[Elecraft] KPA100 TR Switch isolation problem

I modeled the switch and have identified the source of the problem. There is a resonance formed between the junction capacity of D12, D14 and the 100uH inductor RFC3. When you add the 12pF cap or a scope probe, all you do is move it around a little. The easiest way to kill this problem

Re: [Elecraft] KPA100 TR Switch isolation problem

Bob, Bingo! You nailed it I'm sure. Your explanation accounts for other things I saw when originally troubleshooting this circuit. I arrived at the 12 pF 'fix' by accident when noticing that a scope probe made the problem go away but I knew it was only a patch .. and did not address the