amateur radio

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Hackaday Links: January 12, 2025

January 12, 2025 by 5 Comments

The big news story of the week of course has been the wildfires in California, which as of Saturday have burned over 30,000 acres, destroyed 12,000 structures, caused 150,000 people to evacuate, and killed eleven people. Actually, calling them wildfires underplays the situation a bit because there are places where they’ve clearly become firestorms, burning intensely enough to create their own winds, consuming everything in their path in a horrific positive feedback loop. We’ve even seen fire tornados caught on video. We’ve got quite a few connections to the affected area, both personally and professionally, not least of which are all our Supplyframe colleagues in Pasadena, who are under immediate threat from the Eaton fire. We don’t know many details yet, but we’ve heard that some have lost homes. We’ve also got friends at the Jet Propulsion Labs, which closed a few days ago to all but emergency personnel. The fire doesn’t seem to have made it down the mountain yet, but it’s very close as of Saturday noon.

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Pi Pico Makes SSTV Reception A Snap

January 4, 2025 by 9 Comments

There’s a paradox in amateur radio: after all the time and effort spent getting a license and all the expense of getting some gear together, some new hams suddenly find that they don’t have a lot to talk about when they get in front of the mic. While that can be awkward, it’s not a deal-breaker by any means, especially when this Pi Pico SSTV decoder makes it cheap and easy to get into slow-scan television.

There’s not much to [Jon Dawson]’s SSTV decoder. Audio from a single-sideband receiver goes through a biasing network and into the Pico’s A/D input. The decoder can handle both Martin and Scottie SSTV protocols, with results displayed on a TFT LCD screen. The magic is in the software, of course, and [Jon] provides a good explanation of the algorithms he used, as well as some of the challenges he faced, such as reliably detecting which protocol is being used. He also implemented correction for “slant,” which occurs when the transmitter sample rate drifts relative to the receiver. Fixing that requires measuring the time it took to transmit each line and adjusting the timing of the decoder to match. The results are dramatic, and it clears up one of the main sources of SSTV artifacts.

We think this is a great build, and simple enough that anyone can try it. The best part is that since it’s receive-only, it doesn’t require a license, although [Jon] says he’s working on an encoder and transmitter too. We’re looking forward to that, but in the meantime, you might just be able to use this to capture some space memes.

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Lowering Your Noise Floor, The Easy Way

December 31, 2024 by 35 Comments

If there’s anything more annoying to an amateur radio operator than noise, we’re not sure what it could be. We’re talking about radio frequency noise, of course, the random broadband emissions that threaten to make it almost impossible to work the bands and pick out weak signals. This man-made interference is known as “QRM” in ham parlance, and it has become almost intolerable of late, as poorly engineered switch-mode power supplies have become more common.

But hams love a technical challenge, so when a nasty case of QRM raised its ugly head, [Kevin Loughlin (KB9RLW)] fought back. With an unacceptable noise floor of S8, he went on a search for the guilty party, and in the simplest way possible — he started flipping circuit breakers. Sure, he could have pulled out something fancier like a TinySA spectrum analyzer, but with his HF rig on and blasting white noise, it was far easier to just work through the circuits one by one to narrow the source down. His noise problem went away with the living room breaker, which led to pulling plugs one by one until he located the culprit: a Roomba vacuum’s charging station.

Yes, this is a simple trick, but one that’s worth remembering as at least a first pass when QRM problems creep up. It probably won’t help if the source is coming from a neighbor’s house, but it’s a least worth a shot before going to more involved steps. As for remediation, [Kevin] opts to just unplug the Roomba when he wants to work the bands, but if you find that something like an Ethernet cable is causing your QRM issue, you might have to try different measures.

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Wago Terminals Make This Ham Radio Dipole Light And Packable

December 15, 2024 by 13 Comments

For the amateur radio operator with that on-the-go lifestyle, nothing is more important than having your gear as light and packable as possible. If you’re lugging even a modest setup out into the woods, every ounce counts, which is why we love projects like this packable dipole antenna feedpoint.

At its simplest, a dipole antenna is just two pieces of wire cut to a specific, frequency-dependent length connected to a feedline. In practical terms, though, complications arise, such as keeping common-mode currents off the feedline and providing sturdy mechanical support for the antenna to suspend it safely. [Ham Radio Dude]’s design handles both those requirements while staying as small and packable as possible. The design starts with a bifilar 1:1 current balun, which is wound on an FT82-43 ferrite toroid with 22 AWG magnet wire. One side of the balun is connected to a BNC connector while the other is connected to a pair of Wago splice connectors that are glued together. A loop of paracord for mechanical strain relief is added, and the whole thing gets covered in heat-shrink tubing. The antenna is deployed by attaching a feedline to the BNC, clipping quarter-wave wires into the Wago terminals, and hoisting the whole thing aloft. Full build details are in the video below.

People will no doubt be quick to point out that these Wago terminals are rated for a minimum of 18 AWG wire, making them inappropriate for use with fine magnet wire. True enough, but [Dude] was able to get continuity through the Wagos, so the minimum gauge is probably more of an electrical code thing. Still, you’ll want to be careful that the connections stay solid, and it might pay to look at alternatives to the Wago brand, too. Continue reading “Wago Terminals Make This Ham Radio Dipole Light And Packable” →

Amateur Radio Operators Detect Signals From Voyager 1

December 11, 2024 by 40 Comments

At the time of its construction in the 1950s, the Dwingeloo Radio Observatory was the largest rotatable telescope in the world with a dish diameter of 25 meters. It was quickly overtaken in the rankings but was used by astronomers for decades until it slowly fell into disuse in the early 2000s. After a restoration project the telescope is now a national heritage site in the Netherlands where it is also available for use by radio amateurs. Recently this group was able to receive signals from Voyager 1.

Famously, Voyager 1 is the furthest manmade object from Earth, having been launched on a trajectory out of the solar system in 1977. As a result of distance and age, the signals it sends out are incredibly faint. The team first had to mount a new antenna to the dish, which was not originally designed for signals in this frequency which added to the challenge. They then needed to use orbital predictions of the spacecraft in order to target the telescope and also make the correct adjustments to the received signal given that there is significant Doppler shift now as well. But with that all out of the way, the team was successfully able to receive the Voyager 1 signal on this telescope.

Only a few telescopes in the world have ever been able to accomplish this feat, making it all the more impressive. Normally Voyager 1 is received using the Deep Space Network, a fleet of much larger dishes stationed around the world and designed for these frequencies. But this team is used to taking on unique challenges. They also decoded the first ham radio station on the moon and made a radar image of the moon using LoRa.

Dwingeloo telescope receives signals from Voyager 1

Turning A Quansheng Handheld Into A Neat Desktop Transceiver

October 28, 2024 by 18 Comments

The Quansheng UV-K5 is a popular handheld radio. It’s useful out of the box, but also cherished for its modification potential. [OM0ET] purchased one of these capable VHF/UHF radios, but got to hacking—as he wanted to use it as a desktop radio instead!

This might just sound like a simple reshell, but there was actually a bit of extra work involved. Most notably, the Quansheng is designed to be tuned solely by using the keypad. For desktop use, though, that’s actually kind of a pain. Thus, to make life easier, [OM0ET] decided to whip up a little encoder control to handle tuning and other control tasks using an ESP32. This was achieved with help from one [OM0WT] and files for that are on Github. Other tasks involved finding a way to make the keypad work in a new housing, and how to adapt things like the audio and data module and the speaker to their new homes.

Despite the original handheld being much smaller than the case used here, you’d be surprised how tight everything fits in the case. Still, the finished result looks great. We’ve seen some other adaptable and upgradable ham radio gear before, too. Sometimes custom is the way to go! Video after the break.

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Hackaday Links: October 20, 2024

October 20, 2024 by 44 Comments

When all else fails, there’s radio. Hurricane Helene’s path of destruction through Appalachia stripped away every shred of modern infrastructure in some areas, leaving millions of residents with no ability to reach out to family members or call for assistance, and depriving them of any news from the outside world. But radio seems to be carrying the day, with amateur radio operators and commercial broadcasters alike stepping up to the challenge.

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