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Current through coils
John Popelish wrote:
The only way I can see to do it is to go outside the coil and look at how the standing current nodes move. Standing wave phase is with respect to position, not time. Well John, you are obviously not up on the latest techniques. (But neither am I.) -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
John Popelish wrote:
"Did you hear what he said about your wife?" Whatever he said is probably true. My ex-wife made off with $3 mil of my hard-earned dollars in 1984. I've never trusted a female since. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Roy Lewallen wrote:
"Phaseless signals". What an imaginative creation. Well not really, if you think about it, the phase of a DC signal can be considered to be zero everywhere. The phase of a standing wave current *is* zero everywhere on a 1/2WL thin-wire dipole. Seems to me, a standing- wave current indeed does have a lot in common with a DC current. But that might just be a coincidence. :-) -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Cecil Moore wrote:
John Popelish wrote: "Did you hear what he said about your wife?" Whatever he said is probably true. My ex-wife made off with $3 mil of my hard-earned dollars in 1984. I've never trusted a female since. This factoid brings several apparently unrelated things into focus for me. |
Current through coils
John Popelish wrote:
Cecil Moore wrote: Whatever he said is probably true. My ex-wife made off with $3 mil of my hard-earned dollars in 1984. I've never trusted a female since. This factoid brings several apparently unrelated things into focus for me. Remember the Koala Pad? I was VP of Engineering and a couple of those patents are in my name. Koala Technologies could not survive the president's divorce and my divorce at the same time. The venture capitalists pulled the plug. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Reg wrote:
"Wanna bet?" Don`t bet against Reg. Phase shift aling the coil plus the phase shift along the conductors DOES add up to 90 degrees when the antenna is 1/4-wave resonant. Recall the purpose of the coil is electrically to make the too-short whip appear full-sized. The assembly is resonant when worked against the earth. Its plus and minus 90-degree reactances are equal in magnitude to each other. Best regards, Richard Harrison, KB5WZI |
Current through coils
Cecil,
I never in my wildest dreams said anything about Tom's measurements. (Perhaps in your dreams.) I don't believe that Tom set up a simple standing wave antenna and then tried to measure the phase of the standing wave. You seem to have forgotten, but a few days ago you were vehemently arguing that the bugcatcher coil in your mobile antenna must have X amount of phase shift. My comments, which may have proven too successful, dealt only with the basic fundamental properties of waves. That's the sort of thing that everyone should have learned in elementary school, but such knowledge seems to be fleeting for some people. 73, Gene W4SZ Cecil Moore wrote: wrote: It sounds like Cecil is trying to find a way to make his theory fit despite the fact that models and measurements show the phase shift is zero, and demanding I agree with his unusual theories like current that doesn't flow, phaseless signals, and in his latest post antennas behaving like dc circuits. Again, it is not my theory. It is the distributed network model known to succeed when the lumped-circuit model fails in the presence of standing waves. There is no useful phase information left in a standing wave current. DC current and standing wave current are equally 100% ineffective at measuring the delay through a coil. I have asked this technical question multiply times: How does one use a signal with unchanging phase to measure the delay through a coil? The answer is that one cannot. All that aside, it appears the main argument is Cecil's theory requires measuring current that doesn't flow ... No, using a signal with unchanging phase to try to measure delay is your main argument, not mine. I know it is foolish to measure a current with unchanging phase. Any phase measurement is meaningless. cos(kz)*cos(wt) doesn't possess phase information. One can tell that from the formula. Unlike you, Gene Fuller understands the meaning of those standing wave equation terms. Gene Fuller wrote: In a standing wave antenna problem, such as the one you describe, there is no remaining phase information. Any specific phase characteristics of the traveling waves died out when the startup transients died out. Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen again. The only "phase" remaining is the cos (kz) term, which is really an amplitude description, not a phase. Do you disagree with what Gene had to say? "PHASE IS GONE. KAPUT. VANISHED. CANNOT BE RECOVERED. NEVER TO BE SEEN AGAIN." In other words, one cannot use standing wave current to measure the delay through a coil. Delay doesn't exist in a standing wave current, i.e. "PHASE IS GONE." The worse part of that is he is demanding I answer something I cannot answer ... There's nothing wrong with admitting ignorance. Just please cease trying to disguise your ignorance as some technical fact. When are you going to correct the technical errors on your web page? 75m mobile bugcatcher loading coils possess a velocity factor of approximately 0.0175. They are about 6.6 inches long. The delay through that coil is ~0.128 wavelength at 4 MHz. That's a delay of 32 degrees. That's how much electrical length the coil is occupying when it is used on 4 MHz. |
Current through coils
"Gene Fuller" wrote: I never in my wildest dreams said anything about Tom's measurements. Of course not and I certainly didn't mean to imply otherwise. What you said was *objective and impersonal*, applicapable to anyone's measurements and also applies directly to Tom's earlier measurements. I don't believe that Tom set up a simple standing wave antenna and then tried to measure the phase of the standing wave. Maybe we should ask him. As I understand it, both Tom and Roy set up a simple loaded 1/4WL resonant *standing wave* monopole and measured the standing wave current at the bottom and top of the coil. EZNEC could have told them that they wouldn't measure any phase shift around the coil or anywhere else around along the antenna.. It's an easy mistake to make to look at the current displayed by EZNEC and picture that current flowing from the feedpoint to the tip while being 100% radiated in the process so the current falls to zero at the tip of the antenna. As we know, those are not the technical facts. The reflected wave is a large percentage of the forward wave. As seen from the graphic at: http://www.qsl.net/w5dxp/3freq.gif that standing wave current can have virtually any magnitude but has a phase that comes only in near-zero or near-180 degrees increments. I've been asking how to obtain phase information from a standing wave current. Nobody has answered. -- 73, Cecil, W5DXP |
Current through coils
Gene Fuller wrote: Cecil, I never in my wildest dreams said anything about Tom's measurements. (Perhaps in your dreams.) I don't believe that Tom set up a simple standing wave antenna and then tried to measure the phase of the standing wave. You seem to have forgotten, but a few days ago you were vehemently arguing that the bugcatcher coil in your mobile antenna must have X amount of phase shift. My comments, which may have proven too successful, dealt only with the basic fundamental properties of waves. That's the sort of thing that everyone should have learned in elementary school, but such knowledge seems to be fleeting for some people. Roy measured a real antenna for phase, I measured a moblile antenna for current. http://www.w8ji.com/agreeing_measurements.htm |
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