Hey OM:

Well the dual gate FET's RCA was using were sub 1Ghz range so not only
were they controlling the bias, also they controled the miller effect
with an isolated supply for the second gate.

I should has ment 50Mhz to 900Mhz it was the splitters we used were
rated 5Mhz to 900Mhz.

So 8 varicaps in back to back series would be to much? Giving you
double the voltage and the same C.
You may be right 54Vdc would be way too much to have floating around
to tune them.
I remember the ones RCA used were so small if you dropped one on the
floor you would never ever find it.

They diode switched in 2 sets of coils in both the OSC and TRF, to get
LO VHF, HI VHF, and UHF.
So like they had 3 coils in series, all 3 for the LO, 2 for the HI,
and 1 for the UHF

73 OM
de n8zu


On Nov 29, 11:32*pm, brian whatcott wrote:
lw1ecp wrote:

/snip/

- "Series varicaps"?. Sorry... they are back-to-back in series
already!.

I understood the suggestion was to place two varicaps in series
NOT back to back in order to extend the voltage range.
But that implies two series strings, in order to maintain the
capacitance range over a longer voltage swing??

Brian W