[Amps] 10 kw CCS on 6M..using the 3CX-6000A7...Part 5

[Thomas Walsh]

And don't forget the L-Pi tank circuit, just adding a small L value from 
the plate to the blocking cap

and of course before C1 will cancel out any excess Tube or input C. It 
will be taken up by the tank.



On 9/27/22 16:11, jim.thom jim.thom at telus.net wrote:
> I was curious about extra shunt capacity to ground from the filament end if
> this fat assembly is placed close to chassis. The type 43 has some dielectric
> constant which increases the capacitance over air by that factor. The tube must
> have a Ck-g of around 40-60 pF (guessing). Of course input resistance is low so
> this extra C can be figured into the matching values.
> John
> K5PRO
>
> ## Stray C from fil choke assy lug to chassis is exactly 50 pf.
>
> Good thing you mentioned it. Grid to cathode C is exactly 42 pf.
>
> Target values for the Pi tuned input is  C1 = 127 pf,  .13 uh coil, then
>
> another 127 pf for C2.   127-92 =  35 pf.  A smaller C2 cap, with a
>
> min C of 10 pf was installed today.  IE: the tube C and 50 pf of
>
> the choke assy will be  absorbed into the C2 cap.  I figured out
>
> several methods of spacing the fil choke assy away from the chassis.
> To be done on future amps, but not this 6m amp. Easily done..and
>
> would reduce the stray C to an extremely low value.  The completed
>
> and tested tuned input video will be in the next 1-2 days.
>
> Also installed this am, was the input RJ1-A relay, bypass  RG-400
>
> coax, shrouded input SO-239, and bypass caps at cold end of choke
>
> assy, etc.
>
> Jim  VE7RF
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps