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Roy Lewallen wrote:
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. Well, the subject was 75m bugcatcher loading coils", so your choice of a "physically small coil" was already somewhat of a straw man. And Roy, you made the same mental blunder in your measurements that Tom made. I have explained it to you before and you have so far refused to listen or even read my postings so here it is once again. Everyone is invited to think about what I am saying and agree or attempt to refute it. Point by point: A 1/4WL monopole over ground is known to be 90 degrees long. The phase of the current changes by only a few degrees from feedpoint to tip. How much phase shift (delay) in the current would we measure in 30 degrees of a monopole? Answer: Only one or two degrees. Why is there only a small number of degrees of phase shift (delay) in the current in 30 degrees of monopole? Because it is *standing-wave current* that is being used for the measurement and the phase barely changes over the entire monopole length. EZNEC agrees. A 1/4WL monopole has 5.67 degrees of phase shift in the current from segment 1 to segment 33 even though the antenna is 90 degrees long and therefore has an inherent delay of 90 degrees from feedpoint to tip. Standing-wave current cannot be used to measure the delay through a wire. So can that same *standing-wave current* be used to measure the phase shift (delay) through a coil? Answer: No, standing wave current cannot be used to measure the phase shift (delay) through a wire or through a coil because the phase hardly changes no matter how long is the delay through the coil or through the wire (assuming coil and wire are 1/2WL). Roy and Tom both used standing-wave current to try to measure the delay through a coil. Such an attempt is doomed to failure for obvious reasons and is a violation of the scientific method. STANDING WAVE CURRENT CANNOT BE USED TO MEASURE PHASE SHIFTS IN A WIRE OR IN A COIL BECAUSE STANDING WAVE CURRENT HAS ESSENTIALLY NO PHASE SHIFT! THERE IS NO PHASE INFORMATION IN STANDING WAVES! There is absolutely no correlation between the phase of standing-wave current and the delay through a coil or through a wire. What is the phase shift through a coil at self-resonance? Answer: It is known to be 90 degrees at the first self- resonant frequency, i.e. 180 degrees end-to-end. What is the measured phase shift through that self-resonant coil at the self-resonant frequency using standing-wave current? Answer: That measured phase shift will be very close to zero, nowhere near the known 90 degrees. -- 73, Cecil http://www.w5dxp.com |
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