locked Compensating for audio lag from SDR? #AudioIssues


Bruce KX4AZ
 

One of my SDRs outputs audio with about 1.5 second lag time.  WSJT-x seems to decode FT8 OK, but any station sending with a "real" lag time might be missed.  And I don't like sending inaccurate time values to pskreporter.  Other than manually readjusting the PC clock to compensate for the delay (which would mess up time stamps generated by other apps), is there a setting in WSJT-x which can be adjusted?


Bill Somerville
 

On 08/09/2021 11:06, Bruce KX4AZ wrote:
One of my SDRs outputs audio with about 1.5 second lag time.  WSJT-x seems to decode FT8 OK, but any station sending with a "real" lag time might be missed.  And I don't like sending inaccurate time values to pskreporter.  Other than manually readjusting the PC clock to compensate for the delay (which would mess up time stamps generated by other apps), is there a setting in WSJT-x which can be adjusted?
Hi Bruce,

1.5 S audio latency is very high! Compensating is not really practical, and for a station that also transmits probably impractical. Adjusting the local machine time will definitely cause Tx signals to have an equivalent delay, so that doesn't work.

Time offsets are not posted to PSK Reporter.

73
Bill
G4WJS.


Alan G4ZFQ
 

1.5 S audio latency is very high!
Bill,

I can beat that!
I have a local Kiwi which interfaces with a web browser. When I feed audio from that the DT is about 4. WSJT-X still decodes more WSPR spots on busy bands than the native Kiwi multi-band software.

Some sort of RX adjustment would be useful but I'm sure only to a tiny proportion of WSJT-X users. And that number will probably decrease as SDRs evolve.

73 Alan G4ZFQ


Bill Somerville
 

On 08/09/2021 12:01, Alan G4ZFQ wrote:
1.5 S audio latency is very high!

Bill,

I can beat that!
I have a local Kiwi which interfaces with a web browser. When I feed audio from that the DT  is about 4. WSJT-X still decodes more WSPR spots on busy bands than the native Kiwi multi-band software.

Some sort of RX adjustment would be useful but I'm sure only to a tiny proportion of WSJT-X users. And that number will probably decrease as SDRs evolve.

73 Alan G4ZFQ

Hi Alan,

IIRC WSPR has about -6 second tolerance, although I'm not certain that the last symbol or two gets passed to the decoder in such an extreme case.

73
Bill
G4WJS.