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April 30th 06, 04:16 PM posted to rec.radio.amateur.antenna

Cecil Moore wrote:

wrote:

TE, TM, or TEM a small loading coil cannot behave very much like a
transmission line.

We are not discussing small coils, Tom. We are discussing big
honking 75m bugcatcher coils. Why do you guys always retreat
from the real world into the area of "small" coils?

If you read the Corum paper carefully, you see he clearly states it is
an approximation or solution for a coil under the very special
condition of being self-resonant.

False. He clearly states that the VF and Z0 were established at
the self-resonant frequency and that those values hold as long
as the coil pitch, coil diameter, and frequency remain unchanged.
That's exactly what I have done using EZNEC models.

He is working on Tesla coils, not loading coils.

The first words in the title are, "RF Coils, ...". Figure 2
looks just like a 75m bugcatcher system with a top hat. A
75m bugcatcher coil is a helical resonator that brings the
antenna system into resonance.

He has a litmus test for RF coils. If the coil dimensions
pass the litmus test, then his VF and Z0 equations are known
to be valid within 10%. A 75m bugcatcher coil passes that
litmus test by a 100% margin.

A self-resonant coil is 90 degrees long. Dr. Corum says the
lumped circuit model doesn't work until the coil is trimmed
down to 0.167 of that length. Seems you have proven that to
be true.

Notice also how Cecil misquotes to make a point. The Vf I measured on
80 meters for a large bug-catcher style coil was actually .5 compared
to spatial length, not 1.0

Sorry, my memory was faulty on that one but 0.5 is still 1000%
different from the value predicted by Dr. Corum's VF equation
and flies in the face of known technical facts about coils.

On the other hand Cecil has measured virtually nothing, Yuri has
measured nothing, ...

Which is better, Tom. Valid science or invalid measurements? You
still haven't answered my question as to why you don't just
assert that a 1/4WL monopole is zero degrees long since there is
zero degrees of phase shift in the standing wave current phase
from end to end in the antenna. Heck, you can even prove that
a 1/2WL thin-wire dipole is zero degrees long using the same
measurement techniques that you used on a coil.

... and Harrison probably hasn't even owned a bug catcher
coil being a technician class license holder.

Instead of belittling his ham license, how about you compare
your technical degrees to "Harrison's"?

Tom sure hit the nail on the head this time, didn't he, Cecil.
When are you guys going to do your own experiments and
measurements. Yuri at least threatens to do them. You just
use a fast mouth and a few hick rhetorical techniques to get
someone - anyone - to go along with you. A man can justify just
about anything with his mouth, including CFA antennas and their
kin, but providing repeatable experiments and measurements
is something else again... ain't it.
73,
Tom Donaly, KA6RUH

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