Article: 219104 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: AM Commercial radio reception Date: Mon, 7 Nov 2005 07:24:19 +0000 (UTC) Message-ID: References: <6487-436C4D06-493@storefull-3252.bay.webtv.net> <436d6a27_3@news1.prserv.net> "Crazy George" wrote > I'm afraid you're way behind the practice on this one. In the US, there are > many 4, 5 and 6 tower arrays providing as many nulls to protect co-channel stations. ================================= What proportion of US MF broadcasting stations have antennas consisting of more than two towers ? ---- Reg. Article: 219105 of rec.radio.amateur.antenna From: "Bill" References: Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Message-ID: Date: Mon, 7 Nov 2005 07:12:20 -0500 Interesting....if there is something better out there what is it?......been using a 259 since "98" and its done the job for me from beams-wires...co-ax measurement....ans the latest, balancing out the 1/4 wave stubs on a Hygain HighTower, as I added 17 meters to the array!! "John Ferrell" wrote in message news:d9enm19a9t3o05d9rd922tls1oq69vptn2@4ax.com... >I am considering ordering the MFJ-269 HF/VHF/UHF Antenna/SWR/RF > Analyzer. > > It sounds like a Swiss Army knife device and I should be able to send > a lot of old equipment to Ebay. Does anyone have any comments to make > on it? Good or bad? > > I have read the review in May 2005 QST and the manual available at > their website. > > John Ferrell, W8CCW Article: 219106 of rec.radio.amateur.antenna From: "John, N9JG" References: Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Message-ID: Date: Mon, 07 Nov 2005 13:46:25 GMT The Palstar ZM30 Digital Antenna Z Bridge - VFO is also an excellent unit. http://www.palstar.com/zm30.php http://www.eham.net/reviews/detail/4782 John, N9JG "Bill" wrote in message news:ruHbf.2405$fB2.2143@bignews2.bellsouth.net... > Interesting....if there is something better out there what is > it?......been using a 259 since "98" and its done the job for me > from beams-wires...co-ax measurement....ans the latest, balancing > out the 1/4 wave stubs on a Hygain HighTower, as I added 17 meters > to the array!! > "John Ferrell" wrote in message > news:d9enm19a9t3o05d9rd922tls1oq69vptn2@4ax.com... >>I am considering ordering the MFJ-269 HF/VHF/UHF Antenna/SWR/RF >> Analyzer. >> >> It sounds like a Swiss Army knife device and I should be able to >> send >> a lot of old equipment to Ebay. Does anyone have any comments to >> make >> on it? Good or bad? >> >> I have read the review in May 2005 QST and the manual available at >> their website. >> >> John Ferrell, W8CCW > > Article: 219107 of rec.radio.amateur.antenna From: "John Passaneau" Subject: Re: how to combat noise? Date: Mon, 7 Nov 2005 09:11:44 -0500 Message-ID: References: <1131365048.980502.250150@z14g2000cwz.googlegroups.com> I use 2 ham stick mobile antennas phased to produce a receive antenna on 80m that works very well. It has a response that is close to a reasonable sized beverage. They are spaced 1/8 wavelength apart and feed 135 deg. out of phase with a coax phasing line. I have a relay setup that lets me change the direction, in my case north-east / south-west. The signal levels are down from the dipole I use for transmit but the signal to noise level are much better. A signal that would be S-9 with S-8 of noise on my dipole becomes S-6 to S-7 on the verticals with no noise. It makes DXing on 80m fun. Details for the design of the phasing system are in ON4UN's book on low band dxing. One of the advantages of using mobile antennas is the mutual coupling is very low between them. This greatly simplifies the setup. Note that this would be a poor transmitting antenna do to the poor ground plane I have and mobile whips are not a good antenna on 80m. -- John Passaneau, W3JXP Penn State University w3jxp@arrl.net "andy" wrote in message news:1131365048.980502.250150@z14g2000cwz.googlegroups.com... > Here is the situation: have an inverted V for 80m and noise level is > S9.. Not good really.... > I did the next logical step and tryied magnetic loop for 80, reciving > only, indoors. That antenna failed awfully.... Noise was S8 but I could > not hear stations that were 9+10 on inverted V. Did'nt matter how I > tryied to rotate the loop, all there was is noise. So, indoors is right > out.. > All that is left is roof. And that makes my situation interesting. It > is a big house with new metal roof, electrically bounded. 10X60 metres, > 17 metres hight, angled about 20 degrees. Big ground plane indeed. All > I could figure is to get some sort of antenna to the roof so the roof > would act as a shield from all the noise generated inside the house. > That antenna would be for receiving 80m, can be narrow band (50KHz > ok). NVIS pattern would be prefered. > So, I have huge ground plane, lots and lots of noise below it, and need > a receiving-only antenna. > What would you do in this situation? Loop, magnetic loop, dipole, short > beverage perhaps??? > Any advice is welcome. Right now I cant even figure if that roof is > acting like a shield or a big noise-sucking antenna.. > > Andrus > Article: 219108 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Message-ID: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> References: Date: Mon, 07 Nov 2005 14:21:59 GMT After reading the remarks here and researching the past posts to the newsgroup on the MFJ-269 I feel I have been missing out on a lot. The best overall description I have found anywhere (including the MFJ web site) is in the current ad in QST. I ordered it Saturday morning and am eagerly awaiting its arrival. John Ferrell, W8CCW On Mon, 7 Nov 2005 07:12:20 -0500, "Bill" wrote: >Interesting....if there is something better out there what is it?......been >using a 259 since "98" and its done the job for me from beams-wires...co-ax >measurement....ans the latest, balancing out the 1/4 wave stubs on a Hygain >HighTower, as I added 17 meters to the array!! > Article: 219109 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: 135' flattop Message-ID: <16pum1d23nfpo0fk38ptisqhkek4gdhte1@4ax.com> References: <4srsm1hkm37tbakooehau801uph9fmctsf@4ax.com> Date: Mon, 07 Nov 2005 14:29:45 GMT Here is a bit I ran across the other day... I copied this out of the MFJ-269 antenna analyzer manual: "Resonance at the feedpoint only repeats when a mismatched feedline is an exact multiple of 1/4 wl. If the line is not an exact multiple of 1/4 wl, the resonant frequency of the antenna might be shifted higher or lower by the transmission line. A mismatched line that is not an exact multiple of a quarter-wavelength adds reactance that can either cancel antenna reactance at frequencies where the antenna is not resonant, or add reactance at frequencies where the antenna is resonant." My deduction: In essence, if the feedline is matched there is no problem. If it is a multiple of 1/4 wave in length there is still no problem! Trying to do both is a good idea. John Ferrell, W8CCW On Sun, 06 Nov 2005 13:07:14 -0800, Dan Richardson <> wrote: >On Sun, 6 Nov 2005 15:43:14 -0500, "garigue" >wrote: > >>Hello all ....I have seen some where a list of what length of feedline to >>avoid resonance wise....... Does anyone know the site ?? I will be >>using 450 twin for the antenna .....never used open wire feed in my 40 years >>in this endeavor. Thanks in advance ...... >> >You need only the length of line necessary to make from you rig/tuner >to the antenna. The are some cases that the line length may result >difficulty matching. If so, just add a few feet. Don't worry about >resonance. > >73, >Danny, K6MHE > >email: k6mhearrlnet >http://www.k6mhe.com/ Article: 219110 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: how to combat noise? Date: Mon, 7 Nov 2005 08:57:52 -0600 Message-ID: <10021-436F6B70-911@storefull-3251.bay.webtv.net> References: <1131365048.980502.250150@z14g2000cwz.googlegroups.com> Andrus wrote: "Any advice is welcome." Andrus has a bonded metal roof 10x60 mtr which is 17 mtr high. An automobile contains radio noise within its engine compartment by using a metal cover. A roof does not completely cover and surround noise sources within a house, but if it is effectively grounded at the receiving frequency, the roof can help block transmission of noise into an antenna mounted above it. A dipole is balanced and slightly directional. This helps avoid noise pick up. A balun at the antenna feedpoint helps keep the antenna balanced and allows connection of coax to run through noisy areas without pickup. A low dipole over a reflective surface has a high-angle radiation pattern, excellent for NVIS. With an agile antenna tuner you may be able to hear and work stations within several hundred miles. Best regards, Richard Harrison, KB5WZI Article: 219111 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: how to combat noise? References: <1131365048.980502.250150@z14g2000cwz.googlegroups.com> Message-ID: Date: Mon, 07 Nov 2005 15:11:24 GMT andy wrote: > Here is the situation: have an inverted V for 80m and noise level is > S9.. Not good really.... > Any advice is welcome. Right now I cant even figure if that roof is > acting like a shield or a big noise-sucking antenna.. If you can somehow get your inverted-V to a horizontal position for testing, you might be plesantly surprised. At my QTH, going >from an inverted-V to a horizontal dipole at the same center height lowered my noise level by 2 S-units on 40m. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219112 of rec.radio.amateur.antenna From: Registered User Subject: Re: What Would You Do?? Date: Mon, 07 Nov 2005 10:01:59 -0500 Message-ID: References: <89xbf.14860$td.1301@bignews3.bellsouth.net> On Sun, 6 Nov 2005 19:27:00 -0500, "Bill" wrote: > > >Years ago I cleared a 200 foot path in among some hard woods....Needed to >practice my high irons.... > Don't we all? I've been using 21 and 24 degree rescue clubs keeping the 3 thru 5 irons in the bag. >But Now...lets put up a monster antenna.. For high bands 17 - 20 meters. > >In this path I've got two 120 foot towers in line with Europe. The towers >are 500 feet apart......Its pretty well open on the sides > >I can easily run a cable between them and then >hang what...??? > >Give me your dream antenna...or your best shot!!! > I would go with a simple 'Loop Skywire' in the vertical plane. A 200x100 foot loop is well over a full-wave at 160M so with a balanced matching device it will be an all-band antenna. I have a 500 foot horizontal loop that provides absolutely amazing performance so I may be a little biased . I would also consider a four bay 40M or a ten bay 20M Sterba curtain. A bobtail curtain is another possibility. 73 de n4jvp Fritz Article: 219113 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: 135' flattop References: <4srsm1hkm37tbakooehau801uph9fmctsf@4ax.com> <16pum1d23nfpo0fk38ptisqhkek4gdhte1@4ax.com> Message-ID: Date: Mon, 07 Nov 2005 15:33:54 GMT John Ferrell wrote: > Here is a bit I ran across the other day... > > I copied this out of the MFJ-269 antenna analyzer manual: > "Resonance at the feedpoint only repeats when a mismatched feedline is > an exact multiple of 1/4 wl. If the line is not an exact multiple of > 1/4 wl, the resonant frequency of the antenna might be shifted higher > or lower by the transmission line. A mismatched line that is not an > exact multiple of a quarter-wavelength adds reactance that can either > cancel antenna reactance at frequencies where the antenna is not > resonant, or add reactance at frequencies where the antenna is > resonant." > > My deduction: > > In essence, if the feedline is matched there is no problem. If it is a > multiple of 1/4 wave in length there is still no problem! Trying to do > both is a good idea. Your deduction is not 100% valid. 1/4WL can be a BIG problem and worst case for matching. I guess MFJ is technically correct but confusing. For instance, assume a 50 ohm antenna and 1/4WL of 600 ohm open-wire line. The "resonant" impedance seen looking into the feedline would be 7200 ohms, outside the matching range for a lot of MFJ tuners. Half a century ago, we called that the "anti-resonant" point (akin to a parallel resonant impedance). Most amateur radio operators should substitute 1/2WL for 1/4WL in the above MFJ manual quote to avoid thinking 1/4WL is "no problem". -- 73, Cecil http://www.qsl.net/w5dxp Article: 219114 of rec.radio.amateur.antenna From: "Denton" Subject: Re: how to combat noise? Date: Mon, 7 Nov 2005 07:34:18 -0800 Message-ID: <11mut03pv2cl0a0@corp.supernews.com> References: <1131365048.980502.250150@z14g2000cwz.googlegroups.com> A couple of antennas that work well at this qth...typical urban environment with elevated power lines and assorted other racket. Run a big horizontal loop around the place..feed with coax for recieve only or twin lead plus transmatch for recieve/transmit. This is the one I am currently using. Previous antenna...which also works pretty good was a 100 ft bowtie doublet. I used to run the doublet with vertical drops on the ends, but found that any vertical drop on the ends of the antenna really picked up the racket. If I left the vertical drops off the ends, I never did like the way the Johnson Matchbox was coupling with the feedline...450 ohm...on 80 meters. I would up with 10 ft end drops, then running a wire from the bottom of the end drops back up to the feed point. Tuned a lot better, broad banded and rejected noise pretty well. "andy" wrote in message news:1131365048.980502.250150@z14g2000cwz.googlegroups.com... > Here is the situation: have an inverted V for 80m and noise level is > S9.. Not good really.... > I did the next logical step and tryied magnetic loop for 80, reciving > only, indoors. That antenna failed awfully.... Noise was S8 but I could > not hear stations that were 9+10 on inverted V. Did'nt matter how I > tryied to rotate the loop, all there was is noise. So, indoors is right > out.. > All that is left is roof. And that makes my situation interesting. It > is a big house with new metal roof, electrically bounded. 10X60 metres, > 17 metres hight, angled about 20 degrees. Big ground plane indeed. All > I could figure is to get some sort of antenna to the roof so the roof > would act as a shield from all the noise generated inside the house. > That antenna would be for receiving 80m, can be narrow band (50KHz > ok). NVIS pattern would be prefered. > So, I have huge ground plane, lots and lots of noise below it, and need > a receiving-only antenna. > What would you do in this situation? Loop, magnetic loop, dipole, short > beverage perhaps??? > Any advice is welcome. Right now I cant even figure if that roof is > acting like a shield or a big noise-sucking antenna.. > > Andrus > Article: 219115 of rec.radio.amateur.antenna From: "RST Engineering" Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Date: Mon, 7 Nov 2005 07:52:26 -0800 Message-ID: <11muu2etf24fe00@corp.supernews.com> References: The only problem with the Palstar is that it only goes to 30 MHz., while the MFJ goes well into the VHF range past two meters with (I believe) an option to go to 440. Jim "John, N9JG" wrote in message news:RUIbf.527814$_o.286485@attbi_s71... > The Palstar ZM30 Digital Antenna Z Bridge - VFO is also an excellent unit. Article: 219116 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: how to combat noise? References: <1131365048.980502.250150@z14g2000cwz.googlegroups.com> <11mut03pv2cl0a0@corp.supernews.com> Message-ID: Date: Mon, 07 Nov 2005 16:01:51 GMT Denton wrote: > I used to run the doublet with vertical drops on the ends, but found that > any vertical drop on the ends of the antenna really picked up the racket. Same as at my QTH. Anything vertical is noisier on receive. > If I left the vertical drops off the ends, I never did like the way the Johnson > Matchbox was coupling with the feedline...450 ohm...on 80 meters. Because your feedline length was somewhere in the ballpark of 1/4 wavelength and presented a very high impedance to the Matchbox. Ladder-line feedline lengths for low-impedance antennas need so be close to multiples of 1/2 wavelength, a little over 100 feet on 80m. Unfortunately, a lot of ladder-line-fed 80m dipoles and loops are closer to 1/4WL, around 60 feet or so which may be worst case for limited range tuners like Johnson Matchboxes and internal autotuners. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219117 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Flagpole antenna - experiences References: Message-ID: <%3Lbf.10179$D13.8908@newssvr11.news.prodigy.com> Date: Mon, 07 Nov 2005 16:14:51 GMT Mike Bates wrote: > I am considering buying or building a flagpole antenna. My preference > is for an antenna that covers 10 to 80 meters. I have seen the one > listed at the Force-12 site but would like some independent input on > this antenna before buying. Also, I was looking for plans on building > one myself but not much luck yet in finding any. I had one at my QTH but it was so noisey I took it down. Your QTH might have a lower vertically-polarized noise level so here is what I did - not exactly a flagpole but may give you an idea. I erected a 20 foot long vertical fed at the base with an SGC-230 autotuner. It had 8 33 foot buried radials. 20 feet is 5/8WL on 10m. This antenna worked well for transmitting on 40m-10m. If it hadn't been so noisey on receive, I would have added a high-Q base-loading coil for 75m operation although the SGC-230 actually loaded well on 75m. I should have left it up and switched to my dipole for receive. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219118 of rec.radio.amateur.antenna From: "Caveat Lector" References: Subject: Re: Flagpole antenna - experiences Message-ID: Date: Mon, 7 Nov 2005 08:43:22 -0800 A flagpole antenna article at URL: http://www.sgcworld.com/23ftflagpoleinstall.html Uses a SGC tuner Be careful of using PVC pipe -- smaller diameters bend very easy. Also when using PVC, check the PVC grade for carbon content -- some have enough carbon to upset the resonance points. Had a friend put a commercial vertical in PVC pipe but the carbon in the PVC pipe detuned it and it wouldn't work. Building a single band flagpole vertical is easy. But making it cover 80 thru 10M can be complex. You probably want to use a tuner of some kind My 2 cents -- CL -- I doubt, therefore I might be ! "Mike Bates" wrote in message news:NvKdnfyxRdV95fLeRVn-pw@comcast.com... >I am considering buying or building a flagpole antenna. My preference > is for an antenna that covers 10 to 80 meters. I have seen the one > listed at the Force-12 site but would like some independent input on > this antenna before buying. Also, I was looking for plans on building > one myself but not much luck yet in finding any. > > Thanks > Mike > N7DQ Article: 219119 of rec.radio.amateur.antenna From: "RB" Subject: ladderline to coax adapter Message-ID: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Date: Mon, 7 Nov 2005 12:07:30 -0600 Got a Radio Works choke balun I'd like to use for feeding ladderline out of an unbalanced tuner. The balun has coax fittings on each end. Ladderline doesn't adapt well to coax interfaces. What's the best way to put ladderline to my balun coax fitting? I can kluge a PL-259 plug onto the ladderline. I guess I could also stick one side of the ladderline in the center hole of the chassis coac fitting, and clamp the other side to the threaded part of the chassis fitting. Ideas solicited. Article: 219120 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: AM Commercial radio reception Date: Mon, 7 Nov 2005 12:23:03 -0600 Message-ID: <5587-436F9B87-955@storefull-3256.bay.webtv.net> References: Reg, G4FGQ wrote: "What proportions of U.S. broadcasting stations have antennas consisting of more than two towers?" I don`t know but from my own experience, the number is large. A new applicant for a station must show he will not interfere with existing stations by limiting his radiation in the directions of the existing stations while providing minimum field intensity, 0.5 to 50 mV, depending on population, in the new service area. A two-tower array cannot satisfy some complicated pattern requirements. Most broadcasters want to provide more than 1 KW radiation in their areas. Well over one hundred channels in the medium wave broadcast band in North America allow that. There are well over 1000 regional medium wave broadcasters in North America. It is difficult to fit a new broadcaster in when he wants to use real power. Best regards, Richard Harrison, KB5WZI Article: 219121 of rec.radio.amateur.antenna Subject: Re: ladderline to coax adapter From: Ed References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Message-ID: Date: Mon, 07 Nov 2005 18:37:57 GMT > Got a Radio Works choke balun I'd like to use for feeding ladderline > out of an unbalanced tuner. > I'm sure others here will correct me if I'm wrong, but I believe that what you want to do is a very bad idea. Baluns are not meant to operate under the potential very high SWR conditions you are likely to have on the output of your tuner. Damage to the balun is likely. Besides, what is the point of a balun on your tuner's output if you are using ladderline, anyway? Ed K7AAT Article: 219122 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: 135' flattop Message-ID: References: <4srsm1hkm37tbakooehau801uph9fmctsf@4ax.com> <16pum1d23nfpo0fk38ptisqhkek4gdhte1@4ax.com> Date: Mon, 07 Nov 2005 19:07:36 GMT That makes sense to me! Thanks for the correction. A bold but incorrect position frequently provokes some one who knows to reveal the correct answers... On Mon, 07 Nov 2005 15:33:54 GMT, Cecil Moore wrote: John Ferrell W8CCW >Your deduction is not 100% valid. 1/4WL can be a BIG problem and >worst case for matching. > >I guess MFJ is technically correct but confusing. For instance, >assume a 50 ohm antenna and 1/4WL of 600 ohm open-wire line. The >"resonant" impedance seen looking into the feedline would be 7200 >ohms, outside the matching range for a lot of MFJ tuners. Half a >century ago, we called that the "anti-resonant" point (akin to a >parallel resonant impedance). Most amateur radio operators should >substitute 1/2WL for 1/4WL in the above MFJ manual quote to avoid >thinking 1/4WL is "no problem". Article: 219123 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: Antenna gain question Date: Mon, 07 Nov 2005 11:16:08 -0800 Message-ID: References: Richard Clark wrote: >> EZNEC+ ver. 4.0 >> >>Dipole in Ring of Sources 11/2/2005 10:00:48 PM >> >> --------------- LOAD DATA --------------- >> >>Frequency = 70 MHz >> >>Load 1 Voltage = 4.783 V. at 23.52 deg. >> Current = 0.06643 A. at 23.52 deg. >> Impedance = 72 + J 0 ohms >> Power = 0.3177 watts >> >> Total applied power = 2000 watts >> >> Total load power = 0.3177 watts > > > Taking the determination above as the "standard" I then have > progressed to place an NBS yagi in three space about the center to > obtain its best result. > > All such expressions (x,y,z) of the placement of the NBS yagi are with > respect to its "driven" element. > > 0,0,0 Power = 0.2091 watts > .5,0,0 Power = 0.2198 watts > 1,0,0 Power = 0.1429 watts > 1.5,0,0 Power = 0.1026 watts > 2,0,0 Power = 0.1601 watts > 2.5,0,0 Power = 0.2113 watts > 3,0,0 Power = 0.1571 watts > 3.5,0,0 Power = 0.06028 watts > 4,0,0 Power = 0.04128 watts > > So, within one quadrant, and over the space of roughly a wavelength, > and at intervals of roughly one eighth wavelength, nothing emerges as > being equal to the "standard" above. Except perhaps a hidden peak > between 0,0,0 and .5,0,0. To investigate this: > .25,0,0 Power = 0.2286 watts > examining further: > .125,0,0 Power = 0.2219 watts > nope, examining further: > .375,0,0 Power = 0.2278 watts > nope, examining further: > .30,0,0 Power = 0.2291 watts > nope, examining further: > .35,0,0 Power = 0.2285 watts > nope, looks like the one before at .30,0,0 is the new sweet spot. > > Now, to proceed to investigate the other quadrants to see if there is > symmetry: > -3.5,0,0 Power = 0.03997 watts > 0,3.5,0 Power = 0.005925 watts > 0,-3.5,0 Power = 0.005859 watts > > This last offers that on the Y axis there is a strong symmetry, and > along the X axis there is a moderate symmetry. Now, in regard to both > the X and the Y axis, there is a moderate symmetry. If we were to > look at the fine data attempting to find the peak, we should notice > that the "center" of the antenna lies between the "driven" element and > its reflector. My having chosen the "driven" element as the nominal > center was in error and my guess is that if I re-visited the same > quadrant test above, with that new center at the sweet spot, then we > would find very strong symmetry in all four quadrants. I will add > that the Y axis data supports this due to its strong symmetry that is > relatively immune from the choice of antenna center - at least at this > scale. > > Putting that aside, it is enough to suggest that barring an > exquisitely positioned peak of rather a sharp rise, then the yagi > exhibits a poorer response compared to a dipole of approx. 1.4dB. > > Others are encouraged to investigate further to reclaim that missing > dB or to put the horns to my error. > > 73's > Richard Clark, KB7QHC Hi Richard, I think what you're seeing is the 3-D interference pattern generated by your sources. I'm not sure that really tells us very much about the antennas themselves. You'd need to surround each of the antennas with a uniform field in order to compare them. By uniform, I mean the field intensity toward the antenna is the same in any direction. Thanks, AC6XG Article: 219124 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Message-ID: Date: Mon, 07 Nov 2005 19:52:04 GMT RB wrote: > Got a Radio Works choke balun I'd like to use for feeding ladderline out of > an unbalanced tuner. > > The balun has coax fittings on each end. Sounds like it is actually a UNUN. > I can kluge a PL-259 plug onto the ladderline. That will work. I usually just splice a short piece of coax to the ladder-line. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219125 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: AM Commercial radio reception References: <5587-436F9B87-955@storefull-3256.bay.webtv.net> Message-ID: Date: Mon, 07 Nov 2005 19:54:05 GMT Richard Harrison wrote: > I don`t know but from my own experience, the number is large. I would guess that the majority of US AM antennas that I have seen with my own eyes have more than one element. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219126 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Message-ID: Date: Mon, 07 Nov 2005 19:57:25 GMT Ed wrote: >>Got a Radio Works choke balun I'd like to use for feeding ladderline >>out of an unbalanced tuner. >> > I'm sure others here will correct me if I'm wrong, but I believe that > what you want to do is a very bad idea. Baluns are not meant to operate > under the potential very high SWR conditions ... It depends on whether the very high SWR is on the ladder-line side or on the coax side. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219127 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Antenna gain question References: Message-ID: Date: Mon, 07 Nov 2005 20:01:38 GMT Jim Kelley wrote: > I think what you're seeing is the 3-D interference pattern generated by > your sources. Richard is not trying to superpose powers again, is he? :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219128 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <1131391412.105801.165550@z14g2000cwz.googlegroups.com> Message-ID: Date: Mon, 07 Nov 2005 20:04:07 GMT JimK2TL@gmail.com wrote: > Why are you using a choke at that point in the system? You should use > either a 1:1 or 4:1 current balun ... A properly designed choke performs the function of a balun very well - witness the W2DU choke-balun. If the common-mode currents are choked off in the coax direction, they must necessarily flow in the ladder- line direction. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219129 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: how to combat noise? References: <1131365048.980502.250150@z14g2000cwz.googlegroups.com> <1131391877.551800.193000@z14g2000cwz.googlegroups.com> Message-ID: Date: Mon, 07 Nov 2005 20:08:07 GMT JimK2TL@gmail.com wrote: > How about trying to locate the source of the noise? The source of noise at my QTH is the 33 ft. ground wire running down the pole in my front yard from the giant old-as-Methuselah capacitor mounted there. It generates S7 noise on 40m. Maybe an RF choke would work? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219130 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer References: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> Message-ID: <4wObf.16054$dO2.12920@newssvr29.news.prodigy.net> Date: Mon, 07 Nov 2005 20:09:36 GMT Tam/WB2TT wrote: > Only thing I can add is that it eats batteries, ... I run mine off an external rechargable 12v YUASA battery. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219131 of rec.radio.amateur.antenna From: "RB" References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Subject: Re: ladderline to coax adapter Message-ID: <_dPbf.8637$Dk.2880@bignews5.bellsouth.net> Date: Mon, 7 Nov 2005 15:00:10 -0600 Thanks, Cecil. Guess that's what I'll do. I don't think there is any "graceful" way of going from ladderline to coax. }}} Sounds like it is actually a UNUN. {{{ I THOUGHT the choke baluns are unbalanced to balanced, and will work OK for the purpose of feeding ladderline. Although they're electrically symmetrical (unbalanced rf goes in one end, and balanced rf comes out the other. Flip 'em around and it's the same, either way). If they're not, I need to know it so I can go to another kind. Article: 219132 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <_dPbf.8637$Dk.2880@bignews5.bellsouth.net> Message-ID: Date: Mon, 07 Nov 2005 21:29:17 GMT RB wrote: > }}} Sounds like it is actually a UNUN. {{{ > > I THOUGHT the choke baluns are unbalanced to balanced, and will work OK for > the purpose of feeding ladderline. I was half joking. A choke can often function equally well as a UNUN or a BALUN. A W2DU choke, for instance, doesn't "know" whether it is in a balanced or unbalanced environment. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219133 of rec.radio.amateur.antenna From: "Michael" Subject: Loop Antennas Date: Tue, 8 Nov 2005 13:51:06 -0800 Message-ID: <11mvjfic11rdq9f@corp.supernews.com> I get a lot of noise from my random wire antenna. It transmits very well but is very noisy in receive. My neighbor put up a 280 foot loop antenna which he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his house at a 30 ft. height. It is arranged in a square. Has anybody else had this experience with loops? It looks like I have room to put up a triangular loop. Will this work as well? Can I use the same tuner I have now and just feed a coax into a balun. Or, should I put the balun in the tuner and come straight out with ladder line? There is a lot of room in this tuner. It is an old remote controlled tuner surplused from a ship. Article: 219134 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Loop Antennas Message-ID: <46lvm150mg8kt9s377qhrfb18ct12esheo@4ax.com> References: <11mvjfic11rdq9f@corp.supernews.com> Date: Mon, 07 Nov 2005 22:32:46 GMT On Tue, 8 Nov 2005 13:51:06 -0800, "Michael" wrote: >I get a lot of noise from my random wire antenna. It transmits very well but >is very noisy in receive. My neighbor put up a 280 foot loop antenna which Ok. >he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to >coax. The coax comes from a tuner. His setup performs very well on all bands >down to 75 meters. I went over to his shack last night and listened to his >receiver on 75. I was really impressed with the lack of noise. I can safely >say the difference in noise was profound. He has this loop surrounding his So, the noise is "profoundly" less (whatever that means), but what about signals that you want to hear, and how does it perform transmitting. You see, a 30dB attenuator would profoundly reduce the noise.... and the desired receive signals, and the tx signal, but it isn't necessarily better. You probably know the answers, you just didn't tell us. It is often the case that the best antenna for transmission is the one that makes the most noise where you want to be heard, and the best antenna for receiving is the one that gives the best S/N ratio (not necessarily the best S meter deflection) for stations from that place, and they may not be the same antenna. Owen -- Article: 219135 of rec.radio.amateur.antenna Subject: Re: ladderline to coax adapter From: Ed References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Message-ID: Date: Mon, 07 Nov 2005 22:35:45 GMT Cecil Moore wrote in news:FkObf.16049$dO2.15833@newssvr29.news.prodigy.net: > Ed wrote: > >>>Got a Radio Works choke balun I'd like to use for feeding ladderline >>>out of an unbalanced tuner. >>> >> I'm sure others here will correct me if I'm wrong, but I believe >> that >> what you want to do is a very bad idea. Baluns are not meant to >> operate under the potential very high SWR conditions ... > > It depends on whether the very high SWR is on the ladder-line > side or on the coax side. :-) Well, he said "OUT of an unbalanced tuner" so I assume that's the ladderline side. Ed K7AAT Article: 219136 of rec.radio.amateur.antenna Subject: Re: ladderline to coax adapter From: Ed References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <_dPbf.8637$Dk.2880@bignews5.bellsouth.net> Message-ID: Date: Mon, 07 Nov 2005 22:39:33 GMT Cecil Moore wrote in news:NGPbf.16074$dO2.15408@newssvr29.news.prodigy.net: > RB wrote: >> }}} Sounds like it is actually a UNUN. {{{ >> >> I THOUGHT the choke baluns are unbalanced to balanced, and will work >> OK for the purpose of feeding ladderline. > > I was half joking. A choke can often function equally well > as a UNUN or a BALUN. A W2DU choke, for instance, doesn't > "know" whether it is in a balanced or unbalanced environment. Guys, please help me here. You are talking about UNUNs and BALUNs. A balanced tuner OUTPUT to ladderline is BALANCED TO BALANCED , isn't it? Why the need for anything, there? Ed K7AAT Article: 219137 of rec.radio.amateur.antenna From: "Richard Fry" References: <6487-436C4D06-493@storefull-3252.bay.webtv.net> Subject: Re: AM Commercial radio reception Date: Mon, 7 Nov 2005 16:50:09 -0600 Message-ID: <436fd96a_3@newsfeed.slurp.net> "Dave Pitzer" wrote > ... Is there any place I can find polar graphs of commercial > broadcast station's antenna patterns? ___________________ Dave, Here http://www.radio-locator.com/ is a link to a website with calculated coverage areas/contours for US AM broadcast stations. The contours are based on their licensed radiation patterns (directional or not), AND ground conductivities for the geographic regions concerned. The polar radiation patterns of these stations most probably don't look much like these plots, because of the heavy influence that ground conductivity has on received field strength along the various azimuth bearings. Even the real coverage contours of AM broadcast stations using omni antennas usually are anything but omni, due to the effects of varying ground conductivities around their various azimuth sectors and ranges. Have fun. RF Article: 219138 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Antenna gain question Date: Mon, 07 Nov 2005 15:08:26 -0800 Message-ID: <11mvnjbidllgk21@corp.supernews.com> References: Jim Kelley wrote: > > Hi Richard, > > I think what you're seeing is the 3-D interference pattern generated by > your sources. I'm not sure that really tells us very much about the > antennas themselves. You'd need to surround each of the antennas with a > uniform field in order to compare them. By uniform, I mean the field > intensity toward the antenna is the same in any direction. How about polarization? Roy Lewallen, W7EL Article: 219139 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: <6dnvm1p0vl55qceve3dca1ueqpq7tbn0cp@4ax.com> References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Date: Mon, 07 Nov 2005 23:17:18 GMT On Mon, 7 Nov 2005 12:07:30 -0600, "RB" wrote: >Got a Radio Works choke balun I'd like to use for feeding ladderline out of >an unbalanced tuner. > >The balun has coax fittings on each end. I think from the sound of your description you have one of their "isolaters" that has a coax socket on both ends. These things are very neat when used to "choke" currents on the outer of coax. > >Ladderline doesn't adapt well to coax interfaces. > >What's the best way to put ladderline to my balun coax fitting? > >I can kluge a PL-259 plug onto the ladderline. > >I guess I could also stick one side of the ladderline in the center hole of >the chassis coac fitting, and clamp the other side to the threaded part of >the chassis fitting. That doesn't sound reliable, the "stick one side of the ladderline in the center hole" bit, that is. How would you maintain reliable centre contact. (BTW, you probably already know that 4mm banana plugs fit into SO-239 neatly.) What is your problem, is it the "inelegance" of soldering the openwire ends to the coax plug, or are you concerned about impedance discontinuity at presumably HF / 6m? I am sure that you could look around and find adapters, I can think of a few ways myself, but... If it is not in the weather, I would just solder the ends of the open wire to a PL-257 and screw in on. You could sleeve the end going to the centre conductor to improve its flashover voltage if that is likely to be an issue. (BTW, taking the earth side wire down inside the PL259 and bringing it out the braid hole will give you quite a neat finish.) Owen -- Article: 219140 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Passive battery switch RFID Date: Mon, 07 Nov 2005 17:23:36 -0600 Message-ID: <11mvofvo8s0j0ae@corp.supernews.com> References: <11mb4663b5c2dd2@corp.supernews.com> Passive rfid transponders can be made with greater range than you have experienced. For instance the Illinois Toll Roads have implemented what they call IPASS. This is a RFID that operates at highway distances and speeds. With IPASS you place the rfid in the center of your car/truck window and when you go through a toll plaza the reader induces an electrical current in the transponder. This current activates the coded transmitter which is read by the plaza receiving equipment. Each and every transponder that passes the reader is interrogated. The induction field is constant and activates the transponder as it is passed. There is another device called SPEED PASS that is used by Mobile Oil CO. The transponder is contained in a small plastic capsule shaped package. I took one apart and examined the contents. The transponder is contained inside a glass capsule and consists of a small (1/8") diameter coil that is connected to a small pc board with an IC and some other components. The entire thing is about 1/2" long. Range for this device is very short since it is associated with you credit card. I don't know how big an inductor is needed to provide enough power to transmit over the ranges you are looking at but some simple experimentation should answer this. Basically what the inductor is half of a transformer. The field generator is the other half. The power generated can be used to activate a transistor switch to provide power to the transmitter. For more information it would be best to do a google search on RFID and see what else is available. Good luck Dave Nagel fh03 wrote: > David, can you please elaborate on how this can be done? And how it can > be implemented so that the proper signal activates the unit. > > I'm sort of a newbie in this field and would appreciate it if you could > explain how this can be done in greater detail. > > Thanks again. > > David G. Nagel Wrote: > >>Use the passive receiver to power a transistor switch to activate the >>transmitter. You should be able to induce enough power in the unit to >>switch some kind of transistor switch connecting the battery to the >>second stage of the unit. You would have to be careful that only the >>proper signal activates the unit though. >> >> >>Dave WD9BDZ >> >> >> >>fh03 wrote: >> >>thanks for your input guys. I havent been able to come online due to >>power outages caused by hurricane wilma. >> >>anyway. the reed switch mentioned would work, but the distance is the >>issue. I currently have an rfid reader and passive tag, but they too >>work only within a few inches. What I need is for the device to be >>activated within 5 feet of the receiver and from my understanding a >>reed switch cant do that. >> >>I know electronic toll payment systems seem to conserve battery, and >>thats what i need. Bascially I want to have a battery in the unit, >>but >>I dont want the battery to be connected until we're in that range. >>The >>reason passive devices dont work is because even though the antenna >>can >>provide an induced current, without a battery the tag doesnt have >>enough >>power to be able to transmit over say a few inches, let alone five >>feet. >>So we need battery in the transmitter. The user only carries a >>transmitter, so it doenst know when it is within range. I have a >>microcontroller that will transmit an ID as soon as it is powered up, >>but I dont want it to be on at all times, and I dont want a switch. >>I'll look into the "Hall Effect" now and see what its about. >> >>Thanks again guys, keep it coming. >> >> > > > Article: 219141 of rec.radio.amateur.antenna From: "Steve Nosko" Subject: Re: How To Put Up An Antenna Date: Mon, 7 Nov 2005 16:42:18 -0600 Message-ID: References: <43683106.A6993A2E@shaw.ca> <11mim54bve97rcc@corp.supernews.com> <11mio1h6a2td18f@corp.supernews.com> "Hal Rosser" wrote in message news:M_Uaf.43044$ty1.22897@bignews1.bellsouth.net... > Oh - of COURSE its a false story - just a good funny one. > We all know hams don't use buckets for their tools. > It was on some ftp site in the early 90's I think... everyone knew it was > just a joke - but you couldn't help but snicker as each paragraph > introduced a new wrinkle and a new woe to the unlucky ham. > It was written up like it was an explanation to his insurance company. > > "David G. Nagel" wrote in message > news:11mio1h6a2td18f@corp.supernews.com... > > Roy Lewallen wrote: > > > Hal Rosser wrote: > > > > > >> That reminds me of a story that used to circulate .... > > Mythbusters looked into this myth and ircc they found it not only false > > but impossible. I could be wrong though. > > > > Dave WD9BDZ > > The best part of the (obvious) joke was that it WAS possible as stated, if not probable. That is to say, the physics of the story I saw was indeed correct (assuming he brought up that many tools- which is probably the fatal flaw in the screen play). I think the one I saw had him use an old wooden barrel (easier to break apart upon contact w/ the ground) 73, Steve, K.9/D'C;I Article: 219142 of rec.radio.amateur.antenna From: "Steve Nosko" Subject: Re: Lunch Tomorrow Date: Mon, 7 Nov 2005 16:45:04 -0600 Message-ID: References: Ahhh! Brain full. How well I know. 73, Steve, K9DCI "Henry" wrote in message news:dkk32401dbi@enews4.newsguy.com... > Dave wrote: > > "Henry" wrote in message > > news:dkjjsu031g4@enews3.newsguy.com... > > > >>Be here before 12:00 for lunch. > >> > >>CU then. > >> > >>Love > >> > >>Dad > > > > > > what you having?? > > > > > ROTFL I was in this newsgroup when I thought I was in my email > program and I sent the message to my son. I called him later and he > said he didn't get the email. I'll try to be more carefull, but it > sure is funny to me. :-) > > Henry Article: 219143 of rec.radio.amateur.antenna From: "Steve Nosko" Subject: Re: how to check balun Date: Mon, 7 Nov 2005 16:51:28 -0600 Message-ID: References: <11mt89rl4nm5a17@corp.supernews.com> <_lybf.2649$kd.2028@bignews4.bellsouth.net> Roy forgot to mention / stress that a balun is designed for specific impedances. If it is a common 1:1 balun, then it is probably designed for 50 ohms. They are designed for feeding a 1/2 wave dipole or similar antenna, not widely different (from 50) impedances. Steve, K,9.D;C'I "RB" wrote in message news:_lybf.2649$kd.2028@bignews4.bellsouth.net... > Wow! Good info, Roy. Thanks. That should get me going, at least. > > Article: 219144 of rec.radio.amateur.antenna From: "Steve Nosko" Subject: Re: My antennas are on QRZ's cover Date: Mon, 7 Nov 2005 16:46:20 -0600 Message-ID: References: <436d752d$0$32205$39cecf19@news.twtelecom.net> <436d7c07$0$3756$39cecf19@news.twtelecom.net> Rats RO K 73, Steve, K,9.D;C'I "Tom Ring" wrote in message news:436d7c07$0$3756$39cecf19@news.twtelecom.net... > Tom Ring wrote: > > > The 4 over 4 above it is rotarable. > > And I don't type well. > Article: 219145 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Message-ID: Date: Mon, 07 Nov 2005 23:26:47 GMT Ed wrote: > Cecil Moore wrote: >>It depends on whether the very high SWR is on the ladder-line >>side or on the coax side. :-) > > Well, he said "OUT of an unbalanced tuner" so I assume that's the > ladderline side. Yes, and with a reasonable limit, the SWR on the ladder-line doesn't matter. IMO, 25:1 is no problem for ladder-line. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219146 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Loop Antennas References: <11mvjfic11rdq9f@corp.supernews.com> Message-ID: <%sRbf.9599$BZ5.7386@newssvr13.news.prodigy.com> Date: Mon, 07 Nov 2005 23:31:07 GMT Michael wrote: > Has anybody else had this experience with loops? Only the past three generations. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219147 of rec.radio.amateur.antenna From: "Hal Rosser" References: <11mvjfic11rdq9f@corp.supernews.com> Subject: Re: Loop Antennas Message-ID: Date: Mon, 7 Nov 2005 18:43:36 -0500 Ah yes grasshopper - zee loops - zay are good. The loop helps reduce noise since its dc-shorted and no static buildup, and your socks won't stick to it. ;-) but it takes more trees to hold it up "Michael" wrote in message news:11mvjfic11rdq9f@corp.supernews.com... > I get a lot of noise from my random wire antenna. It transmits very well but > is very noisy in receive. My neighbor put up a 280 foot loop antenna which > he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to > coax. The coax comes from a tuner. His setup performs very well on all bands > down to 75 meters. I went over to his shack last night and listened to his > receiver on 75. I was really impressed with the lack of noise. I can safely > say the difference in noise was profound. He has this loop surrounding his > house at a 30 ft. height. It is arranged in a square. > > Has anybody else had this experience with loops? It looks like I have room > to put up a triangular loop. Will this work as well? > > Can I use the same tuner I have now and just feed a coax into a balun. Or, > should I put the balun in the tuner and come straight out with ladder line? > There is a lot of room in this tuner. It is an old remote controlled tuner > surplused from a ship. > > Article: 219148 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Date: Mon, 07 Nov 2005 15:46:25 -0800 Message-ID: <11mvpqjme2l7ge0@corp.supernews.com> References: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> Tam/WB2TT wrote: > > I am happy with mine. Only thing I can add is that it eats batteries, and my > unit does not like to work below 13 Volts. They do sell a tunable bandpass > filter for the lower frequencies. I tried a high pass filter - don't bother, > it messes up the phase. If you do want to measure antenna impedance with something like the MFJ and have trouble (as I do) with local broadcasting and other RF, I recommend using a "half wave" filter. This type of filter has reasonable out-of-band attenuation characteristics and doesn't disturb the impedance measurement too much. (Over a limited frequency range it mimics a half wavelength of transmission line.) The impedance disturbance will be the least when the filter is designed to approximately match the measured impedance. It's simply two cascaded pi sections, with each element having the same value of X. For example, a lowpass looks like this: ---.---L---.---L---.--- | | | C 2C C | | | ----.-------.-------.--- For example, a filter with Z0 = 50 ohms (one which mimics a half wavelength of 50 ohm line) has XL = XC = 50. One designed for 7 MHz would have L = 1.14 uH, C = 455 pF. You can wind the coils on small type 2 or 6 powdered iron cores, and use the closest standard value (e.g., 470 pF) for the capacitors. This filter will cause little impedance disturbance at 7 MHz and, for load impedances near 50 ohms, at lower frequencies also. A highpass looks like this: ---.---C---.---C---.--- | | | L L/2 L | | | ----.-------.-------.--- Again, XL = XC = the filter Z0. Make filters according to your particular measurement needs. You can check the amount of disturbance the filter causes by making a known impedance out of a resistor and capacitor or inductor which is about equal to the measured impedance, and measuring it with and without the filter. If you can read German, there's a marvelous book describing how to make a wide variety of measurements with an antenna analyzer, with tricks, tips, and details. It's _HF-Messungen mit einem aktiven Stehwellen-Meßgerät_ by Gerd Janzen, DF6SJ. It's available directly from him at Hochvogelstraße 29, D-87435 Kempten, Germany. Roy Lewallen, W7EL Article: 219149 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: Antenna gain question Date: Mon, 07 Nov 2005 15:40:58 -0800 Message-ID: References: <11mvnjbidllgk21@corp.supernews.com> Roy Lewallen wrote: > Jim Kelley wrote: > >> >> Hi Richard, >> >> I think what you're seeing is the 3-D interference pattern generated >> by your sources. I'm not sure that really tells us very much about >> the antennas themselves. You'd need to surround each of the antennas >> with a uniform field in order to compare them. By uniform, I mean the >> field intensity toward the antenna is the same in any direction. > > > How about polarization? > > Roy Lewallen, W7EL Hi Roy, Your guess is better than mine. I think in order not to bias the results, the solution would have to be that each source is randomly polarized, i.e. the Sun redshifted down into the radio spectrum - coming >from every direction. The ring of point sources is an interesting approach. One could use rings at some number of elevation angles, both above and below the plane of the antennas. The greater the elevation angle, the smaller the diameter of the ring such that the radial distance to the antenna is kept constant. But I imgaine you have ideas of your own in this regard. 73, ac6xg Article: 219150 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Date: Tue, 08 Nov 2005 00:07:14 GMT On Mon, 07 Nov 2005 23:26:47 GMT, Cecil Moore wrote: >Yes, and with a reasonable limit, the SWR on the ladder-line >doesn't matter. IMO, 25:1 is no problem for ladder-line. There must be a host of unstated assumptions behind that statement to make it valid in a limited scenario. Using TLDETAILS to work up a load of 16+j0 on 100m of Wireman551 ladder-line at 30MHz, the predicted VSWR varies between 25 at the load end and a very modest 6.5 at the generator end, yet the predicted loss is around 6dB. Some might not find that an acceptable loss. Owen -- Article: 219151 of rec.radio.amateur.antenna From: "Falky foo" References: <436d752d$0$32205$39cecf19@news.twtelecom.net> Subject: Re: My antennas are on QRZ's cover Message-ID: Date: Tue, 08 Nov 2005 00:22:57 GMT nice photo actually "Tom Ring" wrote in message news:436d752d$0$32205$39cecf19@news.twtelecom.net... > I wouldn't have voted for them, but my friend, Geoff KC0FXY, did take a > nice shot. And I guess QRZ thought so too. > > https://secure.qrz.com/store/qrz_cd.html > > So my 6 meter beams are on the 2005-2006 cover. > > To explain the shot, the lower beam is a fixed 3 element which is meant > to cover the Minneapolis/St Paul metro area. > > The 4 over 4 above it is rotarable. > > tom > K0TAR Article: 219152 of rec.radio.amateur.antenna From: "Michael" Subject: Re: Loop Antennas Date: Tue, 8 Nov 2005 17:08:20 -0800 Message-ID: <11mvunacdnek8cf@corp.supernews.com> References: <11mvjfic11rdq9f@corp.supernews.com> <46lvm150mg8kt9s377qhrfb18ct12esheo@4ax.com> ">>I get a lot of noise from my random wire antenna. It transmits very well but >>is very noisy in receive. My neighbor put up a 280 foot loop antenna which > > Ok. > >>he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to >>coax. The coax comes from a tuner. His setup performs very well on all >>bands >>down to 75 meters. I went over to his shack last night and listened to his >>receiver on 75. I was really impressed with the lack of noise. I can >>safely >>say the difference in noise was profound. He has this loop surrounding his > > So, the noise is "profoundly" less (whatever that means), but what > about signals that you want to hear, and how does it perform > transmitting. Well, I would not be raving about his antenna if it also reduced the signals you want to hear. He gets the same kind of signal reports that I do. We were both on the same net one night and we were both be received equally at various spots. Clearly, mine transmits as well as his. > > You see, a 30dB attenuator would profoundly reduce the noise.... and > the desired receive signals, and the tx signal, but it isn't > necessarily better. When I listened to our local North Dakota Data Net, I heard all the checkins like they were much much closer. No Noise! I should have been more specific. The S?n ratio was profoundly better than my puny random wire. However, I do not know yet if I am up to putting up 3 or 4 32 foot poles or higher. What a drag. I will probably do this next spring. It is getting too cold to make the task a very pleasant one now. > > You probably know the answers, you just didn't tell us. > > It is often the case that the best antenna for transmission is the one > that makes the most noise where you want to be heard, and the best > antenna for receiving is the one that gives the best S/N ratio (not > necessarily the best S meter deflection) for stations from that place, > and they may not be the same antenna. > > Owen > -- Article: 219153 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Antenna gain question Date: Mon, 7 Nov 2005 20:16:13 -0500 Message-ID: <11mvv2542t28l88@corp.supernews.com> References: <10021-43698257-110@storefull-3251.bay.webtv.net> See comment below. -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Richard Harrison" wrote in message news:10021-43698257-110@storefull-3251.bay.webtv.net... > Jim Kelley, AC6XG wrote: To a first approximation > though, we assume that all the parallel rays intercepted by a dish are > focused on the radiator and aid, adding in-phase. Received carrier power > excites the antenna and this causes a minimum of 50% of this power to be > re-radiated if the antenna is perfectly matched to to the receiver load. > The antenna`s radiation resistance in this case becomes the Thevenin`s > source resistance for the receiver load on the antenna. This requires a > conjugate match between the antenna and receiver input impedances. ----- ... not if one wishes to maximize SNR. Best SNR requires a (slight) mismatch. Of course, this issue is only significant if SNR is due to the noise figure (NF) of the receiver and the SNR is small. 73 Mac N8TT Article: 219154 of rec.radio.amateur.antenna From: "Crazy George" References: <6487-436C4D06-493@storefull-3252.bay.webtv.net> <436d6a27_3@news1.prserv.net> Subject: Re: AM Commercial radio reception Date: Mon, 7 Nov 2005 19:29:46 -0600 Message-ID: <43700313_1@news1.prserv.net> Reg: I don't have an accurate number for the entire country, but here in the local area, there is one clear channel station with a single radiator, a half dozen two tower arrays, two 3 tower arrays, five 4 tower arrays that I can recall off the top of my head. If you had asked a dozen years ago, I could have been more accurate. I don't think we have any 5 or 6 radiator arrays here locally, if so, I don't remember them. If my math is correct, that is a 50-50 split, so maybe half have more than 2 towers. -- Crazy George W5VPQ My real address is my ham call ARRL.NET The ATTGlobal is a SPAM trap. "Reg Edwards" wrote in message news:dkmvf3$onq$1@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com... > > "Crazy George" wrote >> I'm afraid you're way behind the practice on this one. In the US, > there are >> many 4, 5 and 6 tower arrays providing as many nulls to protect > co-channel > stations. > > ================================= > > What proportion of US MF broadcasting stations have antennas > consisting of more than two towers ? > ---- > Reg. > > Article: 219155 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Message-ID: Date: Tue, 08 Nov 2005 02:09:13 GMT Owen Duffy wrote: > Using TLDETAILS to work up a load of 16+j0 on 100m of Wireman551 > ladder-line at 30MHz, the predicted VSWR varies between 25 at the load > end and a very modest 6.5 at the generator end, yet the predicted loss > is around 6dB. Some might not find that an acceptable loss. If 100m (325 feet) of ladder-line results in 6dB loss, then a more realistic 75 feet of ladder-line will result in about 1.4 dB of loss. That's only 1/4 of an S-unit on the highest frequency HF band and less on the other bands. That's perfectly acceptable to me and virtually indistinguishable on an S-meter. If you have to resort to 325 feet of ladder-line on 30 MHz to try to prove me wrong, I feel really sorry for you. Why didn't you choose a million feet to prove me even more wrong? It appears that you are lurking there in the down under outback just waiting for me to forget to cross an 'i' or dot a 't'. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219156 of rec.radio.amateur.antenna Subject: Re: ladderline to coax adapter From: Ed References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> Message-ID: Date: Tue, 08 Nov 2005 02:19:47 GMT >> >> Well, he said "OUT of an unbalanced tuner" so I assume that's the >> ladderline side. > Yes, and with a reasonable limit, the SWR on the ladder-line > doesn't matter. IMO, 25:1 is no problem for ladder-line. Correct, a high SWR is not an issue for ladderline, but the guy was wanting to stick an apparently 50 ohm coax balun right there in between his balanced tuner output and that ladder line. I would think a high SWR, with some TX power, in that device might not do it much good. Ed Article: 219157 of rec.radio.amateur.antenna Subject: Re: ladderline to coax adapter From: Ed References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <_dPbf.8637$Dk.2880@bignews5.bellsouth.net> Message-ID: Date: Tue, 08 Nov 2005 02:27:22 GMT >> Guys, please help me here. You are talking about UNUNs and BALUNs. >> >>A balanced tuner OUTPUT to ladderline is BALANCED TO BALANCED , >>isn't it? Why the need for anything, there? > His original posting said: > "Got a Radio Works choke balun I'd like to use for feeding ladderline > out of an *unbalanced* tuner." My sincere appologies to this thread group. I read that original post twice and still missed that the tuner was unbalanced output. Makes a lot more sense, now. Ed K7AAT Article: 219158 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Date: Tue, 08 Nov 2005 03:07:10 GMT On Tue, 08 Nov 2005 02:09:13 GMT, Cecil Moore wrote: >Owen Duffy wrote: >> Using TLDETAILS to work up a load of 16+j0 on 100m of Wireman551 >> ladder-line at 30MHz, the predicted VSWR varies between 25 at the load >> end and a very modest 6.5 at the generator end, yet the predicted loss >> is around 6dB. Some might not find that an acceptable loss. > >If 100m (325 feet) of ladder-line results in 6dB loss, then a more >realistic 75 feet of ladder-line will result in about 1.4 dB of loss. Close, I make it 2.2dB. (The loss per meter is not a constant figure in this situation.) Agreed, even that is not a large amount, and indeed might be quite acceptable in many / most cases. >That's only 1/4 of an S-unit on the highest frequency HF band and less >on the other bands. That's perfectly acceptable to me and virtually >indistinguishable on an S-meter. > >If you have to resort to 325 feet of ladder-line on 30 MHz to try >to prove me wrong, I feel really sorry for you. Why didn't you choose >a million feet to prove me even more wrong? It appears that you are >lurking there in the down under outback just waiting for me to forget >to cross an 'i' or dot a 't'. Cecil, people often employ long runs of open wire feed on HF (ie up to 30MHz), and it just shows that on longer runs, high VSWR can be an issue for ladder line. I often hear Rules of Thumb (ROT) like VSWR < 3 is OK for coax and < 25 if fine for open wire, or the converse... but something is lost in the brief expression of those ROTs, and it seems more and more the knowledge base of our hobby is the ROTs, rather than the underlying principles. There is an appeal to the new experts in our hobby to pickup the ROTs and parrot them... perhaps we need to take the time to qualify what we say where learners are listening. Owen -- Article: 219159 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Subject: Re: ladderline to coax adapter Date: Mon, 7 Nov 2005 22:21:35 -0500 Message-ID: <998ee$43701a24$97d56a33$13066@ALLTEL.NET> How many hams find a feedline length of 100 Meters acceptable? Lets look at a more realistic length of 100 feet and the loss is less than 2 dB at 30 Mhz. The loss is much less on the lower bands. With all due respect, your example sucks! "Owen Duffy" wrote in message news:9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com... > On Mon, 07 Nov 2005 23:26:47 GMT, Cecil Moore wrote: > > > >Yes, and with a reasonable limit, the SWR on the ladder-line > >doesn't matter. IMO, 25:1 is no problem for ladder-line. > > There must be a host of unstated assumptions behind that statement to > make it valid in a limited scenario. > > Using TLDETAILS to work up a load of 16+j0 on 100m of Wireman551 > ladder-line at 30MHz, the predicted VSWR varies between 25 at the load > end and a very modest 6.5 at the generator end, yet the predicted loss > is around 6dB. Some might not find that an acceptable loss. > > Owen > -- Article: 219160 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Date: Tue, 08 Nov 2005 03:40:33 GMT On Mon, 07 Nov 2005 19:16:08 -0800, Dan Richardson <> wrote: >On Tue, 08 Nov 2005 03:07:10 GMT, Owen Duffy wrote: > >>I often hear Rules of Thumb (ROT) like VSWR < 3 is OK for coax and < >>25 if fine for open wire, or the converse... but something is lost in >>the brief expression of those ROTs, and it seems more and more the >>knowledge base of our hobby is the ROTs, rather than the underlying >>principles. There is an appeal to the new experts in our hobby to >>pickup the ROTs and parrot them... perhaps we need to take the time to >>qualify what we say where learners are listening. >> >>Owen > >Owen, > >The problem is that knowing the SWR is not worth much without knowing >the frequency and the spec's of the transmission line. ... including the length. I agree fully. Owen -- Article: 219161 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> Date: Tue, 08 Nov 2005 03:48:23 GMT On Mon, 7 Nov 2005 22:21:35 -0500, "Fred W4JLE" wrote: >How many hams find a feedline length of 100 Meters acceptable? Lets look at >a more realistic length of 100 feet and the loss is less than 2 dB at 30 >Mhz. The loss is much less on the lower bands. With all due respect, your >example sucks! BTW, I make your example 2.7dB, not less than 2dB. (Perhaps you labour under the misaprehension that loss per unit length is a constant in this situation). Fred, what you have highlighted is the unstated assumption of some limit on length. You know enough to choose a length so that the ROT is true, but does a learner soaking this up know as much? Owen -- Article: 219162 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: ladderline to coax adapter Date: Tue, 8 Nov 2005 04:09:15 +0000 (UTC) Message-ID: References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Dan Richardson wrote - > The problem is that knowing the SWR is not worth much without knowing > the frequency and the spec's of the transmission line. > ================================== The REAL problem is that very few people know the SWR on the transmission line because the SWR meter doesn't measure it. Aren't you are fooling yourselves? ---- Reg. Article: 219163 of rec.radio.amateur.antenna From: "Charlie" Subject: Add WARC Bands - 12M and 17M to Hustler 4-BTV, 5-BTV, or 6-BTV Date: Mon, 7 Nov 2005 22:22:27 -0600 Message-ID: <11n0a0lhlf0vh02@news.supernews.com> Takes about 1 hour assembly time and costs less then $15. Takes legal limit and requires no permanent modifications to original Hustler BTV antennas. SWR on 12M and 17M < 1.2:1 This mod adds a 12M and a 17M vertical radiator on each side of the existing Hustler antenna. Minor retuning of original bands required after 12M and 17M are tuned. It's EASY! This works a treat and is a great way to get an extra 2 bands from an existing antenna structure. 1. http://www.ad5th.com/5-BTV-WARC.html -- Charlie-AD5TH Article: 219164 of rec.radio.amateur.antenna From: mcalhoun@ksu.edu Subject: Re: 135' flattop Date: 7 Nov 2005 22:39:27 -0600 Message-ID: References: <4srsm1hkm37tbakooehau801uph9fmctsf@4ax.com> <16pum1d23nfpo0fk38ptisqhkek4gdhte1@4ax.com> >I copied this out of the MFJ-269 antenna analyzer manual: >"Resonance at the feedpoint only repeats when a mismatched feedline is >....[snip].... Unless I missed it, thta quote from the MFJ manual didn't actually say "The subject is a single-frequency (or even single-band) antenna". For a multi-frequency/band antenna, isn't ANY feedline ALWAYS going to be mis-matched on at least SOME of those frequencies/bands? -- --Myron A. Calhoun. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) Article: 219165 of rec.radio.amateur.antenna From: mcalhoun@ksu.edu Subject: Re: What Would You Do?? Date: 7 Nov 2005 23:27:30 -0600 Message-ID: References: <89xbf.14860$td.1301@bignews3.bellsouth.net> >>Years ago I cleared a 200 foot path in among some hard woods.... >>In this path I've got two 120 foot towers in line with Europe. The >>towers are 500 feet apart......Its pretty well open on the sides >>....[snip].... If those two towers are truly IN LINE with Europe, won't 'most any antenna you hang BETWEEN them (i.e., from one tower to another, like a Sterba or several half-squares) radiate 90 degrees AWAY from Europe? To make an antenna that radiates TOWARD Europe, you could make a "wire beam" by using a rope or wire strung between the towers as a "boom", create "elements" by throwing several essentially-half-wavelength-long inverted-V's ACROSS that "boom" spaced some fraction of a wavelength apart, use the "element" farthest from Europe as a "reflector", feed the next one, and use the others as directors. Ergo sum, a humongous beam "in line" with Europe! -- --Myron A. Calhoun. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) Article: 219166 of rec.radio.amateur.antenna From: 'Doc Subject: Re: Loop Antennas References: <11mvjfic11rdq9f@corp.supernews.com> Message-ID: Date: Tue, 08 Nov 2005 06:11:59 GMT Michael, I've had sort of the same experience with a loop antenna. I'd say it was probably about the same for most everyone. As far as where to put the balun and how to feed the thing, I honestly don't think it's going to make much difference. What would be easiest and 'best' for you? That's how I'd do it... 'Doc PS - Are loops the 'end-all of antennas? Huh, good question, and the answer is probably, no. But, I've had good luck with mine... Article: 219167 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Date: Tue, 08 Nov 2005 03:36:46 -0800 Message-ID: <11n13ejlg4b2o7b@corp.supernews.com> References: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> <11mvpqjme2l7ge0@corp.supernews.com> <0smdnetLAMKSpu3eRVn-pw@comcast.com> Tam/WB2TT wrote: > > I will have to try your configuration. I did C - L - C/2 - L -C, with > C=1000PF, L=2.2uH. According to SWCad, the gain is flat above 2 MHz, but > there is 120 degrees phase shift at 4 MHz, relative to the phase at 100 MHz. The center component should be 2C, or 2000 pF for your experiment, not C/2. The circuit is simply two pi networks in cascade, each having all component reactances equal to the "transmission line" Z0. Each pi section mimics a quarter wave transmission line. Roy Lewallen, W7EL Article: 219168 of rec.radio.amateur.antenna From: "Mike" Subject: Naval connection? You qualify for RNARS membership! Date: Tue, 8 Nov 2005 11:58:49 +0000 (UTC) Message-ID: Membership of the Royal Naval Amateur Radio Society (RNARS) is open to all who have an interest in any facet of amateur radio and who are serving or who have served in the following: Royal Navy Royal Marines Royal Naval Reserve Royal Marine Reserve Women's Royal Naval Service Royal Naval Auxiliary Service Royal Fleet Auxiliary Merchant Navy Sea Cadets Corps Nautical Training Corps MOD (Navy) Commonwealth and Foreign Navies NON-MEMBERS can purchase RNARS commodities. Details and membership application form is available online at http://www.rnars.org.uk Article: 219169 of rec.radio.amateur.antenna From: Mike Luther Subject: Re: new babe to RFID design want to ask some question Date: Tue, 08 Nov 2005 14:27:27 +0000 Message-ID: <11n1de9tdtvm6c1@corp.supernews.com> References: <1131433887.459126.289100@o13g2000cwo.googlegroups.com> Just wondering .. Dave wrote: >why >don't you just go buy the hardware from someone who has already done all the >design and testing and just use their system? or get a hardware engineer to >do what they do best and figure out what your system requirements need? >there are probably dozens of off the shelf rfid manufacturers out there, >just pick the range and type of data you need and you should be able to find >one that will give you just what you want. > > What RF hash level at the used frequency or frequencies can trash the operational effectiveness of the currently 'of interest' RFID devices and systems? A watt or two from how many feet away? How many more watts from how much further away could ruin a perceived 'secure' technology? Inquiring mind wants to know. W5WQN -- --> Sleep well; OS2's still awake! ;) Mike Luther Article: 219170 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Message-ID: <4d3cf.11958$q%.10105@newssvr12.news.prodigy.com> Date: Tue, 08 Nov 2005 15:09:52 GMT Owen Duffy wrote: >>It appears that you are >>lurking there in the down under outback just waiting for me to forget >>to cross an 'i' or dot a 't'. > > Cecil, people often employ long runs of open wire feed on HF (ie up to > 30MHz), and it just shows that on longer runs, high VSWR can be an > issue for ladder line. Guess I should have put a smiley face on my above posting. Did you miss the humor? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219171 of rec.radio.amateur.antenna From: "W5GT" References: Subject: Re: 1 Section 25G in DFW area Message-ID: Date: Tue, 8 Nov 2005 09:25:41 -0600 I found one. Tnx - W5GT "W5GT" wrote in message news:Lhpaf.55679$RG4.3204@fe05.lga... > Found a section - thanks > > Dave - W5GT > > "W5GT" wrote in message news:Fnr9f.7204$7s1.6016@fe04.lga... > > I need one section of 25G in the Dallas/Ft Worth area. Please contact me > at > > w5gt@arrl.net. > > > > Thanks > > > > Dave - W5GT > > > > > > Article: 219172 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: AM Commercial radio reception Date: Tue, 8 Nov 2005 15:26:24 +0000 (UTC) Message-ID: References: <6487-436C4D06-493@storefull-3252.bay.webtv.net> <436d6a27_3@news1.prserv.net> <43700313_1@news1.prserv.net> "Crazy George" wrote > I don't have an accurate number for the entire country, but here in the > local area, there is one clear channel station with a single radiator, a > half dozen two tower arrays, two 3 tower arrays, five 4 tower arrays that I > can recall off the top of my head. If you had asked a dozen years ago, I > could have been more accurate. I don't think we have any 5 or 6 radiator > arrays here locally, if so, I don't remember them. If my math is correct, > that is a 50-50 split, so maybe half have more than 2 towers. > ======================================= Thanks George, I am amazed at the number of multi-tower MF antennas in the US. As you say, they are necessary to prevent co-channel interference, day and night, between a large number of broadcasters in the more densely populated regions of your vast country. ( Antenna salesmen have had a field day.) It is also interesting that the whole system is technically regulated by State and/or Central Government. It is not just a free-for-all for newcomers. I imagine the revenue comes solely from advertisers. Which makes me wonder what percentage of program time is allocated to adverts. Are such matters also regulated? Are any broadcast stations State or City owned? In this (UK) relatively densely populated country things settled down about 20 years ago. Few MF antennas have more than one tower (or masts as we call them). Although there is much broadcasting at MF for individual cities, most broadcasting takes place at FM VHF where 'capture effects' reduce interference from co-channel transmitters. It may be of interest that the BBC, still the World's finest broadcasting system, including its overseas services, no longer owns any transmitting stations, Mrs Thatcher quietly sold them off to a private party. Do some Googles for who the eventual owners are? ---- Reg. Article: 219173 of rec.radio.amateur.antenna From: "W5GT" References: <4356b635$1@news.vo.lu> Subject: Re: Mythbusters: The G5RV on 12m Message-ID: Date: Tue, 8 Nov 2005 09:31:23 -0600 My G5RV works fine for me on 12M and 17M. Not a beam, but since it's only at 15', I'm happy. My IC756 does have a built in tuner, so I'm sure that helps. W5GT "Thierry" <-> wrote in message news:4356b635$1@news.vo.lu... > > "Cecil Moore" wrote in message > news:TsS4f.2685$BZ5.384@newssvr13.news.prodigy.com... > > The myth: "Contrary to oft stated views, the Classic G5RV is not > > an all band antenna, it: does not have acceptable feed performance > > on any WARC bands;" Quoted from: http://www.vk1od.net/G5RV/ > > > > 12m is a WARC band. The standard G5RV performs very well on 12m > > band. Therefore, the above statement is a myth. (Hey, this silly > > myth game is actually fun.) :-) > > I confirm. I used both G5RV and OCF for Dxing with as good results as on the > other bands. > > Thierry, ON4SKY > http://www.astrosurf.org/lombry/ > > > > -- > > 73, Cecil http://www.qsl.net/w5dxp > > > > Article: 219174 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Message-ID: Date: Tue, 08 Nov 2005 15:33:01 GMT Owen Duffy wrote: > Cecil Moore wrote: >>If 100m (325 feet) of ladder-line results in 6dB loss, then a more >>realistic 75 feet of ladder-line will result in about 1.4 dB of loss. > > Close, I make it 2.2dB. What matched line loss are you using? The wireman says that line has about 0.2 dB of matched line loss per 100 ft at 30 MHz. According to the chart in my ARRL Antenna Book, an SWR of 25:1 at the load would cause about 1.5 dB loss in 75 feet. >>... waiting for me to forget to cross an 'i' or dot a 't'. > > Cecil, people often employ long runs of open wire feed on HF ... Did you miss the humor? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219175 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Message-ID: Date: Tue, 08 Nov 2005 15:39:30 GMT Reg Edwards wrote: > The REAL problem is that very few people know the SWR on the > transmission line because the SWR meter doesn't measure it. > > Aren't you are fooling yourselves? A host of us use EZNEC and other modeling programs, like you publish, to estimate the SWR and therefore the losses. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219176 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer References: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> <4wObf.16054$dO2.12920@newssvr29.news.prodigy.net> Message-ID: Date: Tue, 08 Nov 2005 15:47:30 GMT Tam/WB2TT wrote: > "Cecil Moore" wrote: > >>Tam/WB2TT wrote: >>>Only thing I can add is that it eats batteries, ... >> >>I run mine off an external rechargable 12v YUASA battery. > > Never thought of that. I actually have a 12V, 7 AH Yuasa sitting on the file > cabinet. I would just have to keep it well charged. I use a 2Ah NP2-12 with a molex connector double-sided taped to the underside of the MFJ-259 and charge it with an Astron RS-20M. The battery is smaller than the MFJ and about 3/4" thick. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219177 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Naval connection? You qualify for RNARS membership! References: Message-ID: Date: Tue, 08 Nov 2005 15:53:26 GMT Mike wrote: > Royal Navy Does going down with the ship in a past life count? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219178 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: ladderline to coax adapter Date: Tue, 8 Nov 2005 15:58:02 +0000 (UTC) Message-ID: References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <4d3cf.11958$q%.10105@newssvr12.news.prodigy.com> > Guess I should have put a smiley face on my above posting. > Did you miss the humor? =============================== Cec, even as a foreigner I seldom miss your humor, smileys or not. Thank heavens, on the Internet, the English and American lanuages are drawing closely together. But I am still inclined to draw a distinction beween Americans and USA citizens. They are different! --- Reg. Article: 219179 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Mythbusters: The G5RV on 12m References: <4356b635$1@news.vo.lu> Message-ID: Date: Tue, 08 Nov 2005 16:04:22 GMT W5GT wrote: > My G5RV works fine for me on 12M and 17M. Not a beam, but since it's only at > 15', I'm happy. My IC756 does have a built in tuner, so I'm sure that helps. I had to increase the 450 ohm tuned section length on my G5RV to 36 feet to obtain a low 50 ohm SWR (no tuner) on 17m. EZNEC says the standard G5RV, with 1/2WL of 20m tuned section, will present an impedance of about 38-j270 to the coax with a resulting SWR of 40:1. That would be pretty lossy for 75 ft. of RG8X, maybe even lossy enough to make your IC756 happy. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219180 of rec.radio.amateur.antenna From: Edwin Johnson Subject: Re: Loop Antennas References: <11mvjfic11rdq9f@corp.supernews.com> Date: 08 Nov 2005 16:18:26 GMT Message-ID: <4370cfd2$0$1765$8b463f8a@news.nationwide.net> On 2005-11-08, Michael wrote: > Has anybody else had this experience with loops? It looks like I have room > to put up a triangular loop. Will this work as well? > > Can I use the same tuner I have now and just feed a coax into a balun. Or, > should I put the balun in the tuner and come straight out with ladder line? Following Walt's (W2DU) ideas, I have a 259' horizontal delta (triangle) loop (two trees and a wooden pole) fed at almost middle of one side (convenience, not design) by 450 ohm ladder line. This is soldered directly to a ferrite bead choke balun (ala W2DU) which, via PL-259s and barrel connector, goes to a very short piece of 50 ohm coax (about 6') directly into the house to the unbalanced SO-239 input of my MFJ-941E. Works like a charm on all bands 80-10m, no RF in the room, and good signal reports. ...Edwin, KD5ZLB -- _______________________________________________________ "Once you have flown, you will walk the earth with your eyes turned skyward, for there you have been, there you long to return."-- da Vinci ... www.shreve.net/~elj Article: 219181 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <4d3cf.11958$q%.10105@newssvr12.news.prodigy.com> Message-ID: Date: Tue, 08 Nov 2005 16:50:46 GMT Reg Edwards wrote: > Thank heavens, on the Internet, the English and American lanuages are > drawing closely together. But I am still inclined to draw a > distinction beween Americans and USA citizens. They are different! And Texans are even more so. Ours is the only state whose flag is allowed to be flown at an equal height with the US flag. (Some places around here fly the Texas flag an inch or so higher than that damned Yankee flag. :-) Texas was the only state having the legal right to seceed from the USA during the Civil War. The last battle of the Civil war was fought near Brownsville, TX and the South won. Reg, I saw a program on "The Discovery Channel: Ice Age Columbus: Who Were the First Americans?" It said, based on the latest arrowhead and tool archaeological evidence, that America was discovered by sea-going ice-age Europeans 17,000 years before Columbus made his voyage. It was asserted that some Native Americans still carry the genetic markers donated by those early Europeans. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219182 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: ladderline to coax adapter Message-ID: References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <4d3cf.11958$q%.10105@newssvr12.news.prodigy.com> Date: Tue, 08 Nov 2005 17:18:44 GMT On Tue, 08 Nov 2005 12:03:11 -0500, Amos Keag wrote: >Cecil Moore wrote: > >> Reg Edwards wrote: >> >>> Thank heavens, on the Internet, the English and American lanuages are >>> drawing closely together. But I am still inclined to draw a >>> distinction beween Americans and USA citizens. They are different! >> >> >> And Texans are even more so. > >SNIPPED: That great ICON of America, John Wayne of Blessed Memory, >asserted that the residents of Texas were TEXICANS! [Not Americans and >NOT citizens of USA]. How does this impact citizenship?? I believe Texas also used to be its own independent country, the Republic of Texas. Sam Houston was president. We were called Texians. (And John Wayne was not a Texian, Texican, Texan or any other deriviative.) Bob k5qwg > >Cecil, you opened a bag of Texas Nightcrawlers [Bass bait worms] with >your Texas comment. :-) > >AK > > Ours is the only state whose >> flag is allowed to be flown at an equal height with the >> US flag. (Some places around here fly the Texas flag an >> inch or so higher than that damned Yankee flag. :-) Texas >> was the only state having the legal right to seceed from >> the USA during the Civil War. The last battle of the Civil >> war was fought near Brownsville, TX and the South won. >> >> Reg, I saw a program on "The Discovery Channel: >> Ice Age Columbus: Who Were the First Americans?" It >> said, based on the latest arrowhead and tool archaeological >> evidence, that America was discovered by sea-going ice-age >> Europeans 17,000 years before Columbus made his voyage. It >> was asserted that some Native Americans still carry the >> genetic markers donated by those early Europeans. Article: 219183 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: AM Commercial radio reception References: <6487-436C4D06-493@storefull-3252.bay.webtv.net> <436d6a27_3@news1.prserv.net> <43700313_1@news1.prserv.net> <-qOdnSqYL_qXR-3enZ2dnUVZ_sWdnZ2d@comcast.com> Message-ID: <4%5cf.11986$q%.6396@newssvr12.news.prodigy.com> Date: Tue, 08 Nov 2005 18:19:44 GMT Amos Keag wrote: > Finally, the USA is succumbing to a creeping Socialism. This is contrary > to the words of John F Kennedy: "Ask NOT what your country can do for > you; ask what you can do for your country." Methinks you completely missed Kennedy's meaning. Here's Ayn Rand's take on that statement: "Ask NOT what your country can do for you ...", translation: Stop expecting the federal government to preserve and protect your individual constitutional rights; "... ask what you can do for your country.", translation: give up your constitutional rights, including your life, liberty, and possessions, in order to benefit the welfare state. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219184 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> Subject: Re: ladderline to coax adapter Date: Tue, 8 Nov 2005 13:23:46 -0500 Message-ID: I choose a ladderline length to always feed the antenna at a current node. "Owen Duffy" wrote in message news:nn70n1tcbbkthprk11dcv1hesqrpl7cksi@4ax.com... > On Mon, 7 Nov 2005 22:21:35 -0500, "Fred W4JLE" > wrote: > > >How many hams find a feedline length of 100 Meters acceptable? Lets look at > >a more realistic length of 100 feet and the loss is less than 2 dB at 30 > >Mhz. The loss is much less on the lower bands. With all due respect, your > >example sucks! > > BTW, I make your example 2.7dB, not less than 2dB. (Perhaps you labour > under the misaprehension that loss per unit length is a constant in > this situation). > > Fred, what you have highlighted is the unstated assumption of some > limit on length. You know enough to choose a length so that the ROT is > true, but does a learner soaking this up know as much? > > Owen > -- Article: 219185 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <4d3cf.11958$q%.10105@newssvr12.news.prodigy.com> Message-ID: Date: Tue, 08 Nov 2005 18:32:00 GMT Amos Keag wrote: > SNIPPED: That great ICON of America, John Wayne of Blessed Memory, > asserted that the residents of Texas were TEXICANS! [Not Americans and > NOT citizens of USA]. How does this impact citizenship?? Some Texans never wanted to join the United States and it was a close vote back when Texas was an independent country. Sam Houston was probably the deciding factor. If Texas had not joined the US, we probably would still have plenty of $60 a gallon oil. (Inside intel as opposed to Intel Inside(R)): I once worked for Schlumberger and Texas is definitely NOT out of oil, i.e. Lots of oil is being held in reserve in cases of arrested development as it is in Florida, California, and Alaska.) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219186 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> Message-ID: Date: Tue, 08 Nov 2005 18:39:18 GMT Fred W4JLE wrote: > I choose a ladderline length to always feed the antenna at a current node. And because a current node is guaranteed to occur at least every 1/2WL, an HF feedline need never be longer than 164 feet, Owen's 100 meter feedline notwithstanding. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219187 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: Antenna gain question Date: Tue, 08 Nov 2005 11:08:00 -0800 Message-ID: References: Richard Clark wrote: > On Mon, 07 Nov 2005 11:16:08 -0800, Jim Kelley > wrote: > > >>I think what you're seeing is the 3-D interference pattern generated by >>your sources. > > > Hi Jim, > > 3D in two-space? No. It was you who claimed to have modeled the antenna in three-space, was it not? Either way, in three-space or two, you have an interference pattern. That is the point. >>I'm not sure that really tells us very much about the antennas themselves. >>You'd need to surround each of the antennas with a >>uniform field in order to compare them. By uniform, I mean the field >>intensity toward the antenna is the same in any direction. > > > The problem has symmetry on its side, additional source add to the > dipole in equal measure to the yagi. Adding more power does not > create the missing power already lost. It would be silly to expect it to. How much power should you expect to measure with your instruments positioned in an interference null? This is the nature of your "leaky bucket". 73, ac6xg Article: 219188 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Antenna gain question References: Message-ID: <%O6cf.17150$dO2.8208@newssvr29.news.prodigy.net> Date: Tue, 08 Nov 2005 19:15:07 GMT Jim Kelley wrote: > Richard Clark wrote: >> 3D in two-space? No. > > It was you who claimed to have modeled the antenna in three-space, was > it not? Actually, if time appeared in the equations as in 2*pi*f*t, then it would be 3Dspace+1Dtime = 4D, no? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219189 of rec.radio.amateur.antenna From: "Michael" Subject: Re: Loop Antennas Date: Tue, 8 Nov 2005 20:26:08 -0800 Message-ID: <11n1ujn491vqd80@corp.supernews.com> References: <11mvjfic11rdq9f@corp.supernews.com> "Hal Rosser" wrote in message news:HCRbf.45698$ty1.39736@bignews1.bellsouth.net... > Ah yes grasshopper - zee loops - zay are good. > The loop helps reduce noise since its dc-shorted and no static buildup, > and your socks won't stick to it. ;-) > but it takes more trees to hold it up > > Oh thank you Master Rosser. I am a little wiser now. How long before I can take the pebble from your hand or maybe just kick butt? Article: 219190 of rec.radio.amateur.antenna From: "Rod Maupin" Subject: VHF Circularly Polarized Antenna, for local use? Date: Tue, 8 Nov 2005 11:27:15 -0800 Message-ID: <11n1v0jt9uov88@corp.supernews.com> I am planning how to set up my VHF/UHF station and I need some help. You can orient a VHF antenna horizontally for CW/SSB work or you could orient that same antenna vertically for local FM use. What if I am new to VHF/UHF and I want to do both. Could you get a circularly polarized antenna, with both horizontal and vertical elements and use it for both types? I don't want to buy two of the same antenna, only to have one horizontal and one vertical. What is your advice? Rod KI7CQ Article: 219191 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: VHF Circularly Polarized Antenna, for local use? References: <11n1v0jt9uov88@corp.supernews.com> Message-ID: Date: Tue, 08 Nov 2005 20:07:01 GMT Rod Maupin wrote: > What if I am new to VHF/UHF and I want to do both. Could you get a > circularly polarized antenna, with both horizontal and vertical elements and > use it for both types? I don't want to buy two of the same antenna, only to > have one horizontal and one vertical. Mount your beam antenna at 45 degrees to the vertical. You can work both and only lose half an S-unit. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219192 of rec.radio.amateur.antenna From: "Rod Maupin" Subject: Re: VHF Circularly Polarized Antenna, for local use? Date: Tue, 8 Nov 2005 12:15:31 -0800 Message-ID: <11n21r2apvbds06@corp.supernews.com> References: <11n1v0jt9uov88@corp.supernews.com> Thanks Cecil. That's great advice. Problem solved. Rod KI7CQ Article: 219193 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: AM Commercial radio reception Date: Tue, 8 Nov 2005 14:11:07 -0600 Message-ID: <23142-4371065B-1088@storefull-3258.bay.webtv.net> References: Reg, G4FGQ wrote: "It is also interesting that the whole system is technically regulated by State and/or Central Government." In the beginning, there was no regulation. There were only wireless experimenters. Marconi invented the antenna which made the signal go far. Marconi`s antenna may have been seen as an elevated capactor plate. When the transmitter and receiver were each equipped with a plate, you had a coupling capacitor with the earth for a return path. The capacitor carries displacement current while the earth moves electrons.. Then, Marconi discovered the capacitor leads worked well enough without the plates, so plates were omitted. Marconi was soon using wireless for ship to shore communications. It was essential to safety of life at sea. When the Titanic sank on April 15, 1912, it had a Marconi operator aboard. The world was immediately aware of radio. Inept radio communications during the loss of the Titanic prompted the U.S. Congress to pass the Radio Act of 1912, which expanded on the Wireless Ship Act of 1910 which required all seafaring vessels to maintain 24-hour radio watch and keep contact with nearby ships and coastal radio stations. All radio communications were in code until Reginald Fessenden invented wireless telephony in 1906. In the early wireless days a lidtener had to understand code to make sense of wireless. The Radio Act of 1912 assigned three-letter and four-letter codes (call-letters) to radio stations and limited broadcasting to 340 meters. This jammed the signals. From the beginning, the U.S. Federal Government declared sole jurisdiction over radio as the waves don`t stop at state lines and must involve international cooperation. It`s the "Interstate Commerce Regulation Power" of the Federal Government. In 1920, KDKA in Pittsburgh, a Westinghouse station, transmitted the first commercial radio broadcast. In 1922, the U.S. Commerce Department allowed powerful stations to use 400 meters, as long as they only broadcast music. In 1925, A,C. Nielsen began reporting audience shares to advertisers, In 1925, the first soap opera (The Smith Family) was broadcast. In 1926, RCA, General Electric, and Westinghouse established The National Broadcasting Company (NBC). NBC operated two networks of stations (Red & Blue). In 1929, William S. Paley founded The Columbia Broadcasting System (CBS). In 1931, there were 40,000 U.S. TV sets, including 4,000 in New York City. In 1933, Edwin Armstrong introduced Frequency Modulation. The Communications Act of 1934 created the Federal Communicationsd Commission which regulates broadcasting. In 1936, The British Broadcasting Corporation (BBC) debuted the world`s first television service with three hours of programming a day. In 1937, Edgar Bergen and Charlie MCCarthy debuted on NBC TV. We live in interesting times. Advertising pays for broadcasting in the U.S. except for some public support of non-commercial or almost non-commercial stations. Program time devoted to advertising on commercial stations was limited by the FCC to just a few minutes per hour before Carter became president. He started the deregulation process which has now run amok. Commercial announcements were the topic of "Saturday Night Live". Satirically, they entertain. Mrs. Thatcher may have sold the BBC`s distribution facilities, but since BBC has done so well programming, I hope the production facilities are still in the hands of those responsible and that they continue and grow their product. Who bought the BBC`s transmitters depends on how big the bargains were. If a windfall was readily available, I suspect the Queen, her relatives and allies may have been the buyers. Like Russia, I suppose, except with more care that the buyers seem not to be profiteers. My daughter lives in London and pays her tax to support the BBC. She now owns a 99-year lease on her flat in Westminster. Only leases are available. The right people are the ownwers and they aren`t selling. Her married name is Edwards too, but her husband is an American. They are both lawyers. Best regards, Richard harrison, KB5WZI Article: 219194 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> Date: Tue, 08 Nov 2005 21:30:28 GMT On Tue, 08 Nov 2005 15:33:01 GMT, Cecil Moore wrote: >Owen Duffy wrote: > >> Cecil Moore wrote: >>>If 100m (325 feet) of ladder-line results in 6dB loss, then a more >>>realistic 75 feet of ladder-line will result in about 1.4 dB of loss. >> >> Close, I make it 2.2dB. > >What matched line loss are you using? The wireman says that line >has about 0.2 dB of matched line loss per 100 ft at 30 MHz. According >to the chart in my ARRL Antenna Book, an SWR of 25:1 at the load >would cause about 1.5 dB loss in 75 feet. I am using Wes's characterisation of Wireman 551. Dan's TLDETAILS prog or my online calculator ( http://www.vk1od.net/tl/tllce.php ) both use (slightly different) models derived from Wes's published measurements. I don't have the ARRL Antenna Book with me at the moment, but I suspect it is not based on the same Matched Line Loss model, and does not estimate loss from the actual reflection coefficients but from an "average SWR" model which gives an averaged loss per unit length that doesn't take account of the fact that loss is usually highest in the region of current maxima. My calculator produces a figure of 2.2 dB for your example. I haven't rechecked Dan's this morning, but it is close. Grab Dan's calculator or mine and try it out. Dan's is really neat and a stand-alone Windows app, my online calc has less graphics, doesn't display (or even calculate SWR), knows about more transmission lines, and only needs a browser to access it. I use them both. In my 100m of W551 with a 16+j0 load at 30MHz, the loss in one metre of line nearest the load is over 4%, the good news is that since 75% of the transmitter power is already lost, the weighted effect of that 4.3% is nearer 1% of tx output. >>>... waiting for me to forget to cross an 'i' or dot a 't'. Of course I don't, otherwise I would have mentioned ...! >Did you miss the humor? Must have. 73 Owen -- Article: 219195 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Date: Tue, 08 Nov 2005 13:32:35 -0800 Message-ID: <11n26bm98889n34@corp.supernews.com> References: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> <11mvpqjme2l7ge0@corp.supernews.com> <0smdnetLAMKSpu3eRVn-pw@comcast.com> <11n13ejlg4b2o7b@corp.supernews.com> Tam/WB2TT wrote: > > Roy, > I wasn't too clear, but I have 2 T networks back/back. That makes the center > cap C/2. I am going to run SWCad on the Pi configuration later, and see what > that does. If you've cascaded two sections, you have two 1000 pF capacitors in parallel at the center. That makes a total value of 2000 pF at that point. Roy Lewallen, W7EL Article: 219196 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Date: Tue, 08 Nov 2005 13:41:29 -0800 Message-ID: <11n26sbptngij0f@corp.supernews.com> References: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> <11mvpqjme2l7ge0@corp.supernews.com> <0smdnetLAMKSpu3eRVn-pw@comcast.com> <11n13ejlg4b2o7b@corp.supernews.com> Tam/WB2TT wrote: > "Tam/WB2TT" wrote in message > news:i72dnQZzhvKvTu3eRVn-oA@comcast.com... > > Meanwhile, I measured the impedance of a Drake 100W dummy load with and > without the HPF. All readings without the HPF are within Drake spec. > > FREQ NO HPF With HPF > > 4 Mhz 47j2 33j13 > 7MHz 47j2 55j3 > 14MHz 47j1 50j7 > 28MHz 48j2 47j3 > 50MHz 49j2 54j11 > 144MHz 53j11 74j36 > > Everything was connected with UHF adapters, and no coax was used. Ignore the > VHF readings,. as the filter was not built that carefully. Capacitors are > mica (actual values 1000, 560, 1000), and inductors appear to be 68-2 > (2.2uH). > > If I get a chance later today, I will rewire it into the Pi configuration > with the same inductors. That's about what I'd expect. The increasing X with frequency is consistent with a small amount of series stray inductance which is unavoidable in the physical construction. It can be minimized, of course, by careful construction. A typical homebrew HF filter will begin becoming poor at VHF and above due to series self inductance of the capacitors and shunt self capacitance of the inductors, plus other effects. Component selection and layout can help a lot, but it might be necessary to cascade a VHF/UHF filter with the HF filter if very wideband rejection is necessary. A network analyzer or spectrum analyzer with tracking generator or noise generator are invaluable in solving those problems. Of course, the more stuff you put in the path, the more you're likely to disturb the measurement. Roy Lewallen, W7EL Article: 219197 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> Message-ID: <3facf.10465$D13.4942@newssvr11.news.prodigy.com> Date: Tue, 08 Nov 2005 23:09:51 GMT Owen Duffy wrote: > In my 100m of W551 with a 16+j0 load at 30MHz, the loss in one metre > of line nearest the load is over 4%, the good news is that since 75% > of the transmitter power is already lost, the weighted effect of that > 4.3% is nearer 1% of tx output. What the heck is one "metre"? Netscape says that is misspelled and probably should be corrected to "metro". Why aren't you guys on the English system? If the loss in each meter is 4%, wouldn't the loss in 100 meters be 400%? What am I missing? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219198 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: VHF Circularly Polarized Antenna, for local use? Message-ID: References: <11n1v0jt9uov88@corp.supernews.com> Date: Tue, 08 Nov 2005 23:15:59 GMT That works pretty good until the other guy is also at 45 to the world and 90 degrees to you! John Ferrell W8CCW On Tue, 08 Nov 2005 20:07:01 GMT, Cecil Moore wrote: >Rod Maupin wrote: >> What if I am new to VHF/UHF and I want to do both. Could you get a >> circularly polarized antenna, with both horizontal and vertical elements and >> use it for both types? I don't want to buy two of the same antenna, only to >> have one horizontal and one vertical. > >Mount your beam antenna at 45 degrees to the vertical. >You can work both and only lose half an S-unit. Article: 219199 of rec.radio.amateur.antenna Subject: Question about free space loss ... From: dougmc@frenzy.com (Doug McLaren) Message-ID: Date: Tue, 08 Nov 2005 23:19:09 GMT I've got what's probably a pretty basic question about free space loss. I suspect I already know the answer, but I'd like to verify it. The general formula for free space loss is given as -- 36.6 + 20LogD + 20LogF, where D is the distance in miles and F is the frequency in MHz. Obviously the units don't matter so much -- if you were to change the units, you'd just change the 36.6 value to something else. No problem. The distance component is obvious -- the power is spreading out. But what's the frequency component about? Why would increasing the frequency cause less power to be radiated? My guess is that the frequency factor is _strictly_ something to take into account the effective area/aperature of the receiving antenna, which gets smaller as the frequency increases? As a more real-world example, if you had a 10 foot diameter satellite dish, aimed directly at a satellite broadcasting (in all directions -- let's assume an isotropic antenna there) 10 watts at 2 GHz, it would receive (ignoring any losses due to the atmosphere) the same power >from the satellite if the satellite was broadcasting 10 watts at 200 GHz? (Our 10 foot dish is most definately not an isotropic antenna.) As a reference, I'm looking at http://people.deas.harvard.edu/~jones/es151/prop_models/propagation.htm and I'm just verifying my conclusions ... To use the knowledge I think I've learned to solve the problem I'm trying to figure out, if you've got something that transmits a certain amount of data per second at 50 MHz to a receiver that's 1 mile away, and you wanted to switch to a system that works at 5 GHz but uses the same bandwidth, blindly applying the FSL formula tells you that you'd need 40 dB more power, 10,000 times as much. (Let's assume that both antennas are both 1/2 wavelength dipoles of the appropriate length for both 50 MHz and 5 GHz -- not isotropic, but relatively close. My frequencies are arbitrary here, chosen just to have a nice ratio of 100.) But really, since the antenna receives less energy (due to it's smaller size, and it's intercepting less of the signal), the background noise received by it will be similarly reduced (let's also assume that the background noise intensity is the same at the two frequencies) and so it's just a matter of using a more sensitive receiver, at least until you get to the point where the background noise isn't the limiting factor, and instead the limiting factor is the noise generated by the receiver itself? That assuming all my assumptions are correct (and there's a lot of them, I know) there's little need to increase the transmitted power at all -- just increase the gain in the amplifier in the receiver? Am I missing something? AD5RH -- Doug McLaren, dougmc@frenzy.com One dollar, one vote. Article: 219200 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: VHF Circularly Polarized Antenna, for local use? Date: Wed, 09 Nov 2005 00:04:35 -0000 Message-ID: <11n2f8j2l93mq8f@corp.supernews.com> References: <11n1v0jt9uov88@corp.supernews.com> >That works pretty good until the other guy is also at 45 to the world >and 90 degrees to you! ... or is using a standard horizontal antenna, but happens to be located in the plane of your antenna. In this situation, he will "see" only the component of your antenna's radiation pattern - he'll be in a deep null for any horizontal radiation and may not hear you at all. Building an antenna which is omnidirectional, and which also has substantially equal horizontally- and vertically-polarized signal components over the full omni donut, is possible (commercial FM services do it) but seems to be tricky, expensive, and prone to being narrow-band. -- 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: 219201 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: VHF Circularly Polarized Antenna, for local use? References: <11n1v0jt9uov88@corp.supernews.com> Message-ID: Date: Wed, 09 Nov 2005 00:08:15 GMT John Ferrell wrote: > That works pretty good until the other guy is also at 45 to the world > and 90 degrees to you! When two pilots are trying to avoid a head-on collision, they both bank right. Is there a similar convention for slanted beams? :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219202 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: Antenna gain question Date: Tue, 08 Nov 2005 16:13:34 -0800 Message-ID: References: Richard Clark wrote: > On Tue, 08 Nov 2005 11:08:00 -0800, Jim Kelley > wrote: > > Hi Jim, > > >>Either way, in three-space or two, you have an interference >>pattern. That is the point. > > > The point being what? The observation of the pattern is simply that, > an observation. That a pattern exists is also hardly a revolutionary > concept. That it is the product of many sources does not preclude the > results as physics allows a wave to be viewed as a continuum of > sources along its length. The typical radiation pattern which would ordinarily illuminate an antenna does not have an array of 'holes' in it - symmetrical or otherwise. Further, you can't expect to compare the performance of two different antennas when the field you're exposing them to is malformed and non-uniform. The result would be convoluted (as you have shown). > This leaky bucket is not fixed by > placing it outside of the "null" (ironically it was very near in a > peak); It is fixed by creating a uniform field. As I said before, integrating the results from a large number of individual point sources (rather than superposing the fields from a large array of point sources) would not produce an interference pattern. > hence an interference pattern is immaterial to the loss of > power as both designs suffer the same pattern - and equally I might > point out, if other arguments are consistently applied that equal > powers should be exhibited. This is apparently incorrect, as both antennas should produce the same result. One wouldn't have to do as much handwaving and fast talking if the field was uniform, Richard. 73, ac6xg Article: 219203 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> Message-ID: Date: Wed, 09 Nov 2005 00:25:59 GMT Amos Keag wrote: > Cecil Moore wrote: >> If the loss in each meter is 4%, wouldn't the loss in 100 meters >> be 400%? What am I missing? > > C'mon Cecil, you know it's an exponential decay. The maximum HF current point could exist in the first foot of feedline at the source. Why would the HF losses in the transmission line at the load ever be greater than at that maximum HF current point? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219204 of rec.radio.amateur.antenna From: "Tom" References: Subject: Re: Question about free space loss ... Message-ID: <6Tccf.19055$Ny6.1526@trnddc06> Date: Wed, 09 Nov 2005 02:09:06 GMT Yes - the common path loss formula includes the antenna gain. The gain of an antenna is defined as 4*PI*Ae/lambda^2. The effective aperture (Ae) of the antenna has units of square meters, the units of lambda^2 are square meters, so the wavelength dependence just normalizes area in terms of the wavelength. Otherwise the definition of antenna gain would change with frequency. That is, a dipole's gain would double everytime the freuqency was doubled, but that's not how we define antenna gain. We define the gain of a dipole to be independent of frequency. Path loss depends on antenna gain, 1/lambda^2 can be translated to f^2/c^2, thus the dependency of path loss on f. -- Tom "Doug McLaren" wrote in message news:Nnacf.82574$GQ.4637@tornado.texas.rr.com... > I've got what's probably a pretty basic question about free space > loss. I suspect I already know the answer, but I'd like to verify it. > > The general formula for free space loss is given as -- > > 36.6 + 20LogD + 20LogF, where D is the distance in miles and F is > the frequency in MHz. > > Obviously the units don't matter so much -- if you were to change the > units, you'd just change the 36.6 value to something else. No problem. > > The distance component is obvious -- the power is spreading out. > > But what's the frequency component about? Why would increasing the > frequency cause less power to be radiated? > > My guess is that the frequency factor is _strictly_ something to take > into account the effective area/aperature of the receiving antenna, > which gets smaller as the frequency increases? > > As a more real-world example, if you had a 10 foot diameter satellite > dish, aimed directly at a satellite broadcasting (in all directions -- > let's assume an isotropic antenna there) 10 watts at 2 GHz, it would > receive (ignoring any losses due to the atmosphere) the same power > from the satellite if the satellite was broadcasting 10 watts at 200 > GHz? > > (Our 10 foot dish is most definately not an isotropic antenna.) > > As a reference, I'm looking at > http://people.deas.harvard.edu/~jones/es151/prop_models/propagation.htm > and I'm just verifying my conclusions ... > > To use the knowledge I think I've learned to solve the problem I'm > trying to figure out, if you've got something that transmits a certain > amount of data per second at 50 MHz to a receiver that's 1 mile away, > and you wanted to switch to a system that works at 5 GHz but uses the > same bandwidth, blindly applying the FSL formula tells you that you'd > need 40 dB more power, 10,000 times as much. > > (Let's assume that both antennas are both 1/2 wavelength dipoles of > the appropriate length for both 50 MHz and 5 GHz -- not isotropic, but > relatively close. My frequencies are arbitrary here, chosen just to > have a nice ratio of 100.) > > But really, since the antenna receives less energy (due to it's > smaller size, and it's intercepting less of the signal), the > background noise received by it will be similarly reduced (let's also > assume that the background noise intensity is the same at the two > frequencies) and so it's just a matter of using a more sensitive > receiver, at least until you get to the point where the background > noise isn't the limiting factor, and instead the limiting factor is > the noise generated by the receiver itself? That assuming all my > assumptions are correct (and there's a lot of them, I know) there's > little need to increase the transmitted power at all -- just increase > the gain in the amplifier in the receiver? > > Am I missing something? > > AD5RH > > -- > Doug McLaren, dougmc@frenzy.com One dollar, one > vote. Article: 219205 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> Subject: Re: ladderline to coax adapter Date: Tue, 8 Nov 2005 21:33:46 -0500 Message-ID: <37665$43716070$97d56a33$8122@ALLTEL.NET> At the same time velocity factors were converted to furlongs per fortnight... :>) "Amos Keag" wrote in message news:jcydnSPeVqwNpezenZ2dnUVZ_tydnZ2d@comcast.com... > I just started reading this thread. Is the loss in a 'per meter' or 'per > wavelength'? In the olden days, we quoted loss as Nepers per > wavelength. When did it change to 'percent per meter'? > > AK > Article: 219206 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: <0ip2n1t3j3ld1dgobl5utufff0ip0er980@4ax.com> References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> Date: Wed, 09 Nov 2005 03:25:47 GMT On Tue, 08 Nov 2005 23:09:51 GMT, Cecil Moore wrote: >Owen Duffy wrote: >> In my 100m of W551 with a 16+j0 load at 30MHz, the loss in one metre >> of line nearest the load is over 4%, the good news is that since 75% >> of the transmitter power is already lost, the weighted effect of that >> 4.3% is nearer 1% of tx output. > >What the heck is one "metre"? Netscape says that is misspelled and >probably should be corrected to "metro". Why aren't you guys on >the English system? Metre: The fundamental base of the metre is the quarter of the terrestrial meridian, or the distance from the pole to equator, which has been divided into ten millions of equal parts, one of which is of the length of the metre. I think we saw the light before the English, but I think they have a partial metrication now. >If the loss in each meter is 4%, wouldn't the loss in 100 meters >be 400%? What am I missing? I did not say "the loss in each meter is 4%", I said "the loss in one metre of line nearest the load is over 4%". Firstly, percentage losses on cascaded sections are not additive... you know that. Losses multiply, dB losses add because adding exponents is multiply the fundamental quantity. As I have said before, you seem to be under the misconception that the overall loss (ie Pin/Pout) per unit length of a transmission line operating with VSWR>1 is constant, It is not necessarily a constant. It is for a lossless cable, and I think it probably is for a distortionless cable... but I would have to check that. (It is true that the loss per unit length of a transmission line operating with VSWR=1 is constant.) We were discussing an example based on Wireman 551 ladder-line. The dominant factor affecting loss at 30MHz is the series resistance element. Does it make sense that since in that example, the magnitude of the current varies by nearly 25:1 along the line, that the I**2*R loss per unit length along the line is not constant, and will vary by a factor approaching 625:1? Owen -- Article: 219207 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> <0ip2n1t3j3ld1dgobl5utufff0ip0er980@4ax.com> Message-ID: Date: Wed, 09 Nov 2005 05:46:00 GMT Owen Duffy wrote: > We were discussing an example based on Wireman 551 ladder-line. The > dominant factor affecting loss at 30MHz is the series resistance > element. Does it make sense that since in that example, the magnitude > of the current varies by nearly 25:1 along the line, that the I**2*R > loss per unit length along the line is not constant, and will vary by > a factor approaching 625:1? 25% of the power is delivered to the load. There are eleven current maximum points in 100m on 10m. Does that 11% of the feedline really contribute 59% of the losses? Does the remaining 89% of the feedline really only contribute 41% of the losses? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219208 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> Date: Wed, 09 Nov 2005 08:52:10 GMT On Tue, 8 Nov 2005 13:23:46 -0500, "Fred W4JLE" wrote: >I choose a ladderline length to always feed the antenna at a current node. > I don't know what this really means, and how it is relevant to the discussion that the ROT in question doesn't hold true for longer feed line lengths. You have previously dismissed 100m of feed line with the eloquent "sucks" comment, whatever that means. What has feeding an antenna at the current node got to do with feed line length? Is it intended to imply that feed line length or the ROT are not relevant when you feed the antenna at a current node? Is it just a trite comment to consume bandwidth? Owen >"Owen Duffy" wrote in message >news:nn70n1tcbbkthprk11dcv1hesqrpl7cksi@4ax.com... >> On Mon, 7 Nov 2005 22:21:35 -0500, "Fred W4JLE" >> wrote: >> >> >How many hams find a feedline length of 100 Meters acceptable? Lets look >at >> >a more realistic length of 100 feet and the loss is less than 2 dB at 30 >> >Mhz. The loss is much less on the lower bands. With all due respect, your >> >example sucks! >> >> BTW, I make your example 2.7dB, not less than 2dB. (Perhaps you labour >> under the misaprehension that loss per unit length is a constant in >> this situation). >> >> Fred, what you have highlighted is the unstated assumption of some >> limit on length. You know enough to choose a length so that the ROT is >> true, but does a learner soaking this up know as much? >> -- Article: 219210 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: MFJ-269 Antenna/SWR/RF Analyzer Date: Wed, 09 Nov 2005 04:04:50 -0800 Message-ID: <11n3pf4mpq95f8b@corp.supernews.com> References: <1noum19ctnsod6eu3dk1cnh9pdoav82121@4ax.com> <11mvpqjme2l7ge0@corp.supernews.com> <0smdnetLAMKSpu3eRVn-pw@comcast.com> <11n13ejlg4b2o7b@corp.supernews.com> <11n26bm98889n34@corp.supernews.com> Tam/WB2TT wrote: > > It's a high pass filter to reject the AM broadcast band. So, the two 1000 PF > caps are in series. Am I missing something? > Sorry, I missed that you had made a T network rather than pi. In general, a tee network substituted for a pi will have the same characteristics only at one frequency, but will have different transfer and/or impedance characteristics at other frequencies. So the substitution should be done with care if characteristics are important at more than one frequency. In this case, though, if you make a tee network which has the same "half wave" characteristic as the pi at the design frequency, it'll have identical transfer characteristics (it's got the same filter response) and complementary impedance characteristics. That is, at frequencies where one network has an input impedance greater than 50 ohms, the other will have an impedance that's less, and the phase angles are the negatives of each other. And, luckily, the transformation is simple for this particular special case -- the T network reactances are also all the same and also equal to the Z0 of the "transmission line". So one is just as good as the other. The HPF equivalent doesn't of course simulate a transmission line, although the impedance transformation though the filter is unity at the design frequency. Otherwise, it works in pretty much an opposite way >from the LPF. I need to correct and clarify a couple of points I made in my earlier posting. The "half wave" lowpass filter simulates a half wavelength transmission line only at and near the design frequency (where the reactances are all the same). It doesn't do a very good job either above or below that frequency(*). The 7 MHz example terminated with 50 ohms will show an input impedance within 2 ohms magnitude and 2 degrees phase of 50 ohms between about 6.2 and 7.4 MHz, so it's good for the entire 40 meter band. But it will disturb measurements on lower bands. You should construct one for each band and, preferably, one for each general impedance level you expect to measure. A single one won't do for multiple bands as I implied. (*)For a better general simulation of a *short* transmission line, use a ladder network with all the reactances equal to Z0 except the end components. For the end components, make the series L or shunt C half the value of the rest. (For example, the LPF I showed would have input and output shunt capacitors with reactance = 100 ohms, and remaining components with reactance = 50 ohms. A five-component tee type network would have input and output series inductors with reactance = 25 ohms, and the remaining components with reactance = 50 ohms.) This model improves -- in theory at least -- as more sections are added, being able to imitate longer and longer lines. In practice, imperfection in the components limits the quality of the approximation. But I don't think this is of particular interest in making analyzer measurements. The model I proposed is better for simulating a half wavelength line while providing filtering. Roy Lewallen, W7EL Article: 219211 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> <0ip2n1t3j3ld1dgobl5utufff0ip0er980@4ax.com> Message-ID: Date: Wed, 09 Nov 2005 14:46:07 GMT Owen Duffy wrote: > http://www.vk1od.net/lost/W551Example.htm > > Is the shape of the curve (the cyclic variation over each electrical > half wave diminishing away from the load, and the general shape of the > curve a surprise? The effects plotted here might not be explained by > the ARRL charts. The graph is unclear. What does it mean that 6% loss occurs at 100 neters? Is that 6% loss per meter at the source? There's 4% loss at 50 meters. Does that mean the average loss per meter is 4%? Where is the 4% loss in the meter closest to the load plotted? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219212 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> Message-ID: Date: Wed, 09 Nov 2005 15:02:35 GMT Owen Duffy wrote: > What has feeding an antenna at the current node got to do with feed > line length? Feedline length for an average system may be about 75 ft., the distance from the antenna to the transceiver. If a current maximum point occurs at 87 ft., make the feedline 87 ft. long with (usually) no tuner required. I assume what Fred thinks sucks is your implication that the average ham feeds his antenna with 100 meters of feedline. What percentage of hams do you think actually use 100 meters of transmission line? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219213 of rec.radio.amateur.antenna From: "Michael" Subject: Re: Loop Antennas Date: Wed, 9 Nov 2005 20:48:41 -0800 Message-ID: <11n47fl21h8li6e@corp.supernews.com> References: <11mvjfic11rdq9f@corp.supernews.com> I appreciate all the comments very much. A folded dipole would be easier for me. I will discuss this with my neighbor W0BBN. He has been using a loop for 20 years. It sounds like it is hard to go wrong if you are willing to put out the work for a loop antenna. I have been away from low band work since I started college. That has been very very long ago. I had never hear of a loop antenna back in the 50s. There was no internet and other hams were few and far between where I lived in the country. Article: 219214 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: <9je4n19quflv2043oh4s6ihv41qvvljhk9@4ax.com> References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> <0ip2n1t3j3ld1dgobl5utufff0ip0er980@4ax.com> Date: Wed, 09 Nov 2005 18:57:22 GMT On Wed, 09 Nov 2005 14:46:07 GMT, Cecil Moore wrote: >Owen Duffy wrote: >> http://www.vk1od.net/lost/W551Example.htm >> >> Is the shape of the curve (the cyclic variation over each electrical >> half wave diminishing away from the load, and the general shape of the >> curve a surprise? The effects plotted here might not be explained by >> the ARRL charts. > >The graph is unclear. What does it mean that 6% loss occurs at >100 neters? Is that 6% loss per meter at the source? There's 4% >loss at 50 meters. Does that mean the average loss per meter is >4%? Where is the 4% loss in the meter closest to the load plotted? The loss scale is in dB, it is the loss in dB at position x metres >from the load. If you examine the graph, you will find that the slope of the loss vs position line is as high as about -22dB/100m at the load, it has a minimum slope of close to 0dB/100m, and you can see that at large x, the slope approaches the matched line loss of -1dB/100m. (You find the -22dB/100m by using a ruler to scale off the slope. -22dB/100m is -0.22dB/m, or 10**-0.022 which is 0.9506, which corresponds to a loss of almost 5% in that one metre of line nearest the load. These aren't mental gymnastics!) You could calculate an average loss per meter figure, but I don't know what you could you use it for? The fact that this line is not straight (as some people seem to assume) means that working with average numbers is inherently inaccurate. Owen -- Article: 219215 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> Date: Wed, 09 Nov 2005 18:57:46 GMT On Wed, 09 Nov 2005 15:02:35 GMT, Cecil Moore wrote: >Owen Duffy wrote: >> What has feeding an antenna at the current node got to do with feed >> line length? > >Feedline length for an average system may be about 75 ft., >the distance from the antenna to the transceiver. If a >current maximum point occurs at 87 ft., make the feedline >87 ft. long with (usually) no tuner required. Well, I guess you are guessing at what Fred meant. But such a current maximum on the feed point repeats every electrical half wave, and such an approach doesn't preclude using feed lines much longer than 75 feet. > >I assume what Fred thinks sucks is your implication that the >average ham feeds his antenna with 100 meters of feedline. That is his misinterpretation if that is the case. I did not say an "average ham", but I assert that it is not all that uncommon to have a ham antenna located at 100m or more, and the ROT falls down. Thing is, about averages, is that the detail you throw away to calculate the average may have been relevant. Further, there is little consolation to the guy who has 10dB worse than average performance because he has used longer feed line under your ROT, to know that a whole lot of guys using shorter feed line are enjoying better than average performance and on average, it all balances out. It is quite feasible to place an antenna at longer distances if you want, but ladder line should be operated at lower VSWR for acceptable losses, or better feed line used... and the ROT doesn't say that. It is the unstated length assumption (of apparently 75') of your ROT that makes limits its validity to the people who are most likely to lap it up. What is an "average ham" now days? Is it one that doesn't have a real interest in the technical side of the hobby, the "I just wanna talk on the radio" set... they like ROTs, gives them something to parrot on air. Owen -- Article: 219216 of rec.radio.amateur.antenna From: Bob Miller Subject: Front end overload Message-ID: <2hi4n1hotfouennu2fi77j3fs136douuqc@4ax.com> Date: Wed, 09 Nov 2005 19:17:41 GMT If I have two rigs on two different antennas that pass within inches of each other, should I worry about front end overload or burnout on the rig not in use, even if it is off? (The two rigs are an Icom 735, about 100 watts out, and a TenTec 1320, about 4 watts out.) Tnx, Bob k5qwg Article: 219217 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: 900MHz antenna at sea surface Date: Wed, 09 Nov 2005 11:49:40 -0800 Message-ID: <11n4kmp7vgftmc3@corp.supernews.com> References: <1130962168.655457.263840@f14g2000cwb.googlegroups.com> <10021-436A3544-176@storefull-3251.bay.webtv.net> <1131039043.785167.82020@g44g2000cwa.googlegroups.com> <1131057506.111016.316920@g14g2000cwa.googlegroups.com> <11mnserb5miuj86@corp.supernews.com> <1131562771.102947.7060@o13g2000cwo.googlegroups.com> jmorash wrote: > Thanks Roy! I think I understand baluns quite a bit better now. Seems > like, indeed, a couple ferrite beads could make quite a difference to > my radiation pattern. > > This question is for Roy or anyone else who might know the answer: what > tool(s) do I want to try and gauge how good of an antenna I've built? > An SWR meter? Do they make those for 900 MHz? What else? An SWR meter doesn't measure antenna goodness. The only thing it tells you is how close the antenna's impedance is to 50 ohms, which has nothing to do with the important measures of its performance such as gain and pattern. The best test instrument is a low power transmitter and field strength meter, one at each end of a simulated communication link. For the other end of the link, it would be best to use a setup typical of what you'll actually be using in the field. You'll be able to get some idea of the antenna's effectiveness with over-ground tests, but the ultimate test will be the strength of the signal received over water with the antenna mounted as it will be for the real application. Precise quantitative measurement isn't trivial at all, but qualitative relative measurements are fairly easily made. Roy Lewallen, W7EL Article: 219218 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: Antenna gain question Date: Wed, 09 Nov 2005 12:31:31 -0800 Message-ID: References: Richard Clark wrote: > On Tue, 08 Nov 2005 16:13:34 -0800, Jim Kelley > wrote: > > >>It is fixed by creating a uniform field. As I said before, integrating >>the results from a large number of individual point sources (rather than >>superposing the fields from a large array of point sources) would not >>produce an interference pattern. > > > Hi Jim, > > Here you are clearly wrong in some presumption. For one, I have done > exactly as you have demanded should be done and you find an error. I > have responded several times to this identical complaint you've > offered, and you have neither offered what that error is, or where I > differ from what you insist in integrating the results. It seems to > me in performing it exactly as you describe it, that I have very > little choice in that matter anyway and barring further elaboration in > how my fulfilling your imperative differs from your imperative, your > point remains rather elusive. You forgot to write - Harumph! ;-) If you'll read back, you'll find that the descriptions you've provided of your model are far less than effusive and illuminating. No more than a few partial or incomprehensible sentences were provided. We're left to guess most of the details of what you have done. I can only deduce some of it from the results you have provided. I made no criticism of this. You spoke of symmetries and lost power without mention of their nature. So I mentioned their nature. It should have been obvious, but you hadn't even alluded to a possible explanation for this "lost power". BTW, single sources do not produce interference patterns (unless somehow you're inadvertantly causing diffraction somewhere between the source and the antenna). Each individual source will provide a signal. The amplitude and phase of the signal rendered in the antenna from a single source will depend the position of the source relative to the orientation and construction of the antenna. Summing all the individual signals rendered in the antenna from a multitude of individuals sources does not create an interference pattern in 3 space. It produces a simple magnitude and phase which would hypothetically appear in the antenna if an incoming uniform 'spherical field' existed. > However, let's just cut to the chase in that you are clearly disturbed > by this "interference pattern" that the tool so clearly reveals. I don't find interference to be disturbing. I'm simply pointing out that we shouldn't expect textbook results from antennas that are positioned amidst interfering sources. I'm sorry to have perturbed you with my comments and observations. Any criticisms you may have precieved should have been taken as purely constructive to the task. That is my only intent. 73, ac6xg Article: 219219 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <0IMbf.2543$fB2.1804@bignews2.bellsouth.net> <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> Subject: Re: ladderline to coax adapter Date: Wed, 9 Nov 2005 16:14:20 -0500 Message-ID: Hardly trite, it limits the line length to a maximum of 164 feet. "Owen Duffy" wrote in message news:0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com... > On Tue, 8 Nov 2005 13:23:46 -0500, "Fred W4JLE" > wrote: > > >I choose a ladderline length to always feed the antenna at a current node. > > > > I don't know what this really means, and how it is relevant to the > discussion that the ROT in question doesn't hold true for longer feed > line lengths. > > You have previously dismissed 100m of feed line with the eloquent > "sucks" comment, whatever that means. > > What has feeding an antenna at the current node got to do with feed > line length? Is it intended to imply that feed line length or the ROT > are not relevant when you feed the antenna at a current node? > > Is it just a trite comment to consume bandwidth? > > Owen > > >"Owen Duffy" wrote in message > >news:nn70n1tcbbkthprk11dcv1hesqrpl7cksi@4ax.com... > >> On Mon, 7 Nov 2005 22:21:35 -0500, "Fred W4JLE" > >> wrote: > >> > >> >How many hams find a feedline length of 100 Meters acceptable? Lets look > >at > >> >a more realistic length of 100 feet and the loss is less than 2 dB at 30 > >> >Mhz. The loss is much less on the lower bands. With all due respect, your > >> >example sucks! > >> > >> BTW, I make your example 2.7dB, not less than 2dB. (Perhaps you labour > >> under the misaprehension that loss per unit length is a constant in > >> this situation). > >> > >> Fred, what you have highlighted is the unstated assumption of some > >> limit on length. You know enough to choose a length so that the ROT is > >> true, but does a learner soaking this up know as much? > >> > -- Article: 219220 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> <0ip2n1t3j3ld1dgobl5utufff0ip0er980@4ax.com> <9je4n19quflv2043oh4s6ihv41qvvljhk9@4ax.com> Message-ID: <0Tvcf.25607$6e1.5815@newssvr14.news.prodigy.com> Date: Wed, 09 Nov 2005 23:46:04 GMT Owen Duffy wrote: > The loss scale is in dB, it is the loss in dB at position x metres > from the load. Aha, I see that noted at the bottom now that I scroll down. It didn't make sense to me if the loss scale was in percent. So what do I get if I integrate the area under the curve? Incidentally, I was engaging in fuzzy republican thinking when I came up with eleven current maximum points in 100 meters of feedline. Of course, there are twice that, i.e. 22 current maximum points which can be counted on your graph. > You could calculate an average loss per meter figure, but I don't know > what you could you use it for? The fact that this line is not straight > (as some people seem to assume) means that working with average > numbers is inherently inaccurate. Owen, most hams are not rocket scientists like you :-) Quite often, a rule-of-thumb average beats total ignorance. All measurements contain errors and are inherently inaccurate. Some of us live with that reality. Some of us rant and rave about it. Next time you are on your motorcycle, note that your speedometer is "inherently inaccurate" as is your gas gauge as are your reflexes. If you are not inherently inaccurate throwing darts in the local pub, you are a very unusual homo sapien. I, for one, am satisfied with average losses, presumably averaged over one half wavelength. The way I came up with that 25:1 limit on my open-wire SWR is that 600/25 equals 24 ohms and that is an acceptable impedance to my IC-256PRO's autotuner. Noting that the losses in 100 ft. of open-wire line running at an SWR of 25:1 are acceptable was an afterthought. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219221 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> Message-ID: Date: Thu, 10 Nov 2005 00:08:51 GMT Owen Duffy wrote: > Well, I guess you are guessing at what Fred meant. Nope, not a guess. Fred and I are on the same wavelength. :-) We use the same "notuner" method for resonating our antenna systems. > That is his misinterpretation if that is the case. I did not say an > "average ham", but I assert that it is not all that uncommon to have a > ham antenna located at 100m or more, and the ROT falls down. But it is indeed extremely uncommon for an *American* amateur radio operator to have a feedline that is 100m long. I personally know of only a handfull of cases in my 55 years of hamming and most of those involved getting vhf/uhf antennas to the top of a hill. > Thing is, about averages, is that the detail you throw away to > calculate the average may have been relevant. It may be relevant to a "rocket scientist", such as yourself, and completely irrelevant and indeed beyond the understanding of the average ham who must necessarily rely upon rules of thumb. > It is quite feasible to place an antenna at longer distances if you > want, ... ~99.99% of hams don't want to. Why make things more difficult? > It is the unstated length assumption (of apparently 75') of your ROT > that makes limits its validity to the people who are most likely to > lap it up. Sorry to disagree, the great majority of "people who are most likely to lap it up" are people with 60-100 foot feedlines. Most assertions on this newsgroup are in the context of the average ham. Owen, it's obvious that you deliberately picked 100 meters to try to prove a point that you couldn't make otherwise. You chose an inferior ladder-line that I wouldn't even allow on my property. Your attempts to save face by dragging the discussion down some primrose path involving minute details is interesting but not interesting enough to follow you down said path. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219222 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Antenna gain question References: Message-ID: Date: Thu, 10 Nov 2005 00:11:27 GMT Jim Kelley wrote: > Any criticisms you may have > precieved should have been taken as purely constructive to the task. Richard probably considers you input to be constructive interference. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219223 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Loop Antennas References: <11mvjfic11rdq9f@corp.supernews.com> <11n47fl21h8li6e@corp.supernews.com> Message-ID: <6jwcf.25613$6e1.25176@newssvr14.news.prodigy.com> Date: Thu, 10 Nov 2005 00:16:02 GMT Michael wrote: > I had never hear of a loop antenna back in the 50s. Loops started to come into their own with the invention by C. C. Moore of the Cubical Quad circa 1939. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219224 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> Date: Thu, 10 Nov 2005 00:32:48 GMT On Thu, 10 Nov 2005 00:08:51 GMT, Cecil Moore wrote: >Owen, it's obvious that you deliberately picked 100 meters to try to >prove a point that you couldn't make otherwise. You chose an inferior >ladder-line that I wouldn't even allow on my property. Your attempts to >save face by dragging the discussion down some primrose path involving >minute details is interesting but not interesting enough to follow >you down said path. I chose 100m as a round number that is practical and long enough to demonstrate that at very high VSWR, the approximations that might hold for shorter lengths and lower VSWR are no longer valid. Open wire feeders well in excess of 100m are practical, but ladder line with very high VSWR isn't. (On the other hand, your 75' "standard" is about enough to reach the feed point of a medium height antenna directly above the shack, and might be argued as a minimum practical length for a good antenna.) The ladder line I chose was one of the four that have reasonably good characterisation (by N7WS) and it wouldn't matter much which of the four you chose, they are fairly similar... I chose the first one on the list. (The last one on the list, 554 with 25:1 load SWR give 5.6dB against 6dB or 551... I wont bother checking the others.) No, I did not deliberately choose an inferior ladder line. Owen -- Article: 219225 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Front end overload Message-ID: References: <2hi4n1hotfouennu2fi77j3fs136douuqc@4ax.com> <1dKdnRH9istMAe_enZ2dnUVZ_sqdnZ2d@comcast.com> Date: Thu, 10 Nov 2005 01:42:16 GMT On Wed, 9 Nov 2005 20:07:13 -0500, "Tam/WB2TT" wrote: > >"Bob Miller" wrote in message >news:2hi4n1hotfouennu2fi77j3fs136douuqc@4ax.com... >> If I have two rigs on two different antennas that pass within inches >> of each other, should I worry about front end overload or burnout on >> the rig not in use, even if it is off? >> >> (The two rigs are an Icom 735, about 100 watts out, and a TenTec 1320, >> about 4 watts out.) >> >> Tnx, >> >> Bob >> k5qwg >> >> >Fire up the Icom, and connect a meter and dummy load to the other coax. I >once saw 10W. > >Tam/WB2TT > I don't have an a-la-carte dummy load to try that test, but I'll take your word for it :-) Thanks, bob k5qwg Article: 219226 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: ladderline to coax adapter References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> Message-ID: Date: Thu, 10 Nov 2005 02:27:49 GMT Owen Duffy wrote: > I chose 100m as a round number that is practical ... 328.1 feet is NOT a round number. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 219227 of rec.radio.amateur.antenna From: "John, N9JG" References: <11mvjfic11rdq9f@corp.supernews.com> <11n47fl21h8li6e@corp.supernews.com> <6jwcf.25613$6e1.25176@newssvr14.news.prodigy.com> Subject: Re: Loop Antennas Message-ID: Date: Thu, 10 Nov 2005 02:48:23 GMT See this link for some more info http://lists.contesting.com/archives/html/Towertalk/2002-11/msg00393.html "Cecil Moore" wrote in message news:6jwcf.25613$6e1.25176@newssvr14.news.prodigy.com... > Michael wrote: > >> I had never hear of a loop antenna back in the 50s. > > Loops started to come into their own with the invention > by C. C. Moore of the Cubical Quad circa 1939. > -- > 73, Cecil http://www.qsl.net/w5dxp Article: 219228 of rec.radio.amateur.antenna Message-ID: <43735DAA.29880426@spamless.com> From: jimbo Subject: Re: Tape Measure Yagi Antenna Questions References: <1131565742.060922.169080@g14g2000cwa.googlegroups.com> Date: Thu, 10 Nov 2005 14:48:12 GMT hi kevin, Since you're interested in a 2 element yagi for reception only, how about a Moxon antenna ? You can use aluminum rod and pvc, takes up less space then the Yagi but almost same performance. Or try it with the tape measure for elements. Direct fed with 50 ohm coax. http://www.cebik.com/moxon/moxbld.html Here is a calculator to help build a Moxon for a given frequency. http://www.cebik.com/moxon/moxpage.html Good luck! jimbo Article: 219229 of rec.radio.amateur.antenna From: "AAA RF Products" Subject: Coax Connector, Adapter, & Bulk Cable Catalog Message-ID: Date: Thu, 10 Nov 2005 09:24:17 -0800 For your free copy of our new catalog, please email sales@AAARFProducts.com or see www.aaarfproducts.com No minimum order. No handling charges. High quality and low cost. Article: 219230 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: Antenna gain question Date: Thu, 10 Nov 2005 09:25:46 -0800 Message-ID: References: Cecil Moore wrote: > Jim Kelley wrote: > >> Any criticisms you may have precieved should have been taken as purely >> constructive to the task. > > > Richard probably considers your input to be constructive interference. :-) Then it wasn't for naught. We've finally landed upon something that you and Richard can agree upon. ;-) 73, Jim AC6XG Article: 219231 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: AM Commercial radio reception Date: Thu, 10 Nov 2005 11:26:13 -0600 Message-ID: <29588-437382B5-228@storefull-3254.bay.webtv.net> References: Richard Clark, KB7QHC wrote: "---by A. Frederick Collins inventor of the Wireless Telephone, 1899." Collins apparently connected an arc lamp to an arial and ground, using a microphone transmitter to modulate the oscillations it set up. I suppose a carbon button in series with the d-c to the arc would do that. Success has many authors. The airplane had many builders around this productive era, but it is the Wright brothers that are credited with the first practical success. Fessenden was a Canadian who happened to be Chief Engineer of the Radio Corporation of America, successor to the American Marconi Company. Fessenden holds more patents than aqnyone except Thomas Edison, who once employed Fessenden. Fessenden`s modulation method was control of the excitation of an r-f alternator by a magnetic amplifier which he modulated with audio, speech, music or whatever, even dots and dashes. Modulation of high r-f powers was commonplace. Hundreds of kilowatts were produced and modulated by the Fessenden method. A relic of the era in Sweeden is still revived annually for demonstration, I believe. Best regards, Richard Harrison, KB5WZI Article: 219232 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: ladderline to coax adapter Date: Thu, 10 Nov 2005 10:35:49 -0800 Message-ID: References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <998ee$43701a24$97d56a33$13066@ALLTEL.NET> <0vd3n19mdn73gd3srojq4ijoa65tgb2sgp@4ax.com> Owen Duffy wrote: > (On the other hand, your 75' "standard" is about enough to reach the > feed point of a medium height antenna directly above the shack, and > might be argued as a minimum practical length for a good antenna.) As opposed to the standard full height backyard antenna with 100 meter feedline which would then be something more like this: http://www.kkn.net/gallery/hcjb/hc15 ;-) ac6xg Article: 219233 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: fmt Date: Thu, 10 Nov 2005 18:12:27 -0500 Message-ID: <11n7ktuncrro4e9@corp.supernews.com> References: Years ago, I was faculty advisor of a thesis containing a viable technique for measuring the carrier of a SSB signal modulated by a human voice when the carrier was nulled. The student's name, as well as I can remember, was Day and his first name was something like Louis. Should be a link to it somewhere. The scheme took advantage of the nature of the human voice. It required one to have the means to inject a carrier (which was measured by conventional means) and to look at the recovered audio on a scope. The old FMT had one measure CW signals. They were great fun. 73 Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Richard Clark" wrote in message news:jbt6n11j7ouc4m4ddieeaorliju81gspmv@4ax.com... > On Thu, 10 Nov 2005 10:06:56 GMT, ml wrote: > >I'd love to learn and try it, but didn't see any posted > >''instructions''... > > >Participants may utilize either direct or indirect techniques to > >determine the tone frequency. ''Direct measurements assume a carrier > >frequency and measure the audio tone frequency directly,'' Silver > >explains. ''Indirect measurements obtain the transmitted frequency of > >the tone component at RF, then compute the difference between the > >published carrier frequency and measured frequency.'' > > Hi Myles, > > You don't see instructions because you are supposed to work this out > for yourself and then report both your results and HOW YOU DID IT. > > It should be a slam dunk with a PC sound card being run under an FFT. > However, the skill part is tuning the sideband (and then it remains > only the skill of reading the frequency setting of your rig - any > error is probably going to be there). > > 73's > Richard Clark, KB7QHC Article: 219234 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: fmt Date: Thu, 10 Nov 2005 18:26:38 -0500 Message-ID: <11n7loiiljqs9af@corp.supernews.com> References: <11n7ktuncrro4e9@corp.supernews.com> Here is the title and author's name: A method for accurate receiver tuning and precise measurement of the carrier frequency of voice-modulated, suppressed-carrier, single-sideband radio signals Day, Lucius Boyden. I do not know where it might be read on the WEB. 73 Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "J. Mc Laughlin" wrote in message news:11n7ktuncrro4e9@corp.supernews.com... > Years ago, I was faculty advisor of a thesis containing a viable technique > for measuring the carrier of a SSB signal modulated by a human voice when > the carrier was nulled. The student's name, as well as I can remember, was > Day and his first name was something like Louis. > > Should be a link to it somewhere. > > The scheme took advantage of the nature of the human voice. It required one > to have the means to inject a carrier (which was measured by conventional > means) and to look at the recovered audio on a scope. > > The old FMT had one measure CW signals. They were great fun. > > 73 Mac N8TT > > -- > J. Mc Laughlin; Michigan U.S.A. > Home: JCM@Power-Net.Net > "Richard Clark" wrote in message > news:jbt6n11j7ouc4m4ddieeaorliju81gspmv@4ax.com... > > On Thu, 10 Nov 2005 10:06:56 GMT, ml wrote: > > >I'd love to learn and try it, but didn't see any posted > > >''instructions''... > > > > >Participants may utilize either direct or indirect techniques to > > >determine the tone frequency. ''Direct measurements assume a carrier > > >frequency and measure the audio tone frequency directly,'' Silver > > >explains. ''Indirect measurements obtain the transmitted frequency of > > >the tone component at RF, then compute the difference between the > > >published carrier frequency and measured frequency.'' > > > > Hi Myles, > > > > You don't see instructions because you are supposed to work this out > > for yourself and then report both your results and HOW YOU DID IT. > > > > It should be a slam dunk with a PC sound card being run under an FFT. > > However, the skill part is tuning the sideband (and then it remains > > only the skill of reading the frequency setting of your rig - any > > error is probably going to be there). > > > > 73's > > Richard Clark, KB7QHC > > Article: 219235 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: fmt Message-ID: References: Date: Fri, 11 Nov 2005 00:29:19 GMT On Thu, 10 Nov 2005 10:06:56 GMT, ml wrote: >hi > >I noticed the below lately and wonder, being new at this ... how one >would measure it? > >is their a step by step guide or just a specific instrument(s) you need > >I'd love to learn and try it, but didn't see any posted >''instructions''... >any help appreciated This looks like a guessing game / lottery to some extent, since no information is given on the stability of either the virtual carrier or the modulating tone (yet you are advised they both may vary) and the time of measurement (an instant?) is part of the submitted data. The winner using a sound scientific approach to measurement may require luck to be not beaten by a less accurate, but closer answer at some moment. Owen > > >m > > >partially cut from the arrl's email >"Returning to the airwaves November 17 at 0245 UTC (Wednesday, >November 16 in US time zones), the 2005 ARRL Frequency Measuring >Test (FMT) once again will call on participants to measure the >frequency of an audio tone modulating the carrier. > >''Measuring the tone frequency, as opposed to that of the carrier, >reinforces the understanding of the relationship between carrier >frequency and the actual components of a transmitted signal,'' >Engineer and ARRL Contributing Editor Ward Silver, N0AX, says in >''Tune In the 2005 Frequency Measuring Test,'' in November QST (p >54),...www.arrl.org/w1aw/fmt/2005/05fmtsilver.pdf. ''With the carrier >largely suppressed for SSB signals, only the sideband components >remain. A single modulating tone results in a single transmitted >component.'' But, Silver notes, the frequency of the absent carrier >is what the operator sees on the radio's display. > >The FMT signals will emanate from Maxim Memorial Station W1AW this >year on 160, 80 and 40 meters. The 20-meter transmission has been >dropped for 2005 because of the generally poor conditions during >evening hours on that band. The frequencies will be 1855, 3990 and >7290 kHz, and all transmissions will be on lower sideband (LSB). The >FMT will replace the W1AW phone bulletin normally transmitted at >0245 UTC on November 17 (November 16 in US time zones). > >Participants may utilize either direct or indirect techniques to >determine the tone frequency. ''Direct measurements assume a carrier >frequency and measure the audio tone frequency directly,'' Silver >explains. ''Indirect measurements obtain the transmitted frequency of >the tone component at RF, then compute the difference between the >published carrier frequency and measured frequency.'' > >Silver advises that since the W1AW exciters are independent units >and not fed with a single local oscillator, participants can expect >the measured tone frequency to differ slightly on each band. > >The test itself will consist of three 60-second tone transmissions >on each band, followed by a station identification. The whole test >will run for about 15 minutes and will end with a station ID. > >Submitted reports should include the time of reception and the tone >frequency. Those using an indirect measurement method should show >how they calculated the tone frequency. Participants also should >include name, call sign and location in their reports, and they may >submit separate reports for each band. A Certificate of >Participation is available to all entrants. -- Article: 219236 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: fmt Date: Thu, 10 Nov 2005 17:26:57 -0800 Message-ID: References: <11n7ktuncrro4e9@corp.supernews.com> <11n7loiiljqs9af@corp.supernews.com> J. Mc Laughlin wrote: > Here is the title and author's name: > A method for accurate receiver tuning and precise measurement of the carrier > frequency of voice-modulated, suppressed-carrier, single-sideband radio > signals > Day, Lucius Boyden. > > I do not know where it might be read on the WEB. 73 Mac N8TT > -- > J. Mc Laughlin; Michigan U.S.A. > Home: JCM@Power-Net.Net No hits in the UC library system, unfortunately. jk > "J. Mc Laughlin" wrote in message > news:11n7ktuncrro4e9@corp.supernews.com... > >>Years ago, I was faculty advisor of a thesis containing a viable technique >>for measuring the carrier of a SSB signal modulated by a human voice when >>the carrier was nulled. The student's name, as well as I can remember, > > was > >>Day and his first name was something like Louis. >> >>Should be a link to it somewhere. >> >>The scheme took advantage of the nature of the human voice. It required > > one > >>to have the means to inject a carrier (which was measured by conventional >>means) and to look at the recovered audio on a scope. >> >> The old FMT had one measure CW signals. They were great fun. >> >> 73 Mac N8TT >> >>-- >>J. Mc Laughlin; Michigan U.S.A. >>Home: JCM@Power-Net.Net >>"Richard Clark" wrote in message >>news:jbt6n11j7ouc4m4ddieeaorliju81gspmv@4ax.com... >> >>>On Thu, 10 Nov 2005 10:06:56 GMT, ml wrote: >>> >>>>I'd love to learn and try it, but didn't see any posted >>>>''instructions''... >>> >>>>Participants may utilize either direct or indirect techniques to >>>>determine the tone frequency. ''Direct measurements assume a carrier >>>>frequency and measure the audio tone frequency directly,'' Silver >>>>explains. ''Indirect measurements obtain the transmitted frequency of >>>>the tone component at RF, then compute the difference between the >>>>published carrier frequency and measured frequency.'' >>> >>>Hi Myles, >>> >>>You don't see instructions because you are supposed to work this out >>>for yourself and then report both your results and HOW YOU DID IT. >>> >>>It should be a slam dunk with a PC sound card being run under an FFT. >>>However, the skill part is tuning the sideband (and then it remains >>>only the skill of reading the frequency setting of your rig - any >>>error is probably going to be there). >>> >>>73's >>>Richard Clark, KB7QHC >> >> > > Article: 219237 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: fmt Date: Thu, 10 Nov 2005 23:34:39 -0500 Message-ID: <11n87q37p6rp1fa@corp.supernews.com> References: <11n7ktuncrro4e9@corp.supernews.com> <11n7loiiljqs9af@corp.supernews.com> Dear Richard: I too have given it a good try without much success. I think that I gave my (paper) copy to our library long ago. It probably disappeared is one of many purges. The Naval Postgraduate School indicates that they have two paper copies. I will try to remember details. The scheme worked. It just occurred to me to check for a Radio Amateur license: DAY JR, LUCIUS B, W5ZJZ (General) 10306 W IDAHO PL LAKEWOOD, CO 80232-5019 His age is about right. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Richard Clark" wrote in message news:k2q7n15h0ami0pdrt1324ionhavmeg5fk2@4ax.com... > On Thu, 10 Nov 2005 18:26:38 -0500, "J. Mc Laughlin" > wrote: > > >Here is the title and author's name: > >A method for accurate receiver tuning and precise measurement of the carrier > >frequency of voice-modulated, suppressed-carrier, single-sideband radio > >signals > > Day, Lucius Boyden. > > > > I do not know where it might be read on the WEB. 73 Mac N8TT > > Hi Mac, > > With a name like that, a search against it should have more success > than I have encountered (which is to say none). Wish I could have > done better. > > 73's > Richard Clark, KB7QHC Article: 219238 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: fmt Date: Thu, 10 Nov 2005 23:37:37 -0500 Message-ID: <11n87vk5rtpu892@corp.supernews.com> References: <11n7ktuncrro4e9@corp.supernews.com> <11n7loiiljqs9af@corp.supernews.com> Dear Jim: Thanks for looking. I am surprised as he was in California at the time, as well as I remember. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Jim Kelley" wrote in message news:dl0s11$imv$1@news.service.uci.edu... > > > J. Mc Laughlin wrote: > > > Here is the title and author's name: > > A method for accurate receiver tuning and precise measurement of the carrier > > frequency of voice-modulated, suppressed-carrier, single-sideband radio > > signals > > Day, Lucius Boyden. > > > > I do not know where it might be read on the WEB. 73 Mac N8TT > > -- > > J. Mc Laughlin; Michigan U.S.A. > > Home: JCM@Power-Net.Net > > No hits in the UC library system, unfortunately. > > jk > > > "J. Mc Laughlin" wrote in message > > news:11n7ktuncrro4e9@corp.supernews.com... > > > >>Years ago, I was faculty advisor of a thesis containing a viable technique > >>for measuring the carrier of a SSB signal modulated by a human voice when > >>the carrier was nulled. The student's name, as well as I can remember, > > > > was > > > >>Day and his first name was something like Louis. > >> > >>Should be a link to it somewhere. > >> > >>The scheme took advantage of the nature of the human voice. It required > > > > one > > > >>to have the means to inject a carrier (which was measured by conventional > >>means) and to look at the recovered audio on a scope. > >> > >> The old FMT had one measure CW signals. They were great fun. > >> > >> 73 Mac N8TT > >> > >>-- > >>J. Mc Laughlin; Michigan U.S.A. > >>Home: JCM@Power-Net.Net Article: 219239 of rec.radio.amateur.antenna From: "Jeff Dieterle" Subject: Am reception Date: Fri, 11 Nov 2005 09:35:15 -0500 Message-ID: <11n9b1ak6fquaaa@corp.supernews.com> Pardon me if this is the wrong group to find some answers. I'm using a GE Superadio III and would like to receive 2 frequencies. AM670 from Chicago and AM1070 from Indianapolis predominantly night time listening. I work inside a factory and can't receive either of these unless I get near an outside window or go outside. I'm considering buying a tuned loop for these 2 frequencies from http://www.amradioantennas.com/. He's quoted me a price of 85 us$ including shipping and insurance. Does anyone have experience with this type of tuned loop antennae. I've ran RGU-6 coax from my office to the factory roof, (appx.75ft) as I doubt if the loop would pull these in from inside my office which is inside the factory. Is there a less expensive alternative than the loop since I have coax installed ? Thanks Jeff Article: 219240 of rec.radio.amateur.antenna From: 'Doc Subject: Re: Am reception References: <11n9b1ak6fquaaa@corp.supernews.com> Message-ID: Date: Fri, 11 Nov 2005 14:47:40 GMT Jeff, I think the first thing I'd try would be to just add a length of wire to the end of the cable on the roof. If It does any good, add a longer length of wire and see what happens. Is it a 'cure-all'? Nope, but certainly easier/cheaper/faster than getting a loop antenna... 'Doc Article: 219241 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Am reception References: <11n9b1ak6fquaaa@corp.supernews.com> Message-ID: Date: Fri, 11 Nov 2005 16:03:54 GMT Jeff Dieterle wrote: > Is there a less expensive alternative than the loop since I have coax > installed ? Just tie an external wire to the coax center conductor and try it - may not work but it doesn't cost much to try. -- 73, Cecil, http://www.qsl.net/w5dxp Article: 219242 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Am reception Message-ID: References: <11n9b1ak6fquaaa@corp.supernews.com> Date: Fri, 11 Nov 2005 16:45:10 GMT On Fri, 11 Nov 2005 09:35:15 -0500, "Jeff Dieterle" wrote: >Pardon me if this is the wrong group to find some answers. I'm using a GE >Superadio III and would like to receive 2 frequencies. AM670 from Chicago >and AM1070 from Indianapolis predominantly night time listening. I work >inside a factory and can't receive either of these unless I get near an >outside window or go outside. > >I'm considering buying a tuned loop for these 2 frequencies from >http://www.amradioantennas.com/. He's quoted me a price of 85 us$ including >shipping and insurance. Does anyone have experience with this type of tuned >loop antennae. I have a similar loop from C.Crane company. It works well. But these loops need to be in close proximity to the radio's built-in antenna. Simply putting the loop up on the roof at the end of the coax won't do any good. Using the loop indoors, inside the factory, would be a crap shoot... don't think it would be worth the $85. I'd look at some sort of outdoor antenna, as others have suggested. bob k5qwg > I've ran RGU-6 coax from my office to the factory roof, >(appx.75ft) as I doubt if the loop would pull these in from inside my office >which is inside the factory. > >Is there a less expensive alternative than the loop since I have coax >installed ? > >Thanks >Jeff > Article: 219243 of rec.radio.amateur.antenna From: "Jerry Martes" References: <11n9b1ak6fquaaa@corp.supernews.com> Subject: Re: Am reception Message-ID: Date: Fri, 11 Nov 2005 17:00:18 GMT "Jeff Dieterle" wrote in message news:11n9b1ak6fquaaa@corp.supernews.com... > Pardon me if this is the wrong group to find some answers. I'm using a GE > Superadio III and would like to receive 2 frequencies. AM670 from Chicago > and AM1070 from Indianapolis predominantly night time listening. I work > inside a factory and can't receive either of these unless I get near an > outside window or go outside. > > I'm considering buying a tuned loop for these 2 frequencies from > http://www.amradioantennas.com/. He's quoted me a price of 85 us$ > including shipping and insurance. Does anyone have experience with this > type of tuned loop antennae. I've ran RGU-6 coax from my office to the > factory roof, (appx.75ft) as I doubt if the loop would pull these in from > inside my office which is inside the factory. > > Is there a less expensive alternative than the loop since I have coax > installed ? > > Thanks > Jeff Hi Jeff The 75 feet of coax between the outside antenna and the radio will also be a capacitor shunting the signal to ground across the front end of the receiver. That can be a serious loss of signal at AM frequencies. An amplifier on the roof is one solution. It is fairly easy to build a loop so that concept can be evaluated prior to spending the $85. You are aware that the tuned loop on the roof will require the antenna to be adjusted for each of the two frequencies you want. Is that practical for your application? Jerry Article: 219244 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Rick Littlefield K1BQT article on feeding extended double zepps Date: Fri, 11 Nov 2005 19:36:56 -0000 Message-ID: <11n9smon2j6q5d8@corp.supernews.com> References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> Does anybody have a copy of K1BQT's article from the Summer 1997 issue of Communications Quarterly, on a method for constructing a 2-meter extended double zepp antenna with a novel feed/matching arrangement? If so, can I get a scanned copy somehow? advTHANKSance! -- 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: 219245 of rec.radio.amateur.antenna From: nospam@nouce.bellatlantic.net Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps Message-ID: References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> Date: Fri, 11 Nov 2005 22:43:27 GMT On Fri, 11 Nov 2005 19:36:56 -0000, dplatt@radagast.org (Dave Platt) wrote: >Does anybody have a copy of K1BQT's article from the Summer 1997 issue >of Communications Quarterly, on a method for constructing a 2-meter >extended double zepp antenna with a novel feed/matching arrangement? >If so, can I get a scanned copy somehow? > >advTHANKSance! I dont have the article but Mr Cebik has written about it and how it works. www.cebik.com/edz/edzfeed.html I built a version for 6m and it's very good for simple wire and it also resonates as a dipole at 17m. Allison Article: 219246 of rec.radio.amateur.antenna From: "Rod Maupin" Subject: Re: VHF Circularly Polarized Antenna, for local use? Date: Tue, 8 Nov 2005 16:11:58 -0800 Message-ID: <11n2fn7bt737q86@corp.supernews.com> References: <11n1v0jt9uov88@corp.supernews.com> <11n2f8j2l93mq8f@corp.supernews.com> Perhaps I should try it vertically for a while and then horizontally for a while, see which way I like the best, and then leave it at that polarization. Rod KI7CQ Article: 219247 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: ladderline to coax adapter Message-ID: <5053n1t3os3532p71kb68hjkvoi3p2n2i3@4ax.com> References: <9fqvm19qvhkoo9eamga4qbh2ubhf8h7ko4@4ax.com> <8452n1degk9a850g91ph5gsd2ad8tdejei@4ax.com> <3facf.10465$D13.4942@newssvr11.news.prodigy.com> <0ip2n1t3j3ld1dgobl5utufff0ip0er980@4ax.com> Date: Wed, 09 Nov 2005 06:18:45 GMT On Wed, 09 Nov 2005 05:46:00 GMT, Cecil Moore wrote: >Owen Duffy wrote: >> We were discussing an example based on Wireman 551 ladder-line. The >> dominant factor affecting loss at 30MHz is the series resistance >> element. Does it make sense that since in that example, the magnitude >> of the current varies by nearly 25:1 along the line, that the I**2*R >> loss per unit length along the line is not constant, and will vary by >> a factor approaching 625:1? > >25% of the power is delivered to the load. There are eleven current >maximum points in 100m on 10m. Does that 11% of the feedline really >contribute 59% of the losses? Does the remaining 89% of the feedline >really only contribute 41% of the losses? When I have written about loss per unit length, I have implied "loss at the rate of y per unit length". If you have tried to apply the 4+% figure to one meter at each maximum, then you are unlikely to get any meaningful results for a number of reasons. See the graph I just posted (our posts crossed in the mail so to speak). I haven't stated it it the post, but it should be obvious that the rate of attenuation is the slope of the line in the plot referenced in the post. Owen -- Article: 219248 of rec.radio.amateur.antenna From: Walter Maxwell Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps Message-ID: <73gan1tsu86k3ddf3k3sc0eism1imc6pbf@4ax.com> References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> Date: Sat, 12 Nov 2005 01:10:25 GMT On Fri, 11 Nov 2005 19:36:56 -0000, dplatt@radagast.org (Dave Platt) wrote: >Does anybody have a copy of K1BQT's article from the Summer 1997 issue >of Communications Quarterly, on a method for constructing a 2-meter >extended double zepp antenna with a novel feed/matching arrangement? >If so, can I get a scanned copy somehow? > >advTHANKSance! Hi Dave, I have the CommQuart issue that has Rick's article. However, it's the Fall issue, not the summer. I'm in the process of scanning it for you. Give me a few minutes. Is the mail address shown above the correct one for email? Walt, W2DU Article: 219249 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps Date: Sat, 12 Nov 2005 01:35:12 -0000 Message-ID: <11nahmge5b43ndc@corp.supernews.com> References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> <73gan1tsu86k3ddf3k3sc0eism1imc6pbf@4ax.com> >Hi Dave, > >I have the CommQuart issue that has Rick's article. However, it's the Fall >issue, not the summer. I'm in the process of scanning it for you. Give me a few >minutes. Is the mail address shown above the correct one for email? Hi, Walt! I just received the article I was thinking of (pages 104 and 106 of the Summer '97 Communications Quarterly) from another ham. If that's the same article you have, then no need to send it. If there's another version in the Fall '97 issue which is different, then I'd love to have it as well. The EDZ described in the Summer issue is an interesting one. It's a lot lighter in weight than the only other 2-meter EDZ plans I've seen (the latter being a copper-pipe variety with a different matching and balun arrangement). Both look like useful designs, although since they're long and require side-mounting from a mast or tower they're probably less convenient for home use than ground-plane or J-pole antennas. Yes, my email address is correct. -- 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: 219251 of rec.radio.amateur.antenna From: "Nick Kennedy" References: <11n7ktuncrro4e9@corp.supernews.com> <11n7loiiljqs9af@corp.supernews.com> Subject: Re: fmt Message-ID: Date: Fri, 11 Nov 2005 21:04:05 -0600 "J. Mc Laughlin" wrote in message news:11n7loiiljqs9af@corp.supernews.com... > Here is the title and author's name: > A method for accurate receiver tuning and precise measurement of the carrier > frequency of voice-modulated, suppressed-carrier, single-sideband radio > signals > Day, Lucius Boyden. > > I do not know where it might be read on the WEB. 73 Mac N8TT It sounds similar to a recent article. I see that in the July/August QEX there was an article called "A Blind Automatic Frequency Control Algorithm for Single Sideband" by Geissinger. I can't find that issue, so don't know it used Mr. Day's technique or not. 73--Nick, WA5BDU Article: 219252 of rec.radio.amateur.antenna Message-ID: <31303030383738354374A68294@zetnet.co.uk> Date: Fri, 11 Nov 2005 14:11:14 GMT From: Dave Piggin Subject: Re: Coax Connector, Adapter, & Bulk Cable Catalog References: > For your free copy of our new catalog, please email sales@AAARFProducts.com > or see www.aaarfproducts.com > No minimum order. > No handling charges. > High quality and low cost. Still waiting for mine from the beginning of the year, and my promised disc. I wont hold my breath though. -- Amateur Radio Call Sign M1BTI, Located in Manchester England. Locator square IO83TK Chairman Of Trafford Radio Club. Club Call Signs G0TRG & M1BBP Located at Umist, University Of Manchester Institute For Science And Technology Share What You Know, Learn What You Dont. Article: 219253 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: fmt Date: Sat, 12 Nov 2005 08:50:39 -0500 Message-ID: <11nbsoiiua7d8e5@corp.supernews.com> References: <11n7ktuncrro4e9@corp.supernews.com> <11n7loiiljqs9af@corp.supernews.com> Dear Nick: Fascinating. When you find the QEX article please report back. 73 Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Nick Kennedy" wrote in message news:BWcdf.2375$ih5.1677@dukeread11... > "J. Mc Laughlin" wrote in message > news:11n7loiiljqs9af@corp.supernews.com... > > Here is the title and author's name: > > A method for accurate receiver tuning and precise measurement of the > carrier > > frequency of voice-modulated, suppressed-carrier, single-sideband radio > > signals > > Day, Lucius Boyden. > > > > I do not know where it might be read on the WEB. 73 Mac N8TT > > > It sounds similar to a recent article. I see that in the July/August QEX > there was an article called "A Blind Automatic Frequency Control Algorithm > for Single Sideband" by Geissinger. I can't find that issue, so don't know > it used Mr. Day's technique or not. > > 73--Nick, WA5BDU > > Article: 219254 of rec.radio.amateur.antenna From: Mike Luther Subject: Re: 1/4 vertical antenna height Date: Sat, 12 Nov 2005 17:29:35 +0000 Message-ID: <11nc9k5k5cqsu0e@corp.supernews.com> References: <1131755996.202107.98090@z14g2000cwz.googlegroups.com> Chuck Chuck W. wrote: > Is there any major advantage of mounting a Butternut vertical on top of > my house which would put it around 45 feet versus ground mounting it? > Seems like for years I've worked lots of stations with ground mounted > verticals. So long as I've got lots of radials I would have a low > angle of radiation, yes? > > Thanks, > > Chuck > W1CEW > I have used elevated 4-square vertical arrays and elevated verticals for years on 40 and 80 meters. Performance seems just fine on them. However one very serious issue remains, as far as my experience is concerned, for using them. You, MUST provide some decent lighting protection for them as to how to avoid the step voltage that appears on the whole system because of the elevated radial and feed point positions above ground during strikes and even nearby hits. Even a ten foot height above ground for a 40 meter vertical, with four tuned elevated radials at that height, is a huge voltage point up from true ground, considering the large RF currents in the strike. If your feed line is in any position to be involved in that elevated voltage position and can carry part of the strike dissapation back into your shack or home, you can really get hurt. I found out a long time ago, that the best way to protect my equipment with elevated HF verticals is to carry the entire feed system back to ground level where I can incorporate Polyphaser or other gas tube protection at that same ground level I'm using to sink the strike at the arrays. Then I bring the feed line back to the physical structure at GROUND level with appropriate protection at the structure site entrance, sinked to ground as well there. Since incorporating that technique, for many years now, and I take an average of a direct hit on my 80 meter array at least once every year or so, I never have lost anything on the HF station, even though it is on line 24X7 all the time, and some parts of it are remote operatable as well. With complete pig iron equipped industrial rack computer systems and so on, even they have survived completely for years now that way too. But not switching power supply stuff, as I've found out sadly. I take more damage, whatever, from direct hits on the neighboring power lines that sink back to my facility good ground systems, at this point. The worst damage for years is oddly on the phone system lines. Even with protection at the entrance point, there is still enough inductace ramp-up on these low level circuits, that I'll see blown fuses in the phone line protectors from time to time, and rarely, even yet, modem failures, even with that done! Again, my best advice if you want to go your way with the big elevated vertical, is to carefully consider how to mitigate the strike effects for not only your ham gear, but the rest of the dwelling as well. Remember, even ten or twenty feet is a real length for getting surge voltage, when true ground is underneath it. And where things are connected at a junction point which can carry part of the surge current off on a 'parallel' path to a different ground sink point you might not have considered. W5WQN Article: 219255 of rec.radio.amateur.antenna From: "W4WNT" References: <11mvjfic11rdq9f@corp.supernews.com> Subject: Re: Loop Antennas Message-ID: Date: Sat, 12 Nov 2005 17:56:57 GMT The loop is a DC short and is very quiet. You can also feed it with a quarter wave section of 75 ohm coax using (quarter wave length x Velocity of coax) as the length of the matching section. Good luck, Bill, W4WNT "Michael" wrote in message news:11mvjfic11rdq9f@corp.supernews.com... >I get a lot of noise from my random wire antenna. It transmits very well >but is very noisy in receive. My neighbor put up a 280 foot loop antenna >which he feeds with ladder line. He feeds the ladder line from a 4 to 1 >balun to coax. The coax comes from a tuner. His setup performs very well on >all bands down to 75 meters. I went over to his shack last night and >listened to his receiver on 75. I was really impressed with the lack of >noise. I can safely say the difference in noise was profound. He has this >loop surrounding his house at a 30 ft. height. It is arranged in a square. > > Has anybody else had this experience with loops? It looks like I have room > to put up a triangular loop. Will this work as well? > > Can I use the same tuner I have now and just feed a coax into a balun. Or, > should I put the balun in the tuner and come straight out with ladder > line? There is a lot of room in this tuner. It is an old remote controlled > tuner surplused from a ship. > Article: 219256 of rec.radio.amateur.antenna From: "CA" References: <1131755996.202107.98090@z14g2000cwz.googlegroups.com> <11nc9k5k5cqsu0e@corp.supernews.com> Subject: Re: 1/4 vertical antenna height Message-ID: Date: Sat, 12 Nov 2005 18:37:24 GMT "Mike Luther" skrev i meddelandet news:11nc9k5k5cqsu0e@corp.supernews.com... > Chuck > > Chuck W. wrote: >> Is there any major advantage of mounting a Butternut vertical on top of >> my house which would put it around 45 feet versus ground mounting it? >> Seems like for years I've worked lots of stations with ground mounted >> verticals. So long as I've got lots of radials I would have a low >> angle of radiation, yes? >> >> Thanks, >> >> Chuck >> W1CEW >> Check this page: http://www.qsl.net/df3lp/projects/vertical/index.html "Do not mount groundplane antennas at heights between 0.25 and 1.25 wavelength. At those levels above ground most of the energy will be radiated at angles of 27° to 45° into the ionosphere. This phenomenon seems to be independent to the number of radials or other counterpoises. Further simulations indicates that this is true for all other variants of vertical antenna systems too. " 73 SM6PXJ Chris Article: 219257 of rec.radio.amateur.antenna Subject: Isotron antennas From: Dave Oldridge Message-ID: Date: Sat, 12 Nov 2005 18:59:30 GMT I've been seeing pictures of these weird antennas for years. Near as I can tell from the picture, it's essentially a heavily-loaded very short dipole with two large capacity hats at the ends. But it's impossible to tell from the pictures what the exact configuration is. Can anyone tell me exactly what's happening? Is the mast part of the radiating system? The feedline? The literature (including the manuals) sort of implies that it is. Also, from the pictures, I get the impression that the standard mast-mount configuration is mostly vertically polarized. This would certainly account for reports I have read that the antenna is a bit of a dud at short range on 80m. If someone has a computer model for it for MMHAMSOFT's modeller, that would be GREAT! The reason I'm asking is that I'm in the process of trying to design something really low profile for a second floor apartment balcony for 75 and 80m. -- Dave Oldridge+ VA7CZ ICQ 1800667 Article: 219258 of rec.radio.amateur.antenna From: Jim - NN7K Subject: Re: Isotron antennas References: Message-ID: Date: Sat, 12 Nov 2005 20:31:46 GMT If you can get a copy of the November, 2005 "World Radio", check out "Kurt N Sturba"'s column, under "Aerials", on pg.55.-- he no dummy when coms to antennas, ect, and hides behind that nome d'plume to avoid conflicts with finger pointers. Tho on these antennas, a couple hundred words, but informative. In essence, he sez that these are very lossey, That a dipole (66 ft) on 40 meters would have a given bandwidth, IF the Isotron had the same effeciency for it's size, it would have a band- width of about 11 KHz. What it really has is a bandwidth of around 400 KHz this results in a signal about 2 "S" units , or 12 dB down from THAT reference dipole. In other words, there are better more effecient ways of radiating a signal! As information-- Jim NN7K Dave Oldridge wrote: > I've been seeing pictures of these weird antennas for years. Near as I can > tell from the picture, it's essentially a heavily-loaded very short dipole > with two large capacity hats at the ends. But it's impossible to tell from > the pictures what the exact configuration is. Can anyone tell me exactly > what's happening? Is the mast part of the radiating system? The feedline? > The literature (including the manuals) sort of implies that it is. > > Also, from the pictures, I get the impression that the standard mast-mount > configuration is mostly vertically polarized. This would certainly account > for reports I have read that the antenna is a bit of a dud at short range > on 80m. > > If someone has a computer model for it for MMHAMSOFT's modeller, that would > be GREAT! > > The reason I'm asking is that I'm in the process of trying to design > something really low profile for a second floor apartment balcony for 75 > and 80m. > Article: 219259 of rec.radio.amateur.antenna From: "John, N9JG" References: Subject: Re: Isotron antennas Message-ID: Date: Sat, 12 Nov 2005 20:58:09 GMT Gee, I'm sorry to hear that. I was hoping that you could get something for nothing. :-) -- John, N9JG "Jim - NN7K" wrote in message news:Sisdf.26121$6e1.21476@newssvr14.news.prodigy.com... > If you can get a copy of the November, 2005 "World Radio", check out > "Kurt N Sturba"'s column, under "Aerials", on pg.55.-- he no dummy > when coms to antennas, ect, and hides behind that nome d'plume to avoid > conflicts with finger pointers. Tho on these antennas, a couple hundred > words, but informative. In essence, he sez that these are very lossey, > That a dipole (66 ft) on 40 meters would have a given bandwidth, IF > the Isotron had the same effeciency for it's size, it would have a band- > width of about 11 KHz. What it really has is a bandwidth of around 400 > KHz this results in a signal about 2 "S" units , or 12 dB down from > THAT reference dipole. In other words, there are better more effecient > ways of radiating a signal! As information-- Jim NN7K > Article: 219260 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> Message-ID: Date: Sat, 12 Nov 2005 22:30:44 GMT Dave Platt wrote: > Does anybody have a copy of K1BQT's article from the Summer 1997 issue > of Communications Quarterly, on a method for constructing a 2-meter > extended double zepp antenna with a novel feed/matching arrangement? Is it better than just feeding it with about 15 inches of ladder-line? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219261 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Isotron antennas References: Message-ID: Date: Sat, 12 Nov 2005 22:38:13 GMT Dave Oldridge wrote: > The reason I'm asking is that I'm in the process of trying to design > something really low profile for a second floor apartment balcony for 75 > and 80m. A small one-turn loop is hard to beat. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219262 of rec.radio.amateur.antenna From: dplatt@radagast.org (Dave Platt) Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps Date: Sat, 12 Nov 2005 23:00:14 -0000 Message-ID: <11ncsvuf54l4v46@corp.supernews.com> References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> In article , Cecil Moore wrote: >> Does anybody have a copy of K1BQT's article from the Summer 1997 issue >> of Communications Quarterly, on a method for constructing a 2-meter >> extended double zepp antenna with a novel feed/matching arrangement? >Is it better than just feeding it with about 15 inches of ladder-line? Better? Dunno - maybe so, maybe no. The K1BQT design creates an EDZ using a pair of 38"-or-so rods or whips, and two just-under-10" lengths of RG-58 solid-core coax (conductor and braid shorted at the outer end, braid left open at the center where the antenna connects to the feedline). The lengths of RG-58 act as inductive stubs, cancelling out the capacitive reactance of the radiators; the lengths of the rods/whips are adjusted to yield a 50-ohm-per-side resistive impedancea at the feedpoint. The resulting 100-ohm impedance is matched to the feedline by a 3/4- wavelength piece of RG-59 75-ohm coax which is coiled around the center support... it serves both as an impedance transformer and a choke balun. If I were going to feed a 5/4 with ladder line, for tower side-mounting, I suppose I'd probably put the ladder line inside the PVC support arm, and then connect it to some 50-ohm coax which was wound around the outside of the arm to create a choke balun. -- 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: 219263 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> <11ncsvuf54l4v46@corp.supernews.com> Message-ID: Date: Sat, 12 Nov 2005 23:31:27 GMT Dave Platt wrote: > Cecil Moore wrote: >>Is it better than just feeding it with about 15 inches of ladder-line? > > If I were going to feed a 5/4 with ladder line, for tower > side-mounting, I suppose I'd probably put the ladder line inside the > PVC support arm, and then connect it to some 50-ohm coax which was > wound around the outside of the arm to create a choke balun. Cebik's stuff is probably for HF. EZNEC sez an 8 foot long, one inch diameter dipole at 36 ft. height has a feedpoint impedance of 86-j91 on 146 MHz. Heck, that's already better than some rubber duckies. All it takes to resonate that impedance to a 50 ohm SWR of about 1.6:1 is about 2.5 inches of 450 ohm ladder-line in series. What could possibly be simpler than that? -- 73, Cecil http://www.qsl.net/w5dxp Article: 219264 of rec.radio.amateur.antenna From: Jim - NN7K Subject: Re: Isotron antennas References: Message-ID: Date: Sat, 12 Nov 2005 23:46:49 GMT THAT was also quoted in the same article I stated. But would think a mobile antenna (this on second floor apt.), and a tripod mount, with radials for a counterpoise over a balcony (at night) would be much more effective than this dawg! think mfj or another outfit has the setup for this --- (maybe Outbacker, and that NOT that great)! Jim nn7k Cecil Moore wrote: > Dave Oldridge wrote: > >> The reason I'm asking is that I'm in the process of trying to design >> something really low profile for a second floor apartment balcony for >> 75 and 80m. > > > A small one-turn loop is hard to beat. Article: 219265 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Isotron antennas References: Message-ID: Date: Sun, 13 Nov 2005 00:17:44 GMT Jim - NN7K wrote: > THAT was also quoted in the same article I stated. But would think a > mobile antenna (this on second floor apt.), and a tripod mount, with > radials for a counterpoise over a balcony (at night) would be much more > effective than this dawg! Yes, more effective than the Isotron but disappointing, nevertheless (been there done that). A balcony-mounted mobile screwdriver is still pretty far down from a properly designed small loop on 75m. However, a vertical longer than a mobile screwdriver would be something worth considering. I think HighSierra has one of those. -- 73, Cecil http://www.qsl.net/w5dxp Article: 219266 of rec.radio.amateur.antenna From: nospam@nouce.bellatlantic.net Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps Message-ID: <4n3dn1t61erk7dlnbb9mtp8c7q70vor29q@4ax.com> References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> Date: Sun, 13 Nov 2005 00:54:09 GMT On Sat, 12 Nov 2005 22:30:44 GMT, Cecil Moore wrote: >Dave Platt wrote: >> Does anybody have a copy of K1BQT's article from the Summer 1997 issue >> of Communications Quarterly, on a method for constructing a 2-meter >> extended double zepp antenna with a novel feed/matching arrangement? > >Is it better than just feeding it with about 15 inches of ladder-line? No perfomance difference. Construction difference may favor one of the other. Allison Article: 219267 of rec.radio.amateur.antenna From: inagaddadavida@webtv.net (Jim) Subject: coax for 900mhz? Date: Sat, 12 Nov 2005 19:41:36 -0500 Message-ID: <11202-43768BC0-603@storefull-3258.bay.webtv.net> what coax is good to 900mhz? i am looking for something as thin and supple as i can find. i tried a hunk of coax off of an old cb antenna (wishful thinking) with no luck. should this work? or is hf coax no good at 900 mhz? i built a ten element yagi off a plan i found on the net. it should be a rocket ship but its not as good as a wide band rubber ducky that i have. i am trying to receive a 900mhz wireless microphone from a distance of about 200 yards. any ideas? Article: 219268 of rec.radio.amateur.antenna From: nospam@nouce.bellatlantic.net Subject: Re: Rick Littlefield K1BQT article on feeding extended double zepps Message-ID: References: <11n9b1ak6fquaaa@corp.supernews.com> <1131730430.536689.322880@g43g2000cwa.googlegroups.com> <11n9smon2j6q5d8@corp.supernews.com> <11ncsvuf54l4v46@corp.supernews.com> Date: Sun, 13 Nov 2005 00:57:47 GMT On Sat, 12 Nov 2005 23:31:27 GMT, Cecil Moore wrote: >Dave Platt wrote: > >> Cecil Moore wrote: >>>Is it better than just feeding it with about 15 inches of ladder-line? >> >> If I were going to feed a 5/4 with ladder line, for tower >> side-mounting, I suppose I'd probably put the ladder line inside the >> PVC support arm, and then connect it to some 50-ohm coax which was >> wound around the outside of the arm to create a choke balun. > >Cebik's stuff is probably for HF. EZNEC sez an 8 foot long, one >inch diameter dipole at 36 ft. height has a feedpoint impedance >of 86-j91 on 146 MHz. Heck, that's already better than some rubber >duckies. All it takes to resonate that impedance to a 50 ohm SWR >of about 1.6:1 is about 2.5 inches of 450 ohm ladder-line in >series. What could possibly be simpler than that? With EDZ or it's evil twin in the other plane the 5/8 wave the electrical length affects feed point R while the X is fairly large. So you use some form of matching magic to transform that unrulely X to R and thereby a match to a 50 ohm source and line. If you looked at the Cebik article you will see how and why plus it's result at 2m. I scaled his work for 6m and it worked to the the decimal point. Allison KB1GMX Article: 219269 of rec.radio.amateur.antenna Subject: Re: Isotron antennas From: Dave Oldridge References: Message-ID: Date: Sun, 13 Nov 2005 01:16:08 GMT Jim - NN7K wrote in news:J9vdf.11022 $BZ5.1804@newssvr13.news.prodigy.com: > THAT was also quoted in the same article I stated. But would think a > mobile antenna (this on second floor apt.), and a tripod mount, with > radials for a counterpoise over a balcony (at night) would be much more > effective than this dawg! think mfj or another outfit has the setup for > this --- (maybe Outbacker, and that NOT that great)! Jim nn7k Actually, I *am* thinking outbacker or MFJ. The balcony is large and aluminum-railed, which should actually form a decent counterpoise if it doesn't blast my sat. TV and 2m stuff all to heck. I just wondered what the theory is with the isotron. If it's actually exciting its mast (as some antennas do), then maybe I could use a similar technique to excite the balcony rail itself. A loop is not out of the question either, but to be at all efficient, it would have to be made of 1" or even 2" copper pipe. -- Dave Oldridge+ ICQ 1800667 Article: 219270 of rec.radio.amateur.antenna From: nospam@nouce.bellatlantic.net Subject: Re: coax for 900mhz? Message-ID: References: <11202-43768BC0-603@storefull-3258.bay.webtv.net> Date: Sun, 13 Nov 2005 01:51:21 GMT On Sat, 12 Nov 2005 19:41:36 -0500, inagaddadavida@webtv.net (Jim) wrote: >what coax is good to 900mhz? i am looking for something as thin and >supple as i can find. i tried a hunk of coax off of an old cb antenna >(wishful thinking) with no luck. should this work? or is hf coax no >good at 900 mhz? i built a ten element yagi off a plan i found on the >net. it should be a rocket ship but its not as good as a wide band >rubber ducky that i have. i am trying to receive a 900mhz wireless >microphone from a distance of about 200 yards. any ideas? Unless you go for exotica thin low loss coax at 900mhz is a contradiction in terms. RG58 at 900mhz is a dummy load after about 15ft. (20db/100ft) Belden 9914 is around 8db/100ft (.400inch size) RG8X is a low loss .242" cable thats only 12db/100 at 900mhz so if you use that and stay under 20ft the loss should be be under 3db still lossy but manageable. Generally if you want low loss cable at 900mhz you are talking about fat or very expensive cables. Allison KB1GMX Article: 219271 of rec.radio.amateur.antenna From: "John, N9JG" References: Subject: Re: Isotron antennas Message-ID: Date: Sun, 13 Nov 2005 02:05:32 GMT If you might consider a loop antenna, check out two electronic books, which are produced by antenneX Online Magazine. The two books are "The Loop Book" by Ted Hart, W5QJR, and "Small Magnetic Loops, Construction & Use" from antenneX. See http://www.antennex.com/Sshack/loopbk.htm http://www.antennex.com/Sshack/newloop.htm John, N9JG "Dave Oldridge" wrote in message news:Xns970CAFAA9E792doldridgsprintca@24.71.223.159... > Jim - NN7K wrote in news:J9vdf.11022 > $BZ5.1804@newssvr13.news.prodigy.com: > >> THAT was also quoted in the same article I stated. But would think a >> mobile antenna (this on second floor apt.), and a tripod mount, with >> radials for a counterpoise over a balcony (at night) would be much more >> effective than this dawg! think mfj or another outfit has the setup for >> this --- (maybe Outbacker, and that NOT that great)! Jim nn7k > > Actually, I *am* thinking outbacker or MFJ. The balcony is large and > aluminum-railed, which should actually form a decent counterpoise if it > doesn't blast my sat. TV and 2m stuff all to heck. > > I just wondered what the theory is with the isotron. If it's actually > exciting its mast (as some antennas do), then maybe I could use a similar > technique to excite the balcony rail itself. > > A loop is not out of the question either, but to be at all efficient, it > would have to be made of 1" or even 2" copper pipe. > > > -- > Dave Oldridge+ > ICQ 1800667 Article: 219272 of rec.radio.amateur.antenna From: "EasyRider" References: <11mvjfic11rdq9f@corp.supernews.com> Subject: Re: Loop Antennas Message-ID: Date: Sun, 13 Nov 2005 02:15:03 GMT Sound like your discribing my station setup. I also use a Delta loop in the shape of a diamond with the highest point at approximately 70 feet and the lowest opposite corner is about 40 feet, both above ground. Now it gets interesting as this set up is likely about 5 feet lower than the closest neighbouring amateur's basement floor is and I still out perform his inverted V. But the my loop is a full wave on 80 meters and I have a rather uneak piece of property. My soil is very good conductively and my ground happens to be a creek bed with a 8 inch water pipe submerged in the creek which runs all year round with about a foot of water over the pipe. Also when I was looking for property I drove my van in to the property as far as I could and call CQ on my mobile hf. Made a contact in Glasglow, Moscow and Japan. I bought the property that afternoon. And I haven't stopped enjoying the bands even when we are at the low side of a cycle. I've also played with a number of antennas and always came back to the delta loop or a four square. I'm planning on putting up a full wave delta loop for 160 meters this spring. My present loop is hooted up to a homebrew 4:1 balun with 300 ohm foam then a 10 foot piece of 9913 coax to a At-180 Icom tuner to a IC-706MKIIG. On a bad night I can make contacts about the Mississippe to Hawai, on a good night Europe and the Globe. If you have the room they are one of the best antennas for the money invested. But you still have to have a good location and a good ground, if your missing either there isn't an antenna in the world that will help you. By the way I'm 147 feet above sea level and my closest neighbouring amateur is 177 feet and his antenna is 30 feet above that, but I still out preform him hands down on any and all bands. Anyway this is what it's all about, haveing fun and making new friends. 73...de ve7agw, Al Vancovuer Island, BC "Michael" wrote in message news:11mvjfic11rdq9f@corp.supernews.com... >I get a lot of noise from my random wire antenna. It transmits very well >but is very noisy in receive. My neighbor put up a 280 foot loop antenna >which he feeds with ladder line. He feeds the ladder line from a 4 to 1 >balun to coax. The coax comes from a tuner. His setup performs very well on >all bands down to 75 meters. I went over to his shack last night and >listened to his receiver on 75. I was really impressed with the lack of >noise. I can safely say the difference in noise was profound. He has this >loop surrounding his house at a 30 ft. height. It is arranged in a square. > > Has anybody else had this experience with loops? It looks like I have room > to put up a triangular loop. Will this work as well? > > Can I use the same tuner I have now and just feed a coax into a balun. Or, > should I put the balun in the tuner and come straight out with ladder > line? There is a lot of room in this tuner. It is an old remote controlled > tuner surplused from a ship. > Article: 219273 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: coax for 900mhz? Message-ID: References: <11202-43768BC0-603@storefull-3258.bay.webtv.net> Date: Sun, 13 Nov 2005 02:17:08 GMT On Sat, 12 Nov 2005 19:41:36 -0500, inagaddadavida@webtv.net (Jim) wrote: >what coax is good to 900mhz? i am looking for something as thin and >supple as i can find. i tried a hunk of coax off of an old cb antenna >(wishful thinking) with no luck. should this work? or is hf coax no >good at 900 mhz? i built a ten element yagi off a plan i found on the >net. it should be a rocket ship but its not as good as a wide band >rubber ducky that i have. i am trying to receive a 900mhz wireless >microphone from a distance of about 200 yards. any ideas? LMR195 uses the same connectors as RG58, and has about 11dB loss / 100' at 900 MHz. You should find it stocked in the WLAN outlets, with or without connectors. Another thought is to salvage some foil/foam RG58 style cable from a car mobile phone antenna. Owen -- Article: 219274 of rec.radio.amateur.antenna From: "Caveat Lector" References: <11nd8rpkt9722e1@corp.supernews.com> Subject: Re: Stacking Distance Message-ID: <3Bydf.311$MN.203@fed1read07> Date: Sat, 12 Nov 2005 19:41:16 -0800 Rod - see ARRL advice -- URL: http://www.arrl.org/tis/info/HTML/stacking-yagis/ -- CL -- I doubt, therefore I might be ! "Rod Maupin" wrote in message news:11nd8rpkt9722e1@corp.supernews.com... > I'm putting up a VHF and UHF antenna and I am curious how apart they have > to be on the mast. I have no clue. Is there a rule of thumb? > > Thanks, > > Rod KI7CQ > > Article: 219275 of rec.radio.amateur.antenna From: "Rod Maupin" Subject: Re: Stacking Distance Date: Sat, 12 Nov 2005 20:30:32 -0800 Message-ID: <11ndgb9fm0vdne5@corp.supernews.com> References: <11nd8rpkt9722e1@corp.supernews.com> <3Bydf.311$MN.203@fed1read07> I checked out the article. Thanks. Rod Article: 219276 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Loop Antennas Date: Sat, 12 Nov 2005 23:55:41 -0500 Message-ID: <11ndhpe49afmb09@corp.supernews.com> References: <11mvjfic11rdq9f@corp.supernews.com> <11n47fl21h8li6e@corp.supernews.com> What I find amazing is that "Michael" leaves the impression that he is in ND when his neighbor W0BBM is in north central Kansas with two whole states in between. It gives a whole new meaning to "neighbor." Hard to compare antennas when the neighboring antennas are so far apart. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Michael" wrote in message news:11n47fl21h8li6e@corp.supernews.com... > I appreciate all the comments very much. A folded dipole would be easier for > me. I will discuss this with my neighbor W0BBN. He has been using a loop for > 20 years. It sounds like it is hard to go wrong if you are willing to put > out the work for a loop antenna. I have been away from low band work since > I started college. That has been very very long ago. I had never hear of a > loop antenna back in the 50s. There was no internet and other hams were few > and far between where I lived in the country. > > Article: 219277 of rec.radio.amateur.antenna From: BillJ Subject: Re: W9INN antenna Help References: <78ydnb1E5L2fxOveRVn-gg@comcast.com> Message-ID: Date: Sun, 13 Nov 2005 08:00:00 -0500 Steve wrote: > I have a Alpha Delta DX-A 40 80 and 160 antenna, feed point > is up 35 ft. I an comparing it to a W9INN 40 80 160 and it's only up > 28ft. > > My question is when running a ballun as the W9INN antenna does. > Can it be hung right to the tower leg or should it be on a stand off. > To keep it away from the tower legs buy 3 ft. > > The Alpha Delta DX-A wants to be hooked right to the tower leg. > > > There seems to be no difference between the both antennas > with the exception the W9INN antenna is set more to the middle of the > phone band for 40 80 and 160 were the Delta A is not . > > TNX for any input. > > Steve > > > > Are you saying the INN works better than the DX-A?