Dear Digirig Experts,
I’m having an issue with my Kenwood TS-480SAT, Digirig, MacBook Pro, and WSJT-X. I’m not sure who the culprit is but it’s somewhere in the audio path, and I’m pretty sure it’s not the radio because I ran PSK-31 with this radio for years without seeing anything like this. First issue was the audio level: the audio level from the radio was set about midway but WSJT-X said it was way too high. I turned the radio’s level down as low as it would go, but then I was seeing a bunch of artifacts in the waterfall chart. I discovered that the Digirig has a 20db attenuator that can be activated by cutting a trace, so I did that. That allowed me to run the radio at a more reasonable level and get the low-level A/D noise out.
The bigger problem is that my waterfall in WSJT-X starts turning to mush the longer I run it. Screenshot attached. If I quit WSJT-X it goes back to clean signals. Also if I select a different audio device (say built-in speaker and mic) and then re-select the digirig, the signals go back to normal. The act of re-opening the device appears to be the key, and over the course of 10-15 minutes the signals get noisy again. I haven’t seen this on any other type of audio device.
In the screenshot you see:
- 10:46:15 to 10:47:00: absolute mess of a signal.
- 10:47:00 to 10:47:30: I switch the audio device to built-in mic/speaker and then back to Digirig.
- 10:47:30 to top: back to normal signals.
Note this was before I put in the 20db pad, so there’s a bunch of vertical lines that are just noise. Those mostly went away after cutting the ATT trace on the Digirig.
Has anybody seen anything like this before? Between the levels being terribly out of whack and this noise issue, It seems like there’s something very wrong in the A/D conversion.
