Hi guys, working on my sx-117 and encountered a strange problem and want to
pass it by the crowd.
I was having trouble receiving signals until I realized the BFO control was
turned all the way to the right. Rotating the control all the way to the
left, brought the receiver back to life. AM works great but SSB has a
problem. The sound of SSB sounded similar to an IF shift control being
turned to far to one side (tinny). Reading the alignment procedure for the
BFO, I followed it exactly. It states, put the receiver in USB, put on the
100kc calibrator and tune to almost zero beat. Switch to LSB and the beat
note should not change appreciably. Well, when I switched sidebands, the
zero beat was out of there.
Going further in the book, I followed the "Major" BFO adjustment procedure
and the receiver came back beautifully. Nice signals good reception, AM and
SSB but, here is the perplexing problem.
I can set the rig to LSB, and tune in a LSB signal. Switching to USB,
results in the signal moving 1khz in one direction or the other (crystals).
This is normal. However, I can retune the same LSB signal and understand
the signal as though the receiver was still in LSB even though the receiver
is in USB mode!
Basically, it does not seem to matter if the receiver is in LSB or USB, I
can still make any SSB signal regardless of their sideband, intelligible. I
believe it is a BFO thing. I think it is out of adjustment and inserting
carrier when it should not. Sort of like an older receiver without a
product detector. With a BFO, it did not matter what sideband the
transmitting station was on, you could always tune it in.
Any ideas out there would be greatly appreciated.
Bill
K2WH
Bill (Group Owner)