Hi Hans,
I see my QMX as a very well thought out rig. Works nice. FT8 and CW. I built it for +12V.
But the "too" small PCB means there is no place for an additional dedicated GPS connector for instance. And also no place for some improvements on BPFs and LPFs if needed. OK, this is perhaps marginal.?But about the two SMPSs, I think you could live with just one.
If you would supply the MC?permanently with the 3V3 LDO and than switch its input from +12V at powerup to a stable +5V SMPS it would be beneficial. Than you would have to deal with just one SMPS's interference. On a cost of a bit larger supply current. A win-win. Just my thoughts.
73 Bojan S53DZ
PS: Why do I have a feeling that the QMX Volume control encoder would be better to work counter-wise and not the opposite?
The frequency is increasing in that direction and the volume is decreasing.
