Gabe Emerson, of YouTube channel “saveitforparts,” has built a low-cost augmented reality system which lets you peer into the skies and see satellites as they pass – acting as a microwave-frequency camera.
“I’ve dabbled in radiotelescopes before, mostly as a way to use old TV satellite dishes,” Gabe explains. “However, this time I took a satellite dish and turned it into a microwave “camera”, able to create images in the Ku band!
“The dish I’m using is a ‘Tailgater’ model, which is another gadget I’ve experimented with before. The particular model I’m using has a USB console port, allowing serial commands to be sent from a Linux or Windows PC. I was able to automate the motor and receiver commands, driving the dish through a set of azimuth and elevation positions while recording the signal strength.”
The Tailgater satellite dish, originally built for mobile use on the backs of vehicles, is connected to a PC through USB and sent on a scan of the skies — recording Ku band signal strength as it goes. The data is then visualised as a heat map, and overlaid on panoramic photographs as an augmented reality illustration of a satellite’s path across the skies.
“This system can also be used to track down RF leaks,” Gabe notes. [Like this] indoor scan of my office, overlaid on a panoramic photo of the room. A microwave leak can immediately be seen coming from my poorly-shielded computer tower in the lower right.”
More information is available in Gabe’s blog post, while source code for the project – if you have a Tailgater dish to hand – is available on GitHub.
Dave “G8GKQ” Crump, chair of the British Amateur Television Club (BATC), has teased an upcoming new feature for the LimeSDR Mini-powered Portsdown platform: a radio frequency power meter for sun noise monitoring.
“[I’ve been] putting the finishing touches to a radio frequency power meter that uses a Raspberry Pi 4 and [a] Lime Micro LimeSDR Mini to measure the level of sun noise received by a dish aerial,” Dave explains. “[It’s] part of the BATC Portsdown project.”
The new feature comes a month after Dave unveiled an upgraded version of Portsdown, a platform designed to make it easy to begin experimenting with amateur digital television transmission, which adds compatibility with the new LimeSDR Mini V2 — an upgraded replacement for the original LimeSDR Mini which retains its predecessors features but packs a much larger FPGA with support for open-source toolchains, opening it up for use in a variety of projects.
A screenshot of the work-in-progress project is available on Dave’s Twitter account.
Developer Vasya Pavlov has been working on using a software-defined radio and GNU Radio to experiment with Wi-Fi — performing “black box optimisation” to fine-tune signal quality.
“I’ll share my experience in adjustment of [a] Wi-Fi physical channel,” Vasya writes by way of introduction to the project. “The channel was implemented on a software defined radio (SDR) platform. Wi-Fi looks like a very complicated thing standardised over hundreds of pages. Could a non-expert with PC and a couple of $100 devices somehow improve it?
“My intention was to find a mathematical framework for such a triage of complicated [GNU Radio] projects. If useful, such a functionality could be wrapped in a standard [GNU Radio] block. I took five parameters for optimization, these were: frequency, sensitivity of encoder/decoder, transmitter’s IF gain, receiver’s IF and VGA gains. Gaussian processes were engaged to process noisy and time-consuming channel quality measurements. The work results could be used to finely adjust Wi-Fi channel quality.”
Vasya’s full write-up is available on Habr, with source code published to GitHub.
Pseudonymous maker “TekMaker” has put together an experimental magnetic loop antenna, controlled via an Arduino microcontroller — and has published the source code for others to try.
“The intention is to build a mag loop development system where I can swap elements and do comparisons. So I will make everything pluggable or reconfigurable,” TekMaker explains. “I built a prototype using an Arduino Uno, but I wanted to have soldered connections so I rebuilt in on a prototype board specifically designed for Arduino Nano ([with] wider spacings in the centre) and installed a Arduino Nano Every that I had spare.
“The secret to a good mag loop is a variable capacitor form an old valve radio. This will handle the sort of voltages involved up to maybe 25W. I am QRP at 5W so not big deal. Sure enough a silent-key (amateur operator who has died) son was advertising some assorted parts, one box contained a couple of air dielectric capacitors. I set off my my motorbike into deepest Staffordshire last Autumn and acquired them.”
A write-up of the work-in-progress project is available on Instructables, accompanying a YouTube video on the topic. The Arduino sketch source code, meanwhile, has been published to GitHub.
Self-described “science and technology enthusiast” Andrea Console has built a radio with a difference: it can switch between operating as a battery-free crystal radio or a regenerative receiver.
“Who doesn’t love simple receiver circuits? This is a super-simple crystal radio that doubles as a regenerative receiver,” Andrea explains. “Now that operational AM medium-wave transmitters are a rarity, the fact that it works in the FM broadcast band is a plus. Its housing is a small cheese box.
“An interesting thing I discovered during my [research] was that you could also listen to FM stations with the same circuit you can use for AM. This discovery is a game-changer because it is not easy to design an FM detector that needs no power, and – at least in Europe – it is unlikely to live close to an AM transmitting station (there is only a handful still operational).
“[Some] would say this is not a crystal radio because it does not employ a diode,” Andrea says of his design. “I personally disagree as – in my understanding – a crystal radio is just a receiver that does not require power. The MOSFET here does the same job as the old galena crystal of rectifying the incoming waveform.”
Andrea’s full project write-up is available on Hackaday.io.
The Telecom Infra Project (TIP) has broken with tradition and begun charging for membership, though “Software Participation” memberships are still available for qualifying software engineers free of charge.
Founded in 2016, TIP boasts over 500 member organisations all working on opening up telecommunications technology – from developing and testing open radio access network (open RAN) systems to mmWave networks, open optical and packet transports, open Wi-Fi technologies, and even power and connectivity projects. At the time of its launch, membership was free – but that has now changed.
Speaking to Fierce Wireless, TIP executive director Attilio Zani confirmed the move which sees the full membership tier charged at $10,000 per year (around £8,000). A lower “Associate Participation” membership is charged at $2,500 per year (around £2,000) but does not provide access to hardware-focused project groups, while the “Software Participation Tier” – aimed at individual contributors – is free to join.
Attilio has claimed that the move is designed to increase the organisation’s funding but without setting the bar high enough to prove a barrier to participation.
More details on the new membership tiers are available on the TIP website.
The UK government’s Department for Science, Innovation, & Technology (DSIT) has published a policy paper on the nation’s approach to radio-frequency spectrum – offering “a spectrum vision for the coming period.”
“Spectrum is an increasingly important and valuable finite national resource. The devices and services that depend on spectrum now underpin almost every aspect of our economic and social lives,” the statement reads. “Its use is also of strategic importance to addressing major upcoming policy challenges, from our digital connectivity ambitions and the future of broadcasting to the energy transition and delivery of the National Space Strategy and Integrated Review.
“This statement is intended to ensure that, across government, we have the right policy framework in place to maximise the overall value of spectrum use to the UK, while supporting wider policy objectives. It sets out a new strategic vision and principles for spectrum policy, with a focus on innovation in the use and management of spectrum to create greater opportunities for growth and societal benefits through increased access to spectrum.”
That vision includes hints of “a new vision to maximise spectrum value” with “a renewed focus on innovation in wireless technology,” a target of nationwide coverage of standalone 5G New Radio connectivity by 2023, and plans for a new framework for spectrum use in the public sector following the closure of the Public Sector Spectrum Release Programme late last year.
The full document is available on GOV.UK now.
Software developer and vintage computing enthusiast John Newcombe has shown off a somewhat unusual use for packet radio: playing Colossal Cave Adventure on a DEC PDP-11 minicomputer.
“A not so quick session to show how you can connect to a PDP-11 over packet radio in order to to play Colossal Cave Adventure,” John explains of his video, referring to Will Crowther’s classic 1976 text adventure running on a Digital Equipment Corp. PDP-11 16-bit minicomputer.
“The session was recorded using [a] Mac connected to my Kenwood TH-D72, which in turn connects to my Node (TSTAR:G6AML-7).”
The full video is available on John’s YouTube channel GlassTTY, with more information on his various experiments available on his website.
Coalfire senior security consultant Rick Osgood, on the other hand, has a warning about hooking ham radio equipment up to computers — in that they can provide an unexpected vector for attacks.
“Hackers have been breaching computer system defences for more than half a century, and the networks they use to exploit those weaknesses have been around for far longer than that,” Rick explains by way of introduction. “With the internet replacing most wirelines and wavelengths, and with the rise of cybercrime sophistication from petty thieves to organized nation-states, the threat landscape has exploded over the last 20 years.
“Yet one of the oldest network protocols – amateur or ‘ham’ radio – is still used to this day in emergency communications during times of war and disaster, and to this day can still be used in binary exploitation.
“I’ve been messing around with packet radio and various digital modes on and off for years and have wondered if any vulnerabilities exist that could allow an attacker to obtain remote code execution through the airwaves,” Rick continues. “I always thought it was a fun idea to be able to hack a computer that isn’t even hooked up to the internet. Many ham programs are written by enthusiasts and are quite old, so it seemed likely that there would be exploitable vulnerabilities.”
Rick’s full investigation series is available on the Coalfire blog now.
Finally, engineer Neil Smith, of the Machining and Microwaves YouTube channel, was approached by the BBC with an unusual request: to build a working replica of the infamous 1940s “Great Seal Bug.”
“The Bug was planted in the US Ambassador’s residence at 10 Spasopeskovskaya Square in Moscow near the end of World War Two in 1945,” Neil explains. “It ran WITHOUT ANY BATTERIES OR MAINS POWER for the next SEVEN years, leaking the secret conversations from the Ambassador’s study in Spaso House to the NKVD.
“It’s a masterpiece of spycraft and psyops and technical engineering skill. An elegant solution produced under extreme conditions. It’s also a classic tale of what spies and spying and counter-espionage and technical security countermeasures used to be all about. I uncover a lot of disinformation, some of it intentional, some of it resulting from group-think and assumptions.
“Now you may have heard the story before, and have heard the technical explanations and the politics and history,” Neil continues. “I’m the sort of obsessive nerd that has to MAKE things to test them out properly, and I try to do my research from primary sources rather than repeating the twaddle and nonsense that sometimes surrounds Zlatoust, the Great Seal Bug.”
Neil’s full video is available on his YouTube channel now, while the replica can also be seen in the latest series of the BBC’s The Secret Genius of Modern Life presented by Professor Hannah Fry.