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#41
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Do you have a quote showing exactly what Tom said, in context?
Roy Lewallen, W7EL Richard Harrison wrote: Art Unwin wrote: "What did he say that was wrong?" Recently Tom argued with Yuri that loading coils must have the same current in and out. Circuit theory does not directly apply in all cases due to the possibility of a reflected wave on the coil and due to radiation from a loading coil. Did Tom ever admit that it`s possible that current into one end of the coil does not necessarily equal the current at its other end? Best regards, Richard Harrison, KB5WZI |
#42
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![]() "Richard Harrison" wrote in message ... Art Unwin wrote: "What did he say that was wrong?" I said more than that!, Ae you cherry picking again? You did not prove your case against Tom in your allegation, period Now you scurried away to something else without justifying that your original is correct and Tom is wrong! Climbing towers to tighten nuts under direction does not make you an antenna expert where as Tom has proved himself amoung the amateur community time over time. Recently Tom argued with Yuri that loading coils must have the same current in and out. Circuit theory does not directly apply in all cases due to the possibility of a reflected wave on the coil and due to radiation from a loading coil. Did Tom ever admit that it`s possible that current into one end of the coil does not necessarily equal the current at its other end? I haven't seen a posting from Tom on this newsgroup for a very long time. Did you confront him to his face about this or are you talking about him in his absence? Go to EHAM and confront him like a man especially if this original confrontation occured else where. Ifyou have a problem with some one about something then talk to him directly instead of throwing mud when he isn't looking. There have been many statements made about Tom lately that I can't verify in RRAA records so why are you bringing mud to this table especially when the target is not here to defend himself and especially if your charges are scurrilous and without depth Art Best regards, Richard Harrison, KB5WZI |
#43
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I have a great deal of respect for Tom, W8JI. In fact, there are few
people I respect as much. I regard him as being exceptionally honest, very analytical, and always seeking to find the truth and increase his knowledge. Whenever his view of how things work have been shown to be wrong, I've found him to readily accept the corrected view, and be grateful of the opportunity to learn something new. I've also learned from him on more than one occasion. One notable case is the idea of using a balun at the input of a tuner to improve the balun's balancing properties. I had believed it to work, but he showed me where I was wrong, giving me the opportunity to increase my knowledge. I find it contemptable and cowardly to attack him -- or anyone -- in a forum where he's not a participant and isn't present to correct misquotes, quotes taken out of context, and otherwise respond and defend himself. People doing so should instead sign onto one of the election campaigns or go on AM talk radio, where such gutless, dishonest, and mean-spirited activity is the accepted norm. I believe the Russians have a word for this kind of cowardly and "uncultured" activity -- something like "nyekulturny". Maybe Yuri knows. Roy Lewallen, W7EL |
#44
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#45
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Richard Harrison wrote:
Did Tom ever admit that it`s possible that current into one end of the coil does not necessarily equal the current at its other end? His own measurements proved that the currents at each end of air-core loading coils are NOT equal. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#46
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Roy Lewallen wrote:
Do you have a quote showing exactly what Tom said, in context? Here's one from his web page: "What determines current distribution in a loading coil? The capacitance to the outside world and the impedance above the loading coil. The current in any inductor would be equal at each end except for displacement currents, which are "imaginary currents" that flow through capacitance." He completely ignores the fact that, for a standing-wave antenna, the net current is the superposed phasor sum of the forward current and reflected current and whatever phase shift occurs through the coil is doubled because those two currents are traveling in opposite directions. He is thinking lumped circuit model when he should be using a distributed network model. What he says is reasonably accurate for a traveling-wave antenna but certainly not for a standing-wave antenna. EZNEC clearly illustrates the difference in the currents when the coil is modeled as a coil of wire segments and not as a lumped inductor. Anyone who would like a copy of the EZNEC file need only request it. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#47
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Roy Lewallen wrote:
One notable case is the idea of using a balun at the input of a tuner to improve the balun's balancing properties. I had believed it to work, but he showed me where I was wrong, giving me the opportunity to increase my knowledge. Over on eHam.net, he just admitted that a real world application does not act like that perfect paper solution. He said: "In real life, stray capacitances from the network to ground modify the behavior of the system when the balun is moved ..." -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#48
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Cecil Moore wrote:
Roy Lewallen wrote: Do you have a quote showing exactly what Tom said, in context? Here's one from his web page: "What determines current distribution in a loading coil? The capacitance to the outside world and the impedance above the loading coil. The current in any inductor would be equal at each end except for displacement currents, which are "imaginary currents" that flow through capacitance." He completely ignores the fact that, for a standing-wave antenna, the net current is the superposed phasor sum of the forward current and reflected current and whatever phase shift occurs through the coil is doubled because those two currents are traveling in opposite directions. He is thinking lumped circuit model when he should be using a distributed network model. What he says is reasonably accurate for a traveling-wave antenna but certainly not for a standing-wave antenna. EZNEC clearly illustrates the difference in the currents when the coil is modeled as a coil of wire segments and not as a lumped inductor. Anyone who would like a copy of the EZNEC file need only request it. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- Current waves can travel in two directions at the same time. Charge can't. For a guy who doesn't seem to be able to make the distinction, you don't have any business criticizing Tom Rauch's understanding of the situation. 73, Tom Donaly KA6RUH |
#49
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On Tue, 24 Aug 2004 00:54:10 GMT, Richard Clark
wrote: Now, I know that such antennas are not designed to be transmit antennas (and again, perhaps too short to boot); so I will leave that to others to engage as a receive antenna if they doubt reciprocity (or I will do that later this eve for them as I often have to). Hi All, I've repeated the models with longer runs: 1000 meters length @ 80M. For transmits, the single wire over ground shows a gain of 0.42dBi at 10° but with a F/B of 16.4dB. EZNEC proclaims the model exhibits 17dB loss. For transmits, the double wire over ground shows a gain of 1.2dBi at 10° but with a F/B of 11.7dB. EZNEC proclaims the model exhibits 17dB loss. However, Beverages are not typically the first choice for transmission, but rather reception. Does reciprocity hold? As no one has offered to help the Little Red Hen, would they care to share in the cake? For the receive single wire Beverage @ 10° w/600 Ohm load Total load power = 5.543E-07 watts For the receive double wire Beverage @ 10° w/600 Ohm load Total load power = 6.623E-07 watts Now, if we compare the two receive loads we find they differ by .77dB which is the same difference for the transmission models. By most accounts, that means reciprocity prevails. By further accounts, that means the double wire system is superior - if you want to lay out 1000 meters of wire for less than one dB (that pesky one dB value judgment again). By this point, what with all the trolling going on and so little actual technical content, What was this all about? 73's Richard Clark, KB7QHC |
#50
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![]() "Richard Clark" asked - Does reciprocity hold? ------------------------------------------- How dare you question it? ---- Punchinello. |
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