Help Requested: Record only portions of spectrum as IQ with RSP1A

[Dennis McGough]

Goal: Set up a system that records all amateur HF allocations (1.8-30 MHz).. but only the amateur allocations (with a little overlap on the edges). Preferably in a headless fashion (command line only) using something like a Raspberry Pi. Eventually, I'd like to run this from the command line as the recording process only, outputting the data to an NFS share. No processing on these headends, only output to recording (and maybe network for remote decoding if I want to get really fancy.

The problem I've found so far is that I can find ways to record a single chunk of spectrum to I/Q with a few different pieces of software, but it looks like only one receiver process can receive data from the receiver at one time via USB. SDRUno has a concept called VRX, but before I got too far into one particular solution, I wanted to see if any members of the community had any suggestions. 

One piece of receiver hardware (preferably RSP1A), some (but not all) of the received spectrum, saved to I/Q format. That's the goal. Any suggestions or direction would be appreciated.

[Dennis M]

This is the VRX concept in SDRUno I was talking about: https://www.youtube.com/watch?v=aPLcu3Nwes0 - but I don't know if I can record I/Q from within a VRX process, and I don't know if there are better ways to do this. 

[Adrian Musceac]

That's because you can't share an USB context directly between processes, you need a proxy. Libusb thing. Just have a single process talking USB and spread the data around via sockets. You'll be limited by USB bandwidth.

[Dennis M]

Do you know if GQRX natively supports this sort of proxy setup? If I go the SDRUno route, I'll be taking a primarily GUI-driven app and working backwards to command-line if I can. I'm trying to establish what all my options are, so any advice or direction would be appreciated.