This is a couple months old, but still a great discovery. Using an inexpensive USB TV Tuner, you have a Software-Defined Radio (SDR) capable of tuning anywhere from 64-1700 MHz, and in some cases beyond that.
I recently purchased a dongle on eBay for about $20 and got the setup working on a Windows machine. However, as this article points out, there is now a source block for GNU Radio that allows you to decode just about any modulation you'd like, from P25 digital voice, to trunking data, to GPS or ACARS data. I don't have a Linux machine handy that is capable of running GNU Radio, so for now all my experiments have been on Windows with HDSDR. This program demodulates FM, AM, SSB, CW, and DRM.
One thing to note is that these dongles, at least with their included antennas, are pretty poor at receiving anything but moderately strong signals. I just ordered an antenna adapter so I can use SMA antennas with the device. We'll see how the reception improves.
[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.
via Hack a Day