Allard, I've noticed that after I tune around a bit the frequency will occasionally change by 1 increment. I think there are stresses in the wiper mechanism of the potentiometer and that makes it move. Doesn't happen all the time. I've also noticed that if I move the front panel of my Lexan "enclosure", it can torque the VFO pot and cause it to move an increment up or down. Would that small change cause the dial to lock while transmitting? Could explain what EA3IAV is seeing...Perhaps having the lockout sensor trigger on something greater than "any change"?
Mark
W4MAP
