[Amps] RF choke switching

[Larry Benko]

  Vic,

Look at my post of a few hours ago.  Two non-resonant chokes in series 
can together be resonant.  This is basic circuit theory and there is no 
way around the issue.

Larry, W0QE

On 6/10/2011 8:43 AM, Vic K2VCO wrote:
> Because if I do this, the bigger choke will be out of the circuit completely on the high
> bands. My method will leave it there, after the bypass, to provide additional filtering on
> the HV lead to the power supply.
>
> On 6/9/2011 11:12 PM, Angel Vilaseca wrote:
>> Vic,
>>
>> Why not use the vacuum relay to short the big choke? That is what is done on the tank
>> circuit when bandswitchig.
>>
>> 73 de HB9SLV
>>
>> Vic K2VCO a écrit :
>>> 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?