I have now set up Trunk Recorder for two different radio systems and on setting up the latest one I took notes and made a how-to guide. It is a Linux program that uses GNU Radio, Software Defined Radios and multiple recorders to record audio from different frequencies at the same time, putting each conversation in its own audio file. The guide uses a Ubuntu Minimal CD and includes modifications to GNU Radio and Trunk Recorder to simplify things by removing support for expensive SDRs if you only want to use cheap RTL SDRs.
https://github.com/robotastic/trunk-recorder/wiki/MinimalInstall
https://github.com/robotastic/trunk-recorder/wiki/MinimalInstall
