I did double check and I do have both A&B loop back checked. If I don’t select loop back B, then the blue trace increase slightly.I did not see anything that looked broken physically on the board. But determining bad parts can be more troublesome.
I’ll see if I can find anything looking at the control signals. Do you think these transmit paths will work down at 1.7GHz? I think I have an old SA that works to 1.8G
All the control signals seem to get to caps at the control devices. I’ll see if I can find the bits to do an external loop back or try to reduce the frequency so I can check it out with a spectrum analyzer. I’m guessing the transmitter for the B loop is not working and the signal I see is a leakage signal from the A loop.