[Elecraft] Power drop off driving an amplifier (Alpha 78)

[Mark C. Killmon]

Using firmware release 3.11 (and it seemed, with 2.78 also) I notice a drop
off in power on SSB after a couple seconds, which then stabilizes at a lower
level "for the duration." The first few seconds of the first transmission
seem to be at full output, judging by the amplifier output, around 1200W in
this case. After transmitting, the power drops to about half that level and
stays stable, until the next power cycle of the rig. CW doesn't seem to
exhibit this behavior. Driving the amp with my other rig, I don't see this
occur. The SWR is low, and stable into the amp. I seem to recall some
mention of this on the list, but thought something was tweaked in 3.11 to
affect it. It sounds a bit like the slow ALC response I've seen discussed,
but I am not using the ALC out to the amp, since it's designed for above 100
watt drive levels from back in the tube final days.

 

Thanks for any thoughts. Just a month in or so (SN2861) and I'm finding this
to be an amazing rig. 

 

73, Mark

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