Hello,
I friend borrowed me an Omni VI, which is producing very disturbing
audio-clicks in fast QSK mode, at any CW speeds, even with very slow keying.
The clicks are louder than the received signal and quite distracting.
I am including symptoms below for those who want to read on. Any ideas, and
suggestions highly welcome.
73
Gerd DF9TS.
===
The TRX is click-free when connected to a dummy load. Symptoms appear with
antenna signal (or white noise) on the receiver input.
The clicks are produced in fast QSK only on key release ("key up") only.
"Key down" is not producing clicks.
TX signal is ok and click-less and without chirp (as verified with 2nd
receiver). RX audio signal is with these clicks.
I verified the "TD". "T" and "R" signals generated for internal tx/rx
switching with a scope. They look similar to a quick Spice simulation I did
of the circuit. I did however not see a lag between "T" going down and "R"
going up.
Slow QSK is without such clicks.
On "slow QSK" the RX audio comes back up slowly on "key up".
On "fast QSK" the RX audio comes back immediately on "key up".
This makes me wonder if the cause is a timing issue on "key up".
I did align the TRX following the manual, twice. BFO is well aligned also.
The rig behaves as expected. Sensitivity and filters ok.
Removing connector 52, extensively discussed in this list, makes no
difference for this OMNI VI´s clicking.
The clicks are present on Loudspeaker as well as on "Audio Out" cinch
socket.
Tnx for reading this far ;-)
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