The waterfall looks like your audio sampling rate goes wild or fussy.
Lance -- WSJT-X works with 48kHz 16-bit. Check the audio interface you're using to make sure that is what is set. Something might have changed it.
Thanks Jim, my bad. It is interesting that the change is in the middle of 15 s period. The time compression indicates that there are also missing audio frames. Is it possible that USB link is intermittent, bad? On the other hand the fail mode looks stable. 73, Reino oh3mA
