Mark,

I did exactly what you want the software for with the 'Dictation Buddy', many years ago (14-15?). I see it is still there with an updated version (mine was 2.2), possibly with a small fee. It is quite simple to use yet flexible enough. What you need in the settings is the "Sound activation", where you can also set the sound level to trigger the recording start and stop.

I connected my Yaesu VXA-100 headphone output to the PC's microphone input and it worked perfectly.

It was quite interesting to review the glider pilots' radio chatter from a specific day in a condensed form.

Tomasz
BravoMike