The problem is that just about any trimmer cap you choose is going to be less 'stable' LONG TERM
than the crystal. So the good news is that you can adjust the frequency, the bad news is that
you're going to have to! No trimmer is going to be as stable as a good crystal, and since most
electronic stuff doesn't LAST for 50 years, you're better off without a trimmer.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Jim Shorney wrote:
On Sat, 17 Sep 2011 10:10:53 -0400, Eddy Swynar wrote:
What can REALLY be vexing, though, is when the crystal(s) used in carrier-generating
oscillator frequencies "migrate": I once had an SB-102 transceiver that sounded
very tinny& nasal-sounding on LSB only---much to my chagrin, THAT carrier generating
crystal had shifted just enough so as to put a goodly portion of my signal REMOVED from the
passband of the IF filter!
I always wondered why some manufacturers didn't put adjustment trimmers in the
carrier oscillator curcuit. This is one of the most critical adjustments in a
SSB radio, and I'm a-r enough about it these days that I check my frequency
counter agianst a rubidium standard before I make adjustments. I actually added
trimmer caps to the HW-101 that I had years ago so I could get it right.
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