I'm still trying to figure out why signals drop when I switch in OPT1
on my newly-built SSB board for my K2/100. The static goes way down,
but do do the voices!
Last weekend I discovered rfc2 shorting out to they can of crystal
X7. When I rewound it that helped some.
Today I rewound T2 and that didn't make any difference at all.
I've been around once with Gary, and I think all the obvious things
are right. The crystal cans aren't shorted to ground, the caps are
the right values and aren't shorted by DC either, the diodes are in
the right way and the voltage checks on the switching network are
fine.
Gary says there should be a "small but progressive" signal loss
through the SSB filter. To check this, I tuned to the birdie at the
bottom of 40 meters, and dragged out the scope.
I set in on a 2mv scale with a 1ms sweep (slow) and used the
measuring cursors to take an average amplitude. I did AC coupling
with a 1X probe (so may have been loading things down some). Then I
shoved a 3 inch leftover component lead into the probe clip so I
could poke around in the small places.
Here are the numbers, from input to output:
P2 -> T1(2) -> T2(4) -> X1 == ~ 1.75mv
before X2 1.28mv
before X3 1.28mv
before X4 1.28mv
before X5 1.28mv
before X6 1.20mv
before X7 1.20mv
T2(3) 1.20mv
T2(1) --> all the way out to P3 ~1.68mv
I can go around again with Gary -- but before the weekend goes and
before I tear too much working stuff up, thought I'd throw it out to
you guys to see if there is anything obviously wrong with these
numbers or the way I acquired them.
Thanks,
-- Ward
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