Evan, Yes, I understand the principle. I have look that with oscilloscope. I can test with a 2nd Mosfet But in fact the T/R signal coming from the arduino is more "short" as the "time of descent" of the TX power supply during the rollover. So in a little time your have the 2 supplies. The simplest test to prove that this comes from is simply disconnecting the TX from the relay. we’ll see if that unpleasant noise goes away then. Other solution increase the T/R time by soft.This may be possible. Otherwise, you did not tell me if you also had this noise when turning the encoder.It is also a 2nd problem a bit annoying.
