[AMPS] Tetrode Amp articles needed
Thu, 5 Jun 1997 15:34:13 +0000
> I would use the power output control that is on most all the transceivers
> these days to not drive the AB1 amp into grid current.
> Terry - W6TG
I would too, if it worked properly. Unfortunately, those controls
more often than not allow the exciter to overshoot on leading edges.
I've measured ICOMs that produce 300 watts PEP when set to 25 watts
output during the leading edge on SSB. My IC-706 hits 150 watts plus
on some bands (no matter what level I set the power control at), my
FT-757 hits nearly 180 watts, but my IC 751A is OK.
A friends 950SDX snacks the PA with almost 300 watts on leading edges
with the power set at 100 watts.
The problem is the time constant in the internal power control system
(generally ALC derived from a directional coupler at the rigs
output) is slower than the rise time of the envelope.
73, Tom W8JI
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