xSDR Crowdfunding Opens: A Compact M.2 Software-Defined Radio

Wavelet Lab has launched a crowdfunding campaign on Crowd Supply for the xSDR, the smaller of two planned M.2 software-defined radio modules. It is built around Lime Microsystems' LMS7002M field-programmable RF chip — the same one that powers the LimeSDR family — paired with an AMD Artix-7 XC7A35T FPGA.

Positioned as the "extended" follow-up to the earlier uSDR, the key specs are:

  • Tuning range: 30 MHz – 3.8 GHz
  • Sampling rate: up to 122.88 MSPS
  • Channels: 2×2 MIMO TX/RX
  • Form factor: M.2 (drop into SBCs, laptops, desktops, and servers)
  • Software: wsdr.io — browser-based configuration and cloud collaboration

The module-only early-bird price is $549. Wavelet Lab also plans a future sSDR variant that adds a Lime LMS8001 up/down-converter, pushing the tuning range to 30 MHz – 11 GHz.

A Microcontroller-Powered Analog TV Transmitter

Maker Kris Slyka wanted to do something with a second-hand CRT TV — but it had no video input, just an antenna. Analog broadcasts in his area shut down more than a decade ago.

Rather than mod the TV for composite input or buy an RF modulator, he decided to build his own RF modulator out of a single STMicroelectronics Nucleo-G431KB dev board, built around the STM32G431. The chip's internal op-amps support input muxing, which lets them switch between signals quickly enough to act as a crude RF modulator.

The end result is a compact custom PCB that transmits analog audio and video — though output power is low enough that you have to wrap a wire around the TV's antenna to see or hear anything other than static. Full write-up on Kris's website.

Daniel Estévez Re-Decodes ESCAPADE Mars Telemetry

Back in November, Daniel Estévez recorded X-band telemetry from the ESCAPADE Mars twin-orbiter mission using the Allen Telescope Array and decoded the signal with GNU Radio. He has now revisited the recording for a deeper analysis:

  • APID 520 — asynchronous log messages, ASCII payloads
  • APID 620/621/622/623 — ASCII strings, likely task names and states
  • APID 730 (active only on ESCAPADE-Blue) — an ASCII file path plus numeric data
  • APID 740 — used for downlinking files
  • APID 6084/6423 — quaternion attitude data

Full write-up and downloadable data on Daniel's website.

tetraspot: Raspberry Pi 5 + SDR = Open-Source TETRA Base Station

Marcin Brzozowski has shared a work-in-progress project called tetraspot that turns a Raspberry Pi 5 and an SDR into a TETRA (the digital trunked-radio standard used by emergency services, public safety, and transport across Europe and beyond) base station.

What the Pi 5 currently handles:
- Voice calls (group + private, simplex and duplex)
- SDS messaging (TETRA's SMS equivalent)
- Terminal authentication
- Location reporting
- Group scanning
- Web management UI for audit logging and configuration
- Network-bridging plugins to other protocols

The next hardware step is swapping the SDR for a more capable unit plus a Class-A amplifier to push it toward a full-size base station. The software is in alpha and will be open-sourced once polished.

Osmocom CNI Updates

The Osmocom team has rolled out updates to its cellular network infrastructure (CNI) stack:
- libosmocore 1.13.0 — extensive fixes and improvements in osmo_io, Gsmtap, and logging; log targets default to non-blocking synchronous mode; new feature-detection flags; Emscripten build support and a JS callback logging backend
- osmo-bts 1.11.0 — bug fixes and improvements