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Old October 22nd 06, 06:45 PM posted to rec.radio.amateur.antenna,alt.ham-radio.hf
Cecil Moore Cecil Moore is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 1,614
Default Hf Antenna Question

Ian White GM3SEK wrote:
Across the whole 1-30MHz band, the bunched choke behaves as an almost
perfect L-C circuit, free from any unwanted resonances.


One additional point. If the above were true, as the
frequency is increased, the phase angle of the coiled
choke impedance would drop from ~90 degrees to zero at
the self-resonant frequency, and then rise back to ~-90
degrees and stay there. But that's not what happens.

In every single case, the phase angle rises toward -90
degrees *and then decreases* as the 1/2WL self-resonance
point is approached. That is a clear indication of transmission
line effects. A lumped circuit simply doesn't act that way.
--
73, Cecil http://www.w5dxp.com