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#41
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Vincent antenna
art wrote:
W8JI is a competant engineer and well versed in "traditional" antenna design but he is not without fault or error since he is a human being. He is absolutely wrong about the phase shift through a 75m bugcatcher loading coil. Over on QRZ.com, he tried to prove something using the lumped inductance in EZNEC. :-) -- 73, Cecil http://www.w5dxp.com |
#42
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Vincent antenna
On Tue, 27 Nov 2007 20:00:22 -0800 (PST), art
wrote: Why not educate the masses with respect to waves versus particles, everybody will be very interested as to what emanates from a radiator or visa versa when on the receiving end. How curious, Arthur, that I asked you for EXACTLY the same information and you showed absolute repugnance towards the topic! Already bored? 73's Richard Clark, KB7QHC |
#43
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Vincent antenna
Cecil Moore wrote:
art wrote: W8JI is a competant engineer and well versed in "traditional" antenna design but he is not without fault or error since he is a human being. He is absolutely wrong about the phase shift through a 75m bugcatcher loading coil. Over on QRZ.com, he tried to prove something using the lumped inductance in EZNEC. :-) People who want to know what W8JI actually believes, as opposed to what Cecil says he believes, should go to W8JI's website. And, no, Cecil, your little theory about phase shifts across loading coils, which you can't substantiate through experiment, or even through any type of rigorous theory, is nothing more than an exercise in philosophical fantasy. 73, Tom Donaly, KA6RUH |
#44
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Loading Coils; was : Vincent antenna
Tom Donaly wrote:
People who want to know what W8JI actually believes, as opposed to what Cecil says he believes, should go to W8JI's website. I agree, Tom, and here is the URL: http://www.w8ji.com/inductor_current_time_delay.htm W8JI takes a 2" dia, 100 turn, 10 inch long coil, and claims the actual delay through that coil is 3 nS or 4.5 degrees. (The formula for the velocity factor of such a coil yields ~0.033 at 4 MHz making the actual delay ~37 degrees or ~25 nS at 4 MHz.) W8JI's mistake was using standing wave current to try to measure that delay. The phase of standing wave current changes hardly at all and is useless for measuring delay. If the delay is to be measured by observing phase shifts, then traveling wave current should be used. That would require loading the coil with a resistor equal to its characteristic impedance. Another way to measure the delay is to set the coil up as a helical antenna over a ground plane and find the self-resonant frequency which would mean the phase shift through the coil is 90 degrees at that self-resonant frequency. Even though the delay changes with frequency, it is highly unlikely to drop from 90 degrees to 4.5 degrees in a few MHz. ... your little theory about phase shifts across loading coils, which you can't substantiate through experiment, or even through any type of rigorous theory, is nothing more than an exercise in philosophical fantasy. Actually, it is an exercise in the physics of reality. A 3nS delay through a 100 uH coil is the real "exercise in philosophical fantasy" and obviously impossible. Try it with a TDR and see what you get. Heck, try it at DC and see what you get. At his request, I sent a test setup schematic to one of the gurus on this newsgroup so he could prove me wrong. He has gone silent and stopped answering my emails. I expect to see a paper or magazine article announcing "his discovery". -- 73, Cecil http://www.w5dxp.com |
#45
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Loading Coils; was : Vincent antenna
On Wed, 28 Nov 2007 13:25:34 -0600, Cecil Moore
wrote: At his request, I sent a test setup schematic to one of the gurus on this newsgroup so he could prove me wrong. He has gone silent and stopped answering my emails. I expect to see a paper or magazine article announcing "his discovery". Art probably had more pressing issues with the Patent Office. |
#46
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Loading Coils; was : Vincent antenna
Cecil Moore wrote:
Tom Donaly wrote: People who want to know what W8JI actually believes, as opposed to what Cecil says he believes, should go to W8JI's website. I agree, Tom, and here is the URL: http://www.w8ji.com/inductor_current_time_delay.htm W8JI takes a 2" dia, 100 turn, 10 inch long coil, and claims the actual delay through that coil is 3 nS or 4.5 degrees. (The formula for the velocity factor of such a coil yields ~0.033 at 4 MHz making the actual delay ~37 degrees or ~25 nS at 4 MHz.) W8JI's mistake was using standing wave current to try to measure that delay. The phase of standing wave current changes hardly at all and is useless for measuring delay. If the delay is to be measured by observing phase shifts, then traveling wave current should be used. That would require loading the coil with a resistor equal to its characteristic impedance. Another way to measure the delay is to set the coil up as a helical antenna over a ground plane and find the self-resonant frequency which would mean the phase shift through the coil is 90 degrees at that self-resonant frequency. Even though the delay changes with frequency, it is highly unlikely to drop from 90 degrees to 4.5 degrees in a few MHz. ... your little theory about phase shifts across loading coils, which you can't substantiate through experiment, or even through any type of rigorous theory, is nothing more than an exercise in philosophical fantasy. Actually, it is an exercise in the physics of reality. A 3nS delay through a 100 uH coil is the real "exercise in philosophical fantasy" and obviously impossible. Try it with a TDR and see what you get. Heck, try it at DC and see what you get. At his request, I sent a test setup schematic to one of the gurus on this newsgroup so he could prove me wrong. He has gone silent and stopped answering my emails. I expect to see a paper or magazine article announcing "his discovery". What is the characteristic impedance of Tom's coil? How do you define the characteristic impedance of a coil of wire? If you were to replace Tom's coil with a shorted length of transmission line, given that jXl = jZo(tan(BL)), which one of the infinite combinations of Zo and L would you use, given that any of them would resonate your antenna? Would they all have the same "phase shift?" What's your formula for the velocity factor of Tom's coil? Is it from the same Tesla coil crackpot you quoted in previous posts? Have you used the test setup you mentioned, yourself? Spit out some numbers. 73, Tom Donaly, KA6RUH (P.S. For those who don't know: "B" is my version of the Greek letter "Beta," and L is the length of the transmission line, so BL is the length of the line in radians. In order for jXl to stay the same, given a change in Zo, the length of the transmission line has to change, too. Since the length isn't unique, the delay isn't either, and even if Cecil's transmission line coil did act like a transmission line, the delay could be changed to anything anyone wanted it to, just by changing the coil dimensions. Of course, Cecil can't prove that his coil is much of a transmission line, so the point is moot.) |
#47
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Loading Coils; was : Vincent antenna
Tom Donaly wrote:
What is the characteristic impedance of Tom's coil? A few thousand ohms. Use equation 50 at: http://www.ttr.com/TELSIKS2001-MASTER-1.pdf What's your formula for the velocity factor of Tom's coil? Is it from the same Tesla coil crackpot you quoted in previous posts? Do you reject all IEEE white papers? The formula is equation 32. -- 73, Cecil http://www.w5dxp.com |
#48
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Loading Coils; was : Vincent antenna
AI4QJ wrote:
That is his "obvious" explanation. He should remove that from his webpage as it is rather embarassing. W8JI made a gross error in his measurement and then tried to rationalize the impossible result. -- 73, Cecil http://www.w5dxp.com |
#49
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Loading Coils; was : Vincent antenna
On Thu, 29 Nov 2007 03:58:11 GMT, Cecil Moore
wrote: W8JI made a gross error in his measurement and then tried to rationalize the impossible result. Given the volume of smoke generated here (over an issue that was long ago laid in its coffin), did he violate your patented technique? You and Art seem intent on collecting on a bet, or a debt, or otherwise mooching validation, because if you two had such dead-to-rights positions, they wouldn't require exhumation from the grave to prop the corpses on soap box pedestals as resurrected proof. |
#50
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Loading Coils; was : Vincent antenna
I see Cecil's temporarily run out of steam on his alternative theories
of transmission line operation and so has fallen back to his equally imaginative pseudo-science of loading coils. I made and posted careful measurements on this group long ago of a physically small coil to refute some of the stranger claims being made. I can only describe as disgusting the ducking, weaving, hemming, and hawing Cecil and Yuri went through in trying to predict using their imaginative theories what the results would be. Of course, like any competent fortune tellers, once the results were given they claimed to have known all along. It's all there in the archives for anybody who has the stomach for it. I don't. Roy Lewallen, W7EL |
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