Inexpensive Ham Radio Gets Upgrades Thanks To A Trojan

July 6, 2023 by Dan Maloney 21 Comments

Love them or hate them, the crop of cheap hand-held amateur radio transceivers is here to stay. They’re generally horrible radios, often smearing spurious emissions across the spectrum, but they’re cheap enough to throw in a glove box for emergencies, and they invite experimentation — for instance, modifying the firmware to add functionality the OEM didn’t think to offer.

The new hotness in this class of radios is the Quansheng UV-K5, a two-band transceiver you can pick up for about $40, and we suspect it’ll get hotter still with this firmware trojan by [Piotr (SQ9P)]. We’ve already seen a firmware hack for these radios, one that aimed at unlocking the full frequency range of the RF chip at the heart of the radio. Honestly, we’re not huge fans of these mods, which potentially interfere with other allocations across multiple bands. But [Piotr]’s hacks seem a bit more innocuous, focusing mainly on modifying the radio’s display and adding useful features, such as a calibrated received signal strength bar graph and a numerical RSSI display. The really neat new feature, though, is the spectrum display, which shows activity across a 2-MHz slice of spectrum centered on the currently set frequency. And just because he could, [Piotr] put in a game of Pong.

[Piotr]’s description of the mod as a trojan seems apt since his new programs run in parallel to the OEM firmware by wrapping its vector table. We’d imagine other mods are possible, and we’re keen to see what people come up with for these hackable little units. Just make sure you’re staying within the law, especially in the United States — the FCC does not play games (third item).

Spy Radio Setup Gets A Tiny Power Supply For Field Operations

June 29, 2023 by Dan Maloney 14 Comments

[Helge Fyske (LA6NCA)] may not be an actual spy — then again, he may be; if he’s good at it, we wouldn’t know — but he has built a couple of neat vacuum tube spy radios in the past. And there’s no better test for such equipment than to haul it out into the field and try to make some contacts. But how do you power such things away from the bench?

To answer that question, skip ahead to the 3:18 mark of the video below, where [Helge] shows off his whole retro rig, including the compact 250-volt power supply he built for his two-tube 80-m Altoids tin spy transceiver. In the shack, [Helge] powers it with a bench power supply of his own design to provide the high anode voltage needed for the tubes, as well as 12 volts for their heaters. Portable operations require a more compact solution, preferably one that can be run off a battery small enough to pack in.

By building his power supply in a tin, [Helge] keeps to his compact build philosophy. But the circuit is all solid state, which is an interesting departure for him. The switch-mode supply uses a 4047 astable multivibrator chip as a 50-kHz oscillator, which switches back and forth between a pair of MOSFETs to drive a transformer. This steps up the 12-volt input to 280 volts AC, which is then rectified, filtered, and regulated to 250 volts DC.

To round out his spy rig, [Helge] also designed a tiny Morse key, which appears to be 3D printed and fits in its own tin, and a compact dipole antenna. Despite picking what appears to be a challenging location — the bottom of a steep-sided fjord — [Helge] was easily able to make contacts over a distance of 400 km. His noise floor was remarkably low, a testament to the solid design of his power supply. Including the sealed lead acid battery, the whole kit is compact and efficient, and it’s a nice example of what vacuum tubes and solid state can accomplish together.

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Hackaday Links: June 25, 2023

June 25, 2023 by Dan Maloney 15 Comments

Is it really a dystopian future if the robots are radio-controlled? That’s what came to mind reading this article on a police robot out of Singapore, complete with a breathless headline invoking Black Mirror, which is now apparently the standard by which all dystopias are to be judged. Granted, the episode with the robo-dogs was pretty terrifying, but it seems like the Singapore Police Force has a way to go before getting to that level. The bot, which has been fielded at Changi Airport after extensive testing and seems to be completely remote-controlled, is little more than a beefy telepresence robot. At 5.5 feet (1.7 meters) tall, the bot isn’t terribly imposing, although it apparently has a mast that can be jacked up another couple of feet, plus there are lights, sirens, and speakers that can get the message across. Plus cameras, of course; there are always cameras. The idea is to provide extra eyes to supplement foot patrols, plus the potential to cordon off an incident until meatspace officers arrive. The buzzword game here is weak, though; there’s no mention of AI or machine learning at all. We have a feeling that when the robots finally rise up, ones like this will be left serving the drinks.

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Ham Almost Cooks ‘Dog

June 14, 2023 by Jenny List 34 Comments

For those of us licensed in other countries it comes as something of a surprise to find that American radio amateurs now have to run RF exposure calculations as part of their licence requirements. [Ham Radio Crash Course] as approached this in a unique fashion, by running around 800 watts of 6-metre power into a vertical antenna festooned with hotdogs. That’s right, this ham is trying to cook some ‘dawgs! Is his station producing dangerous levels of power that might cook passers-by?

Of course, aside from a barely-warmed line along where the ‘dogs were attached to the antenna there’s no heating to be found. But we think he’s trying to make the point in the video below the break about the relative pointlessness of applying RF field limits which are definitely relevant at much higher frequencies, to hams at low frequencies.

It leaves us curious as to how that 800 watts could be efficiently transferred into the sausages and really cook them. Strapping them to a vertical is we think the equivalent of strapping anything resistive to a conductor, they do not form a significant enough part of the circuit. We think that even six metres could cook a sausage if it could be efficiently coupled into it, so we’d suggest putting a grounded sausage up the middle of a close-wound helix.

If you have any thoughts on the RF exposure calculations, or on the best way to cook a ‘dog with 6m, we’d love to hear the, in the comments. Meanwhile, this isn’t the first piece of ‘dog-based shenanigans we’ve brought you.

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Passionate Hams Make Their Mark On The Hack Chat

June 12, 2023 by Tom Nardi 63 Comments

Let’s be honest — there are some not very pleasant stereotypes associated with amateur radio, at least if you ask outsiders. Hams are often thought of as being in two camps: old guys who can’t figure out modern technology or conspiracy theorists who think their knowledge of radio will give them an edge after the world becomes a post-apocalyptic hellscape. We’ll leave it to you to decide which is the worse brush to be painted with.

As is often the case, the best way to fight such ignorance is with education and outreach. Events like our weekly Hack Chat are a perfect platform for that, as it allows the curious to ask questions and get answers directly from subject matter experts. This is precisely why we invited Mark Hughes and Beau Ambur to helm last week’s Chat. The fact that they’re both relatively recent licensees makes them uniquely qualified to shed some light on what it’s like to become part of the ham radio community in the 21st century. As an added bonus, they’re both sharp and articulate technologists — about as far as you can get from the mental image of the doddering old granddad who prefers the simplicity of the Morse key to those newfangled smarty-phones.

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Listening To The ISS On The Cheap

June 10, 2023 by Dan Maloney 36 Comments

Like any hobby, amateur radio has no upper bounds on what you can spend getting geared up. Shacks worth tens of thousands of dollars are easy to come by, and we’ll venture a guess that there are hams out there pushing six figures with their investment in equipment. But hands down, the most expensive amateur radio station ever has to be the one aboard the International Space Station.

So what do you need to talk to a $100 billion space station? As it turns out, about $60 worth of stuff will do, as [saveitforparts] shows us in the video below. The cross-band repeater on the ISS transmits in the 70-cm ham band, meaning all that’s needed to listen in on the proceedings is a simple “handy talkie” transceiver like the $25-ish Baofeng shown. Tuning it to the 437.800-MHz downlink frequency with even a simple whip antenna should get you some reception when the ISS passes over.

In our experience, the stock Baofeng antenna isn’t up to the job, so something better like the Nagoya shown in the video is needed. Better still is a three-element Yagi tuned down slightly with the help of a NanoVNA; coupled with data on when the ISS will be within line-of-sight, picking up the near-constant stream of retransmissions from the station as Earth-based hams work it should be a snap — even though [saveitforparts] only listened to the downlink frequency here, for just a bit more of an investment it’s also possible for licensed hams to uplink to the ISS on 145.900 MHz.

For those who want a slightly higher level of difficulty, [saveitforparts] also has some tips on automating tracking with an old motorized mount for CCTV cameras. Pitchfork notwithstanding, it’s not the best antenna tracker, but it has promise, and we’re eager to see how it pans out — sorry. But in general, the barrier to entry for getting into space communications is so low that you could easily make this a weekend project. We’ve been discussing this and other projects on the new #ham-shack channel over on the Hackaday Discord. You should pop over there and check it out — we’d be happy to see you there.

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Hackaday Links: June 4, 2023

June 4, 2023 by Dan Maloney 9 Comments

A report released this week suggests that 50 flights into its five-flight schedule, the Mars helicopter might be starting to show its age. The report details a protracted communications outage Ingenuity’s flight controllers struggled with for six sols after flight 49 back in April. At first attributed to a “communications shadow” caused by the helicopter’s robotic buddy, Perseverance, moving behind a rocky outcrop and denying line of sight, things got a little dicey once the rover repositioned and there was still no joy. Since the helicopter has now graduated from “technology demonstration” to a full-fledged member of the team tasked with scouting locations for the rover while respecting the no-fly zone around it, it was essential to get it flying again. Several attempts to upload a flight plan failed with nothing but an acknowledgment signal from the helicopter, but a final attempt got the program uploaded and flight 50 was a complete if belated success. So that’s good, but the worrying news is that since Sol 685, the helicopter has been switching in and out of nighttime survival mode. What that portends is unclear, but no matter how amazing the engineering is, there’s only so much that can be asked on Ingenuity before something finally gives.

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