[Amps] RF choke switching

[Eddy Swynar]

Hi Vic,

For some time now I've mulling over a very similar set-up here...only in my instance, I was thinking of somehow shorting the bigger inductor whenever I wanted to use the higher frequency bands, and letting the two chokes stay in series for operation on 160-meters...

I was hoping to use a 200-uh. solenoid choke for the high frequencies, and a multi-pi National choke (3.0 mh.?) for Topband.

I wasn't planning on using anything more fancy here for a switching medium than a manually-inserted (by way of a wooden dowel) shorting banana plug. That, or a mercury switch that might be somehow made to tilt "on command". I s'pose it'd be a requirement, too, to somehow mount the coils at right angles to one another...?

Interesting stuff, indeed...

I sure would be appreciative if you might keep us all informed as to your progress in this regard, Vic, with my sincerest of thanks in advance...

~73~ de Eddy VE3CUI - VE3XZ


**********************************************************************************************************************


On 2011-06-09, at 8:43 PM, Vic K2VCO wrote:

> 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/
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps