Just a question to the experienced SDR freaks..
Is it worth trying this under Windows or would you rather try it under Linux?
I have only experience with gqrx under Linux and it works fine (no crashes).
There is a dedicated site http://gqrx.dk/
I currently use an SDRplay RSP1a for Es'hail-2 reception but the program also supports the RTL-SDR sticks.
Of course there are also other SDR programs for Linux, e.g. CubicSDR.
We'll have to find what is the easiest way of incorporating some form of locking.
gqrx has a nice remote-control interface but it has only a single receiver.
CubicSDR can run multiple receivers in the passband (so you can listen to more than one transmission at the same time) which could be nice as a starting point for locking to the beacon.
However, at the moment I can not run it on my system due to a bug in combination with the native Nvidia OpenGL driver. First have to find how to work around that.
DB8TF is right in that most of the programs appear to be "optimized for ease of programming" rather than for "least CPU usage". However on a machine that isn't 10 years behind current state-of-the-art you still can use it.
(e.g. I have a Core2 Duo CPU E6850 @ 3.00GHz)