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Old March 26th 06, 10:26 PM posted to rec.radio.amateur.antenna
Tom Donaly
 
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Default Current through coils

Cecil Moore wrote:

Tom Donaly wrote:

What about figure 2, Cecil?



Figure 2 suggests that any coil with a delay over 15 degrees
should be analyzed by discarding the lumped circuit model
and instead using the distributed network model. Every coil
I have talked about on this thread has a delay greater than
15 degrees. 15 degrees of impedance transformation will transform
50 ohms into 54+j120 ohms with a difference in SWRs of 7 to one.
Does that really sound like a reasonable reason for keeping the
lumped-circuit model?

Roy just said in another posting that the reflection model
will solve all the problems that the lumped circuit model
will solve. It just gets clumsy as far as the math goes.

It is interesting to watch the gurus retreat into fantasy
where they were only ever talking about tiny point inductances
to start with. Anyone who has been following this argument
over the years knows otherwise.


Figure 2 shows that the authors considered their model to be
that of a shorted stub to replace the inductance of their Tesla
coil. They didn't say that a coil of wire is a shorted stub,
only that it performs the same function as one in the calculations.
You're waffling and trying to slick your way out of an embarrassing
situation again, Cecil. O.k., I'll accept the shorted stub
substitution. Heck, I'll even accept a solution involving
op-amps, (provided you don't use it in transmit mode). What I won't
accept is pretending a long hank of transmission line with a load
at one end performs the same impedance transformation in the same way
as a coil of wire.
73,
Tom Donaly, KA6RUH