I've been playing around with GNU Radio, and published a GRC file that might be useful to amateur radio operators. It's a 2-channel narrowband FM receiver This lets you monitor 2 frequencies in your stereo audio output. Useful for monitoring 2m calling, and also your favourite repeater.

I want to expand it to even more channels, but I was having trouble with performance. Not sure if it was the SDR, my PC, or how I built the pipeline. More experimentation is needed.

I'd also like to try adding a TCP listener, so that GPredict can drive it to listen to satellite passes.