In a message dated 97-06-05 19:20:06 EDT, you write:
<< Hi Terry,
> 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.
So a external ALC circuit such as one in a AB1 amp is going to feed back to
the exciter and cut the drive from the exciter quicker ?
<< 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.
This "leading edge" is still gonna be there with the alc circuit from the
amp.
<<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
>>
I still suggest, to not overdrive a AB1 amp...use the power control on the
exciter.
I think some people are too close to the forest to see the trees.
Terry - W6TG
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