software-defined radio

122 Articles

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” →

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.

Hackaday Links: July 20, 2012

July 20, 2012 by 13 Comments

Hey, it’s the 43rd anniversary of men first walking on the moon. Here’s some stuff we found to celebrate that. Fun trivia: for Apollo 11, [Neil] and [Buzz] didn’t go more than 200 feet from the LEM.

This is so incredibly sad

Remember Heathkit? A lot of cool kit-based electronics came from them. They’re out of business, but you can get all the Heathkit swag you can imagine from the repo man. A ton of stuff from the old Heathkit headquarters is being auctioned off in Byron Center, Michigan this Tuesday, July 24. Notable lots include a HE-Robot and a nice pair of o’scopes. If someone wants to pick up one of the catalog lots for us, we’d be thankful.

Troll Physics: ‘What is with this guy’ edition

We’ve seen [Fredzislaw]’s LED trickery before. The first time was a crazy 3 LED circuit, the reveal of which showed two AC power supplies in a battery connector. This time, [Fred] has two switches and an LED. Turn one switch on, the LED lights up. Turn that switch off and flip the other one, the LED still lights up. Turn both switches on, the LED goes off. Your guess is as good as ours.

Prototyping with a key fob remote

[Gary] wrote in to tell us about the dev board he’s been working on. It has either a PIC or AVR on the back side, broken out into 0.1 inch headers on the front. There’s a small solderless breadboard and an on-board RF link that uses a five-button key fob remote. Seems very useful, no matter what side of the PIC/AVR holy war you’re on.

Consumer Alerts: Software defined radio

Over on the RTLSDR subreddit, [photoscotty] bought this TV tuner dongle from Deal Extreme and received the inferior EZTV645 tuner. Unsurprisingly, Chinese manufacturers will just grab whatever is available, put it in an envelope, and ship it off on a slow boat from China. [photoscotty] is trying to return his dongle to DX, but until Sparkfun or Adafruit start selling these things (yes, there’s a market now get on it) you’ll have to be careful out there.

Wouldn’t this feel terrible against your skin all day?

[Colin] printed a watch band on his Makerbot. Apparently Shenzhen humidity didn’t play nicely with his nylon strap, so [Colin] made his own out of plastic. It’s flexible and has a neat looking clasp, as well as an awesome demo for what a 3D printer can actually do. Thingiverse files here.

Software-Defined Radio Remotely Using A Linux Wall wart

July 9, 2012 by 18 Comments

Here’s a interesting idea; if the hardware seen above is dropped at a location, you can monitor radio signals remotely via the Internet. [MS3FGX] has been toying with the idea for a little while now. He wanted to use a DVB dongle with a portable Linux solution to offer Software-Defined Radio (SDR) capability without the need to actually be there.

The white box is a PWN Plug, a branded version of the SheevaPlug. The black dongle that plugs into it is a DVB tuner dongle. It’s meant to receive television signals over the radio, but recently the hardware has been used as a simple way to implement SDR. Combine the two (along with the antenna), stir in a network connection, and you’ve got a remote listening post. What can you listen to? Just about anything that’s within the dongle’s bandwidth range. [MS3FGX] mentions walkie-talkie traffic and pager signals, to name just two.

He even wrote an installation script that gets you up and running in no time.

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.