[ARC5] Parasitic suppressors on ARC-5 VFO?

[David Stinson]

Ian Wilson wrote:

> Having a tough time getting a 7MHz VFO to be stable. The effect is a
> random 'warble' of a few 100Hz, with occasional 'pops' of a few 100Hz.
> The VFO is fed from a stabilized supply.
> 
> I believe the problem to be a parasitic VHF oscillation (see later for
> stuff that I've already tried). If I insert a 1k grid stopper resistor
> the problem goes away (but chirp and drift are made much worse). Is
> there arcane wisdom on parasitic stoppers for plate & grid of the 1626
> for this type of problem?

I have noted a similar problem that "went away" when my latest
7 MC rig warmed-up for over an hour, but I haven't yet
investigated it thoroughly.  Your work will help save time.
Were I were you are, I would try inserting some ferrite beads
in approriate locations at the tube socket.  If that stops the
problem, it confirms your suspicion.
73 Dave S.