Radio Hacks

1336 Articles

Radio Apocalypse: The BBC Radio Program That Could(n’t) Have Started WWIII

September 21, 2023 by 28 Comments

Here’s a question for you: if you’re the commander of a submarine full of nuclear missiles, how can you be sure what not receiving a launch order really means? If could — and probably does — mean that everything is hunky dory on land, and there’s no need to pull the trigger. Or, could radio silence mean that the party already kicked off, and there’s nobody left to give the order to retaliate? What do you do then?

One popular rumor — or “rumour,” given the context — in the UK holds that BBC Radio 4, or the lack thereof, is sort of a “deadman’s switch” for the Royal Navy’s ballistic missile subs. [Lewis (M3HHY)], aka Ringway Manchester on YouTube, addresses this in the video below, and spoiler alert: it’s probably not true.

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New LoRA Distance Record: 830 Miles!

September 15, 2023 by 51 Comments

The LoRa radio communication system is useful for low-bandwidth communication, and as many readers will be aware its special skill lies in delivering long range. For most of us that range tops out at a few miles, but pushing the limits of what is possible for LoRa has resulted in some significant records falling. Most recently this has reached an impressive distance of 1336 kilometres, or 830 miles.

The record in question was set from near the Portuguese coast, from where LoRa beacons on a fishing boat and its buoys were able to open up a gateway on the Spanish Canary islands. The conductive surface of the sea makes an excellent aid to propagation, and from amateur radio experience we’d guess that tropospheric conditions aided by the summer weather would have something to do with it too.

Radio amateurs on those coasts and islands chase those conditions and live in hope of making a rare UHF contact across the ocean to the Americas or the Caribbean. The difference in their respective frequency allocations notwithstanding, we wonder whether the same might be possible using LoRa given a fortuitous atmosphere. We’re not quite sure whether a set of dual-band LoRa gateways could be made to test this idea though.

This record breaks a previous one set between Germany and Poland. If you think you’ve seen a far greater LoRa record here before you’d be correct, but only in the modulation scheme and not the frequency.

ESP32 Drives Tiny FM Radio

September 14, 2023 by 21 Comments

Even as music streaming services and podcast apps dominate most of our listening time, it’s still a great idea to keep a radio on hand, if for nothing else than in emergency situations. After all, blizzards, hurricanes, and other natural disasters can quickly take out both home and mobile Internet access. If you’d like to have an FM radio with the absolute smallest footprint, take a look at this one built around an ESP32.

While the radio uses the ESP32 as the main control board hosted by a TTGO T-Display board which adds a 1.14 inch ST7789V IPS panel, it also makes use of the TEA5767 chip for handling the FM radio signals. As [Volos Projects] has it programmed, the ESP32 stores five preset channels which can be toggled using two buttons at the bottom of the device. There’s also some circuitry to handle output to headphones or a stereo.

For making the radio even smaller, some of the audio processing could be done on the ESP32 instead, although its much simpler to take a slightly larger footprint and offload this to an audio processing chip. Since the source code for this project is open, modifications could be done including adding seek/tune functionality instead of relying only on presets. If you’re not building this for emergencies, though, and your entire area is dominated by cookie cutter corporate-owned radio stations, an ESP32 with an internet connection is great for accessing better radio stations around the world.

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Portrait Of A Long Wave Station In Its Twilight Years

September 13, 2023 by 25 Comments

There’s a quirk of broadcasting in Europe left over from the earliest days of the medium, which our American readers may not have encountered. As well as the familiar AM band, Europeans and Africans also have a so-called long wave band, on which you’ll find AM broadcast stations between about 150 and 280 kHz. Long wave transmissions were an ideal solution in the 1920s and 1930s to the problem of achieving national coverage from a single transmitter, and were widely used by state broadcasters. In an age of digital streaming they are increasingly irrelevant, and [Ringway Manchester] takes a look at one of Britain’s last long wave transmitter sites at Droitwich not too far from Birmingham.

The site covers around 50 acres, and is home to a variety of both medium wave (AM, for Americans), and a single long wave transmitter carrying BBC Radio 4 on 198 kHz. As he takes us through its history in the video below the break we hear a rundown of most of the major events in British broadcasting, while few Brits will have visited this unassuming field it’s likely most of us will have listened to something sent from here.

The long wave antenna is a T-shaped affair strung between two masts. We’re guessing that the radiator is the vertical portion, with the bar of the T forming a capacitance with the ground to make up for the radiator being a fraction of the 1515 meter wavelength. The video is something of a tribute to this once-vital station, as the Radio 4 transmissions are likely to stop in 2024 and the medium wave ones over the following years. We have to admit to catching our BBC transmissions online these days, but we still have to admit a pang of sadness at its impending end.

This reminds us, we’ve taken a fond look at AM radio in the past.

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Balloon-Eye View Via Ham Radio

September 11, 2023 by 22 Comments

If you’ve ever thought about launching a high-altitude balloon, there’s much to consider. One of the things is how do you stream video down so that you — and others — can enjoy the fruits of your labor? You’ll find advice on that and more in a recent post from [scd31]. You’ll at least enjoy the real-time video recorded from the launch that you can see below.

The video is encoded with a Raspberry Pi 4 using H264. The MPEG-TS stream feeds down using 70 cm ham radio gear. If you are interested in this sort of thing, software, including flight and ground code, is on the Internet. There is software for the Pi, an STM32, plus the packages you’ll need for the ground side.

We love high-altitude balloons here at Hackaday. San Francisco High Altitude Ballooning (SF-HAB) launched a pair during last year’s Supercon, which attendees were able to track online. We don’t suggest you try to put a crew onboard, but there’s a long and dangerous history of people who did.

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It’s Numbers All The Way Down With This Tape Measure Number Station Antenna

September 6, 2023 by 12 Comments

For all their talk of cooperation and shared interests, the nations of the world put an awful lot of effort into spying on each other. All this espionage is an open secret, of course, but some of their activities are so mysterious that no one will confirm or deny that they’re doing it. We’re talking about numbers stations, the super secret shortwave radio stations that broadcast seemingly random strings of numbers for the purpose of… well, your guess is as good as ours.

If you want to try to figure out what’s going on for yourself, all you need is a pair of tape measures and a software defined radio (SDR), as [Tom Farnell] demonstrates. Tape measure antennas have a long and proud history in amateur radio and shortwave listening, being a long strip of conductive material rolled up in a convenient package. In this case, [Tom] wanted to receive some well-known numbers stations in the 20- to 30-meter band, and decided that a single 15-meter conductor would do the job. Unlike other tape measure antennas we’ve seen, [Tom] just harvested the blades from two 7.5-meter tape measures, connected them end-to-end, and threw the whole thing out the window in sort of a “sloper” configuration. The other end is connected to an RTL-SDR dongle and a smartphone running what appears to be SDRTouch, which lets him tune directly into the numbers stations.

Copying the transmissions is pretty simple, since they transmit either in voice or Morse; the latter can be automatically decoded on a laptop with suitable software. As for what the long strings of numbers mean, that’ll remain a mystery. If they mean anything at all; we like to think this whole thing is an elaborate plan to get other countries to waste time and resources intercepting truly random numbers that encode nothing meaningful. It would serve them right.

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USB-C Power For Ham Radio

September 5, 2023 by 28 Comments

Even though manufacturers of handheld ham radios have been busy adding all sorts of bells and whistles into their portable offerings, for some reason, many of them lack a modern USB-C port. In the same vein, while some have USB for programming or otherwise communicating between the radio and a computer, very few can use USB for power. Instead , they rely on barrel jacks or antiquated charging cradles. If you’d like to modernize your handheld radio’s power source, take a look at what [jephthai] did to his Yaesu.

In the past, USB ports could be simply soldered onto a wire and used to power basically anything that took 5 VDC. But the radio in question needs 12 volts, so the key was to find a USB-C cable with the built-in electronics to negotiate the right amount of power from USB-PD devices. For this one, [jephthai] cut the barrel connector off his radio’s power supply and spliced in some Anderson power pole connectors so he could use either the standard radio charger or one spliced onto this special cable.

With this fairly simple modification out of the way, it’s possible to power the handheld radio for long outings with the proper USB battery bank on hand. For plenty of situations this is much preferable to toting around a 12 V battery, which was the method of choice for powering things like QRP rigs when operating off-grid.