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#1
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Tom Ring wrote:
Or, to put it more "accurately", from Cecil's perspective, it fills in the missing degrees at the position the coil sits. No, in the case of a base-loaded antenna, the "missing" degrees are filled in at the impedance discontinuity *between* the coil and the stinger. -- 73, Cecil http://www.qsl.net/w5dxp |
#2
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Cecil Moore wrote:
Tom Ring wrote: Or, to put it more "accurately", from Cecil's perspective, it fills in the missing degrees at the position the coil sits. No, in the case of a base-loaded antenna, the "missing" degrees are filled in at the impedance discontinuity *between* the coil and the stinger. And that differs from your bugcatcher how? tom K0TAR |
#3
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On Thu, 27 Apr 2006 21:58:07 -0500, Tom Ring
wrote: No, in the case of a base-loaded antenna, the "missing" degrees are filled in at the impedance discontinuity *between* the coil and the stinger. And that differs from your bugcatcher how? Hi Tom, His has an event horizon, beyond which all missing degrees disappear by superimposition. 73's Richard Clark, KB7QHC |
#4
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Tom Ring wrote:
Cecil Moore wrote: No, in the case of a base-loaded antenna, the "missing" degrees are filled in at the impedance discontinuity *between* the coil and the stinger. And that differs from your bugcatcher how? The whole point is that it doesn't differ. That's how my bugcatcher works. Here are the three parts to the answer. 1. The base-loading coil furnishes a delay equal to a certain number of degrees which is nowhere near zero degrees. Half of a coil self-resonant at 4 MHz would provide 45 degrees of shift. 2. Using EZNEC to add a stinger to resonate the antenna on 4 MHz, I find that's 11.5 degrees of straight element. 45 degrees plus 11.5 degrees is 56.5 degrees. 3. 90 - 56.5 = 33.5 degrees which is the "missing" degrees filled in by the impedance discontinuity. We can even estimate the ratio of the Z0 of the coil to the Z0 of the stinger to be 5.0. -- 73, Cecil http://www.qsl.net/w5dxp |
#5
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Poor Yuri.
Hanging his hat on Cecil, but now Cecil is getting the picture and yanking the rug out from under Yuri and his "missing electrical degree cutrrent taper and phase shift theory". It only took three or four years, but at least that's better than Fractenna. :-) Cecil Moore wrote: The whole point is that it doesn't differ. That's how my bugcatcher works. Here are the three parts to the answer. 1. The base-loading coil furnishes a delay equal to a certain number of degrees which is nowhere near zero degrees. Half of a coil self-resonant at 4 MHz would provide 45 degrees of shift. 2. Using EZNEC to add a stinger to resonate the antenna on 4 MHz, I find that's 11.5 degrees of straight element. 45 degrees plus 11.5 degrees is 56.5 degrees. 3. 90 - 56.5 = 33.5 degrees which is the "missing" degrees filled in by the impedance discontinuity. We can even estimate the ratio of the Z0 of the coil to the Z0 of the stinger to be 5.0. -- 73, Cecil http://www.qsl.net/w5dxp |
#7
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![]() wrote: Hanging his hat on Cecil, but now Cecil is getting the picture and yanking the rug out from under Yuri and his "missing electrical degree cutrrent taper and phase shift theory". Is the purpose of this newsgroup to smear individuals or to get to the technical facts? Nobody is 100% correct 100% of the time. The coil still occupies tens of degrees and still suffers a current taper because of that delay. It only took three or four years, but at least that's better than Fractenna. :-) I wouldn't laugh just yet, Tom. There's plenty of misconceptions on both sides. The delay through the loading coil is still tens of degrees, not anywhere close to the near-zero degrees that you have been asserting for years. The delay through a typical 75m bugcatcher coil appears to be about ~35 degrees with ~11 degrees of stinger. The "missing" ~44 degrees occurs at the impedance discontinuity between the coil and the stinger just as it does in my 450/50 ohm stub example. The 3 nS delay measured by you and the undetectable delay measured by W7EL were invalid measurements of delay. Standing wave current suffers zero delay all along a 1/2WL dipole whether it be in a wire or in a coil. The delay through a typical mobile loading coil on 4 MHz appears to be about 25 nS about half of what one would get in a straight wire equal to the wire used in the coil. -- 73, Cecil, W5DXP |
#8
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![]() Cecil Moore wrote: wrote: Hanging his hat on Cecil, but now Cecil is getting the picture and yanking the rug out from under Yuri and his "missing electrical degree cutrrent taper and phase shift theory". Is the purpose of this newsgroup to smear individuals or to get to the technical facts? I don't know. You and Yuri seem to be playing that game as much or more than anyone else. It's tough for both sides to behave and anyone to learn anything when all this strange stuff goes on, but this thread (in various forms) is very similar to the famous Fractenna threads. Nobody is 100% correct 100% of the time. .....and that obviously includes you as well as the rest of us. The key is to speak like friends and be honest rather than make this stuff into a long "Fractenna" thread. The coil still occupies tens of degrees and still suffers a current taper because of that delay. The coil does NOT have to occupy tens of degrees nor does it have to provide any current phase delay from end to end. It does have to have SOME delay and some current taper since it occupies space, but it can be so small we can't reliably measure it. The phase delay and current taper is tied to the load impedance on the open end of the coil and the construction of the coil, not to the electrical degrees. It appears you know that now. It only took three or four years, but at least that's better than Fractenna. :-) I wouldn't laugh just yet, Tom. There's plenty of misconceptions on both sides. My opinion is Lewallen and maybe a dozen others have a good handle on how it works. It appears you have gradually came more to center also, but I'm not quite positive how far. At least you no longer apperar to be saying the coil represents missing electrical degrees. The delay through the loading coil is still tens of degrees, not anywhere close to the near-zero degrees that you have been asserting for years. Be careful there. I have NOT been asserting that for years. My initial assertions years ago was there was no delay, but that was because I considered the inductor an inductance and was speaking of an inductance. Over two or three years ago I posted this: http://www.w8ji.com/mobile_and_loaded_antenna.htm which explains it is a matter of stray capacitance to the outside world compared to load inmpedance terminating the coil that causes deviations from a "perfect" coil. I also measured antenna current and posted the results at: http://www.w8ji.com/mobile_antenna_c...ts_at_w8ji.htm The delay through a typical 75m bugcatcher coil appears to be about ~35 degrees with ~11 degrees of stinger. The "missing" ~44 degrees occurs at the impedance discontinuity between the coil and the stinger just as it does in my 450/50 ohm stub example. I'd bet money I can build a coil that has very low phase delay. I'd also bet I could build one with larger phase delay **at the same point and frequency in the same system**. The problem is one of the stray capaciatnce from the coil to the outside world compared to terminating impedance of the coil. The 3 nS delay measured by you and the undetectable delay measured by W7EL were invalid measurements of delay. So you say. We have only your opinion or view on that, and that dosagrees with other people's opinions. You are not the final word. Standing wave current suffers zero delay all along a 1/2WL dipole whether it be in a wire or in a coil. The delay through a typical mobile loading coil on 4 MHz appears to be about 25 nS about half of what one would get in a straight wire equal to the wire used in the coil. Again it depends on the form factor of the coil. By altering the coil with no other changes it can be made to vary quite a bit. 73 Tom |
#9
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wrote:
The coil does NOT have to occupy tens of degrees nor does it have to provide any current phase delay from end to end. The coil has to obey the laws of physics. Most real-world 75m loading coils occupy tens of degrees of the mobile antenna. Your assertion that nearly 100% of the coils link nearly 100% of the total flux is unrealistic. The effect of coil flux linkage approximately doubles the VF from e.g. ~0.02 to ~0.04, not from 0.02 to near 1.0, as you assert. A speed up by a factor of 2 is a lot more realistic than a speed up by a factor of 50. The phase delay and current taper is tied to the load impedance on the open end of the coil and the construction of the coil, not to the electrical degrees. Reference my stub example which contains *NO COIL*. There is a *short circuit* looking into the stub. ---30 deg 450 ohm line---+---11 deg 50 ohm line---open The 450 ohm line provides 30 deg of phase shift. The impedance discontinuity at '+' provides 49 deg of phase shift. The 50 ohm line provides 11 deg of phase shift. All this happens without any coil in sight. A very similar thing happens with a 75m mobile antenna. The base loading coil provides tens of degrees of phase shift. The impedance discontinuity between the coil and the stinger provides tens of degrees of phase shift. The stinger provides tens of degrees of phase shift. You seem to have taken the tens of degrees of phase shift in the coil and transferred those number of degrees to the impedance discontinuity. That is a mistake based on the presuppositions of the lumped circuit model. Asserting such is akin to asserting that there is no delay in the 450 ohm line section in the stub above. My opinion is Lewallen and maybe a dozen others have a good handle on how it works. It appears you have gradually came more to center also, but I'm not quite positive how far. At least you no longer appear to be saying the coil represents missing electrical degrees. For months I have been saying that the mobile antenna doesn't have to be 90 degrees long. It has been a couple of years since I said that the coil represents missing electrical degrees. You know that but still attempt through inuendo to make hay from a mistake I made two years ago. I correct my mistakes in real time. It doesn't matter what I said two years ago. And you object when someone does that to you. For months I have been saying that the coil delay is what it is and nobody has made a valid measurement of that delay. The best information available on that subject (to the best of my knowledge) is Dr. Corum's paper at: http://www.ttr.com/TELSIKS2001-MASTER-1.pdf I'd bet money I can build a coil that has very low phase delay. I'd also bet I could build one with larger phase delay **at the same point and frequency in the same system**. We are not discussing how smart or tricky you can be in producing one special case coil. We are discussing real-world 75m bugcatcher coils. Whatever you assert has to apply to all coils, not one special case. It doesn't matter that you can create one coil that matches your assertions about all coils. That's like asserting that all cars are white and producing one white car as proof. W5DXP wrote: The 3 nS delay measured by you and the undetectable delay measured by W7EL were invalid measurements of delay. So you say. We have only your opinion or view on that, and that disagrees with other people's opinions. You are not the final word. It's my view based on all the facts. If I'm wrong, I will freely admit it and correct my misconceptions. However, at the present time, I think I have proven that standing wave current on a standing wave antenna cannot be used to measure the delay through a wire, much less through a coil. You and W7EL both used standing wave current, with its unchanging phase, in your phase measurements. W7EL says that EZNEC agrees with me on that point. So he is in the position of either disagreeing with EZNEC or admitting that his phase measurements though accurate were meaningless. EZNEC proves that standing wave current phase cannot be used to measure phase shift through a wire, much less through a coil. As recently as last month, you appeared not to know that fact as illustrated by this previous posting. ************************************************** ****************** Cecil Moore wrote: I made self-resonance measurements on loading coils and standing wave current measurements on a 6m dipole. W8JI said my measurements were in error. W7EL said my measurements agreed with EZNEC. Replying to my measurements, here are your words and W7EL's words: W8JI wrote on 3-16-06: Your measurements are probably wrong. ... After we resolve the error in current, we can move on. W7EL replied on 3-16-06: The measurement looks good to me. The phase is exactly what EZNEC predicts -- constant along the wire. ************************************************** *************** W7EL agrees that the phase is "constant along the wire". How can a signal with constant phase be used to measure phase shift through a wire? or through a coil? After a year, there is still no answer provided for this technical question. The answer provided by EZNEC is at: http://www.qsl.net/w5dxp/travstnd.GIF Standing wave current suffers zero delay all along a 1/2WL dipole whether it be in a wire or in a coil. The delay through a typical mobile loading coil on 4 MHz appears to be about 25 nS about half of what one would get in a straight wire equal to the wire used in the coil. Again it depends on the form factor of the coil. By altering the coil with no other changes it can be made to vary quite a bit. We are talking about 75m bugcatcher coils, Tom, not one special case coil engineered by you. If your assertions fail for a 75m bugcatcher coil, then they fail in reality. You assertions have to be valid for all cases or else they are invalid. Finding one special case that agrees with your assertions, e.g. your previous toroidal coil measurement, may boost your ego but doesn't really matter one iota in the overall scheme of technical fact. -- 73, Cecil http://www.qsl.net/w5dxp |
#10
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![]() wrote in message ups.com... Poor Yuri. Hanging his hat on Cecil, but now Cecil is getting the picture and yanking the rug out from under Yuri and his "missing electrical degree cutrrent taper and phase shift theory". It only took three or four years, but at least that's better than Fractenna. :-) "Brilliant" Tom! putting words in my mouth, twisting and trying to weasel out of technical arguments by spewing personal crapattack. Argument is about you claiming current in a loading coil is ALWAYS the same, which has been shown to be WRONG and crap on your web site is still proof of it. You can make up stories about my theories, it will not prove you RIGHT. Where did you get your "engineering" degree Tom and by what rights you use "JI Engineering"? That smells with fraud!!! Care to continue with bul****? Grove up or get help! 73 Yuri |
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