Hi Don,
I would put getting the RF out of your power supply high on the priority list. First rule of troubleshooting is to fix what you know is wrong.
yes, I completely agree with you!
Now I will replace my old PSU with one that does not change the set parameters on it's own and look into either building a new antenna or an antenna tuner to be able to send without fear.
The PSU is the first thing I wanted to replace.
However, I have some trouble finding a lab PSU that gives me significant more confidence than the one I already own and does not cost way over 300 EUR.
So I guess I build a small PSU with a fixed output voltage specific for the QDX, which I need for portable use anyway.
Maybe a 78S10 / 78S09, some caps and a choke will do the tick.
Now that I think about it, filtering RF on the power cable with ferrite cores should have been my first step ... :facepalm:
73 Alexander DM8TE
Alexander