Carl wrote
> The 6M amps I build use a regular Pi-Network, same as an HF amp.
> The only difference is that more of the Tune C is in the tube
> than at 10M. Since the parasitic frequencies of the 572B is
> close to 6M it becomes harder to suppress without excessive
> loss in the suppressor.
Good morning Carl,
The best looking homebrew 6m linear I have seen was made by
Jim WA7JCO in Phoenix AZ. He showed me >1.5kw keydown on 6m
with an 8877. There was no parallel plate capacitor - instead
he used a vacuum variable as a tunable series capacitor.
This replaced the blocking capacitor, and by placing a
capacitor in series with the <large> anode capaciance
it enabled an efficient tank Q to be achieved.
I believe he told me that no suppressor circuit was required
in this case.
Hope my rough drawing helps.
Tune L
Cap
--------||-|--^^^^^^^^^-|--------- output
| | |
| ( |
--- ( --- Load Cap
Anode ( ---
8877 RFC ( |
( |
| Gnd
|-----|
| ---
| --- bypass
| |
HV Gnd
Regards
Martin ZL1ANJ
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