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

[jim.thom jim.thom@telus.net]

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