Because I use a dedicated computer for my radio gear, it is very rare for me to ever have issues. Once something works, it tends to stay working. Imagine my surprise yesterday, when I decided to check out FT8 and found it was no longer transmitting.
A quick check of the program setup didn’t reveal anything obvious, so I checked a couple of other digital mode programs (WinWarbler from DXLabs and WinLink on HF). All had similar issue (working a couple of weeks ago, but no longer transmitting).
That pretty much left two possibilities, a windows update messing with the mixer settings, and the K4D itself. I pulled up the windows mixer tool and it was clear that wasn’t the issue – I could see the modulation on the level meter.
I’ve had a K4D for a few years now, and it has been pretty much flawless, but that was my last culprit. Apparently one of the recent software updates (adding remote capabilities) wound up resetting the audio source and levels for digital modes.
Pressing the TX button, then LINE IN button, showed that the SOUND CARD level was set to zero. Using WSJT-X’s TUNE button to generate some tones and put the rig into transmit, I adjusted the SOUND CARD level until the ALC level was at 5 (last segment flickering). That required a level of 41 as you can see above. I checked WinWarbler, and it was generating the correct ALC action for PSK31 as well.
