Radio Hacks

1388 Articles

Red and gold bakelite Philco farm radio on a workbench

Hacking A Heavyweight Philco Radio

March 10, 2025 by 6 Comments

There’s something magical about the clunk of a heavy 1950s portable radio – the solid thunk of Bakelite, the warm hum of tubes glowing to life. This is exactly why [Ken’s Lab] took on the restoration of a Philco 52-664, a portable AC/DC radio originally sold for $45 in 1953 (a small fortune back then!). Despite its beat-up exterior and faulty guts, [Ken] methodically restored it to working condition. His video details every crackling capacitor and crusty resistor he replaced, and it’s pure catnip for any hacker with a soft spot for analog tech. Does the name Philco ring a bell? Lately, we did cover the restoration of a 1958 Philco Predicta television.

What sets this radio hack apart? To begin with, [Ken] kept the restoration authentic, repurposing original capacitor cans and using era-appropriate materials – right down to boiling out old electrolytics in his wife’s discarded cooking pot. But, he went further. Lacking the space for modern components, [Ken] fabbed up a custom mounting solution from stiff styrofoam, fibreboard, and all-purpose glue. He even re-routed the B-wiring with creative terminal hacks. It’s a masterclass in patience, precision, and resourcefulness.

If this tickles your inner tinkerer, don’t miss out on the full video. It’s like stepping into a time machine.

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Transceiver Reveals Unusual Components

March 8, 2025 by 22 Comments

[MSylvain59] likes to tear down old surplus, and in the video below, he takes apart a German transceiver known as a U-600M. From the outside, it looks like an unremarkable gray box, especially since it is supposed to work with a remote unit, so there’s very little on the outside other than connectors. Inside, though, there’s plenty to see and even a few surprises.

Inside is a neatly built RF circuit with obviously shielded compartments. In addition to a configurable power supply, the radio has modules that allow configuration to different frequencies. One of the odder components is a large metal cylinder marked MF450-1900. This appears to be a mechanical filter. There are also a number of unusual parts like dogbone capacitors and tons of trimmer capacitors.

The plug-in modules are especially dense and interesting. In particular, some of the boards are different from some of the others. It is an interesting design from a time predating broadband digital synthesis techniques.

While this transceiver is stuffed with parts, it probably performs quite well. However, transceivers can be simple. Even more so if you throw in an SDR chip.

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Get Into Meshtastic On The Cheap With This Tiny Node Kit

March 8, 2025 by 15 Comments

There’s been a lot of buzz about Meshtastic lately, and with good reason. The low-power LoRa-based network has a ton of interesting use cases, and as with any mesh network, the more nodes there are, the better it works for everyone. That’s why we’re excited by this super-affordable Meshtastic kit that lets you get a node on the air for about ten bucks.

The diminutive kit, which consists of a microcontroller and a LoRa module, has actually been available from the usual outlets for a while. But [concretedog] has been deep in the Meshtastic weeds lately, and decided to review its pros and cons. Setup starts with flashing Meshtastic to the XIAO ESP32-S3 microcontroller and connecting the included BLE antenna. After that, the Wio-SX1262 LoRa module is snapped to the microcontroller board via surface-mount connectors, and a separate LoRa antenna is connected. Flash the firmware (this combo is supported by the official web flasher), and you’re good to go.

What do you do with your new node? That’s largely up to you, of course. Most Meshtastic users seem content to send encrypted text messages back and forth, but as our own [Jonathan Bennett] notes, a Meshtastic network could be extremely useful for emergency preparedness. Build a few of these nodes, slap them in a 3D printed box, distribute them to willing neighbors, and suddenly you’ve got a way to keep connected in an emergency, no license required.

Dismanteled Hallicrafters radio on workbench

Shortwave Resurrection: A Sticky Switch Fix On A Hallicrafters

March 4, 2025 by 10 Comments

Shortwave radio has a charm all its own: part history, part mystery, and a whole lot of tech nostalgia. The Hallicrafters S-53A is a prime example of mid-century engineering, but when you get your hands on one, chances are it won’t be in mint condition. Which was exactly the case for this restoration project by [Ken’s Lab], where the biggest challenge wasn’t fried capacitors or burned-out tubes, but a stubborn band selector switch that refused to budge.

What made it come to this point? The answer is: time, oxidation, and old-school metal tolerances. Instead of forcing it (and risking a very bad day), [Ken]’s repair involved careful disassembly, a strategic application of lubricant, and a bit of patience. As the switch started to free up, another pleasant surprise emerged: all the tubes were original Hallicrafters stock. A rare find, and a solid reason to get this radio working without unnecessary modifications. Because some day, owning a shortwave radio could be a good decision.

Once powered up, the receiver sprang to life, picking up shortwave stations loud and clear. Hallicrafters’ legendary durability proved itself once before, in this fix that we covered last year. It’s a reminder that sometimes, the best repairs aren’t about drastic changes, but small, well-placed fixes.

What golden oldie did you manage to fix up?

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It’s SSB, But Maybe Not Quite As You Know It

March 3, 2025 by 17 Comments

Single Sideband, or SSB, has been the predominant amateur radio voice mode for many decades now. It has bee traditionally generated by analogue means, generating a double sideband and filtering away the unwanted side, or generating 90 degree phase shifted quadrature signals and mixing them. More recent software-defined radios have taken this into the CPU, but here’s [Georg DG6RS] with another method. It uses SDR techniques and a combination of AM and FM to achieve polar modulation and generate SSB. He’s provided a fascinating in-depth technical explanation to help understand how it works.

The hardware is relatively straightforward; an SI5351 clock generator provides the reference for an ADF4351 PLL and VCO, which in turn feeds a PE4302 digital attenuator. It’s all driven from an STM32F103 microcontroller which handles the signal processing. Internally this means conventionally creating I and Q streams from the incoming audio, then an algorithm to generate the phase and amplitude for polar modulation. These are fed to the PLL and attenuator in turn for FM and AM modulation, and the result is SSB. It’s only suitable for narrow bandwidths, but it’s a novel and surprisingly simple deign.

We like being presented with new (to us at least) techniques, as it never pays to stand still. Meanwhile for more conventional designs, we’ve got you covered.

A Ten Band SDR Transceiver For Homebrewers

February 26, 2025 by 9 Comments

Making a multi-band amateur radio transceiver has always been a somewhat challenging project, and making one that also supported different modes would for many years have been of almost impossible complexity best reserved for expensive commercial projects. [Bob W7PUA] has tackled both in the form of a portable 10-band multi-mode unit, and we can honestly say he’s done a very good job indeed.

As you might expect in 2025 it’s a software defined radio (SDR), but to show how powerful the silicon available today is, it’s all implemented on a microcontroller. There’s a Teensy 4 with an audio codec board that does all the signal processing heavy lifting, and an RF board that takes care of the I/Q mixing and the analogue stuff.

Band switching is handled using a technique from the past; interchangeable plug-in coil and filter units, that do an effective job. The result is a modestly-powered but extremely portable rig that doesn’t look to have broken the bank, and since the write-up goes into detail on the software side we hope it might inform other SDR projects too. We might have gone for old-school embossed Dymo labels on that brushed aluminium case just for retro appeal, but we can’t fault it.

It’s not the first time we’ve looked at a small multi-band SDR here, but we think this one ups the game somewhat.

Thanks [Pete] for the tip!

Retrotectacular: Ham Radio As It Was

February 21, 2025 by 22 Comments

We hear a lot about how ham radio isn’t what it used to be. But what was it like? Well, the ARRL’s film “The Ham’s Wide World” shows a snapshot of the radio hobby in the 1960s, which you can watch below. The narrator is no other than the famous ham [Arthur Godfrey] and also features fellow ham and U.S. Senator [Barry Goldwater]. But the real stars of the show are all the vintage gear: Heathkit, Swan, and a very oddly placed Drake.

The story starts with a QSO between a Mexican grocer and a U.S. teenager. But it quickly turns to a Field Day event. Since the film is from the ARRL, the terminology and explanations make sense. You’ll hear real Morse code and accurate ham lingo.

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