RadioBanter - View Single Post

May 5th 06, 01:32 PM posted to rec.radio.amateur.antenna

wrote:
I would assume that because the feedline current is common-mode (the
same in both conductors), it will usually travel at the velocity factor
of a wire in air rather than the feedline velocity factor, though I do
not know this.

Seems like a reasonable assumption given skin effect and the
outside braid of the coax. Common-mode current also, no doubt,
forms standing waves with current minimums and maximums 1/4WL
apart. A choke would be most effective at a standing wave
common mode current maximum point.
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73, Cecil http://www.qsl.net/w5dxp