I've a stock uBitx (3rd build I think) and have made a few contacts on 75 Mtr with a dipole in the trees.? Also using an antenna tuner to get a close to 1:1 match.? Often let it on for extended times receiving ft8 and listing all rec'd stations.? Went to operate it the other day setting up for a demo and it wouldn't transmit.? Receive was working but possibly weaker than I remembered.
Scoped the signal path back to Q90.? Q90 was not amplifying and ohm'd a short base to emitter.? Replaced Q90 and it now will transmit again.? I suspect any strong signal or static pulse on the antenna during receive will damage Q90.? Another ham 2 houses away and DX Engineering near by.? I'm considering a reverse connected diode across b-e of Q90 as an experiment to see if it eliminates failures.
By the way, into a dummy load it outputs 10 W on 80; 8 W on 40; 5 W on 20; and 1 W on 15 and 10 M.? My replacement Q90 may be limiting at higher freqs.? More scoping to do.
Doug
WA8UWV
