LibreSDR Revisited
Simon Brown • February 23, 2025
16 MHz Bandwidth!
Default Firmware
Here you see a screenshot from SDR Television (work in progress) running the LibreSDR at 16MHz bandwidth.
This is the standard firmware from Evariste, F5OEO who has done a great job.
Compare 16MHz with LibreSDR to 5MHz with the PlutoSDR, a big difference!
Many thanks to Mike, G0MJW for the screenshot.
Overclocking
Other firmware is available which overclocks the LibreSDR, but I've not looked at this. Here are the key points:
This is an unofficial port of PlutoSDR onto LibreSDR a.k.a. ZynqSDR. The repo is based on day0wl's repo with several enhancements:
- Optimized linux kernel and buildroot to support higher practical sampling rates with libiio/PlutoSDR API (20 MSPS without overlock, compared to ~10 MSPS stock)
- Xilinx Zynq SoC overclock support (27.5 MSPS achieved with overclock to 1100 MHz CPU + 750 MHz DDR)
- Use LVDS mode for AD9361 to support max sampling rates in 2T2R mode
- Based on PlutoSDR v0.38 firmware (Nov 17, 2023)
- Prebuilt firmware with different overclocking options
Support
To support bandwidths higher than 6MHz a new release of SDR Console is required, so keep an eye out for announcements.
SDR Television v1.0.1 October 29th, 2025: Fixed a fatal bug in the receive AGC if the output soundcard sample rate is 96kHz or 192kHz. Downloads are at the bottom of this page.
Previous: Version 1.5.2 This release fixes a bug, improves the user interface and adds a new calendar. Download link is at the bottom of this page.
And the award goes to...
Version 1.5.1 This is a mainly cosmetic update to version 1.5, nevertheless well worth installing.
SDR Television This release is actually beta 6 with a few small updates, so I've left the beta 6 text here. I hope to start working on this in November 2025, adding the Gardner timing error detection which should improve the decoding with low SNR. Downloads are at the bottom of this page.
Hello Again I'm now back to 90% SDR Console support, so here's the first beta for at least eight months. Scroll to the bottom for a link to the beta kit. The source is fully archived, so crash dumps can be analysed.
SDR Television Improved phase detection at the start of each frame (SOF, PLS) which in turn improves sensitivity. Added 2,000 ksps receive, confirmed as working with GB3NQ. Sensitivity still not as good as a Serit 4334 NIM as used in the MiniTioune receiver, what's missing is synchronisation timing, I will be using Gardner timing error detection (TED). This will be added in Q1, 2026 when this project is extended for terrestrial use. Downloads are at the bottom of this page.
SDR Television Found and fixed an unused massive memory allocation (up to 10GB), may have caused systems to freeze. Fixed fatal bug in matched filter array allocation. Changed the default transmit bandpass shaping filter roll-off to 0.20 in transmit and receive. Please look at the images below and apply the change. SDR Pluto Now show the AGC gain and RSSI. Added Default link to select the recommended gain - Fast Attack, 0dB visual. Known Problems Add support for tracking transmissions with (?) non-standard PCR data, example is G8GKQ. Using Pluto & variants, sensitivity is not as good as a NIM (hardware tuner). Will compare with SPECTRAN ECO in a week or so.
Unexpected Beta #4 I wasn't planning to release another beta, but there was an error with a download link in the Blog post for Beta #3, also a few worthwhile improvements have been made, so here I go.
