Thanks Tim, Digger and David. Your support is much appreciated especially from Kit-Projects.
Digger,I am using a miniature MIL Spec rotary switch for the Kit-Projects AGC board. No problems there.
Playing with the settings using the memory manager I have got an acceptable response now.
However, I am going to try the last KD8CEC Nextion firmware to see if that makes a difference. Strange this temporary freeze only happens when the tuning step is changed. I wonder if a second Nano will speed things up?
I used Murata T filters on the power leads and this has killed the motor noise but some mild "motor boating and ticks" can still be heard from the encoder on some frequencies. Have you put added caps on 7805 input side? Has this made any difference. Or perhaps a separate buck converter from the 12v input. Does that make a difference or not?
Sorting out a new "screened" wire loom for the AGC board and A7 connection now before researching how to set up a second Nano. I am not sure what firmware goes on the second board?
Best wishes Derek G4VWI.