Listen To The Globe

January 2, 2017 by Al Williams 19 Comments

There was a time when electronic hackers (or hobbyist, enthusiasts, geeks, or whatever you want to be called) were better than average at geography. Probably because most of us listened to shortwave radio or even transmitted with ham radio gear. These days, if you try listening to shortwave, you have to be pretty patient. Unless you want to hear religious broadcasters or programming aimed at the third world, there’s not much broadcast traffic to listen to anymore

The reason, of course, is the Internet. But we’ve often thought that it isn’t quite the same. When you tuned in London on your homebrew regenerative receiver, you wanted to know where that voice was coming from, and you couldn’t help but learn more about the area and the people who live there. Tune into a BBC live stream on the Internet, and it might as well be any other stream or podcast from anywhere in the world.

The New Shortwave

Maybe we need to turn kids on to Radio Garden. Superficially, it isn’t a big deal. Another catalog of streaming radio stations. You can find plenty of those around. But Radio Garden has an amazing interface (and a few other unique features). That interface is a globe. You can see dots everywhere there’s a broadcast station and with a click, you are listening to that station. The static and tuning noises are a nice touch.

Continue reading “Listen To The Globe” →

Run Your Own Numbers Station

December 31, 2016 by Zoe Skyforest 26 Comments

Numbers stations are shortwave stations that broadcast cryptic messages that are widely assumed to be used for communications between nation states and spies. But who’s to say it’s up to the government to have all the fun? If you’ve always dreamed of running your own spy ring, you’ll need a way to talk to them too. Start with this guide on how to run your own numbers station.

The requirements are simple – you just need random numbers, one time pads for each recipient (available from our store!) and a way to send the audio – ideally a powerful shortwave transmitter, but for an intelligence agency on a budget, online streaming will work. Then you’re ready to send your message. [Jake Zielke] shares techniques on how to easily encode a message into numbers for transmission, and how to encrypt them with one time pad techniques. Done properly, this is an unbreakable form of encryption. [Jake] then rounds out the guide with tips on how to format your station’s transmissions to address multiple secret agents effectively.

It’s a great way to get started in the world of spooky secret radio communications. All the tools needed to get started are available on the page, so you’ll be up and running in no time. Meanwhile, why not do a little more research on the history of numbers stations?

B Battery Takes A 9V Cell

December 23, 2016 by Al Williams 21 Comments

Old American radios (and we mean really old ones) took several kinds of batteries. The A battery powered the filaments (generally 1.5V at a high current draw). The B battery powered the plate (much lower current, but a higher voltage–typically 90V). In Britain these were the LT (low tension) and HT (high tension) batteries. If you want to rebuild and operate old radios, you have to come up with a way to generate that B voltage.

Most people opt to use an AC supply. You can daisy-chain a bunch of 9V batteries, but that really ruins the asthetics of the radio. [VA3NGC] had a better idea: he built a reproduction B battery from a wooden box, some brass hardware, a nixie tube power supply, and a 9V battery (which remains hidden). There’s also a handful of zener diodes, resistors, and capacitors to allow different taps depending on the voltage required.

The project looks great. The wooden box apparently was a recycle item and the brass hardware makes it look like it belongs with the old radios it powers. This is a good example of how there’s more to vintage restoration than just the electronics. Sure, the function is important, but to really enjoy the old gear, the presentation is important, too.

Not all tube radios took 90V B+, but since this battery has taps, that isn’t a problem. The old Radio Shack P-Box kit took 22.5V. Of course, if you are going to build your own battery, maybe you ought to build your own triodes, too.

Hacked Diamond Makes Two-Atom Radio

December 20, 2016 by Dan Maloney 14 Comments

It used to be pretty keen to stuff a radio receiver into an Altoid’s tin, or to whip up a tiny crystal receiver from a razor blade and a pencil stub. But Harvard researchers have far surpassed those achievements in miniaturization with a nano-scale FM receiver built from a hacked diamond.

As with all such research, the experiments in [Marko Lončar]’s lab are nowhere near as simple as the press release makes things sound. While it’s true that a two-atom cell is the minimal BOM for a detector, the device heard belting out a seasonal favorite from [Andy Williams] in the video below uses billions of nitrogen-vacancy (N-V) centers. N-V centers replace carbon atoms in the diamond crystal with nitrogen atoms; this causes a “vacancy” in the crystal lattice and lends photoluminescent properties to the diamond that are sensitive to microwaves. When pumped by a green laser, incident FM radio waves in the 2.8 GHz range are transduced into AM fluorescent signals that can be detected with a photodiode and amplifier.

The full paper has all the details, shows that the radio can survive extreme pressure and temperature regimes, and describes potential applications for the system. It’s far from a home-gamer’s hack at this point, but it’s a neat trick and one to watch for future exploitation. In the meantime, here’s an accidental FM radio with a pretty small footprint.

Continue reading “Hacked Diamond Makes Two-Atom Radio” →

The Engines Of Ingenuity

December 17, 2016 by Elliot Williams 10 Comments

Every once in a while, we stumble on an amazing resource that’s not exactly new, but it’s new to us. This is the case, in spades, with The Engines of Our Ingenuity, a radio show that’s been running since 1988!

Each episode covers an invention or engineering marvel, and tells the story of how it came to be, and puts each device into its historical and cultural context. Want to get the lowdown on how we safely bring fire into the kitchen? Or the largest land transport vehicle, NASA’s crawler? And what’s up with lobsters anyway?

Continue reading “The Engines Of Ingenuity” →

RainCube Spreads Its Umbrella

December 9, 2016 by Jenny List 15 Comments

There are times when a mechanism comes to your attention that you have to watch time and time again, to study its intricacies and marvel at the skill of its designer. Sometimes it can be a complex mechanism such as a musical automaton or a mechanical loom, but other times it can be a device whose apparent simplicity hides its underlying cleverness. Such a moment came for us today, and it’s one we have to share with you.

RainCube is a satellite, as its name suggests in the CubeSat form factor and carrying radar instruments to study Earthly precipitation. One of the demands of its radar system is a parabolic dish antenna, and even at its 37.5 GHz that antenna needs to be significantly larger than its 6U CubeSat chassis.

It is the JPL engineers’ solution to this problem that is the beautiful mechanism we want to show you. The parabola is folded within itself and tightly furled round the feedhorn within the body of the satellite. As the feedhorn emerges, first the inner sections unfurl and then the outer edge of the parabola springs out to form the dish antenna shape. Simultaneously a mechanism of simplicity, cleverness, and beauty, one we’d be very proud of if it were our creation.

There is nothing new in collapsible parabolas used in spacecraft antennas, petal and umbrella-like designs have been a feature of some of the most famous craft. But the way that this one has been fitted into such a small space (and so elegantly) makes it special, we hope you’ll agree.

[via space.com]

An Amateur Radio Repeater Using An RTL-SDR And A Raspberry Pi

December 5, 2016 by Jenny List 12 Comments

An amateur radio repeater used to be a complex assemblage of equipment that would easily fill a 19″ rack. There would be a receiver and a separate transmitter, usually repurposed from commercial units, a home-made logic unit with a microprocessor to keep an eye on everything, and a hefty set of filters to stop the transmitter output swamping the receiver. Then there would have been an array of power supply units to provide continued working during power outages, probably with an associated bank of lead-acid cells.

More recent repeaters have been commercial repeater units. The big radio manufacturers have spotted a market in amateur radio, and particularly as they have each pursued their own digital standards there has been something of an effort to provide repeater equipment to drive sales of digital transceivers.

But what if you fancy setting up a simple repeater and you have neither a shed full of old radios or a hotline to the sales department of a large Japanese manufacturer? If you are [Anton Janovsky, ZR6AIC], you make your own low-powered repeater using an RTL-SDR, a low-pass filter, and a Raspberry Pi.

[Anton]’s repeater is a clever assemblage through pipes of rtl_sdr doing the receiving, csdr demodulating, and [F5OEO]’s rpitx doing the transmitting. As far as we can see it doesn’t have a toneburst detector or CTCSS to control its transmission so it is on air full-time, however we suspect that may be a feature that will be implemented in due course.

With only a 10 mW output this repeater is more of a toy than a useful device, and we’d suggest any licensed amateur wanting to have a go should read the small print in their licence schedule before doing so. But it’s a neat usage of a Pi and an RTL stick, and with luck it’ll inspire others in the same vein.

We’ve touched on the Pi as a transmitter before, from a straightforward broadcast FM unit to crossing continents with WSPR, and even transmitting digital TV in another [F5OEO] hack.