Building A Better Software Defined Radio (and Transmitting As Well)

October 24, 2012 by 39 Comments

By now most Hackaday readers should be familiar with this year’s latest advance in software defined radio. With a simple USB TV tuner dongle, it’s possible to receive FM broadcasts, GPS data from satellites, and even telemetry from aircraft flying overhead. There is one limitation to this setup, though: it’s receive only. Hacker extraordinaire [Michael Ossmann] is looking to make a better software defined radio called the HackRF.

The HackRF is an incredibly ambitious project – able to receive just about anything between 100 MHz and 6 GHz (this includes everything from the top of the FM radio band to cordless phones, cell phones, WiFi, and basically any radio technology that has been commercialized in the last 15 years), the HackRF is also able to transmit. Yes, with the HackRF it’s possible to build your own software-defined WiFi module, or just broadcast bogus GPS information.

Compared to the $20 TV tuner SDR dongles we’ve played around with, the HackRF isn’t exactly cheap. [Mossmann] figures he’ll be able to sell the device for about $300. A fair bit of change, but much, much less than professional, commercial SDR solutions.

A very cool advance in the state of SDR, but reason dictates we must suggest that everyone who wants a HackRF to start studying for their amateur radio exam now. Being a licensed radio operator won’t stop you from any sort of malicious intent, but with at least with licensing comes with the possibility of knowing what evil you’re doing.

You can check out the wiki for the HackRF over on the gits along with the current hardware design

Still More Software Defined Radio Fun On The Mac

October 12, 2012 by 9 Comments

Even though the world of software defined radio started out as a Linux-only endeavor, several recent software releases have put the ball fully into the court of OS X users. [hpux735]’s new Cocoa Radio release provides a (nearly) fully functional software defined radio for anyone with a USB TV tuner and a mac.

Earlier this week, we saw (and tested)  [Elias]‘ port of gqrx and were reasonably impressed. [hpux735]’s app does the same job and also provides the source so you can compile it yourself.

Previously, [hpux735] ported the osmocom driver for these RTL2832U-based USB TV tuner dongles to the Mac and wrote a small Cocoa driver. The new Cocoa Radio software uses this driver and adds all the features you’d expect from a software radio package; in the title pic for this post, you can see a top 40 radio station near my house and their insipid hatred of dynamic range.

[hpux735] posted a few videos of his development process. You can check those out after the break.

Continue reading “Still More Software Defined Radio Fun On The Mac” →

OS X Port Of Gqrx Is The Easiest Way To Get Into Software Defined Radio

October 8, 2012 by 18 Comments

Many have tried to put together an easy package for running software defined radio packages on the Mac. Not many have succeeded the way [Elias]’ port of the gqrx SDR package has. It’s simply the easiest way to get a software defined radio up and running on the mac.

gqrx is a front end for the very popular GNU Radio software defined radio toolkit. Originally designed for the FUNcube SDR dongle, gqrx can also be made to work with one of the many, many USB TV tuners that have come out of China this past year for use as a software radio.

[Elias]’ port of gqrx isn’t the first app to put software defined radio on the Mac, but it certainly is the easiest. Simply by downloading [Elias] disk image, plugging in a TV tuner dongle, and starting the app, I was able to have a software radio receiver on my MacBook Air in less than a minute.

Everything required by GNU Radio and gqrx is already included, making this the easiest way to get SDR on a Mac. Very awesome work from [Elias], and we thank him.

Real Time GPS Decoding With Software Defined Radio

August 19, 2012 by 30 Comments

In case the Realtek RTL2832u-based USB TV tuner dongle isn’t useful enough, the folks behind a project to get a software defined GPS receiver off the ground successfully plotted GPS data in real-time with this very inexpensive radio.

Previously, we’ve seen these dongles grab data from GPS satellites – useful if you’re building a GPS-based clock – but this build required hours of data collection to plot your location on a map.

The folks working on the GNSS-SDR project used an RTL2832 USB TV tuner and a Garmin active GPS antenna to track up to four GPS satellites in real-time and plot a location accurate to about 200 meters.

The Google Earth plot for this post shows the data collected by the GNSS-SDR team; the antenna was fixed at the red arrow for the entirety of the test, and the  yellow lines represent a change in the calculated location every 10 seconds. Amazing work, and only goes to show what this remarkable piece of hardware is capable of.

Adding More Frequencies To Your Software Defined Radio

July 8, 2012 by 32 Comments

[regveg] was looking for a way to receive signals outside the normal 64-1700MHz range his TV tuner software defined radio dongle can get. After finding a few $100+ upconverters on the Internet, he stumbled across a DIY project that greatly expands the frequencies his RTLSDR can receive.

[George]’s upconverter uses heterodyning to increase the frequencies received by a SDR dongle. The basic idea is mixing a signal from an antenna with a 100MHz frequency oscillator. The resulting output will be λ + 100MHz and λ – 100MHz, allowing for a wider range of frequencies that can be received by the SDR TV tuner dongle.

Now [regveg] has a board and schematic that makes it possible to receive just about anything with his TV tuner dongle. Interestingly, this upconverter contains less than $10 in parts and is easily etched at home thanks to a single-sided construction and through-hole parts.

As a small aside, [Andrew] sent in a tip a few days ago telling us his RTL dongle didn’t have any ESD protection. This is a very bad thing, but the good news is the fix is very cheap: just solder in a 10 cent diode and you’re good to go.

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?