Why Should You Get a Ham Radio License?

Several of the authors you read on Hackaday are ham radio operators and we’ve often kicked around having a Hacker Chat about “Why be a ham today?” After all, you can talk to anyone in the world over the Internet or via phone, right? What’s the draw?

The Radio Society of Great Britain had the same thought, apparently, and produced a great video to answer the question. They mention the usual things: learning about technology, learning about people in other parts of the world, disaster communications, and radiosport (which seems to be more popular outside the United States; people compete to find hidden transmitters).

In addition, they talked a lot about how hams get involved with space communications, ranging from talking via satellites, to talking to people on the space station, to actually building small satellites. As the narrator says, there are “hundreds of ways to have techie fun” with ham radio.

One thing we noticed they showed but didn’t say a lot about, though, is the educational opportunities. You can learn a lot, and working with kids to help them learn is often very rewarding (and you usually learn something, too). Just to forestall the comments that this post isn’t hack related, we’ll note two things: there is a Raspberry Pi shown and just past the two-minute mark, there is a very clever hacked together Morse code key.

We talk a lot about ham radio, ranging from Arduino-based digital modes to putting together portable stations (you can see a similar one in the video, too). One other thing we noticed they don’t mention: it is generally much easier to get a license today than ever before. Most countries (including the United States) have abolished the Morse code requirements, so while some hams still enjoy CW (hamspeak for operating Morse code), it isn’t a requirement.

Video below.

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RC Glider Flies By Twisting Its Wings

Remote control gliders typically fly like their full-size counterparts. Tail and wing rudders control the direction of flight — but what if the wings themselves could twist and change their profile, similar to that of a bird? Well, RC glider manufacturer [Jaro Müller] did just that — and it is pretty cool (You’ll need a translation to read it though).

Called the Mini Ellipse, the RC glider is designed to be able to fly in slow thermals and maneuver even better than previous models. The entire wing profile can be controlled by wing flexion — the wing itself is very flexible. Unfortunately we don’t have any info about how it actually goes about doing that, but it’s probably either servo motors pulling wires, or maybe nitinol memory wire… but we’re just guessing. Regardless — take a look at the following video and let us know what you think!

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TEMPEST: a Tin Foil Hat for Your Electronics and Their Secrets

Electronics leak waves and if you know what you’re doing you can steal people’s data using this phenomenon. How thick is your tinfoil hat? And you sure it’s thick enough? Well, it turns out that there’s a (secret) government standard for all of this: TEMPEST. Yes, all-caps. No, it’s not an acronym. It’s a secret codename, and codenames are more fun WHEN SHOUTED OUT LOUD!

The TEMPEST idea in a nutshell is that electronic devices leak electromagnetic waves when they do things like switch bits from ones to zeros or move electron beams around to make images on CRT screens. If an adversary can remotely listen in to these unintentional broadcasts, they can potentially figure out what’s going on inside your computer. Read on and find out about the history of TEMPEST, modern research, and finally how you can try it out yourself at home!

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How To Control Siri Through Headphone Wires

Last week saw the revelation that you can control Siri and Google Now from a distance, using high power transmitters and software defined radios. Is this a risk? No, it’s security theatre, the fine art of performing an impractical technical achievement while disclosing these technical vulnerabilities to the media to pad a CV. Like most security vulnerabilities it is very, very cool and enough details have surfaced that this build can be replicated.

The original research paper, published by researchers [Chaouki Kasmi] and [Jose Lopes Esteves] attacks the latest and greatest thing to come to smartphones, voice commands. iPhones and Androids and Windows Phones come with Siri and Google Now and Cortana, and all of these voice services can place phone calls, post something to social media, or launch an application. The trick to this hack is sending audio to the microphone without being heard.

googleThe ubiquitous Apple earbuds have a single wire for a microphone input, and this is the attack vector used by the researchers. With a 50 Watt VHF power amplifier (available for under $100, if you know where to look), a software defined radio with Tx capability ($300), and a highly directional antenna (free clothes hangers with your dry cleaning), a specially crafted radio message can be transmitted to the headphone wire, picked up through the audio in of the phone, and understood by Siri, Cortana, or Google Now.

There is of course a difference between a security vulnerability and a practical and safe security vulnerability. Yes, for under $400 and the right know-how, anyone could perform this technological feat on any cell phone. This feat comes at the cost of discovery; because of the way the earbud cable is arranged, the most efficient frequency varies between 80 and 108 MHz. This means a successful attack would sweep through the band at various frequencies; not exactly precision work. The power required for this attack is also intense – about 25-30 V/m, about the limit for human safety. But in the world of security theatre, someone with a backpack, carrying around a long Yagi antenna, pointing it at people, and having FM radios cut out is expected.

Of course, the countermeasures to this attack are simple: don’t use Siri or Google Now. Leaving Siri enabled on a lock screen is a security risk, and most Androids disable Google Now on the lock screen by default. Of course, any decent set of headphones would have shielding in the cable, making inducing a current in the microphone wire even harder. The researchers are at the limits of what is acceptable for human safety with the stock Apple earbuds. Anything more would be seriously, seriously dumb.

Could You Repeat That?

Ever been out in a big field and need to tell something to Joe at the other end? If you’re lucky Sally is in between and you can shout to Sally to tell Joe your message. Maybe Joe shouts back to Sally in reply.

That’s how amateur radio repeaters work.

Friend of Hackaday [Kenneth Finnegan] got tired of explaining the details of repeaters so he put together a pair of repeater tutorial videos, the first of which is found after the break.

Image source KV5R

The higher radio frequencies, say 50 MHz and above, typically only propagate within line of sight. Add in limited power and antennas from a hand-held, typically under 5 watts and the ubiquitous ‘rubber ducky’ antenna, and you cannot talk very far. Mobile rigs in vehicles with 50 watts and larger antennas do better but in reality they don’t help all that much.

What really makes an improvement is height to improve range. Height provides a longer line of sight with fewer obstructions. Hams created repeaters and put them on towers, buildings or hill tops to expand the radio horizon. The ultimate repeaters are space satellites. Can’t get much higher than that. A close second are balloons going to near space altitudes with repeaters which will provide multi-state coverage.

Besides providing height, a repeater will also have higher output power and much better antennas, especially important for receiving weak signals from distant handhelds. A signal comes in and is repeated back out on a slightly different frequency. All modern ham gear on these frequencies is setup to handle this offset frequency operation.

Whether hams came up with the idea is arguable, but they were certainly there during the early days.

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SDR Tutorials From Michael Ossmann

If you’re just getting into software-defined radio (SDR) but you find some of the math and/or terminology a bit of hurdle, you could absolutely do worse than to check out these SDR tutorials by [Michael Ossmann]. While they’re aimed at people using his HackRF One tool (which we love), most of the tutorial videos are very generally applicable, and we realized that we hadn’t mentioned them explicitly before. Shame on us!

Ossmann focuses on SDR using the open-source GNURadio Companion GUI tool, which makes implementing a lot of cool SDR techniques as easy as dragging and dropping items into a flow diagram. If you want an overview of GNURadio or SDR in general, these videos are a must-watch.

In particular, we loved his entries on complex numbers and complex numbers in DSP because he goes through the whole rationale behind using imaginary numbers in radio work with a graphical presentation that helps add rationale to the otherwise slightly spooky math. Heck, watch these two even if you’re not interested in radio.

The newest entry, covering DSP filters includes a great hands-on introduction to finite impulse response (moving average) digital filters. We really like the practical, simulation-based approach presented in the video — it’s just perfect for a quick introduction.

So if you’re looking for a relatively painless way to get into SDR, grab yourself an RTL-SDR dongle, burn yourself a GNURadio Live DVD, and work through these videos.

Original Hackers’ New Satellite in Orbit

Ham radio put another satellite in orbit, the FOX-1A. Not many groups have the long-term hacking credentials of hams. Their tradition extends back to the first days of radio communications, which puts the group well over a century old. This newest satellite launched in the early hours of October 8th and, after deployment, was heard later the same day. Anyone with the ability to listen on the 2m band can hear FOX-1A. Tatlas-v-rocket-launches-nrol55-cubesatshose licensed as hams will be able to communicate using a 70cm transmitter while listening on 2m.

This satellite is using the cube-sat format and ‘ride sharing’ through a program offered by NASA and the National Reconnaissance Office (NRO). Twelve other nano-satellites rode along with the FOX-1A. These 10 cm cubes are used for commercial, educational, and non-profit projects. The purpose of today’s satellites covered not only ham radio but educating students in satellite construction, land management by American Indian tribes, and space to ground laser communication. Yeah, what’s cooler than space lasers? Video about the FOX-1A after the break.

We’ve seen some interesting ideas for cube-sats. And if you want to think about the ground portion of a system like this, check out the SatNOGs story — winners of the 2014 Hackaday Prize.

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