[ARC5] Unstable VFO

[David Stinson]

Ian Wilson wrote:

> Posted a while back about a haunted ARC-5 VFO on 40m. Strange 'warbling'
> instability that I just couldn't defeat despite changing many parts.
> 
> Someone - Ken Gordon, I think - suggested a bad joint around the tube
> socket. The answer turned out to be a bad joint somewhere in the grid
> circuit.
> 
> The VFO is quite stable now, running from a 182V stabilized (Zeners,
> sorry) supply. The original dogbone ceramic capacitor has been replaced
> with a polystyrene equivalent that appears to be doing a fine job.
> 
> This has taken way too much time, need to get the rig back on the air
> now.

Good news.  I think I'll take that suggestion on a BC-459
with a similar problem.

Since we're talking about this, it reminded me of the suggestion
to use ferrite beads to kill VHF parasitics, if that were the problem.
I have a similar situation that is certainly rooted in VHF parasitics.
What is the proper procedure for selecting the "right" ferrite
for a problem?
D.S.