[Elecraft] When Transmitting on FT8 - KPA500 has issues - KD8ZYD

[Andy Durbin]

"That leads me to believe that the K3 output is rapidly changing on and off"

I have not looked at the video but this sounds very similar to a problem I have seen.   In my case HDSDR sound output had spontaneously changed to TS-590 TX CODEC creating a feedback loop through the PC.  Break the loop and all is normal.

73,
Andy, k3wyc