GM All:
Interesting that my FT-890 just off the repair bench has the capability
to offset the transmit carrier relative to the passband + or -
individually for USB and LSB. One does this by monitoring the signal in
the internal monitor or a second rx to adjust the tx audio. Since the
rig is a master reference osc/PLL the offsets are in memory. This is
instead of having a true audio equalizer on board. Actually works
pretty well except that it can't boost or cut at both ends of the
bandwidth. Does work well for fixing a "bassy" or trebley mic.
Same thing that Garey is saying tho. best adjustment is a compromise by
ear. to se the carrier point.
I have a great counter with TCXO reference and oven, but final set
points on ALL my alignments are done by ear.
FWIW
Curt
KU8L
Garey Barrell wrote:
One other thing as far as Carrier Oscillator crystals. With a little
care, you can almost always set the frequency 'better' by ear for best
audio, especially since the _CRYSTALS_ inside filters also change,
altering the overall shape of the passband slightly. Especially with
the Drake where even the BEST adjustment is a compromise.
I'd be willing to bet that very few radios would be at their optimum
'sound quality' by setting the CO crystal to a specific frequency, no
matter how many places came after the decimal point! :-)
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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