I'm still trying to figure out why I can only get about 600 watts output on 14
MHz from my Henry SS750 amplifier (8 x 2SC2879).
I measured the output into the dummy load with various levels of drive, from 10
to 100w in 10 w steps. I found the following relationship:
In Out
--- ---
10 113
20 216
30 305
40 384
50 427
60 482
70 520
80 540
90 570
100 601
....
150 687
Obviously, the gain drops as the power increases. Is this normal?
I did some research, and the 2SC2879 is rated at 13 db gain (minimum) at 28 MHz.
with only 12.5v on the collector. The attenuator that's in the Henry circuit on
14-28 MHz is only 2 db. That should leave 11 db gain. Allowing for 2 db of
loss in the splitter, combiner, and filter, that leaves 9 db, which should
produce 800 watts with 100 watts drive. One would expect even more gain with
13.8v.
Something isn't right...I think. I am not a solid-state guy -- help!
73,
Vic, K2VCO
Fresno CA
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