SoapyTCPRemote

TCP based SoapySDR remoting, no clever protocols, just a TCP/IP byte stream.

Note: currently developed and tested on Debian stable only.. ports welcome (see below!)

Why?

Because I've tried SoapyRemote, and it always has streaming errors due to network underrun/audio overrun, which is daft when I have a solid 80Mbits/sec (10Mbytes/sec) from the source device to my laptop (measured using a simple scp command).

I've also tried USB/IP, which is a total loss for anything faster than keyboards.

I've tried a network audio solution TRX, which looks good with RTP for networking, but sadly due to having to switch between user and kernel mode for every UDP packet at 500Hz+ thrashes my wee source device to kernel panic & death =(

How?

By using the same approach as simple TCP/IP network protocols, use the capabilities of the underlying TCP/IP stack which is reliable, efficiently and implemented in the kernel so I don't have problems due to process/thread thrashing. Atop this, use stdio to manage buffering and data segmentation (less code for me to write), and finally, don't aim for stupid low latency, choose buffer sies that provide ~250msecs delay, this again reduces thrashing on the source device (which is tiny =)).

Building

You will need libsoapysdr-dev, cmake and build-essentials

Then it's the usual CMake incantations (on both source and target devices!):

• cmake -B build
• cmake --build build
• su or sudo -s
• cd build; make install

After which you should be able to check the driver is installed with SoapySDRUtil --info and run the server (on the device where your SDR is attached) SoapyTCPServer.

Usage

• Run the server on the target device: SoapyTCPServer
• Connect from the client: SoapySDRUtil --probe=driver=tcpremote,tcpremote:address=<serverIP>,tcpremote:driver=<serverSDR>
• Once you have a working conneciton string, use in your favourite SDR package such as gqrx.

Debugging

So it's not working first time? You can get significant details by setting the SoapySDR log level in the environment:

• SOAPY_SDR_LOG_LEVEL=<VALUE> where <VALUE> is one of: ERROR, WARNING, NOTICE, INFO (def), DEBUG, TRACE

Feedback

Feel free to raise issues for discussion or problems or features, better yet: submit PRs to fix my poor code please!