[Central-Electronics] 100V RF phase/Null adjustment touchy

[k6jek]

I've been fooling with the 100V.  The carrier suppression was lousy.  The usual parts are relatively new and closely matched so I figured what the heck, try the RF phase adjustments.

Using a FLex radio as a spectrum analyzer, with the mod caps out to keep audio from confusing the issue, I adjust those two RF transformers, tweak this one, adjust null pots, tweak that one, adjust null pots.  I was able to make a huge improvement, from a miserable -20 dB to -60 dB.  Pretty good, huh?

Except the way this thing is adjusted, the null pot adjustments on the front are super touchy.  The slightest nudge of the knob and I mean miniscule nudge and I lose 10 dB of carrier suppression.

What have I done wrong, and what should I do to fix it?

Jon