I have a Commander HF-2500 Magnum, with a pair of 3CPX800's. Great amp.
It has one quirk, and only on 15 meters. If the amp has been dormant for a
while, the output power is initially low: about 1100 watts. Key down it
gradually rises up to 1500 watts over about 10 seconds. After that, if I
intermittently transmit, at least every 5 minutes, it will stay at 1500
watts. Only after being idle for ~30 minutes will it go back to the low
output state.
My thought is that something in the input pi network is heating up.
However, I have accurate SWR/power meters on both the amp input and amp
output. Neither the input power nor SWR is changing as the output power
rises. As the power rises, the grid current drops, but the plate current is
unchanged. Again, this is only on 15 meters.
Suggestions ?
73,
Steve, N2IC
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|