Hackaday Links: February 23, 2020

February 23, 2020 by Dan Maloney 19 Comments

If you think your data rates suck, take pity on New Horizons. The space probe, which gave us lovely pictures of the hapless one-time planet Pluto after its 2015 flyby, continued to plunge and explore other, smaller objects in the Kuiper belt. In January of 2019, New Horizons zipped by Kuiper belt object Arrokoth and buffered its findings on the spacecraft’s solid-state data recorders. The probe has been dribbling data back to Earth ever since at the rate of 1 to 2 kilobits per second, and now we have enough of that data to piece together a story of how planets may have formed in the early solar system. The planetary science is fascinating, but for our money, getting a probe to narrowly miss a 35-kilometer long object at a range of 6.5 billion km all while traveling at 51,500 km/h is pretty impressive. And if as expected it takes until September to retrieve all the data from the event at a speed worse than dialup rates, it’ll be worth the wait.

Speaking of space, if you’re at all interested in big data, you might want to consider putting your skills to work in the search for extraterrestrial intelligence. The Berkeley SETI Research Center has been feeding data from the Green Bank Telescope and their Automated Planet Finder into the public archive of Breakthrough Listen, a 10-year, $100 million initiative to scan the million closest stars in our galaxy as well as the 100 nearest galaxies for signs of intelligent life. They’re asking for help to analyze the torrents of data they’re accumulating, specifically by developing software and algorithms to process the data. They’ve set up a site to walk you through the basics and get you started. If you’re handy with Python and have an interest in astronomy, you should check it out.

Staying with the space theme, what’s the best way to get kids interested in space and electronics? Why, by launching a satellite designed to meme its way across the heavens, of course. The Mission for Education and Multimedia Engagement satellite, or MEMESat-1, is being planned for a February 2021 launch. The 1U cubesat will serve as an amateur radio repeater and slow-scan TV (SSTV) beacon that will beam down memes donated to the project and stored on radiation-hardened flash storage. In all seriousness, this seems like a great way to engage the generation that elevated the meme to a modern art form in a STEM project they might otherwise show little interest in.

It looks as though Linux might be getting a big boost as the government of South Korea announced that they’re switching 3.3 million PCs from Windows to Linux. It’s tempting to blame Microsoft’s recent dropping of Windows 7 support for the defenestration, but this sounds like a plan that’s been in the works for a while. No official word on which distro will be selected for the 780 billion won ($655 million) effort, which is said to be driven by ballooning software license costs and a desire to get out from under Microsoft’s thumb.

And finally, in perhaps the ickiest auction ever held, the “Davos Collection” headed to the auction block this week in New York. The items offered were all collected from the 2018 World Economic Forum in Davos, Switzerland, where the world’s elites gather to determine the fate of the 99.999%. Every item in the collection, ranging from utensils and glassware used at the many lavish meals to “sanitary items” disposed of by the billionaires, and even hair and fluid samples swabbed from restrooms, potentially holds a genetic treasure trove in the form of the DNA it takes to be in the elite. Or at least that’s the theory. There’s a whole “Boys from Brazil” vibe here that we find disquieting, and we flatly refuse to see how an auction where a used paper cup is offered for $8,000 went, but if you’d like to virtually browse through the ostensibly valuable trash of oligarchs, check out the auction catalog.

Stout Homebrew Radio Pumps Out 200W Of AM Goodness

February 20, 2020 by Lewin Day 7 Comments

In this day and age, with cheap online shopping, software defined radio and bargain-basement Baofengs from China, the upstart radio ham is spoilt for choice. Of course, there’s nothing quite like the charm of keying up your own homebrewed rig, cooked up in the garage from scratch. [Paul], aka [VK3HN], knows just how it feels, and put together an epic 200 watt Class D AM rig to blast his signal on the airwaves.

An example of an Arduino used in one of [Paul]’s builds.

It’s a build following on from the work of another radio ham, [Laurie], aka [VK3SJ]. Younger hackers will note the Arduino Nano at the heart of the project, running the VFO and handling all the relevant transmit/receive switching. We can only imagine how welcome modern microcontrollers must have been to old hands at amateur radio, making synthesizing all manner of wild frequencies a cinch.

The amount of effort that has gone into the build is huge. There are handwound coils for the PWM low-pass filter, and the PCB is home-etched in ferric chloride, doing things the old-school way. There’s also a healthy pile of dead components that sacrificed their lives in the development of this build. Perhaps our favorite part is the general aesthetic – we can’t get over the combination of hand-drawn copper traces and off-the-shelf Arduinos.

Many components perished in the development of this powerful rig.

It’s a build that far exceeds the Australian legal limits, so it only gets keyed up to 120W in real use. This has the benefit of keeping the radio operating far in the safety zone for its components, helping keep things cool and stable. We’re sure [Paul] will be getting some great contacts on this rig. If you’re suffering from low power yourself, consider an amplifer build. Video after the break.

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Name That Unknown RF Signal With A Little FFT Magic

February 11, 2020 by Dan Maloney 27 Comments

Time was once that the amateur radio bands were an aurally predictable place. Spinning the dial up and down the bands, one heard familiar sounds – the staccato of Morse, the [Donald Duck] of sideband voice transmissions, and the occasional flute-like warble of radioteletype signals. Now, the ham bands are full of exotic signals encoding all manner of digital signals, each one with a unique sound and unique demodulation needs. What’s a ham to do?

Help is on the way. [José Carlos Rueda] has made progress toward automatically classifying unknown signals by modifying a Shazam-like app. Shazam is a popular smartphone app that listens to a few seconds of a song, creates an audio fingerprint of it, and searches a massive database of songs for a match. [Rueda] used a homebrew version of the app to search a SQL-lite database of audio fingerprints populated not with a playlist of popular music, but with samples from every known signal type in the Signal Identification Wiki. The database contains hashes for an FFT of each sample, which can be easily searched. With a five to ten second sample of a signal, captured either live over a microphone or from a recording, he is able to identify the signal automatically.

Whether it be the weird, dissonant wail of PSK-31 or the angry buzzing of PACTOR, the goings-on across the bands no longer have to remain a mystery. We really like the idea here, and wonder if it can be expanded upon to visually decode signals based on their waterfall signatures using TensorFlow. There are some waterfall examples in [Danie Conradie]’s excellent article on RF modulation that could get you started.

[via RTL-SDR.com]

Keeping Ham Radio Relevant Hack Chat

February 3, 2020 by Dan Maloney 69 Comments

Join us on Wednesday, February 5 at noon Pacific for the Keeping Ham Radio Relevant Hack Chat with Josh Nass!

It may not seem like it, but amateur radio is fighting a two-front war for its continued existence. On the spectrum side, hams face the constant threat that the precious scraps of spectrum that are still allocated to their use will be reclaimed and sold off to the highest bidder as new communication technologies are developed. On the demographic side, amateur radio is aging, with fewer and fewer young people interested in doing the work needed to get licensed, with fewer still having the means to get on the air.

Amateur radio has a long, rich history, but gone are the days when hams can claim their hobby is sacrosanct because it provides communications in an emergency. Resting on that particular laurel will not win the hobby new adherents or help it hold onto its spectrum allocations, so Josh Nass (KI6NAZ) is helping change the conversation. Josh is an engineer and radio amateur from Southern California who runs Ham Radio Crash Course, a YouTube channel dedicated to getting people up to speed on ham radio. Josh’s weekly livestreams and his video reviews of ham radio products and projects show a different side of the World’s Greatest Hobby, one that’s more active (through events like “Summits on the Air”) and focused on digital modes that are perhaps more interesting and accessible to new hams.

Join us on the Hack Chat as we discuss how to make ham radio matter in today’s world of pervasive technology. We’ll talk about the challenges facing amateur radio, the fun that’s still to be had on the air even when the bands are dead like they are now (spoiler alert: they’re not really), and what we can all do to keep ham radio relevant.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 5 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about. Continue reading “Keeping Ham Radio Relevant Hack Chat” →

Hiking Pole Turned Lightweight Yagi Antenna

January 9, 2020 by Tom Nardi 10 Comments

Among amateur radio enthusiasts, there’s a subset of users who climb mountainous areas to use their gear from elevated positions. Anyone looking to take part in what’s known as Summits on the Air (SOTA) will obviously want to keep their equipment as light and small as possible. For [Stuart Thomas], that meant a collapsible yagi antenna he could easily pack away.

But one day he wondered why he was carrying around a separate antenna boom when his aluminum hiking pole would make a perfectly good substitute. All he had to do was figure out a way to mount the elements to the pole in a way that could be easily assembled in the field. He initially tried to use the sort of insulated electrical clamps used to hold down conduit, but he found they weren’t quite what he was after.

[Stuart] eventually ended up designing and 3D printing his own element mounts that use an M3 bolt to tightly clamp onto the hiking pole, preventing them from twisting while still being very lightweight and easy to adjust. To further reduce the packed size of the antenna, he cut each element in half with a pipe cutter and flared the ends slightly so he could reassemble them on location with inserts.

Even if you aren’t the type of person who owns hiking poles, let alone climbs mountains for fun, there’s still plenty of interesting applications for a lightweight yagi antenna. We’ve seen custom yagis built out of carbon fiber before and of course cobbling one together out of PVC and tape measures is a classic hack, but we think the solution [Stuart] has come up with strikes a nice balance between the extremes.

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WWII Aircraft Radio Roars To Life: What It Takes To Restore A Piece Of History

December 12, 2019 by Gregory L. Charvat 59 Comments

I’ve been told all my life about old-timey Army/Navy surplus stores where you could buy buckets of FT-243 crystals, radio gear, gas masks, and even a Jeep boxed-up in a big wooden crate. Sadly this is no longer the case. Today surplus stores only have contemporary Chinese-made boots, camping gear, and flashlights. They are bitterly disappointing except for one surplus store that I found while on vacation in the Adirondacks: Patriot of Lake George.

There I found a unicorn of historical significance; an un-modified-since-WW2 surplus CBY-46104 receiver with dynamotor. The date of manufacture was early-war, February 1942. This thing was preserved as good as the day it was removed from its F4F Hellcat. No ham has ever laid a soldering iron or a drill bit to it. Could this unit have seen some action in the south Pacific? Imagine the stories it could tell!

My unconventional restoration of this radio followed strict rules so as to minimize the evidence of repair both inside and out yet make this radio perform again as though it came fresh off the assembly line. Let’s see how I did.

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Hacking Transmitters, 1920s Style

November 28, 2019 by Sharon Lin 9 Comments

The origin of the term “breadboard” comes from an amusing past when wooden bread boards were swiped from kitchens and used as a canvas for radio hobbyists to roll homemade capacitors, inductors, and switches. At a period when commercial electronic components were limited, anything within reach was fair game.

[Andy Flowers], call sign K0SM, recently recreated some early transmitters using the same resources and techniques from the 1920s for the Bruce Kelley 1929 QSO Party. The style of the transmitters are based on [Ralph Hartley]’s oscillator circuit built for Bell Telephone in 1915. Most of the components he uses are from the time period, and one of the tubes he uses is even one of four tubes from the first Transatlantic contact in 1923.

Apart from vacuum tubes (which could be purchased) and meters (which could be scrounged from automobiles) [Flowers] recreated his own ferrite plate and outlet condensers for tuning the antennas. The spiderweb coils may not be as common today, but can be found in older Crosley receivers and use less wire than comparable cylindrical coils.

A number of others features of the transmitters also evoke period nostalgia. The coupling to the antenna can be changed using movable glass rods, although without shielding there are quite a number of factors to account for. A vertical panel in the 1920s style also shows measurements from the filament, plate current, and antenna coupling.

While amature radio has become increasingly high-tech over the last few years, it’s always good to see dedicated individuals keeping the old ways alive; no matter what kind of technology they’re interested in.

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