of rec.radio.amateur.antenna Date: Tue, 06 Jun 2006 08:16:51 -0400 From: "J. D. B." Subject: Re: Elimination of CW is a loss in the number of ways we can communicate References: <9e847$4482def6$d06640f9$28274@FUSE.NET> <1149441418.531073.162560@j55g2000cwa.googlegroups.com> Message-ID: That is a very good point that I never considered. In thinking about it, it makes perfect sense. "Mode Welfare" - too funny. JDB an old friend wrote: > > the concern is obvious for decades the CW crowd has relied on the > requirement to force all ham to at try it. mode welfare. they are afaid > without that stick the mode will die . it show a lack ocnvednce in the > mode > Article: 225003 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: Give up CB for ham? Date: Tue, 06 Jun 2006 05:18:48 -0700 Message-ID: <5isa8294s7h2n8qtlpe39amh3qna7oa4hk@4ax.com> References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> <128a2tq2vmeil53@corp.supernews.com> ORIGINAL MESSAGE: On Mon, 05 Jun 2006 23:59:38 -0500, "David G. Nagel" wrote: >The problem with the newbys with nocode techs is that they don't realize >that knowing the code is just as important as knowing how to press the >on/off button. > >Dave WD9BDZ *********** REPLY SEPARATOR *********** "Just as important"? Boggles the mind. 73, Bill W6WRT 49 yr ham, Extra Class Article: 225004 of rec.radio.amateur.antenna Message-ID: <448576ab$0$22052$626a54ce@news.free.fr> From: F8BOE Subject: Re: H FIELD ANTENNAS? Date: Tue, 06 Jun 2006 14:35:57 +0200 References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> yes Article: 225005 of rec.radio.amateur.antenna From: "clfe" References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> <128a2tq2vmeil53@corp.supernews.com> <5isa8294s7h2n8qtlpe39amh3qna7oa4hk@4ax.com> Subject: Re: Give up CB for ham? Date: Tue, 6 Jun 2006 09:36:21 -0400 Message-ID: <4485851f$0$3708$ecde5a14@news.coretel.net> "Bill Turner" wrote in message news:5isa8294s7h2n8qtlpe39amh3qna7oa4hk@4ax.com... > ORIGINAL MESSAGE: > > On Mon, 05 Jun 2006 23:59:38 -0500, "David G. Nagel" > wrote: > >>The problem with the newbys with nocode techs is that they don't realize >>that knowing the code is just as important as knowing how to press the >>on/off button. >> >>Dave WD9BDZ > > *********** REPLY SEPARATOR *********** > > "Just as important"? > > Boggles the mind. > > 73, Bill W6WRT > 49 yr ham, Extra Class I don't think you can really expect the newbies to want/desire to know that which they know may be being phased out soon. Why worry about learning it if they know it will soon be gone? I am of the opinion that a 5 WPM at least - should be kept on as a requirement - as someday - it may be needed. Think not? Say you're in the midst of an attack - of terrorism, a war on our homefront OR a large scale natural disaster, a microphone isn't working or available. You can key the radio but don't know code - now what? With code, even at 5 WPM - you could get some very important information to those needing it to help save you - to them. You could tell them WITH code, what is needed, exact whereabouts, how many people involved, etc........ Just clicking a mic pin with a wire won't tell anyone anything and could delay any help or a response big enough to do much good. In these times with the large scale disasters as we've seen and attacks - even for any said to be planned, NOW is a good time to WANT to know code. IT may save you........ It is one of those skills you learn - just like CPR or whatever - you hope you never have to use, but you're glad you have it - when you need it. 5 WPM is NOT hard to learn or do. ANYONE with any interest can learn it in a month at most if you take x amount of characters a day and start using them. Many learn it sooner but it shouldn't take more than a month to get to 5 WPM. "I" know how I learned it but my method won't work for all, just as others didn't work for me. But the main thing is, you must "want" to learn it. If you were 16 and didn't want to learn to drive a car - plain and simple your driving days would be non-existant or very short lived at best- point being MOST 16 year olds WANT to learn to drive. YOU HAVE TO WANT IT. Many of you may have heard of the Quecreek Mine incident in PA some time ago. A pipe was drilled down into the shaft. Those at the surface heard 9 taps on it, signifying there were 9 miners there. NOW - if any of those miners KNEW code, they could have gotten a message to the surface as to what conditions were exactly, the extent of injuries as best they could, etc. Maybe even instructions to help those on the surface plan their moves a tad better. Luckily, the 9 were saved but that is an example of just those 9 taps - crude MORSE - which sent a valid message. Were it not for that, no one would have known they were alive until someone may have went in. AND - MAYBE - those digging operations after a couple hours would have slowed due to lost hope. The fact they knew those guys were still alive gave them urgency to press on......... Code CAN have a place in your life. clfe Article: 225006 of rec.radio.amateur.antenna From: "clfe" References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> <128a2tq2vmeil53@corp.supernews.com> <5isa8294s7h2n8qtlpe39amh3qna7oa4hk@4ax.com> <4485851f$0$3708$ecde5a14@news.coretel.net> Subject: Re: Give up CB for ham? Date: Tue, 6 Jun 2006 09:54:14 -0400 Message-ID: <44858906$0$3702$ecde5a14@news.coretel.net> "clfe" wrote in message news:4485851f$0$3708$ecde5a14@news.coretel.net... > "Bill Turner" wrote in message > news:5isa8294s7h2n8qtlpe39amh3qna7oa4hk@4ax.com... >> ORIGINAL MESSAGE: >> >> On Mon, 05 Jun 2006 23:59:38 -0500, "David G. Nagel" >> wrote: >> >>>The problem with the newbys with nocode techs is that they don't realize >>>that knowing the code is just as important as knowing how to press the >>>on/off button. >>> >>>Dave WD9BDZ >> >> *********** REPLY SEPARATOR *********** >> >> "Just as important"? >> >> Boggles the mind. >> >> 73, Bill W6WRT >> 49 yr ham, Extra Class > > I don't think you can really expect the newbies to want/desire to know > that which they know may be being phased out soon. Why worry about > learning it if they know it will soon be gone? > > I am of the opinion that a 5 WPM at least - should be kept on as a > requirement - as someday - it may be needed. Think not? Say you're in the > midst of an attack - of terrorism, a war on our homefront OR a large scale > natural disaster, a microphone isn't working or available. You can key the > radio but don't know code - now what? With code, even at 5 WPM - you could > get some very important information to those needing it to help save you - > to them. You could tell them WITH code, what is needed, exact whereabouts, > how many people involved, etc........ Just clicking a mic pin with a wire > won't tell anyone anything and could delay any help or a response big > enough to do much good. In these times with the large scale disasters as > we've seen and attacks - even for any said to be planned, NOW is a good > time to WANT to know code. IT may save you........ It is one of those > skills you learn - just like CPR or whatever - you hope you never have to > use, but you're glad you have it - when you need it. > > 5 WPM is NOT hard to learn or do. ANYONE with any interest can learn it in > a month at most if you take x amount of characters a day and start using > them. Many learn it sooner but it shouldn't take more than a month to get > to 5 WPM. "I" know how I learned it but my method won't work for all, just > as others didn't work for me. But the main thing is, you must "want" to > learn it. If you were 16 and didn't want to learn to drive a car - plain > and simple your driving days would be non-existant or very short lived at > best- point being MOST 16 year olds WANT to learn to drive. YOU HAVE TO > WANT IT. > > Many of you may have heard of the Quecreek Mine incident in PA some time > ago. A pipe was drilled down into the shaft. Those at the surface heard 9 > taps on it, signifying there were 9 miners there. NOW - if any of those > miners KNEW code, they could have gotten a message to the surface as to > what conditions were exactly, the extent of injuries as best they could, > etc. Maybe even instructions to help those on the surface plan their moves > a tad better. Luckily, the 9 were saved but that is an example of just > those 9 taps - crude MORSE - which sent a valid message. Were it not for > that, no one would have known they were alive until someone may have went > in. AND - MAYBE - those digging operations after a couple hours would have > slowed due to lost hope. The fact they knew those guys were still alive > gave them urgency to press on......... Code CAN have a place in your life. > > clfe > One other thing........ I cut my teeth on CB back when the FCC was busting CBers regularly for violations. I then got into Ham and Electronics. ALL radio services "CAN" and "DO" have a place when it comes to chatting, information exchange OR emergencies. ALL groups "can" work in unison for the betterment of mankind if desired. Ham has it's place. CB was used mostly by those such as "Auxiliary Police" - where not everyone had to have a "code" much less a license to have studied for - to use radios for their purposes. SEAT-REACT when operated properly was as useful as the Ham groups for emergencies. At one time, I belonged to REACT and some local Ham groups. I'm heavily involved in Public Safety - so I got the best of both worlds. The REACT team died and if I'm not mistaken, maybe the founding unit. Believe me - in a HUGE disaster our fire band was SWAMPED. Ham and CB alike WERE IMPORTANT. I had information on both coming to me - which was of enormous help. I was getting information that was not able to be had via the Fire Radio - due to it being so laden with traffic. I often use FRS radios now too - to avoid tying up the Fire Frequencies here. I USE WHAT I MUST to get the job done. clfe An EMA Coordinator/Firefighter - line officer and former medic - self employed in radio. Article: 225007 of rec.radio.amateur.antenna From: "Bill Ogden" References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> Subject: Re: H FIELD ANTENNAS? Message-ID: Date: Tue, 6 Jun 2006 10:49:15 -0400 OK, let me display my ignorance once again. There are many construction articles about ferrite-core antennas for the low bands. (Not to mention all the ferrite-core antennas in AM receivers.) Are these not H-field antennas, to a large extent? Bill W2WO Article: 225008 of rec.radio.amateur.antenna From: "AAA RF Products" Subject: FS: High Quality Coax Connectors & Adapters at very low prices Message-ID: <%fihg.6120$rS6.5893@fed1read11> Date: Tue, 6 Jun 2006 09:42:39 -0700 Please email sales@aaarfproducts.com or call 949 481 3154 (San Clemente, CA, USA) for a copy of our latest catalog. Article: 225009 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: H FIELD ANTENNAS? Date: Tue, 06 Jun 2006 11:16:16 -0700 Message-ID: <128bhjj6t6a6jb9@corp.supernews.com> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> Bill Ogden wrote: > OK, let me display my ignorance once again. > > There are many construction articles about ferrite-core antennas for the low > bands. (Not to mention all the ferrite-core antennas in AM receivers.) Are > these not H-field antennas, to a large extent? Only very locally, and only to a limited extent. When a signal originates far from an antenna, the response to E and H fields is in the ratio of about 377 ohms, the impedance of free space. This is true for *all antennas*. In other words, all antennas have the same relative E and H response to signals originating far away. Very close to a small loop antenna, response is greater to an H field than E field. It does respond to both, however, as all antennas must. As you get farther away from the antenna, the response to the H field decreases in relation to the E field response. At around an eighth wavelength distance from the antenna, the response to E and H fields are about the same as for a distant source. Beyond about an eighth wavelength, the response to the H field is actually *less* than the response to an E field compared to a source at a great distance. The ratio of E to H field responses then decreases to the distant value as you get farther from the antenna. In summary, the antenna responds more strongly to the H field if the source is within about an eighth of a wavelength from the antenna. Beyond that, it actually responds more strongly to the E field relative to the H field than a short dipole or many other antennas -- you could more properly call it an "E-field antenna" in its response to signals beyond about an eighth wavelength. The difference in relative E and H field response among all antennas becomes negligible at great distances; for antennas which are small in terms of wavelength, the difference becomes negligible beyond about a wavelength. Now, suppose you could make a magic antenna which would respond only to the H field of a signal originating at any distance from the antenna (which is impossible). What advantage would it have over a real antenna? Remember that the E/H ratio of any signal originating very far away is 377 ohms, regardless of what kind of antenna or source it came from. Roy Lewallen, W7EL Article: 225010 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Elimination of CW is a loss in the number of ways we can communicate References: <9e847$4482def6$d06640f9$28274@FUSE.NET> <1149441418.531073.162560@j55g2000cwa.googlegroups.com> Message-ID: Date: Tue, 06 Jun 2006 18:50:19 GMT J. D. B. wrote: > That is a very good point that I never considered. In thinking about it, > it makes perfect sense. "Mode Welfare" - too funny. You could also consider the written exams to be technical knowledge welfare and rules and regulations welfare. -- 73, Cecil http://www.qsl.net/w5dxp Article: 225011 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Give up CB for ham? References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> <128a2tq2vmeil53@corp.supernews.com> <5isa8294s7h2n8qtlpe39amh3qna7oa4hk@4ax.com> <4485851f$0$3708$ecde5a14@news.coretel.net> Message-ID: Date: Tue, 06 Jun 2006 19:01:12 GMT clfe wrote: > Many of you may have heard of the Quecreek Mine incident in PA some time > ago. A pipe was drilled down into the shaft. Those at the surface heard 9 > taps on it, signifying there were 9 miners there. NOW - if any of those > miners KNEW code, they could have gotten a message to the surface as to what > conditions were exactly, the extent of injuries as best they could, etc. Not by tapping. International Morse requires dashes as well as taps (dots). There is a tap code used in prisons that will accomplish communications under those circumstances. And since more people have been in prison than hold an amateur radio license, seems that it would make more sense to require knowing the tap code than to require knowing International Morse code. -- 73, Cecil http://www.qsl.net/w5dxp Article: 225012 of rec.radio.amateur.antenna From: "Steve N." Subject: Re: Grounding a metal roof Date: Tue, 6 Jun 2006 13:59:37 -0500 Message-ID: References: <1148272981_5573@sp6iad.superfeed.net> "Sal M. Onella" wrote in message news:qyPfg.28259$QP4.21821@fed1read12... > > "Steve N." wrote in message > news:e5nbit$5p4$1@avnika.corp.mot.com... > > And so it goes... > > < snip > > > > I was in the Phillipines, uh oh! it's comming back ... NAV COM STA PHIL > > > Likewise. I was a CTMSN/CTM3 there. April 1963 - August 1964. Worked in > the receiver building. I have run into a lot of guys who were there -- all > later than this graybeard. I don't recognize your name, even with the extra > u's taken out. > > John > KD6VKW Lets see... Basic in G.L., A school in Pensacola then I was there...mid 65 to Sept 66. Just "down the road"... CTM3 at the DF site. Names fail me for 90% of the guys... Passed the test & Practical Factors for CTM2, but wouldn't sign up for the full 6 active so I spent the last several monthc fixing typewriters in the receiver bldg instead of going to the site at Cleat AFB. Boo hoo (short timer from day one) There were a couple of Air Force guys still there, but not for long. Do you know about the web site? http://www.usncva.org/ didn't see any recognizable names there. 73, Steve, K9DCI Article: 225013 of rec.radio.amateur.antenna From: "Jimmie D" References: Subject: Re: sealing coax holes in outside wall Message-ID: Date: Tue, 6 Jun 2006 10:00:55 -0400 "Chris W" <1qazse4@cox.net> wrote in message news:fy7hg.52579$9c6.12825@dukeread11... > Can anyone tell me what the official name of the putty they use to seal > the holes you run your coax through so bugs don't crawl in the wall or > water doesn't get in? I like to get all my hardware type items from > mcmaster.com. I'm sure they have it, if I just know what it is called I > can find it on their website. > > > > -- > Chris W > KE5GIX > > Gift Giving Made Easy > Get the gifts you want & > give the gifts they want > One stop wish list for any gift, > from anywhere, for any occasion! > http://thewishzone.com Pull the cable out of the wall from hte outside by a couple of inches, place a good dollop of silicon caulk ( the same stuff you use to caulk around your windows) about an inch or two from the wall then pull the cable back inside. This will make a custom fitted grommet . Dress the cable downward from the hole so water run away from the hole. Think drip loop Article: 225014 of rec.radio.amateur.antenna Subject: Re: H FIELD ANTENNAS? From: chuck Date: Tue, 06 Jun 2006 16:50:05 -0400 Message-ID: <1149626355_40043@sp6iad.superfeed.net> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> <128bhjj6t6a6jb9@corp.supernews.com> Roy Lewallen wrote: > Bill Ogden wrote: >> OK, let me display my ignorance once again. >> >> There are many construction articles about ferrite-core antennas for >> the low >> bands. (Not to mention all the ferrite-core antennas in AM >> receivers.) Are >> these not H-field antennas, to a large extent? > > Only very locally, and only to a limited extent. > > When a signal originates far from an antenna, the response to E and H > fields is in the ratio of about 377 ohms, the impedance of free space. > This is true for *all antennas*. In other words, all antennas have the > same relative E and H response to signals originating far away. > > Very close to a small loop antenna, response is greater to an H field > than E field. It does respond to both, however, as all antennas must. As > you get farther away from the antenna, the response to the H field > decreases in relation to the E field response. At around an eighth > wavelength distance from the antenna, the response to E and H fields are > about the same as for a distant source. Beyond about an eighth > wavelength, the response to the H field is actually *less* than the > response to an E field compared to a source at a great distance. The > ratio of E to H field responses then decreases to the distant value as > you get farther from the antenna. > > In summary, the antenna responds more strongly to the H field if the > source is within about an eighth of a wavelength from the antenna. > Beyond that, it actually responds more strongly to the E field relative > to the H field than a short dipole or many other antennas -- you could > more properly call it an "E-field antenna" in its response to signals > beyond about an eighth wavelength. The difference in relative E and H > field response among all antennas becomes negligible at great distances; > for antennas which are small in terms of wavelength, the difference > becomes negligible beyond about a wavelength. > > Now, suppose you could make a magic antenna which would respond only to > the H field of a signal originating at any distance from the antenna > (which is impossible). What advantage would it have over a real antenna? > Remember that the E/H ratio of any signal originating very far away is > 377 ohms, regardless of what kind of antenna or source it came from. > > Roy Lewallen, W7EL There seems to be a number of commercial antennas described as H-field antennas intended for LORAN application. Most claim improved immunity to precipitation static. Is there a theoretical basis for such claims? Thanks. Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 225015 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: H FIELD ANTENNAS? Date: Tue, 6 Jun 2006 15:46:56 -0500 Message-ID: <23774-4485E9C0-784@storefull-3257.bay.webtv.net> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> Justin Gill wrote: "Is anyone aware of any source of information / theory on H Field antennas, such as Chelton Loop for HF?' Search on H-field antenna. Then click on "Standard H-field NRSC antenna -Chris Scott and Associates. The LP-S series stanard H-field Antenna is specifically designed for emission measurement of AM broadcast stations using a spectrum analyzer or other calibrated receiver. Best regards, Richard Harrison, KB5WZI Article: 225016 of rec.radio.amateur.antenna From: "clfe" References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> <128a2tq2vmeil53@corp.supernews.com> <5isa8294s7h2n8qtlpe39amh3qna7oa4hk@4ax.com> <4485851f$0$3708$ecde5a14@news.coretel.net> Subject: Re: Give up CB for ham? Date: Tue, 6 Jun 2006 17:07:46 -0400 Message-ID: <4485eeaa$0$3704$ecde5a14@news.coretel.net> "Cecil Moore" wrote in message news:Yhkhg.18337$VE1.10294@newssvr14.news.prodigy.com... > clfe wrote: >> Many of you may have heard of the Quecreek Mine incident in PA some time >> ago. A pipe was drilled down into the shaft. Those at the surface heard 9 >> taps on it, signifying there were 9 miners there. NOW - if any of those >> miners KNEW code, they could have gotten a message to the surface as to >> what conditions were exactly, the extent of injuries as best they could, >> etc. > > Not by tapping. International Morse requires dashes as well > as taps (dots). There is a tap code used in prisons that will > accomplish communications under those circumstances. And since > more people have been in prison than hold an amateur radio > license, seems that it would make more sense to require knowing > the tap code than to require knowing International Morse code. > -- > 73, Cecil http://www.qsl.net/w5dxp DUH - I KNOW THAT - I was just saying the tapping let the people at the surface know there were 9 people down there. MORSE CODE - "could" have relayed much more info if one of them knew it. REREAD my message....... I am fully aware of what "code" is, I'm an Extra myself - have been for quite some time. I am also a VE Test Team leader. clfe Article: 225017 of rec.radio.amateur.antenna From: "LLOYD THE LARDASS LOSER DAVIES" References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> Subject: Re: Give up CB for ham? Date: Tue, 6 Jun 2006 18:40:15 -0400 Message-ID: <4485f6e7$0$26775$88260bb3@free.teranews.com> I'm an inbred alabama hick and I hate CB. Lloyd Davies N0VFP Cow Cornholer Nutsackkk Gobbler Dumpster Dweller in Athens, Alabama wrote in message news:1149534276.955122.310050@i40g2000cwc.googlegroups.com... > Alot of people are telling me that CB is just for inbred hicks and that > I should replace the CB in my truck with a ham radio. What do you > thjink? > -- Posted via a free Usenet account from http://www.teranews.com Article: 225018 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: H FIELD ANTENNAS? Date: Tue, 06 Jun 2006 15:46:28 -0700 Message-ID: <128c1e6mscrqe09@corp.supernews.com> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <23774-4485E9C0-784@storefull-3257.bay.webtv.net> Reg Edwards wrote: > > Is this just the usual pseudo-scientific language used by American > antenna salesmen and others? Yes. American antenna salesmen haven't yet gotten as sophisticated as the British inventors and purveyors of the CFA. But they're learning. Be patient -- perhaps someday they'll reach that level. > It all helps to boost sales to the gullible public. Indeed. Roy Lewallen, W7EL Article: 225019 of rec.radio.amateur.antenna From: Jim - NN7K Subject: Re: sealing coax holes in outside wall References: Message-ID: Date: Tue, 06 Jun 2006 23:41:36 GMT Must agree, Duct seal or DUX seal (been a few years) try Greybar, W.W. Grainger, and other parts houses- think couple ##s cost around $5-10 and probably last an individual a lifetime (or take excess to next swap meet, and probably sell it for about what you paid for it!) Jim NN7K John Passaneau wrote: > I use the Duct seal. It works well, your can get it off when needed and is > the standard stuff for that sort of work around here in the electrical > industry. > > Article: 225020 of rec.radio.amateur.antenna From: Jim - NN7K Subject: Re: Jury-rigged SMA connector References: <1149613384.452791.180750@i39g2000cwa.googlegroups.com> Message-ID: Date: Tue, 06 Jun 2006 23:46:42 GMT At- 13.56 GHZ; Probably, at 13.56 Megs, quite doubtful ! NathanielColson@gmail.com wrote: > I'm a UCF student working on an indoor mobile robot positioning system > based on RFID, and I want to connect the SMA cable of a 13.56MHz > single-loop antenna to two pins of a straight-pin header on an RFID > reader. > > My question is, will the characteristics of my antenna be shot to > pieces if I just solder jumpers from the contacts of the coaxial SMA > cable to the two header pins? Is it going to cause noise, interference, > etc. to use those two straight wires for a short distance instead of > the central wire and braided sheath? > Article: 225021 of rec.radio.amateur.antenna Subject: Re: H FIELD ANTENNAS? From: chuck Date: Tue, 06 Jun 2006 20:49:54 -0400 Message-ID: <1149640742_42035@sp6iad.superfeed.net> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> <128bhjj6t6a6jb9@corp.supernews.com> <1149626355_40043@sp6iad.superfeed.net> <1149628313.756125.321140@j55g2000cwa.googlegroups.com> w8ji@akorn.net wrote: >> There seems to be a number of commercial antennas >> described as H-field antennas intended for LORAN >> application. Most claim improved immunity to >> precipitation static. Is there a theoretical basis >> for such claims? > > > Yes. It increases sales just like zoom zoom zoom in car advertisements. > > Seriously, precipitation static is caused by corna discharge from an > antenna or object someplace near the antenna. The radiated field from > that leakage current can be almost any field impedance and will always > be a mixture of time-varying electric and magnetic fields. > > What a small loop actually buys you is a compact antenna that has no > sharp protruding edges, and that decreases the chances of having corona > right from the antenna. A whip would have a sharp protruding point, and > that would encourge corona discharge and the resulting noise we call > "precipitation static". > > Other than that, there is no advantage. > > 73 Tom > I think the precipitation static talked about is caused by the accumulation on the antenna of charges carried by precipitation particles (e.g., snow). Apparently this is a common problem on aircraft antennas, and hence the interest in LORAN antennas with better immunity to the accumulation of precipitation charges. Doesn't sound like a simple antenna geometry issue and it doesn't sound like a corona issue. Which is not to say it isn't all hype, but wouldn't the charge on the antenna simply redistribute itself over the body of the aircraft (assuming it is metal) and not accumulate on the antenna as it would were the antenna insulated >from the aircraft body? Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 225022 of rec.radio.amateur.antenna Date: Tue, 06 Jun 2006 19:58:40 -0500 From: Tom Ring Subject: Re: Give up CB for ham? References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> Message-ID: <448624c0$0$6154$39cecf19@news.twtelecom.net> Tom Ring wrote: > patk1212@gmail.com wrote: > >> Alot of people are telling me that CB is just for inbred hicks and that >> I should replace the CB in my truck with a ham radio. What do you >> thjink? >> > > You should go for your license. The additional privelages are quite > worthwhile. I will warn you that there are still quite a few inbred > hicks that got their ham tickets, unfortunately. The good thing is most > of them seem to be extra class, and are mostly older and will be gone > soon. It's a leftover effect of requiring Morse ability as opposed to > operating knowledge. > > tom > K0TAR Boy it's fun what a little trolling can do to my peers. I'm also an Extra, and licensed for 29 years. Code is worth what it can do, but has had less and less to do with the hobby for decades. It's a great hobby within the hobby on HF, and was the core of EME for years. It still is to some extent, but advances due to moving up in frequency as well as computer based modes as low as 6 and 2 meters are making it something used for EME as much for fun and stubborness as for usefullness. SSB is a very popular mode on EME now among the big guns. CW is dead as far as being needed. It's a great thing to have as a skill, but is now as needed as spark. The person who said they could key an HT to send CW was stretching it way beyond reality. Ain't gonna happen, any more than someone will make a spark transmitter by keying a big bunch of wire they wound in a coil when trapped in their basement by touching it to the hot side of the drop in their fusebox. tom K0TAR Article: 225023 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: sealing coax holes in outside wall Date: Tue, 6 Jun 2006 21:00:58 -0400 Message-ID: <128c98rs98jef8d@corp.supernews.com> References: I too buy from electrical supply house. The stuff also makes a perfect backstop for air-pistol. Comes in one pound blocks. Great stuff. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Jim - NN7K" wrote in message news:Qoohg.46889$Lm5.10653@newssvr12.news.prodigy.com... > Must agree, Duct seal or DUX seal (been a few > years) try Greybar, W.W. Grainger, and other > parts houses- think couple ##s cost around $5-10 > and probably last an individual a lifetime > (or take excess to next swap meet, and probably > sell it for about what you paid for it!) > Jim NN7K > > > John Passaneau wrote: > > I use the Duct seal. It works well, your can get it off when needed and is > > the standard stuff for that sort of work around here in the electrical > > industry. > > > > Article: 225024 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: FIGHT! FIGHT! FIGHT! Date: Tue, 6 Jun 2006 19:57:20 -0500 Message-ID: <23774-44862470-817@storefull-3257.bay.webtv.net> References: <1149609129.041873.312040@g10g2000cwb.googlegroups.com> K7ITM wrote: "If you say that in the system (y = mx + b) that b is the response to zero input (x=0) then you will conclude the system is nonlinear." Why? the factor (b) is a constant, a value to be added to (mx) to total a value for (y). (mx) is a straight line. Every value of (b) produces a straight lline parallel with lhe line y=mx when b=0. Factor (b) is merely the offset value of the sloped line in the x direction. y=mx+b is listed in math books as a defining example of a linear equation. (When plotted, a linear equation produces a straight line.) y=mx+b has a special name: "The point slope formula". Perfectly descriptive, too. To clarify everything, graph a few values for yourself. Best regards, Richard Harrison, KB5WZI Article: 225025 of rec.radio.amateur.antenna From: "clfe" References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> <448624c0$0$6154$39cecf19@news.twtelecom.net> Subject: Re: Give up CB for ham? Date: Tue, 6 Jun 2006 21:15:47 -0400 Message-ID: <448628bb$0$3693$ecde5a14@news.coretel.net> "Tom Ring" wrote in message news:448624c0$0$6154$39cecf19@news.twtelecom.net... > Tom Ring wrote: > >> patk1212@gmail.com wrote: >> >>> Alot of people are telling me that CB is just for inbred hicks and that >>> I should replace the CB in my truck with a ham radio. What do you >>> thjink? >>> >> >> You should go for your license. The additional privelages are quite >> worthwhile. I will warn you that there are still quite a few inbred >> hicks that got their ham tickets, unfortunately. The good thing is most >> of them seem to be extra class, and are mostly older and will be gone >> soon. It's a leftover effect of requiring Morse ability as opposed to >> operating knowledge. >> >> tom >> K0TAR > > Boy it's fun what a little trolling can do to my peers. I'm also an > Extra, and licensed for 29 years. > > Code is worth what it can do, but has had less and less to do with the > hobby for decades. It's a great hobby within the hobby on HF, and was the > core of EME for years. It still is to some extent, but advances due to > moving up in frequency as well as computer based modes as low as 6 and 2 > meters are making it something used for EME as much for fun and > stubborness as for usefullness. SSB is a very popular mode on EME now > among the big guns. > > CW is dead as far as being needed. It's a great thing to have as a skill, > but is now as needed as spark. > > The person who said they could key an HT to send CW was stretching it way > beyond reality. Ain't gonna happen, any more than someone will make a > spark transmitter by keying a big bunch of wire they wound in a coil when > trapped in their basement by touching it to the hot side of the drop in > their fusebox. > > tom > K0TAR I'm not sure if you're referring to my post or someone else's who I didn't see. In "my" example - I was saying if a MIC was broken and they knew code, they could short out the tranmit pins - like making and breaking contact such as a key would do - to broadcast a coded message. It "can" be done. There is what is/was known as "Modulated CW". And, I've seen guys key an H.T. OR Mic and do code with an "Oscillator" with the other hand - thereby transmitting the code - from the Oscillator speaker through the mic of the H.T or radio. Maybe that is what "they" were referring to - I don't know. clfe Article: 225026 of rec.radio.amateur.antenna From: "clfe" References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> <4484dc50$0$1013$39cecf19@news.twtelecom.net> <448624c0$0$6154$39cecf19@news.twtelecom.net> <448628bb$0$3693$ecde5a14@news.coretel.net> Subject: Re: Give up CB for ham? Date: Tue, 6 Jun 2006 21:22:08 -0400 Message-ID: <44862a38$0$3707$ecde5a14@news.coretel.net> "clfe" wrote in message news:448628bb$0$3693$ecde5a14@news.coretel.net... > > "Tom Ring" wrote in message > news:448624c0$0$6154$39cecf19@news.twtelecom.net... >> Tom Ring wrote: >> >>> patk1212@gmail.com wrote: >>> >>>> Alot of people are telling me that CB is just for inbred hicks and that >>>> I should replace the CB in my truck with a ham radio. What do you >>>> thjink? >>>> >>> >>> You should go for your license. The additional privelages are quite >>> worthwhile. I will warn you that there are still quite a few inbred >>> hicks that got their ham tickets, unfortunately. The good thing is most >>> of them seem to be extra class, and are mostly older and will be gone >>> soon. It's a leftover effect of requiring Morse ability as opposed to >>> operating knowledge. >>> >>> tom >>> K0TAR >> >> Boy it's fun what a little trolling can do to my peers. I'm also an >> Extra, and licensed for 29 years. >> >> Code is worth what it can do, but has had less and less to do with the >> hobby for decades. It's a great hobby within the hobby on HF, and was >> the core of EME for years. It still is to some extent, but advances due >> to moving up in frequency as well as computer based modes as low as 6 and >> 2 meters are making it something used for EME as much for fun and >> stubborness as for usefullness. SSB is a very popular mode on EME now >> among the big guns. >> >> CW is dead as far as being needed. It's a great thing to have as a >> skill, but is now as needed as spark. >> >> The person who said they could key an HT to send CW was stretching it way >> beyond reality. Ain't gonna happen, any more than someone will make a >> spark transmitter by keying a big bunch of wire they wound in a coil when >> trapped in their basement by touching it to the hot side of the drop in >> their fusebox. >> >> tom >> K0TAR > > I'm not sure if you're referring to my post or someone else's who I didn't > see. In "my" example - I was saying if a MIC was broken and they knew > code, they could short out the tranmit pins - like making and breaking > contact such as a key would do - to broadcast a coded message. It "can" be > done. There is what is/was known as "Modulated CW". And, I've seen guys > key an H.T. OR Mic and do code with an "Oscillator" with the other hand - > thereby transmitting the code - from the Oscillator speaker through the > mic of the H.T or radio. Maybe that is what "they" were referring to - I > don't know. > > > clfe > Then too along with the above - they "could" have been referring to using the "key pad" to send code while the H.T. was keyed OR using the keypad on a mic while it was keyed......... If memory serves me correct - at the moment (slips at times) - THAT would be equivalent to MCW (Modulated CW). I've seen that done too. clfe Article: 225027 of rec.radio.amateur.antenna From: Butch Magee Subject: Re: Give up CB for ham? Date: Tue, 06 Jun 2006 20:26:27 -0500 Message-ID: <128caq5cknv6vee@corp.supernews.com> References: <1149534276.955122.310050@i40g2000cwc.googlegroups.com> patk1212@gmail.com wrote: > Alot of people are telling me that CB is just for inbred hicks and that > I should replace the CB in my truck with a ham radio. What do you > thjink? > Dont you fall for these dastardly lies. You stay right where you are. Trust me you do not want to be where we are, in 50 or so years you will thank us for keeping you in cbland. Butch Article: 225028 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> <128bhjj6t6a6jb9@corp.supernews.com> Subject: Re: H FIELD ANTENNAS? Message-ID: Date: Tue, 6 Jun 2006 21:28:18 -0400 "Roy Lewallen" wrote > > Very close to a small loop antenna, response is greater to an H field than > E field. It does respond to both, however, as all antennas must. As you > get farther away from the antenna, the response to the H field decreases > in relation to the E field response. At around an eighth wavelength > distance from the antenna, the response to E and H fields are about the > same as for a distant source. Beyond about an eighth wavelength, the > response to the H field is actually *less* than the response to an E field > compared to a source at a great distance. The ratio of E to H field > responses then decreases to the distant value as you get farther from the > antenna. > > In summary, the antenna responds more strongly to the H field if the > source is within about an eighth of a wavelength from the antenna. Beyond > that, it actually responds more strongly to the E field relative to the H > field than a short dipole or many other antennas -- you could more > properly call it an "E-field antenna" in its response to signals beyond > about an eighth wavelength. The difference in relative E and H field > response among all antennas becomes negligible at great distances; for > antennas which are small in terms of wavelength, the difference becomes > negligible beyond about a wavelength. > But according to W8JI "teachings" there is no way that electrostatic shield on a small loop antenna would work as a shield, attenuating E field dominant signals or noise generated within that 1/8 or about wavelength. According to him, it works as an antenna. Some scientwists can not comprehend that electrostatic shield shunts the predominantly E field generated in the vicinity. It is the FACT, easily observable by anyone building shielded small loop and having TV birdies, PS bricks or arcing noise source within about 1/8 of a wavelength. W8JI wrote: >>Seriously, precipitation static is caused by corna discharge from an antenna or object someplace near the antenna. The radiated field from that leakage current can be almost any field impedance and will always be a mixture of time-varying electric and magnetic fields.<< Roy, 'splain to him about this 1/8 or so thing. He still dungetit. 73 Yuri, K3BU Article: 225029 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: H FIELD ANTENNAS? Date: Tue, 06 Jun 2006 18:59:11 -0700 Message-ID: <128ccnil05e0744@corp.supernews.com> References: <1149531001.503023.220830@g10g2000cwb.googlegroups.com> <1149542340.997313.268380@h76g2000cwa.googlegroups.com> <128bhjj6t6a6jb9@corp.supernews.com> Yuri Blanarovich wrote: > . . . > Roy, 'splain to him about this 1/8 or so thing. He still dungetit. Tom understands it, but I see you don't quite have a handle on it yet. Roy Lewallen, W7EL