On Wednesday, August 22, 2012 7:47:07 PM UTC-5, amdx wrote:
I thought a resonant antenna was resistive without any reactance.

Consider a transmission line with standing waves. There is a point every 1/2WL where the impedance is a low "resistance without any reactance". That is the point where the standing wave voltage is in phase with the standing wave current. A 1/2WL dipole is a standing wave antenna with an SWR on the antenna of approximately 20:1. At the center feedpoint, the standing wave voltage is in phase with the standing wave current so the feedpoint impedance is "resistive without any reactance".

If you look at the current and voltage distribution on a standing wave antenna you will find that it looks just like the current and voltage distribution on a transmission line with reflections.

http://www.learn-about-electronics.c...d-voltage.html

http://vsagar.com/2012/02/23/voltage...ipole-antenna/
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73, Cecil, w5dxp.com