Lime Suite v20.07.1 has officially launched, bringing a range of improvements to the LimeSDR-focused software bundle – including a fix for a bug which was causing quick tests of LimeSDR Mini boards to fail.
In its latest release, Lime Suite v20.07.1 repairs a recently-discovered bug which would manifest as intermittent failures when running the LimeQuickTest utility on LimeSDR Mini boards. While these failures would appear to suggest that the boards were themselves faulty, the cause was traced back to a simple configuration issue – now resolved, making Lime Suite v20.07.1 a must-have update for LimeSDR Mini users.
The new software release also adds initial support for the LimeRFE radio-frequency front-end, improvements for SoapySDR-based applications, and better support for GNU Octave. The latest release is also the first to come packaged for Canonical’s Ubuntu 20.04 Linux distribution, accessible via the SDR Drivers Personal Package Archive (PPA), with binary builds for other platforms available via GitHub.
More information on the update can be found on the MyriadRF blog.
Members of the British Amateur TV Club (BATC) have celebrated a milestone achievement: successful ‘barefoot’ transmission of digital TV signals using an unamplified LimeSDR Mini over a 16km signal path.
The BATC Portsdown project is designed to make digital television transmission accessible to all, courtesy of a turnkey system built around the LimeSDR Mini. Traditionally, however, Portsdown is used in partnership with a power amplifier to boost the signal – but a recent experiment by BATC member John G7GTT showed how this isn’t always necessary, even for relatively long-distance transmission.
John successfully transmitted DVB-S2 standard-definition digital TV signals with two audio channels over a 16km signal path to a repeater running at a 250 kS symbol rate, using the LimeSDR Mini’s barefoot 5mW output and a home-brew 15-element Yagi antenna. The repeater, meanwhile, was a BATC MiniTiourner linked to a Raspberry Pi 4 single-board computer.
More information, and a link to learn more about the Portsdown project, can be found on the Lime Microsystems website.
The M17 Working Group is attempting to “kick proprietary protocols off the airwaves” by offering “legitimately competitive” open-source alternatives for both voice and data use.
“Ham radio is about experimentation and learning, but almost all radios used by Amateurs today are closed source and proprietary. The protocols themselves are usually more accessible, but require proprietary bits to actually implement, such as the voice encoding software,” the Working Group writes of the M17 Project. “All current VHF+ digital radio protocols (D-STAR, DMR, Yaesu System Fusion, P25, …) use some form of AMBE voice codec — which is patent-encumbered and expensive to license, and certainly not available to the average ham.
“At the time these protocols were designed, AMBE was the only choice, but luckily, there is an excellent modern vocoder that is fully open — Codec2, by David Rowe.”
The M17 project is split into halves. The first, M17, is an effort to build an open-source and patent-free protocol stack based on open-source voice codecs and including digital data support – building atop David’s Codec2 work. At the same time, the team is working on an open-hardware handheld radio, the TR-9, which is designed to be fully compatible with the M17 standard.
More information can be found on the project website.
Radio amateurs across the globe have begun reporting contacts with Tianwen-1, the China National Space Administration (CNSA) mission to land a robotic spacecraft to Mars which launched in late July.
“Tianwen-1 signal while at 3.7 million km from Earth received with Lime SDR Mini,” writes Italian radio ham Supertrack in a series of Twitter posts tracking the mission’s signals as it gets further and further away from Earth. “Tianwen-1 probe now at almost 7 million km from Earth still with an impressive signal. Tianwen-1 morning check. Distance from Earth now 8.133 Million km.”
“Since Tianwen-1 transmits its own real time orbit state vectors in the telemetry,” Daniel Estevez notes in his own write-up of observations, “by comparing the vectors transmitted before and after TCM-1, and also by studying the Doppler observed by ground-stations on Earth, we can learn more about the manoeuvre.”
Those looking to do their own observations will find the signal analysis post of r00t.cz useful, while more information on the mission itself can be found on Wikipedia.
Those interested in QO-100 contacts, meanwhile, should check out a video from Tech Minds showcasing a home-brew dual-feed helix antenna designed specifically for covering both the 2.4 GHz uplink and 10 GHz downlink frequencies.
Dubbed the Ice Cone Feed, for its similarity to an ice-cream cone, the design by radio amateur Patrick DO8PAT features 3D printed parts – the files for which have been released on Thingiverse under a Creative Commons Attribution Non-Commercial No Derivatives licence – with a 4mm aluminium disc as a reflector mounted on an M10 bolt and spun using a column drill. The helix, meanwhile, is constructed from 10-16mm² copper wire using a 3D printed winding tool.
Tech Minds’ video walking through the printing, construction, and testing of Patrick’s antenna design is available on the YouTube channel.
Pseudonymous security researcher Aaron “Cemaxecuter” has published a video showcasing how to set up a GSM cellular network using a software-defined radio and the Osmocom communications stack running on the increasingly popular DragonOS SDR-focused operating system.
“This is going to be all included in the next DragonOS release,” Aaron notes in the video’s introduction, “hopefully this Thursday. At this point when I bring this online it is going to be transmitting,” they continue, a mere three and a half minutes into the video, “so make sure you take the appropriate precautions.”
The short, five-minute video demonstrates how easy it is to get started with Osmocom, and ends with a successful connection to an Android smartphone – though, Aaron warns, “adding the IMSI to the HLR is important, otherwise the phone will not be able to register to the network.”
The full video can be found on YouTube now.
Researchers at the Electronic Frontier Foundation have released a tool for detecting next-generation IMSI catchers operating on 4G cellular networks: the Crocodile Hunter.
“At Standing Rock, [EFF security researcher Cooper] Quintin took out his software-defined radio, scanning for abnormal signals, and opened up an Android app known for spotting IMSI catchers. He didn’t get any hits,” writes Cyberscoop’s Sean Lyngaas in his coverage of the project. “‘I had no idea what I was doing,’ said Quintin, a security researcher at the non-profit Electronic Frontier Foundation. He was using technology designed for 2G wireless networks, leaving him blind to IMSI catchers on 4G networks, if they were indeed there.”
The Crocodile Hunter is an effort to address that oversight. Released by the EFF under the GNU General Public Licence v3, The Crocodile Hunter forms the central pillar of a study on 4G/LTE cell site simulators – IMSI catchers, devices which track, without the consent of their owners, cellular devices as the move through an area.
Initially, radio support is limited, but the project’s source code is available on GitHub for those looking to extent it to cover additional devices – and DragonOS’ Aaron has already published a video demonstrating how to get the software up and running on the SDR-focused Linux distribution.
The Nyansat project is aiming to make satellite communications as accessible as possible, and has released a design for a ground station capable of automatically aligning and tracking an antenna to a satellite.
“With a few pieces of cheap equipment, some determination, and a computer, you too can receive signals from the sky,” the Nyansat team explains. “NyanSat is a guided challenge that walks you through building your own ground station to track satellites, receiving signals, understanding how data is encoded, and looking at images from space.”
The core of the Nyansat project is an open-source microcontroller board dubbed the Antenny, which drives a pan/tilt gimbal to which the antenna is attached – allowing it to both automatically locate satellites and to track them as they move across the Earth. The board is driven by an Espressif ESP32 microcontroller, and also features an inertial measurement unit (IMU) input, motor driver, and an optional OLED panel for visual feedback.
Full details, and a guide to building a Nyansat ground station, can be found on the official website.
The Tech Minds YouTube channel has published a guide to getting OpenWebRX, a tool for enabling remote access to software defined radio devices, up and running on a Raspberry Pi single-board computer.
“The original author of OpenWebRX abandoned the project towards the end of last year,” Tech Minds’ video explains, “but luckily for us it’s been taken over and is now more feature-rich than ever before. We’ll need a Raspberry Pi – anything greater than a Pi 3B+ should be okay to use. You’ll also need a microSD card, on which we’ll burn the image onto. You’ll also need an SDR receiver.”
The 16-minute video walks through all the major features of the software, including its in-built decoding and bookmark functions, as well as a step-by-step guide to running it on a Raspberry Pi. Those interested in running it on a different device, meanwhile, can find more information on the official OpenWebRX website.
Tech Minds’ video is available on YouTube now.
On a similar topic, SignalsEverywhere’s Sarah has published a guide to using SDRTrunk and Broadcastify to stream received radio traffic over the internet.
“I’ll be showing you how to set up your own Broadcastify feed,” Sarah explains in the video’s introduction, “so that way you can stream all of this radio traffic out to the general public.”
The video builds on an earlier post, showcasing how to use SDRTrunk to receive digital-mode P25 emergency service broadcasts. In the follow-up video, Sarah shows how the reception from SDRTrunk can be broadcast as a public safety channel on Broadcastify – though, as RTL-SDR notes, it comes with the warning that public rebroadcast of some talkgroups may be illegal in some jurisdictions.
The video is available now on the SignalsEverywhere YouTube channel.
Two rapidly-growing fields of technology are colliding with interesting results: 3D printing and radio-frequency communication, resulting in specially-printed conformal antennas designed to fit in any niche.
“The research and experimentation work of 3D printed conformal antennas has ramped up in recent years and has been a central research field at major research institutions,” Charles R. Goulding and Adam Friedman write in a joint piece for 3D printing specialist Fabbaloo. “Conformal antennas are important because antenna devices can attach to structures, fully integrating with that structure without producing any drag force on the object on which it’s attached.
“Most people think of an antenna as the structure that protrudes out of satellite dishes, however conformal antenna products implant antennas so those are not visible for human observation. This allows antenna devices to be implanted with small antenna elements which together can transmit signals and electromagnetic communication in the frequency range that is commonly known as the Ka band.”
The full article, which includes a video demonstrating nScrypt’s successful 3D-printed conformal antenna for drone use, can be found over on Fabbaloo.
Finally, RTL-SDR has brought our attention to two new decoders for images from the Fengyun03 and MetOp HRPT weather satellitess.
“I recently got FengYun decoding working after the release of my MetOp decoder a while ago,” writes Alan Aang254 of the project. “Since gr-hrpt wasn’t usable for Windows user without some major hassle, I made some standalone decoders (Windows builds included in the repo) for both MetOp and FengYun.
“Decoding is done by first demodulating with the included flowcharts or @petermeteor’s, then processed through the decoder which does Viterbi/Differential decoding. The output then needs to be deframed by MetFy3x or any other software that can do so.”
The decoders, plus stand-alone Windows binaries, can be found on the GitHub repository under the GNU Lesser General Public Licence v3.