[AMPS] parasitic suppressors

[Steve Thompson]

In message <iuzLQJA55fC3EwjV@ifwtech.demon.co.uk>, Ian White, G3SEK
<G3SEK@ifwtech.demon.co.uk> writes

snip

>The suppressor is wired in series with the tube, but the way it works is
>that its resistive part creates a permanent PARALLEL load impedance for
>the tube at VHF, low enough to make its gain drop below the oscillation
>threshold. If you analyse the circuit in detail, you find that the
>series-to-parallel impedance transformation depends on the stray
>inductance that is causing the VHF resonance. There's the problem: the
>load impedance seen by the tube depends partly on the suppressor
>characteristics BUT ALSO on the stray inductance in the amplifier.

And the suppressor does stuff all at the vhf frequencies where the tune-
C/coil combination looks high impedance.

snip

Steve

--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm