I guess it’s worth point out here that while this would work, if tracking of said balloon launch comes down to just your station receiving, all it would take is a badly timed observation for tracking to be lost.
Having launched a heap of high-altitude balloons, the last thing I would want is for a critical tracking station to go offline at some critical point in the flight, like landing… Better that the tracking station is dedicated to the job, which is possible with a RF splitter and another RTLSDR.
It’s not the same thing as is discussed by the OP. My intent was to listen in to passes of the ISS APRS digipeater and relay those into APRS-IS. It would only function when an observation is in progress.
As you mentioned, scripting is the easiest way to get it up and running.
Using pre-obs-script and post-obs-script you can fire up any software using the sdr, and then stopping before the next obs. This is exactly how I handle gr_satellites, just inverted for this.
Check out the stopping code of my implementation and you’ll see how it can be done.
Here’s how to make satnogs-client execute the scripts.
Make sure to read and understand the way this works before implementing it.