The Singing Dentures Of Manchester And Other Places

October 12, 2025 by Jenny List 39 Comments

Any radio amateur will tell you about the spectre of TVI, of their transmissions being inadvertently demodulated by the smallest of non-linearity in the neighbouring antenna systems, and spewing forth from the speakers of all and sundry. It’s very much a thing that the most unlikely of circuits can function as radio receivers, but… teeth? [Ringway Manchester] investigates tales of musical dental work.

Going through a series of news reports over the decades, including one of Lucille Ball uncovering a hidden Japanese spy transmitter, it’s something all experts who have looked at the issue have concluded there is little evidence for. It was also investigated by Mythbusters. But it’s an alluring tale, so is it entirely fabricated? What we can say is that teeth are sensitive to sound, not in themselves, but because the jaw provides a good path bringing vibrations to the region of the ear. And it’s certainly possible that the active chemical environment surrounding a metal filling in a patient’s mouth could give rise to electrical non-linearities. But could a human body in an ordinary RF environment act as a good enough antenna to provide enough energy for something to happen? We have our doubts.

It’s a perennial story (even in fiction), though, and we’re guessing that proof will come over the coming decades. If the tales of dental music and DJs continue after AM (or Long Wave in Europe) transmissions have been turned off, then it’s likely they’re more in the mind than in the mouth. If not, then we might have missed a radio phenomenon. The video is below the break.

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Meshtastic: A Tale Of Two Cities

October 9, 2025 by Tom Nardi 84 Comments

If I’m honest with myself, I don’t really need access to an off-grid, fault-tolerant, mesh network like Meshtastic. The weather here in New Jersey isn’t quite so dynamic that there’s any great chance the local infrastructure will be knocked offline, and while I do value my privacy as much as any other self-respecting hacker, there’s nothing in my chats that’s sensitive enough that it needs to be done off the Internet.

But damn it, do I want it. The idea that everyday citizens of all walks of life are organizing and building out their own communications network with DIY hardware and open source software is incredibly exciting to me. It’s like the best parts of a cyberpunk novel, without all the cybernetic implants, pollution, and over-reaching megacorps. Well, we’ve got those last two, but you know what I mean.

Meshtastic maps are never exhaustive, but this gives an idea of node density in Philly versus surrounding area.

Even though I found the Meshtastic concept appealing, my seemingly infinite backlog of projects kept me from getting involved until relatively recently. It wasn’t until I got my hands on the Hacker Pager that my passing interest turned into a full blown obsession. But it’s perhaps not for the reason you might think. Traveling around to different East Coast events with the device in my bag, it would happily chirp away when within range of Philadelphia or New York, but then fall silent again once I got home. While I’d get the occasional notification of a nearby node, my area had nothing like the robust and active mesh networks found in those cities.

Well, they say you should be the change you want to see in the world, so I decided to do something about it. Obviously I wouldn’t be able to build up an entire network by myself, but I figured that if I started standing up some nodes, others might notice and follow suit. It was around this time that Seeed Studio introduced the SenseCAP Solar node, which looked like a good way to get started. So I bought two of them with the idea of putting one on my house and the other on my parent’s place down the shore.

The results weren’t quite what I expected, but it’s certainly been an interesting experience so far, and today I’m even more eager to build up the mesh than I was in the beginning.

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2G Gone? Bring It Back Yourself!

October 6, 2025 by Tyler August 25 Comments

Some parts of the world still have ample 2G coverage; for those of in North America, 2G is long gone and 3G has either faded into dusk or beginning its sunset. The legendary [dosdude1] shows us it need not be so, however: Building a Custom 2G GSM Cellular Base Station is not out of reach, if you are willing to pay for it. His latest videos show us how.

Before you start worrying about the FCC or its equivalents, the power here is low enough not to penetrate [dosdude]’s walls, but technically this does rely in flying under the radar. The key component is a Nuand BladeRF x40 full-duplex Software Defined Radio, which is a lovely bit of open-source hardware, but not exactly cheap. Aside from that, all you need is a half-decent PC (it at least needs USB-3.0 to communicate with the SDR, the “YateBTS” software (which [dosdude1] promises to provide a setup guide for in a subsequent video) and a sim card reader. Plus some old phones, of course, which is rather the whole point of this exercise.

The 2G sunset, especially when followed by 3G, wiped out whole generations of handhelds — devices with unique industrial design and forgotten internet protocols that are worth remembering and keeping alive. By the end of the video, he has his own little network, with the phones able to call and text one another on the numbers he set up, and even (slowly) access the internet through the miniPC’s network connection.

Unlike most of the hacks we’ve featured from [dosdude1], you won’t even need a soldering iron, never mind a reflow oven for BGA.

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Hard Hat Becomes Bluetooth Direction Finder

September 30, 2025 by Lewin Day 10 Comments

Have you ever wanted to find a Bluetooth device out in the wild while looking like the comic relief character from a science-fiction series? You might like Dendrite, the direction-finding hat from [SolidStat3].

Dendrite is intended for hunting down Bluetooth devices. It’s capable of direction estimation based on signal strength readings from four ESP32 microcontrollers mounted on an off-the-shelf hard hat. Each ESP32 searches for BLE devices in the immediate area and reports the apparent signal strength to a fifth ESP32, which collates readings from all units. It then runs a simple multilateration algorithm to estimate the direction of the device. This information is then displayed via a ring of addressable LEDs around the perimeter of the hat. White LEDs marking the direction of the detected device. The only problem? You can’t see the LEDs while you’re wearing the hat. You might need a friend to help you… or you can simply take it off to see what it’s doing.

Ultimately, this project is a useful direction-finding hard hat that would also make a perfect prop from an episode of Inspector Spacetime. We’ve covered direction finding in other contexts before, too. Meanwhile, if you’re cooking up your own innovative hard hat (or radio) hacks, don’t hesitate to let us know!

A Ham-Adjacent Portable Radio Repeater

September 26, 2025 by Bryan Cockfield 45 Comments

Although ham radio offers a wide array of bands to transmit on, not to mention plenty of modes to communicate with, not everyone wants or needs to use all of this capability. For those needing simple two-way communication services like FRS or GMRS are available (in North America) with much less stringent licensing requirements, and GMRS even allows repeaters to be used to extend their range beyond the typical mile or so. [Dave] aka [N8DAV] has built an off-grid simplex repeater that can travel around with him wherever he goes.

The repeater itself is based on a pre-built simplex repeater module, which means that it has to record an incoming signal and then play it back on the same frequency. Compared to a split frequency repeater which uses different frequencies for transmit and receive this can be a bit cumbersome but simplifies the design and the use. A Baofeng UV-5R is used to perform the actual radio duties paired to a 40 watt amplifier to extend the range as much as possible. It’s all packed into a Pelican-like case and set up with a large battery that could power it for a number of days, making it useful for camping, rescue, or other off-grid activities.

For those wondering why [Dave] is using his ham call sign instead of his GMRS one, all of the equipment in this build will work in either the UHF ham bands or the channels reserved for GMRS with minor adjustments, so it’s perfectly possible to use the setup for one’s preferred license. And, for those in other parts of the world without GMRS there’s a similar class of radio called UHF CB which might be able to support similar builds, but be sure to check your local jurisdiction’s laws before hooking something like this up. For an even longer-range radio repeater using similar equipment we’d recommend looking to the skies.

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Building Your Own DVB-S2 Receiver

September 22, 2025 by Lewin Day 9 Comments

Generally, a digital TV tuner is something you buy rather than something you make yourself. However, [Johann] has always been quite passionate about the various DVB transmission standards, and decided he wanted to build his own receiver just for the fun of it.

[Johann]’s build is designed to tune in DVB-S2 signals transmitted from satellites, and deliver that video content over a USB connection. When beginning his build, he noted it was difficult to find DVB reception modules for sale as off-the-shelf commercial parts. With little to nothing publicly available, he instead purchased a “Formuler F1 Plug & Play DVB-S2 HDTV Sat Tuner” and gutted it for the Cosy TS2M08-HFF11 network interface module (NIM) inside. He then paired this with a Cypress CY7C68013A USB bridge to get the data out to a PC. [Johann] then whipped up a Linux kernel driver to work with the device.

[Johann] doesn’t have hardcore data on how his receiver performs, but he reports that it “works for me.” He uses it in South Germany to tune in the Astra 19.2E signal.

We don’t talk a lot about DVB these days, since so much video content now comes to us over the Internet. However, we have still featured some nifty DVB hacks in the past. If you’re out there tinkering with your own terrestrial or satellite TV hardware, don’t hesitate to notify the tipsline!

The Inside Story Of The UK’s Great CB Petrol Scam

September 19, 2025 by Dan Maloney 28 Comments

Looking at gasoline prices today, it’s hard to believe that there was a time when 75 cents a gallon seemed outrageous. But that’s the way it was in the 70s, and when it tripped over a dollar, things got pretty dicey. Fuel theft was rampant, both from car fuel tanks — remember lockable gas caps? — and even from gas stations, where drive-offs became common, and unscrupulous employees found ways to trick the system into dispensing free gas.

But one method of fuel theft that escaped our attention was the use of CB radios to spoof petrol pumps, which [Ringway Manchester] details in his new video. The scam happened in the early 80s, only a few years after CB became legal in the UK but quite a while since illegal use had exploded. The trick involved a CB transceiver equipped with a so-called “burner,” a high-power and highly illegal linear amplifier used to boost the radiated power of the signal. When keyed up in the vicinity of dispensers with digital controls, the dispensing rate on the display would appear to slow down markedly, while the pump itself stayed at the same speed. The result was more fuel dispensed than the amount reported to the cashier.

If this sounds apocryphal, [Ringway] assures us that it wasn’t. When the spoofing was reported, authorities up to and including Scotland Yard investigated and found that it was indeed plausible. The problem appeared to be the powerful RF signal interfering with the pulses from the flowmeter on the dispenser. The UK had both 27 MHz and 934 MHz CB at the time; [Ringway] isn’t clear which CB band was used for the exploit, but we’d guess it was the former, in which case we can see how the signals would interfere. Another thing to keep in mind is that CB radios in the UK were FM, as opposed to AM and SSB in the United States. So we wonder if the same trick would have worked here.

At the end of the day, no matter how clever you are about it, theft is theft, and things probably aren’t going to go well for you if you try to pull this off today. Besides, it’s not likely that pumps haven’t been hardened against these sorts of attacks. Still, if you want a look inside a modern pump to see if you can find any weaknesses, have at it. Just don’t tell them where you heard about it.

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