Cecil Moore wrote:
"Michael Coslo" wrote:

Back on topic now. Was there ever any correlation between the
measurements made by Cecil and Yuri with the information and tests
performed by Tom W8JI? I had asked the question a couple times, but have
no answer yet. Maybe the message got lost.


Might have been when I was out of town. Except for a
single toroidal coil anomaly, all of the measurements
show a different magnitude of current at the two ends
of the coils. Most of my measurements have been at
the self-resonant frequency of a loading coil.

That isn't the design frequency though, is it?

A 75m mobile bugcatcher coil is part of a standing wave
antenna with near-equal forward and reflected currents
flowing in opposite directions (phasors rotating in
opposite directions). As a result, the standing wave
current on the antenna has essentially the same phase
as the source current all up and down the antenna
*whether a loading coil exists or not*. Standing wave
current on a mobile antenna cannot be used to measure
phase shift or delay through a wire or a coil.

That standing wave current is of the form,
I = Io*cos(kx)*cos(wt), and cannot be used to determine
phase shift. So the major measurement mistakes were
not in the magnitudes, which are relatively easy to measure,
but in the phase-delay measurements, which were invalid.

The major conceptual mistake concerns standing waves,
not coils. It appears that some people didn't even realize
that they were dealing with a standing wave current on a
standing wave antenna.

The best estimates of actual delays through the coils seems
to come from the Dr. Corum IEEE paper where formulas
are given for the VF and Z0 of a coil. For the particular
coil being modeled in EZNEC, the VF formula yields
~0.02, or about 37 degrees for a 6" long coil on 4 MHz.


I'm not sure I have this straight. I think I understand Tom's info, yet
this has me completely baffled.

Would the short answer be that you do not find any correlation?

- 73 de Mike KB3EIA -