So, you've retracted your prediction. What's your new one, then?

Roy Lewallen, W7EL

Cecil Moore wrote:
Roy Lewallen wrote:

I did read what you said. You said that it wouldn't exhibit a phase
shift if placed at a current maximum.


I'm sorry, there is a misunderstanding that is my fault. When I say
"current is the same.", I'm implying magnitude only. That's a
convention left over from my college days and may not be a
convention any longer. If I said anything at all about phase, I
used the word, "phase", in my posting. So I will stop omitting
the word, "magnitude", when I am talking about magnitude.

So do a system reset on what you think I said. There is always a
phase shift through a real-world inductor. Whether it can be
measured accurately is another matter. When I said: "If the
current maximum point is located in the middle of a coil, the
current (implied magnitude) in and out of a coil will be equal.",
I was implying current magnitude only. I didn't imply or say anything
about phase unless I used the word, "phase" in the sentence.

I also have not said anything about the phase of the currents into
and out of your toroidal inductance except to say it replaces
approximately 18 degrees of antenna.

The current at the base of a short vertical antenna is at its maximum
there. So now if you're saying that it *won't* exhibit a phase shift
if placed at the base of a short antenna, let's try this.


As you can see above, I never said anything like that.

Suppose I remount my antenna to eliminate the shunting effect of the
mounting, and do my measurements at 3.8 MHz as before. Suppose the
base input Z is, say, 35 -j380. You choose any inductor value you'd
like, that will best illustrate your method, and tell me what output
to input current ratio to expect.


I am still leery about your ability to separate small phase shifts
from noise. We need to make the inductor large enough to ensure
the phase shift measurements are above the noise level.

I have no disagreement that a "bugcatcher" coil, or any coil of
physically significant size, will exhibit a phase shift and magnitude
change of current from one end to the other.


Huh?????? I thought that was what the argument was all about. What
triggered this whole discussion was W8JI's alleged assertion that
a loading coil like a bugcatcher doesn't affect the current at all.

Where we disagree is that you believe that a physically very small
inductor will also exhibit this. I don't.


The effect of a very small inductor may be too small to measure in
the presence of strong fields and noise. Ask yourself, at exactly
what value of inductor does the phase shift completely disappear?
+j1? +j10? +j100? +j1000? What is the crossover point from some
phase shift to zero phase shift? Can you measure a phase shift of
0.1 degree at HF? Zero phase implies faster than light propagation
through the coil.
--
73, Cecil, W5DXP