Roy Lewallen wrote:
So your math is good only for an ideal antenna? That's a sad state of
affairs.

Heck, I'll just supply you with ten dimensions and virtual photons and
see just how well your math works. :-) This discussion has very little
to do with math equations. The orbits of the planets got along just
fine before man ever walked the earth and came up with the math to
explain them. Reality rules! Here's what Einstein said:

"One thing I have learned in a long life: that all our science, measured
against reality, is primitive and childlike ..."

Ok, let's suppose I build an ideal antenna that's about 33 feet high,
with a feedpoint impedance of 35 - j370 ohms at 3.8 MHz. Choose an
inductor value and let me know what the output:input current ratio would
be for that inductor at the base of the antenna. Assume that the
inductor is physically very small.

Why? The argument is/was about bugcatcher coils which are NOT small.
Who uses a physically small toroid in his center-loaded mobile antenna?
Not that it wouldn't be an interesting experiment.

Roy, it appears to me that you are trying to win the last battle after
the war is over, like the South did weeks after Lee surrendered. Please
feel free to proceed with whatever mission that you are trying to complete.
Whatever it is, it is a diversion from the original argument based on W8JI's
alleged assertion that the current magnitude and phase doesn't change
through an HF mobile antenna's loading coil. That argument has been lost.

It appeared that you jumped in and defended W8JI and called everyone
who disagreed, "ignorant engineers", or something to that effect. The issue
between you and me was settled when you posted that you had no argument with
current magnitude and phase changes through HF mobile antenna loading coils.
(Now if we can just get W8JI to agree with you.)
--
73, Cecil http://www.qsl.net/w5dxp



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Roy, W7EL wrote:
"---feedpoint impedance of 35-j370 at 3.8 MHz. Choose an inductor value
and let me know what the output : input current ratio would be for that
inductor at the base of the antenna. Assume that the inductor is
physically small."

I`ll assume the inductor has no resistance, loss or radiation.

No loss or radiation means the inductance only delays current in the
antenna circuit by the phase angle impedance makes with resistance in
the circuit.

We need 370 ohms of inductive reactance to counteract the capacitive
reactance of the too short antenna. That calculates to 10.926
microhenry.

The current into the resonant antenna circuit is E/R = E/35

The current into the too short antenna alone is E/Z = E/ 371.65

The output : input ratio of the inductor is very nearly one because the
coil is lossless and its size is insignificant in terms of wavelength.

Best regards, Richard Harrison, KB5WZI

Hm. Let's suppose the inductor had a loss resistance of, say, 35 ohms
(equal to the resistive part of the antenna input Z). What would the
ratio be then? This is assuming the loss is dissipative and not "loss"
due to radiation.

Roy Lewallen, W7EL

Richard Harrison wrote:
. . .
The output : input ratio of the inductor is very nearly one because the
coil is lossless and its size is insignificant in terms of wavelength.