HackRF is an open source hardware project to build a Software Defined Radio (SDR) peripheral.
SDR is the application of Digital Signal Processing to radio waveforms. It is similar to the software-based digital audio techniques that became popular a couple of decades ago. Just as a sound card in a computer digitizes audio waveforms, a software radio peripheral digitizes radio waveforms. It's like a very fast sound card with the speaker and microphone replaced by an antenna. A single software radio platform can be used to implement virtually any wireless technology (Bluetooth, ZigBee, cellular technologies, FM radio, etc.).
Digital audio capabilities in general purpose computers enabled a revolution in the sound and music industries with advances such as hard disk recording and MP3 file sharing. Today's computers are fast enough to process radio waveforms in similar ways, and the radio communications industry is going through the same sorts of changes. One critical advance is finally taking place now, and that is the availability of low cost tools enabling anyone to take part in the revolution.
Wide Operating Frequency Range
HackRF operates from 30 MHz to 6 GHz, a wider range than any SDR peripheral available today. This range includes the frequencies used by most of the digital radio systems on Earth. It can operate at even lower frequencies in the MF and HF bands when paired with the Ham It Up RF upconverter.
Transceiver
HackRF can be used to transmit or receive radio signals. It operates in half-duplex mode: it can transmit or receive but can't do both at the same time. However, full-duplex operation is possible if you use two HackRF devices.
Portable
You don't have to carry an external power supply with you when taking HackRF on the road because it is powered by USB. It is small enough to fit easily into a typical laptop bag. Your HackRF will be slightly smaller than the beta unit pictured above and will protected by a full enclosure.
HackRF is designed primarily for use with a USB-attached host computer, but it can also be used for stand-alone applications with Jared's HackRF PortaPack, an add-on that gives HackRF an LCD screen, directional buttons, and audio ports.
Low Cost
HackRF was designed to be the most widely useful SDR peripheral that can be manufactured at a low cost. The estimated future retail price of HackRF is $300, but you can get one for even less by backing the Kickstarter project today.
Wideband
The maximum bandwidth of HackRF is 20 MHz, about 10 times the bandwidth of TV tuner dongles popular for SDR. That means that HackRF could be used for high speed digital radio applications such as LTE or 802.11g.
Open Source
The most important goal of the HackRF project is to produce an open source design for a widely useful SDR peripheral. All hardware designs and software source code are available under an open source license. The hardware designs are produced in KiCad, an open source electronic design automation tool. You can download the Jawbreaker (HackRF beta) design and build your own HackRF today!
Full link : http://www.kickstarter.com/projects/mossmann/hackrf-an-open-source-sdr-platform