On Mon, May 28, 2018 at 06:31 am, Raj vu2zap wrote:

current drawn is your power supply shutting down or current limiting?

Wow, that's exactly what it is!  When I try 80 M phone TX, the µB is on until I talk loudly into the mic, then the power supply light turns off.  It's supposed to be 12V, 2.08A, 25W.  I bought that power supply for the BITX40, but apparently it's not quite enough for the lower frequencies on the µB.  I am surprised.

Thanks for the suggestion!

I also found out that if you run a WSPR transmission with the antenna disconnected, the finals get very, very hot!  Don't do it!