Lime Microsystems has published the first details of LimeNET Micro 2.0, a radio front-end carrier board for LimeSDR XTRX and Raspberry Pi Compute Module 4 (CM4), which is used as the basis of the 5G network-in-a-box developed in partnership with Vodafone.

The new LimeNET Micro 2.0 design brings increased performance, plus greater flexibility and upgrade potential thanks to a more modular approach, Lime Micro claims. The design leverages the Raspberry Pi CM4 and LimeSDR XTRX for their respective computing and RF features, but could also be used with future compute and SDR modules. This current combination enables 2×2 MIMO operation and with PCIe x1 Gen 2 SDR interfacing, representing a significant upgrade from the SISO-only capable original LimeNET Micro and its USB 2.0 SDR interface.

As with the previous-generation LimeNET Micro, the updated 2.0 design features a high performance OCXO and this can be disciplined by not only GPS but also IEEE 1588 Precision Time Protocol (PTP). The board features gigabit Ethernet connectivity and provides access to USB, HDMI, and MIPI CSI and DSI, amongst other Compute Module inputs and outputs. The board also integrates a new RF front-end module, which features drivers for increased power output, LNAs for improved receive performance, and SPDT switches that provide support for both FDD and TDD modes of operation.

Further details will be provided in due course; interested parties can sign-up for updates via the Crowd Supply pre-launch page.

Vileer, best known for the Pi-Cast Raspberry Pi-powered keyboard, video, and mouse (KVM) remote control platform, has revealed the first images of a prototype third-party case for the LimeSDR Mini 2.0 — offering active cooling for sustained use in hot environments.

“Finally got some time to work on the Lime-AC-Case 2.0 for the LimeSDR Mini 2.0,” Vileer writes of the case, which follows an earlier design compatible with the original LimeSDR Mini. “The 3D print prototypes work great. Because all factories are closing business for the Chinese New Year, we have to wait until the end of the Feb to make the CNC ones.”

Designed to be made from aluminium, the unofficial case accessory provides both passive and active cooling for a LimeSDR Mini 2.0 — the former from the metal of the case itself with fins milled into its exterior to increase the surface area and the latter from a compact blower-type fan built into the case. This latter feature may prove useful for anyone using the LimeSDR Mini 2.0 for heavy workloads in high ambient temperatures, though shouldn’t be necessary for general use.

The prototypes images are available on Vileer’s Twitter thread.

Despite having landed upside-down, the Japan Aerospace Exploration Agency (JAXA) Smart Lander has successfully launched its LEV-1 and LEV-2 probes onto the surface of the moon – and work is underway on receiving and decoding signals from JS1YMG, an amateur radio operated by the JAXA Ham Radio Club (JHRC).

“JS1YMG for LEV-1 […] has been transmitting Morse code on 437.41MHz since January 19,” John E. Ross, editor of the ARRL Letter, writes in the latest issue. “The probe uses a 1W UHF antenna with circular polarization and is transmitting ‘matters related to amateur business.’ It’s unclear how long signals will be heard. JAXA has said that SLIM was not designed to survive a lunar night, which lasts about 14 days, and is due to return in a few days.”

Daniel Estévez is among those receiving and attempting to decode signals from the lander. “The information about the telemetry signal of LEV-1 is scarce. The IARU coordination sheet contains other clues, such as the mention of PCM/PSK/PM, CW, and bitrates of 31, 31.25 and 32 bps, but not much else. Regardless of the mention of CCSDS [the Consultative Committee for Space Data Systems], I have found that the signal from LEV-1 is quite peculiar.

“Norbert DL8LAQ has figured out how to read the Morse code. It turns out that it is inverted: the ‘dahs’ and ‘dits’ are represented by a low amplitude on the residual carrier, and the gaps by a high amplitude. I don’t know what was the reasoning behind this, since when one listens to the residual carrier, what is heard would be the opposite of what one expects.”

Daniel’s full write-up is available on his website, and continues to receive updates as the efforts progress.

Jean-Michel Friedt has presented a talk on a “covert” ground-based synthetic aperture radar built using a software-defined radio to pick up changes in signals from an off-the-shelf Wi-Fi dongle to track landslides and other slow movements.

“Using a Wi-Fi emitter as radio frequency source illuminating a scene under investigation for slow movement (e.g. landslides), a Ground-Based Synthetic Aperture RADAR (GB-SAR) is assembled using commercial, off the shelf hardware,” Jean-Michel writes in summary of the talk. “The dual-channel coherent Software Defined Radio (SDR) receiver records the non-cooperative emitter signal as well as the signal received by a surveillance antenna facing the scene.

“Spatial diversity for azimuth mapping using direction of arrival measurement is achieved by moving the transmitter and receiver setup on a rail along a meter-long path – the longer the better the azimuth resolution – with quarter wavelength steps. The fully embedded application runs on a Raspberry Pi 4 single board computer executing GNU Radio on a Buildroot-generated GNU/Linux operating system.”

The talk was given at FOSDEM 2024 earlier this month, and has been published on the event website; full documentation is available on GitHub.

Sylvain Azarian, meanwhile, has presented on the topic of accelerating signal processing for software-defined radio work using a computer’s highly-parallel graphics processing unit (GPU) – borrowing tricks used by on-device machine learning projects.

“GPU processors have become essential for image or AI [Artificial Intelligence] processing. Can they bring anything to real-time signal processing for SDR applications? The answer is yes, of course, but not all classic algorithms (FIR, DDC, etc.) can be used ‘as is,’ sometimes a different approach must be taken,” Sylvain explains.

“In this presentation, I will share the solutions that I implemented to achieve multi-channel DDC [Digital Downconversion] on [an] NVIDIA Jetson GPU and will make a comparison with ‘classic CPU’ approaches.”

Sylvain isn’t the only one looking at using a computer’s GPU for SDR-related acceleration: back in July 2022 we reported on Luigi Cruz’ efforts to add GPU acceleration to GNU Radio, which followed work on using NVIDIA’s CUDA general-purpose GPU (GPGPU) offload framework to accelerate a multi-channel FM demodulator.

Sylvain’s talk was also presented at FOSDEM 2024, and is again available with slide deck on the event website.

Gqrx, the open-source software defined radio receiver software built atop GNU Radio and the Qt GUI toolkit, has a new release with a difference: it’s compatible with Microsoft Windows, as well as Linux and Apple Mac systems.

“New: Experimental Windows binary release,” Gqrx maintainer Clayton Smith writes of the new release – which, admittedly, supports only a single type of software-defined radio dongle, but has the potential to introduce the software to an entirely new audience.

A popular package, Gqrx has previously been available exclusively for Linux and Apple Mac systems — though, as an open-source package, it’s possible to build it for other platforms if you’re willing to put in the effort. Gqrx 2.17.4, though, comes with a Windows binary as standard – along with an AppImage for Linux systems and a DMG installer for macOS.

While the Linux and macOS versions support a broad array of SDR hardware through gr-osmosdr, though, the experimental Windows release only supports RTL-SDR hardware at the time of writing.

The latest release, along with the full source code, is available on the Gqrx GitHub repository.

The SatDump project, which aims to simplify decoding data received from orbital satellites, is also celebrating a new version with the release of SatDump 1.1.4 – adding a multi-mode setting to the scheduler, among other new features.

“It might still be winter, but that hasn’t cooled down SatDump’s pace of development,” the SatDump team writes of the new release. “The most notable change this time around are the improvements to the autotrack/scheduler functionality.

“Previously, SatDump the scheduler could only decode one downlink at a time. This was a problem: what if you have an omnidirectional antenna and there are multiple satellites in the sky at once? Or: what if you want to get NOAA APT and DSB at the same time? Before, this was impossible – but now you can do it! By enabling ‘Multi Mode,’ all configured pipelines will run, even if more than one satellite is overhead at a given time.”

Other changes include the addition of a tuner for TUBIN raw mode, ESA Cluster-IIFM’s S-Band downlink, new pipelines for Peregrine X-Band TLM, the IM-1 moon mission, and PRETTY S-Band, support for theming the user interface, and enhancements to the Android port for improved performance through the use of OpenCL for GPU-accelerated imagery projections.

A full changelog is available on the SatDump website, while the project’s source code and latest binaries are available on GitHub under the reciprocal GNU General Public License 3. Existing users automating via the command-line interface are advised that the autotrack settings have changed, and that configurations may need to be updated as a result.

Finally, Osmocom has announced the opening of registration for and a call for participation in OsmoDevCom 2024, which returns after an extended pandemic-related break this May at the Van Der Valk Hotel Berlin Brandenburg.

“After several years of break since the COVID-19 pandemic hit, it is my great pleasure to finally announce OsmoDevCon2024, our (previously annual) Osmocom Developer Conference for developers, by developers,” writes Harald “LaForge” Welte of the event. “Contrary to our past OsmoDevCons (which have all been rather low budget, grass roots events), [I] felt that particularly after the long COVID-related break, it would be nice to do something slightly more fancy: Stay together with the entire group for four days, in a conference hotel.

“If you have contributed to Osmocom projects in the past (writing code, funding, documentation, packaging or related activities) you are eligible to attend. At the same time, the Call for Proposals is open: I’m sure after several years of a break, everyone must have hacked on (or learned about) many exciting things they would like to share. Any and all proposals are greatly appreciated.”

Harald’s full post is available on the Osmocom website, with event details on the wiki page – where those interested in attending, with or without presenting, can register and submit their proposals.