software-defined radio

123 Articles

Getting Started With Software Defined Radio

June 27, 2012 by 33 Comments

In the last few months, software defined radio has seen an explosion in popularity thanks to a small USB TV tuner dongle able to receive anything broadcast between 64 and 1700 MHz. It’s a very neat project that opens the door to a whole bunch of radio experimentations, but getting started in the SDR world can be a bit daunting. To help everyone out, [MS3FGX] is writing a getting started guide so everyone can get into the world of software defined radio.

After getting one of the TV tuners supported by the RTL-SDR project (by far the most commonly used is this one from Dealextreme), the next thing you’ll need is a decent antenna. [MS3FGX] has had some success with this Radio Shack antenna, but it’s very easy to make your own.

The most popular software package to use with the RTL TV dongle is GNU Radio, and [MS3FGX] goes over the ins and outs of setting this up along with a brief aside for the Gqrx receiver.

After your hardware and software is set up, the only thing left to do is tuning into a few of your favorite stations. The range of frequencies the RTL covers includes AM and FM radio, along with GSM and GPS signals. Of course there’s a whole lot more you can do with this project like listening in on your car’s keyless entry fob, pagers, and wireless weather stations.

Two Software Defined Radio Hacks From Our Resident SDR Guru

June 16, 2012 by 13 Comments

It seem [Balint] is becoming somewhat of a SDR guru around these parts; in the past few months, he’s gotten a USB TV tuner receiver working with GNU Radio, started a software defined radio tutorial YouTube channel, and even used this project to listen in on conversations between airplanes and air traffic control. This time, [Balint] is back using this cheap USB TV tuner for radio direction finding and running HDSDR in Linux and OS X.

[Balint]’s radio direction finding presentation goes over traditional means of direction finding using the doppler effect and mechanically rotated antennas. Because [Balint] is dealing with frequencies around 150MHz (about 2 meter wavelength), building a physical direction finding setup requires spinning antennas at around 40,000 RPM; much to fast for any hardware build. [Balint]’s solution was to attach 4 antennas around the circumference of a circle and electronically switch between them many thousands of times a second. [Balint] put up a wiki page going over all the theory and implementation details of his build.

[Balint] also put wrote up a neat app to control software defined radios – including the Realtek TV dongle –  over a network. Spread over a wide enough geographic area, it could become extremely easy for anyone to play air traffic controller. The BorIP Server can also be used to run HDSDR in Linux and OS X under Wine; just connect HDSDR to the network loopback on the same machine, and you get around Wine’s distaste for accessing hardware natively.

Awesome work, and we can’t wait to see what comes out of [Balint]’s laboratory next.

Edit: instead of the dongle, [Balnt] is using a ‘real’ software radio board. A lot of people are messaging him asking if the same method of direction finding is possible with the dongle. Here’s what [Balint] has to say:

The trick, as I see it, would be to create some (more or less simple) additional hardware to take the clock signal straight off the dongle’s on-board oscillator and divide it down for use with the antenna switch, i.e. 28 MHz à tens of kHz (this is the bit that’s done in ‘software’ on the FPGA). One problem still remains however: the counter needs to remain calibrated against the known direction the antenna was pointing at the time – otherwise a stop/start of the data stream from the dongle will mean the direction will go out of sync by 90/180/270 degrees each stop/start. Perhaps someone will figure out an elegant solution for this slight hurdle!

So there you go. Up for a challenge?

[Balint] Is Starting A Software-defined Radio Tutorial Series

June 11, 2012 by 26 Comments

A few months ago, we saw a hack where a $20 USB TV tuner was transformed into a software-defined radio capable of reading GPS signals, listening to radio transmissions between aircraft and a control tower, and even a simple FM radio. This project is a perfect introduction to the RTL-SDR and Ham radio scene, but getting these projects up and running can be a bit overwhelming for anyone who hasn’t played around with this before. [Balint] is tackling this problem head on with a series of YouTube tutorials to get SDR noobs up and running with GNU Radio and the Realtec USB TV tuner.

To demonstrate the power of software-defined radio, [Balint] is using GNU Radio and the USB TV tuner that started it all, the Ezcap EZTV668 (conveniently back in stock at DealExtreme, but other options exist). Because software-defined radio is a touch confusing for a beginner to wrap their head around, [Balint] is beginning his tutorial series by explaining radio sources, sinks, and the GNU Radio interface.

Already, [Balint] has put up 5 tutorials and made the flowgraph files available in his gr-baz project. He’s doing a wonderful job opening up the software-defined radio scene to beginners, but he’s still looking for some feedback. If you have a suggestion on what [Balint] should cover next, leave a note in the YouTube comments and we’re sure [Balint] will get around to that eventually.

Improving A Software Defined Radio With A Few Bits Of Wire

May 14, 2012 by 23 Comments

Impressed by the recent advances in the software defined radio scene, [Jason] picked up a $20 USB TV tuner dongle to check out his local airwaves. Unfortunately, the antenna included with the little USB dongle is terrible at receiving any signal other than broadcast TV. [Jason] wanted to improve his reception, so he got some wire and made his own discone antenna.

The discone antenna is ideally suited for [Jason]’s setup – properly constructed, it’s able to receive over the entire 64 to 1700 MHz band the RTL-SDR dongle is able to read. To construct his antenna, [Jason] checked out [VE3SQB]’s list of antenna design programs, got the dimensions of his antenna, and set to work attaching wire to PVC pipe.

The antenna is a massive improvement over the stock antenna included with the TV tuner dongle. After mounting his discone at the far end of his back yard, [Jason] started picking up a few blips from the transponders of passing aircraft.

Putting A Software Defined Radio On A Mac

May 12, 2012 by 12 Comments

A few months ago [Antti Palosaari] discovered cheap USB TV tuners could be used as a software-defined radio. Since then, we’ve seen these TV tuners receive signals from GPS satellites and even the signals between air traffic control and passenger aircraft. Like everything cool, Mac support for these drivers is slightly terrible so [hpux735] wrote his own Cocoa app to support these amazing dongles.

[hpux735]’s driver is a port of the osmocom driver, repackaged as a native Cocoa app so the terribly fickle libusb and other dependencies aren’t needed. All the code is up on GitHub, ready for you to start playing around with SDR.

As far as tutorials for those wading into the deep waters of software-defined radio, a number of how-to guides have popped up over the last month to get SDR noobs up and running quickly. Here’s a few of the best ones we’ve seen:

[braingram] put up an Instructable for Ubuntu users.

For people who have a Windows box lying around [balint] put up a getting started guide.

There’s a slightly more thorough Windows guide here.

Most of the development in the TV tuner SDR community is happening on the RTLSDR subreddit, and there’s more than enough info there to do just about anything with these TV tuner dongles. If you come up with a novel use for one of these dongles, send it in on the tip line.

Playing Air Traffic Controller With Software Defined Radio

April 16, 2012 by 20 Comments

Being an air traffic controller is a very cool career path – you get to see planes flying around on computer screens and orchestrate their flight paths like a modern-day magician. [Balint] sent in a DIY aviation mapper so anyone can see the flight paths of all the planes in the air, with the added bonus of not increasing your risk of heart attack or stroke.

[Balint]’s Aviation Mapper uses software defined radio to overlay RADAR and ACARS messages from aircraft and control towers in an instance of Google Earth running in a web browser. After grabbing all the radio data from a software defined radio, [Balint]’s server parses everything and chucks it into the Google Earth framework. There’s a ton of info, pictures, and explanations of the inner machinations of the hardware on [Balint]’s official project page.

Right now, Aviation Mapper only displays planes within 500 km of Sydney airspace, but [Balint] is working on expanding the coverage with the help of other plane spotters. If you’re willing to help [Balint] expand his coverage, be sure to drop him a line.

Of course, [Balint] is the guy who gave us a software radio source block for those cheap USB TV tuner dongles. Just a few days ago we saw these dongles receiving GPS data, so we’re very impressed with what these little boxes can do in the right hands. [Balint] says his Aviation Mapper application will work with any GNU Radio receiver, so it’s entirely possible to copy his work with a handful of TV tuner dongles.

After the break, there’s two videos of [Balint] sitting at the end of the runway near the Sydney airport watching arrivials come in right above his head and on his laptop. It’s very cool, but we’d be interested in an enterprising hacker in the New York City area copy [Balint]’s work.

Continue reading “Playing Air Traffic Controller With Software Defined Radio” →

Working Software-defined Radio With A TV Tuner Card.

March 30, 2012 by 77 Comments

[Balint Seeber] just sent in a small yet timely project he’s been working on: a software radio source block for the Realtek RTL2832U. Now with a cheap USB TV tuner card, you can jump right into the world of software-defined radio.

[Balint]’s code comes just a week after hackaday and other outlets posted stories about using a $20 USB TV capture dongle for software defined radio. At the time, these capture cards could only write data directly to a file. With [Balint]’s work, anyone can use a cheap tv tuner dongle with HDSDR, Winrad, or GNU Radio. If you’ve ever thought about trying out software-defined radio, now might be the time.

Elsewhere on the Internet, a surprisingly active RTL-SDR subreddit popped up dedicated to using the Realtek RTL2832U tuner for software defined radio. There’s an awesome compatibility chart listing compatible USB dongles. The cheapest (so far, and subject to change) is the Unikoo UK001T available for $11 on eBay.

With his source block, [Balint] can listen to anything on the radio between 64-1700 MHz. The sample depth is 8 bits and the sample rate can be anything up to 3.2 MHz. You can watch [Balint] testing out his $20 GNU Radio rig after the break.

Continue reading “Working Software-defined Radio With A TV Tuner Card.” →