It hasn’t become a household term yet, but Software-Defined Radio (SDR) is a major player on the developing technology front. Whether you’re building products for mass consumption, or just playing around for fun, SDR is worth knowing something about and I’ll prove it to you.
Continue reading “Why You Should Care About Software Defined Radio”
If you’re wondering how to get a better signal on your cellphone, or just want to set up your own private cell network, this one is for you. It’s a GSM base station made with a BeagleBone Black and a not too expensive software defined radio board.
The key component of this build is obviously the software defined radio. [Julian] is using a USRP B200 radio for this project. It’s not cheap, but it is a very nice piece of hardware capable of doing just about anything with GNU Radio. This board is controlled by a BeagleBone Black, a pretty cheap solution that puts the total cost of the hardware somewhere around $750.
The software side of the build is mostly handled by OpenBTS, the open source project for the software part of a cell station. This controls the transceiver, makes calls and SMS, and all the backend stuff every other cell station does. OpenBTS also includes support for Asterisk, the software of choice for PBX and VoIP setups. Running this allows you to make calls and send texts with your SDR-equipped, Internet-enabled BeagleBone Black anywhere on the planet.
[Rich, VE3MKC] has been wanting to get into Software Defined Radio for a while now, but didn’t want to go the usual PC route. He initially thought the Raspberry Pi would be the best platform for a small, embedded device that could manipulate audio, but after discovering the ARM-powered Teensy 3.0, had an entirely different project in mind.
[Rich] is using a SoftRock SDR to take RF from an antenna and downconvert it into the audio range. Doing DSP for SDR is fairly computationally intensive, but he found a Teensy 3.0 with the audio adapter board was more than up to the task.
So far, [Rich] is running the audio from the SoftRock to the Teensy where the audio is digitized and multiplied with a VFO, sent through a filter and then sent to the output of the headphone jack to a speaker. The volume pot on the audio adapter board is used to tune the VFO, something [Rich] be replacing with a proper encoder sometime in the future.
In the videos below, you can see [Rich] listening in on a contest with a tiny TFT display showing everybody on the air. It’s a very cool build, and even though it’s still very early in development, there’s still a whole lot of CPU cycles for the Teensy to do some very cool stuff.
Continue reading “Building A Software Defined Radio With A Teensy”
Last summer in the heyday of software defined radio via USB TV tuners we asked hackaday readers a question: Is anyone using everyone’s favorite method of SDR for radio astronomy? It took nearly a year, but finally there’s an awesome project to turn a USB TV tuner into a radio telescope. It’s from the fruitful mind of [Marcus Leech] (PDF warning), and is good enough to detect the rotation of the galaxy with a three-foot satellite dish.
News of [Marcus]’ work comes to us from [Carl] over at RTL-SDR.com who has been keeping tabs on the advances of building a radio telescope in a backyard. He’s been collecting a lot of interesting tidbits including this gif showing an arm of the galaxy entering and leaving [Marcus]’ telescope’s field of view over the course of a few hours.
Not only can [Marcus]’ telescope record continium measurements – basically, a single-pixel camera sensitive to only one frequency – it can also produce spectral plots of the sky. Combine the ability to measure multiple frequencies at the same time with the Doppler effect, and [Marcus] can measure the rotation of the galaxy with a USB TV tuner. That’s just awesome in our humble opinion.
If you already have an RTL-SDR TV tuner and a largish satellite dish, [Marcus]’ project should be fairly inexpensive to replicate; the feed assembly is made out of a coffee can, the amplifiers are repurposed satellite television equipment, and all the software – [Marcus]’ own simple_ra tool for GNU Radio – is open source. Of course with a 3 foot diameter dish, it will be impossible to replicate the data from huge radio telescopes. Still, it’s an impressive piece of work that leaves us searching craigslist for an old C-band dish.
By now you might have a bit weary of your small and inexpensive TV tuner dongle software defined radio. Yes, using a USB TV dongle is a great introduction to SDR, but it has limited bandwidth, limited frequency range, and can’t transmit. Enter the bladeRF, the SDR that makes up for all the shortcomings of a USB dongle, and also serves as a great wireless development platform.
The bladeRF is able to receive and transmit on any frequency between 300 MHz and 3.8 GHz. This, along with a powerful FPGA, ARM CPU, and very good ADCs and DACs makes it possible to build your own software defined WiFi adapter, Bluetooth module, ZigBee radio, GPS receiver, or GSM and 4G LTE modem.
It’s an impressive bit of kit, but it doesn’t exactly come cheap; the bladeRF is available on the Kickstarter for $400. The folks behind the bladeRF seem to be doing things right, though, and are using their Kickstarter windfall for all the right things like a USB vendor ID.
There’s a video of two bladeRFs being used as a full duplex modem. You can check that out after the break.
Continue reading “BladeRF, Your Next Software Defined Radio”
The University of Kent’s hackerspace, TinkerSoc, recently had a talk on software-defined radio using an incredibly inexpensive USB TV tuner. Of course this is nothing new to Hackaday readers, but they did manage to build one of the best antennas for their TV dongle. It’s a discone antenna, and is perfectly suited for tuning into a whole bunch of really cool things such as weather balloons and aircraft transponders.
The idea discone antenna looks exactly like its namesake; a metal disk attached to a metal cone. Of course with the frequencies the RTL software-defined radio deals with, it’s rarely necessary to build antennas out of sheet metal. The team at TinkerSoc built their discone out of galvanized garden wire and attached it to the input of their TV tuner.
All the dimensions for their discone antenna were gleaned from [ve3sqb]’s antenna design programs. Since TinkerSoc designed their antenna for 110 MHz, it ended up being pretty large. For higher frequencies, though, a discone antenna become fairly small and more than portable enough for a mobile rig.
As the year draws to a close, we must look back and look at the advances in amateur radio this year. The RTL-SDR tuner hack, a USB TV Tuner to create a software defined radio receiver, is one of the greatest hacks of the last 12 months and a great justification for 2012 being the year of software defined radio receivers. 2013 is shaping up to have even more advances in the state of software defined radio. This time we’ll be transmitting as well, possibly with [AE9RB]’s Peaberry SDR transceiver.
The Peaberry SDR transceiver is a kit to both transmit and receive on every HAM band between 160 meters (1.8 MHz) to 17 meters (18 MHz). It does this through a USB interface and a 48kHz, 24-bit interface that is (or will shortly be) compatible with all the major SDR interfaces.
While the Peaberry SDR requires an amateur radio license to operate, we can’t wait to see what else will be coming to the software defined radio scene in the next year.
Thanks [Zach] for sending this one in.
