[Amps] RF choke switching

Vic K2VCO vic at rakefet.com
Thu Jun 9 17:43:39 PDT 2011


I'm planning another amplifier (2 x 4-400A, 1.8-28 mHz) and I was thinking that I would 
deal with the "RF choke problem" by having two chokes in series. The one nearest the 
plates will have enough inductance for 20-15-10 meters with no series resonances below 30 
mHz. The second will be 1 or 2 mh to provide enough inductance for the 1.8-7 mHz bands. I 
will use a vacuum relay to connect a bypass capacitor from the junction of the two chokes 
to ground on the high bands. Of course there will be further bypassing at the cold end of 
the big choke.

That way, both chokes will always be in the circuit to help keep RF out of the power 
supply but the resonances and distributed capacity of the large one won't upset the higher 
bands.

Is this a good idea or am I missing something?
-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/


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