Article: 227513 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <44cae0f7$0$23676$5a62ac22@per-qv1-newsreader-01.iinet.net.au> <44cbc9ee$0$11790$c3e8da3@news.astraweb.com> Subject: Re: Harris RF-2601 auto remote ATU Message-ID: Date: Mon, 31 Jul 2006 20:59:41 -0700 "Hank Zoeller" wrote in message news:44cbc9ee$0$11790$c3e8da3@news.astraweb.com... > Bob VK4BYX wrote: Do you need to > > pressurise with nitrogen to achieve full specs of 1KW average power? > > Me? I use > nitrogen. I have used a company called Air Liquide. They have all kinds of gasses in all size tranks with gauges, hoses, fittings, etc. No preference for them ... it just worked that way. Article: 227514 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Reflection on Resistive loads Date: Tue, 01 Aug 2006 00:01:30 -0700 Message-ID: References: <1154385638.375433.178110@b28g2000cwb.googlegroups.com> <1154388135.791852.73530@s13g2000cwa.googlegroups.com> <12ct8f1str83m5a@corp.supernews.com> On Mon, 31 Jul 2006 19:35:45 -0500, "H. Adam Stevens, NQ5H" wrote: >That I knew in Jr High. > >Finally understood it when I studied E&M in college. You're miles ahead of me then. I'm tackling phonon dispersion right now. I know it, I should understand it (especially after weeks in the library), but there's always something in the corner of my mind on all sorts of these subjects that asks: "What the #%!@ ?" or as we said in tech school to conform to comm systems lingo: "What the #%!@ ? - Over." 73's Richard Clark, KB7QHC Article: 227515 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <2_OdnX7zdY6gVFzZRVny3w@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> Subject: Re: Radiating Efficiency Date: Tue, 1 Aug 2006 10:10:23 +0100 Message-ID: > 1.8 m -- Radial Z = 70.17 - j 24.1 > 1.9 m -- Radial Z = 68.5 - j 19.0 > 2.0 m -- Radial Z = 67.2 - j 14.2 > 2.1 m -- Radial Z = 66.2 - j 9.5 > 2.2 m -- Radial Z = 65.5 - j 5.0 > 2.3 m -- Radial Z = 65.1 - j 0.6 > 2.4 m -- Radial Z = 65.0 + j 3.6 > 2.5 m -- Radial Z = 65.2 + j 7.8 > 2.6 m -- Radial Z = 65.6 + j 11.7 > > I can keep going if you think that these are the results > you expected. I am tempted to continue, in steps of > 0.1 m, and plotting the results on the Smith Chart. > I expect the data to rapidly spiral to the center of > a chart normalized at 101. 6 ohms. > > Frank ====================================== Frank, Very interesting! I am plotting graphs of R and jX versus length of radial. Joining up the dots I expect to see shallow sinewaves superimposed on fairly level mean values. At present there is a definite shape of curve appearing in the reactance values while the resistance values are still fairly level. As length increases I expect to see something similar happening to the resistance curve which seems to be in between peaks and troughs. >From now on it seems safe for you to increase length in increments of 0.2 metres. There is no danger of missing peaks and troughs in the curves. Please keep up the good work. ---- Reg Article: 227516 of rec.radio.amateur.antenna Date: Tue, 1 Aug 2006 13:44:51 +0200 From: Dominique Michel Subject: Balun question and shielded loop Message-ID: <20060801134451.7b268bb0@localhost> I want to made a broadband receiving loop. It will be a one turn shielded loop of around 2 meters in diameter. The frequencies I want to be able to receive are the broadcasting band in Europa, LW (153 - 279 kHz), MW (531 - 1620 kHz) and SW (2310 - 25820 kHz). The antenna will have enough gain for the SW, but less gain on the 2 other bands. At the base will be a little box with the connection to the loop and a first balun 1:1 symmetrical to asymmetrical. The signal will just do a few centimeters to another box (a big one), and to an adjustable capacitor (a tuning cap from an old vacuum tube radio, so I can have a little motor to tune remotely the frequency of the loop). I plan to have a preamp, but only for LW and MW. It will have a higher maximum gain at low frequency, and this gain will be adjustable remotely with a voltage. Is it possible to do a such 1:1 balun with a bandwidth from 150 KHz to around 25 MHz and if yes, how? Another question is the size of the loop. I try a few coaxial cables to do the loop, and get a self resonance frequency of the loop between 8 to 11 MHz. So, the tuning cap work very well under this frequency, but its effect is hard to define above this frequency. If I decrease the size of the loop, I will get less signal, but the cap will work in a linear fashion on all the SW band. If I keep the same size, it work well, but the effect of the cap is hard to define above the self resonance frequency of the loop. And what about if I increase the size of the loop? Cheers, Dominique Article: 227517 of rec.radio.amateur.antenna From: "Reg Edwards" References: <44c93058$0$15863$4fafbaef@reader2.news.tin.it> Subject: Re: Seeking advice on balun Date: Tue, 1 Aug 2006 15:39:05 +0100 Message-ID: "Reg Edwards" wrote in message news:nfmdnQ63jaFnzlTZnZ2dnUVZ8s6dnZ2d@bt.com... > > "Antonio Vernucci" wrote > So, I decided to instead use an RF choke that quenches the common mode > RF. I firstly built a thick ferrite core by taping together five > 3/8"OD ferrite rods, 6-inch long. I then made 10 turns of a very thick > insulated red-black twin lead on it. The turns are widely spaced, so > as to have low capacitance between adjacent turns. > ========================================= > > Congratulations. You have just re-invented the choke balun. It's what > many people use. It is the best choice. Very often it is wound on a > ferrite ring. It has no impedance or turns ratio. > > Or it may consist of a number of ferrite sleeves which slide over the > transmission line. > > It is a mistake to use a balun between tuner and transmission line > which has a definite impedance or turns ratio. > ---- > Reg. > ====================================== A further comment - It may not be obvious, but a number of ferrite sleeves sliding over the transmissiom line, either coax line or twin line, corresponds to a single turn of line passing through an elongated ferrite ring. The formulae for calculating choking inductance, from dimensions and number of turns, is the same for one ferrite ring and a single or a number of sleeves. Obviously, there is more heavy, ferrite material used for sleeves because the number of turns is only one. But disregarding economics, a number of sleeves will eventually provide a better very-wide-band choke than a ferrite ring or a bundle of ferrite rods. Rich, intelligent, technical perfectionists, using high power, with plenty of spare time, are the most likely people to win contests. ---- Reg. Article: 227518 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Seeking advice on balun References: <44c93058$0$15863$4fafbaef@reader2.news.tin.it> Message-ID: Date: Tue, 01 Aug 2006 15:32:45 GMT Reg Edwards wrote: > Obviously, there is more heavy, ferrite material used for sleeves > because the number of turns is only one. But disregarding economics, a > number of sleeves will eventually provide a better very-wide-band > choke than a ferrite ring or a bundle of ferrite rods. Amidon specifies a typical Z for those toroidal coax sleeves. For instance, the Z is 215 ohms per core for FB-77-5621 cores at 25 MHz. My store-bought G5RV came with eight of those cores. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227519 of rec.radio.amateur.antenna Subject: Re: effect of metal pipe supporting a vertical cage antenna From: Dave Oldridge References: Message-ID: Date: Tue, 01 Aug 2006 17:26:02 GMT David George Johnson wrote in news:m5rrc29lnks7tadio21qp72aojh3mtmak1@4ax.com: > I want to put an eight wire vertical cage around a one hundred twenty > foot steel support for 80 meters. I can center feed the cage with > open wire line, which I assume will be more efficient than feeding the > steel at the bottom. The cage will not be in contact with the ground > or the tower. My thought is that the wires will make a better > radiator than the steel, but I have no idea what the steel "core" will > do to the efficiency of the antenna. I have had no success in > modelling this antenna. > > So my question is will the center fed, ungrounded cage dipole provide > any real advantage over feeding the tower at the bottom? You know what I think would work better? Four slopers running off at different angles, 45 degrees from the top of that 120 foot mast. You could even tune the unused slopers for a better pattern. Even three slopers would do it, I think. -- Dave Oldridge+ ICQ 1800667 Article: 227520 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Balun question and shielded loop Date: Tue, 01 Aug 2006 10:31:24 -0700 Message-ID: <12cv3vfi3sqhgfd@corp.supernews.com> References: <20060801134451.7b268bb0@localhost> In order to be effective, a balun's common mode impedance has to be at least several times greater than the common mode impedance of the antenna. The common mode impedance of a very small loop like that will be very high, so it won't be possible to make an effective balun, except perhaps at the high end of your frequency range. I suggest that you use a "shielded" loop. This is a technique to improve the balance. Also take as much care as you can to keep the loop physically symmetrical. A frequency range of more than 150:1 seems ambitious to me, but I'll defer to folks who have more experience with loops than I do. Roy Lewallen, W7EL Dominique Michel wrote: > I want to made a broadband receiving loop. It will be a one turn > shielded loop of around 2 meters in diameter. The frequencies I want to > be able to receive are the broadcasting band in Europa, LW (153 - 279 > kHz), MW (531 - 1620 kHz) and SW (2310 - 25820 kHz). The antenna will have enough gain for the > SW, but less gain on the 2 other bands. > > At the base will be a little box with the connection to the loop and a first balun 1:1 symmetrical to asymmetrical. The signal will just do a few centimeters to another box (a big one), and to an adjustable capacitor (a tuning cap from an old vacuum tube radio, so I can have a little motor to tune remotely the frequency of the loop). > > I plan to have a preamp, but only for LW and MW. It will have a higher maximum gain at low frequency, and this gain will be adjustable remotely with a voltage. > > Is it possible to do a such 1:1 balun with a bandwidth from 150 KHz to around 25 MHz and if yes, how? > > Another question is the size of the loop. I try a few coaxial cables to do the loop, and get a self resonance frequency of the loop between 8 to 11 MHz. So, the tuning cap work very well under this frequency, but its effect is hard to define above this frequency. If I decrease the size of the loop, I will get less signal, but the cap will work in a linear fashion on all the SW band. If I keep the same size, it work well, but the effect of the cap is hard to define above the self resonance frequency of the loop. And what about if I increase the size of the loop? > > > Cheers, > Dominique Article: 227521 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: neighborhood antenna restrictions Date: Tue, 01 Aug 2006 16:20:27 -0400 Message-ID: References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> Bob Agnew wrote: >> If current Laws we enforced, half the population would be behind bars, >> and the other half would be guarding them........... >> > > The way my HOA enforces it is to levy a $200 fine in the form of a Mortgage > impound on the first violation, with an increasing fine every two weeks > thereafter. Why on earth would anyone live in one of those places? And yes there are alternatives. I live in a development that doesn't have that that kind of insane meddling going on. I can have a tower even, as long as it has enough room to fall down within my yard and not hit the neighbors. - 73 de Mike KB3EIA - Article: 227522 of rec.radio.amateur.antenna From: jgboyles@aol.com Subject: Re: Reflection on Resistive loads Date: 1 Aug 2006 13:49:31 -0700 Message-ID: <1154465371.724824.311470@m73g2000cwd.googlegroups.com> References: <1154057457.019523.86470@p79g2000cwp.googlegroups.com> Bob Agnew wrote: > > Hi Bob, I have never taught at the University level myself, this is an > > "Amateur" newsgroup. If you look at the Smith Chart, 1/2WL reflects > > OK __ I won't post here anymore. I once was an Amateur when I was 14. > I thought that I wanted to get back into the hobby now that I am retired. Hi Bob, I'm sorry if you read something into my "amateur" statement that I did not mean. I for one would welcome you to post on anything, anytime you wish. I would also like to welcome you back into the hobby, if that what you would like to do. I became a Ham when I was about 14. Am an EE, but never worked in the RF end of things. When I post on the antenna group, I am an Amateur. 73 Gary N4AST Article: 227523 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: effect of metal pipe supporting a vertical cage antenna Date: Tue, 01 Aug 2006 14:18:04 -0700 Message-ID: References: On Tue, 01 Aug 2006 17:26:02 GMT, Dave Oldridge wrote: >You know what I think would work better? Four slopers running off at >different angles, 45 degrees from the top of that 120 foot mast. You could >even tune the unused slopers for a better pattern. > >Even three slopers would do it, I think. Hi Dave, Great advice that maximizes what he has. 73's Richard Clark, KB7QHC Article: 227524 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Tue, 01 Aug 2006 14:35:03 -0700 Message-ID: <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> ORIGINAL MESSAGE: On Tue, 01 Aug 2006 16:20:27 -0400, Michael Coslo wrote: > Why on earth would anyone live in one of those places? And yes there >are alternatives. I live in a development that doesn't have that that >kind of insane meddling going on. I can have a tower even, as long as it >has enough room to fall down within my yard and not hit the neighbors. ------------ REPLY SEPARATOR ------------ Couldn't agree more. Move away from the Fascist Homeowners Association and get in an area where people know enough to leave each other alone! Your blood pressure will go down, your enjoyment of life will go up and you might live long enough to Work All Stations. Ok, a tad exaggerated but you get the idea. 73, BIll W6WRT Article: 227525 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: neighborhood antenna restrictions Date: Tue, 01 Aug 2006 15:33:20 -0700 Message-ID: References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Bill Turner wrote: > Move away from the Fascist Homeowners Association > and get in an area where people know enough to leave each other alone! Isn't the elimination of the rights of property owners more of a Socialist ideal? That characterization would be a bit more consistent with the "climate" here in this state. 73, ac6xg Article: 227526 of rec.radio.amateur.antenna From: "Kris, KC7VWQ" Subject: indoor listening antenna Date: 1 Aug 2006 15:46:20 -0700 Message-ID: <1154472380.495339.322680@75g2000cwc.googlegroups.com> My apartment complex recently restricted me to having only antennas on the inside, and I was wondering what would work best for listening to the HF and shortwave bands. I live on the first floor, with no access to an attic. Kris KC7VWQ Article: 227527 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: neighborhood antenna restrictions References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Message-ID: Date: Tue, 01 Aug 2006 22:54:42 GMT Jim Kelley wrote: > Isn't the elimination of the rights of property owners more of a > Socialist ideal? National Socialists? -- 73, Cecil http://www.qsl.net/w5dxp Article: 227528 of rec.radio.amateur.antenna Message-ID: <44CFDCCA.4070309@fuse.net> Date: Tue, 01 Aug 2006 18:59:22 -0400 From: jawod Subject: Re: neighborhood antenna restrictions References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> Michael Coslo wrote: > Bob Agnew wrote: > >>> If current Laws we enforced, half the population would be behind bars, >>> and the other half would be guarding them........... If you're Black, we're just about there now. Article: 227529 of rec.radio.amateur.antenna Message-ID: <44CFDE64.4050804@fuse.net> Date: Tue, 01 Aug 2006 19:06:12 -0400 From: jawod Subject: Re: neighborhood antenna restrictions References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> > > > Isn't the elimination of the rights of property owners more of a > Socialist ideal? No, it's definitely fascist, bundle of sticks and all that. Uniformity at all costs. Oddly, at their extremes, fascism and socialism sort of meet. Barney Fife is a fascist, Barney Miller is a socialist. Barney the purple Dinosaur is politically unaffiliated. Article: 227530 of rec.radio.amateur.antenna From: "Tam/WB2TT" References: <1154472380.495339.322680@75g2000cwc.googlegroups.com> Subject: Re: indoor listening antenna Date: Tue, 1 Aug 2006 20:10:12 -0400 Message-ID: "Kris, KC7VWQ" wrote in message news:1154472380.495339.322680@75g2000cwc.googlegroups.com... > My apartment complex recently restricted me to having only antennas on > the inside, and I was wondering what would work best for listening to > the HF and shortwave bands. I live on the first floor, with no access > to an attic. > > Kris > KC7VWQ > These people are usually too dumb to associate a wire with an antenna. Try jamming a length of #30 wire out the top of a window, and throw the other end as far up a tree as you can. Tam/WB2TT Article: 227531 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> Subject: Re: Radiating Efficiency Date: Wed, 2 Aug 2006 01:15:43 +0100 Message-ID: Frank, I don't understand Smith Charts. But you can tell me what conclusions the charts lead you to believe about the behaviour of a lossy transmission line of various lengths. I am concerned with reducing the uncertainty of my program from the information contained in the graphs of input impedance versus length which I am now able to complete. I don't suppose you would like to repeat the excercise using a ground resistivity of 1000 ohm-metres. Or repeating at 20 MHz. ---- Reg. "Frank's" wrote in message news:1qOzg.181008$771.118115@edtnps89... > > "Frank's" wrote in message > news:H6Mzg.180983$771.142858@edtnps89... > > > > "Reg Edwards" wrote in message > > news:lcGdnVfIUMnxhlLZRVnytg@bt.com... > >>> 1.8 m -- Radial Z = 70.17 - j 24.1 > >>> 1.9 m -- Radial Z = 68.5 - j 19.0 > >>> 2.0 m -- Radial Z = 67.2 - j 14.2 > >>> 2.1 m -- Radial Z = 66.2 - j 9.5 > >>> 2.2 m -- Radial Z = 65.5 - j 5.0 > >>> 2.3 m -- Radial Z = 65.1 - j 0.6 > >>> 2.4 m -- Radial Z = 65.0 + j 3.6 > >>> 2.5 m -- Radial Z = 65.2 + j 7.8 > >>> 2.6 m -- Radial Z = 65.6 + j 11.7 > >>> > >>> I can keep going if you think that these are the results > >>> you expected. I am tempted to continue, in steps of > >>> 0.1 m, and plotting the results on the Smith Chart. > >>> I expect the data to rapidly spiral to the center of > >>> a chart normalized at 101. 6 ohms. > >>> > >>> Frank > >> ====================================== > >> Frank, > >> > >> Very interesting! > >> > >> I am plotting graphs of R and jX versus length of radial. > >> > >> Joining up the dots I expect to see shallow sinewaves superimposed on > >> fairly level mean values. > >> > >> At present there is a definite shape of curve appearing in the > >> reactance values while the resistance values are still fairly level. > >> > >> As length increases I expect to see something similar happening to the > >> resistance curve which seems to be in between peaks and troughs. > >> > >> From now on it seems safe for you to increase length in increments of > >> 0.2 metres. There is no danger of missing peaks and troughs in the > >> curves. > >> > >> Please keep up the good work. > >> ---- > >> Reg > > > > 1.8 m -- Radial Z = , I have reached 7.4m, but there does not seem > > any point in continuing. Let me know what you think. It does not > > appear to be behaving as I would expect of a transmission line; > > but then I have no experience of transmission lines immersed > > in a lossy material. > > > > Also note the jump in impedance at 5.6 m. I double checked the > > result, and it appears to be correct. > > > > 2.8 m -- Radial Z = 67.5 + j 19.2 > > 3.0 m -- Radial Z = 70.6 + j 25.9 > > 3.2 m -- Radial Z = 74.7 + j 31.6 > > 3.4 m -- Radial Z = 79.8 + j 36.0 > > 3.6 m -- Radial Z = 85.5 + j 39.0 > > 3.8 m -- Radial Z = 91.4 + j 40.4 > > 4.0 m -- Radial Z = 97.1 + j 40.2 > > 4.2 m -- Radial Z = 102.0 + j 38.6 > > 4.4 m -- Radial Z = 105.9 + j 35.9 > > 4.6 m -- Radial Z = 108.6 + j 32.7 > > 4.8 m -- Radial Z = 110.1 + j 29.3 > > 5.0 m -- Radial Z = 110.5 + j 26.1 > > 5.2 m -- Radial Z = 110.1 + j 23.3 > > 5.4 m -- Radial Z = 109.2 + j 17.2 > > 5.6 m -- Radial Z = 107.9 + j 19.5 > > 5.8 m -- Radial Z = 106.5 + j 18.4 > > 6.0 m -- Radial Z = 105.1 + j 17.7 > > 6.2 m -- Radial Z = 103.8 + j 17.5 > > 6.4 m -- Radial Z = 102.7 + j 17.6 > > 6.6 m -- Radial Z = 101.7 + j 17.9 > > 6.8 m -- Radial Z = 101.0 + j 18.4 > > 7.0 m -- Radial Z = 100.5 + j 19.0 > > 7.2 m -- Radial Z = 100.2 + j 19.6 > > 7.4 m -- Radial Z = 100.1 + j 20.2 > > . > > . > > 8.0 m -- Radial Z = 100.5 + j 21.4 > > . > > . > > 9.0 m -- Radial Z = 101.8 + j 21.7 > > > > These data are so close to the center of a Smith Chart > > normalized to 101.6 + j 21. Not sure how you > > normalize with a complex number, but assume it is > > with the magnitude of Z. > > Reg: > > It seems that the Smith Chart must be normalized with a > complex number. As expected, with a very high loss > transmission line, the impedance rapidly spirals towards > the complex Zo. From the data it is not clear what is > really happening, but on the Smith Chart it becomes > very clear. The curve crosses the "Real" axis at: 2.8 m, > 5.8 m, and about 9 m. At this point the data are so > close to the Smith Chart center that any more > results are irrelevant. Even without a Smith Chart, > normalization of the data will clearly reveal where the > quarter wave multiples are located. > > Frank > > Article: 227532 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Tue, 01 Aug 2006 17:33:44 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> ORIGINAL MESSAGE: On Tue, 01 Aug 2006 15:33:20 -0700, Jim Kelley wrote: >Isn't the elimination of the rights of property owners more of a >Socialist ideal? ------------ REPLY SEPARATOR ------------ Maybe. Socialism has to do with ownership, fascism has to do with control. Obviously there can be some overlap. A quote from dictionary.com: "Fascism: A system of government marked by centralization of authority under a dictator, stringent socioeconomic controls, suppression of the opposition through terror and censorship, and typically a policy of belligerent nationalism and racism." Sounds like a Homeowners Association to me. :-) Bill, W6WRT Article: 227533 of rec.radio.amateur.antenna From: "Yuri Blanarovich" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> Subject: Re: Radiating Efficiency Message-ID: Date: Tue, 1 Aug 2006 21:40:18 -0400 "Reg Edwards" wrote > > But you can tell me what conclusions the charts lead you to believe > about the behaviour of a lossy transmission line of various lengths. > Sooo, are we investigating behaviour of lossy transmission lines heating the worms, aka wire in a dirt, or behaviour of radial within the vertical antenna, aka the other half of a "dipole" and it's participation in forming the radiation pattern and effciency? Helooooo?!? What's next? Shortening the radiator? As a test case, see how "inefficient" is the 3/8 wave vertical, with 360 3/8 wave radials on 160m. If your "software" tels me that it will be more efficient with 1 m radials, you are in for serious reality check. Yuri, K3BU Article: 227534 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: neighborhood antenna restrictions Date: Tue, 01 Aug 2006 18:45:06 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> On Tue, 01 Aug 2006 17:33:44 -0700, Bill Turner wrote: >"Fascism: > >A system of government marked by centralization of authority under a >dictator, stringent socioeconomic controls, suppression of the >opposition through terror and censorship, and typically a policy of >belligerent nationalism and racism." > >Sounds like a Homeowners Association to me. :-) Hi Bill, Do they subscribe to "signing statements?" 73's Richard Clark, KB7QHC Article: 227535 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Tue, 01 Aug 2006 20:08:43 -0700 Message-ID: <2p50d25p1lrk4qci7eog2lnu7evkhj3f3g@4ax.com> References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> ORIGINAL MESSAGE: On Tue, 01 Aug 2006 18:45:06 -0700, Richard Clark wrote: >Hi Bill, > >Do they subscribe to "signing statements?" > >73's >Richard Clark, KB7QHC ------------ REPLY SEPARATOR ------------ Who is "they" and what is a "signing statement"? Bill, W6WRT Article: 227536 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: neighborhood antenna restrictions Date: Tue, 01 Aug 2006 20:40:39 -0700 Message-ID: <6370d21pvqocqs2t9p4a3am0mg5ee71tl7@4ax.com> References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <2p50d25p1lrk4qci7eog2lnu7evkhj3f3g@4ax.com> On Tue, 01 Aug 2006 20:08:43 -0700, Bill Turner wrote: >ORIGINAL MESSAGE: > >On Tue, 01 Aug 2006 18:45:06 -0700, Richard Clark > wrote: > >>Hi Bill, >> >>Do they subscribe to "signing statements?" >> >>73's >>Richard Clark, KB7QHC > >------------ REPLY SEPARATOR ------------ > >Who is "they" and what is a "signing statement"? Hi Bill, They: the Homeowners Association signing statement: a Fascist rewriting of a contract already entered into. I can anticipate a "no" in response to my question, and as such the Homeowners Association ceases to qualify for the current state of the Fascist art. 73's Richard Clark, KB7QHC Article: 227537 of rec.radio.amateur.antenna From: nm5k@wt.net Subject: Re: Balun question and shielded loop Date: 2 Aug 2006 02:27:33 -0700 Message-ID: <1154510853.330684.133750@p79g2000cwp.googlegroups.com> References: <20060801134451.7b268bb0@localhost> Dominique Michel wrote: > I want to made a broadband receiving loop. It will be a one turn > shielded loop of around 2 meters in diameter. The frequencies I want to > be able to receive are the broadcasting band in Europa, LW (153 - 279 > kHz), MW (531 - 1620 kHz) and SW (2310 - 25820 kHz). The antenna will have enough gain for the > SW, but less gain on the 2 other bands. I agree with Roy... Pretty ambitious range you want... I'd concentrate on the LW, and hope for the best as a "random" antenna for the upper HF ranges.. There is really no such thing as a "broadband" small loop, unless you do some drastic designing. On those lower frequencies the tuning will be very sharp. You will want to retune the cap for most any large frequency change. Being the self resonant frequency of a true LW loop using practical value variables is going to be low, there is not much point in trying to use it for higher frequencies unless you can live with it as a random antenna. I'd have a 2nd loop for the higher bands. Also one turn 2m dia? Good luck on LW... You are going to need some high pf cap values.. It would probably be more practical to use a multi turn loop if you want to use the average BC variable. Depends on the cap. The average dual gang variable for old AM radios were usually about 365pf x 2 for a total of 730 pf. Some caps in old AM/FM receivers have more gangs, and a bit higher total.. I've got a diamond loop next to me that is 44 inches per side. It has 5 turns. With the variable cap I have, my low end is 500 kc. To tune LW, I must add on extra fixed caps. Using all the gangs, my upper limit on MW is about 1300 kc?? or so. I forgot exactly, but I think it's below the upper end of the MW band. I have to switch to a single small gang to tune higher frequencies. My upper limit is about 2300 kc or so... And thats with a very small cap value.. Sure, I can listen on HF, but it will never be properly tuned. A small loop is not that great an antenna for the HF bands anyway.. You would probably be better off to string out a wire.. BTW, I don't use a balun or a preamp on mine. I realize that the unbalanced to balanced connection is not the greatest thing, but in the real world, it's pretty much a non issue once the antenna is tuned. I notice very little skewing of the pattern, and have had no noise issues. Using a shielded loop, or shielded coupling loop can help balance if it ends up being a problem, but in comparing both shielded and non shielded coupling loops, I saw very little difference. My antenna is well balanced and symmetrical, so that probably helps. I've never needed the preamp.. Plenty of signal as is. Will vary to the radio. If you tune the loop so it actually will tune HF, you won't be able to properly tune it for LW using a BC variable cap. And LW and MW is where you really want the loop. You can use anything for HF... Reg has a pretty decent program for "what iffing" small loops.. "rjeloop3" You might check it out. You will be able to see your appx ranges using the caps you have, number of turns, etc.. I've compared it with real loops and it's close nuff fer gov work. MK Article: 227538 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> Subject: Re: Radiating Efficiency Date: Wed, 2 Aug 2006 10:30:57 +0100 Message-ID: Frank, To complete the graphs of Rin + jXin versus length for one radial, I need data for lengths between 0.5 metres and 2 metres at intervals of 0.2 metres. Could you oblige please? The nice smooth graphs I have produced so far are free of 'measurement' errors which could be attributed to your hard, tedious work. The uncertainty due to NEC4 is as yet unknown. In the NEC4 model of a single radial, what is the length of the short bits of radial used to model it? Alternatively, into what number of short lengths is the radial under test divided? ---- Reg, G4FGQ. Article: 227539 of rec.radio.amateur.antenna Date: Wed, 2 Aug 2006 12:39:08 +0200 From: Dominique Michel Subject: Re: Balun question and shielded loop Message-ID: <20060802123908.6b0df71c@localhost> References: <20060801134451.7b268bb0@localhost> Le 2 Aug 2006 02:27:33 -0700, nm5k@wt.net a écrit : > > Dominique Michel wrote: > > I want to made a broadband receiving loop. It will be a one turn > > shielded loop of around 2 meters in diameter. The frequencies I want to > > be able to receive are the broadcasting band in Europa, LW (153 - 279 > > kHz), MW (531 - 1620 kHz) and SW (2310 - 25820 kHz). The antenna will have enough gain for the > > SW, but less gain on the 2 other bands. > > I agree with Roy... Pretty ambitious range you want... I'd concentrate > on the LW, and hope for the best as a "random" antenna for the upper > HF ranges.. There is really no such thing as a "broadband" small loop, > unless you do some drastic designing. On those lower frequencies > the tuning will be very sharp. You will want to retune the cap for > most any large frequency change. Being the self resonant frequency > of a true LW loop using practical value variables is going to be low, > there is not much point in trying to use it for higher frequencies > unless I was thinking to use an additional balun between the cap and the antenna for the MW band and another one for the LW band, so at the antenna see a capacitance value multiplied by the power of the rate of the balun. > you can live with it as a random antenna. I'd have a 2nd loop for the > higher bands. Also one turn 2m dia? Good luck on LW... You are going to > need some high pf cap values.. It would probably be more practical to > use a multi turn loop if you want to use the average BC variable. > Depends on the cap. The average dual gang variable for old AM radios > were usually about 365pf x 2 for a total of 730 pf. Some caps in old > AM/FM receivers have more gangs, and a bit higher total.. It is such a cap I have. > I've got a diamond loop next to me that is 44 inches per side. It has > 5 turns. With the variable cap I have, my low end is 500 kc. To tune > LW, > I must add on extra fixed caps. Using all the gangs, my upper limit on > MW is about 1300 kc?? or so. I forgot exactly, but I think it's below > the > upper end of the MW band. I have to switch to a single small gang to > tune higher frequencies. My upper limit is about 2300 kc or so... And > thats with a very small cap value.. Sure, I can listen on HF, but it > will > never be properly tuned. A small loop is not that great an antenna for > the HF bands anyway.. You would probably be better off to string out a > wire.. I am living in a city in Switzerland, and a long wire is not an option. > BTW, I don't use a balun or a preamp on mine. I realize that the > unbalanced > to balanced connection is not the greatest thing, but in the real > world, > it's pretty much a non issue once the antenna is tuned. I notice very > little skewing of the pattern, and have had no noise issues. Using a > shielded loop, or shielded coupling loop can help balance if it ends up > being a problem, but in comparing both shielded and non shielded > coupling loops, I saw very little difference. My antenna is well > balanced > and symmetrical, so that probably helps. > I've never needed the preamp.. Plenty of signal as is. Will vary to the > radio. > If you tune the loop so it actually will tune HF, you won't be able to > > properly tune it for LW using a BC variable cap. And LW and MW is > where you really want the loop. You can use anything for HF... 2 loops or one loop and a vertical antenna can be an option, one for LW and MW, the second one for SW. I just received the balanis, and it have an extended chapter on the loop. I have just begun to read it. It appear at, with a big loop as my 2 meters diameter on SW, the resistance as the reactance of the loop show a very big and very sharp increase when the circumference of the loop is between 0.4 and 0.6 wavelength. So, in fact, a bigger loop as a 2 meters diameter will be needed, but I cannot use a coaxial cable if I want to be able to tune it (too much parasitic cap). So maybe at a vertical will be better because I don't know if I can manage a so big loop where I am living. > Reg has a pretty decent program for "what iffing" small loops.. > "rjeloop3" > You might check it out. You will be able to see your appx ranges using > the > caps you have, number of turns, etc.. I've compared it with real loops > and > it's close nuff fer gov work. > MK > I will check this program. Thank you. Dominique Article: 227540 of rec.radio.amateur.antenna Date: Wed, 2 Aug 2006 12:43:31 +0200 From: Dominique Michel Subject: Re: Balun question and shielded loop Message-ID: <20060802124331.7a9d89f5@localhost> References: <20060801134451.7b268bb0@localhost> Thank you. If I want to model a such shielded loop for spice, do you know if it is just to model a normal loop and add the capacity between the core and the shield? > In order to be effective, a balun's common mode impedance has to be at > least several times greater than the common mode impedance of the > antenna. The common mode impedance of a very small loop like that will > be very high, so it won't be possible to make an effective balun, except > perhaps at the high end of your frequency range. > > I suggest that you use a "shielded" loop. This is a technique to improve > the balance. Also take as much care as you can to keep the loop > physically symmetrical. 2 loops can be an option, or a loop for the LW and MW bands and a vertical for the SW band. Bset, Dominique > > A frequency range of more than 150:1 seems ambitious to me, but I'll > defer to folks who have more experience with loops than I do. > > Roy Lewallen, W7EL > > Dominique Michel wrote: > > I want to made a broadband receiving loop. It will be a one turn > > shielded loop of around 2 meters in diameter. The frequencies I want to > > be able to receive are the broadcasting band in Europa, LW (153 - 279 > > kHz), MW (531 - 1620 kHz) and SW (2310 - 25820 kHz). The antenna will have enough gain for the > > SW, but less gain on the 2 other bands. > > > > At the base will be a little box with the connection to the loop and a first balun 1:1 symmetrical to asymmetrical. The signal will just do a few centimeters to another box (a big one), and to an adjustable capacitor (a tuning cap from an old vacuum tube radio, so I can have a little motor to tune remotely the frequency of the loop). > > > > I plan to have a preamp, but only for LW and MW. It will have a higher maximum gain at low frequency, and this gain will be adjustable remotely with a voltage. > > > > Is it possible to do a such 1:1 balun with a bandwidth from 150 KHz to around 25 MHz and if yes, how? > > > > Another question is the size of the loop. I try a few coaxial cables to do the loop, and get a self resonance frequency of the loop between 8 to 11 MHz. So, the tuning cap work very well under this frequency, but its effect is hard to define above this frequency. If I decrease the size of the loop, I will get less signal, but the cap will work in a linear fashion on all the SW band. If I keep the same size, it work well, but the effect of the cap is hard to define above the self resonance frequency of the loop. And what about if I increase the size of the loop? > > > > > > Cheers, > > Dominique Article: 227541 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: neighborhood antenna restrictions Date: Wed, 02 Aug 2006 08:54:45 -0400 Message-ID: References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Jim Kelley wrote: > > > Bill Turner wrote: > > >> Move away from the Fascist Homeowners Association >> and get in an area where people know enough to leave each other alone! > > Isn't the elimination of the rights of property owners more of a > Socialist ideal? That characterization would be a bit more consistent > with the "climate" here in this state. You would think, wouldn't ya? Yet I find both far left and far right to be equally meddlesome. Just different tactics. - Mike - Article: 227542 of rec.radio.amateur.antenna From: "Harbin Osteen" Subject: Any info on this type of mobile antenna? Date: Wed, 2 Aug 2006 06:03:09 -0700 Message-ID: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> Any info on this type of mobile antenna?: http://www.gordon.army.mil/AC/Winter/Winter%2001/images/gerc2veh.jpg -- SeeYaa:) Harbin Osteen KG6URO !sdohtem noitpyrcne devorppa-tnemnrevog troppus I - Article: 227543 of rec.radio.amateur.antenna From: Paul Hinman Subject: VENT Re: (OT) : Democrat's Out-Sourcing "Hate America" To Canada References: <129m9ijcnshm47f@corp.supernews.com> <129ofcclvejs22f@corp.supernews.com> <0bjo92p0h2dfqcum243lc3u1mqv49nu10h@4ax.com> <1152720850.662591.37690@b28g2000cwb.googlegroups.com> <1152839909.231750.229790@35g2000cwc.googlegroups.com> <1152848674.361536.176700@h48g2000cwc.googlegroups.com> Message-ID: Date: Wed, 02 Aug 2006 13:42:11 GMT This is a multi-part message in MIME format. --------------010605080904080802080806 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit J. D. B. wrote: > Well at least your estate will get to keep your life savings. If you > get sick late in the year, and the healthcare facility/hospital shut > down for the rest of the year because it ran out of government money > (a typical scenario in Canada), there will be no one to give you any > care and you'll just die. But hey, your life savings will still be > intact! Is socialized health care great or what? > >> >> - At least in Canada you get to keep >> - your life savings if you get sick. >> I am a Canadian with serious chronic health problems and I have much more experience with the health system than I would like to have, I have come close being a silent key several times, I am sure that there are some who feel that is too bad that I was allowed to breed before my medical problems became obvious. In the minds of some I suppose that I have peed in the genetic pool. I have never heard of a Canadian hospital shutting down because the money did not last until fiscal year end. While there are some weaknesses in our system such as delays in elective procedures but when the sand was running out of the hour glass there was always a system to help me out. Here everyone can get insured, there is an option to opt out of medicare but who would? Think of the overhead that American doctors face having to deal with multiple insurance companies, each with different forms and procedures. Think of the people who can't get medical insurance no matter what the cost. Think of those who don't have because they can't afford it. And then there are those who exercise their right not have it. In a situation where people get treated but can't afford to pay, the rates for everyone else must go up to compensate. Canada is not perfect but it is a pretty nice place to live and we try to contribute as best we can. By the way, if I were an American I would vote republican but I am not a single issue voter so don't construe that to mean that I from the far right wing. Consider me a fiscal conservative with a social conscience. -- Paul S. Hinman - VE6LDS long West 113 deg 27 min 20 sec lat North 53 deg 27 min 3 sec Maidenhead Locator DO33gk --------------010605080904080802080806 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit J. D. B. wrote:
Well at least your estate will get to keep your life savings. If you get sick late in the year, and the healthcare facility/hospital shut down for the rest of the year because it ran out of government money (a typical scenario in Canada), there will be no one to give you any care and you'll just die.  But hey, your life savings will still be intact! Is socialized health care great or what?

- At least in Canada you get to keep
- your life savings if you get sick.

I am a Canadian with serious chronic health problems and I have much more experience with the health system than I would like to have,  I have come close being a silent key several times, I am sure that there are some who feel that is too bad that I was allowed to breed before my medical problems became obvious.  In the minds of some I suppose that I have peed in the genetic pool. 

I have never heard of a Canadian hospital shutting down because the money did not last until fiscal year end.  While there are some weaknesses in our system such as delays in elective procedures but when the sand was running out of the hour glass there was always a system to help me out.  Here everyone can get insured, there is an option to opt out of medicare but who would?

Think of the overhead that American doctors face having to deal with multiple insurance companies, each with different forms and procedures.  Think of the people who can't get medical insurance no matter what the cost.  Think of those who don't have because they can't afford it.  And then there are those who exercise their right not have it.

In a situation where people get treated but can't afford to pay, the rates for everyone else must go up to compensate.

Canada is not perfect but it is a pretty nice place to live and we try to contribute as best we can.

By the way, if I were an American I would vote republican but I am not a single issue voter so don't construe that to mean that I from the far right wing.  Consider me a fiscal conservative with a social conscience.

-- 
Paul S. Hinman - VE6LDS
long West 113 deg 27 min 20 sec
lat  North 53 deg 27 min 3 sec
Maidenhead Locator DO33gk 

--------------010605080904080802080806-- Article: 227544 of rec.radio.amateur.antenna From: "Frank's" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> Subject: Re: Radiating Efficiency Message-ID: <8h2Ag.182604$S61.120179@edtnps90> Date: Wed, 02 Aug 2006 14:03:48 GMT "Reg Edwards" wrote in message news:ILadnRpPz7mT7E3ZRVnyiQ@bt.com... > Frank, > > To complete the graphs of Rin + jXin versus length for one radial, I > need data for lengths between 0.5 metres and 2 metres at intervals of > 0.2 metres. > > Could you oblige please? > > The nice smooth graphs I have produced so far are free of > 'measurement' errors which could be attributed to your hard, tedious > work. > > The uncertainty due to NEC4 is as yet unknown. In the NEC4 model of a > single radial, what is the length of the short bits of radial used to > model it? Alternatively, into what number of short lengths is the > radial under test divided? No problem Reg, here are the data you requested: 0.5 m -- Radial Z = 167.6 - j 161.0 0.6 m -- Radial Z = 146.6 - j 136.3 0.8 m -- Radial Z = 115.9 - j 102.3 1.0 m -- Radial Z = 101.4 - j 79.1 1.2 m -- Radial Z = 89.4 - j 61.5 1.4 m -- Radial Z = 80.9 - j 57.2 1.6 m -- Radial Z = 74.6 - j 35.0 1.8 m -- Radial Z = 70.2 - j 24.1 2.0 m -- Radial Z = 67.2 - j 14.2 Concerning your previous question about the Smith Chart. It is a powerful visual aid which gives a better understanding of what is really happening to the impedances. Exactly what I got out of graphing the data was really only a confirmation of the expected spiral toward Zo. Also the "zero-crossing" which occurs at quarter-wave multiples. Normalization of the data (Division of each complex datum by the complex Zo), and linear graphing, will also provide the same information; including the gradual approach to the normalized Zo of 1 ohm. Where the Smith Chart really proves its worth is in the design of matching networks involving: L, C, R, and transmission lines. It is hard to imagine how anybody could do such design without this aid. I am not sure if anybody actually uses the paper versions these days, but the software equivalent, combined with programs such as (Now Agilent's) Eagleware, are pretty much design lab standards. In this model all segments are a constant 10 cm in length. The number of segments will therefore be L(m)/0.1. Frank Article: 227545 of rec.radio.amateur.antenna From: "Denny" Subject: Re: indoor listening antenna Date: 2 Aug 2006 07:50:14 -0700 Message-ID: <1154530213.924397.80220@i42g2000cwa.googlegroups.com> References: <1154472380.495339.322680@75g2000cwc.googlegroups.com> Some tricks are tape to a #30 wire in the corner of the floor or the ceiling... Or you can form a horizontal loop -around the 4 walls of the room... Run 300 ohm twin lead up to it and use a tuner.. You can form a vertical loop against one wall of the room by running the wire around the corners... Or run a wire under the rugs to the patio door... Screw the end of the wire to the door frame.. Again, use a tuner on the wire. Run a wire out a window or door and up a corner of the wall to the gutter ( if metal) and scew into it... Again, use a tuner... If the gutter is plastic, continue the wire along inside or behind the gutter... A wire out a window and up to a tree (as another mentioned)... Put up a flag pole with a flag.. Pole is, of course, your vertical antenna... Run a coax cable out to it.. Put a mobile antenna on your car... Run a coax from the radio to the car... (remember to unhook before leaving :) denny Article: 227546 of rec.radio.amateur.antenna From: "Jimmie D" References: <1154100643.691199.3530@b28g2000cwb.googlegroups.com> Subject: Re: base loading vertical with roller inductor? Message-ID: Date: Wed, 2 Aug 2006 11:11:08 -0400 "Bill Turner" wrote in message news:a6ppc2tngvog2e9gojhihs9hfms4jvvc9n@4ax.com... > ORIGINAL MESSAGE: > > On 28 Jul 2006 08:30:43 -0700, caheaton@netzero.net wrote: > > >>Is there any >>reason why this wouldnt' work? Has anybody else modified or built an >>antenna using such a system? > > ------------ REPLY SEPARATOR ------------ > > I've done it myself and been quite happy. I used a low RPM reversible > DC motor to tune it remotely from the shack. Works great. > > The only suggestion I would make is to not tune it with any > significant power to it or you could damage the coil by arcing as the > roller moves along. Up to ten or twenty watts should be ok. Keep the > roller clean. > > Bill, W6WRT Hi Bill, can you tell m something about your setup with the roller inductor. I tried it and was not very happy with it. I guess I could have tried a slower motor and it seemed like it require cleaning a couple of times a month. I still have the old stuff around and may try it again if I thought I could get it to work better. Article: 227547 of rec.radio.amateur.antenna From: Walter Maxwell Subject: Re: Radiating Efficiency Message-ID: <6bf1d2p2imm3macj8jk2s7qn1lej84806h@4ax.com> References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> Date: Wed, 02 Aug 2006 11:18:07 -0400 On Wed, 02 Aug 2006 14:03:48 GMT, "Frank's" wrote: > >"Reg Edwards" wrote in message >news:ILadnRpPz7mT7E3ZRVnyiQ@bt.com... >> Frank, snip >Concerning your previous question about the Smith Chart. >It is a powerful visual aid which gives a better understanding >of what is really happening to the impedances. Exactly what >I got out of graphing the data was really only a confirmation >of the expected spiral toward Zo. Also the "zero-crossing" >which occurs at quarter-wave multiples. >Normalization of the data (Division of each complex datum >by the complex Zo), and linear graphing, will also provide >the same information; including the gradual approach to the >normalized Zo of 1 ohm. > >Where the Smith Chart really proves its worth is in the >design of matching networks involving: L, C, R, and >transmission lines. It is hard to imagine how anybody >could do such design without this aid. I am not sure >if anybody actually uses the paper versions these days, >but the software equivalent, combined with programs >such as (Now Agilent's) Eagleware, are pretty much >design lab standards. > >In this model all segments are a constant 10 cm in length. >The number of segments will therefore be L(m)/0.1. > >Frank > May I insert a few words about the Smith Chart? During the period between 1958-59 I designed the entire antenna system and matching harness for the World's first weather satellite, TIROS 1, which was launched April 1, 1960. Four transmitters operating simultaneously on separate frequencies fed the antenna that comprised four crossed monopoles radiating right circular polarization from two transmitters and left circular polarization on the other two frequencies. The point concering the Smith Chart is that the only tools I had for the development of both the antenna system and the matching harness was the Hewlett-Packard HP-805 slotted line for impedance measurements, the slide rule for calculations, and the paper Smith Chart to tell me where I was in the desert. The resolution available with the Chart was sufficient to make the system work successfully. Philip Smith was my hero. Incidentally, the matching harness was fabricated entirely of printed-circuit stripline, and that was 47 years ago. Walt, W2DU Article: 227548 of rec.radio.amateur.antenna Subject: Re: indoor listening antenna From: Dave Oldridge References: <1154472380.495339.322680@75g2000cwc.googlegroups.com> Message-ID: Date: Wed, 02 Aug 2006 15:40:24 GMT "Kris, KC7VWQ" wrote in news:1154472380.495339.322680 @75g2000cwc.googlegroups.com: > My apartment complex recently restricted me to having only antennas on > the inside, and I was wondering what would work best for listening to > the HF and shortwave bands. I live on the first floor, with no access > to an attic. I know a guy who lives on an upper floor who has laid 65 feet of wire around his baseboard. He has a fairly good signal on 75 with it! In your case, you might try running it around the wall at ceiling height. -- Dave Oldridge+ ICQ 1800667 Article: 227549 of rec.radio.amateur.antenna From: ricknj10@hotmail.com (Rick) Subject: Walt, W2DU, and Tiros Message-ID: <44d0c798.313430937@news.optonline.net> References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <6bf1d2p2imm3macj8jk2s7qn1lej84806h@4ax.com> Date: Wed, 02 Aug 2006 15:54:26 GMT On Wed, 02 Aug 2006 11:18:07 -0400, Walter Maxwell wrote: > >During the period between 1958-59 I designed the entire antenna system and >matching harness for the World's first weather satellite, TIROS 1, which was >launched April 1, 1960. > Walt, Could you please tell me a little more about that satellite? Reason I ask is there is a place I am sure you can enlighten us on, called Camp Evans. I know there is still a big dish antenna there, although the wooden structure surrounding it is failing. Supposedly it was used for communicating with Tiros. Is that right? A NJ radio club had a hamfest there in April, and I was able to walk under the antenna and they have some displays there. Supposedly Camp Evans was also the place where the first signals were bounced off the moon, somewhere around 1946. Camp Evans looks like at least parts of it are being renovated. Brookdale Comm. College has some classrooms there, very modern. Oh yes, and on the road leading to Camp Evans (Marconi Road !!) there is a display of the top portion of one of Marconi's towers, and a plaque noting that there were many such towers in the area in the early 1900s. Quite a bit of radio history, in these parts of New Jersey, and I am glad to know one of the pioneers frequents this newsgroup. Not far away, in Holmdel, is where AT&T communicated with Telstar, I believe, about the same time period. The Holmdel facility, home to 6000 Bell Labs employees as recently as1999 has been sold and is going to be demolished. Rick K2XT Article: 227550 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: neighborhood antenna restrictions Date: Wed, 02 Aug 2006 11:56:53 -0400 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <2p50d25p1lrk4qci7eog2lnu7evkhj3f3g@4ax.com> <6370d21pvqocqs2t9p4a3am0mg5ee71tl7@4ax.com> Richard Clark wrote: > On Tue, 01 Aug 2006 20:08:43 -0700, Bill Turner > wrote: > >> ORIGINAL MESSAGE: >> >> On Tue, 01 Aug 2006 18:45:06 -0700, Richard Clark >> wrote: >> >>> Hi Bill, >>> >>> Do they subscribe to "signing statements?" >>> >>> 73's >>> Richard Clark, KB7QHC >> ------------ REPLY SEPARATOR ------------ >> >> Who is "they" and what is a "signing statement"? > > Hi Bill, > > They: the Homeowners Association > signing statement: a Fascist rewriting of a contract already entered > into. > > I can anticipate a "no" in response to my question, and as such the > Homeowners Association ceases to qualify for the current state of the > Fascist art. Of course they aren't fascists. What they are is meddlesome groups who find great joy in uniformity and exercising control over a group. The original intent of such groups was keeping Bubba from parking his '68 Marlin on blocks in the front yard, or using a toilet as a flower planter. What they have evolved into is a way for nosy people to squawk about anything they don't like and now since somebody somewhere doesn't like everything about anything, you have to get the paint color of your crown molding approved, and can't hang clothes on a wash line in the back yard. You can't plant a veggie garden and the plants you can plant are >from an acceptable list. And yet There is nothing evil in such matters. It's a free country, and if some people feel more comfy by giving up some of that freedom so that they can get 5 grand more when they sell the place and move into the nursing home - and give the money to said home, then let 'em have at it. There isn't any law against stupid. -73 de Mike KB3EIA - Article: 227551 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Wed, 02 Aug 2006 09:42:17 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> ORIGINAL MESSAGE: On Wed, 02 Aug 2006 08:54:45 -0400, Michael Coslo wrote: > You would think, wouldn't ya? Yet I find both far left and far right to >be equally meddlesome. Just different tactics. > > > - Mike - ------------ REPLY SEPARATOR ------------ Amen, bro. Bill, W6WRT Article: 227552 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Any info on this type of mobile antenna? Date: Wed, 02 Aug 2006 09:45:29 -0700 Message-ID: References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> On Wed, 2 Aug 2006 06:03:09 -0700, "Harbin Osteen" wrote: >Any info on this type of mobile antenna?: >http://www.gordon.army.mil/AC/Winter/Winter%2001/images/gerc2veh.jpg Hi Harbin, If we are to believe it has one..... Inverted F is the best one I could imagine being possible from this cage. 73's Richard Clark, KB7QHC Article: 227553 of rec.radio.amateur.antenna From: "Frank's" References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <6bf1d2p2imm3macj8jk2s7qn1lej84806h@4ax.com> Subject: Re: Radiating Efficiency Message-ID: Date: Wed, 02 Aug 2006 16:50:39 GMT > May I insert a few words about the Smith Chart? > > During the period between 1958-59 I designed the entire antenna system and > matching harness for the World's first weather satellite, TIROS 1, which > was > launched April 1, 1960. > > Four transmitters operating simultaneously on separate frequencies fed the > antenna that comprised four crossed monopoles radiating right circular > polarization from two transmitters and left circular polarization on the > other > two frequencies. > > The point concering the Smith Chart is that the only tools I had for the > development of both the antenna system and the matching harness was the > Hewlett-Packard HP-805 slotted line for impedance measurements, the slide > rule > for calculations, and the paper Smith Chart to tell me where I was in the > desert. The resolution available with the Chart was sufficient to make the > system work successfully. Philip Smith was my hero. > > Incidentally, the matching harness was fabricated entirely of > printed-circuit > stripline, and that was 47 years ago. Very interesting Walt. Judging by the type of work you were involved in you must be familiar with the classic text by: Matthaei, Young, and Jones. I am not familiar with the HP-805, but probably because most of my earlier lab work was concerned only with HF. I realize that slide rule, pencil, and Smith Chart was the only way in those days. When I started work any intense analysis was done in FORTRAN on main frame computers. One of the hot topics I remember was mini-computers, but never got to see one. I don't think they lasted long, since soon after programmable desktops started to become available. One thing I remember was a guy designing HF antenna tuners, and he used the Smith Chart. What is interesting is that the charts were very large, about 2 ft X 3 ft, and came in pads. Much greater accuracy than the standard chart. I think they may have been published by a company called K-electronics. I used to needle guys in the lab by telling them that Smith was a ham. I now have a nice high res pdf of the Smith Chart, but usually use an electronic version from the "Berne Institute of Engineering". 73, Frank Article: 227554 of rec.radio.amateur.antenna Message-ID: <44D0D8A2.FECE1660@shaw.ca> From: Irv Finkleman Subject: Re: Any info on this type of mobile antenna? References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> Date: Wed, 02 Aug 2006 16:53:43 GMT Harbin Osteen wrote: > > Any info on this type of mobile antenna?: > http://www.gordon.army.mil/AC/Winter/Winter%2001/images/gerc2veh.jpg > > -- > > SeeYaa:) Harbin Osteen KG6URO > > !sdohtem noitpyrcne devorppa-tnemnrevog troppus I > > - The ones on the front fenders are cut up rabbit ears. I'm not sure about the one on top, however it may be some kind of reflector. Irv VE6BP !oot eM -- -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/index.html Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada Article: 227555 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: neighborhood antenna restrictions Date: Wed, 02 Aug 2006 09:54:05 -0700 Message-ID: References: <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <2p50d25p1lrk4qci7eog2lnu7evkhj3f3g@4ax.com> <6370d21pvqocqs2t9p4a3am0mg5ee71tl7@4ax.com> On Wed, 02 Aug 2006 11:56:53 -0400, Michael Coslo wrote: > Of course they aren't fascists. What they are is meddlesome groups who >find great joy in uniformity and exercising control over a group. > Hi Mike, Sounds like we've discovered the last of the proto-neocon republicans in their natural preserve for endangered species. Amusing to contemplate that they share the same future prospects as the Spotted Owl - courtesy of the social engineering bulldozers coming out of the beltway. ;-) 73's Richard Clark, KB7QHC Article: 227556 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: indoor listening antenna Date: Wed, 02 Aug 2006 10:00:44 -0700 Message-ID: References: <1154472380.495339.322680@75g2000cwc.googlegroups.com> On 1 Aug 2006 15:46:20 -0700, "Kris, KC7VWQ" wrote: > I was wondering what would work best for listening Hi Kris, Staying inside the apartment has you soaking in noise. You will need an antenna filter - a cheap, meterless three knob unit will do. Look into getting it outside, possibly with a downspout. Check into RG-178, a thin coax that borders on invisible. Put a choke at the end that sees an ad-hoc dipole. 73's Richard Clark, KB7QHC Article: 227557 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: base loading vertical with roller inductor? Date: Wed, 02 Aug 2006 10:12:04 -0700 Message-ID: References: <1154100643.691199.3530@b28g2000cwb.googlegroups.com> ORIGINAL MESSAGE: On Wed, 2 Aug 2006 11:11:08 -0400, "Jimmie D" wrote: >Hi Bill, can you tell m something about your setup with the roller inductor. >I tried it and was not very happy with it. I guess I could have tried a >slower motor and it seemed like it require cleaning a couple of times a >month. I still have the old stuff around and may try it again if I thought I >could get it to work better. ------------ REPLY SEPARATOR ------------ At the time I lived in the Seattle area so waterproofing was a must. I built a plywood box with a plexiglas front and sealed it with silicone. I used it for a couple of years and never had to clean the roller inductor. One thing I didn't mention but should have is to have most of the loading inductance in a separate high Q coil, and use the roller only for tuning. IOW, don't try to use the roller for the entire loading coil or it will tune too fast and probably won't be very high Q either. As with mobile antennas, a center coil is best, or at least as high off the ground as practical. If you don't have an MFJ SWR analyzer or the equivalent, buy or borrow one. I would not attempt this kind of project without one! The motor was one I got from All Electronics in California. They seem to have lots of surplus ones available. Something around five RPM would be about right. They call them "gearhead" or something like that because they have the reduction gears built in. Does that answer your questions? Bill, W6WRT Article: 227558 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Radiating Efficiency Date: Wed, 02 Aug 2006 10:27:05 -0700 Message-ID: <2tn1d2tue86lehcuci8tle2edggo1qgufp@4ax.com> References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <6bf1d2p2imm3macj8jk2s7qn1lej84806h@4ax.com> On Wed, 02 Aug 2006 16:50:39 GMT, "Frank's" wrote: >"Berne Institute of Engineering" Hi Frank, Reverse engineering this clue, I've found the author is Prof. F. Dellsperger, and that his Smith Chart software can be found at: http://www.fritz.dellsperger.net/downloads.htm 73's Richard Clark, KB7QHC Article: 227559 of rec.radio.amateur.antenna From: "Antonio Vernucci" Subject: Question on carbon fibre fishing rod Date: Wed, 2 Aug 2006 19:32:38 +0200 Message-ID: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> I plan to use a carbon fibre fishing rod as a stealth antenna at my = summer QTH . The rod would just be a mechanical support, while the = proper antenna would consist of a copper wire replacing the fishing wire = (i.e. it would run on one side of the rod, parallel to it) I am getting worried by the fact that the carbon fibre rod may dissipate = significant power because of the RF current induced in it (the rod would = be very close to the radiating wire) and of its non-negligible = resistance. I had occasion to broadly measure the rod DC resistance with an ohm x = 1000 ohmeter, at about 4 inches of distance on the rod, and the meter = reading was about full scale (low resistance). But the resistance range = I am worried about is in the order of a few ohms, so my measurement does = not tell much. In any case, reading some articles on carbon fibre on the = Internet, I learned that the rod must anyway have a few ohms of = resistance, quite a dangerous range. The real question is: shall I expect that the copper wire will induce RF = current on the rod that would cause power dissipation in it? Does anyone = have experience with such an arrangement? Please do not suggest me to use a fiberglass rod instead because, for a = given length, it would be much thicker and heavier (too much). 73 Tony I0JX - Rome, Italy Article: 227560 of rec.radio.amateur.antenna From: "Frank's" References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <6bf1d2p2imm3macj8jk2s7qn1lej84806h@4ax.com> <2tn1d2tue86lehcuci8tle2edggo1qgufp@4ax.com> Subject: Re: Radiating Efficiency Message-ID: Date: Wed, 02 Aug 2006 17:45:49 GMT "Richard Clark" wrote in message news:2tn1d2tue86lehcuci8tle2edggo1qgufp@4ax.com... > On Wed, 02 Aug 2006 16:50:39 GMT, "Frank's" > wrote: > >>"Berne Institute of Engineering" > > Hi Frank, > > Reverse engineering this clue, I've found the author is Prof. F. > Dellsperger, and that his Smith Chart software can be found at: > http://www.fritz.dellsperger.net/downloads.htm > > 73's > Richard Clark, KB7QHC Thanks Richard, I had recently tried to locate a source for this program, but could no longer find it. I see he has updated the program so will try the upgrade. I see he also has a lot of other stuff that looks interesting. 73, Frank, VE6CB Article: 227561 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> Subject: Re: Radiating Efficiency Date: Wed, 2 Aug 2006 18:53:14 +0100 Message-ID: > No problem Reg, here are the data you requested: > > 0.5 m -- Radial Z = 167.6 - j 161.0 > 0.6 m -- Radial Z = 146.6 - j 136.3 > 0.8 m -- Radial Z = 115.9 - j 102.3 > 1.0 m -- Radial Z = 101.4 - j 79.1 > 1.2 m -- Radial Z = 89.4 - j 61.5 > 1.4 m -- Radial Z = 80.9 - j 57.2 > 1.6 m -- Radial Z = 74.6 - j 35.0 > 1.8 m -- Radial Z = 70.2 - j 24.1 > 2.0 m -- Radial Z = 67.2 - j 14.2 > ===================================== Frank, Thank you for the above. Can you do 36 radials from 0.6 to 8.0 metres in increments of 0.2 metres? Must be the same input data as before :- F = 8.07 MHz, Ground = 150,16 Radial diameter = 1.64mm, Depth = 25mm. ---- Reg. Article: 227562 of rec.radio.amateur.antenna From: "hasan schiers" Subject: Re: Radiating Efficiency Date: Wed, 2 Aug 2006 12:59:01 -0500 Message-ID: References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <2_OdnX7zdY6gVFzZRVny3w@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> Reg, I have taken Frank's numbers from NEC-4 (that he sent me) and compared the results with Radials_3. Here is what I found: NEC-4 Parameters (in parens are the values I get with Radials_3, note the differences are LARGE) Height 20 m; Radials 15 m; 24 radials at 15 degree intervals; Radials 25 mm below ground; All wires # 14 AWG copper; (I USED 2mm wire) Gnd. Er = 25, Resistivity 25 ohm-m; Resonant Frequency 3.64 MHz, and; (Radial_3 shows Resonant Freq of 3.750) Zin = 41.32 + j 0.156466 ohms at 3.64 MHz. (34.17 ohms and j -24.6) If I change the Freq in Radial_3 to 3.750, I get Zin = 37.41 and j -0.0. That is 110 KHz difference for the same antenna and ground characteristics. Not very good agreement. ================================================= Now, on to the real question I have been asking for a week: Does the current along the radials fall off as rapidly as Radial_3 predicts? I used the numbers from the above antenna, (supplied by Frank from NEC-4) and compared them to what Radial_3 says for the same length. I do not have numbers showing a 5 meter radial for NEC-4 and a 5 meter radial for Radial_3. What I am presenting is the current along the full radial in NEC-4, vs. the current in a radial of specified length in Radial_3. Length is in meters. Since we are using ratios, I only used the integer and two decimal places for the current in my calculations. All values for current are actually what is presented * 10^-2 Length Current NEC-4 (dB) Radial_3 (dB) 0 9.15 N/A N/A 1 8.37 0.77 6.2 2 6.98 2.35 12.4 3 5.63 4.22 18.6 4 4.55 6.07 24.7 5 3.57 8.17 30.9 6 3.00 9.69 37.1 7 2.54 11.13 43.3 8 2.16 12.54 49.5 9 1.84 13.93 55.7 10 1.60 15.15 61.8 11 1.46 15.94 68.0 12 1.41 16.24 74.2 13 1.36 16.56 80.4 14 1.04 18.89 86.6 14.75 0.26 30.93 91.2 Notice at a lenght of 4 meters, Radial_3 is showing 24.7 dB of attenuation of the current, while NEC-4 is only showing 6 dB...not even close. Notice throughout the lengths from 3 to 11 meters, the difference between Radial_3 nd NEC-4 is a pretty consistent 4X, i.e, Radial_3 is showing four times the attenuation at a given length that NEC-4 is showing. Patterns like this in data are rarely the result of chance. Maybe this will lead to a resolution of the problem. If Reg's threshold of 25 dB attenuation is reasonable (at which point adding additional length is of very little value), then NEC-4 says for this particular set of variables that we don't attain anything near 25 dB current attenuation along the length until we get to greater than 14 meters (and the wire is only 15 meters long!) How could the current in a 4 meter radial drop by 25 dB within its length? So, I'm left with two questions: 1. Extra wire....what extra wire? It looks like one needs the entire 15 meter radial wire, not some 4 meter stubby....at least according to NEC-4. 2. Why such a discrepancy in resonant freq between NEC-4 and Radial_3? Unless someone else can point out an error in the analysis, it appears that the transmission line model that Reg is using to predict rate of current drop along the radial vs. length is either the wrong model, or the wrong application thereof. NEC-4 just doesn't seem to support the rapid current fall-off that Radial_3 predicts. BL&E says it ain't so. Tom, W8JI, says his measurements say it ain't so. NEC-4 appears to say "it ain't so". If I were a betting person, I'd say it ain't so. Back to the drawing board? In the mean time, anyone putting in a radial field woud appear to be better served by the references in this thread to "optimizing radial systems", I think by K3LC...it's in several antenna books. 73, p.s. How all this fits into efficiency someone else can analyze, but it can't be good. ...hasan, N0AN Article: 227563 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Question on carbon fibre fishing rod Date: Wed, 02 Aug 2006 11:07:29 -0700 Message-ID: References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> On Wed, 2 Aug 2006 19:32:38 +0200, "Antonio Vernucci" wrote: >I plan to use a carbon fibre fishing rod as a stealth antenna at my = >summer QTH . Hi Tony, What frequency? 73's Richard Clark, KB7QHC Article: 227564 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Wed, 2 Aug 2006 20:22:59 +0200 Message-ID: <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> 7 to 28 MHz. Tony "Richard Clark" ha scritto nel messaggio = news:vdq1d25pk9o5po8q8s6ngloabbim41fah1@4ax.com... > On Wed, 2 Aug 2006 19:32:38 +0200, "Antonio Vernucci" > wrote: >=20 > >I plan to use a carbon fibre fishing rod as a stealth antenna at my = =3D > >summer QTH . >=20 > Hi Tony, >=20 > What frequency? >=20 > 73's > Richard Clark, KB7QHC Article: 227565 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Question on carbon fibre fishing rod Date: Wed, 02 Aug 2006 12:13:26 -0700 Message-ID: References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> On Wed, 2 Aug 2006 20:22:59 +0200, "Antonio Vernucci" wrote: >7 to 28 MHz. Hi Tony, Presuming a length of 3M, and you can tune the antenna; then you may lose a few dB. As for heating. The exposure to sun (if the rod is black) will probably create more heat than the RF. You need to provide a resistance reading with more resolution than 0 Ohms on the 1000 Ohms range. 73's Richard Clark, KB7QHC Article: 227566 of rec.radio.amateur.antenna From: Cecil Moore Subject: Rule of Thumb for coax chokes Message-ID: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> Date: Wed, 02 Aug 2006 19:17:17 GMT Based on some calculations I did today, I am offering an original rule of thumb (as far as I know). Regarding a coax choke, when deciding how many turns of coax to put on a 2 liter pop bottle at two turns per inch, one needs to avoid the self-resonant frequency. So don't put more turns on the choke than the number of meters in a wavelength, e.g. no more than 20 turns on 20m, no more than 6 turns on 6m. Backup calculations will be published on my web page. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227567 of rec.radio.amateur.antenna From: Walter Maxwell Subject: Re: Radiating Efficiency Message-ID: <9dv1d29fqimbktk1fp7fikko4tufrc19sn@4ax.com> References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <6bf1d2p2imm3macj8jk2s7qn1lej84806h@4ax.com> Date: Wed, 02 Aug 2006 15:32:25 -0400 On Wed, 02 Aug 2006 16:50:39 GMT, "Frank's" wrote: >> May I insert a few words about the Smith Chart? >> >> During the period between 1958-59 I designed the entire antenna system and >> matching harness for the World's first weather satellite, TIROS 1, which >> was >> launched April 1, 1960. >> >> Four transmitters operating simultaneously on separate frequencies fed the >> antenna that comprised four crossed monopoles radiating right circular >> polarization from two transmitters and left circular polarization on the >> other >> two frequencies. >> >> The point concering the Smith Chart is that the only tools I had for the >> development of both the antenna system and the matching harness was the >> Hewlett-Packard HP-805 slotted line for impedance measurements, the slide >> rule >> for calculations, and the paper Smith Chart to tell me where I was in the >> desert. The resolution available with the Chart was sufficient to make the >> system work successfully. Philip Smith was my hero. >> >> Incidentally, the matching harness was fabricated entirely of >> printed-circuit >> stripline, and that was 47 years ago. > >Very interesting Walt. Judging by the type of work you were involved in >you must be familiar with the classic text by: Matthaei, Young, and Jones. >I am not familiar with the HP-805, but probably because most of my >earlier lab work was concerned only with HF. I realize that slide rule, >pencil, and Smith Chart was the only way in those days. When I started >work any intense analysis was done in FORTRAN on main frame >computers. One of the hot topics I remember was mini-computers, >but never got to see one. I don't think they lasted long, since soon >after programmable desktops started to become available. > >One thing I remember was a guy designing HF antenna tuners, and he >used the Smith Chart. What is interesting is that the charts were >very large, about 2 ft X 3 ft, and came in pads. Much greater >accuracy than the standard chart. I think they may have been published >by a company called K-electronics. I used to needle guys in the lab >by telling them that Smith was a ham. > >I now have a nice high res pdf of the Smith Chart, but >usually use an electronic version from >the "Berne Institute of Engineering". > >73, > >Frank > Thanks for the nice response, Frank, Walt Article: 227568 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Wed, 2 Aug 2006 21:33:33 +0200 Message-ID: <44d0fe0d$0$35074$4fafbaef@reader4.news.tin.it> > Hi Tony, >=20 > Presuming a length of 3M the rod is 8 meter long , and you can tune the antenna; then you may > lose a few dB. hard to tell how many dB one would loose, until the power loss mechanism = via the rod coupling is understood. I would need to find somebody who = had occasion to test that configuration, otherwise I will have to anyway = buy the rod (about 100$) and make the test myself =20 =20 > As for heating. The exposure to sun (if the rod is black) will > probably create more heat than the RF. I am not worried at all of rod heating, but of RF power loss > You need to provide a > resistance reading with more resolution than 0 Ohms on the 1000 Ohms > range. There are many articles on the Internet that suggest a resistance in the = order of one ohm or so. But knowing precisely how many ohms the rod = shows woud not help much, as, again, until the loss mechanism is not = characterized, noone can stell something sensible =20 > 73's welcome Article: 227569 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: Question on carbon fibre fishing rod Date: Wed, 02 Aug 2006 12:55:35 -0700 Message-ID: References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> ORIGINAL MESSAGE: On Wed, 2 Aug 2006 19:32:38 +0200, "Antonio Vernucci" wrote: > >I am getting worried by the fact that the carbon fibre rod may dissipate significant power because of the RF current induced in it (the rod would be very close to the radiating wire) and of its non-negligible resistance. ------------ REPLY SEPARATOR ------------ The only way to know for sure is to try it. Give it a few watts for a few seconds and feel for heat. If there is any at all, go to plan B. If there is no heat, give it 100 watts for a few seconds. Still no heat? Give it full power for a longer period. Still no heat? You have your answer. Bill, W6WRT Article: 227570 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 2 Aug 2006 12:57:25 -0700 Message-ID: <1154548645.376883.303310@m73g2000cwd.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> If you can measure the resistance at more than one point on the surface of the rod, does this imply that the rod surface is conductive everywhere along its length? If you could attach the wire to the rod so that it touches everywhere along the length, then the current would divide between the rod and the wire according to their respective resistance per length (most of the current would flow in the wire) and the currents induced in the pole would be in phase with the currents induced in the wire. I think it would help to have the wire attached at least at the bottom of the pole and the top of the pole. If you attach the wire only at the top and ground the bottom of the pole, you make a rather lossy folded monopole. If you attach the wire at both the top and bottom of the pole and insulate the whole structure >from ground, it's more like a cage monopople with one lossy wire and one good wire. Dan Article: 227571 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Question on carbon fibre fishing rod Date: Wed, 02 Aug 2006 12:57:47 -0700 Message-ID: References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> <44d0fe0d$0$35074$4fafbaef@reader4.news.tin.it> On Wed, 2 Aug 2006 21:33:33 +0200, "Antonio Vernucci" wrote: >hard to tell how many dB one would loose, until the power loss mechanism via the rod coupling is understood. I would need to find somebody who had occasion to test that configuration, otherwise I will have to anyway buy the rod (about 100$) and make the test myself Hi Tony, That is the only sure way of knowing. Modeling with EZNEC will certainly reveal obvious problems. >> As for heating. The exposure to sun (if the rod is black) will >> probably create more heat than the RF. > >I am not worried at all of rod heating, but of RF power loss Same thing. >There are many articles on the Internet that suggest a resistance in the order of one ohm or so. But knowing precisely how many ohms the rod shows woud not help much, as, again, until the loss mechanism is not characterized, noone can stell something sensible Total resistance over 8 meters is 1 Ohm? If so, it does not look like a problem. 1 Ohm every 10cM? Still does not look like a problem. Download EZNEC and do your own modeling. 73's Richard Clark, KB7QHC Article: 227572 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> Subject: Re: Rule of Thumb for coax chokes Date: Wed, 2 Aug 2006 20:57:26 +0100 Message-ID: <3bCdnRPeEcZBnkzZRVnysw@bt.com> Why avoid the self-resonant frequency? That's the frequency at which the choking impedance is a maximum. ---- Reg Article: 227573 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 2 Aug 2006 13:24:47 -0700 Message-ID: <1154550287.570802.313110@p79g2000cwp.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Richard, Can you assign different conductivities to different wires in EZNEC? I don't think you can. You could distribute the resistance, 1 load per segment each having a resistance of 1/#segments of the total. It seems important for coupling to have a realistic diameter (fat) wire for the carbon fiber pole, but it needs to be lossy. A load taper from bottom (large tubing, lower resistance) to top (small tubing, high resistance) would be easy to implement as well. This is probably only worth it if it seems that the loss will be nonnegligible, but it could take into account the effect of the element current distribution on loss. Dan Article: 227574 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> Subject: Re: Rule of Thumb for coax chokes Date: Wed, 2 Aug 2006 21:28:59 +0100 Message-ID: Cec, Suppose you havn't got a pop bottle but only a length of plastic drain pipe of different diameter. You will need a different rule of thumb for every contingency. ---- Reg. Article: 227575 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> <44d0fe0d$0$35074$4fafbaef@reader4.news.tin.it> <1154548645.376883.303310@m73g2000cwd.googlegroups.com> Subject: Re: Question on carbon fibre fishing rod Date: Wed, 2 Aug 2006 22:48:04 +0200 Message-ID: <44d10f83$0$35078$4fafbaef@reader4.news.tin.it> Hi Dan > If you can measure the resistance at more than one point on the = surface > of the rod, does this imply that the rod surface is conductive > everywhere along its length? I am not sure having fully understood your remark. I presume that, the = materal being homogeneous, the rod surface is conductive everywhere the = same way. The various elements of the rod touch each other, so there is = electrical continuity along the whole rod. Clearly, toward the rod top, = resistance will be higher due to the thinner diameter =20 > If you could attach the wire to the rod so that it touches everywhere > along the length, then the current would divide between the rod and = the > wire according to their respective resistance per length (most of the > current would flow in the wire) and the currents induced in the pole > would be in phase with the currents induced in the wire. I agree that currents would divide between the rod and the wire = according to their respective resistance, but this is not my main worry = as the very low-resistance copper wire would nearly fully bypass the rod = resistance. What I am instead worried about is that, the rod being = thick, the RF current may not be the same along the rod circumference. = In other words, at the point of contact between the rod and the copper = wire, the rod current could be lower than that at its opposite side. = Such extra current could develop due to the rod electromagnetic coupling = with the radiating wire. However, I am not sure whether my reasoning = makes real sense >=20 > I think it would help to have the wire attached at least at the bottom > of the pole and the top of the pole. > If you attach the wire only at the top and ground the bottom of the > pole, you make a rather lossy folded monopole. If you attach the wire > at both the top and bottom of the pole and insulate the whole = structure > from ground, it's more like a cage monopople with one lossy wire and > one good wire. My idea is to have the wire attached at both the bottom and the top of = the rod as you suggest. The bottom copper lead would also be connected = to the center conductor of the coaxial feed cable (the cable braid would = instead be connected to the radial system). Now an interesting case. Suppose that the copper wire is instead kept = fully insulated from the rod (though very close to it). Would you expect = power loss to occur in the conductive rod due to RF currents flowing = through the rod due to its electromagnetic coupling with the radiating = wire? 73 Tony I0JX Article: 227576 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> Message-ID: <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Date: Wed, 02 Aug 2006 20:53:20 GMT Reg Edwards wrote: > Why avoid the self-resonant frequency? > That's the frequency at which the choking impedance is a maximum. Personal preference - I would rather the choking impedance be at maximum reactance rather than at maximum resistance. I think that saves a little bit of power. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227577 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> Message-ID: Date: Wed, 02 Aug 2006 20:59:58 GMT Reg Edwards wrote: > Suppose you havn't got a pop bottle but only a length of plastic drain > pipe of different diameter. Then I use my EXCEL spreadsheet which allows variation in the number of turns per inch and diameter of the coil. If you would like a copy, it can be downloaded from http://www.qsl.net/w5dxp/Corum1.xls > You will need a different rule of thumb for every contingency. 2 liter pop bottles are in abundance in the US. If a coil form is used for a coax choke, that's the most likely. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227578 of rec.radio.amateur.antenna From: "Bob Agnew" References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Subject: Re: neighborhood antenna restrictions Message-ID: Date: Wed, 2 Aug 2006 14:04:30 -0700 Do you know of any place in Southern California that doesn't have such restrictions? "Bill Turner" wrote in message news:43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com... > ORIGINAL MESSAGE: > > On Tue, 01 Aug 2006 16:20:27 -0400, Michael Coslo > wrote: > >> Why on earth would anyone live in one of those places? And yes there >>are alternatives. I live in a development that doesn't have that that >>kind of insane meddling going on. I can have a tower even, as long as it >>has enough room to fall down within my yard and not hit the neighbors. > > ------------ REPLY SEPARATOR ------------ > > Couldn't agree more. Move away from the Fascist Homeowners Association > and get in an area where people know enough to leave each other alone! > Your blood pressure will go down, your enjoyment of life will go up > and you might live long enough to Work All Stations. > > Ok, a tad exaggerated but you get the idea. > > 73, BIll W6WRT Article: 227579 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: neighborhood antenna restrictions References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Message-ID: Date: Wed, 02 Aug 2006 21:14:21 GMT Bob Agnew wrote: > Do you know of any place in Southern California that doesn't have such > restrictions? One probably has to move away from the left coast. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 227580 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> <44d0fe0d$0$35074$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Wed, 2 Aug 2006 23:17:02 +0200 Message-ID: <44d1164e$0$35074$4fafbaef@reader4.news.tin.it> > That is the only sure way of knowing. Modeling with EZNEC will > certainly reveal obvious problems. Yes, that is a possibility, although properly interpreting EZNEC results = is often not easy. I will try anyway > Total resistance over 8 meters is 1 Ohm? If so, it does not look like > a problem. 1 Ohm every 10cM? Still does not look like a problem. Well, one ohm is just the order of magnitude. It will be neither one = tenth of a ohm, nor 10 ohms. Moreover resistance will vary along the rod = due to the very significant diameter change, and RF current is not = constant along the rod either. I am beginning to fear that the only way = to really understand how things go is to buy the rod, build the antenna, = apply high power (> 1kW) to it for 15 minutes, and the touch the rod to = determine whether its temperature has raised somewhat. 73 Tony I0JX Article: 227581 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> Message-ID: Date: Wed, 02 Aug 2006 21:17:04 GMT Cecil Moore wrote: > Reg Edwards wrote: > >> Suppose you havn't got a pop bottle but only a length of plastic drain >> pipe of different diameter. > > > Then I use my EXCEL spreadsheet which allows variation > in the number of turns per inch and diameter of the coil. > If you would like a copy, it can be downloaded from > > http://www.qsl.net/w5dxp/Corum1.xls > >> You will need a different rule of thumb for every contingency. > > > 2 liter pop bottles are in abundance in the US. If a coil > form is used for a coax choke, that's the most likely. But then you have to drink 2 liters of wet, sticky, gooey, sickeningly sweet, soda pop. 73, Tom Donaly, KA6RUH Article: 227582 of rec.radio.amateur.antenna From: "Reg Edwards" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Wed, 2 Aug 2006 22:22:32 +0100 Message-ID: Tony, The best thing to do is insulate the wire from the rod at the top and bottom. Space the wire from the rod by one or two centimetres. The rod will not be near to 1/2-wave resonance and the antenna will behave very much as if the rod did not exist. Remember that loss induced in the rod will be negligible when the resistivity of the rod is high, or is also very low. I would imagine the loss would be greatest when the end-to-end rod resistance is in the order of 150 ohms. But loss will be induced in the rod only when the rod is near to 1/2-wave resonant. ---- Reg. Article: 227583 of rec.radio.amateur.antenna Message-ID: <44D118E3.6050109@fuse.net> Date: Wed, 02 Aug 2006 17:28:03 -0400 From: john Subject: Re: VENT Re: (OT) : Democrat's Out-Sourcing "Hate America" To Canada References: <129m9ijcnshm47f@corp.supernews.com> <129ofcclvejs22f@corp.supernews.com> <0bjo92p0h2dfqcum243lc3u1mqv49nu10h@4ax.com> <1152720850.662591.37690@b28g2000cwb.googlegroups.com> <1152839909.231750.229790@35g2000cwc.googlegroups.com> <1152848674.361536.176700@h48g2000cwc.googlegroups.com> Paul Hinman wrote: > J. D. B. wrote: >> Well at least your estate will get to keep your life savings. If you >> get sick late in the year, and the healthcare facility/hospital shut >> down for the rest of the year because it ran out of government money >> (a typical scenario in Canada), there will be no one to give you any >> care and you'll just die. But hey, your life savings will still be >> intact! Is socialized health care great or what? >>> >>> - At least in Canada you get to keep >>> - your life savings if you get sick. >>> > I am a Canadian with serious chronic health problems and I have much > more experience with the health system than I would like to have, I > have come close being a silent key several times, I am sure that there > are some who feel that is too bad that I was allowed to breed before my > medical problems became obvious. In the minds of some I suppose that I > have peed in the genetic pool. > > I have never heard of a Canadian hospital shutting down because the > money did not last until fiscal year end. While there are some > weaknesses in our system such as delays in elective procedures but when > the sand was running out of the hour glass there was always a system to > help me out. Here everyone can get insured, there is an option to opt > out of medicare but who would? > > Think of the overhead that American doctors face having to deal with > multiple insurance companies, each with different forms and procedures. > Think of the people who can't get medical insurance no matter what the > cost. Think of those who don't have because they can't afford it. And > then there are those who exercise their right not have it. > > In a situation where people get treated but can't afford to pay, the > rates for everyone else must go up to compensate. > > Canada is not perfect but it is a pretty nice place to live and we try > to contribute as best we can. > > By the way, if I were an American I would vote republican but I am not a > single issue voter so don't construe that to mean that I from the far > right wing. Consider me a fiscal conservative with a social conscience. > > -- > Paul S. Hinman - VE6LDS > long West 113 deg 27 min 20 sec > lat North 53 deg 27 min 3 sec > Maidenhead Locator DO33gk > > Canada is a perfectly wonderful place. The original posting title "Democrat's Out-Sourcing 'Hate America' To Canada !" sounds like it is right out of the Colbert Report. In America today, to be fiscally conservative, one cannot be a Republican. What's the deficit today? 3 trillion? 9 trillion? Who gets a tax cut? the middle class? not lately. Praise the Lord and pass the exemptions. Article: 227584 of rec.radio.amateur.antenna Message-ID: <44D11A49.8030404@fuse.net> Date: Wed, 02 Aug 2006 17:34:01 -0400 From: john Subject: Re: neighborhood antenna restrictions References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <2p50d25p1lrk4qci7eog2lnu7evkhj3f3g@4ax.com> <6370d21pvqocqs2t9p4a3am0mg5ee71tl7@4ax.com> Michael Coslo wrote: > Richard Clark wrote: >> On Tue, 01 Aug 2006 20:08:43 -0700, Bill Turner >> wrote: >> >>> ORIGINAL MESSAGE: >>> >>> On Tue, 01 Aug 2006 18:45:06 -0700, Richard Clark >>> wrote: >>> >>>> Hi Bill, >>>> >>>> Do they subscribe to "signing statements?" >>>> >>>> 73's >>>> Richard Clark, KB7QHC >>> ------------ REPLY SEPARATOR ------------ >>> >>> Who is "they" and what is a "signing statement"? >> >> Hi Bill, >> >> They: the Homeowners Association >> signing statement: a Fascist rewriting of a contract already entered >> into. >> >> I can anticipate a "no" in response to my question, and as such the >> Homeowners Association ceases to qualify for the current state of the >> Fascist art. > > uniformity and exercising control over a group. You just defined fascism. > > The original intent of such groups was keeping Bubba from parking > his '68 Marlin on blocks in the front yard, or using a toilet as a > flower planter. > It's a free country, > and if some people feel more comfy by giving up some of that freedom > then they, too, are fascists. Article: 227585 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Date: Wed, 2 Aug 2006 22:42:51 +0100 Message-ID: "Cecil Moore" wrote in message news:4h8Ag.521$%j7.331@newssvr29.news.prodigy.net... > Reg Edwards wrote: > > Why avoid the self-resonant frequency? > > That's the frequency at which the choking impedance is a maximum. > > Personal preference - I would rather the choking impedance > be at maximum reactance rather than at maximum resistance. > I think that saves a little bit of power. > -- > 73, Cecil http://www.qsl.net/w5dxp ===================================== But Cecil, maximum resistance, maximum reactance and maximum impedance all occur at the same resonant frequency. And at the resonant frequency minimum loss occurs in the choke anyway. There's negligible loss of power in the choke left to save. ---- Reg. Article: 227586 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 2 Aug 2006 14:46:18 -0700 Message-ID: <1154555178.548566.311570@75g2000cwc.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Antonio, The carbon fiber rod is very thin with respect to a wavelength. There won't be any significant of the RF current variation around the circumference of the rod. If you have the wire insulated from, but closely spaced to the carbon rod. Then the rod becomes a parasitic element ONLY coupled to the wire via the fields. If the rod is insulated from ground by a base insulator there is probably no problem. I think the current will still divide approximately the same way. There may be some subtle differences. The situation where you allow the rod to touch the ground (or worse, the ground radial system) is drastically different. Now you have, instead of a monopole, a weird parallel transmission line. A closed top gives a folded monopole, but opening the top (insulating the wire >from the pole everywhere) doesn't change the fact that it's a transmission line. Imagine the following: the top is open, you're operating on 30m where the pole and wire are very close to 1/4 wavelength long. This gives a very *low* impedance at the bottom of your open transmission line stub. I think a great deal of differential mode current could flow in this case, and I think it would cause a good amount of loss. I think your plan of having the wire connected to the pole at top and bottom is sufficient if you have a good base insulator. Dan P.S. I wondered about the surface of the rod because I thought perhaps there would be an outer nonconductive layer of thin plastic film to protect from carbon fiber splinters. If there's no such film, then spiralling the wire around the pole or clamping it periodically to the pole will make for good contact everywhere. Article: 227587 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: neighborhood antenna restrictions Date: Wed, 02 Aug 2006 14:48:49 -0700 Message-ID: References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Cecil Moore wrote: > Bob Agnew wrote: > >> Do you know of any place in Southern California that doesn't have such >> restrictions? > > > One probably has to move away from the left coast. :-) Yes, move away from the coast until you see sand (not sea sand). ac6xg Article: 227588 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 2 Aug 2006 14:51:11 -0700 Message-ID: <1154555471.361131.144930@h48g2000cwc.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> In calm air, what's the temperature rise you'd expect for a tolerable (1dB?) amount of loss with 1kW input power? Incidentally, I don't think you'll run out of ham radio uses for an 8m carbon fiber rod, so I'd just buy it and build. I think I want one now, too ;-) 73, Dan > I am beginning to fear that the only way to really understand how things go is to buy the >rod, build the antenna, apply high power (> 1kW) to it for 15 minutes, and the touch the >rod to determine whether its temperature has raised somewhat. > > 73 > > Tony I0JX Article: 227589 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 2 Aug 2006 14:54:14 -0700 Message-ID: <1154555654.618018.192280@i42g2000cwa.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Or if it is 1/4-wave resonant and is in relatively low-resistance contact with the groundplane. Dan > But loss will be induced in the rod only when the rod is near to > 1/2-wave resonant. > ---- > Reg. Article: 227590 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Rule of Thumb for coax chokes Date: 2 Aug 2006 14:57:17 -0700 Message-ID: <1154555837.226018.58110@i3g2000cwc.googlegroups.com> References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> I like to drink soda water from 2l bottles with a splash of lemon juice; sounding pretty good right now given that it's 97F in Maryland and the weather this week is, as per the NWS, "Excessive Heat" Dan > > But then you have to drink 2 liters of wet, sticky, gooey, sickeningly > sweet, soda pop. > 73, > Tom Donaly, KA6RUH Article: 227591 of rec.radio.amateur.antenna From: "kd5sak" References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Subject: Re: neighborhood antenna restrictions Message-ID: <9m9Ag.621$FN2.39@newssvr14.news.prodigy.com> Date: Wed, 02 Aug 2006 22:07:01 GMT "Jim Kelley" wrote in message news:ear6k4$qr2$1@news.service.uci.edu... > Cecil Moore wrote: > >> One probably has to move away from the left coast. :-) > > Yes, move away from the coast until you see sand (not sea sand). > > ac6xg > Think the old fashioned method of getting away from the coastal area was to carry an oar over one shoulder and hike 'til someone asked, "Whats that thing on your shoulder?" Can't say personally, I've always lived near Americas heartland (Used to be called the Great American Desert before they found it was a wheat growers paradise). Harold KD5SAK Article: 227592 of rec.radio.amateur.antenna From: "Lee" Subject: Magloop capacitor padding? Message-ID: Date: Wed, 02 Aug 2006 22:09:43 GMT Hi!.... I`ve just built a magloop 5`square and i find the variable cap only tunes down to 4.45mhz.. can i pad the cap out with a coaxial ur213 stub to reach 3.5mhz ???.... Lee.......G6ZSG..... (The 1metre loop works fine - 15 to 7mhz ).. :-) Article: 227593 of rec.radio.amateur.antenna From: "Jerry Martes" References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> Subject: Re: Any info on this type of mobile antenna? Message-ID: Date: Wed, 02 Aug 2006 22:18:18 GMT "Harbin Osteen" wrote in message news:1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com... > Any info on this type of mobile antenna?: > http://www.gordon.army.mil/AC/Winter/Winter%2001/images/gerc2veh.jpg > > -- > > SeeYaa:) Harbin Osteen KG6URO > > !sdohtem noitpyrcne devorppa-tnemnrevog troppus I Hi Harbin Perhaps it is an inverted lawnchair antenna. It might be one of those mobile lawnchairs that the Israelis are trying to eliminate from Lebanon. encrypted Article: 227594 of rec.radio.amateur.antenna From: Walter Maxwell Subject: Re: Walt, W2DU, and Tiros Message-ID: References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <6bf1d2p2imm3macj8jk2s7qn1lej84806h@4ax.com> <44d0c798.313430937@news.optonline.net> Date: Wed, 02 Aug 2006 18:29:03 -0400 On Wed, 02 Aug 2006 15:54:26 GMT, ricknj10@hotmail.com (Rick) wrote: >On Wed, 02 Aug 2006 11:18:07 -0400, Walter Maxwell >wrote: > >> >>During the period between 1958-59 I designed the entire antenna system and >>matching harness for the World's first weather satellite, TIROS 1, which was >>launched April 1, 1960. >> > >Walt, >Could you please tell me a little more about that satellite? Reason I >ask is there is a place I am sure you can enlighten us on, called Camp >Evans. >I know there is still a big dish antenna there, although the wooden >structure surrounding it is failing. Supposedly it was used for >communicating with Tiros. Is that right? > >A NJ radio club had a hamfest there in April, and I was able to walk >under the antenna and they have some displays there. Supposedly Camp >Evans was also the place where the first signals were bounced off the >moon, somewhere around 1946. >Camp Evans looks like at least parts of it are being renovated. >Brookdale Comm. College has some classrooms there, very modern. >Oh yes, and on the road leading to Camp Evans (Marconi Road !!) there >is a display of the top portion of one of Marconi's towers, and a >plaque noting that there were many such towers in the area in the >early 1900s. >Quite a bit of radio history, in these parts of New Jersey, and I am >glad to know one of the pioneers frequents this newsgroup. >Not far away, in Holmdel, is where AT&T communicated with Telstar, I >believe, about the same time period. The Holmdel facility, home to >6000 Bell Labs employees as recently as1999 has been sold and is going >to be demolished. > >Rick K2XT Hi Rick, Thanks for the response to my post. The first eight versions of TIROS were shaped as a short 18-sided cylinder about 30 inches in diameter and about two feet tall. It contained a 1/2 inch vidicon video camera and an infra red (IR) sensor. Direct viewing of both the camera and IR sensor was attained whenever the spacecraft was within sighting distance of the three ground stations, one at Ft. Monmouth, NJ, one at our RCA Space Center at Hightstown, NJ, (where we built the spacecraft) which I operated, and one in Australia. There were also two tape recorders that recorded the video and IR when over other places on Earth out of range of the ground stations, for playback when in range. The video and IR transmitters each delivered 5 watts, the video on 235 MHz and the IR on 237.8 MHz. There were two beacon and telemetry transmitters, one on 108 MHz and the other on 108.03 MHz, each delivering 30 milliwatts. Beginning with TIROS 3 and on through 8, the beacon-telemetry transmitter frequencies were changed to 136.0 and 136.5 MHz, leaving the 108 MHz frequencies free for aircraft communications. The monopole antennas were sleeve type. A half-inch sleeve 1/4 wl long at 236 MHz radiated the video and IR signals, and a rod extension, along with the sleeve, radiated the 108 MHz signals. The internal portion of the sleeve formed a quarter-wave shorted transmission line that decoupled the rod extension at the 235 and 237.8 MHz frequencies, as part of the frequency-separation circuitry that allowed the antenna to operate on the two frequency bands separated by approximately an octave. I have a number of pictures of the spacecraft in various views in JPG format that I'll send to you as soon as I can get them together. Now concering Camp Evans, I'm not sure that that was the location of the TIROS dish, which was 28 feet in diameter. All I can recall after all these years is that the dish was at Ft. Monmouth, the location of USASRDL, the Signal Corps Development Laboratory. Camp Evans might have been on the Ft. Monmouth Army Base, but I just can't remember. I knew several of the engineering guys at Bell Labs Holmdel, but all I knew there have passed on. Hope this helps, Walt, W2DU Article: 227595 of rec.radio.amateur.antenna From: Jerseyj Subject: Re: VENT Re: (OT) : Democrat's Out-Sourcing "Hate America" To Canada ! References: <129m9ijcnshm47f@corp.supernews.com> <129ofcclvejs22f@corp.supernews.com> <0bjo92p0h2dfqcum243lc3u1mqv49nu10h@4ax.com> <1152720850.662591.37690@b28g2000cwb.googlegroups.com> <1152839909.231750.229790@35g2000cwc.googlegroups.com> <1152848674.361536.176700@h48g2000cwc.googlegroups.com> Date: Wed, 02 Aug 2006 18:42:05 -0400 Message-ID: In article , Paul Hinman wrote: > J. D. B. wrote: > > > Well at least your estate will get to keep your life savings. If you > > get sick late in the year, and the healthcare facility/hospital shut > > down for the rest of the year because it ran out of government money > > (a typical scenario in Canada), there will be no one to give you any > > care and you'll just die. But hey, your life savings will still be > > intact! Is socialized health care great or what? > > > >> > >> - At least in Canada you get to keep > >> - your life savings if you get sick. > >> > I am a Canadian with serious chronic health problems and I have much > more experience with the health system than I would like to have, I > have come close being a silent key several times, I am sure that there > are some who feel that is too bad that I was allowed to breed before my > medical problems became obvious. In the minds of some I suppose that I > have peed in the genetic pool. > > I have never heard of a Canadian hospital shutting down because the > money did not last until fiscal year end. While there are some > weaknesses in our system such as delays in elective procedures but when > the sand was running out of the hour glass there was always a system to > help me out. Here everyone can get insured, there is an option to opt > out of medicare but who would? > > Think of the overhead that American doctors face having to deal with > multiple insurance companies, each with different forms and procedures. > Think of the people who can't get medical insurance no matter what the > cost. Think of those who don't have because they can't afford it. And > then there are those who exercise their right not have it. > > In a situation where people get treated but can't afford to pay, the > rates for everyone else must go up to compensate. > > Canada is not perfect but it is a pretty nice place to live and we try > to contribute as best we can. > > By the way, if I were an American I would vote republican but I am not a > single issue voter so don't construe that to mean that I from the far > right wing. Consider me a fiscal conservative with a social conscience. Interestingly, my wife is also a Canadian, she moved down here to the US just before we got married. She worked only part time in Canada. Aparantly, the health care is NOT universal, as many meds she needed she had to pay for out of her own pocket, and had to wait months for an MRI (She just had one here on one weeks notice). Yup, there are issues here too, but the Canadian system is far from perfect either. Article: 227596 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Magloop capacitor padding? Message-ID: References: Date: Wed, 02 Aug 2006 22:49:51 GMT On Wed, 02 Aug 2006 22:09:43 GMT, "Lee" wrote: >Hi!.... > >I`ve just built a magloop 5`square and i find the variable cap only tunes >down to 4.45mhz.. >can i pad the cap out with a coaxial ur213 stub to reach 3.5mhz ???.... > >Lee.......G6ZSG..... > >(The 1metre loop works fine - 15 to 7mhz ).. :-) > This is a riddle, right? If you are after a few pF, then the losses in the stub will be very low, but at lower reactances, the resistance or loss element becomes more significant. So you have hinted a bit at this loop.... lets do some guessing: An inductor of 1.5m square and 20mm conductor diameter has an inductance around 5uH, thats about 140 ohms at 4.45MHz... so it looks like your tuning capacitor is 250pF. You probably need around 400pF at 3.5MHz, so lets add another 200pF in shunt from an RG213 o/c stub. You need an admittance of ????+j0.0044 S. Using the line loss calculator at http://www.vk1od.net/tl/tllce.php , it looks like 1.95m of RG213 terminated with 1e8+j0 will have an input admittance of 0.000004+j0.004401. So this stub is dropping around 4e-6S of loss conductance across the loop, or 250kOhms in shunt if you like. This shunt resistance is somewhat lower than you would expect with a good quality capacitor. You can estimate the effect by plugging the 250KOhms resistance into your design model and examining the change in efficiency. Owen -- Article: 227597 of rec.radio.amateur.antenna From: "Reg Edwards" References: Subject: Re: Magloop capacitor padding? Date: Wed, 2 Aug 2006 23:58:35 +0100 Message-ID: "Lee" wrote in message news:Ho9Ag.45055$9d4.14908@fe2.news.blueyonder.co.uk... > Hi!.... > > I`ve just built a magloop 5`square and i find the variable cap only tunes > down to 4.45mhz.. > can i pad the cap out with a coaxial ur213 stub to reach 3.5mhz ???.... > > Lee.......G6ZSG..... > > (The 1metre loop works fine - 15 to 7mhz ).. :-) > ===================================== Lee, You will need at least 70 percent more capacitance. But where you'll find that much, high voltage, high Q capacitance is anybody's guess. You would do better to fit a larger variable capacitor designed for the job. Or make a larger loop. A lumped capacitor made from coax cable is low Q anyway because of the small diameter of the inner conductor. Compare coax inner conductor diameter with loop conductor diameter. ---- Download program MAGLOOP4 from website below to give you some ideas. ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 227598 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> Message-ID: Date: Wed, 02 Aug 2006 23:12:41 GMT Tom Donaly wrote: >> 2 liter pop bottles are in abundance in the US. If a coil >> form is used for a coax choke, that's the most likely. > > But then you have to drink 2 liters of wet, sticky, gooey, sickeningly > sweet, soda pop. Lipton and Nestea tea also come in those bottles as does lots of sugar free diet stuff. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227599 of rec.radio.amateur.antenna From: Paul Hinman Subject: Re: VENT Re: (OT) : Democrat's Out-Sourcing "Hate America" To Canada References: <129m9ijcnshm47f@corp.supernews.com> <129ofcclvejs22f@corp.supernews.com> <0bjo92p0h2dfqcum243lc3u1mqv49nu10h@4ax.com> <1152720850.662591.37690@b28g2000cwb.googlegroups.com> <1152839909.231750.229790@35g2000cwc.googlegroups.com> <1152848674.361536.176700@h48g2000cwc.googlegroups.com> Message-ID: Date: Wed, 02 Aug 2006 23:15:03 GMT This is a multi-part message in MIME format. --------------070301060301010202060005 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Jerseyj wrote: >In article , > Paul Hinman wrote: > > > >>J. D. B. wrote: >> >> >> >>>Well at least your estate will get to keep your life savings. If you >>>get sick late in the year, and the healthcare facility/hospital shut >>>down for the rest of the year because it ran out of government money >>>(a typical scenario in Canada), there will be no one to give you any >>>care and you'll just die. But hey, your life savings will still be >>>intact! Is socialized health care great or what? >>> >>> >>> >>>>- At least in Canada you get to keep >>>>- your life savings if you get sick. >>>> >>>> >>>> >>I am a Canadian with serious chronic health problems and I have much >>more experience with the health system than I would like to have, I >>have come close being a silent key several times, I am sure that there >>are some who feel that is too bad that I was allowed to breed before my >>medical problems became obvious. In the minds of some I suppose that I >>have peed in the genetic pool. >> >>I have never heard of a Canadian hospital shutting down because the >>money did not last until fiscal year end. While there are some >>weaknesses in our system such as delays in elective procedures but when >>the sand was running out of the hour glass there was always a system to >>help me out. Here everyone can get insured, there is an option to opt >>out of medicare but who would? >> >>Think of the overhead that American doctors face having to deal with >>multiple insurance companies, each with different forms and procedures. >>Think of the people who can't get medical insurance no matter what the >>cost. Think of those who don't have because they can't afford it. And >>then there are those who exercise their right not have it. >> >>In a situation where people get treated but can't afford to pay, the >>rates for everyone else must go up to compensate. >> >>Canada is not perfect but it is a pretty nice place to live and we try >>to contribute as best we can. >> >>By the way, if I were an American I would vote republican but I am not a >>single issue voter so don't construe that to mean that I from the far >>right wing. Consider me a fiscal conservative with a social conscience. >> >> > >Interestingly, my wife is also a Canadian, she moved down here to the US >just before we got married. She worked only part time in Canada. >Aparantly, the health care is NOT universal, as many meds she needed she >had to pay for out of her own pocket, and had to wait months for an MRI >(She just had one here on one weeks notice). Yup, there are issues here >too, but the Canadian system is far from perfect either. > > There are delays I will admit that. Universal means that everyone can participate it, it does not mean that it covers everything. I also have private insurance to cover drugs, dentistry, the surcharge for private hosptital rooms etc. I guess that I got really ticked off when the guy said that hospitals routinely close because they run out of money, that was bull and it really ticked me off. Please excuse my sensitivity. Paul -- Paul S. Hinman - VE6LDS long West 113 deg 27 min 20 sec lat North 53 deg 27 min 3 sec Maidenhead Locator DO33gk --------------070301060301010202060005 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Jerseyj wrote:
In article <TY1Ag.303358$iF6.152609@pd7tw2no>,
 Paul Hinman <paul.hinman@shaw.ca> wrote:

  
J. D. B. wrote:

    
Well at least your estate will get to keep your life savings. If you 
get sick late in the year, and the healthcare facility/hospital shut 
down for the rest of the year because it ran out of government money 
(a typical scenario in Canada), there will be no one to give you any 
care and you'll just die.  But hey, your life savings will still be 
intact! Is socialized health care great or what?

      
- At least in Canada you get to keep
- your life savings if you get sick.

        
I am a Canadian with serious chronic health problems and I have much 
more experience with the health system than I would like to have,  I 
have come close being a silent key several times, I am sure that there 
are some who feel that is too bad that I was allowed to breed before my 
medical problems became obvious.  In the minds of some I suppose that I 
have peed in the genetic pool. 

I have never heard of a Canadian hospital shutting down because the 
money did not last until fiscal year end.  While there are some 
weaknesses in our system such as delays in elective procedures but when 
the sand was running out of the hour glass there was always a system to 
help me out.  Here everyone can get insured, there is an option to opt 
out of medicare but who would?

Think of the overhead that American doctors face having to deal with 
multiple insurance companies, each with different forms and procedures.  
Think of the people who can't get medical insurance no matter what the 
cost.  Think of those who don't have because they can't afford it.  And 
then there are those who exercise their right not have it.

In a situation where people get treated but can't afford to pay, the 
rates for everyone else must go up to compensate.

Canada is not perfect but it is a pretty nice place to live and we try 
to contribute as best we can.

By the way, if I were an American I would vote republican but I am not a 
single issue voter so don't construe that to mean that I from the far 
right wing.  Consider me a fiscal conservative with a social conscience.
    

Interestingly, my wife is also a Canadian, she moved down here to the US 
just before we got married. She worked only part time in Canada. 
Aparantly, the health care is NOT universal, as many meds she needed she 
had to pay for out of her own pocket, and had to wait months for an MRI 
(She just had one here on one weeks notice). Yup, there are issues here 
too, but the Canadian system is far from perfect either.
  
There are delays I will admit that.  Universal means that everyone can participate it, it does not mean that it covers everything.  I also have private insurance to cover drugs, dentistry,  the surcharge for private hosptital rooms etc.  I guess that I got really ticked off when the guy said that hospitals routinely close because they run out of money, that was bull and it really ticked me off.  Please excuse my sensitivity.

Paul

-- 
Paul S. Hinman - VE6LDS
long West 113 deg 27 min 20 sec
lat  North 53 deg 27 min 3 sec
Maidenhead Locator DO33gk 

--------------070301060301010202060005-- Article: 227600 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Wed, 02 Aug 2006 23:17:12 GMT Reg Edwards wrote: > But Cecil, maximum resistance, maximum reactance and maximum impedance > all occur at the same resonant frequency. Reg, if you would learn the Smith Chart, you would know that is not true. :-) At self-resonance, the inductive reactance cancels the capacitive reactance leaving a pure resistance usually of a few thousand ohms. But I agree with you that a purely resistive self-resonant choke is not a bad thing. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227601 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Date: Thu, 3 Aug 2006 01:11:36 +0100 Message-ID: "Cecil Moore" wrote in message news:YnaAg.1890$kO3.908@newssvr12.news.prodigy.com... > Reg Edwards wrote: > > But Cecil, maximum resistance, maximum reactance and maximum impedance > > all occur at the same resonant frequency. > > Reg, if you would learn the Smith Chart, you would know > that is not true. :-) At self-resonance, the inductive > reactance cancels the capacitive reactance leaving a > pure resistance usually of a few thousand ohms. But I > agree with you that a purely resistive self-resonant > choke is not a bad thing. > -- > 73, Cecil http://www.qsl.net/w5dxp ====================================== Cec, I don't need a Smith Chart, and neither does anybody else, to work out the resistance at resonance. I don't think you quite know what you are doing with elementary circuit analysis. The Smith Chart is giving you the wrong answer. The resistance of a choke at HF at self resonance is in the order of a megohm or more, not just a few thousand ohms. By the way, what is the diameter and winding length of a USA pop bottle. ---- Reg. Article: 227602 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> Subject: Re: Radiating Efficiency Date: Thu, 3 Aug 2006 02:00:19 +0100 Message-ID: Hasan, Why don't you look for differences between BLE and NEC4? I'm sure you'll find some. ---- Reg. Article: 227603 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Thu, 03 Aug 2006 01:24:28 GMT Reg Edwards wrote: > The > resistance of a choke at HF at self resonance is in the order of a > megohm or more, not just a few thousand ohms. I just guessed at it, Reg, based on my measurements of toroidal chokes and W2DU baluns. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227604 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Thu, 03 Aug 2006 01:27:40 GMT Reg Edwards wrote: > By the way, what is the diameter and winding length of a USA pop > bottle. The diameter of a 2 liter bottle is 4 inches. The Bible says the ratio of circumference to diameter of a circle is 3. :-) The length of the bottle is about a foot. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227605 of rec.radio.amateur.antenna From: "Lee" References: Subject: Re: Magloop capacitor padding? Message-ID: <9lcAg.39529$F8.1099@fe3.news.blueyonder.co.uk> Date: Thu, 03 Aug 2006 01:30:45 GMT "Owen Duffy" wrote in message news:go92d2ljek3b8guf0nmb9illkvejnr25d6@4ax.com... > On Wed, 02 Aug 2006 22:09:43 GMT, "Lee" > wrote: > > >Hi!.... > > > >I`ve just built a magloop 5`square and i find the variable cap only tunes > >down to 4.45mhz.. > >can i pad the cap out with a coaxial ur213 stub to reach 3.5mhz ???.... > > > >Lee.......G6ZSG..... > > > >(The 1metre loop works fine - 15 to 7mhz ).. :-) > > > > This is a riddle, right? > > If you are after a few pF, then the losses in the stub will be very > low, but at lower reactances, the resistance or loss element becomes > more significant. > > So you have hinted a bit at this loop.... lets do some guessing: > > An inductor of 1.5m square and 20mm conductor diameter has an > inductance around 5uH, thats about 140 ohms at 4.45MHz... so it looks > like your tuning capacitor is 250pF. > > You probably need around 400pF at 3.5MHz, so lets add another 200pF in > shunt from an RG213 o/c stub. You need an admittance of ????+j0.0044 > S. > > Using the line loss calculator at http://www.vk1od.net/tl/tllce.php , > it looks like 1.95m of RG213 terminated with 1e8+j0 will have an input > admittance of 0.000004+j0.004401. So this stub is dropping around > 4e-6S of loss conductance across the loop, or 250kOhms in shunt if you > like. This shunt resistance is somewhat lower than you would expect > with a good quality capacitor. > > You can estimate the effect by plugging the 250KOhms resistance into > your design model and examining the change in efficiency. > > Owen > -- Heh!....too technical for me i`m afraid Owen....Heh heh..... :-) I`m using a tuned RG213 stub about 2meters long as a temporary measure for 80, till i can sort the cap problem....... i just need a simple answer is all....... Thanks..... Lee.........G6ZSG...... Article: 227606 of rec.radio.amateur.antenna From: "Frank's" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> Subject: Re: Radiating Efficiency Message-ID: <1ucAg.136902$A8.3454@clgrps12> Date: Thu, 03 Aug 2006 01:40:13 GMT > Frank, > > Thank you for the above. > > Can you do 36 radials from 0.6 to 8.0 metres in increments of 0.2 > metres? > > Must be the same input data as before :- F = 8.07 MHz, Ground = > 150,16 Radial diameter = 1.64mm, Depth = 25mm. Reg, Here are the results from the analysis of a 26 radial system. All dimensions and parameters are the same as for the single radial antenna as you defined above: 0.6 m -- Radial Z = 37.3 - j 28.1 -- Efficiency 15% 0.8 m -- Radial Z = 30.5 - j 21.0 1.0 m -- Radial Z = 26.2 - j 16.9 1.2 m -- Radial Z = 23.2 - j 14.2 1.4 m -- Radial Z = 20.9 - j 12.4 1.6 m -- Radial Z = 19.1 - j 11.1 1.8 m -- Radial Z = 17.6 - j 10.1 -- Efficiency 21.0% 2.0 m -- Radial Z = 16.2 - j 9.4 2.2 m -- Radial Z = 15.1 - j 8.8 2.4 m -- Radial Z = 14.0 - j 8.4 2.6 m -- Radial Z = 13.0 - j 8.0 2.8 m -- Radial Z = 12.1 - j 7.7 3.0 m -- Radial Z = 11.3 - j 7.4 3.2 m -- Radial Z = 10.4 - j 7.1 -- Efficiency 24.5% 3.4 m -- Radial Z = 9.7 - j 6.8 3.6 m -- Radial Z = 8.9 - j 6.5 3.8 m -- Radial Z = 8.2 - j 6.2 4.0 m -- Radial Z = 7.5 - j 5.8 4.2 m -- Radial Z = 6.9 - j 5.5 4.4 m -- Radial Z = 6.4 - j 5.1 4.6 m -- Radial Z = 5.8 - j 4.7 4.8 m -- Radial Z = 5.4 - j 4.3 5.0 m -- Radial Z = 5.0 - j 3.9 -- Efficiency 27.8% 5.2 m -- Radial Z = 4.6 - j 3.5 5.4 m -- Radial Z = 4.3 - j 3.1 5.6 m -- Radial Z = 4.0 - j 2.7 5.8 m -- Radial Z = 3.7 - j 2.3 6.0 m -- Radial Z = 3.5 - j 2.0 6.2 m -- Radial Z = 3.3 - j 1.6 6.4 m -- Radial Z = 3.1 - j 1.3 6.6 m -- Radial Z = 3.0 - j 0.9 6.8 m -- Radial Z = 2.9 - j 0.6 7.0 m -- Radial Z = 2.8 - j 0.3 7.2 m -- Radial Z = 2.7 + j 0.01 7.4 m -- Radial Z = 2.6 + j 0.3 7.6 m -- Radial Z = 2.6 + j 0.6 7.8 m -- Radial Z = 2.6 + j 0.9 8.0 m -- Radial Z = 2.5 + j 1.1 -- Efficiency 31.1% . . 10.0 m -- Radial Z = 3.0 + j 3.3 -- Efficiency 32.6% Where I have shown the efficiency as sky wave power out. The input impedance is that of all radials, so for a single radial the input Zr must be Ztr * 26. Frank Article: 227607 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Magloop capacitor padding? Message-ID: <2bl2d25ingi88ch2k7pnkleke1vpd2emtc@4ax.com> References: <9lcAg.39529$F8.1099@fe3.news.blueyonder.co.uk> Date: Thu, 03 Aug 2006 01:54:11 GMT On Thu, 03 Aug 2006 01:30:45 GMT, "Lee" wrote: >Heh!....too technical for me i`m afraid Owen....Heh heh..... :-) > >I`m using a tuned RG213 stub about 2meters long as a temporary measure for >80, till i can sort the cap problem....... i just need a simple answer is >all....... > Well, my guess from you data is you will need about 2m of RG213, and you will find that it "works", but it doesn't work as well as a low loss capacitor. Owen -- Article: 227608 of rec.radio.amateur.antenna From: "Lee" References: Subject: Re: Magloop capacitor padding? Message-ID: <5FcAg.39586$F8.12668@fe3.news.blueyonder.co.uk> Date: Thu, 03 Aug 2006 01:52:01 GMT "Reg Edwards" wrote in message news:UPadnYVVDbHKs0zZRVnyjQ@bt.com... > > "Lee" wrote in message > news:Ho9Ag.45055$9d4.14908@fe2.news.blueyonder.co.uk... > > Hi!.... > > > > I`ve just built a magloop 5`square and i find the variable cap only > tunes > > down to 4.45mhz.. > > can i pad the cap out with a coaxial ur213 stub to reach 3.5mhz > ???.... > > > > Lee.......G6ZSG..... > > (The 1metre loop works fine - 15 to 7mhz ).. < < Sorry, should read 15 to 40 meters..... :-/ > ===================================== > Lee, > > You will need at least 70 percent more capacitance. > > But where you'll find that much, high voltage, high Q capacitance is > anybody's guess. You would do better to fit a larger variable > capacitor designed for the job. Or make a larger loop. My thoughts also on both likely answers Reg but the cap is a foot long 4 inch sq 12/14kv 26 rotary vanes, now 28 as i`ve added (squeezed) two more rotaty vanes and four stators into the frame (came in kit form), also designed the loop using loopcalc program which gives 407pf at 3.5megs...my cap is supposed to be 500pf !!...... > A lumped capacitor made from coax cable is low Q anyway because of the > small diameter of the inner conductor. Compare coax inner conductor > diameter with loop conductor diameter. > ---- > Download program MAGLOOP4 from website below to give you some ideas. Got it, good prog...... Thanks Reg... Lee........G6ZSG...... > ........................................................... > Regards from Reg, G4FGQ > For Free Radio Design Software go to > http://www.btinternet.com/~g4fgq.regp > ........................................................... > > Article: 227609 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: Any info on this type of mobile antenna? Date: Wed, 02 Aug 2006 18:55:56 -0700 Message-ID: References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> ORIGINAL MESSAGE: On Wed, 02 Aug 2006 22:18:18 GMT, "Jerry Martes" wrote: >It might be one of those >mobile lawnchairs that the Israelis are trying to eliminate from Lebanon. ------------ REPLY SEPARATOR ------------ A new Lebanese commuter car? Bill, W6WRT Article: 227610 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Wed, 02 Aug 2006 18:57:33 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> ORIGINAL MESSAGE: On Wed, 2 Aug 2006 14:04:30 -0700, "Bob Agnew" wrote: >Do you know of any place in Southern California that doesn't have such >restrictions? ------------ REPLY SEPARATOR ------------ Yep. I live 30 miles due north of Palm Springs and the jackrabbits don't care at all. Bill, W6WRT Article: 227611 of rec.radio.amateur.antenna From: "Lee" References: <9lcAg.39529$F8.1099@fe3.news.blueyonder.co.uk> <2bl2d25ingi88ch2k7pnkleke1vpd2emtc@4ax.com> Subject: Re: Magloop capacitor padding? Message-ID: Date: Thu, 03 Aug 2006 02:08:36 GMT "Owen Duffy" wrote in message news:2bl2d25ingi88ch2k7pnkleke1vpd2emtc@4ax.com... > On Thu, 03 Aug 2006 01:30:45 GMT, "Lee" > wrote: > > >Heh!....too technical for me i`m afraid Owen....Heh heh..... :-) > > > >I`m using a tuned RG213 stub about 2meters long as a temporary measure for > >80, till i can sort the cap problem....... i just need a simple answer is > >all....... > > > > Well, my guess from you data is you will need about 2m of RG213, and > you will find that it "works", but it doesn't work as well as a low > loss capacitor. True, but it works......altho` it`s very narrow band, would much prefer a variable cap` or even a vacuum cap would be better still....can`t afford one tho`......ho-hum...... Thanks Owen.... Lee.......G6ZSG..... Article: 227612 of rec.radio.amateur.antenna From: hot-ham-and-cheese@hotmail.com Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 2 Aug 2006 19:32:08 -0700 Message-ID: <1154572328.292003.53650@b28g2000cwb.googlegroups.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> Cecil Moore wrote: > hot-ham-and-cheese@hotmail.com wrote: > > The requirements for an amateur radio license have been all over the > > map over the history of the service. The ORIGINAL amateur radio > > license had no Morse Code Exam, even when Morse Code was the only means > > of communicating. > > Therein lies the solution to the problem. Make A1 the > only mode allowed within amateur radio - solves all > the problems, doesn't it? No more mode arguments, no > more band crowding, no more expensive equipment, ... > The list of advantages is virtually endless. OK, fair enough. The Amateur Radio Service of the 21st century will be all CW without a Morse Code Exam. We'll go out of existance EXACTLY like we came in. I'm sure that will make the Morseodists happy. Article: 227613 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Date: Thu, 3 Aug 2006 03:37:05 +0100 Message-ID: > The diameter of a 2 liter bottle is 4 inches. The Bible > says the ratio of circumference to diameter of a circle > is 3. :-) The length of the bottle is about a foot. > -- > 73, Cecil http://www.qsl.net/w5dxp ============================================ Before publishing your rules of thumb you can check your reasoning by using program SELFRES3. Download from website below. I must admit, rules of thumb are quite adequate for coaxial chokes. Almost anything will work. Very often things will work quite well without a choke at all. ;o) ----- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 227614 of rec.radio.amateur.antenna From: Owen Duffy Subject: Re: Rule of Thumb for coax chokes Message-ID: References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Date: Thu, 03 Aug 2006 03:08:15 GMT On Thu, 3 Aug 2006 03:37:05 +0100, "Reg Edwards" wrote: >I must admit, rules of thumb are quite adequate for coaxial chokes. >Almost anything will work. Very often things will work quite well >without a choke at all. ;o) But the Rule Of Thumb to avoid (presumably) parallel resonance of the choke for the reasons given is ROT. Owen -- Article: 227615 of rec.radio.amateur.antenna From: hot-ham-and-cheese@hotmail.com Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 2 Aug 2006 20:05:21 -0700 Message-ID: <1154574315.819259.204140@b28g2000cwb.googlegroups.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> Al Klein wrote: > On 23 Jul 2006 07:26:05 -0700, hot-ham-and-cheese@hotmail.com wrote: > > >Al Klein wrote: > > >> By taking the test you're claiming that you understand the questions > >> and know the answers. > > >By releasing the Question Pools, the FCC is claiming that you must > >memorize the answers. > > Must? Where's the "must"? Or do you mean "If you aren't intelligent > enough, or motivated enough, to learn a little, the only way to get a > license is to memorize the answers." No, not all all. It should be obvious that if you can make a ridiculous statement such as the one you made above, I can make a ridiculous statement also. > >No one is claiming any such thing. I guess you missed this part which is key to you're not understanding that my statement was ridiculous. > >> By memorizing the answers you're not learning > >> enough to understand the questions. > > >> But I wouldn't expect you to understand what "honesty" means. > > >Why not? > > Because he's already admitted that he's dishonest. When will you admit that you are dishonest? > >> >how balanced is to to place CW over all over ham knowledge? > > >> No one is, any more than by requiring people to know the law one is > >> putting the law "over all ham knowledge". > > >CW is pass/fail. To fail CW denies all HF privs (except for Alaska). > > Theory is also pass/fail. To fail to get the required number of > correct answers denies all privs - HF, VHF, UHF ... There is no pass/fail practical for SSB, FM, AM, FSTV, SSTV, RTTY, FAX, Packet, PSK, etc, etc, etc. > >> >How progressive is it? > > >> How progressive is it to not require people to know ... oh, yeah, > >> that's progressive, since the new thing is to hand out licenses > >> because people have some kind of "right" to get on the air. > > >Then why is it with the prospect of losing the CW Exam, that you'se > >guys want to "beef up" the written exams? > > We don't. That is not true. > We want to get back the level it used to be before it was > dumbed down to the point that you could almost pass it if you never > heard of the FCC, ham radio or electronics. You're referring to the Conditional license, right? > Just by guessing at the > answers. It used to require that you draw (was it 3?) schematics. You tell me? Was it 2 or was it 3? Is this your lucky day? > From scratch. Let's see how many people could do that today. A > Colpitts oscillator, a Hartley oscillator and some other circuit that > I've forgotten at the moment. You should self-modify your license and cease amateur operation until you remember. The amateur is self-policing, and you no longer meet your own standard. > They're still as relevant today as they > were 50 years ago. Other things are relevant today that weren't even known 50 years ago. > >> >how loyal is it to denny the nation the benifits of allowing more > >> >operators > > >> What "benefits" does the country get from more people using radios who > >> don't know the first thing about them? (Whatever "denny" means.) > > >It's always been that way. You could even buy Heathkits already > >assembled. > > But you had to actually *know* a little theory to use one legally. No you didn't. > Today all you need is the time to take the test and the money for the > test and the equipment. IOW, a CB "license" with a tiny bit of > annoyance up front. How does CB benefit the country? Sounds like you need to look for a different hobby if you have such disdain for your fellow amateurs. Best of Luck. > >> You don't acquire knowledge (which is what's needed) by playing with a > >> radio. > > >Then the military has wasted billions of dollars over the years > >"training" radio operators. > > I trained operators when I was in the military. We didn't do it by > giving recruits radios and telling them to go jam each other. I used radios in the military. I never used a CW key in the military. I never jammed another operator, although Brandywine asked me to reduce power once. > >> >how patriotic is it to keep a staion forom aquiing the skill to be > >> >ready for service to conutry and community? > > >> How does playing CB on the ham bands give one "the skill to be > >> ready for service to conutry and community"? > > >Who knows? That's not what Mark is talking about, is it? > > That's exactly what he's talking about. Give someone a radio and a > "license" to use it and he'll "acquire the skill to be ready for > service to country and community". That's what Mark said, right up > above. How does one acquire skill by playing radio? We self-train. It is a continuous process of improvements. You mistakenly believe that at the conclusion of The Exam, the "operator" is 100%. Never was, Never will be, and neither were you weren't. I'm beginning to think that you're from the school of "The Older I Get, The Better I Was!" > >> Or any skill, other than > >> getting what you want? You don't acquire skill by doing something > >> that requires no skill. > > >So it really is all about CW. Why have a written Exam at all? > > You don't acquire technical skill by doing something that doesn't > require technical skill. You don't acquire operating skill by doing > something that requires no operating skill. And you don't acquire > skill in CW by cursing into a mike. Nor do you. > But that's what Mark and his ilk want - we'll have "skilled operators" > if we allow people to buy radios and put them on the air with no skill > or knowledge. By osmosis? Or by magic? I've listened to emergency responders on a scanner before. They don't use Morse Code, they don't use CW. They use FM/Voice. Somehow they are effective at it, not having taken a Morse Code test. How can this be? Tell you what. The next time your YL dials 911 for you, she has to communicate with the 911 Operator in Morse Code. She can just sound it out with her mouth, no keyer, sounder, clacker or anything else required. When the Operator tells her to speak normally, your YL is allowed to say once, and only once, using her normal voice, "Real communications takes place with Morse Code" and then revert back to sounding out her message with Morse Code dits and dahs. Agreed? On your block of granite, she will say, "Here Lays Al Klein, Who had no use for Voice Modes. May He Rest In Peace" > >> And you, particularly, don't acquire > >> knowledge by demanding something for nothing. > > >The requirements for an amateur radio license have been all over the > >map over the history of the service. The ORIGINAL amateur radio > >license had no Morse Code Exam, even when Morse Code was the only means > >of communicating. > > So you'd get a license not knowing CW, build a radio (you couldn't buy > one then) and ... what? Sit and look at it. Some things are just too > obvious to need mentioning. Please diagram that radio from "Scratch." > >Get over it. Everyone else is moving on. > > Evidently not, or I'd be the only one in the world advocating that a > test should actually test for something. There are actually millions > of us who don't think lack of instant gratification is the worst thing > in the world. Dial 911 and tell the operator that you don't need instant gratification, take your time. > What next? DXCC awards for those who *want* to work 100 countries? You seem to be confused. DXCC is an award offered by the ARRL, not the FCC. It has nothing to do with licensing. You ask "What next?" How about a test for everyone else except you, where you get to try to recall what was on your test, but can't. Article: 227616 of rec.radio.amateur.antenna Date: Wed, 02 Aug 2006 23:07:41 -0400 From: Mike Coslo Subject: Re: neighborhood antenna restrictions References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Message-ID: <99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com> Bob Agnew wrote: > Do you know of any place in Southern California that doesn't have such > restrictions? > Same difference. I wouldn't live in one of those deed restricted developments, and I definitely wouldn't live in SoCa. We have choices. - 73 de Mike KB3EIA - Article: 227617 of rec.radio.amateur.antenna From: hot-ham-and-cheese@hotmail.com Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 2 Aug 2006 20:15:58 -0700 Message-ID: <1154574958.502274.257100@75g2000cwc.googlegroups.com> References: <30954.oidi09.d0904.ddoi0@qkd.org> Al Klein wrote: > On Sat, 22 Jul 2006 20:14:17 GMT, Slow Code wrote: > > >The fit get a ham license. All the rest get cell phones, CB, and shortwave > >listening. > > No, SC - in today's society we can't hurt people's feelings, so the > loud get anything they want. Al, you're getting louder. SC has been loud for a long time. Article: 227618 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 2 Aug 2006 20:27:49 -0700 Message-ID: <1154575669.483390.122580@h48g2000cwc.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Antonio, My intuition about the rod and wire in parallel appears to be incorrect unless the resistance of the rod is quite low, at least on 7MHz. My EZNEC model shows that the wires in parallel give substantial loss (up to a couple of dB or so lost in the resistance of the rod) with the wire connected at the top and bottom and the total rod resistance in the 1-10 ohm range. Separated and insulated from the rod seems to work quite well on 7MHz. However, if the rod is connected directly to the ground radials a large amount of loss is introduced. (I got 5dB in some cases with fairly high resistance) I have found other frequencies where the loss is more than a dB or so even in this configuration (18MHz is near a halfwave resonance, which is problematic, as Reg has correctly surmised). The model shows that the current distribution on the lossy element is occasionally complicated and bears further investigation. I've posted the model I put together online. It's in some random configuration of frequency, load resistance, and connectedness of the lossy rod to ground, I don't know where it was when I saved it: http://www.n3ox.net/projects/eznec/carbonpole.ez It has too many segments for the free version but it probably bears more investigation ... it is possible for the setup to be quite lossy on some frequencies. I think Reg's comment about halfwave resonance and intermediate resistances between very low and very high was quite accurate, as was mine about quarterwave resonance and connection to the groundplane. 73, Dan Article: 227619 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> Subject: Re: Question on carbon fibre fishing rod Message-ID: Date: Wed, 2 Aug 2006 20:28:13 -0700 wrote in message news:1154555654.618018.192280@i42g2000cwa.googlegroups.com... > Or if it is 1/4-wave resonant and is in relatively low-resistance > contact with the groundplane. > > Dan > > But loss will be induced in the rod only when the rod is near to > > 1/2-wave resonant. > > ---- > > Reg. > Tony, what happens if you load the transmitter into the rod, directly? Upon reading that the end-to-end resistance of the pole may be about an ohm, that idea was in my head instantly. Impedance to RF is a different animal, of course but I would try it on low power, just to measure SWR. And you don't have to do anything, really, to determine whether you can _hear_ using it! I hope you keep us informed. 73, "Sal" (really KD6VKW) Article: 227620 of rec.radio.amateur.antenna From: "Sal M. Onella" References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Subject: Re: neighborhood antenna restrictions Message-ID: <4ieAg.12679$lv.4300@fed1read12> Date: Wed, 2 Aug 2006 20:44:00 -0700 "Cecil Moore" wrote in message news:NA8Ag.526$%j7.393@newssvr29.news.prodigy.net... > Bob Agnew wrote: > > Do you know of any place in Southern California that doesn't have such > > restrictions? > > One probably has to move away from the left coast. :-) > -- > 73, Cecil http://www.qsl.net/w5dxp Not actually. On a clear day, I can see the Pacific Ocean from my yard and we have no HOA and no antenna restrictions in the CC&R's. My area was developed in 1968 and the CC&R's are up for renewal in a few years. I need to pay attention to that event. I might lose the right to put up more antennas and be "grandfathered" for only what I have now. Article: 227621 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Wed, 02 Aug 2006 20:57:30 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com> ORIGINAL MESSAGE: On Wed, 02 Aug 2006 23:07:41 -0400, Mike Coslo wrote: >and I definitely wouldn't live in SoCa. ------------ REPLY SEPARATOR ------------ The only thing we need to make you feel right at home would be humidity, ice storms and snow. We're working on it. I'll get back to you. Bill, W6WRT looking for his snowshoes Article: 227622 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> Subject: Re: Radiating Efficiency Date: Thu, 3 Aug 2006 06:24:15 +0100 Message-ID: > Here are the results from the analysis of a 26 radial system. > > 0.6 m -- Radial Z = 37.3 - j 28.1 -- Efficiency 15% > 0.8 m -- Radial Z = 30.5 - j 21.0 > 1.0 m -- Radial Z = 26.2 - j 16.9 > 1.2 m -- Radial Z = 23.2 - j 14.2 > 1.4 m -- Radial Z = 20.9 - j 12.4 > 1.6 m -- Radial Z = 19.1 - j 11.1 > 1.8 m -- Radial Z = 17.6 - j 10.1 -- Efficiency 21.0% > 2.0 m -- Radial Z = 16.2 - j 9.4 > 2.2 m -- Radial Z = 15.1 - j 8.8 > 2.4 m -- Radial Z = 14.0 - j 8.4 > 2.6 m -- Radial Z = 13.0 - j 8.0 > 2.8 m -- Radial Z = 12.1 - j 7.7 > 3.0 m -- Radial Z = 11.3 - j 7.4 > 3.2 m -- Radial Z = 10.4 - j 7.1 -- Efficiency 24.5% > 3.4 m -- Radial Z = 9.7 - j 6.8 > 3.6 m -- Radial Z = 8.9 - j 6.5 > 3.8 m -- Radial Z = 8.2 - j 6.2 > 4.0 m -- Radial Z = 7.5 - j 5.8 > 4.2 m -- Radial Z = 6.9 - j 5.5 > 4.4 m -- Radial Z = 6.4 - j 5.1 > 4.6 m -- Radial Z = 5.8 - j 4.7 > 4.8 m -- Radial Z = 5.4 - j 4.3 > 5.0 m -- Radial Z = 5.0 - j 3.9 -- Efficiency 27.8% > 5.2 m -- Radial Z = 4.6 - j 3.5 > 5.4 m -- Radial Z = 4.3 - j 3.1 > 5.6 m -- Radial Z = 4.0 - j 2.7 > 5.8 m -- Radial Z = 3.7 - j 2.3 > 6.0 m -- Radial Z = 3.5 - j 2.0 > 6.2 m -- Radial Z = 3.3 - j 1.6 > 6.4 m -- Radial Z = 3.1 - j 1.3 > 6.6 m -- Radial Z = 3.0 - j 0.9 > 6.8 m -- Radial Z = 2.9 - j 0.6 > 7.0 m -- Radial Z = 2.8 - j 0.3 > 7.2 m -- Radial Z = 2.7 + j 0.01 > 7.4 m -- Radial Z = 2.6 + j 0.3 > 7.6 m -- Radial Z = 2.6 + j 0.6 > 7.8 m -- Radial Z = 2.6 + j 0.9 > 8.0 m -- Radial Z = 2.5 + j 1.1 -- Efficiency 31.1% > . > . > 10.0 m -- Radial Z = 3.0 + j 3.3 -- Efficiency 32.6% > > Where I have shown the efficiency as sky wave power > out. The input impedance is that of all radials, so for > a single radial the input Zr must be Ztr * 26. > =========================================== Frank, The input impedance of 26 radials is NOT equal to all 26 connected in parallel. There is a non-linear relationship between the number N and input impedance because they share the same volume of soil at least when they are short. For 26 radials the resonant effects have disappeared which I cannot explain. Yet attenuation is the same, Zo converges on Zin at approximately 8 or 10 metres as before. You appear to have automated the results. Can you do a large number of radials, say around 100, from 0.4 to 8.0 metres? And can you do a small number of radials such as 6 or 8, from 0.4 to 8.0 metres? Article: 227623 of rec.radio.amateur.antenna From: "Reg Edwards" References: <9lcAg.39529$F8.1099@fe3.news.blueyonder.co.uk> <2bl2d25ingi88ch2k7pnkleke1vpd2emtc@4ax.com> Subject: Re: Magloop capacitor padding? Date: Thu, 3 Aug 2006 06:50:51 +0100 Message-ID: Lee, You can greatly increase the Q of a long length of coax cable by cutting it into 7 equal short lengths. Then put six lengths round one length and connect all seven in parallel. In theory, this increases Q by 7*7 = 49 times for the same capacitance. And it occupies less space. But when outdoors it is more difficult to seal against the weather. ---- Reg, G4FGQ Article: 227624 of rec.radio.amateur.antenna From: "Lee" References: Subject: Re: Magloop capacitor padding? Message-ID: Date: Thu, 03 Aug 2006 08:24:49 GMT "Lee" wrote in message news:Ho9Ag.45055$9d4.14908@fe2.news.blueyonder.co.uk... > Hi!.... > > I`ve just built a magloop 5`square and i find the variable cap only tunes > down to 4.45mhz.. > can i pad the cap out with a coaxial ur213 stub to reach 3.5mhz ???.... > > Lee.......G6ZSG..... > > (The 1metre loop works fine - 15 to 7mhz ).. :-) > > Sorted!!!!...... I rebuilt my variable capacitor and found a bad link in a bank of stator vanes ...effectively, only half the stators were coupled ..... i can now cover 80 metres.....yippee!!!.... Thanks for everyones help and advice.....find me on 3.697megs....... ;-) or, more likely, 3.733megs, QRV SSTV, analogue or digital.... Regards..... Lee......G6ZSG..... Article: 227625 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Thu, 03 Aug 2006 12:00:39 GMT Owen Duffy wrote: > On Thu, 3 Aug 2006 03:37:05 +0100, "Reg Edwards" > wrote: > >> I must admit, rules of thumb are quite adequate for coaxial chokes. >> Almost anything will work. Very often things will work quite well >> without a choke at all. ;o) > > But the Rule Of Thumb to avoid (presumably) parallel resonance of the > choke for the reasons given is ROT. Wouldn't the resonant circulating currents be at their highest magnitudes at the parallel resonant point and therefore the I^2*R losses in the coil be greater at that frequency than on either side of self-resonance? (I explained that avoiding self resonance is only a personal preference.) -- 73, Cecil http://www.qsl.net/w5dxp Article: 227626 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Question on carbon fibre fishing rod References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <1154575669.483390.122580@h48g2000cwc.googlegroups.com> Message-ID: Date: Thu, 03 Aug 2006 12:06:43 GMT n3ox.dan@gmail.com wrote: > My intuition about the rod and wire in parallel appears to be incorrect > unless the resistance of the rod is quite low, at least on 7MHz. > Separated and insulated from the rod seems to work quite well on 7MHz. My South Bend Sunny Day SD-20 pole doesn't show any DC resistance even when the paint is scraped off. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227627 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: neighborhood antenna restrictions Date: Thu, 03 Aug 2006 08:46:59 -0400 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com> Bill Turner wrote: > ORIGINAL MESSAGE: > > On Wed, 02 Aug 2006 23:07:41 -0400, Mike Coslo > wrote: > >> and I definitely wouldn't live in SoCa. > > ------------ REPLY SEPARATOR ------------ > > The only thing we need to make you feel right at home would be > humidity, ice storms and snow. Tell me about it! At least you do have lower humidity to go with your heat waves. Nothing quite so fun as 100 degrees at 90 percent humidity. Heck, I went up to Canada last weekend looking for a little relief. No such luck. Yuck. > We're working on it. I'll get back to you. > > Bill, W6WRT > looking for his snowshoes Article: 227628 of rec.radio.amateur.antenna From: Al Klein Subject: Re: If you had to use CW to save someone's life, would that person die? Message-ID: <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> <1153564701.965658.219410@p79g2000cwp.googlegroups.com> <1153584132.692529.177920@i3g2000cwc.googlegroups.com> <0ro4c2d13dq9i23ab98uiiql3spgmhfi22@4ax.com> <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> Date: Thu, 03 Aug 2006 08:56:36 -0400 On 2 Aug 2006 20:05:21 -0700, hot-ham-and-cheese@hotmail.com wrote: >Al Klein wrote: >> On 23 Jul 2006 07:26:05 -0700, hot-ham-and-cheese@hotmail.com wrote: >> >> >how balanced is to to place CW over all over ham knowledge? >> >> No one is, any more than by requiring people to know the law one is >> >> putting the law "over all ham knowledge". >> >CW is pass/fail. To fail CW denies all HF privs (except for Alaska). >> Theory is also pass/fail. To fail to get the required number of >> correct answers denies all privs - HF, VHF, UHF ... >There is no pass/fail practical for SSB, FM, AM, FSTV, SSTV, RTTY, FAX, >Packet, PSK, etc, etc, etc. There's no test at all, so those claiming that the reason they want a test for CW dropped because it's not "modern" have no argument - they want no test for FSTV, SSTV, RTTY (which is also pretty old hat), packet, PSK, etc. They want no test at all, unless they can memorize a few answers to "pass" it. >> >> >How progressive is it? >> >> How progressive is it to not require people to know ... oh, yeah, >> >> that's progressive, since the new thing is to hand out licenses >> >> because people have some kind of "right" to get on the air. >> >Then why is it with the prospect of losing the CW Exam, that you'se >> >guys want to "beef up" the written exams? >> We don't. >That is not true. Sure it is. "Beefing up" the written exam is a counter to "drop CW because it's old fashioned". If you want modern you want the testing to be turned from CW to modern modes. Those who want CW dropped just want what they can't memorize dropped so they can get a ticket without really being tested on anything. Actually knowing anything is so old fashioned, isn't it? >> We want to get back the level it used to be before it was >> dumbed down to the point that you could almost pass it if you never >> heard of the FCC, ham radio or electronics. >You're referring to the Conditional license, right? No, I'm not addressing *where* the test is held at all - I'm addressing *whether* there's any real test, which there isn't, except for CW right now. Spitting out something you memorized is only a test of memory. >> Just by guessing at the >> answers. It used to require that you draw (was it 3?) schematics. >You tell me? Was it 2 or was it 3? I don't remember after almost 50 years - but I could still draw them today, and it's not a test of remembering what's on the test, it's a test of knowing what's in a radio. >> From scratch. Let's see how many people could do that today. A >> Colpitts oscillator, a Hartley oscillator and some other circuit that >> I've forgotten at the moment. >You should self-modify your license and cease amateur operation until >you remember. Why? Testing isn't about memory, it's about knowledge. >The amateur is self-policing, and you no longer meet your own standard. Sure I do. The test wasn't to remember what circuits to draw, it was to draw them. And I can draw them any time. >> They're still as relevant today as they were 50 years ago. >Other things are relevant today that weren't even known 50 years ago. So let's have them on the test. Oops, that's right - no more relevant testing, isn't that what people are asking for? Just give me the answers so I can memorize them and pick them out on the test. >> >> >how loyal is it to denny the nation the benifits of allowing more >> >> >operators >> >> What "benefits" does the country get from more people using radios who >> >> don't know the first thing about them? (Whatever "denny" means.) >> >It's always been that way. You could even buy Heathkits already >> >assembled. >> But you had to actually *know* a little theory to use one legally. >No you didn't. Yes, you did - you had to pass a test to show that you did. All you have to do now is memorize a few answers. >I used radios in the military. I never used a CW key in the military. >I never jammed another operator, although Brandywine asked me to reduce >power once. But you had to learn how to use the radios. Hams today don't - they memorize a few answers, buy equipment and get on the air - with no understanding of what they're doing, and no desire to learn. >> That's exactly what he's talking about. Give someone a radio and a >> "license" to use it and he'll "acquire the skill to be ready for >> service to country and community". That's what Mark said, right up >> above. How does one acquire skill by playing radio? >We self-train. You may, but I can see from many of the comments that have been posted here that a lot of people don't. They don't want to learn, they want to get on the air. Period. > It is a continuous process of improvements. You >mistakenly believe that at the conclusion of The Exam, the "operator" >is 100%. And you mistakenly believe that most hams today want to learn how to operate properly. Listen to 75 some evenings. >> But that's what Mark and his ilk want - we'll have "skilled operators" >> if we allow people to buy radios and put them on the air with no skill >> or knowledge. By osmosis? Or by magic? >I've listened to emergency responders on a scanner before. They don't >use Morse Code, they don't use CW. They use FM/Voice. Somehow they >are effective at it, not having taken a Morse Code test. How can this >be? They were trained. >> So you'd get a license not knowing CW, build a radio (you couldn't buy >> one then) and ... what? Sit and look at it. Some things are just too >> obvious to need mentioning. >Please diagram that radio from "Scratch." Any time. Filter or phasing? BFO receive or quadrature detection? I've designed them, built them and used them, and still could. >> Evidently not, or I'd be the only one in the world advocating that a >> test should actually test for something. There are actually millions >> of us who don't think lack of instant gratification is the worst thing >> in the world. >Dial 911 and tell the operator that you don't need instant >gratification, take your time. Very bad example of an attempt at sarcasm and a misunderstanding of "gratification". >> What next? DXCC awards for those who *want* to work 100 countries? >You seem to be confused. DXCC is an award offered by the ARRL, not the >FCC. It has nothing to do with licensing. But an award for wanting has to do with "I want it so it's my right to have it", which is what I'm talking about. No one has any "right" to get on the air. Article: 227629 of rec.radio.amateur.antenna From: Buck Subject: Re: Rule of Thumb for coax chokes Message-ID: References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> Date: Thu, 03 Aug 2006 09:01:06 -0400 On Wed, 02 Aug 2006 21:17:04 GMT, "Tom Donaly" wrote: >But then you have to drink 2 liters of wet, sticky, gooey, sickeningly >sweet, soda pop. >73, >Tom Donaly, KA6RUH Or look in the nearest garbage can or dumpster. Of course, there are two liter bottles of water as well. :) -- 73 for now Buck N4PGW Article: 227630 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 3 Aug 2006 06:03:09 -0700 Message-ID: <1154610189.274197.177730@h48g2000cwc.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Probably not carbon fiber tho, right? I doubt it's possible to make a carbon fiber pole without end-to-end DC continuity. It could be high resistance, but I think you're always going to have fiber-to-fiber contact along the whole length of the pole. Carbon fiber, just as a point of general information in this thread, seems to have about 800 times the resistivity of copper according to matweb.com, and about 20 times the resisivity of 304 stainless steel. Not something that will make for a great radiator. If you assume fairly low frequency such that the skin depth in carbon fiber is deep enough that current will flow uniformly in a 1.6mm (1/16 inch) tube wall, and uniformly in a 1mm wire, you need a 10cm (4 inch) carbon fiber tube to match the 1mm wire in conductor loss! Interestingly enough, I read recently (I don't remember if it was QST or on the web) about someone who was using a fiberglass fishing pole for a vertical antenna and had significant detuning problems until they moved the wire far away from the pole. I, on the other hand, built a center loaded 40m antenna on a pair of fiberglass poles and it tuned exactly as one of Reg's programs and EZNEC said it would, suggesting that my poles are fairly good insulators. I still think I'd like a carbon fiber fishing rod... sounds nice and strong. Maybe it's best used as center supports for inverted vees and the like, and for carefully considered vertical applications. Dan > > My South Bend Sunny Day SD-20 pole doesn't show any DC > resistance even when the paint is scraped off. > -- > 73, Cecil http://www.qsl.net/w5dxp Article: 227631 of rec.radio.amateur.antenna From: gwatts Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> Message-ID: Date: Thu, 03 Aug 2006 13:28:11 GMT Tom Donaly wrote: > Cecil Moore wrote: > >> Reg Edwards wrote: >> >> 2 liter pop bottles are in abundance in the US. If a coil >> form is used for a coax choke, that's the most likely. > > > But then you have to drink 2 liters of wet, sticky, gooey, sickeningly > sweet, soda pop. > 73, > Tom Donaly, KA6RUH We get 'sparkling water' in 2l bottles because we like the fizzy feel to our beverages. They also have club soda and soda water in 2l bottles. Keep cool, Galen, W8LNA Article: 227632 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: If you had to use CW to save someone's life, would that person References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> <1153564701.965658.219410@p79g2000cwp.googlegroups.com> <1153584132.692529.177920@i3g2000cwc.googlegroups.com> <0ro4c2d13dq9i23ab98uiiql3spgmhfi22@4ax.com> <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> Message-ID: Date: Thu, 03 Aug 2006 13:53:40 GMT Al Klein wrote: > Testing isn't about memory, it's about knowledge. Then why isn't knowledge of Morse code and the CW mode sufficient? Why must someone be forced to memorize the individual characters? -- 73, Cecil, http://www.qsl.net/w5dxp Article: 227633 of rec.radio.amateur.antenna From: "K4YZ" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 3 Aug 2006 07:12:51 -0700 Message-ID: <1154614371.351691.272240@s13g2000cwa.googlegroups.com> References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> Cecil Moore wrote: > Al Klein wrote: > > Testing isn't about memory, it's about knowledge. > > Then why isn't knowledge of Morse code and the CW mode > sufficient? Why must someone be forced to memorize > the individual characters? Probably, Cecil, since it would then make it difficult to pass the test. "I" There. You just got ONE "character" of several electronics-related formulas. Now do something with it without knowing the rest of the "characters" that go with it. 73 Steve, K4YZ Article: 227634 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Thu, 03 Aug 2006 07:18:16 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com> ORIGINAL MESSAGE: On Thu, 03 Aug 2006 08:46:59 -0400, Michael Coslo wrote: >Tell me about it! At least you do have lower humidity to go with your >heat waves. Nothing quite so fun as 100 degrees at 90 percent humidity. ------------ REPLY SEPARATOR ------------ So true. We get 100 degrees a lot but the humidity is usually no more than about 25% and is often lower. It's quite nice, really, until the brush fires begin. :-) Bill, W6WRT Article: 227635 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: If you had to use CW to save someone's life, would that person References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> <1153564701.965658.219410@p79g2000cwp.googlegroups.com> <1153584132.692529.177920@i3g2000cwc.googlegroups.com> <0ro4c2d13dq9i23ab98uiiql3spgmhfi22@4ax.com> <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> Message-ID: Date: Thu, 03 Aug 2006 14:26:51 GMT K4YZ wrote: > Cecil Moore wrote: >> Then why isn't knowledge of Morse code and the CW mode >> sufficient? Why must someone be forced to memorize >> the individual characters? > > Probably, Cecil, since it would then make it difficult to pass the > test. You missed the point. The Morse code skill exam requires memorizing the characters. Memorizing is being condemned as an evil act. Since memorizing is evil, the Morse code skill exam should be the first thing to be eliminated. -- 73, Cecil, http://www.qsl.net/w5dxp Article: 227636 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Thu, 03 Aug 2006 14:40:09 GMT Owen Duffy wrote: > But the Rule Of Thumb to avoid (presumably) parallel resonance of the > choke for the reasons given is ROT. The self-resonance to be avoided is 1/2WL self-resonance, e.g. 20 turns on 10m. I apologize for confusing the two self-resonant concepts. -- 73, Cecil, http://www.qsl.net/w5dxp Article: 227637 of rec.radio.amateur.antenna From: "Jerry Martes" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Message-ID: Date: Thu, 03 Aug 2006 14:52:00 GMT "Cecil Moore" wrote in message news:HzlAg.841$1f6.69@newssvr27.news.prodigy.net... > Owen Duffy wrote: >> On Thu, 3 Aug 2006 03:37:05 +0100, "Reg Edwards" >> wrote: >> >>> I must admit, rules of thumb are quite adequate for coaxial chokes. >>> Almost anything will work. Very often things will work quite well >>> without a choke at all. ;o) >> >> But the Rule Of Thumb to avoid (presumably) parallel resonance of the >> choke for the reasons given is ROT. > > Wouldn't the resonant circulating currents be at their > highest magnitudes at the parallel resonant point and > therefore the I^2*R losses in the coil be greater at > that frequency than on either side of self-resonance? > (I explained that avoiding self resonance is only a > personal preference.) > -- > 73, Cecil http://www.qsl.net/w5dxp Hi Cecil Doesnt the increase of impedance of the parallel resonant "balun" discourage current from flowing into it? I considered that the source impedance is constant and the "balun" impedance rises as resonance is approached. I figured the circulating current would be Q times the current thru it, but the current thru it drops as its impedance rises. If I'm wrong, I've been lucky so far. Jerry . Article: 227638 of rec.radio.amateur.antenna From: "clfe" References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> <1153564701.965658.219410@p79g2000cwp.googlegroups.com> <1153584132.692529.177920@i3g2000cwc.googlegroups.com> <0ro4c2d13dq9i23ab98uiiql3spgmhfi22@4ax.com> <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Thu, 3 Aug 2006 11:01:58 -0400 Message-ID: <44d20fd9$0$2919$ecde5a14@news.coretel.net> "Cecil Moore" wrote in message news:LInAg.689$%j7.344@newssvr29.news.prodigy.net... > K4YZ wrote: >> Cecil Moore wrote: >>> Then why isn't knowledge of Morse code and the CW mode >>> sufficient? Why must someone be forced to memorize >>> the individual characters? >> >> Probably, Cecil, since it would then make it difficult to pass the >> test. > > You missed the point. The Morse code skill exam requires > memorizing the characters. Memorizing is being condemned > as an evil act. Since memorizing is evil, the Morse code > skill exam should be the first thing to be eliminated. > -- > 73, Cecil, http://www.qsl.net/w5dxp In some cases, it "could" be said that hairs are being split. To have "knowledge" of the code - could mean basically - you know it exists and why it is used. To "know" the Morse Code, usually refers to KNOWING the characters sufficiently to use them at whatever speed it is you can. On the other hand, someone who isn't involved could say - that a Ham operator is "knowledgable" in the code. Heck, to someone not IN Ham radio - they could easily assume a NO CODE tech - KNOWS code. Memory plays a big part be it with learning CODE OR Electronics formulas. MEMORY plays a huge part in "remembering" how to solder correctly and so on. You have to MEMORIZE these things just like code characters - to be proficient. Just like MEMORIZING traffic signs and so on - to get your license to drive. I think there is too big a deal being made here. It comes down to - if you want to do ANYTHING - be it do morse code, drive, parachuting, whatever - you have to MEMORIZE SOMETHING - to make it happen. Lou/ka3flu Article: 227639 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Date: Thu, 3 Aug 2006 16:03:29 +0100 Message-ID: "Cecil Moore" wrote > > Wouldn't the resonant circulating currents be at their > highest magnitudes at the parallel resonant point and > therefore the I^2*R losses in the coil be greater at > that frequency than on either side of self-resonance? > (I explained that avoiding self resonance is only a > personal preference.) ====================================== Hi Cec, The exceedingly small power loss in the choke depends on the impedance of the power source which is driving it. It is a question of non-conjugate mis-matching. But at self-resonance, and indeed anywhere else, you can forget all about power loss. Especially as no ferrite material is involved. If you have bothered to check your "rule-of-thumb" and "turns-per-metre-of-wavelength" against program SELFRES3, then, provided results are in the same ball-park, all will be more than satisfactory. SELFRES3 is itself only approximate. The choke's self-resonant frequency is somewhat indeterminate as soon as anything is connected to it. A hank of a bunched number of turns is quite good enough as a coaxial choke. It is only necessary to know the number of turns and the diameter. Construction neatness helps with estimating the number of turns but has hardly any effect on performance. Coaxial chokes are a relatively unimportant circuit component. Exactly what they are supposed to do is aways doubtful unless they are used as baluns. I wonder why I am spending so much time discussing the subject. Praps it's because I have nothing better to do. ---- Reg. Article: 227640 of rec.radio.amateur.antenna From: "clfe" References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> <1153564701.965658.219410@p79g2000cwp.googlegroups.com> <1153584132.692529.177920@i3g2000cwc.googlegroups.com> <0ro4c2d13dq9i23ab98uiiql3spgmhfi22@4ax.com> <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Thu, 3 Aug 2006 11:31:37 -0400 Message-ID: <44d216cb$0$2920$ecde5a14@news.coretel.net> "clfe" wrote in message news:44d20fd9$0$2919$ecde5a14@news.coretel.net... > > "Cecil Moore" wrote in message > news:LInAg.689$%j7.344@newssvr29.news.prodigy.net... >> K4YZ wrote: >>> Cecil Moore wrote: >>>> Then why isn't knowledge of Morse code and the CW mode >>>> sufficient? Why must someone be forced to memorize >>>> the individual characters? >>> >>> Probably, Cecil, since it would then make it difficult to pass the >>> test. >> >> You missed the point. The Morse code skill exam requires >> memorizing the characters. Memorizing is being condemned >> as an evil act. Since memorizing is evil, the Morse code >> skill exam should be the first thing to be eliminated. >> -- >> 73, Cecil, http://www.qsl.net/w5dxp > > In some cases, it "could" be said that hairs are being split. To have > "knowledge" of the code - could mean basically - you know it exists and > why it is used. To "know" the Morse Code, usually refers to KNOWING the > characters sufficiently to use them at whatever speed it is you can. On > the other hand, someone who isn't involved could say - that a Ham operator > is "knowledgable" in the code. Heck, to someone not IN Ham radio - they > could easily assume a NO CODE tech - KNOWS code. Just to clarify my point - many "assume" a Ham Operator - regardless the license - KNOWS code. So, if a "No Code" tech simply says "I"M A HAM OPERATOR" to someone not knowing the license class structure, the "assumption is made. AND unless that NC tech clarifies it, the unsuspecting person will go on in ignorance "assuming" ALL hams "know" code. Morse Code (per my recollection) has always been and most likely - even if only in history books - always will be known and associated with HAM RADIO. lou Article: 227641 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Thu, 03 Aug 2006 15:33:02 GMT Jerry Martes wrote: > Doesnt the increase of impedance of the parallel resonant "balun" > discourage current from flowing into it? My bad for confusing 1/4WL self-resonance with 1/2WL self-resonance. A choke is essentially non-functional at the 1/2WL self-resonant point. That's the configuration to be avoided. -- 73, Cecil, http://www.qsl.net/w5dxp Article: 227642 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: If you had to use CW to save someone's life, would that person References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> <1153564701.965658.219410@p79g2000cwp.googlegroups.com> <1153584132.692529.177920@i3g2000cwc.googlegroups.com> <0ro4c2d13dq9i23ab98uiiql3spgmhfi22@4ax.com> <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> Message-ID: Date: Thu, 03 Aug 2006 15:35:11 GMT clfe wrote: > It comes down to - if you want to do ANYTHING - be it do morse code, drive, > parachuting, whatever - you have to MEMORIZE SOMETHING - to make it happen. My point exactly! I'm not the one saying that memorizing is evil. -- 73, Cecil, http://www.qsl.net/w5dxp Article: 227643 of rec.radio.amateur.antenna From: "Frank's" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> Subject: Re: Radiating Efficiency Message-ID: Date: Thu, 03 Aug 2006 15:39:59 GMT > Frank, > > The input impedance of 26 radials is NOT equal to all 26 connected in > parallel. There is a non-linear relationship between the number N and > input impedance because they share the same volume of soil at least > when they are short. > > For 26 radials the resonant effects have disappeared which I cannot > explain. Yet attenuation is the same, Zo converges on Zin at > approximately 8 or 10 metres as before. > > You appear to have automated the results. Can you do a large number > of radials, say around 100, from 0.4 to 8.0 metres? > > And can you do a small number of radials such as 6 or 8, from 0.4 to > 8.0 metres? Reg, I suspected as much concerning the input impedance of a number or radials. Note that my model was 36 radials, not 26. 26 was simply a typo. Believe me there is no automation involved in running NEC, although the work is trivial. The 36 radial model was taking 13 minutes per run as I approached 8 m length radials. I can certainly model the small number of radials, which should not take too long. As for 100 radials; this exceeds the maximum number of junctions limit in NEC. This does not mean it cannot be done, there are work-arounds. Due to excessive computer time I will have to develop a model with a more realistic run time. I am interested in doing this for my own benefit, but it will take some time. I will be very busy for the next few weeks, but will be able to squeeze some time in occasionally. Frank Article: 227644 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Thu, 03 Aug 2006 15:39:26 GMT Reg Edwards wrote: > A hank of a bunched number of turns is quite good enough as a coaxial > choke. I got the 1/4WL and 1/2WL self-resonant points confused in my mind. A "bunched number of turns" causing 1/2WL self-resonance would function very poorly as a choke. -- 73, Cecil, http://www.qsl.net/w5dxp Article: 227645 of rec.radio.amateur.antenna From: ab2rc Subject: Re: If you had to use CW to save someone's life, would that person die? References: <1152931208.617498.208970@75g2000cwc.googlegroups.com> <1153564701.965658.219410@p79g2000cwp.googlegroups.com> <1153584132.692529.177920@i3g2000cwc.googlegroups.com> <0ro4c2d13dq9i23ab98uiiql3spgmhfi22@4ax.com> <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> Message-ID: Date: Thu, 03 Aug 2006 17:09:09 GMT On 2006-08-03, Cecil Moore wrote: > > You missed the point. The Morse code skill exam requires > memorizing the characters. Memorizing is being condemned > as an evil act. Since memorizing is evil, the Morse code > skill exam should be the first thing to be eliminated. Are you trying to confuse the issue by using logic? The (no)morse issue is nothing other than a purely emotional thing. FWIW - I took the test, I passed it (barely), I used it twice. AlMost all of my contacts are either 20m psk31 or 6m ssb. -- Alex/AB2RC Article: 227646 of rec.radio.amateur.antenna Subject: Re: Question on carbon fibre fishing rod From: Dave Oldridge References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> Message-ID: Date: Thu, 03 Aug 2006 17:33:47 GMT "Sal M. Onella" wrote in news:i3eAg.12676$lv.6904@fed1read12: > > wrote in message > news:1154555654.618018.192280@i42g2000cwa.googlegroups.com... >> Or if it is 1/4-wave resonant and is in relatively low-resistance >> contact with the groundplane. >> >> Dan >> > But loss will be induced in the rod only when the rod is near to >> > 1/2-wave resonant. >> > ---- >> > Reg. >> > > Tony, what happens if you load the transmitter into the rod, directly? > Upon reading that the end-to-end resistance of the pole may be about > an ohm, that idea was in my head instantly. Impedance to RF is a > different animal, of course but I would try it on low power, just to > measure SWR. And you don't have to do anything, really, to determine > whether you can _hear_ using it! > > I hope you keep us informed. Right, stick an analyzer on it and see what it actually does with real RF in it. -- Dave Oldridge+ ICQ 1800667 Article: 227647 of rec.radio.amateur.antenna From: "Jimmie D" References: <30954.oidi09.d0904.ddoi0@qkd.org> <1152929851.865986.4740@35g2000cwc.googlegroups.com> <_AVug.9493$PE1.1406@newsread2.news.pas.earthlink.net> <1153275616.225575.252170@m79g2000cwm.googlegroups.com> <44BDA4F3.7000706@fuse.net> <12brelk76dlj901@corp.supernews.com> Subject: Re: Morris Code -plus- Continuous Wave (CW) Radio Transmission -and- Semaphore Signals ? Do They Defining Amateur Radio ? Message-ID: Date: Thu, 3 Aug 2006 13:40:25 -0400 > The term "lid" may have originated from newbie Morse operators > laying a lid on top of the relay receiver to make it easier to > distinguish the dots from the dashes. > -- > 73, Cecil http://www.qsl.net/w5dxp My mother told me stories of learning morse code this way when she worked for the railroad. She then taught me morse code this way. For twenty yeasrs after that I always wanted to be a ham and finally got m ylicense at about age 35. I was fairly active for about 8 years and pretty much lost interest when my daughter was born. In the last couple of years I have been sporatially interested again but their alaways seems to be little projects and interest that pull me away from it. When I first went to work at tmy present job almost every tech that worked there was a ham. Just about all of them retired within a few years and nnd only a couple are still active on the ham bands. They pretty much all say that they just dont have time for it anymore. This is where ham radio is going, It is losing out to living. I havent gotten totally out of it yet and am occasionally involed. Usually working on an antenna project thinking I will become active again. I have been asked to assist some girl scouts in getting badges but I am having a lot of trouble finding scouts that are interested although the requirements are very minimal Article: 227648 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Date: Thu, 3 Aug 2006 18:49:40 +0100 Message-ID: Cecil, A choke consists of an inductance in parallel with its stray capacitance. It has only two terminals. Its loss can be represented, either by a small resistance in series with the inductance, or a very high resistance in shunt with the inductance and its shunt stray capacitance. What you mean by 1/4-wave and 1/2-wave resonance I have no idea and, in any case, has nothing to do with how the extremely simple circuit behaves. The best thing to do is to forget the whole thing and find something else of greater consequence to argue about. ---- Reg. Article: 227649 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: neighborhood antenna restrictions Date: Thu, 03 Aug 2006 11:11:33 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> Bill Turner wrote: > ORIGINAL MESSAGE: > > On Wed, 2 Aug 2006 14:04:30 -0700, "Bob Agnew" wrote: > > > >>Do you know of any place in Southern California that doesn't have such >>restrictions? > > > ------------ REPLY SEPARATOR ------------ > > Yep. I live 30 miles due north of Palm Springs and the jackrabbits > don't care at all. > > Bill, W6WRT You're next, Bill. Enjoy it while it lasts! :-) ac6xg Article: 227650 of rec.radio.amateur.antenna From: "Denny" Subject: Re: Rule of Thumb for coax chokes Date: 3 Aug 2006 11:40:56 -0700 Message-ID: <1154630456.194673.195900@s13g2000cwa.googlegroups.com> References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> While you guys were chewing on this I decided to repair a broken coax on the 80 meter array for beaming europe... Temp 96 degrees... Wind blowing like snot with a storm front coming in and cumulus building to the West and getting ready for a climax... I climb slowly to 100 feet (puffing and sweating.. It can't be cause I'm out of shape! 'Must be the heat', I mutter)... After a bit of maneuvering, and using one foot to snag a drooping wire I untangle the 70 feet of coax that had flopped back against the tower and managed to wrap itself on everything in sight... I capture the center insulator of the driven element that is waving widly in the wind... After some ten minutes of stripping and clipping and clamping I have the coax reattached... I drag out the propane soldering pencil... I can't keep it lit in the wind... I even resort to lighting it inside my tool pouch.. All I succeed in doing is burning a hole in the pouch... Jeez Louise... I give up and climb down... I left the connected parts taped to the tower leg... I'll have to solder on a calmer day... The saving grace is that I don't have a coaxial choke to deal with... denny Article: 227651 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <1154575669.483390.122580@h48g2000cwc.googlegroups.com> <1154610189.274197.177730@h48g2000cwc.googlegroups.com> Subject: Re: Question on carbon fibre fishing rod Date: Thu, 3 Aug 2006 21:47:08 +0200 Message-ID: <44d252bd$0$35072$4fafbaef@reader4.news.tin.it> I wish to thank all people contributing to understanding the issue. The discussion confirms me that precisely predicting what happens when = using a carbon fibre rod is not easy. On the other hand that rod is so = appealing for realizing a stealth antenna leaning on the balcony = railing.... Imagine a 27-foot rod, coming down to just 4 feet, weighing = just 2 pounds or so, having a diameter of less than 1 inch at the base = and about 0.08 inch at the top.... and standing well straight! So, what I plan to do is the following: - buy the rod @ about 100$ (it will so also be possible to make more = precise resistance measurements than those I can take at the store) - quickly build a classic 20-meter ground plane test antenna, by = extending the rod just as much as needed and taping an insulated copper = wire on the rod, parallel to it. I will connect the copper wire only at = the rod top and at its base which will be insulated from ground and = connected to the coaxial cable center conductor. I will then put four = radials on the ground, connected to the coaxial cable braid=20 - I will apply 1500W RF for some ten minutes. Assuming that the rod = causes a loss of just 0.5 dB, this would mean dissipating 163 W on the = rod that, considering its low mass, should become hot enough to detect = it! Then, if the rod does not get hot at all, I can conclude that no = virtually no power gets dissipated in it. - I will repeat the experiment by keeping the copper wire fully = insulated from the rod, though still taped on it =20 - finally, I will report the test results here. 73 to all=20 Tony I0JX Article: 227652 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> Subject: Re: Question on carbon fibre fishing rod Date: Thu, 3 Aug 2006 21:51:00 +0200 Message-ID: <44d253a5$0$35069$4fafbaef@reader4.news.tin.it> > Tony, what happens if you load the transmitter into the rod, directly? = Upon > reading that the end-to-end resistance of the pole may be about an = ohm, that > idea was in my head instantly. Impedance to RF is a different animal, = of > course but I would try it on low power, just to measure SWR. And you = don't > have to do anything, really, to determine whether you can _hear_ using = it! >=20 > I hope you keep us informed. Hi Sal, what you suggest is certainly a possibility. But until I do not buy the = rod, it is difficult for me to precisely measure the rod resistance and = then decide whether using the rod alone makes real sense. I have finally decided to buy the rod, so I will also try to use it as a = radiator, with no copper wire taped on it. 73 Tony I0JX Article: 227653 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> <44d0fe0d$0$35074$4fafbaef@reader4.news.tin.it> <1154548645.376883.303310@m73g2000cwd.googlegroups.com> <44d10f83$0$35078$4fafbaef@reader4.news.tin.it> <1154555178.548566.311570@75g2000cwc.googlegroups.com> Subject: Re: Question on carbon fibre fishing rod Date: Thu, 3 Aug 2006 21:51:45 +0200 Message-ID: <44d253d1$0$35079$4fafbaef@reader4.news.tin.it> I wish to thank all people contributing to understanding the issue. The discussion confirms me that precisely predicting what happens when = using a carbon fibre rod is not easy. On the other hand that rod is so = appealing for realizing a stealth antenna leaning on the balcony = railing.... Imagine a 27-foot rod, coming down to just 4 feet, weighing = just 2 pounds or so, having a diameter of less than 1 inch at the base = and about 0.08 inch at the top.... and standing well straight! So, what I plan to do is the following: - buy the rod @ about 100$ (it will so also be possible to make more = precise resistance measurements than those I can take at the store) - quickly build a classic 20-meter ground plane test antenna, by = extending the rod just as much as needed and taping an insulated copper = wire on the rod, parallel to it. I will connect the copper wire only at = the rod top and at its base which will be insulated from ground and = connected to the coaxial cable center conductor. I will then put four = radials on the ground, connected to the coaxial cable braid=20 - I will apply 1500W RF for some ten minutes. Assuming that the rod = causes a loss of just 0.5 dB, this would mean dissipating 163 W on the = rod that, considering its low mass, should become hot enough to detect = it! Then, if the rod does not get hot at all, I can conclude that no = virtually no power gets dissipated in it. - I will repeat the experiment by keeping the copper wire fully = insulated from the rod, though still taped on it =20 - finally, I will report the test results here. 73 to all=20 Tony I0JX Article: 227654 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 3 Aug 2006 14:38:14 -0700 Message-ID: <1154641094.883360.172960@m79g2000cwm.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Tony, It's probably worth mentioning, that all of the lossy situations I encountered in EZNEC also caused fairly significant modification of the feedpoint impedance. I suppose it makes sense; this is a necessary condition for coupling significant power into the rod, and could potentially give you extra information beyond just measuring the temperature rise. 73, Dan > I have finally decided to buy the rod, so I will also try to use it as a radiator, with no copper wire taped on it. > > 73 > > Tony I0JX Article: 227655 of rec.radio.amateur.antenna From: "Bob Agnew" References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com> Subject: Re: neighborhood antenna restrictions Message-ID: Date: Thu, 3 Aug 2006 15:12:01 -0700 > > Same difference. I wouldn't live in one of those deed restricted > developments, and I definitely wouldn't live in SoCa. > I didn't have any choice. I had to take the job here in order to support my family. Good paying job openings for MSEE's were not all that abundant in 1971. "Mike Coslo" wrote in message news:99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com... > Bob Agnew wrote: >> Do you know of any place in Southern California that doesn't have such >> restrictions? >> > > Same difference. I wouldn't live in one of those deed restricted > developments, and I definitely wouldn't live in SoCa. > > We have choices. > > - 73 de Mike KB3EIA - Article: 227656 of rec.radio.amateur.antenna From: "Bob Agnew" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> <44d0fe0d$0$35074$4fafbaef@reader4.news.tin.it> <1154548645.376883.303310@m73g2000cwd.googlegroups.com> <44d10f83$0$35078$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Message-ID: Date: Thu, 3 Aug 2006 15:19:29 -0700 Perhaps a fiberglass rod would be a better choice? "Antonio Vernucci" wrote in message news:44d10f83$0$35078$4fafbaef@reader4.news.tin.it... Hi Dan > If you can measure the resistance at more than one point on the surface > of the rod, does this imply that the rod surface is conductive > everywhere along its length? I am not sure having fully understood your remark. I presume that, the materal being homogeneous, the rod surface is conductive everywhere the same way. The various elements of the rod touch each other, so there is electrical continuity along the whole rod. Clearly, toward the rod top, resistance will be higher due to the thinner diameter > If you could attach the wire to the rod so that it touches everywhere > along the length, then the current would divide between the rod and the > wire according to their respective resistance per length (most of the > current would flow in the wire) and the currents induced in the pole > would be in phase with the currents induced in the wire. I agree that currents would divide between the rod and the wire according to their respective resistance, but this is not my main worry as the very low-resistance copper wire would nearly fully bypass the rod resistance. What I am instead worried about is that, the rod being thick, the RF current may not be the same along the rod circumference. In other words, at the point of contact between the rod and the copper wire, the rod current could be lower than that at its opposite side. Such extra current could develop due to the rod electromagnetic coupling with the radiating wire. However, I am not sure whether my reasoning makes real sense > > I think it would help to have the wire attached at least at the bottom > of the pole and the top of the pole. > If you attach the wire only at the top and ground the bottom of the > pole, you make a rather lossy folded monopole. If you attach the wire > at both the top and bottom of the pole and insulate the whole structure > from ground, it's more like a cage monopople with one lossy wire and > one good wire. My idea is to have the wire attached at both the bottom and the top of the rod as you suggest. The bottom copper lead would also be connected to the center conductor of the coaxial feed cable (the cable braid would instead be connected to the radial system). Now an interesting case. Suppose that the copper wire is instead kept fully insulated from the rod (though very close to it). Would you expect power loss to occur in the conductive rod due to RF currents flowing through the rod due to its electromagnetic coupling with the radiating wire? 73 Tony I0JX Article: 227657 of rec.radio.amateur.antenna From: "Bob Agnew" References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com> Subject: Re: neighborhood antenna restrictions Message-ID: <5svAg.351$0F5.278@fed1read04> Date: Thu, 3 Aug 2006 16:15:13 -0700 "Wayne" wrote in message news:PavAg.7992$oz.3960@trnddc07... > > "Bob Agnew" wrote in message > news:RwuAg.346$0F5.150@fed1read04... >> > >>> Same difference. I wouldn't live in one of those deed restricted >>> developments, and I definitely wouldn't live in SoCa. >>> >> >> I didn't have any choice. I had to take the job here in order to support >> my family. >> Good paying job openings for MSEE's were not all that abundant in 1971. >> > Seems like those were the days when the last engineer leaving Seattle was > supposed to turn off the lights.....I ended up in NJ for a couple of years > during that timeframe. > Ah yes. I think I was at the Seattle Boeing facility once or twice, and also at St. Louis and several other of their places. Article: 227658 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <44d253a5$0$35069$4fafbaef@reader4.news.tin.it> <1154641094.883360.172960@m79g2000cwm.googlegroups.com> Subject: Re: Question on carbon fibre fishing rod Date: Fri, 4 Aug 2006 01:18:15 +0200 Message-ID: <44d28437$0$35073$4fafbaef@reader4.news.tin.it> > It's probably worth mentioning, that all of the lossy situations I > encountered in EZNEC also caused fairly significant modification of = the > feedpoint impedance. I suppose it makes sense; this is a necessary > condition for coupling significant power into the rod, and could > potentially give you extra information beyond just measuring the > temperature rise. What I plan to do is to measure SWR in three conditions, i.e. the rod = alone (no parallel copper wire), rod + wire connected at the two = extremes, and rod insulated from the radiating wire. The measured SWR = variation in the three cases will give me an indication of the feedpoint = impedance variation, which, as you say, can constitute an indicator of = ohmic losses presence. By means of a tuner, I will be able to deliver the desired amount of RF = power into the antenna for quite a wide feedpoint impedance range (and = SWR). I can use a short run of coaxial cable to feed the antenna, so the = cable loss variation for different SWR values will be negligible on 20 = meters.=20 73 Tony I0JX Article: 227659 of rec.radio.amateur.antenna From: sparkysko@gmail.com Subject: Re: Help with Antenna Date: 3 Aug 2006 16:53:42 -0700 Message-ID: <1154649222.197019.192660@h48g2000cwc.googlegroups.com> References: Kryptoknight wrote: > so there is no better ducky antenna than the one that came with this cb ?? > > any suggestions on a roof mounted thin stainless whip?? Hello! I was looking into this problem recently too. For the antenna, search on radioshacks website for "102". You'll find their 102" stainless antenna. They have an inventory locator on the website which will tell you which radioshack has it in stock (supposedly). If you have a non corporate radio shack (they're run semi-independent, and have their own stuff as well as radio shack stuff), they're more likely to carry the 102" even if the website says they don't have them. CALL AHEAD, it seems like they just lose their inventory somewhere, and can't find them when it says they have them (How you lose something that's 9 feet long, i have NO idea). Good luck on a roof mount. I've seen some roofmounts, and I believe some homemade ones. Kinda scary looking. I'm always concerned with the flex on the sheet metal. My nissan truck roof is tooo thin to mount a big whip on without a huge supporting washer (like 8 inches+). You're not really going to find just a thin metal wire antenna that's not 102". Everything shorter than that is going to have a coil. I also strongly suggest checking out your local truck stop. Radio shack mostly only sells a ball mount (the one they have supposedly sucks, since it doesn't have the 'teeth' to hold the ball in place well when you attack it, but ball types are one of the strongest!'. They also have mirror mounts. Which are only really useful if you have semi mirrors that are held on by metal poles. Or I guess if you have a roof rack (but then you'd need to get this ground well!). A compromise that I made is an under hood mount. It's kinda like an L bracket, so you open your hood, and right under the lip (on your car, not the hood) you can screw in the mount, These types allow you to have all the screws hidden below the hood, and the mount sticks up betwteen the hood crack. Then you can run a wire from this, under your hood, and through your firewall (usually you have rubber gromets for other wires already going through your firewall). The hood mounts are probably not strong enough for a 102" whip. The other option is magnet mount, with the four 6" magnets. They sell them online for like 30 or 40$. Those will hold anything. Only problem with magnet mounts is that they're more likely to pick up vehicle RFI noise! I picked up my blower motor for my AC, went away the minute I screwed the antenna into my sheet metal. Article: 227660 of rec.radio.amateur.antenna Subject: Re: Morris Code -plus- Continuous Wave (CW) Radio Transmission -and- Semaphore Signals ? Do They Defining Amateur Radio ? From: Slow Code References: <30954.oidi09.d0904.ddoi0@qkd.org> <1152929851.865986.4740@35g2000cwc.googlegroups.com> <_AVug.9493$PE1.1406@newsread2.news.pas.earthlink.net> <1153275616.225575.252170@m79g2000cwm.googlegroups.com> <44BDA4F3.7000706@fuse.net> <12brelk76dlj901@corp.supernews.com> Message-ID: Date: Fri, 04 Aug 2006 00:37:36 GMT "Jimmie D" wrote in news:hwqAg.40256$Nt.22359@bignews8.bellsouth.net: > >> The term "lid" may have originated from newbie Morse operators >> laying a lid on top of the relay receiver to make it easier to >> distinguish the dots from the dashes. >> -- >> 73, Cecil http://www.qsl.net/w5dxp > > My mother told me stories of learning morse code this way when she > worked for the railroad. She then taught me morse code this way. For > twenty yeasrs after that I always wanted to be a ham and finally got m > ylicense at about age 35. I was fairly active for about 8 years and > pretty much lost interest when my daughter was born. In the last couple > of years I have been sporatially interested again but their alaways > seems to be little projects and interest that pull me away from it. > > When I first went to work at tmy present job almost every tech that > worked there was a ham. Just about all of them retired within a few > years and nnd only a couple are still active on the ham bands. They > pretty much all say that they just dont have time for it anymore. This > is where ham radio is going, It is losing out to living. > > I havent gotten totally out of it yet and am occasionally involed. > Usually working on an antenna project thinking I will become active > again. I have been asked to assist some girl scouts in getting badges > but I am having a lot of trouble finding scouts that are interested > although the requirements are very minimal Yes. That's understandable. Hams these days don't want to act like hams, they like to be appliance operators. So kids don't see that CW is important and fun. All they see is hams gabbing on a microphone like any CB'er can do. SC Article: 227661 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Date: Fri, 4 Aug 2006 02:23:13 +0100 Message-ID: Cec, Can't you see that the first resonance corresponds to the parallel resonance of the inductance with its stray capacitance, and is what you call its 1/2-wave resonance? At your 1/2-wave resonance the input impedance is very high regardless of what the load impedance is on the other side. It does not behave anything like a transmission line. Higher frequency resonances, IF they exist, will be above and outside the amateur bands and of no interest to anybody. Interest lies only in either side of the first resonance. That is in the wide band of frequencies at which the impedance is greater than 1000 ohms or so. See program SELFRES3. ---- Reg. Article: 227662 of rec.radio.amateur.antenna From: "an old freind" Subject: Re: ARS License Numbers Date: 3 Aug 2006 18:33:47 -0700 Message-ID: <1154655227.803803.308580@i3g2000cwc.googlegroups.com> References: <1148005814.174874.234520@38g2000cwa.googlegroups.com> Slow Code wrote: > "J. D. B." wrote in > news:3f15e$44d0fb32$d06640f9$31962@FUSE.NET: > > > No, it's what happens when give people tests that are irrelevant to the > > state of the service and the world today. It's what happens when old > > timers keep the impression alive that ham radio is about code, tubes and > > other worthless old "technologies". It's what happens when we try to > > gate people out by making them pass the same worthless crap we had to > > pass because, "well I had to do it so they should have to do it" > > mentality. > > > > We already have a bunch of "retards" on HF and have for the thirty plus > > years that I can remember. Testing didn't keep the low-lifes out then, > > and it is not going to do it now. > > > > Learn to face reality. The old tests are what has brought on the > > problems - especially the worthless code tests. > > > > It's not about "dumbing down" the testing. It's about the need to > > modernize the testing, and our hanging onto the old and outdated for far > > too long, that has caused the problems we face today. > > > > Having to learn CW isn't preventing you from modernizing, You're just > lazy. Now go play with your model cho-cho trains. more libel you sound just liek wismen and robeson > > SC Article: 227663 of rec.radio.amateur.antenna From: "Bindy" Subject: Re: Rule of Thumb for coax chokes Date: 3 Aug 2006 19:34:21 -0700 Message-ID: <1154658861.371239.283890@i3g2000cwc.googlegroups.com> References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> Cecil Moore wrote: > Based on some calculations I did today, I am offering > an original rule of thumb (as far as I know). Regarding > a coax choke, when deciding how many turns of coax to put > on a 2 liter pop bottle at two turns per inch, one needs > to avoid the self-resonant frequency. So don't put more > turns on the choke than the number of meters in a wavelength, > e.g. no more than 20 turns on 20m, no more than 6 turns on > 6m. Backup calculations will be published on my web page. > -- > 73, Cecil http://www.qsl.net/w5dxp 20 Turns is way too much for 20 through to 10. http://www.k1ttt.net/technote/airbalun.html Some actual measurements with a Network Analyzer. It shows 6 turns is enough for 20 through to 10. Article: 227664 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Subject: Re: Rule of Thumb for coax chokes Date: Fri, 4 Aug 2006 05:45:10 +0100 Message-ID: I have just improved and added to the notes to program SELFRES3. The issue date on the first page of operating notes has been changed to 4th August 2006. I suggest you download SELFRES3 again and use it overwrite your old copies. ----- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 227665 of rec.radio.amateur.antenna From: "Will" Subject: Re: Rule of Thumb for coax chokes Date: 3 Aug 2006 23:56:08 -0700 Message-ID: <1154674568.119112.108170@m73g2000cwd.googlegroups.com> References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> That is neet. Now I just got to figure a choke of RG8X at 146mhz to keep the RF from comming back down the outside of the coax cable from the J pole. The VSWR is realy good at 1:1.1, and it talks realy well. What about ferrite beads/chokes over the coax instead of the coil of coax cable? Article: 227666 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> Message-ID: Date: Fri, 04 Aug 2006 11:11:43 GMT Reg Edwards wrote: > Can't you see that the first resonance corresponds to the parallel > resonance of the inductance with its stray capacitance, and is what > you call its 1/2-wave resonance? It may just be semantics. I call the first parallel self- resonant point the *1/4WL* self-resonant point. At its self- resonant frequency, a mobile loading coil is 1/4WL long. I am using that same convention for the coax choke. For instance, my 75m bugcatcher mobile loading coil is self-resonant at ~6.6 MHz. That's the frequency at which it is 1/4 wavelength long and presents a high impedance. At some higher frequency, it is 1/2WL long and presents a low impedance. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227667 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <1154658861.371239.283890@i3g2000cwc.googlegroups.com> Message-ID: <4_FAg.4435$uo6.84@newssvr13.news.prodigy.com> Date: Fri, 04 Aug 2006 11:14:08 GMT Bindy wrote: > Cecil Moore wrote: >> Based on some calculations I did today, I am offering >> an original rule of thumb (as far as I know). Regarding >> a coax choke, when deciding how many turns of coax to put >> on a 2 liter pop bottle at two turns per inch, one needs >> to avoid the self-resonant frequency. So don't put more >> turns on the choke than the number of meters in a wavelength, >> e.g. no more than 20 turns on 20m, no more than 6 turns on >> 6m. Backup calculations will be published on my web page. > > 20 Turns is way too much for 20 through to 10. I didn't say anything about "20 through to 10". Here's what my rule of thumb says: No more than 20 turns on 20m, no more than 10 turns on 10m, and no more than 6 turns on 6m. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227668 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> <1154630456.194673.195900@s13g2000cwa.googlegroups.com> <1154674568.119112.108170@m73g2000cwd.googlegroups.com> Message-ID: Date: Fri, 04 Aug 2006 11:28:32 GMT Will wrote: > That is neet. Now I just got to figure a choke of RG8X at 146mhz to > keep the RF from comming back down the outside of the coax cable from > the J pole. My rule of thumb is for RG-213 wrapped around a 4" dia. 2L pop bottle and thus applies mostly to HF. Using a 2" dia. coil form (pill bottle) with RG8X, my EXCEL program says 2-3 turns is about right for 2m. > What about ferrite beads/chokes over the coax instead of the coil of > coax cable? That works. Just make sure the ferrite is functional at 146 MHz, maybe #67 material. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227669 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <1154658861.371239.283890@i3g2000cwc.googlegroups.com> <4_FAg.4435$uo6.84@newssvr13.news.prodigy.com> Subject: Re: Rule of Thumb for coax chokes Date: Fri, 4 Aug 2006 12:36:23 +0100 Message-ID: "Cecil Moore" wrote in message news:4_FAg.4435$uo6.84@newssvr13.news.prodigy.com... > Bindy wrote: > > Cecil Moore wrote: > >> Based on some calculations I did today, I am offering > >> an original rule of thumb (as far as I know). Regarding > >> a coax choke, when deciding how many turns of coax to put > >> on a 2 liter pop bottle at two turns per inch, one needs > >> to avoid the self-resonant frequency. So don't put more > >> turns on the choke than the number of meters in a wavelength, > >> e.g. no more than 20 turns on 20m, no more than 6 turns on > >> 6m. Backup calculations will be published on my web page. > > > > 20 Turns is way too much for 20 through to 10. > > I didn't say anything about "20 through to 10". Here's what > my rule of thumb says: > > No more than 20 turns on 20m, no more than 10 turns on 10m, > and no more than 6 turns on 6m. ====================================== Cec, Does all the above apply to the diameter of a pop bottle? And what is the diameter over the plastic jacket of the coax? The length of the coil will be N times the jacket diameter, assuming the N turns are close-spaced. Don't forget, mean coil diameter will be pop bottle diameter plus coax jacket diameter. It does make a difference. ----- Reg. Article: 227670 of rec.radio.amateur.antenna From: Al Klein Subject: Re: If you had to use CW to save someone's life, would that person die? Message-ID: <5tf6d2ptdumn4ipooba9f0db0907vtp0q5@4ax.com> References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> Date: Fri, 04 Aug 2006 08:38:58 -0400 On Thu, 03 Aug 2006 15:35:11 GMT, Cecil Moore wrote: >clfe wrote: >> It comes down to - if you want to do ANYTHING - be it do morse code, drive, >> parachuting, whatever - you have to MEMORIZE SOMETHING - to make it happen. >My point exactly! I'm not the one saying that memorizing >is evil. No, you're the one misrepresenting "memorizing answers, as opposed to memorization per se, is wrong" means "memorizing is evil". Article: 227671 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <1154658861.371239.283890@i3g2000cwc.googlegroups.com> <4_FAg.4435$uo6.84@newssvr13.news.prodigy.com> Message-ID: Date: Fri, 04 Aug 2006 12:45:14 GMT Reg Edwards wrote: > Does all the above apply to the diameter of a pop bottle? Yes 4" dia. and 2 turns per inch using RG-213. > And what is the diameter over the plastic jacket of the coax? 0.405" for RG-213, approximately 1/2". > The length of the coil will be N times the jacket diameter, assuming > the N turns are close-spaced. Yes, that's why there are 2 turns per inch for RG-213. > Don't forget, mean coil diameter will be pop bottle diameter plus coax > jacket diameter. It does make a difference. Maybe a 10-20% difference. Doesn't make much difference to a rule of thumb. :-) -- 73, Cecil http://www.qsl.net/w5dxp Article: 227672 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: If you had to use CW to save someone's life, would that person References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <5tf6d2ptdumn4ipooba9f0db0907vtp0q5@4ax.com> Message-ID: Date: Fri, 04 Aug 2006 12:49:46 GMT Al Klein wrote: > No, you're the one misrepresenting "memorizing answers, as opposed to > memorization per se, is wrong" means "memorizing is evil". How the heck can someone know that the ohm is the unit of resistance without memorizing it? How can you possibly develop Ohm's family name from first principles? I memorized the ARRL License Manual in the early 1950's in order to obtain my first two amateur radio licenses. Memorizing license manuals is absolutely nothing new. -- 73, Cecil http://www.qsl.net/w5dxp Article: 227673 of rec.radio.amateur.antenna From: "clfe" References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <5tf6d2ptdumn4ipooba9f0db0907vtp0q5@4ax.com> Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Fri, 4 Aug 2006 08:58:19 -0400 Message-ID: <44d34461$0$2916$ecde5a14@news.coretel.net> "Cecil Moore" wrote in message news:KnHAg.2264$9T3.1510@newssvr25.news.prodigy.net... > Al Klein wrote: >> No, you're the one misrepresenting "memorizing answers, as opposed to >> memorization per se, is wrong" means "memorizing is evil". > > How the heck can someone know that the ohm is the unit > of resistance without memorizing it? How can you possibly > develop Ohm's family name from first principles? I > memorized the ARRL License Manual in the early 1950's > in order to obtain my first two amateur radio licenses. > Memorizing license manuals is absolutely nothing new. > -- > 73, Cecil http://www.qsl.net/w5dxp I "may" be going out on a limb here but I THINK I may have figured out what Al Klein is speaking of - possibly misrepresenting his line of thinking in the scope of things - thus causing the confusion. I THINK his idea of memorization or what he is referring to is as such - lets say you have someone who wants to pass their ham exam. They buy a manual and instead of reading the damned thing to LEARN the ins and outs of ham radio, applicable theory, rules, regulations and so on - they simply try to memorize each answer which is shown as the right answer - merely by A, B, C or D. Some clown I knew, tried this - he didn't take into account that the tests were not always in that order - when it came to the answers. Am I correct Mr. Klein? lou/ka3flu Article: 227674 of rec.radio.amateur.antenna From: "Jerry Martes" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> <1154630456.194673.195900@s13g2000cwa.googlegroups.com> <1154674568.119112.108170@m73g2000cwd.googlegroups.com> Subject: Re: Rule of Thumb for coax chokes Message-ID: Date: Fri, 04 Aug 2006 14:26:36 GMT "Will" wrote in message news:1154674568.119112.108170@m73g2000cwd.googlegroups.com... > That is neet. Now I just got to figure a choke of RG8X at 146mhz to > keep the RF from comming back down the outside of the coax cable from > the J pole. > The VSWR is realy good at 1:1.1, and it talks realy well. > > What about ferrite beads/chokes over the coax instead of the coil of > coax cable? Hi Will I have been using some affordable ferrites for "keeping the RF from the outside of the coax" at about 2 meters. All my crude measurements indicate that the Very affordable ferrite tubes from All Electronics http://www.allelectronics.com/ work OK. I figured the tubes were intended to keep RFI from conducting down the cables inside the *All ferrite tubes*, so I tried them, and they work for me. They have some snap-on models that might have an ID big enough to fit over your RG8X. Jerry Article: 227675 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <1154658861.371239.283890@i3g2000cwc.googlegroups.com> <4_FAg.4435$uo6.84@newssvr13.news.prodigy.com> Subject: Re: Rule of Thumb for coax chokes Date: Fri, 4 Aug 2006 16:33:24 +0100 Message-ID: Cec, Let us know when your rule-of-thumb is available from your website. I'm looking forward to seeing the details. I guess there will be the usual collection of over-meticulous nit-pickers. ---- Reg. Article: 227676 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <1154658861.371239.283890@i3g2000cwc.googlegroups.com> <4_FAg.4435$uo6.84@newssvr13.news.prodigy.com> Message-ID: Date: Fri, 04 Aug 2006 16:10:04 GMT Reg Edwards wrote: > Let us know when your rule-of-thumb is available from your website. > I'm looking forward to seeing the details. It's at http://www.qsl.net/w5dxp/Corum1.xls Can you run EXCEL, Reg, or do you need it in a different form? -- 73, Cecil, http://www.qsl.net/w5dxp Article: 227677 of rec.radio.amateur.antenna From: Michael Coslo Subject: Re: neighborhood antenna restrictions Date: Fri, 04 Aug 2006 12:37:40 -0400 Message-ID: References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <1153962517.218150@www.vif.com> <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <99SdnWP6DKrh9UzZnZ2dnUVZ_vOdnZ2d@adelphia.com> Wayne wrote: > "Bob Agnew" wrote in message > news:RwuAg.346$0F5.150@fed1read04... >>> Same difference. I wouldn't live in one of those deed restricted >>> developments, and I definitely wouldn't live in SoCa. >>> >> I didn't have any choice. I had to take the job here in order to support >> my family. >> Good paying job openings for MSEE's were not all that abundant in 1971. >> > Seems like those were the days when the last engineer leaving Seattle was > supposed to turn off the lights.....I ended up in NJ for a couple of years > during that timeframe. > > Which Exit? - 73 de Mike KB3EIA - Article: 227678 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <1154658861.371239.283890@i3g2000cwc.googlegroups.com> <4_FAg.4435$uo6.84@newssvr13.news.prodigy.com> Subject: Re: Rule of Thumb for coax chokes Date: Fri, 4 Aug 2006 17:41:07 +0100 Message-ID: <7-6dnZ5siOp_5U7ZnZ2dnUVZ8tKdnZ2d@bt.com> Cec, I can't run Excel. I need something which will run just by clicking on it. ---- Reg. ============================== "Cecil Moore" wrote in message news:wjKAg.2295$9T3.256@newssvr25.news.prodigy.net... > Reg Edwards wrote: > > Let us know when your rule-of-thumb is available from your website. > > I'm looking forward to seeing the details. > > It's at http://www.qsl.net/w5dxp/Corum1.xls > > Can you run EXCEL, Reg, or do you need it in a different form? > -- > 73, Cecil, http://www.qsl.net/w5dxp Article: 227679 of rec.radio.amateur.antenna From: "John, N9JG" References: <1153692686.342597.27820@h48g2000cwc.googlegroups.com> <7q8gc29rlrk7j0lbrkttk8arlljkcbc9ot@4ax.com> <12chu7kf24achb5@corp.supernews.com> <96eyg.183010$F_3.61338@newssvr29.news.prodigy.net> Subject: Re: neighborhood antenna restrictions Message-ID: Date: Fri, 04 Aug 2006 18:56:41 GMT The April QST article I liked appeared in about 1973. It was an article on a zero-bandwidth audio filter. The schematic showed a "filter" connected between the hot side of a phone jack to ground, and the bill of materials listed the filter as a precise length of "common copper conductor". I had a Princeton PhD in physics ask me where he could purchase some common copper conductor. He took it fairly well when I pointed out that the article was >from an April issue. "Jim - NN7K" wrote in message news:96eyg.183010$F_3.61338@newssvr29.news.prodigy.net... > > > Dr Shorza Gitchigoomie also wrote about Useing "Negative Resistance" to do > the Contra Polar Energy thing. Funny, I could never get these to work the > way he described them (think was about 14 > at the time)! That was CQ's premier "Engineer"! > Jim NN7K >> >>> Bill Turner wrote: >>> >>>> There was an article in QST about underground antennas. It might have >>>> been an April fool's article but it was so long ago I don't remember >>>> for sure. I was 14 or 15 and anything seemed possible. :-) [snip] Article: 227680 of rec.radio.amateur.antenna From: Al Klein Subject: Re: If you had to use CW to save someone's life, would that person die? Message-ID: References: <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <5tf6d2ptdumn4ipooba9f0db0907vtp0q5@4ax.com> Date: Fri, 04 Aug 2006 15:35:12 -0400 On Fri, 04 Aug 2006 12:49:46 GMT, Cecil Moore wrote: >Al Klein wrote: >> No, you're the one misrepresenting "memorizing answers, as opposed to >> memorization per se, is wrong" means "memorizing is evil". >How the heck can someone know that the ohm is the unit >of resistance without memorizing it? That's exactly what I mean. You're misrepresenting "memorizing that the answer to the question about the resistor with the orange band is 10,000 ohms" is the same as "memorizing the color code". Article: 227681 of rec.radio.amateur.antenna From: Al Klein Subject: Re: If you had to use CW to save someone's life, would that person die? Message-ID: References: <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <5tf6d2ptdumn4ipooba9f0db0907vtp0q5@4ax.com> <44d34461$0$2916$ecde5a14@news.coretel.net> Date: Fri, 04 Aug 2006 15:39:25 -0400 On Fri, 4 Aug 2006 08:58:19 -0400, "clfe" wrote: >I THINK his idea of memorization or what he is referring to is as such - >lets say you have someone who wants to pass their ham exam. They buy a >manual and instead of reading the damned thing to LEARN the ins and outs of >ham radio, applicable theory, rules, regulations and so on - they simply try >to memorize each answer which is shown as the right answer - merely by A, B, >C or D. Some clown I knew, tried this - he didn't take into account that the >tests were not always in that order - when it came to the answers. >Am I correct Mr. Klein? To paraphrase Maxwell Smart, you're thiiiiis close. Substitute "the correct answer to each question" for "A, B ..." and you've got it. Some things have to be memorized - you can't, as Cecil tells us, derive laws from first principles - but there's a difference between "the answer to the question about the oscillator is the .001ufd capacitor" and learning the basics of a Twin-T circuit. Article: 227682 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Fri, 04 Aug 2006 13:45:45 -0700 Message-ID: References: <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> ORIGINAL MESSAGE: On Thu, 03 Aug 2006 14:26:51 GMT, Cecil Moore wrote: >Since memorizing is evil, the Morse code >skill exam should be the first thing to be eliminated. >-- ------------ REPLY SEPARATOR ------------ Second thing. English has to go first. Bill, W6WRT Article: 227683 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Fri, 04 Aug 2006 13:47:40 -0700 Message-ID: <6ic7d2diqkk5go86t8bo86ik3c43t3laco@4ax.com> References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <44d216cb$0$2920$ecde5a14@news.coretel.net> ORIGINAL MESSAGE: On Thu, 3 Aug 2006 11:31:37 -0400, "clfe" wrote: >AND unless that NC tech clarifies it, the unsuspecting >person will go on in ignorance "assuming" ALL hams "know" code. ------------ REPLY SEPARATOR ------------ Well then, cure the ignorance. Wouldn't that be easier than learning the code? Bill, W6WRT Article: 227684 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Fri, 04 Aug 2006 13:55:30 -0700 Message-ID: <0mc7d2di3vfh0q12jevrjdi1al2i7f6k3d@4ax.com> References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> ORIGINAL MESSAGE: On Thu, 03 Aug 2006 11:11:33 -0700, Jim Kelley wrote: >> Yep. I live 30 miles due north of Palm Springs and the jackrabbits >> don't care at all. >> >> Bill, W6WRT > >You're next, Bill. Enjoy it while it lasts! :-) > >ac6xg > ------------ REPLY SEPARATOR ------------ I'm next? You obviously don't realize how large SoCal is! Come visit sometime and I'll take you on roads where you can drive for hours and never see another car or person, not to mention a Homeowner's Association. :-) The county I live in, San Bernardino, is larger than nine of the states. Think about that for a moment. How come we don't have two senators? Bill, W6WRT Article: 227685 of rec.radio.amateur.antenna From: "clfe" References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <44d216cb$0$2920$ecde5a14@news.coretel.net> <6ic7d2diqkk5go86t8bo86ik3c43t3laco@4ax.com> Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Fri, 4 Aug 2006 17:11:56 -0400 Message-ID: <44d3b80f$0$2919$ecde5a14@news.coretel.net> "Bill Turner" wrote in message news:6ic7d2diqkk5go86t8bo86ik3c43t3laco@4ax.com... > ORIGINAL MESSAGE: > > On Thu, 3 Aug 2006 11:31:37 -0400, "clfe" > wrote: > >>AND unless that NC tech clarifies it, the unsuspecting >>person will go on in ignorance "assuming" ALL hams "know" code. > > ------------ REPLY SEPARATOR ------------ > > Well then, cure the ignorance. Wouldn't that be easier than learning > the code? > > Bill, W6WRT I "may" agree with you - in part, but we all know thats not going to happen! It is a matter of human nature. Article: 227686 of rec.radio.amateur.antenna From: "an old freind" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 4 Aug 2006 14:18:12 -0700 Message-ID: <1154726291.953345.94290@h48g2000cwc.googlegroups.com> References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> clfe wrote: > "Bill Turner" wrote in message > news:6ic7d2diqkk5go86t8bo86ik3c43t3laco@4ax.com... > > ORIGINAL MESSAGE: > > > > On Thu, 3 Aug 2006 11:31:37 -0400, "clfe" > > wrote: > > > >>AND unless that NC tech clarifies it, the unsuspecting > >>person will go on in ignorance "assuming" ALL hams "know" code. > > > > ------------ REPLY SEPARATOR ------------ > > > > Well then, cure the ignorance. Wouldn't that be easier than learning > > the code? > > > > Bill, W6WRT > > I "may" agree with you - in part, but we all know thats not going to happen! > It is a matter of human nature. i don't it was pretty for me one day work on one of these bike races the served organizers heard the reapteer CW id asked what it read I said hame were no longer required to be to read them and I could not, time change ignorance fixed Article: 227687 of rec.radio.amateur.antenna From: Jim Kelley Subject: Re: neighborhood antenna restrictions Date: Fri, 04 Aug 2006 15:22:20 -0700 Message-ID: References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <0mc7d2di3vfh0q12jevrjdi1al2i7f6k3d@4ax.com> Bill Turner wrote: > I'm next? Think you're not? Beware the legislators. > You obviously don't realize how large SoCal is! Come visit sometime > and I'll take you on roads where you can drive for hours and never see > another car or person, not to mention a Homeowner's Association. :-) Apparently they even don't have call books there where you are! :-) I've lived here since the middle of last century. Heck, I own property 10 miles down the road from you. > The county I live in, San Bernardino, I guess they must not have mail delivery out there. According to your FCC records, you pick up your mail in Los Angeles. is larger than nine of the > states. None of the other counties wanted any of it. :-) Think about that for a moment. How come we don't have two > senators? We do. And you can have 'em. ac6xg Article: 227688 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: If you had to use CW to save someone's life, would that person die? Date: Fri, 04 Aug 2006 17:26:18 -0700 Message-ID: <77p7d218eepp3gi87gqgr4rvmqs5nobkif@4ax.com> References: <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <44d216cb$0$2920$ecde5a14@news.coretel.net> <6ic7d2diqkk5go86t8bo86ik3c43t3laco@4ax.com> <44d3b80f$0$2919$ecde5a14@news.coretel.net> <1154726291.953345.94290@h48g2000cwc.googlegroups.com> ORIGINAL MESSAGE: On 4 Aug 2006 14:18:12 -0700, "an old freind" wrote: >i don't it was pretty for me one day work on one of these bike races >the served organizers heard the reapteer CW id asked what it read I >said hame were no longer required to be to read them and I could not, >time change ignorance fixed ------------ REPLY SEPARATOR ------------ Text like the above is what comes out when I try to copy CW. Bill, W6WRT 20 WPM Extra, but just barely Article: 227689 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Fri, 04 Aug 2006 17:35:38 -0700 Message-ID: References: <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <0mc7d2di3vfh0q12jevrjdi1al2i7f6k3d@4ax.com> On Fri, 04 Aug 2006 15:22:20 -0700, Jim Kelley wrote: >Apparently they even don't have call books there where you are! :-) >I've lived here since the middle of last century. Heck, I own >property 10 miles down the road from you. Are you talking about Silverado? I haven't the foggiest where it is but I guarantee it isn't ten miles down the road from me. > >I guess they must not have mail delivery out there. According to your >FCC records, you pick up your mail in Los Angeles. Busted call. I have never lived in or picked up mail in Los Angeles. Try again. Bill, W6WRT Article: 227690 of rec.radio.amateur.antenna From: Bill Turner Subject: Re: neighborhood antenna restrictions Date: Fri, 04 Aug 2006 17:44:20 -0700 Message-ID: References: <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <0mc7d2di3vfh0q12jevrjdi1al2i7f6k3d@4ax.com> ORIGINAL MESSAGE: On Fri, 04 Aug 2006 15:22:20 -0700, Jim Kelley wrote: >I've lived here since the middle of last century. ------------ REPLY SEPARATOR ------------ Is Silverado a stealth community? I went to http://www.hometownlocator.com/City/Silverado-California.cfm and the map shows a bunch of towns, but not that one. Actually, that might be good for a ham worried about Homeowners Associations. :-) Bill, W6WRT Article: 227691 of rec.radio.amateur.antenna From: "Harbin Osteen" References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> <44D0D8A2.FECE1660@shaw.ca> Subject: Re: Any info on this type of mobile antenna? Date: Fri, 4 Aug 2006 17:47:31 -0700 Message-ID: Howdy Irv: Nope, not a reflector. I have seen these on several types of German armor, and it seems that this is the way it is used. I'm trying to understand how this type of antenna works, and if it would scale down to VHF. It is mostly seen on German armored scout cars, such as the link below.: http://www.missing-lynx.com/gallery/german/cl232.htm -- SeeYaa:) Harbin Osteen KG6URO !sdohtem noitpyrcne devorppa-tnemnrevog troppus I - "Irv Finkleman" wrote in message news:44D0D8A2.FECE1660@shaw.ca... > Harbin Osteen wrote: >> >> Any info on this type of mobile antenna?: >> http://www.gordon.army.mil/AC/Winter/Winter%2001/images/gerc2veh.jpg >> >> -- >> >> SeeYaa:) Harbin Osteen KG6URO >> >> !sdohtem noitpyrcne devorppa-tnemnrevog troppus I >> >> - > > The ones on the front fenders are cut up rabbit ears. I'm not > sure about the one on top, however it may be some kind of reflector. > > Irv VE6BP > > !oot eM > -- > -------------------------------------- > Visit my HomePage at http://members.shaw.ca/finkirv/index.html > Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm > Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm > -------------------- > Irv Finkleman, > Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP > Calgary, Alberta, Canada Article: 227692 of rec.radio.amateur.antenna Date: Fri, 04 Aug 2006 21:15:32 -0400 From: VOA SWLer Subject: Maryland-DC QSO Party - Aug 12 & 13 Message-ID: For information about the Maryland-DC QSO Party, click on . Hope to work you during the contest. 73! Article: 227693 of rec.radio.amateur.antenna From: "an old friend" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 4 Aug 2006 18:26:02 -0700 Message-ID: <1154741161.913572.107030@m79g2000cwm.googlegroups.com> References: <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> Bill Turner wrote: > ORIGINAL MESSAGE: > > On 4 Aug 2006 14:18:12 -0700, "an old freind" > wrote: > > >i don't it was pretty for me one day work on one of these bike races > >the served organizers heard the reapteer CW id asked what it read I > >said hame were no longer required to be to read them and I could not, > >time change ignorance fixed > > ------------ REPLY SEPARATOR ------------ > > Text like the above is what comes out when I try to copy CW. can you still read it when you do it > > Bill, W6WRT > 20 WPM Extra, but just barely Article: 227694 of rec.radio.amateur.antenna From: "Frank's" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> Subject: Re: Radiating Efficiency Message-ID: Date: Sat, 05 Aug 2006 02:46:10 GMT > The input impedance of 26 radials is NOT equal to all 26 connected in > parallel. There is a non-linear relationship between the number N and > input impedance because they share the same volume of soil at least > when they are short. > > For 26 radials the resonant effects have disappeared which I cannot > explain. Yet attenuation is the same, Zo converges on Zin at > approximately 8 or 10 metres as before. > > You appear to have automated the results. Can you do a large number > of radials, say around 100, from 0.4 to 8.0 metres? > > And can you do a small number of radials such as 6 or 8, from 0.4 to > 8.0 metres? Reg, Here is the analysis of an 8 radial system. All other parameters the same: 0.4 m -- Radial Z = 65.4 - j 58.1 -- Efficiency 11.2% 0.6 m -- Radial Z = 48.7 - j 55.4 0.8 m -- Radial Z = 39.8 - j 29.6 1.0 m -- Radial Z = 34.2 - j 23.5 1.2 m -- Radial Z = 30.2 - j 19.2 1.4 m -- Radial Z = 27.2 - j 16.1 1.6 m -- Radial Z = 24.9 - j 13.7 1.8 m -- Radial Z = 23.0 - j 11.7 -- Efficiency 19.4% 2.0 m -- Radial Z = 21.3 - j 10.0 2.2 m -- Radial Z = 19.9 - j 8.5 2.4 m -- Radial Z = 18.7 - j 7.1 2.6 m -- Radial Z = 17.7 - j 5.9 2.8 m -- Radial Z = 16.7 - j 4.6 3.0 m -- Radial Z = 15.9 - j 3.5 3.2 m -- Radial Z = 15.2 - j 2.3 -- Efficiency 22.4% 3.4 m -- Radial Z = 14.7 - j 1.1 3.6 m -- Radial Z = 14.3 + j 0 3.8 m -- Radial Z = 14.0 + j 1.1 4.0 m -- Radial Z = 13.9 + j 2.2 -- Efficiency 23.2% 4.2 m -- Radial Z = 13.9 + j 3.2 4.4 m -- Radial Z = 14.1 + j 4.2 4.6 m -- Radial Z = 14.4 + j 5.0 4.8 m -- Radial Z = 14.7 + j 5.7 5.0 m -- Radial Z = 15.2 + j 6.3 -- Efficiency 23.0% 5.2 m -- Radial Z = 15.6 + j 6.7 5.4 m -- Radial Z = 16.1 + j 7.1 5.6 m -- Radial Z = 16.5 + j 7.3 5.8 m -- Radial Z = 16.9 + j 7.4 6.0 m -- Radial Z = 17.2 + j 7.5 6.2 m -- Radial Z = 17.5 + j 7.5 -- Efficiency 22.5% 6.4 m -- Radial Z = 17.8 + j 7.5 6.6 m -- Radial Z = 18.0 + j 7.4 6.8 m -- Radial Z = 18.1 + j 7.4 7.0 m -- Radial Z = 18.3 + j 7.4 7.2 m -- Radial Z = 18.4 + j 7.3 7.4 m -- Radial Z = 18.4 + j 7.3 7.6 m -- Radial Z = 18.5 + j 7.2 7.8 m -- Radial Z = 18.6 + j 7.2 8.0 m -- Radial Z = 18.6 + j 7.2 -- Efficiency 22.4% Note that after 4 m the antenna efficiency starts to drop, which is not the case for large numbers of radials. Now I have to figure out the best way to model a 100 radial system. Frank Article: 227695 of rec.radio.amateur.antenna From: "Harbin Osteen" References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> <44D0D8A2.FECE1660@shaw.ca> Subject: Re: Any info on this type of mobile antenna? Date: Fri, 4 Aug 2006 21:56:02 -0700 Message-ID: Howdy again: I found out the info I was looking for on this type of antenna. It is a loop used for NIVS mode of comunication.: High-frequency radio returns to transformation Army in brigade combat teams http://www.gordon.army.mil/AC/Winter/Winter%2001/HFIBCT.htm "Harbin Osteen" wrote in message news:ks-dncfLhPULd07ZnZ2dnUVZ_qmdnZ2d@adelphia.com... > Howdy Irv: > Nope, not a reflector. I have seen these on several types > of German armor, and it seems that this is the way it is used. > I'm trying to understand how this type of antenna works, and > if it would scale down to VHF. It is mostly seen on German > armored scout cars, such as the link below.: > http://www.missing-lynx.com/gallery/german/cl232.htm > > > -- > > SeeYaa:) Harbin Osteen KG6URO > > !sdohtem noitpyrcne devorppa-tnemnrevog troppus I > - > > > > "Irv Finkleman" wrote in message > news:44D0D8A2.FECE1660@shaw.ca... >> Harbin Osteen wrote: >>> >>> Any info on this type of mobile antenna?: >>> http://www.gordon.army.mil/AC/Winter/Winter%2001/images/gerc2veh.jpg >>> >>> -- >>> >>> SeeYaa:) Harbin Osteen KG6URO >>> >>> !sdohtem noitpyrcne devorppa-tnemnrevog troppus I >>> >>> - >> >> The ones on the front fenders are cut up rabbit ears. I'm not >> sure about the one on top, however it may be some kind of reflector. >> >> Irv VE6BP >> >> !oot eM >> -- >> -------------------------------------- >> Visit my HomePage at http://members.shaw.ca/finkirv/index.html >> Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm >> Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm >> -------------------- >> Irv Finkleman, >> Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP >> Calgary, Alberta, Canada > > Article: 227696 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Any info on this type of mobile antenna? Date: Fri, 04 Aug 2006 22:25:11 -0700 Message-ID: <6pa8d2hhk93l678n7tuei578s3ptftblbh@4ax.com> References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> <44D0D8A2.FECE1660@shaw.ca> On Fri, 4 Aug 2006 17:47:31 -0700, "Harbin Osteen" wrote: > Nope, not a reflector. I have seen these on several types >of German armor, and it seems that this is the way it is used. >I'm trying to understand how this type of antenna works, and >if it would scale down to VHF. It is mostly seen on German >armored scout cars, such as the link below.: Hi Harbin, On closer research, it is a loop antenna suited for MF to low HF (as high as 40M). This is from an interesting article in how the US Army has discovered it needs HF comm gear to do the job satellites and VHF repeaters were suppose to do: http://www.gordon.army.mil/AC/Winter/Winter%2001/HFIBCT.htm 73's Richard Clark, KB7QHC Article: 227697 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <44d0ed83$0$35084$4fafbaef@reader4.news.tin.it> <44d0fe0d$0$35074$4fafbaef@reader4.news.tin.it> <1154548645.376883.303310@m73g2000cwd.googlegroups.com> <44d10f83$0$35078$4fafbaef@reader4.news.tin.it> <1154555178.548566.311570@75g2000cwc.googlegroups.com> <44d253d1$0$35079$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Sat, 5 Aug 2006 09:59:28 +0200 Message-ID: <44d44fe0$0$35082$4fafbaef@reader4.news.tin.it> As mentioned earlier, it not being easy to precisely predict whether and = how much the conductive rod would influence the antenna behavior, I = decided to buy a carbon fibre rod measuring 26.2 feet (fully extended). = Its diameter varies from 1 1/8 inch at the base to just 1/16 of inch at = the top. Its weight is just 0.7 lbs! At it stands very straight when you = keep it horizontal. The first test was to determine its DC ohmic resistance. This is a very = difficult test as resistance varies a lot depending on how much you = press the ohmeter leads against the rod. Let us say that, on the 1-inch = diameter tube, putting the ohmeter leads at a 2-inch distance, and very = strongly pressing the leads against the rod, I measured something in the = range of 10 ohm. Then, keeping one lead firm, I slided the other lead = across the rod: resistance was varying between some 10 and 20 ohms, but = there was not a clear correlation between the leads distance and = resistance. Anyway, despite no precise data could be obtained, at least = I understood that the rod resistance is not all negligible and that it = then would probably make little sense to use the rod alone as ground = plane radiator (i.e. without a parallel copper wire). I then laid a bare copper wire (0.1 inch diameter) along the whole rod = (reduced in length to about 23 feet, so as to resonate on the 10 MHz = band) and tightly taped it to the rod at its top, at its bottom and = every about 3 feet. How good were the ohmic contacts between the copper = wire and the rod is however hard to tell. The rod was then erected, standing on an insulator at its bottom. The = coaxial cable center conductor was connected to the copper wire (by the = very bottom of the rod) and its braid to four radials laid on the = ground. In this way the copper wire acts as radiatior, while the rod is = just a passive structure put in contact with the wire every 3 feet.=20 Initial low-power tests at 10.15 MHz showed a very low SWR. Luckily the = antenna length was appropriate. I then applied a carrier at some 1500W and after a couple of minutes or = so I saw the reflected power meter oscillating, until it suddently went = up a lot. I immediately went to inspect the antenna and I found that the rod was = fairly hot. Moreover there were clear signs of sparking between the = copper wire and the rod here and there, and the tape had melted at some = points. It can be concluded that the theory according to which the copper wire = simply bypasses the rod due to its much lower resistance does not seem = to apply. On the other hand I was feeding the wire, not the rod! The explanation could be as follows. The RF current only flows in the = copper wire due to its much lower resistance, and RF voltage then varies = along the wire (maximum at the top, minimum at the base). If we now = consider two points where the rod is taped to the wire (3 feet apart), = there will be significant RF voltage between those two points. Then the = conductive rod, subjected to that high voltage, draws significant RF = current, so dissipating power. Any other comment? An idea would be to spray the rod with a (really) = conductive coating, but does such a varnish exist? 73 Tony I0JX Article: 227698 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <1154575669.483390.122580@h48g2000cwc.googlegroups.com> <1154610189.274197.177730@h48g2000cwc.googlegroups.com> <44d252bd$0$35072$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Sat, 5 Aug 2006 10:00:16 +0200 Message-ID: <44d45010$0$35074$4fafbaef@reader4.news.tin.it> As mentioned earlier, it not being easy to precisely predict whether and = how much the conductive rod would influence the antenna behavior, I = decided to buy a carbon fibre rod measuring 26.2 feet (fully extended). = Its diameter varies from 1 1/8 inch at the base to just 1/16 of inch at = the top. Its weight is just 0.7 lbs! At it stands very straight when you = keep it horizontal. The first test was to determine its DC ohmic resistance. This is a very = difficult test as resistance varies a lot depending on how much you = press the ohmeter leads against the rod. Let us say that, on the 1-inch = diameter tube, putting the ohmeter leads at a 2-inch distance, and very = strongly pressing the leads against the rod, I measured something in the = range of 10 ohm. Then, keeping one lead firm, I slided the other lead = across the rod: resistance was varying between some 10 and 20 ohms, but = there was not a clear correlation between the leads distance and = resistance. Anyway, despite no precise data could be obtained, at least = I understood that the rod resistance is not all negligible and that it = then would probably make little sense to use the rod alone as ground = plane radiator (i.e. without a parallel copper wire). I then laid a bare copper wire (0.1 inch diameter) along the whole rod = (reduced in length to about 23 feet, so as to resonate on the 10 MHz = band) and tightly taped it to the rod at its top, at its bottom and = every about 3 feet. How good were the ohmic contacts between the copper = wire and the rod is however hard to tell. The rod was then erected, standing on an insulator at its bottom. The = coaxial cable center conductor was connected to the copper wire (by the = very bottom of the rod) and its braid to four radials laid on the = ground. In this way the copper wire acts as radiatior, while the rod is = just a passive structure put in contact with the wire every 3 feet.=20 Initial low-power tests at 10.15 MHz showed a very low SWR. Luckily the = antenna length was appropriate. I then applied a carrier at some 1500W and after a couple of minutes or = so I saw the reflected power meter oscillating, until it suddently went = up a lot. I immediately went to inspect the antenna and I found that the rod was = fairly hot. Moreover there were clear signs of sparking between the = copper wire and the rod here and there, and the tape had melted at some = points. It can be concluded that the theory according to which the copper wire = simply bypasses the rod due to its much lower resistance does not seem = to apply. On the other hand I was feeding the wire, not the rod! The explanation could be as follows. The RF current only flows in the = copper wire due to its much lower resistance, and RF voltage then varies = along the wire (maximum at the top, minimum at the base). If we now = consider two points where the rod is taped to the wire (3 feet apart), = there will be significant RF voltage between those two points. Then the = conductive rod, subjected to that high voltage, draws significant RF = current, so dissipating power. Any other comment? An idea would be to spray the rod with a (really) = conductive coating, but does such a varnish exist? 73 Tony I0JX Article: 227699 of rec.radio.amateur.antenna Date: Sat, 05 Aug 2006 05:50:00 -0400 From: Dave Subject: Re: neighborhood antenna restrictions References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <0mc7d2di3vfh0q12jevrjdi1al2i7f6k3d@4ax.com> Message-ID: <1cCdncCk2LFS9EnZnZ2dnUVZ_oKdnZ2d@comcast.com> Bill Turner wrote: > ORIGINAL MESSAGE: > > On Thu, 03 Aug 2006 11:11:33 -0700, Jim Kelley > wrote: > > >>>Yep. I live 30 miles due north of Palm Springs and the jackrabbits >>>don't care at all. >>> >>>Bill, W6WRT >> >>You're next, Bill. Enjoy it while it lasts! :-) >> >>ac6xg >> > > > ------------ REPLY SEPARATOR ------------ > > I'm next? > > You obviously don't realize how large SoCal is! Come visit sometime > and I'll take you on roads where you can drive for hours and never see > another car or person, not to mention a Homeowner's Association. :-) > > The county I live in, San Bernardino, is larger than nine of the > states. Think about that for a moment. How come we don't have two > senators? > > Bill, W6WRT I'm formerly from the People's Socialist Republic of Massachusetts. I know two Senators [ K & K ] that you can have. /s/ DD, W1MCE Article: 227700 of rec.radio.amateur.antenna Date: Sat, 05 Aug 2006 05:54:14 -0400 From: Dave Subject: Re: If you had to use CW to save someone's life, would that person References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <44d216cb$0$2920$ecde5a14@news.coretel.net> <6ic7d2diqkk5go86t8bo86ik3c43t3laco@4ax.com> Message-ID: <1cCdncOk2LFZ90nZnZ2dnUVZ_oKdnZ2d@comcast.com> Bill Turner wrote: > ORIGINAL MESSAGE: > > On Thu, 3 Aug 2006 11:31:37 -0400, "clfe" > wrote: > > >>AND unless that NC tech clarifies it, the unsuspecting >>person will go on in ignorance "assuming" ALL hams "know" code. > > > ------------ REPLY SEPARATOR ------------ > > Well then, cure the ignorance. Wouldn't that be easier than learning > the code? > > Bill, W6WRT Cure the ignorance ... YEP! How? Learn to copy code. Article: 227701 of rec.radio.amateur.antenna Date: Sat, 05 Aug 2006 05:58:55 -0400 From: Dave Subject: Re: If you had to use CW to save someone's life, would that person References: <1153597502.509378.294260@m73g2000cwd.googlegroups.com> <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> Message-ID: Bill Turner wrote: > ORIGINAL MESSAGE: > > On Thu, 03 Aug 2006 14:26:51 GMT, Cecil Moore > wrote: > > >>Since memorizing is evil, the Morse code >>skill exam should be the first thing to be eliminated. >>-- > > > ------------ REPLY SEPARATOR ------------ > > Second thing. English has to go first. > > Bill, W6WRT I'm alomost 69 years old and have forgotten most of what I learned in college. But I still remember what I learned in High School ... how to copy Morse code. I still remember what I learned in grade school ... how to ride a two wheel bicycle. Now, if I could only remember that name of the woman I've live with for the past 43 years ........... Article: 227702 of rec.radio.amateur.antenna From: "Reg Edwards" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <1154575669.483390.122580@h48g2000cwc.googlegroups.com> <1154610189.274197.177730@h48g2000cwc.googlegroups.com> <44d252bd$0$35072$4fafbaef@reader4.news.tin.it> <44d45010$0$35074$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Sat, 5 Aug 2006 11:56:43 +0100 Message-ID: Whether the current flows in the wire or in the rod depends on inductance and inductive reactance. A thin wire has greater inductance and impedance per unit length than a thick rod. ---- Reg. Article: 227703 of rec.radio.amateur.antenna From: ml Subject: sat ant question Message-ID: Date: Sat, 05 Aug 2006 11:38:23 GMT hi thinking about getting into sat's, and have a newbie question i may only be permitted to put up my antennas on a part of the roof that would be blocked by a structure(elevator room) so in 1 compass direction or so to almost straight up i would be blind question: so is their a particular compas headding that is best to loose? Article: 227704 of rec.radio.amateur.antenna Date: Sat, 5 Aug 2006 14:10:55 +0200 From: Dominique Michel Subject: Re: sat ant question Message-ID: <20060805141055.3e228a15@localhost> References: Le Sat, 05 Aug 2006 11:38:23 GMT, ml a écrit : > hi > > thinking about getting into sat's, and have a newbie question > > i may only be permitted to put up my antennas on a part of the roof that > would be blocked by a structure(elevator room) > > so in 1 compass direction or so to almost straight up i would be blind > > question: > > so is their a particular compas headding that is best to loose? It MUST be a direct view from the antenna to the sat. Otherwise is it just to forget it. With analog reception, the antenna can work very well through a glass window, or while directing the antenna on a reflexion (at least if you can afford a high end tuner in this last case), by but with digital reception, even a tiny glass will cause a lot of trouble (some channels will just disappear), because the digital technique use phase multiplexing and the phase of the signal will change in a non linear fashion through the glass or on a reflexion. Dominique Article: 227705 of rec.radio.amateur.antenna From: "neok" <5b4az@qsl.net> Subject: Frequency discriminator algorithms? Date: 5 Aug 2006 06:17:44 -0700 Message-ID: <1154783864.581373.12840@b28g2000cwb.googlegroups.com> Hi all, I had been searching the 'net for simple digital frequency discriminator algorithms (fm detection, eg for SSTV etc) but have not really found any suitable info. In the mean time though, I figured out what I think is a simple solution to this problem and tried it, using my computer's sound system to digitize a sinewave signal from my FT847 rig (tuned to a MW BC station in CW mode and using the narrowest filters). The results were mixed, with an accuracy of about 1% in many readings but with a small portion of them having large errors > 50%. The errors seemed to be spaced at 1/4 of an audio cycle and near peaks and zero's. But before I speculate on possible causes, I would like to take the liberty to describe this algorithm so that experienced DSP boffins might first judge the viability and/or correctnes of it. In a stream of digitized samples of a sine wave, the value s of a sample is given by s = V * sin(F) where V is the peak amplitude and F the phase of the sine wave at the moment the sample was taken. If we take three consecutive samples, s0, s1, s2, we can form the following set of simultaneous equations (by expanding sin(F+dF) & sin(F-dF)). 1. s0 = V*sin(F-dF) = V*{sin(F)*cos(dF)-cos(F)*sin(dF)} 2. s1 = V*sin(F) 3. s2 = V*sin(F+df) = V*{sin(F)*cos(dF)+cos(F)*sin(dF)} where dF is the phase difference between successive samples. By adding 1. and 3. we have: 4. s0+s2 = V*2*sin(F)*cos(dF) By substituting sin(F) from 2. we have: 5. s0+s2 = V*2*(s1/V)*cos(dF) So finally solving 5. for dF we have: 6. dF = arc cos{(s0+s2)/(2*s1)} The frequency f of the sampled signal can then be estimated by: 7. f = (df/2pi)*S or f = S*arc cos{(s0+s2)/(2*s1)}/2pi (2pi=2*pi) I tried this formula by feeding it with calculated samples and it worked fine. In practice, the expected problems I had were division by zero when s1 = 0 and failure of the acos() C function when (s0+s2)/2s1 > 1. But there were inaccuracies in he results as I mentioned near the peaks and zeros since it seems errors in sampling by the dsp distorted the relationship between consecutive samples. I am using Linux and an AC97 type on-board sound system and I already know there are some bugs in the ALSA (the Linux sound systems project) drivers. This is especially obvious when sampling at a non-native DSP rate (other than 48 Khz / 16-bit linear) where the sound driver has to resample the output. I would be greatful for any input on the "legitimacy" of the above derived formula and/or its weak points, so that I can furher study the output of the DSP for possible errors (not very easy ;-)). My apologies for a longish and/or possibly boring article! 73's de "Nick" 5B4AZ http://5b4az.mattsnetwork.co.uk/ Article: 227706 of rec.radio.amateur.antenna From: "neok" <5b4az@qsl.net> Subject: Re: Frequency discriminator algorithms? Date: 5 Aug 2006 06:21:09 -0700 Message-ID: <1154784069.607507.190990@i3g2000cwc.googlegroups.com> References: <1154783864.581373.12840@b28g2000cwb.googlegroups.com> neok wrote: > Hi all, > > I had been searching the 'net for simple digital frequency > discriminator Very sorry guys, posted to wrong group :-( Article: 227707 of rec.radio.amateur.antenna From: Felix Subject: Re: RoomCap Antenna Date: Sat, 5 Aug 2006 09:42:17 +0000 Message-ID: References: <85vg52t9207ouotls9esq04ple5f3gc584@4ax.com> <126f94r9bqkac5a@corp.supernews.com> NEW: RoomCap 160 m Antenna 4th August 2006 I am glad to announce, that the 160 m version is ready, and has been tested successfully. This constitutes a new milestone in antenna technology! The radiator measures only 2% of the wavelength and works equally well as a 36 m longwire. The length of the radiator is 320 cm, and the test antenna was installed on my car. Within a few seconds the SWR is set to 1.0 in the full band from 1.8 to 2.0 MHz, simply by pressing a botton. The last 4 nights I could test and compare this new antenne, and it was a real pleasure. However, one must be aware that the topband 160 m is a night band. Band opening is about at 22h, something for night fans. The comparison was against a 36 m longwire, perfectly matched, 9 m above ground in free environment. Both station were operating with the same power, at the same location (within 300 m). (Thank you Sergio, HB9BXS for your preseverance!) The remote stations gave the following reports, always after a couple of short changeovers between our 2 stations: DJ5MX (Böblingen near Stuttgart) QRB = 170 km - Roomcap is 1 S-point stronger DJ1HS (Lauterhofen nr. Nuernberg) QRB = 360 km - both stations have the same signal strength DJ8YP (Sigmaringen) QRB = 140 km - Roomcap about 3 db weaker DD1IW (nr. Muenchen) QRB = 315 km - both stations are about equal G3IMX (Isle of Wight) QRB = 715 km - Roomcap is 6 to 10 db stronger G0RRM (Lichfield) QRB = 920 km - Roomcap 1/2 S-point weaker G3URM (Staffordshire) QRB = 940 km - Roomcap about 1 S-point stronger + many other stations, confirming the same result. The update for the owners of the construction guide is ready in about 10 days. 73s Felix HB9ABX. -- Felix Article: 227708 of rec.radio.amateur.antenna From: "n3ox.dan@gmail.com" Subject: Re: Question on carbon fibre fishing rod Date: 5 Aug 2006 08:11:18 -0700 Message-ID: <1154790677.995708.44390@n13g2000cwa.googlegroups.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> Tony, >From an EZNEC model with essentially the situation you described: Wire numbers 2 and 5 are both 7.9m high, frequency 10MHz, fed against a radial system in free space. Wire number 2 is 25.4mm diameter, 21 segments, a 10 ohm load in each segment, total "rod resistance" 210 ohms + negligable copper loss. The wire centers are 7cm apart. Wire number 5 is 2mm diameter copper. Wires 2 and 5 are shorted together top and bottom (no contact along the length, but maybe we can see why you had arcing) As you can see below, the currents in the two "wires" with the top and bottom shorted are not in phase. Moreover, the current in the rod (Wire No. 2) is quite appreciable, almost 2/3 that of the wire. Wire No. 2: Segment Conn Magnitude (A.) Phase (Deg.) te1 W4E1 .39744 -167.9 2 .40049 -168.9 3 .39918 -169.3 4 .39463 -169.2 5 .38725 -168.8 6 .3773 -168.1 7 .36499 -166.9 8 .35056 -165.4 9 .33425 -163.5 10 .31635 -161.0 11 .29723 -157.9 12 .27734 -154.0 13 .25727 -149.2 14 .23781 -143.2 15 .22002 -135.8 16 .20528 -126.8 17 .19529 -116.1 18 .19188 -104.1 19 .19661 -91.39 20 .21058 -78.89 21 W3E1 .23611 -66.69 Wire No. 5: Segment Conn Magnitude (A.) Phase (Deg.) 1 W6E1 .64698 170.23 2 .66204 169.08 3 .67227 168.00 4 .67834 166.94 5 .68045 165.86 6 .67871 164.76 7 .6732 163.63 8 .66403 162.44 9 .6513 161.18 10 .63513 159.83 11 .61567 158.39 12 .59307 156.82 13 .56752 155.11 14 .53922 153.20 15 .50842 151.06 16 .47537 148.63 17 .44036 145.82 18 .40374 142.51 19 .36589 138.50 20 .32725 133.51 21 W3E2 .28776 126.90 So how's the loss? Well, here's the table of load data: Frequency = 10 MHz Load 1 Voltage = 14.71 V. at -167.86 deg. Current = 1.471 A. at -167.86 deg. Impedance = 10 + J 0 ohms Power = 21.62 watts Load 2 Voltage = 14.82 V. at -168.9 deg. Current = 1.482 A. at -168.9 deg. Impedance = 10 + J 0 ohms Power = 21.96 watts Load 3 Voltage = 14.77 V. at -169.29 deg. Current = 1.477 A. at -169.29 deg. Impedance = 10 + J 0 ohms Power = 21.81 watts Load 4 Voltage = 14.6 V. at -169.24 deg. Current = 1.46 A. at -169.24 deg. Impedance = 10 + J 0 ohms Power = 21.32 watts Load 5 Voltage = 14.33 V. at -168.83 deg. Current = 1.433 A. at -168.83 deg. Impedance = 10 + J 0 ohms Power = 20.53 watts Load 6 Voltage = 13.96 V. at -168.07 deg. Current = 1.396 A. at -168.07 deg. Impedance = 10 + J 0 ohms Power = 19.49 watts Load 7 Voltage = 13.5 V. at -166.95 deg. Current = 1.35 A. at -166.95 deg. Impedance = 10 + J 0 ohms Power = 18.24 watts Load 8 Voltage = 12.97 V. at -165.43 deg. Current = 1.297 A. at -165.43 deg. Impedance = 10 + J 0 ohms Power = 16.82 watts Load 9 Voltage = 12.37 V. at -163.46 deg. Current = 1.237 A. at -163.46 deg. Impedance = 10 + J 0 ohms Power = 15.29 watts Load 10 Voltage = 11.7 V. at -160.97 deg. Current = 1.17 A. at -160.97 deg. Impedance = 10 + J 0 ohms Power = 13.7 watts Load 11 Voltage = 11 V. at -157.86 deg. Current = 1.1 A. at -157.86 deg. Impedance = 10 + J 0 ohms Power = 12.09 watts Load 12 Voltage = 10.26 V. at -153.99 deg. Current = 1.026 A. at -153.99 deg. Impedance = 10 + J 0 ohms Power = 10.53 watts Load 13 Voltage = 9.519 V. at -149.17 deg. Current = 0.9519 A. at -149.17 deg. Impedance = 10 + J 0 ohms Power = 9.061 watts Load 14 Voltage = 8.799 V. at -143.19 deg. Current = 0.8799 A. at -143.19 deg. Impedance = 10 + J 0 ohms Power = 7.742 watts Load 15 Voltage = 8.141 V. at -135.8 deg. Current = 0.8141 A. at -135.8 deg. Impedance = 10 + J 0 ohms Power = 6.627 watts Load 16 Voltage = 7.595 V. at -126.79 deg. Current = 0.7595 A. at -126.79 deg. Impedance = 10 + J 0 ohms Power = 5.769 watts Load 17 Voltage = 7.226 V. at -116.11 deg. Current = 0.7226 A. at -116.11 deg. Impedance = 10 + J 0 ohms Power = 5.221 watts Load 18 Voltage = 7.099 V. at -104.08 deg. Current = 0.7099 A. at -104.08 deg. Impedance = 10 + J 0 ohms Power = 5.04 watts Load 19 Voltage = 7.274 V. at -91.39 deg. Current = 0.7274 A. at -91.39 deg. Impedance = 10 + J 0 ohms Power = 5.292 watts Load 20 Voltage = 7.791 V. at -78.88 deg. Current = 0.7791 A. at -78.88 deg. Impedance = 10 + J 0 ohms Power = 6.071 watts Load 21 Voltage = 8.736 V. at -66.69 deg. Current = 0.8736 A. at -66.69 deg. Impedance = 10 + J 0 ohms Power = 7.632 watts Total applied power = 1535 watts Total load power = 271.9 watts Total load loss = 0.846 dB The situation is VERY much improved by simply removing the top and bottom shorting wires (this changes the base impedance very much, by the way. I adjusted the source to still give ~1500 watts applied) Total applied power = 1576 watts Total load power = 30.53 watts Total load loss = 0.085 dB The current in the two wires isn't in phase either, but the average magnitude of the current in the rod is more than a factor of ten below the average magnitude of current in the wire. So, space the wire a couple of inches out from the rod with insulators and you should be fine, except, as Reg said before, where the rod is 1/2 wavelength long. If you still get heating, I suppose you'll just have to use the rod as a center support for an inverted-vee antenna or something! The arcing is coming from the fact that the currents are out-of-phase by some amount (40 degrees) in the two conductors... and so are the voltages... you get a potential difference between a point on the wire and the corresponding point on the rod. I doubt it's sufficient to jump any distance air gap, it's more that the carbon can't take the current that wants to flow between the rod and wire and is burning, but that's just a guess, and you know how good my guess was originally. Dan Article: 227709 of rec.radio.amateur.antenna Date: Sat, 5 Aug 2006 17:18:48 +0200 From: Dominique Michel Subject: Spreadsheet for Yagi-Uda array of loops Message-ID: <20060805171848.3a8f7cf6@localhost> Hi all, I have done a spreadsheet for the calculation of Yagi-Uda array of loops. You can get it on internet at http://home.citycable.ch/monde-meilleur/index.html Sorry it is in french, a direct link to the page where the spreadsheet reside is: http://home.citycable.ch/monde-meilleur/antennes/antennes1.html It is 2 versions, the original one for gnumeric at http://home.citycable.ch/monde-meilleur/antennes/Antenne%20multicadres.gnumeric and another one for excel at http://home.citycable.ch/monde-meilleur/antennes/Antenne%20multicadre.xls I have tested the excel version only with openoffice (I use linux at home) and it worked. I have done a TV RX antenna on 487.25 MHz with just a few wood stick and some coaxial cable. It took me 2 hours of job, and I was able to receive with the color a channel I was just able to receive in black and white and a lot of snow with the biggest Wisi UHF antenna. Such an antenna can outperform any commercial antenna. It will just become bigger as you get down in frequency. As example, a five elements 27MHz will do 9.5 meter length for a diameter of the active element of 3,89 meters. Any comments are welcome. I will appreciate very much If someone can take a look on my English and correct it. Just drop me a word or two. Dominique Article: 227710 of rec.radio.amateur.antenna From: "Jerry Martes" References: Subject: Re: sat ant question Message-ID: Date: Sat, 05 Aug 2006 15:22:31 GMT "ml" wrote in message news:m-A452EA.07383705082006@news.verizon.net... > hi > > thinking about getting into sat's, and have a newbie question > > i may only be permitted to put up my antennas on a part of the roof that > would be blocked by a structure(elevator room) > > so in 1 compass direction or so to almost straight up i would be blind > > question: > > so is their a particular compas headding that is best to loose? Hi ml Do you intend to work AMSAT polar orbiting satellites? Is your antenna stearable? What frequency? Jerry Article: 227711 of rec.radio.amateur.antenna From: Bob Subject: Re: sat ant question References: <20060805141055.3e228a15@localhost> Message-ID: Date: Sat, 05 Aug 2006 15:33:07 GMT Are you asking about amateur satellite operation or TV reception via satellites? Although Dominique’s explanation of digital satellite signals passing through glass may be explained on paper, it has no merit in actual use. Some glass has attenuation at C/Ku frequencies but this purely shows up as signal reduction with associated loss of C/N, BER, etc in digital systems. Analog and digital satellite reception are affected the same. Bob Dominique Michel wrote: > Le Sat, 05 Aug 2006 11:38:23 GMT, > ml a écrit : > >> hi >> >> thinking about getting into sat's, and have a newbie question >> >> i may only be permitted to put up my antennas on a part of the roof that >> would be blocked by a structure(elevator room) >> >> so in 1 compass direction or so to almost straight up i would be blind >> >> question: >> >> so is their a particular compas headding that is best to loose? > > It MUST be a direct view from the antenna to the sat. Otherwise is it > just to forget it. With analog reception, the antenna can work very > well through a glass window, or while directing the antenna on a > reflexion (at least if you can afford a high end tuner in this last case), > by but with digital reception, even a tiny glass will cause a > lot of trouble (some channels will just disappear), because the digital technique use phase multiplexing > and the phase of the signal will change in a non linear fashion through > the glass or on a reflexion. > > Dominique Article: 227712 of rec.radio.amateur.antenna Date: Sat, 05 Aug 2006 12:06:42 -0400 From: John Popelish Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <3bCdnRPeEcZBnkzZRVnysw@bt.com> <4h8Ag.521$%j7.331@newssvr29.news.prodigy.net> <1154630456.194673.195900@s13g2000cwa.googlegroups.com> <1154674568.119112.108170@m73g2000cwd.googlegroups.com> Message-ID: Will wrote: > That is neet. Now I just got to figure a choke of RG8X at 146mhz to > keep the RF from comming back down the outside of the coax cable from > the J pole. > The VSWR is realy good at 1:1.1, and it talks realy well. > > What about ferrite beads/chokes over the coax instead of the coil of > coax cable? Digikey carries a pretty broad line of Steward long form ferrite bead cores. You can check the specifications at http://www.steward.com/ For instance, core HFB143064-300 has an impedance of about 180 ohms at 146 MHz. Type HF is their highest frequency material. Core 28B0562-200 (same size in the lower frequency, 28 material) produces an impedance of about 360 ohms per core. I think both of these would fit over RG8X and are about an inch and an eighth long. Article: 227713 of rec.radio.amateur.antenna From: Cecil Moore Subject: Re: Rule of Thumb for coax chokes References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> <1154658861.371239.283890@i3g2000cwc.googlegroups.com> <4_FAg.4435$uo6.84@newssvr13.news.prodigy.com> <7-6dnZ5siOp_5U7ZnZ2dnUVZ8tKdnZ2d@bt.com> Message-ID: Date: Sat, 05 Aug 2006 16:34:34 GMT Reg Edwards wrote: > Cec, I can't run Excel. > I need something which will run just by clicking on it. Reg, did you get the BASIC program I sent to you? If not, please send me an email so I can reply. -- 73, Cecil, W5DXP Article: 227714 of rec.radio.amateur.antenna Date: Sat, 5 Aug 2006 19:21:58 +0200 From: Dominique Michel Subject: Re: sat ant question Message-ID: <20060805192158.3dcc97f1@localhost> References: Le Sat, 05 Aug 2006 15:33:07 GMT, Bob a écrit : > Are you asking about amateur satellite operation or TV reception via > satellites? Although Dominique’s explanation of digital satellite > signals passing through glass may be explained on paper, it has no merit > in actual use. Some glass has attenuation at C/Ku frequencies but this > purely shows up as signal reduction with associated loss of C/N, BER, > etc in digital systems. Analog and digital satellite reception are > affected the same. > Bob > What I say here is based on personal experience. And it is for TV reception that use phase multiplexing in order to send many different channels on the same frequency. The signal going through a glass is affected in a way that do impossible to receive some channels. A bigger parabol will change nothing, it is just to remove the glass to get all the channels. You get exactly the same effect if the shape of the parabol is not perfect (as it can append after a hazard under transportation), it will work just fine for analog reception but with a digital tuner, some channels will work when others will not. It is just to change the parabol to get all the channels. Sometime, the defect with the shape of the parabol is so little as you see nothing with the eyes, but you change it against another one from the same model and it just work. I installed hundreds of parabol antenna, and it was never a problem with a wholesaler or a manufacturer to change a defective parabol, they know this problem very well. Dominique > > Dominique Michel wrote: > > Le Sat, 05 Aug 2006 11:38:23 GMT, > > ml a écrit : > > > >> hi > >> > >> thinking about getting into sat's, and have a newbie question > >> > >> i may only be permitted to put up my antennas on a part of the roof that > >> would be blocked by a structure(elevator room) > >> > >> so in 1 compass direction or so to almost straight up i would be blind > >> > >> question: > >> > >> so is their a particular compas headding that is best to loose? > > > > It MUST be a direct view from the antenna to the sat. Otherwise is it > > just to forget it. With analog reception, the antenna can work very > > well through a glass window, or while directing the antenna on a > > reflexion (at least if you can afford a high end tuner in this last case), > > by but with digital reception, even a tiny glass will cause a > > lot of trouble (some channels will just disappear), because the digital technique use phase multiplexing > > and the phase of the signal will change in a non linear fashion through > > the glass or on a reflexion. > > > > Dominique Article: 227715 of rec.radio.amateur.antenna Date: Sat, 5 Aug 2006 19:30:28 +0200 From: Dominique Michel Subject: Re: Spreadsheet for Yagi-Uda array of loops Message-ID: <20060805193028.51e06624@localhost> References: <20060805171848.3a8f7cf6@localhost> Le Sat, 5 Aug 2006 17:18:48 +0200, Dominique Michel a écrit : > Hi all, > > I have done a spreadsheet for the calculation of Yagi-Uda array of > loops. You can get it on internet at > http://home.citycable.ch/monde-meilleur/index.html > > Sorry it is in french, a direct link to the page where the spreadsheet reside is: > http://home.citycable.ch/monde-meilleur/antennes/antennes1.html > > It is 2 versions, the original one for gnumeric at > http://home.citycable.ch/monde-meilleur/antennes/Antenne%20multicadres.gnumeric > and another one for excel at > http://home.citycable.ch/monde-meilleur/antennes/Antenne%20multicadre.xls > > I have tested the excel version only with openoffice (I use linux at home) and it worked. The website is in French, but the spreadsheet is both in French and English. Dominique > > I have done a TV RX antenna on 487.25 MHz with just a few wood stick and some coaxial cable. It took me 2 hours of job, and I was able to receive with the color a channel I was just able to receive in black and white and a lot of snow with the biggest Wisi UHF antenna. > > Such an antenna can outperform any commercial antenna. It will just become bigger as you get down in frequency. As example, a five elements 27MHz will do 9.5 meter length for a diameter of the active element of 3,89 meters. > > Any comments are welcome. > I will appreciate very much If someone can take a look on my English and correct it. Just drop me a word or two. > > Dominique Article: 227716 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1bOdnTnoDO8PslzZRVnyuA@bt.com> <4jqxg.170368$771.62308@edtnps89> <_FCxg.133334$A8.100770@clgrps12> <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> Subject: Re: Radiating Efficiency Date: Sat, 5 Aug 2006 19:11:17 +0100 Message-ID: > Reg, > > Here is the analysis of an 8 radial system. All other parameters > the same: > > 0.4 m -- Radial Z = 65.4 - j 58.1 -- Efficiency 11.2% > 0.6 m -- Radial Z = 48.7 - j 55.4 > 0.8 m -- Radial Z = 39.8 - j 29.6 > 1.0 m -- Radial Z = 34.2 - j 23.5 > 1.2 m -- Radial Z = 30.2 - j 19.2 > 1.4 m -- Radial Z = 27.2 - j 16.1 > 1.6 m -- Radial Z = 24.9 - j 13.7 > 1.8 m -- Radial Z = 23.0 - j 11.7 -- Efficiency 19.4% > 2.0 m -- Radial Z = 21.3 - j 10.0 > 2.2 m -- Radial Z = 19.9 - j 8.5 > 2.4 m -- Radial Z = 18.7 - j 7.1 > 2.6 m -- Radial Z = 17.7 - j 5.9 > 2.8 m -- Radial Z = 16.7 - j 4.6 > 3.0 m -- Radial Z = 15.9 - j 3.5 > 3.2 m -- Radial Z = 15.2 - j 2.3 -- Efficiency 22.4% > 3.4 m -- Radial Z = 14.7 - j 1.1 > 3.6 m -- Radial Z = 14.3 + j 0 > 3.8 m -- Radial Z = 14.0 + j 1.1 > 4.0 m -- Radial Z = 13.9 + j 2.2 -- Efficiency 23.2% > 4.2 m -- Radial Z = 13.9 + j 3.2 > 4.4 m -- Radial Z = 14.1 + j 4.2 > 4.6 m -- Radial Z = 14.4 + j 5.0 > 4.8 m -- Radial Z = 14.7 + j 5.7 > 5.0 m -- Radial Z = 15.2 + j 6.3 -- Efficiency 23.0% > 5.2 m -- Radial Z = 15.6 + j 6.7 > 5.4 m -- Radial Z = 16.1 + j 7.1 > 5.6 m -- Radial Z = 16.5 + j 7.3 > 5.8 m -- Radial Z = 16.9 + j 7.4 > 6.0 m -- Radial Z = 17.2 + j 7.5 > 6.2 m -- Radial Z = 17.5 + j 7.5 -- Efficiency 22.5% > 6.4 m -- Radial Z = 17.8 + j 7.5 > 6.6 m -- Radial Z = 18.0 + j 7.4 > 6.8 m -- Radial Z = 18.1 + j 7.4 > 7.0 m -- Radial Z = 18.3 + j 7.4 > 7.2 m -- Radial Z = 18.4 + j 7.3 > 7.4 m -- Radial Z = 18.4 + j 7.3 > 7.6 m -- Radial Z = 18.5 + j 7.2 > 7.8 m -- Radial Z = 18.6 + j 7.2 > 8.0 m -- Radial Z = 18.6 + j 7.2 -- Efficiency 22.4% > > Note that after 4 m the antenna efficiency starts to drop, > which is not the case for large numbers of radials. > > Now I have to figure out the best way to model a 100 > radial system. > > Frank ===================================================== Frank, Thank you very much for the results on 8 radials. As expected, it seems that for small numbers of radials the resonance effects are begining to appear again. I have ideas as to why this should happen. It's to do with the geometry of the system and the fact that the ends of the radials are not terminated with true open-circuits when calculating input impedance. ( As is assumed by program Radial3.) I look forward to receiving results for 100 or more radials which may allow me to improve, in the mathematical model, the function of N which describes the system's input impedance in terms of the number N of radials. ---------------------------------------------------------------------- ----------------------- But, let's face it, a good understanding of what's going on under the soil surface, without investigating input impedance at say 25 MHs, and without investigating input imedance at soil resistivities of say 2000 ohm-metres, will be known only crudely. Is it all worth the trouble? After all, we already know enough quite enough about radial systems at HF to design one which will work good enough, performance-wise, to keep anybody happy. ( BL&E's work, as good as it may be, does not apply at HF.) Just lay one or two dozen radials, in ordinary soils, with lengths equal to about half antenna height. Which is a good enough rule-of-thumb for anybody who doesn't expect to win contests because he has the advantage of 0.05 S-units. And extremely few people know what their local soil resistivity is within +/- 40 percent. It's largely guesswork! But please keep up the good work with NEC4 in which I have great confidence. ---- Reg, G4FGQ Article: 227717 of rec.radio.amateur.antenna From: You Subject: Re: neighborhood antenna restrictions References: <2e0ca$44c9674c$8b370cf3$23161@ALLTEL.NET> <43ivc2dimh39i9c79uus1a1thseoj48ke8@4ax.com> <0mc7d2di3vfh0q12jevrjdi1al2i7f6k3d@4ax.com> Message-ID: Date: Sat, 05 Aug 2006 19:10:37 GMT In article , Jim Kelley wrote: > Bill Turner wrote: > > I'm next? > > Think you're not? Beware the legislators. > > > You obviously don't realize how large SoCal is! Come visit sometime > > and I'll take you on roads where you can drive for hours and never see > > another car or person, not to mention a Homeowner's Association. :-) > > Apparently they even don't have call books there where you are! :-) > I've lived here since the middle of last century. Heck, I own > property 10 miles down the road from you. > > > The county I live in, San Bernardino, > > I guess they must not have mail delivery out there. According to your > FCC records, you pick up your mail in Los Angeles. > > is larger than nine of the > > states. > > None of the other counties wanted any of it. :-) > > Think about that for a moment. How come we don't have two > > senators? > > We do. And you can have 'em. > > ac6xg > We have a saying, up here in Alaska, that we use on Texans that come up here. "Shut the f--k up, or we will cut Alaska in half, and Texas will the the third largest state." Goes five times for Kalifornia.... Article: 227718 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Radiating Efficiency Date: Sat, 05 Aug 2006 12:20:17 -0700 Message-ID: <37r9d212pojknc4gifpd1iro0d7h8n8v1i@4ax.com> References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> On Sat, 5 Aug 2006 19:11:17 +0100, "Reg Edwards" wrote: >Thank you very much for the results on 8 radials. > >As expected, it seems that for small numbers of radials the resonance >effects are begining to appear again. > >I have ideas as to why this should happen. Hi Reggie, You "should" if you had read Brown, Lewis, and Epstein. They discussed this nearly 70 years ago. Radial3 appears to miss that mark by various amounts ranging from 6 to 60dB. >It's to do with the geometry of the system Duh. And the problem you injected in that you abstract one wire to many. >and the fact that the ends of the radials are >not terminated with true open-circuits when calculating input >impedance. ( As is assumed by program Radial3.) Given Hassan's and other's reports of the outrageous departures between Radial3 and BLE/NEC4 (with your concurrence): >But please keep up the good work with NEC4 in which I have great >confidence. there are at least two of us who find your contradictions would warrant another fling of chalk off your noggin from Lord Kelvin. 73's Richard Clark, KB7QHC Article: 227719 of rec.radio.amateur.antenna From: "an_old_friend" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 5 Aug 2006 12:33:21 -0700 Message-ID: <1154806401.369014.158580@i3g2000cwc.googlegroups.com> References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> Slow Code wrote: > "an old freind" wrote in > news:1154726291.953345.94290@h48g2000cwc.googlegroups.com: > > > > > It's hard to figure out what you're actually trying to say sometimes Mark, > but what it looks like you were trying to convey to the race organizer is > that you're retarded. never hard to understand you want Ham radio to die if can't retreat into the past but then if you got what you wanted Ham radio would truly be without a future > > Sc Article: 227720 of rec.radio.amateur.antenna From: "Bob Agnew" References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> <44D0D8A2.FECE1660@shaw.ca> <6pa8d2hhk93l678n7tuei578s3ptftblbh@4ax.com> Subject: Re: Any info on this type of mobile antenna? Message-ID: Date: Sat, 5 Aug 2006 14:04:33 -0700 Well there goes my theory that it was a roll cage ;=}} "Richard Clark" wrote in message news:6pa8d2hhk93l678n7tuei578s3ptftblbh@4ax.com... > On Fri, 4 Aug 2006 17:47:31 -0700, "Harbin Osteen" > wrote: > >> Nope, not a reflector. I have seen these on several types >>of German armor, and it seems that this is the way it is used. >>I'm trying to understand how this type of antenna works, and >>if it would scale down to VHF. It is mostly seen on German >>armored scout cars, such as the link below.: > > Hi Harbin, > > On closer research, it is a loop antenna suited for MF to low HF (as > high as 40M). > > This is from an interesting article in how the US Army has discovered > it needs HF comm gear to do the job satellites and VHF repeaters were > suppose to do: > http://www.gordon.army.mil/AC/Winter/Winter%2001/HFIBCT.htm > > 73's > Richard Clark, KB7QHC Article: 227721 of rec.radio.amateur.antenna From: Bob Subject: Re: sat ant question References: <20060805141055.3e228a15@localhost> <20060805192158.3dcc97f1@localhost> Message-ID: <4Y7Bg.4475$gY6.477@newssvr11.news.prodigy.com> Date: Sat, 05 Aug 2006 21:20:00 GMT Dominique, I am also speaking from personal and professional experience with Ku QPSK MCPC systems. Signal loss through the glass in dB correlates with the same decrease in Eb/No in digital systems. I am curious what your location is and what systems you have worked with. Bob Dominique Michel wrote: > Le Sat, 05 Aug 2006 15:33:07 GMT, > Bob a écrit : > >> Are you asking about amateur satellite operation or TV reception via >> satellites? Although Dominique’s explanation of digital satellite >> signals passing through glass may be explained on paper, it has no merit >> in actual use. Some glass has attenuation at C/Ku frequencies but this >> purely shows up as signal reduction with associated loss of C/N, BER, >> etc in digital systems. Analog and digital satellite reception are >> affected the same. >> Bob >> > > What I say here is based on personal experience. And it is for TV reception that use phase multiplexing in order to send many different channels on the same frequency. The signal going through a glass is affected in a way that do impossible to receive some channels. A bigger parabol will change nothing, it is just to remove the glass to get all the channels. > > You get exactly the same effect if the shape of the parabol is not > perfect (as it can append after a hazard under transportation), it will > work just fine for analog reception but with a digital tuner, some > channels will work when others will not. It is just to change the > parabol to get all the channels. Sometime, the defect with the shape of > the parabol is so little as you see nothing with the eyes, but you > change it against another one from the same model and it just work. I > installed hundreds of parabol antenna, and it was never a problem with > a wholesaler or a manufacturer to change a defective parabol, they know this problem very well. > > Dominique > >> Dominique Michel wrote: >>> Le Sat, 05 Aug 2006 11:38:23 GMT, >>> ml a écrit : >>> >>>> hi >>>> >>>> thinking about getting into sat's, and have a newbie question >>>> >>>> i may only be permitted to put up my antennas on a part of the roof that >>>> would be blocked by a structure(elevator room) >>>> >>>> so in 1 compass direction or so to almost straight up i would be blind >>>> >>>> question: >>>> >>>> so is their a particular compas headding that is best to loose? >>> It MUST be a direct view from the antenna to the sat. Otherwise is it >>> just to forget it. With analog reception, the antenna can work very >>> well through a glass window, or while directing the antenna on a >>> reflexion (at least if you can afford a high end tuner in this last case), >>> by but with digital reception, even a tiny glass will cause a >>> lot of trouble (some channels will just disappear), because the digital technique use phase multiplexing >>> and the phase of the signal will change in a non linear fashion through >>> the glass or on a reflexion. >>> >>> Dominique Article: 227722 of rec.radio.amateur.antenna From: helmsman Subject: Is anyone using a Diamond BB7Y? Date: Sat, 05 Aug 2006 17:28:40 -0400 Message-ID: <953ad2h5m4skgb1fc7c3pnkv4bdt690a2r@4ax.com> If you are using a BB7V what do you think about it ? Thanks for your time. Article: 227723 of rec.radio.amateur.antenna Date: Sun, 6 Aug 2006 00:51:42 +0200 From: Dominique Michel Subject: Re: sat ant question Message-ID: <20060806005142.7b4d9f3f@localhost> References: Le Sat, 05 Aug 2006 21:20:00 GMT, Bob a écrit : > Dominique, > I am also speaking from personal and professional experience with Ku > QPSK MCPC systems. Signal loss through the glass in dB correlates with > the same decrease in Eb/No in digital systems. I am curious what your > location is and what systems you have worked with. > Bob > I am in Switzerland now, but the location at that time (2 years ago) was near Malmö in Sweden. The kind of system I was working with was mostly consumer grade electronics, 50 % Nokia complete sat system, and 50 % other brands as philips or samsung. All digital. A few years before that it was mostly analog systems, but the transition between analog and digital was going very fast. I have done a few big installations too, but is was mostly mixed analog-digital cable TV here, or analog sat mixed with normal TV antennas. For the sats, the most wanted was Sirius, Thor, Hotbird and Astra. And it was on ku band too. For the parabol antenna, my favorite ones was nokia and Wisi. Wisi have a good quality and not only consumer grads products, but also professional material, and they have a technical staff that know the job very well. Dominique > Dominique Michel wrote: > > Le Sat, 05 Aug 2006 15:33:07 GMT, > > Bob a écrit : > > > >> Are you asking about amateur satellite operation or TV reception via > >> satellites? Although Dominique’s explanation of digital satellite > >> signals passing through glass may be explained on paper, it has no merit > >> in actual use. Some glass has attenuation at C/Ku frequencies but this > >> purely shows up as signal reduction with associated loss of C/N, BER, > >> etc in digital systems. Analog and digital satellite reception are > >> affected the same. > >> Bob > >> > > > > What I say here is based on personal experience. And it is for TV reception that use phase multiplexing in order to send many different channels on the same frequency. The signal going through a glass is affected in a way that do impossible to receive some channels. A bigger parabol will change nothing, it is just to remove the glass to get all the channels. > > > > You get exactly the same effect if the shape of the parabol is not > > perfect (as it can append after a hazard under transportation), it will > > work just fine for analog reception but with a digital tuner, some > > channels will work when others will not. It is just to change the > > parabol to get all the channels. Sometime, the defect with the shape of > > the parabol is so little as you see nothing with the eyes, but you > > change it against another one from the same model and it just work. I > > installed hundreds of parabol antenna, and it was never a problem with > > a wholesaler or a manufacturer to change a defective parabol, they know this problem very well. > > > > Dominique > > > >> Dominique Michel wrote: > >>> Le Sat, 05 Aug 2006 11:38:23 GMT, > >>> ml a écrit : > >>> > >>>> hi > >>>> > >>>> thinking about getting into sat's, and have a newbie question > >>>> > >>>> i may only be permitted to put up my antennas on a part of the roof that > >>>> would be blocked by a structure(elevator room) > >>>> > >>>> so in 1 compass direction or so to almost straight up i would be blind > >>>> > >>>> question: > >>>> > >>>> so is their a particular compas headding that is best to loose? > >>> It MUST be a direct view from the antenna to the sat. Otherwise is it > >>> just to forget it. With analog reception, the antenna can work very > >>> well through a glass window, or while directing the antenna on a > >>> reflexion (at least if you can afford a high end tuner in this last case), > >>> by but with digital reception, even a tiny glass will cause a > >>> lot of trouble (some channels will just disappear), because the digital technique use phase multiplexing > >>> and the phase of the signal will change in a non linear fashion through > >>> the glass or on a reflexion. > >>> > >>> Dominique Article: 227724 of rec.radio.amateur.antenna From: Walter Maxwell Subject: Re: Radiating Efficiency Message-ID: References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> Date: Sat, 05 Aug 2006 19:32:55 -0400 On Sat, 5 Aug 2006 19:11:17 +0100, "Reg Edwards" wrote: >After all, we already know enough quite enough about radial systems at >HF to design one which will work good enough, performance-wise, to >keep anybody happy. ( BL&E's work, as good as it may be, does not >apply at HF.) > >Just lay one or two dozen radials, in ordinary soils, with lengths >equal to about half antenna height. Which is a good enough >rule-of-thumb for anybody who doesn't expect to win contests because >he has the advantage of 0.05 S-units. > >And extremely few people know what their local soil resistivity is >within +/- 40 percent. It's largely guesswork! >Reg, G4FGQ > Hi Reg, You're saying that BL&E's work doesn't apply at HF. I believe that's an overstatement. They've shown that with about 100 radials of 0.4 lamba length the result is almost perfect ground, regardless of the ground conditions beneath the radials. I contend that using the radial setup as described above will always result in a near-perfect ground at any HF frequency, with close to 100 percent efficiency. Would you not agree? Walt, W2DU Article: 227725 of rec.radio.amateur.antenna Subject: Re: If you had to use CW to save someone's life, would that person die? From: Slow Code References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> <1154574315.819259.204140@b28g2000cwb.googlegroups.com> <6gr3d21444qdt5m6mr1e1jpavltvso929p@4ax.com> <1154614371.351691.272240@s13g2000cwa.googlegroups.com> <44d20fd9$0$2919$ecde5a14@news.coretel.net> <44d216cb$0$2920$ecde5a14@news.coretel.net> <6ic7d2diqkk5go86t8bo86ik3c43t3laco@4ax.com> <44d3b80f$0$2919$ecde5a14@news.coretel.net> <1154726291.953345.94290@h48g2000cwc.googlegroups.com> <1154806401.369014.158580@i3g2000cwc.googlegroups.com> Message-ID: Date: Sat, 05 Aug 2006 23:31:56 GMT "an_old_friend" wrote in news:1154806401.369014.158580@i3g2000cwc.googlegroups.com: > > Slow Code wrote: >> "an old freind" wrote in >> news:1154726291.953345.94290@h48g2000cwc.googlegroups.com: >> >> > > >> >> It's hard to figure out what you're actually trying to say sometimes >> Mark, but what it looks like you were trying to convey to the race >> organizer is that you're retarded. > > never hard to understand you want Ham radio to die if can't retreat > into the past but then if you got what you wanted Ham radio would truly > be without a future Handi-Hams still has a spot for you on the short bus. Sc Article: 227726 of rec.radio.amateur.antenna Date: Sat, 05 Aug 2006 19:43:02 -0400 From: Mike Coslo Subject: Re: Radiating Efficiency References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> <37r9d212pojknc4gifpd1iro0d7h8n8v1i@4ax.com> Message-ID: Richard Clark wrote: > On Sat, 5 Aug 2006 19:11:17 +0100, "Reg Edwards" > wrote: > > >>Thank you very much for the results on 8 radials. >> >>As expected, it seems that for small numbers of radials the resonance >>effects are begining to appear again. >> >>I have ideas as to why this should happen. > > > Hi Reggie, > > You "should" if you had read Brown, Lewis, and Epstein. They > discussed this nearly 70 years ago. Cut 'im a break Richard! He was just a little kid at the time! ;^) `73 de Mike KB3EIA - Article: 227727 of rec.radio.amateur.antenna From: "an old friend" Subject: Re: If you had to use CW to save someone's life, would that person die? Date: 6 Aug 2006 00:54:48 -0700 Message-ID: <1154850887.959554.15680@p79g2000cwp.googlegroups.com> References: <1153664765.447946.4510@s13g2000cwa.googlegroups.com> Slow Code wrote: > "an_old_friend" wrote in > news:1154806401.369014.158580@i3g2000cwc.googlegroups.com: > > Handi-Hams still has a spot for you on the short bus. nope handihams has no respect for LD's at all > > Sc Article: 227728 of rec.radio.amateur.antenna From: "Reg Edwards" References: <1qOzg.181008$771.118115@edtnps89> <8h2Ag.182604$S61.120179@edtnps90> <1ucAg.136902$A8.3454@clgrps12> Subject: Re: Radiating Efficiency Date: Sun, 6 Aug 2006 09:15:04 +0100 Message-ID: > They've shown that with about 100 radials of 0.4 lamba length the result is > almost perfect ground, regardless of the ground conditions beneath the radials. > > I contend that using the radial setup as described above will always result in a > near-perfect ground at any HF frequency, with close to 100 percent efficiency. > > Would you not agree? > > Walt, W2DU ====================================== My dear Walt, I haver never disagreed. How can one disagree with a statement of the bleeding obvious? Indeed, my program RADIAL3 confirms it. And so will NEC4 if you will allow it time to generate some results. ----- Reg, G4FGQ. Article: 227729 of rec.radio.amateur.antenna From: Cathy@noosempty.net Subject: Mega promos dans notre sex shop Date: 06 Aug 2006 11:53:39 GMT Message-ID: <44d5d842$0$831$ba4acef3@news.orange.fr>
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Article: 227730 of rec.radio.amateur.antenna From: Cindy@amplend.com Subject: TELECHARGEZ DES VIDEOS X LIBREMENT Date: 06 Aug 2006 11:53:43 GMT Message-ID: <44d5d846$0$895$ba4acef3@news.orange.fr>
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Article: 227731 of rec.radio.amateur.antenna From: priscilla@canaweb.ca Subject: jeunes filles 18 ans perverses Date: 06 Aug 2006 11:53:43 GMT Message-ID: <44d5d846$0$827$ba4acef3@news.orange.fr>







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Article: 227732 of rec.radio.amateur.antenna From: "Jimmie D" References: <1154100643.691199.3530@b28g2000cwb.googlegroups.com> Subject: Re: base loading vertical with roller inductor? Message-ID: Date: Sat, 5 Aug 2006 08:06:03 -0400 "Bill Turner" wrote in message news:tom1d210e5c6b53cpismso0ftkij3shtci@4ax.com... > ORIGINAL MESSAGE: > > On Wed, 2 Aug 2006 11:11:08 -0400, "Jimmie D" > wrote: > >>Hi Bill, can you tell m something about your setup with the roller >>inductor. >>I tried it and was not very happy with it. I guess I could have tried a >>slower motor and it seemed like it require cleaning a couple of times a >>month. I still have the old stuff around and may try it again if I thought >>I >>could get it to work better. > > ------------ REPLY SEPARATOR ------------ > > At the time I lived in the Seattle area so waterproofing was a must. I > built a plywood box with a plexiglas front and sealed it with > silicone. I used it for a couple of years and never had to clean the > roller inductor. One thing I didn't mention but should have is to have > most of the loading inductance in a separate high Q coil, and use the > roller only for tuning. IOW, don't try to use the roller for the > entire loading coil or it will tune too fast and probably won't be > very high Q either. As with mobile antennas, a center coil is best, or > at least as high off the ground as practical. If you don't have an MFJ > SWR analyzer or the equivalent, buy or borrow one. I would not attempt > this kind of project without one! > > The motor was one I got from All Electronics in California. They seem > to have lots of surplus ones available. Something around five RPM > would be about right. They call them "gearhead" or something like that > because they have the reduction gears built in. > > Does that answer your questions? > > Bill, W6WRT Ok, that helped. My motor turned even slower than yours but I was using only the roller inductor. The next time I try this I may use a stepper motor. Article: 227733 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <1154575669.483390.122580@h48g2000cwc.googlegroups.com> <1154610189.274197.177730@h48g2000cwc.googlegroups.com> <44d252bd$0$35072$4fafbaef@reader4.news.tin.it> <44d45010$0$35074$4fafbaef@reader4.news.tin.it> Subject: Re: Question on carbon fibre fishing rod Date: Sun, 6 Aug 2006 16:08:59 +0200 Message-ID: <44d5f7fb$0$47969$4fafbaef@reader3.news.tin.it> > Whether the current flows in the wire or in the rod depends on > inductance and inductive reactance. >=20 > A thin wire has greater inductance and impedance per unit length than > a thick rod. True, the rod having a resistance by far higher than that of the copper = wire, I would believe that current will anyway pass through the wire, = despite its lower diameter. 73 Tony Article: 227734 of rec.radio.amateur.antenna From: "Antonio Vernucci" References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <1154575669.483390.122580@h48g2000cwc.googlegroups.com> <1154610189.274197.177730@h48g2000cwc.googlegroups.com> <44d252bd$0$35072$4fafbaef@reader4.news.tin.it> <44d45010$0$35074$4fafbaef@reader4.news.tin.it> <1154790677.995708.44390@n13g2000cwa.googlegroups.com> Subject: Re: Question on carbon fibre fishing rod Date: Sun, 6 Aug 2006 17:06:38 +0200 Message-ID: <44d6057e$0$35081$4fafbaef@reader4.news.tin.it> Hi Dan thanks for your in-depth analysis on EZ-NEC. The only step that surpises = me a bit is that, with the top and bottom shorting wires in place, the = current through the rod gets quite high, almost 2/3 that of the wire. On = the other hand is always difficult to predict reality when = electromagnetic phenomena are involved. The next test you suggested, i.e. with the wire fully insulated from the = rod, is just what I had in mind to do. A spacing of about 1-inch would = be easy to get, by sliding the copper wire through the rings where the = fishing nylon wire is supposed to run. So I'll do that first. I have a = good quantity of silver-plated teflon-coated wire, so will try with that = as it will stand a fairly voltage. I should be able to make that test by = next monday or tuesday afternoon, and I will report results here. 73 Tony I0JX ha scritto nel messaggio = news:1154790677.995708.44390@n13g2000cwa.googlegroups.com... > Tony, >=20 > >From an EZNEC model with essentially the situation you described: > Wire numbers 2 and 5 are both 7.9m high, frequency 10MHz, fed against = a > radial system in free space. >=20 > Wire number 2 is 25.4mm diameter, 21 segments, a 10 ohm load in each > segment, total "rod resistance" 210 ohms + negligable copper loss. = The > wire centers are 7cm apart. Wire number 5 is 2mm diameter copper. > Wires 2 and 5 are shorted together top and bottom (no contact along = the > length, but maybe we can see why you had arcing) >=20 > As you can see below, the currents in the two "wires" with the top and > bottom shorted are not in phase. Moreover, the current in the rod > (Wire No. 2) is quite appreciable, almost 2/3 that of the wire. >=20 >=20 > Wire No. 2: > Segment Conn Magnitude (A.) Phase (Deg.) > te1 W4E1 .39744 -167.9 > 2 .40049 -168.9 > 3 .39918 -169.3 > 4 .39463 -169.2 > 5 .38725 -168.8 > 6 .3773 -168.1 > 7 .36499 -166.9 > 8 .35056 -165.4 > 9 .33425 -163.5 > 10 .31635 -161.0 > 11 .29723 -157.9 > 12 .27734 -154.0 > 13 .25727 -149.2 > 14 .23781 -143.2 > 15 .22002 -135.8 > 16 .20528 -126.8 > 17 .19529 -116.1 > 18 .19188 -104.1 > 19 .19661 -91.39 > 20 .21058 -78.89 > 21 W3E1 .23611 -66.69 >=20 > Wire No. 5: > Segment Conn Magnitude (A.) Phase (Deg.) > 1 W6E1 .64698 170.23 > 2 .66204 169.08 > 3 .67227 168.00 > 4 .67834 166.94 > 5 .68045 165.86 > 6 .67871 164.76 > 7 .6732 163.63 > 8 .66403 162.44 > 9 .6513 161.18 > 10 .63513 159.83 > 11 .61567 158.39 > 12 .59307 156.82 > 13 .56752 155.11 > 14 .53922 153.20 > 15 .50842 151.06 > 16 .47537 148.63 > 17 .44036 145.82 > 18 .40374 142.51 > 19 .36589 138.50 > 20 .32725 133.51 > 21 W3E2 .28776 126.90 >=20 > So how's the loss? Well, here's the table of load data: >=20 >=20 > Frequency =3D 10 MHz >=20 > Load 1 Voltage =3D 14.71 V. at -167.86 deg. > Current =3D 1.471 A. at -167.86 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 21.62 watts >=20 > Load 2 Voltage =3D 14.82 V. at -168.9 deg. > Current =3D 1.482 A. at -168.9 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 21.96 watts >=20 > Load 3 Voltage =3D 14.77 V. at -169.29 deg. > Current =3D 1.477 A. at -169.29 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 21.81 watts >=20 > Load 4 Voltage =3D 14.6 V. at -169.24 deg. > Current =3D 1.46 A. at -169.24 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 21.32 watts >=20 > Load 5 Voltage =3D 14.33 V. at -168.83 deg. > Current =3D 1.433 A. at -168.83 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 20.53 watts >=20 > Load 6 Voltage =3D 13.96 V. at -168.07 deg. > Current =3D 1.396 A. at -168.07 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 19.49 watts >=20 > Load 7 Voltage =3D 13.5 V. at -166.95 deg. > Current =3D 1.35 A. at -166.95 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 18.24 watts >=20 > Load 8 Voltage =3D 12.97 V. at -165.43 deg. > Current =3D 1.297 A. at -165.43 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 16.82 watts >=20 > Load 9 Voltage =3D 12.37 V. at -163.46 deg. > Current =3D 1.237 A. at -163.46 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 15.29 watts >=20 > Load 10 Voltage =3D 11.7 V. at -160.97 deg. > Current =3D 1.17 A. at -160.97 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 13.7 watts >=20 > Load 11 Voltage =3D 11 V. at -157.86 deg. > Current =3D 1.1 A. at -157.86 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 12.09 watts >=20 > Load 12 Voltage =3D 10.26 V. at -153.99 deg. > Current =3D 1.026 A. at -153.99 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 10.53 watts >=20 > Load 13 Voltage =3D 9.519 V. at -149.17 deg. > Current =3D 0.9519 A. at -149.17 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 9.061 watts >=20 > Load 14 Voltage =3D 8.799 V. at -143.19 deg. > Current =3D 0.8799 A. at -143.19 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 7.742 watts >=20 > Load 15 Voltage =3D 8.141 V. at -135.8 deg. > Current =3D 0.8141 A. at -135.8 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 6.627 watts >=20 > Load 16 Voltage =3D 7.595 V. at -126.79 deg. > Current =3D 0.7595 A. at -126.79 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 5.769 watts >=20 > Load 17 Voltage =3D 7.226 V. at -116.11 deg. > Current =3D 0.7226 A. at -116.11 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 5.221 watts >=20 > Load 18 Voltage =3D 7.099 V. at -104.08 deg. > Current =3D 0.7099 A. at -104.08 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 5.04 watts >=20 > Load 19 Voltage =3D 7.274 V. at -91.39 deg. > Current =3D 0.7274 A. at -91.39 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 5.292 watts >=20 > Load 20 Voltage =3D 7.791 V. at -78.88 deg. > Current =3D 0.7791 A. at -78.88 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 6.071 watts >=20 > Load 21 Voltage =3D 8.736 V. at -66.69 deg. > Current =3D 0.8736 A. at -66.69 deg. > Impedance =3D 10 + J 0 ohms > Power =3D 7.632 watts >=20 > Total applied power =3D 1535 watts >=20 > Total load power =3D 271.9 watts > Total load loss =3D 0.846 dB >=20 > The situation is VERY much improved by simply removing the top and > bottom shorting wires (this changes the base impedance very much, by > the way. I adjusted the source to still give ~1500 watts applied) >=20 > Total applied power =3D 1576 watts >=20 > Total load power =3D 30.53 watts > Total load loss =3D 0.085 dB >=20 > The current in the two wires isn't in phase either, but the average > magnitude of the current in the rod is more than a factor of ten below > the average magnitude of current in the wire. >=20 > So, space the wire a couple of inches out from the rod with insulators > and you should be fine, except, as Reg said before, where the rod is > 1/2 wavelength long. >=20 > If you still get heating, I suppose you'll just have to use the rod as > a center support for an inverted-vee antenna or something! >=20 > The arcing is coming from the fact that the currents are out-of-phase > by some amount (40 degrees) in the two conductors... and so are the > voltages... you get a potential difference between a point on the wire > and the corresponding point on the rod. I doubt it's sufficient to > jump any distance air gap, it's more that the carbon can't take the > current that wants to flow between the rod and wire and is burning, = but > that's just a guess, and you know how good my guess was originally. >=20 > Dan > Article: 227735 of rec.radio.amateur.antenna From: "David G. Nagel" Subject: Re: Question on carbon fibre fishing rod Date: Sun, 06 Aug 2006 10:18:17 -0500 Message-ID: <12dc21sps27jcaa@corp.supernews.com> References: <44d0e1b6$0$35077$4fafbaef@reader4.news.tin.it> <1154555654.618018.192280@i42g2000cwa.googlegroups.com> <1154575669.483390.122580@h48g2000cwc.googlegroups.com> <1154610189.274197.177730@h48g2000cwc.googlegroups.com> <44d252bd$0$35072$4fafbaef@reader4.news.tin.it> <44d45010$0$35074$4fafbaef@reader4.news.tin.it> <44d5f7fb$0$47969$4fafbaef@reader3.news.tin.it> Antonio Vernucci wrote: >>Whether the current flows in the wire or in the rod depends on >>inductance and inductive reactance. >> >>A thin wire has greater inductance and impedance per unit length than >>a thick rod. > > > True, the rod having a resistance by far higher than that of the copper wire, I would believe that current will anyway pass through the wire, despite its lower diameter. > > 73 > > Tony Actually if the rod conducts it will share the current flow according to the law or parallel resistance. Dave WD9BDZ Article: 227736 of rec.radio.amateur.antenna From: "Harbin Osteen" References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> <44D0D8A2.FECE1660@shaw.ca> <6pa8d2hhk93l678n7tuei578s3ptftblbh@4ax.com> Subject: Re: Any info on this type of mobile antenna? Date: Sun, 6 Aug 2006 11:42:39 -0700 Message-ID: <1KmdnQFiycKDpUvZnZ2dnUVZ_ridnZ2d@adelphia.com> "Richard Clark" wrote in message news:6pa8d2hhk93l678n7tuei578s3ptftblbh@4ax.com... > On Fri, 4 Aug 2006 17:47:31 -0700, "Harbin Osteen" > wrote: > >> Nope, not a reflector. I have seen these on several types >>of German armor, and it seems that this is the way it is used. >>I'm trying to understand how this type of antenna works, and >>if it would scale down to VHF. It is mostly seen on German >>armored scout cars, such as the link below.: > > Hi Harbin, > > On closer research, it is a loop antenna suited for MF to low HF (as > high as 40M). > > This is from an interesting article in how the US Army has discovered > it needs HF comm gear to do the job satellites and VHF repeaters were > suppose to do: > http://www.gordon.army.mil/AC/Winter/Winter%2001/HFIBCT.htm > > 73's > Richard Clark, KB7QHC Hi Richard: I happened to trip across this website also, and it is just what I was looking for. Thanks for the response Richard. -- SeeYaa:) Harbin Osteen KG6URO !sdohtem noitpyrcne devorppa-tnemnrevog troppus I - Article: 227737 of rec.radio.amateur.antenna From: Richard Clark Subject: Re: Any info on this type of mobile antenna? Date: Sun, 06 Aug 2006 11:55:51 -0700 Message-ID: References: <1PGdnVocUI8aP03ZnZ2dnUVZ_u6dnZ2d@adelphia.com> <44D0D8A2.FECE1660@shaw.ca> <6pa8d2hhk93l678n7tuei578s3ptftblbh@4ax.com> <1KmdnQFiycKDpUvZnZ2dnUVZ_ridnZ2d@adelphia.com> On Sun, 6 Aug 2006 11:42:39 -0700, "Harbin Osteen" wrote: > I happened to trip across this website also, and it is just what I was >looking for. Hi Harbin, After I posted, I got your follow-on with the same address. Spooky, but seems we both homed in with the same Google terms. So now I know what the communications cars looked like back then, and more interestingly, that the US Army had walked away from their historical HF operations much to the loss of their embedded knowledge. It would seem if we ever went to war, they would be drafting Hams with their gear again like in WWII. 73's Richard Clark, KB7QHC Article: 227738 of rec.radio.amateur.antenna From: jpopelish@rica.net Subject: Re: Rule of Thumb for coax chokes Date: 6 Aug 2006 13:14:11 -0700 Message-ID: <1154895251.247543.55250@b28g2000cwb.googlegroups.com> References: <1T6Ag.1806$kO3.783@newssvr12.news.prodigy.com> John Popelish wrote: > Digikey carries a pretty broad line of Steward long form ferrite bead > cores. You can check the specifications at http://www.steward.com/ > > For instance, core HFB143064-300 has an impedance of about 180 ohms at > 146 MHz. Type HF is their highest frequency material. > > Core 28B0562-200 (same size in the lower frequency, 28 material) > produces an impedance of about 360 ohms per core. > > I think both of these would fit over RG8X and are about an inch and an > eighth long. By the way, if you want the convenience of the snap around cores in a plastic retainer, part # 28A0593-0A2 provides 450 ohms per core at 146 MHz.. They cost about $2 plus shipping. They are about 2 and 1/4 inches long. Article: 227739 of rec.radio.amateur.antenna From: "Jim" Subject: Re: Question for You Grounding Gurus Date: 6 Aug 2006 17:34:32 -0700 Message-ID: <1154910872.469811.101930@h48g2000cwc.googlegroups.com> References: <1153437176.242544.67620@m79g2000cwm.googlegroups.com> Tom, This is a bit off-topic, but can I ask you .. > Lightning protection comes much more from how you wire things than a > few ground rods...or even a dozen ground rods. As a matter of fact > adding or improving a ground can make things worse if the bonding and > entrance is installed wrong. > > The station ground always should attach at the cable entrance point, > and that entrance MUST be bonded to the utilitly entrance ground. Many > people don't do this even though it is critical. Did you do this yourself, or did you get a pro of some kind? I have tried to understand the advice I have seen (in particular the ARRL articles) but I've only become convinced that it needs more knowledge than I have, or at least that I could easily do exactly the wrong thing. Would any electrician know enough (I'm suspecting not) or some other professional? Jim Article: 227740 of rec.radio.amateur.antenna Date: Mon, 07 Aug 2006 10:01:27 +0800 From: me Subject: Re: Dick Smith Radio Direction Finder References: <43C15BA4.3F39@orcon.net.nz> <43c793c4$0$2255$afc38c87@news.optusnet.com.au> <43C80CF5.2B5C@orcon.net.nz> <43c83db7$0$17190$afc38c87@news.optusnet.com.au> <43c8eaa8$0$13318$afc38c87@news.optusnet.com.au> Message-ID: <44d69eec@quokka.wn.com.au> Kev wrote: Kev a tanker wanker ,,,, do tell more Kev Deck or ER ? > news wrote: > >> yes thanks glenn. I would like a copy of the circuit. >> >> email james_about@hotmail.com with the info please. >> >> Any thing you need also. I keep a fairly extensive collection of radio >> software and circuits. >> >> And gidday to Kev ....tanker wanker. private joke. >> >> > > :) > > > Kev