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Old March 26th 04, 10:06 PM
Tom Bruhns
 
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Cecil Moore wrote in message ...
....
The SWR circle (at the frequency of maximum reactance) will pass through
the 2500+j2500 ohm point. Do you disagree?

The reactance arc (at the frequency of maximum reactance) will pass
through the 2500+j2500 ohm point. Do you disagree?

ERGO: The SWR circle will be tangent to the reactance arc at the
2500+j2500 ohm point no matter what Z0 is being used. Do you
disagree?


that specific example, using a reference impedance of 50 ohms...

magnitude of rho for 2500.00+j2500.00 = .9801999804
magnitued of rho for 2500.25+j2500.00 = .9801999801
magnitude of rho for 2500.50+j2500.00 = .9801999800
magnitude of rho for 2500.75+j2500.00 = .9801999801
magnitude of rho for 2501.00+j2500.00 = .9801999804

The point of tangency to an SWR circle for the +j2500.00 arc is
therefore NOT at 2500.00+j2500.00. It will be much more obvious if
you recalculate things at a higher reference impedance, say 1000 ohms.
Then following the +j2500 reactance arc, mag(rho) reaches a minimum
when Z is about 2692+j2500. And in any event, I think it highly
unlikely that the antenna's resistance when the reactance peaks at
2500 ohms will be exactly 2500 ohms as well.