Radio Apocalypse: Clearing The Air With SCATANA

For the most part, the Radio Apocalypse series has focused on the radio systems developed during the early days of the atomic age to ensure that Armageddon would be as orderly an affair as possible. From systems that provided backup methods to ensure that launch orders would reach the bombers and missiles, to providing hardened communications systems to allow survivors to coordinate relief and start rebuilding civilization from the ashes, a lot of effort went into getting messages sent.

Strangely, though, the architects of the end of the world put just as much thought into making sure messages didn’t get sent. The electronic village of mid-century America was abuzz with signals, any of which could be abused by enemy forces. CONELRAD, which aimed to prevent enemy bombers from using civilian broadcast signals as navigation aids, is a perfect example of this. But the growth of civil aviation through the period presented a unique challenge, particularly with the radio navigation system built specifically to make air travel as safe and reliable as possible.

Balancing the needs of civil aviation against the possibility that the very infrastructure making it possible could be used as a weapon against the U.S. homeland is the purpose of a plan called Security Control of Air Traffic and Air Navigation Aids, or SCATANA. It’s a plan that cuts across jurisdictions, bringing military, aviation, and communications authorities into the loop for decisions regarding when and how to shut down the entire air traffic system, to sort friend from foe, to give the military room to work, and, perhaps most importantly, to keep enemy aircraft as blind as possible. Continue reading “Radio Apocalypse: Clearing The Air With SCATANA”

ESP32-Powered Clock Brings Aviation Style To Your Desk

There’s something cool about the visual design language used in the aviation world. You probably don’t get much exposure to it if you’re not regularly flying a plane, but there are other ways you can bring it into your life. A great example would be building an aviation-themed clock, like this stylish timepiece from [oliverb.]

The electronic heart of the build is an ESP32. This wireless-capable microcontroller is a popular choice for clock builds these days. This is because it can contact network time servers out of the box, which allows you to build an incredibly capable and accurate clock without any additional parts. No real-time-clock needed—just have the ESP32 buzz the Internet for an accurate update on the regular!

As for the display itself, three gauges show hours, minutes, and seconds on aviation-like gauges. They’re 3D-printed, which means you can build them from scratch. That’s a touch easier than having to go out and source actual surplus aviation hardware. Each gauge is driven by a NEMA17 stepper motor. There’s also an ATMEGA328 on hand to drive a 7-segment gauge on the seconds display, and a PIR sensor which shuts the clock down when nobody is around to view it.

It’s a tidy build, and one with a compelling aesthetic at that. We’ve seen some similar builds before using real aviation gauges, too. Video after the break.

Continue reading “ESP32-Powered Clock Brings Aviation Style To Your Desk”

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Hackaday Links: January 12, 2025

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.

Continue reading “Hackaday Links: January 12, 2025”

All-Band Receiver Lets You Listen To All The Radio At Once

There are many ways to build a radio receiver, but most have a few things in common, such as oscillators, tuned circuits, detectors, mixers, and amplifiers. Put those together in the right order and you’ve got a receiver ready to tune in whatever you want to listen to. But if you don’t really care about tuning and want to hear everything all at once, that greatly simplifies the job and leaves you with something like this homebrew all-band receiver.

Granted, dispensing with everything but a detector and an audio amplifier will seriously limit any receiver’s capabilities. But that wasn’t really a design concern for [Ido Roseman], who was in search of a simple and unobtrusive way to monitor air traffic control conversations while flying. True, there are commercially available radios that tune the aviation bands, and there are plenty of software-defined radio (SDR) options, but air travel authorities and fellow travelers alike may take a dim view of an antenna sticking out of a pocket.

So [Ido] did a little digging and found a dead-simple circuit that can receive signals from the medium-wave bands up into the VHF range without regard for modulation. The basic circuit is a Schottky diode detector between an antenna and a high-gain audio amplifier driving high-impedance headphones; [Ido] built a variation that also has an LM386 amplifier stage to allow the use of regular earbuds, which along with a simple 3D-printed case aids in the receiver’s stealth.

With only a short piece of wire as an antenna, reception is limited to nearby powerful transmitters, but that makes it suitable for getting at least the pilot side of ATC conversations. It works surprisingly well — [Ido] included a few clips that are perfectly understandable, even if the receiver also captured things like cell phones chirping and what sounds like random sferics. It seems like a fun circuit to play with, although with our luck we’d probably not try to take it on a plane.

Tailwheel Trainer Go-Cart To Avoid Wrecked Planes

Taildraggers remain a popular configuration for small aircraft, but they come with a significant risk during ground handling: ground loops. If the tail gets too far off course, it can swing around completely, often damaging or destroying aircraft if a wing hits the ground. Avoiding ground loops requires good rudder and brake control, and there currently isn’t a good way to learn it without getting into an actual aircraft. [Trent Palmer] is a pilot and who has been thinking about this problem for a few years, so he built a 3-wheeled electric go-cart to help pilots train their ground handling.

The cart is controlled exactly like a taildragger, with a pair of rudder pedals connected to the single steerable via cables, and springs to add some response delay. Independent hydraulic brakes on each main wheel, operated by toe pedals, further simulate the control on many aircraft. The main wheel are controlled with a throttle lever, with a differential to allow them to rotate at different speeds. The cart is unforgiving, and requires constant corrections with the pedals to keep it going straight.[Trent] had few pilot and non-pilot friends try out the cart, and even the experienced tailwheel pilots got into ground loop. It might be bit too sensitive, but everyone agreed that mastering this cart would significantly improve ground handling skills in actual aircraft.

Repairing a damaged aircraft can cost several thousand dollar, so a cheap training tool like this could prove invaluable flight schools and even individual pilots. [Trent] doesn’t have big plans for commercialization, but we wouldn’t be surprised if it goes that way.

Taildraggers are especially popular as bush planes, with many tracing their heritage from the humble Piper J-3 Cub. We’ve seen some extreme extreme modern bush planes, like [Mike Patey]’s Scrappy and Draco builds. Continue reading “Tailwheel Trainer Go-Cart To Avoid Wrecked Planes”

Unlocking The Mystery Of An Aircraft ADI

If you’ve ever seen the cockpit of an airplane, you’ve probably noticed the round ball that shows your attitude, and if you are like us, you’ve wondered exactly how the Attitude Direction Indicator (ADI) works. Well, [msylvain59] is tearing one apart in the video below, so you can satisfy your curiosity in less than 30 minutes.

Like most things on an airplane, it is built solidly and compactly. With the lid open, it reminded us of a tiny CRT oscilloscope, except the CRT is really the ball display. It also has gears, which is something we don’t expect to see in a scope.

Continue reading “Unlocking The Mystery Of An Aircraft ADI”

Cockpit of a Hawker Siddeley Trident with the moving map display

A Live Map Display In A 1960s Airliner

We tend take GPS navigation for granted these days, so it’s easy to forget that it became only available in the last few decades. Aviation navigation used to be significantly more challenging, so how was the Hawker Siddeley Trident, a 1960s airliner, fitted with a live updating map display? In a fascinating dive into aviation history the British Airliner Collection has spun up an insightful article on the magic behind these moving map displays.

Without access to satellite navigation or advanced electronics, engineers had to get creative. Enter the Trident’s moving map display, a marvel of ingenuity that predated the GPS systems. Using a combination of Doppler radar and some clever mechanics, pilots could accurately determine their position without relying on any external signals.

The system makes use of four Doppler radar beams, arranged in what was known as the Janus array. This configuration corrected for errors caused by changes in altitude or wind drift, ensuring accurate ground speed readings. The movable antennas mounted under the cabin floor could adjust its orientation to maintain alignment with the actual direction of travel, calculating drift angle precisely. Combined with compass information and flight time from a known start point to to indicate the current position with a pointer on a rolled paper map. The system was well ahead of it’s time, and significantly easier to use and more accurate than the Decca radio navigation system in use at the time.

It’s mind boggling to see the solutions engineers came up with without much of the digital technology we take for granted today. Gyroscopes for inertial navigation, the cavity magnetron for radar and radial engines were all building blocks for modern aviation.

Thanks for the tip [poiuyt]!