[Amps] SB-220 parasitic suppressors

Steve Thompson g8gsq at ic24.net
Thu Nov 4 10:10:48 EST 2004


On Thursday 04 November 2004 14:29, R. Measures wrote:
> On Nov 4, 2004, at 12:15 AM, Steve Thompson wrote:
> > Tony King wrote:
> >> At 01:21 AM 11/4/2004, R.Measures wrote:
> >>> <snip>
> >>> A GS-35b has 0.12pF of anode-cathode feedback C.  An 8877 has 0.10pF
> >>> of it, so they have a fairly similar amount of internal feedback.
> >>> Our 8877 low VHF-Q parasitic suppressor retrofit kit has both an
> >>> anode suppressor and a cathode suppressor.  It comes with a money
> >>> back guarantee.  So far, the only refund has been to a guy who said
> >>> he did not know how to solder. --  Today's trivia question:  At its
> >>> max freq of 1000MHz, what is the reactance in ohms of the
> >>> output/input feedback path in a (g-g) GS-35b?
> >>
> >> Very interesting.  My guess: 1326
> >
> > Feedback C on the data sheet is almost certainly measured at low
> > frequency.
> > The feedback characteristics at V/UHF might be different.
>
> Not for any reason I can see.  The dielectric is a vacuum, not an
> organic compound.
The dielectric won't alter, but the impedances probably will.

Steve


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