LibreSDR Compatibility with UHD and GNU Radio

[Pavel]

Short answer: Treat LibreSDR as a board with its own supported UHD fork or release, firmware and FPGA image. Similar device APIs can enable GNU Radio use, but they do not guarantee that every Ettus image, utility feature or update is interchangeable.

Before you start​

• Use UHD discovery and probe utilities before GNU Radio, OpenAirInterface or srsRAN. Save the exact UHD version, FPGA image and device arguments.
• Match the host interface to the requested stream: USB-controller limits matter for B-series radios, while N- and X-series radios require a planned Ethernet path.

Step-by-step method​

1. Step 1: Identify the exact LibreSDR model, FPGA and RF transceiver. Record the vendor-recommended UHD version, repository or package and matching device images.
2. Step 2: Test discovery and probe with that supported stack before installing several UHD versions. Save the full output, device arguments and reported firmware/FPGA revisions.
3. Step 3: In GNU Radio, use the UHD source or sink with the proven device argument, one channel and a low sample rate. Confirm tuning, gain and streaming before adding multi-channel processing.
4. Step 4: Create a separate environment before testing a newer upstream UHD release. Keep the known-good host package and board images available for rollback.

Concrete example​

A board may be command-compatible enough for uhd_find_devices but still require a vendor FPGA image and device tree. Discovery alone is not evidence that a standard B210 image can be flashed safely.

How to judge the result​

Compatibility is demonstrated when the documented stack discovers, probes and streams the intended channels at the required rate, and the same configuration survives a restart.

What to record​

• Monitor overflow or underflow indicators during a sustained test, not only during application startup.
• Clock and PPS solve different problems: 10 MHz supplies a frequency reference, while PPS supplies a time-alignment event.
• For coherent work, verify phase behavior and timestamp alignment with a known shared signal rather than only checking that two channels display data.

Common mistakes​

• Changing several hardware, software or RF variables at once, which removes the controlled comparison needed to identify the cause.
• Treating one autoscaled screenshot or one unusually good result as proof without recording the settings and repeating the test.
• Forcing an Ettus firmware or FPGA image onto third-party hardware because the transceiver is similar can make the board unusable.

Final check​

Reboot the host and power-cycle the radio, then repeat discovery, probe and the sustained stream. Keep the exact UHD, firmware and FPGA versions with the working result.