OK,
With a dummy load - actually a 500W Bird 30dB attenuator - the
displayed power out came up to 78W.
I tried adjusting the bandpass filter - it was already spot on. They
use one filter for 40M and 30M,
and you go back & forth between the two. It was already perfectly
peaked & tweaked.
What about the KPA100? I turned the power down to 10W, taking it out
of the circuit.
20M - 9.6W
30M - 10.23W
With power set to 40W:
20M - 41.7W
30M - 42.5W
With power set to 60W:
20M - 56.8W
30M - 62.5W
With power set to 80W:
20M - 71W
30M - 77.6W
With power set to 100W:
20M - 78.6W
30M - 91.7W
With power set to 110W:
20M - 78.6W
30M - 98.5W
I suspect that the problem is in the KPA-100. Maybe a wrong value in
the LPF?
Power out with control set fully clockwise, into the dummy load,
measured by the Telepost:
80M - 120W
40M - 104W
30M - 97.7W
20M - 79.4W
17M - 98.3W
15M - 88W
10M - 74.5W
Interesting, according to the KPA100 manual, 20M and 17M share an LPF.
If it was out of whack, I'd expect 17M to be MORE
effected than 20.
- Jerry, KF6VB
On 2024-03-16 09:10, Joe Subich, W4TV wrote:
But before that, I should redo the test with a dummy load.
Yes.
And it's not just gain decreasing with rising frequency, because it
does 92W on 15M, 76W on 10M.
First suspicion ... check the alignment of your bandpass filters.
73,
... Joe, W4TV
On 3/16/2024 11:56 AM, jerry wrote:
Hello,
I've been doing a bit of operation with my K2 lately. It really
is a joy on CW, and it fits perfectly under my big computer
monitors. But I have noticed.... On 40M, it does 101W out. But on
20, only 63W. This is measured with a Telepost LP-100A vector
wattmeter. The SWR is 1.4 to 1.
And it's not just gain decreasing with rising frequency, because it
does 92W on 15M, 76W on 10M.
Guess it's time to get out the schematics... But before that, I
should redo the test with a dummy load.
- Jerry, KF6VB
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