[Elecraft] KPA-1500 Power Output Variation

[Jack Brindle]

Jim;

It would be interesting to see the source of the variance. You might insert the Bird between the transceiver and the KPA to see if there is any variance there.

The amplifier has fixed gain - it has no ability to vary its gain during transmission other than a protective pad that is inserted when problems are detected. The power is not
changing enough for that to be indicated, which makes me wonder just where the actual variance comes from.

73!
Jack, W6FB


> On Aug 24, 2019, at 3:58 PM, Jim McCook <w6ya at cox.net> wrote:
> 
> Don,
> 
> I'm seeing the power changes on the front panel of the amp, on the Utility, and on the Bird external to the amplifier.  The Bird 2500w slug is about 40 years old, so it probably needs recalibrating.  Still, I can see the relative differences at all 3 spots.  There is no fault in the amp when it hits the high power level around 1700w.
> 
> My attenuator idea was to put it at the input of the transmit section of the amp, out of the receive line..... in the same place as the built in attenuator.  It still seems to me it would help for reasons I mentioned before.  With low drive levels the output is most sensitive to relatively small changes in drive.  I think the idea of running the K-3 closer to rated output is still desirable.
> 
> Thanks, guys, for all the input.
> 
> Jim W6YA
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