[Carl] just found a yet another use for the RTL-SDR. He’s been decoding Inmarsat STD-C EGC messages with it. Inmarsat is a British satellite telecommunications company. They provide communications all over the world to places that do not have a reliable terrestrial communications network. STD-C is a text message communications channel used mostly by maritime operators. This channel contains Enhanced Group Call (EGC) messages which include information such as search and rescue, coast guard, weather, and more.

Not much equipment is required for this, just the RTL-SDR dongle, an antenna, a computer, and the cables to hook them all up together. Once all of the gear was collected, [Carl] used an Android app called Satellite AR to locate his nearest Inmarsat satellite. Since these satellites are geostationary, he won’t have to move his antenna once it’s pointed in the right direction.

As far as antennas go, [Carl] recommends a dish or helix antenna. If you don’t want to fork over the money for something that fancy, he also explains how you can modify a $10 GPS antenna to work for this purpose. He admits that it’s not the best antenna for this, but it will get the job done. A typical GPS antenna will be tuned for 1575 MHz and will contain a band pass filter that prevents the antenna from picking up signals 1-2MHz away from that frequency.

To remove the filter, the plastic case must first be removed. Then a metal reflector needs to be removed from the bottom of the antenna using a soldering iron. The actual antenna circuit is hiding under the reflector. The filter is typically the largest component on the board. After desoldering, the IN and OUT pads are bridged together. The whole thing can then be put back together for use with this project.

Once everything was hooked up and the antenna was pointed in the right place, the audio output from the dongle was piped into the SDR# tuner software. After tuning to the correct frequency and setting all of the audio parameters, the audio was then decoded with another program called tdma-demo.exe. If everything is tuned just right, the software will be able to decode the audio signal and it will start to display messages. [Carl] posted some interesting examples including a couple of pirate warnings.

If you can’t get enough RTL-SDR hacks, be sure to check out some of the others we’ve featured in the past. And don’t forget to send in links to your own hacking!

There is no single and definitive definition of what hacking is. We all have different versions of similar ideas in our head, but depending on your background and area of enthusiasm, hacking means something different. While dictionary.com has many definitions of the word itself, none seem to cover what we see on a daily basis.

We set out to define “hacking” ourselves. We tossed around words like “modify”, “kludge”, “explore”, and “create”. Each time we committed an increasingly vague definition onto the page, we decided it was too narrow and tossed it in the proverbial trash. The variations were just too many.

What we do know is that “hacking” seems to breed advancement and innovation. Much like mutations in an evolutionary chain, each hack pushes the topic in a slightly new direction, inspiring others and thereby perpretuating the evolutary event. In a very short time we’ve witnessed hacking bring forth the evolution of wagons to cars, kites to airplanes, and the creation of the computer.

We at Hackaday would like to declaire August 11th to be “International Hack Day”. A day to celebrate hacking in all of its diverse forms. From soldering to sewing, coding to carbonating, knitting to knurling, we want you to keep on hacking. Take August 11th as a day to show pride in your hacking. Waive your hacker flag high and educate those around you.

We have asked many of our friends to contribute their personal definition of hacking. Here they are, in the order they were received.

Hacking is being completely obsessed with a puzzle that shares it’s solution with everyone once it’s solved.
— Limor “Ladyada” Fried, Adafruit

I don’t hacking is something you do, it’s a mindset, you look at the same world as everyone else, filled with the same things, things that are assumed to do just one thing or what we’re told they should do… but you constantly ask yourself “what else can I make this thing do?”.
— Phil Torrone: Adafruit, MAKE Magazine & Founder of Hack-a-day

hacking is the noble art of tricking hardware or software into doing something unexpected. — Leo LaPorte

Hacking’ is the process of exploring and understanding a system. A ‘hack’ is the application of that gained knowledge in a clever and novel way. — Andrew “Bunnie” Huang

I would say a “hack” is anytime you extend a know system beyond its intended functionality. Quite often this results in features a product might have had if its designers didn’t have to meet a ship date. —Benjamin Heckendorn

Taking what exists, learning what you can about it, improving upon it, and sharing it. — Mitch Altman

Repurpose, reuse, invent, and recycle.” Not just duct taping stuff together, it applies to code, ideas, whatever. — Ian Lesnet, Dangerous Prototypes

Hacking means building with less regard for the polished nature of the final project. Think MacGyver meets electronics. He was never building something to sell, he just had to get the job done. Whether we are deconstructing a device or building something new and completely wacky, hacking it means we don’t care what other people think of our methods, we’re more concerned about what people think of the outcome. — Nathan Seidle, Sparkfun

Hacking is technical dissection that leads to discovery of function and exploration of repurposed or enhanced usability. — Lindsey Levkoff, Education at Sparkfun

To me, “hacking” means that I can bend my environment to my liking. I have the understanding, will and ability to rearrange the world into something that is most palatable to me. Hacking is power. — Pete Doktor, Engineering at Sparkfun

Hacking is making a mess of a solution then refining it until someone else acknowledges that you have done something of interest. — Mikey Sklar

Hacking is many things to many people. To me, it’s about stirring things up, not accepting blindly whatever it is you’re told, seeking out the answers firsthand, and sharing what you discover with others so they can embark on their own journey. Note the absence of computers or even technology in this definition. They are not essential in being a hacker. If you look at every instance of exploration, creative expression, journalistic investigation, or even rebellion, you will find the basic components of hacking. The modern age simply gives us more tools with which to use them.
— Emmanuel Goldstein

We would love to see all of your definitions of hacking. Sure, many may be similar, but you’ll probably find that many are very different. Here are the current writer’s definitions:

To me, hacking is more of a mindset. When you’re just tearing into something headed toward some goal without the proper research and planning. There’s an excitement there, like you’re exploring. — Caleb Kraft

Use things in a way in which they were not originally intended. — Mike Szczys

Modifying something from it’s original use to do something that it was never intended to do.  Although much (but not all) legal hacking is done for fun and not necessaryil profit, sometimes a device or technique is hit upon that changes society and hopefully brings the author the monetary reward he or she deserves. — Jeremy Cook

Hacking is all about learning. Gaining just enough knowledge to know how something works, and then using that knowledge to improve upon or just mess with it. To me, things start getting very interesting when simple tricks lead to things you aren’t supposed to know. — Jesse Congdon