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Audio latency and CW QSK

Posted: Thu May 04, 2017 3:59 pm
by W2DLC
OK, I've narrowed the CW transmitter overload problem to the latency of the receiver. Basically the QSK T/R switch does it's job before the signal gets through the SDRPlay, so the SDRPlay doesn't get muted before the next key down. I don't have any hang time control over the QSK switch. I installed the ASIO drivers hoping to solve the problem, but it didn't help. Any suggestions?

Re: Audio latency and CW QSK

Posted: Fri May 05, 2017 8:37 am
by DK7OB
Unfortunately if have no suggestion, but I am suffering from the same problem.

How long is your delay/latency? I measured about 130ms from antenna input to audio output on a good day (it depends a bit how the audio output buffer size is adjusted) and that pretty much destroys any QSK. I am running Linux with gqrx, but also tested Cubicsdr where the latency was even bigger. I would be interested to know if there is a major difference with Windows/SDRuno.

Re: Audio latency and CW QSK

Posted: Fri May 05, 2017 12:52 pm
by W2DLC
Well, changing the quality setting to high helped a lot, and I set my QSK switch to half break in. In that setting, it continues to mute the receiver inputs for about a second after the last key down.
I made a contact with it that way last night and it worked OK.
BTW, I installed the ASIO drivers, but they don't seem to be fully implemented in SDRUno yet, and they aren't available in SDR Console 2 at all.