Portable Multi-SDR Rig Keeps Your Radios Cool

September 3, 2024 by 10 Comments

With as cheap and versatile as RTL-SDR devices are, it’s a good idea to have a couple of them on hand for some rainy day hacking. In fact, depending on what signals you’re trying to sniff out of the air, you may need multiple interfaces anyway. Once you’ve amassed this arsenal of software defined radios, you may find yourself needing a way to transport and deploy them. Luckily, [Jay Doscher] has you covered.

His latest creation, the SDR SOLO, is a modular system for mounting RTL-SDRs. Each dongle is encased in its own 3D printed frame, which not only protects it, but makes it easy to attach to the base unit. To keep the notoriously toasty radios cool, each frame has been designed to maximize airflow. You can even mount a pair of 80 mm fans to the bottom of the stack to really get the air moving. The current design is based around the RTL-SDR Blog V4, but could easily be adapted to your dongle of choice.

In addition to the row of SDR dongles, the rig also includes a powered USB hub. Each radio connects to the hub via a short USB cable, which means that you’ll only need a single USB cable running back to your computer. There’s also various mounts and adapters for attaching antennas to the system. Stick it all on the end of a tripod, and you’ve got a mobile radio monitoring system that’ll be the envy of the hackerspace.

As we’ve come to expect, [Jay] put a lot of thought and effort into the CAD side of this project. Largely made of 3D printed components, his projects often feature a rugged and professional look that really stands out.

The First New Long Wave Radio Station Of This Millennium

August 11, 2024 by 34 Comments

The decline of AM broadcast radio is a slow but inexorable process over much of the world, but for regions outside America there’s another parallel story happening a few hundred kilohertz further down the spectrum. The long wave band sits around the 200kHz mark and has traditionally carried national-level programming due to its increased range. Like AM it’s in decline due to competition from FM, digital, and online services, and one by one the stations that once crowded this band are going quiet. In the middle of all this it’s a surprise then to find a new long wave station in the works in the 2020s, bucking all contemporary broadcasting trends. Arctic 252 is based in Finland with programming intended to be heard across the Arctic region and aims to start testing in September.

The hack in this is that it provides an opportunity for some low-frequency DXing, and given the arctic location, it would be extremely interesting to hear how far it reaches over the top of the world into the northern part of North America. The 252KHz frequency is shared with a station in North Africa that may hinder reception for some Europeans, but those with long memories in north-west Europe will find it fairly empty as it has been vacated in that region by the Irish transmitter which used to use it.

So if you have a receiver capable of catching long wave and you think you might be in range, give it a listen. Closer to where this article is being written, long wave stations are being turned off.

Harris & Ewing, photographer, Public domain.

Vintage Crystal Radio Draws The Waves

August 7, 2024 by 10 Comments

The classic crystal radio was an oatmeal box with some wire and a few parts. [Michael Simpson] has something very different. He found an assembled Philmore “selective” radio kit. The simple kit had a coil, a germanium diode, and a crystal earphone.

We were sad when [Michael] accidentally burned a part of the radio’s coil. But–well–in the end, it all worked out. We’ll just say that and let you watch for yourself. The radio is simplicity itself, built on a wooden substrate with a very basic coil and capacitor tuned circuit. Continue reading “Vintage Crystal Radio Draws The Waves” →

Radio Apocalypse: HFGCS, The Backup Plan For Doomsday

August 5, 2024 by 15 Comments

To the extent that you have an opinion on something like high-frequency (HF) radio, you probably associate it with amateur radio operators, hunched over their gear late at night as they try to make contact with a random stranger across the globe to talk about the fact that they’re both doing the same thing at the same time. In a world where you can reach out to almost anyone else in an instant using flashy apps on the Internet, HF radio’s reputation as somewhat old and fuddy is well-earned.

Like the general population, modern militaries have largely switched to digital networks and satellite links, using them to coordinate and command their strategic forces on a global level. But while military nets are designed to be resilient to attack, there’s only so much damage they can absorb before becoming degraded to the point of uselessness. A backup plan makes good military sense, and the properties of radio waves between 3 MHz and 30 MHz, especially the ability to bounce off the ionosphere, make HF radio a perfect fit.

The United States Strategic Forces Command, essentially the people who “push the button” that starts a Very Bad Day™, built their backup plan around the unique properties of HF radio. Its current incarnation is called the High-Frequency Global Communications System, or HFGCS. As the hams like to say, “When all else fails, there’s radio,” and HFGCS takes advantage of that to make sure the end of the world can be conducted in an orderly fashion.

Continue reading “Radio Apocalypse: HFGCS, The Backup Plan For Doomsday” →

You’ve Got The Portable Radio, Now What About The Antenna?

July 28, 2024 by 10 Comments

There’s an old saying in the amateur radio community that when it comes to antennas all you need is a piece of wet string. This may be a little fanciful, but it’s certainly true that an effective antenna can be made with surprisingly little in the way of conductor. It’s something [Evan Pratten VZ3ZZA] demonstrates amply with a description of the antenna he took camping in a Canadian provincial park.

Most of us would try some form of dipole on our adventures, but the antenna he’s using caught our eye as it’s described as an end-fed half-wave, but it has both a half-wave and quarter-wave element. Made from speaker cable or in this case thin mains cable for lamps, it’s obviously far from a perfect match and requires an ATU, but it generates an impressive array of FT4 contacts on a pretty meagre power level. We particularly like his in-plain-sight test run in the parking lot of a supermarket.

We frequently talk about the diversity of pursuits in amateur radio aside from that of the chequebook ham, and this project shows one of those. The world of QRP, operating at extreme low power, is not expensive to enter and can be extremely rewarding.

Are Hackers The Future Of Amateur Radio?

July 18, 2024 by 120 Comments

If amateur radio has a problem, it’s that shaking off an image of being the exclusive preserve of old men with shiny radios talking about old times remains a challenge. Especially, considering that so many amateurs are old men who like to talk a lot about old times. It’s difficult to attract new radio amateurs in the age of the Internet, so some in the hobby are trying new avenues. [Dan, KB6NU] went to the recent HOPE conference to evangelise amateur radio, and came away having had some success. We agree with him, hackers can be the future of amateur radio.

He’s put up the slides from his talk, and in them he goes through all the crossovers between the two communities from Arduinos to GNU Radio. We don’t need persuading, in fact we’d have added UHF and microwave RF circuitry and pushing the limits of the atmosphere with digital modes such as WSPR to the list as our personal favourites. It seems he found willing converts, and it’s certainly a theme we’ve featured before here at Hackaday. After all, unless it retains its interest, amateur radio could just die away.

Hackable Ham Radio Gives Up Its Mechanical Secrets

July 9, 2024 by 4 Comments

Reverse-engineered schematics are de rigeur around these parts, largely because they’re often the key to very cool hardware hacks. We don’t get to see many mechanical reverse-engineering efforts, though, which is a pity because electronic hacks often literally don’t stand on their own. That’s why these reverse-engineered mechanical diagrams of the Quansheng UV-K5 portable amateur radio transceiver really caught our eye.

Part of the reason for the dearth of mechanical diagrams for devices, even one as electrically and computationally hackable as the UV-K5, is that mechanical diagrams are a lot less abstract than a schematic or even firmware. Luckily, this fact didn’t daunt [mdlougheed] from putting a stripped-down UV-K5 under a camera for a series of images to gather the raw data needed by photogrammetry package RealityCapture. The point cloud was thoughtfully scaled to match the dimensions of the radio’s reverse-engineered PC board, so the two models can work together.

The results are pretty impressive, especially for a first effort, and should make electromechanical modifications to the radio all the easier to accomplish. Hats off to [mdlougheed] for the good work, and let the mechanical hacks begin.