In a message dated 2/23/05 11:26:25 AM Central Standard Time, g8gsq@ic24.net
writes:
I don't think there is much difference between a dummy load and antenna,
that
wasn't the thought behind my post. In practice there's around 2% harmonic
voltage at the output, so the difference might not be entirely negligible if
the antenna has a bad match at harmonic frequencies.
*** In that case there should be at least a 2% difference in measurements
between the dummy load and the antenna. And I covered that fact when I
mentioned that there could be a difference in readings if the antenna was a
highly
reactive load, which it should be at the harmonic frequencies....
*** Of course if your antenna is the multiband trap type and you are
broadcasting at 160 and have harmonics at 80, 40, 20 and 10, I guess you could
efficiently radiate the harmonic energy also. Something I could never
understand
why someone would want to do.....
I'm going to have to go away and think some more - I'm struggling to find
ways
of putting things into words coherently.
One thought though - at the plate there's plenty of harmonic voltage/current
that isn't present when you probe the tank circuit with the tube cold. The
dip in total anode current might not coincide with a purely resistive plate
load at the fundamental frequency.
*** I guess that's possible, but wouldn't the harmonic energy be an exact
multiple of the base frequency?
***Regards,
***Dennis O.
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