Vic,
I've been following your trials and tribulations on the Henry amp.
I was considering getting one to add to my mobile HF amp collection.
FWIW the big Skywalker (Lee Martin) amp kits run this device lineup.
I am able to hold a solid 14V on my 2879's and easily bang the end of
the peak reading Bird 1Kw slug hard over with a two tone into the amp.
In fact output is nearer 1200 peak.
Could the amount of negative feedback be limiting your full potential?
Phil G4ZOW
>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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>
--
phil
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