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Old March 21st 06, 01:29 AM posted to rec.radio.amateur.antenna
 
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Default Current through coils


Cecil Moore wrote:
Certainly, no repugnance or disrespect intended. Roy is presently
in the unenviable position of agreeing with (EZNEC and me) or
disagreeing with (EZNEC and me). Hint: rhetorical questions
require no answer.
73, Cecil http://www.qsl.net/w5dxp


I'm not sure what that is all about, but Cecil....there are over 550
posts in this thing now.

Can you state in a few clearly written lines what you have learned or
concluded? If that is too involved, that's OK.

I'm just trying to understand what you point is in all of this, and
where your head is at after all the posts.

My conclusion for short mobile or fixed location loaded antennas is:

1.) If a loading coil has compact form and is terminated in a
capacitance that presents a reasonably low impedance compared to
inductor capacitance to the outside world, current taper will be
minimal. As a matter of fact, it can be immeasurable.

2.) Current taper and phase shift do not correspond to the electrical
degrees the loading coil "replaces", except as the physical size of the
loading coil might increase stray capacitance to the outside world.

3.) Phase shift of current is anything from zero to a reasonably small
number of degrees, and does not correspond to the electrical degrees
the inductor replaces.

4.) There are at least two ways to get a good answer. One is by a
circuit model with enough L and C sections, the other is with a wave
theory approximation. Both models have limits.

I think that pretty much is it. What did you conclude? Can you get it
into a few clear words?

I just want to see how far apart everyone still is.

73 Tom