My fix for sticky controls
I have had rf on the ptt on 20. SWR was 1:1 My solution was to put a choke on the mic wires inside the box. Can imagine that using a small toroid on the key wires would help.
I use these .
I don't have hardly any shielded wire.
If you have rf on the circuit after you have put a choke on it you don't have enough choke.
I reviewed w1his articles. Had a lot of good ideas.
_Dave_ AD0B