Boston-based Wavelet Lab has launched a high-performance software-defined radio system dubbed the xMASS SDR, using Lime Micro LMS7002M-based modules to deliver 8×8 multi-input/multiple-output (MIMO) connectivity – or up to 16×16, by linking two boards.

“xMASS SDR is a modular, high-performance MIMO transceiver optimised for industrial, academic, and advanced software-defined radio (SDR) applications,” Wavelet Lab’s founders say of their creation. “It features 8 RX [receive] and 8 TX [transmit] channels that can be synchronised. Its modular design enables simple maintenance and facilitates the creation of high-order MIMO systems using well-established building blocks.”

The xMASS SDR is designed to house four of the company’s xSDR software-defined radio modules, each of which includes its own Lime Micro LMS7002M chip — delivering 2×2 MIMO per module for 8×8 per board. If you need more, two xMASS SDR boards can be chained together to offer 16×16 MIMO. Each board offers covers 30-3,800MHz, can deliver 60 mega-samples per second (MSPS) over eight channels or 100 MSPS over four, and includes a bifurcation mode to run as two independent 4×4 MIMO or four independent 2×2 MIMO systems.

The company is positioning the xMASS SDR as ideal for experimentation into high-end radio systems including 4G Long Term Evolution (LTE) and 5G New Radio (NR) cellular, and promises support for the Amarisoft cellular software stack as well as SRSRAN, SoapySDR, GNU Radio, and Lime Suite, with support for the new Lime Suite NG planned.

More information is available on the xMASS SDR Crowd Supply page, where units can be pre-ordered ahead of January 2025 shipping for $3,900 including the xMASS SDR board and four xSDR modules.

The crowdfunding campaign for the LimeNET Micro 2.0, a next-generation successor to the popular all-in-one LimeNET Micro software defined radio and edge computing platform, is now live.

“The new LimePSB RPCM carrier board is significantly more versatile than the previous version of LimeNET Micro,” explains Lime Micro’s Andrew Back of the second-generation design, “which was limited by its support for a less powerful compute module (CM3) and an integrated SISO [Single-Input/Single-Output] radio.”

Designed to offer higher performance than the original LimeNET Micro, the LimeNET Micro 2.0 takes the form of a carrier board designed to host a Raspberry Pi Compute Module 4 system-on-module and a Mini PCI Express (mPCIe) software-defined radio like the LimeSDR XTRX. With integrated RF front-end driver, clock network, and power handling, the idea is to have a single compact platform which can handle both radio and edge computing workloads in one.

Pricing for the LimeNET Micro 2.0 starts at $799, with free global shipping, for the carrier board alone; a Developer Edition bundle is priced at $1,699 and includes the carrier board, a LimeSDR XTRX card, and a Raspberry Pi Compute Module 4 SOM with 8GB of RAM, 32GB of eMMC storage, and a Wi-Fi/Bluetooth radio, plus a custom acrylic enclosure with built-in cooling fan. Finally, a 5G Deluxe Kit adds the Amarisoft cellular software stack, two 5G-capable smartphones, and 10 SIM cards, to deliver everything required to run a private 5G New Radio network.

More information is available on the LimeNET Micro 2.0 Crowd Supply campaign page; hardware is expected to begin shipping to backers at the end of November.

Developer Jan Dvořák has built a software-defined radio with a difference: it uses nothing more than a low-cost Raspberry Pi Pico microcontroller board and two passive components, yet delivers usable – if noisy – reception.

“I have never built a radio before,” Jan admits. “As a software developer I have had my share of building networking applications. Even ones that made use of Wi-Fi or cellular networks. But I have never really understood how those radios worked at the level where software met the electromagnetic field. On the transmitting side, it ends up being fundamentally pretty simple. Just toggle a GPIO [General-Purpose Input/Output] pin at the correct frequency, connect piece of wire as an antenna and get on the air. [But] receivers are hard.”

That didn’t stop Jan from attempting to build one. Having found existing projects which use field-programmable gate arrays (FPGAs), he set about doing similar on a general-purpose microcontroller – the Raspberry Pi RP2040, available as a bare chip for around $1 or on the Raspberry Pi Pico development board for $4.

Rather than using the chip’s on-board analogue to digital converter (ADC), Jan’s SDR taps into the RP2040’s programmable input/output (PIO) blocks – software-definable hardware blocks which run state machines independent of the main processor cores, which are left free to handling mixing and filtering from the PIO-based direct sampling receiver. The only other components required: a single resistor, a capacitor as a low-pass filter, and an antenna.

“Raw IQ samples are sent over USB CDC to my PC,” Jan says, “picked up by a small Python script, turned into TCP stream and processed with GNU Radio, which provides a nice graphical application called GNU Radio Companion that can be used to construct signal processing pipelines and output the audio to the system speakers. Yes, it’s noisy, but isn’t it still pretty cool that you can do that with a $1 general purpose microprocessor, two passive components, and an antenna?”

The project is documented on Jan’s website, with source code available under a fully-permissive public domain license.

The popular uSDR software-defined radio package for Windows has received a major update, which introduces a new IQ playback mode for improved timing – along with a reduction in memory usage and CPU load.

uSDR v1.7.0, its maintainers write in the new release’s patch notes, comes with an “advanced IQ playback mode,” designed to offer more precise timing and streaming functionality over the existing version. The new release also includes improved digital signal processing (DSP) routines, which combines with better memory management to reduce resource requirements – including lowering the CPU load of the software.

Another new features in the latest release is the addition of what the software’s maintainers describe as an “excellent ruler tool,” which is designed to make it easier to measure frequency and amplitude. These enhancements come on top of features added in the prior release, v1.6.0, including new IQ file playback options and a spectrum display mode to hold peaks with a zoom-and-pan plot.

The latest version of uSDR is available to download from SourceForge now.

Developer Ihar Yatsevich has designed a pocket-sized WSPR beacon which won’t break the bank, using Microchip’s popular ATmega328 microcontroller and a Silicon Labs Si5451 clock generator.

“WSPR (Weak Signal Propagation Reporter) is a digital radio communication protocol developed to study the propagation of weak signals over long distances, allowing radio amateurs to observe in real-time how far radio signals from a specific transmitter can travel,” Ihar writes by way of background to the project. “My interest in WSPR technology began with decoding WSPR messages via a WebSDR receiver, but I had no experience in transmission and wanted to try it.”

Ihar had previously experimented with a homebrew WSPR beacon using the SiLabs Si5351 clock generator and a NodeMCU ESP8266 microcontroller — but the rapidly-prototyped creation proved unreliable. “WSPR messages are successfully transmitted and decoded using a locally positioned SDR receiver, but I really dislike breadboard connections when using ready-made modules,” he explains. “As expected, I encountered issues: a poor contact, a slight nudge, and something falls off. Using such a tangle of modules as a finished device is completely impractical.”

The Microchip ATmega328 version of the build uses a custom-designed circuit board with the components permanently installed: the microcontroller, the clock generator, a GPS module, an amplifier, and a temperature-compensated crystal oscillator to eliminate frequency drift. Everything is housed in a small aluminium chassis, and provides a maximum output power of ~23dBm.

The project is detailed in Ihar’s Reddit post, with hardware design files and firmware source code published to GitHub under the GNU General Public Licence 3.

Canonical, the company behind the Ubuntu Linux distribution, has announced a beta release of Charmed Aether SD-Core – an automation solution for the Linux Foundation’s Aether open-source 5G core network software stack.

“Charmed Aether SD-Core is a set of Juju charms (open source software operators) that can automate the deployment, integration and lifecycle management of The Linux Foundation (LF)’s 5G core network software,” explains Canonical’s Serdar Vural. “This software is distributed under LF’s Aether directed fund project, which includes the Software-Defined Core (SD-Core) sub-project. Charmed Aether SD-Core makes it possible to operate a fully functional open source 5G core network on a Kubernetes system running on common off-the-shelf (COTS) hardware with full software automation.

“Businesses that need a private mobile network which they can fully own will now have a frictionless and cost-effective way to run a core network with built-in automation. Developers who are looking into integrating their software solutions and testing over a 5G network can set up their own environment with ease. Research institutions that specialise in 5G technologies but need an open source 5G mobile core that is easy to deploy and operate can immediately leverage Charmed Aether SD-Core.”

Charmed Aether SD-Core is available in beta now, though no date has been provided for its promotion to general availability; interested parties can read up on how to get started in Canonical’s documentation.

Astrophysicist Jack Burns has presented on a novel experiment which flips expectations on their head: recording the Earth’s radio waves from a receiver positioned on its moon.

“We viewed Earth as an exoplanet, or a planet orbiting another star,” Jack, co-investigator of the Radio wave Observations at the Lunar Surface of the photo Electron Sheath (ROLSES) experiment and professor emeritus at CU Boulder, explains. “That enables us to ask: what would our radio emissions from Earth look like if they came from an extraterrestrial civilization on a nearby exoplanet?”

The ROLSES platform was launched to the moon on board Intuitive Machines’ Odysseus lander, launched as part of the NASA Commercial Lunar Payload Services programme. Its arrival, though, was less than smooth – and while the lander made history, it also toppled onto its side after a failure in its laser-guided navigation system. “It was heroic for Intuitive Machines to land under these conditions,” Jack says, “and to deploy our antennas, take some data, and get that data back to Earth.”

Jack presented the project’s findings at the 244th Meeting of the American Astronomical Society earlier this month; a video recording is available alongside a supporting slide deck on the AAS website.

Electronics engineer and radio ham Guido “IW5ALZ” Giorgetti is working on a project to build a low-cost Automatic Packet Reporting System (APRS) iGate and Digipeater – powered by a Raspberry Pi Zero 2 W single-board computer.

Guido’s initial experiments revolved around using an Espressif ESP32 microcontroller and a NiceRF SA818 transceiver, but things didn’t go well. “After trying to receive some RF APRS messages on 144.8MHz to test RX capabilities,” the engineer explains, “I realised that the SA818v receiver hadn’t enough sensitivity. “So I ended up to a different solution, using: SA818v for transmitting; RTL2832 for receiving; Direwolf running on a Raspberry Pi Zero 2 W to decode received/encode transmitted APRS messages; a MAX98357 board to output audio waveform (AFSK1200 modulated APRS messages).

“The Raspberry Pi, by the I2S interface, send the modulated AFSK 1200 (Bell 202) APRS messages to the microphone input of the SA818v 144.8MHz transmitter. The RTL8232 board (tuned at 144.8MHz) is connected via USB to the Raspberry Pi, which decodes the APRS messages. The rtl_fm program configures and tunes (at 144.8MHz) the RTL2832 and demodulates narrow band FM. The Direwolf program, running on the Raspberry Pi, demodulates, decode, encode, [and] modulates the APRS messages and manages everything.”

The work-in-progress project is documented on Guido’s page.

Finally, noted reverse-engineer Ken Shirriff has turned his attention to a tiny piece of everyday radio technology many might not realise is even there: the MIFARE Ultralight Near-Field Communication (NFC) tags embedded in paper subway tickets.

“To use the Montreal subway (the Métro), you tap a paper ticket against the turnstile and it opens,” Ken explains. “The ticket works through a system called NFC, but what’s happening internally? How does the ticket work without a battery? How does it communicate with the turnstile? And how can it be so cheap that you can throw the ticket away after one use? To answer these questions, I opened up a ticket and examined the tiny chip inside.”

When Ken says “tiny,” he means it: the NFC chip is part of a plastic layer sandwiched within the paper ticket, but comes in smaller than a single grain of salt – small enough that Shirriff’s biggest concern during his processing of the part was losing it, rather than anything untoward happening with the boiling acids used to decapsulate the chip and reveal the circuitry within.

Using a high-powered microscope, Ken was able to trace out a number of blocks within the circuit: analogue, digital logic, and an EEPROM with a charge pump – the latter to boost the radio energy harvested from the reader by a foil antenna connected to the chip into a voltage high enough to actually write the EEPROM reliably. “It’s remarkable,” he concludes, “that these NFC chips can be manufactured so cheaply that they are disposable.”

Ken’s full write-up is available on his website.