Radio Hacks

1322 Articles

Speech To Morse Code, Courtesy Of Google

July 16, 2020 by 16 Comments

Google has been responsible for unleashing some pretty incredible hardware and software on the world, but they can only take partial credit for the voice to Morse code gadget that [WhiskeyTangoHotel] recently completed.

With the Google AIY Voice Bonnet, [WhiskeyTangoHotel] had everything he needed to pick up on human speech and turn that into text the Raspberry Pi can parse and act on. Usually this would get passed to some kind of virtual assistant software, but in this case, a Python script breaks the speech down into individual characters and looks up their Morse representations. All those “dits” and “dahs” are then sent to one of the Pi’s GPIO pins, to which a relay has been connected.

At this point, you’ve got an interesting little toy that can sit on your desk and turn your speech into audible Morse code as the relay clicks and clacks its way through the message. In fact, if you don’t have a ham radio license, this is probably where you should stop. But if you’ve done the appropriate paperwork to transmit over the air, the relay can be connected to a radio to actually transmit messages.

If you think giving Google access to the content of your Morse code messages is a step too far, you’ll just have to learn it yourself. It might not be necessary to get your amateur license anymore, but that doesn’t mean it’s not worth knowing.

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Exposing Computer Monitor Side-Channel Vulnerabilities With TempestSDR

July 15, 2020 by 12 Comments

Having been endlessly regaled with tales of side-channel attacks and remote exploits, most of us by now realize that almost every piece of gear leaks data like a sieve. Everything from routers to TVs to the power supplies and cooling fans of computers can be made to give up their secrets. It’s scary stuff, but it also sounds like a heck of a lot of fun, and with an SDR and a little software, you too can get in on the side-channel action.

Coming to us via software-defined radio buff [Tech Minds], the video below gives a quick tour of how to snoop in on what’s being displayed on a monitor for almost no effort or expense. The software that makes it possible is TempestSDR, which was designed specifically for the job. With nothing but an AirSpy Mini and a rubber duck antenna, [Tech Minds] was able to reconstruct a readable black and white image of his screen at a range of a few inches; a better antenna and some fiddling might improve that range to several meters. He also shares a trick for getting TempestSDR set up for all the popular SDRs, including SPRplay, HackRF, and RTL-SDR.

Learning what’s possible with side-channel attacks is the key to avoiding them, so hats off to [Tech Minds] for putting together this simple, easy-to-replicate demo. To learn even more, listen to what [Samy Kamkar] has to say about the subject, or check out where power supplies, cryptocurrency wallets, and mixed-signal microcontrollers are all vulnerable.

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High-End Ham Radio Gives Up Its Firmware Secrets

July 14, 2020 by 46 Comments

Amateur radio operators have always been at the top of their game when they’ve been hacking radios. A ham license gives you permission to open up a radio and modify it, or even to build a radio from scratch. True, as technology has advanced the opportunities for old school radio hacking have diminished, but that doesn’t mean that the new computerized radios aren’t vulnerable to the diligent ham’s tender ministrations.

A case in point: the Kenwood TH-D74A’s firmware has been dumped and partially decoded. A somewhat informal collaboration between [Hash (AG5OW)] and [Travis Goodspeed (KK4VCZ)], the process that started with [Hash]’s teardown of his radio, seen in the video below. The radio, a tri-band handy talkie with capabilities miles beyond even the most complex of the cheap imports and with a price tag to match, had a serial port and JTAG connector. A JTAGulator allowed him to probe some of the secrets, but a full exploration required spending $140 on a spare PCB for the radio and some deft work removing the BGA-packaged Flash ROM and dumping its image to disk.

[Travis] picked up the analysis from there. He found three programs within the image, including the radio’s firmware and a bunch of strings used in the radio’s UI, in both English and Japanese. The work is far from complete, but the foundation is there for further exploration and potential future firmware patches to give the radio a different feature set.

This is a great case study in reverse engineering, and it’s really worth a trip down the rabbit hole to learn more. If you’re looking for a more formal exploration of reverse engineering, you could do a lot worse than HackadayU’s “Reverse Engineering with Ghidra” course, which just wrapping up. Watch for the class videos soon. Continue reading “High-End Ham Radio Gives Up Its Firmware Secrets” →

NASA Making Big Upgrades To Their Big Dish DSS43

July 13, 2020 by 16 Comments

When it comes to antenna projects, we usually cover little ones here. From copper traces on a circuit board to hand-made units for ham radio. But every once in a while it’s fun to look at the opposite end of the spectrum, and anyone who craves such change of pace should check out DSS43’s upgrade currently underway.

Part of NASA’s Deep Space Network (DSN) built to communicate with spacecraft that venture far beyond Earth, Deep Space Station 43 is a large dish antenna with a diameter of 70 meters and largest of the Canberra, Australia DSN complex. However, the raw reflective surface area is only as good as the radio equipment at its center, which are now outdated and thus focus of this round of upgrades.

The NASA page linked above offers a few pieces of fun trivia about DSS43 and its capabilities. If that whets an appetite for more, head over to Twitter for a huge treasure trove. Whoever is in charge of Canberra DSN’s Twitter account has an endless fountain of facts and very eager to share them in response to questions, usually tagged with #DSS43. Example: the weight of DSS43 is roughly 8.5 million kilograms, 4 million of which is moving structure. They also shared time lapse video clips of work in progress, one of which is embedded after the break.

Taking the uniquely capable DSS43 offline for upgrades does have some consequences, one of which is losing our ability to send commands to distant interplanetary probe Voyager 2. (Apparently smaller DSN dishes can be arrayed to receive data, but only DSS43 can send commands.) Such sacrifices are necessary as an investment for the future, with upgrade completion scheduled for January 2021. Just in time to help support Perseverance (formerly “Mars 2020”) rover‘s arrival in February and many more missions for years to come.

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How Early Radio Receivers Worked

July 10, 2020 by 43 Comments

If you’ve ever built a crystal radio, there’s something magical about being able to pull voices and music from far away out of thin air. If you haven’t built one, maybe you should while there’s still something on the AM band. Of course, nowadays the equivalent might be an SDR. But barring a computer solution, there are not many ways to convert radio waves into intelligence. From a pocket radio to advanced RADAR to a satellite in orbit, receiving a radio wave is accomplished in pretty much the same way.

There are, however, many ways to modulate and demodulate that radio wave. Of course, an AM radio works differently than an FM radio. A satellite data downlink works differently, too. But the process of capturing the radio wave from the air and getting them into a form ready for further processing hasn’t changed much over the years.

In this article, I’ll talk about the most common radio receiver architectures you may have seen in years past, and next week I’ll talk about modern architectures. Either way, understanding receiver architectures will help you design new radios or troubleshoot them.

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Software Defined Radio Academy Goes Virtual

July 8, 2020 by 4 Comments

They say every cloud has a silver lining. It’s hard to find a positive among all the bad news about the current global pandemic, but it has pushed more conferences and events to allow online participation either live or after the fact. A case in point: The Software Defined Radio Academy’s annual event is all on a YouTube channel so you can attend virtually.

Not all the videos are there yet, but the keynote along with some very technical talks about techniques ranging from FPGAs to spectrum monitoring and spectral correlation density — you can see that video, below. We presume you’ll eventually be able to watch all the presentations listed in the program.

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Breadboard Breaks The Speed Barrier

July 1, 2020 by 12 Comments

It is common wisdom that solderless breadboards are only good for low frequencies. But how fast can they really go? There’s been a contest going on to see who can make the fastest breadboard-mounted oscillator and [Joe Smith] has been trying to keep his leading position. He’s already managed 6 GHz and now he’s shooting for 20 GHz, as you can see in the video below.

One of the biggest challenges at these frequencies is just measuring your output. You may have a scope, but how does it do at 20 GHz? So half of the story is how [Joe] managed to monitor his output.

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