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

[Jim Candela]

----- Original Message ----
From: K6JEK <k6jek at comcast.net>
To: Jim Candela <jcandela at prodigy.net>
Cc: "<central-electronics at mailman.qth.net>" <central-electronics at mailman.qth.net>
Sent: Wed, March 24, 2010 9:42:26 PM
Subject: Re: [Central-Electronics] 100V RF phase/Null adjustment touchy

That idea with the pots is a good one. I may do that. These are way too touchy.

What do you mean the 9 MHz coils were spaced too far apart?


Reply by Jim, WD5JKO:

   On this 20a, there was an additional hole where the two  9 Mhz RF phase shifter coils were located, and whoever built that rig (some were kits) used the wrong hole to mount one of the coils. I could get a good carrier null, but as the audio level went up, I lost the sideband suppression. The problem drove me nuts. Along the way I removed the two 10 turn wire wound carrier null pots, and replaced with carbon 1 turn pots. The problem remained. After repositioning the one miss-placed coil, and re-aligning, the issue was gone.    

Jim
WD5JKO