Mine started doing it when I installed the ND6T/K5BCQ AGC board. It's not a ground issue, when I remove the board it stops. It looks to be correctly wired but I suppose I coulda fried something...it was my first real SMD assembly effort. It happens even with the board not connected to the RF path, i.e. just 5v and VOL-H connected. I suspect I screwed it up somehow. Maybe I'll assemble the second one I have and see if it works any differently.
Mark? ? ?AA7TA