Cecil,

I gave you a very specific reference to demonstrate your supposition was
incorrect. You came back with nothing but, "Because I say so." You have
not offered one shred of backing for your constant Vf argument.

And it is up to ME to further prove something?

I don't think so.

73,
Gene
W4SZ


Cecil Moore wrote:
Gene Fuller wrote:

I will retain the entire message below, so that I am not accused of
misattribution.


Gene, to the best of my knowledge, you have never
misattributed anything.

Where did you get this idea that the velocity factor is constant?


The equation for velocity factor includes coil diameter,
turns per inch, and wavelength. Keeping the coil diameter
constant, the turns per inch constant, and the wavelength
constant should ensure that the velocity factor is constant.

Specifically, why is the velocity factor of a resonant coil the same
as the velocity factor of a significantly shorter coil? It is pretty
well accepted that the inductance of coils does not scale linearly
with the length of the coil. Therefore any arguments about based on
direct calculation of Vf from L and C would seem to fail to support
your model.


You are obviously mistaken. If you increase the L by lengthening
the coil, you have also increased the C by the same percentage.
The L and C for any unit length are the same no matter how long
the coil or transmission line is.

" . . . an approximation for M has been determined by Kandoian and
Sichak which is appropriate **for quarter-wave resonance** and is
valid for helices . . ."


Yes, but if one doesn't change the frequency or the diameter or
the turns per inch, the approximation should hold since nothing
in the VF equation changes by shortening the coil. One should be
able to shorten or lengthen the coil andmaintain the same VF.

Seems it is up to you to prove what you are saying. Please prove
that the ratio of L to C ratio of a coil changes with length. That
should be an interesting proof.