Ernie....
You say you had the carrier completely eliminated, and it re-appeared. How
are you measuring? Do you use a scope, a wattmeter or a report from
another ham?
I've found it easier to listen on another receiver while adjusting the
balanced mod trimpots. Even if you also use a scope you can hear the
"bottom fall out" of the carrier. Be sure you have the microphone gain all
the way off when doing this. Also, the two trimpots interact, so it is
necessary to go back and forth repeatedly when adjusting them.
With the CA3053 balanced modulator and a ladder filter, you won't ever make
the carrier "completely disappear" on both sidebands...much less at the same
time. But you can reach optimum by switching back and forth between USB and
LSB while making the adjustments, so you get to a happy medium.
Again, this is facilitated by listening slightly off frequency with another
receiver.
73
Phil C. Sr.
k4dpk
----- Original Message -----
From: "Ernie Popp" <k2ep@nycap.rr.com>
To: <tentec@contesting.com>
Sent: Wednesday, December 03, 2008 8:40 PM
Subject: [TenTec] Problem with carrier on LSB on my Omni 6+
Omni 6+
During CQWW ssb contest, I noticed that I had carrier present on LSB while
operating on 40M. I checked and found it was present on all bands only on
lower side band. Upper seems fine. It seems more severe on 40m. I first
checked the 9mhz bfo crystal. It was close and I fine tuned it a little.
This had no real effect and still had carrier on LSB. Next I adjusted the
balanced mod. I'm not sure if their is a special procedure for this. I
was able to completely eliminate the carrier. After several day, the
problem reappeared. Once again, I adjusted the balanced mod to correct
the problem. Checking tonight it's back. I'm assuming that something is
unstable in the balanced mod circuit. Why is USB not affected? Has
anyone experienced this? Any Ideas?
Tnx, Ernie K2EP
k2ep@arrl.net
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