If anyone has a USB DVB-T/RTL-SDR adapter that is gathering dust, and you like aeroplanes, I suggest looking into the dump1090 software. Or more specifically use the package here for the RPi -
http://feed.flightradar24.com/raspberry-pi/ - and start tracking local aeroplanes and submitting the data to Flight Radar 24. If you submit data you get a free Premium account.
Even with the cheap desktop antenna you can get a range of about 70 miles in each direction.
I was running it on my linux server but that's under the stairs so reception wasn't great, though in the south direction it was picking up planes as far as Birmingham. My East-West range is poor because I'm in a terraced house.
It's now running on a Raspberry Pi and I've started to build a couple of antennas which are designed for the correct wavelength so see if I can get a better range. They are best placed outside with a decent view of the sky. My current antenna is a tin can cut in half with a wire sticking out of the top! Even with small homemade antennas you can get upwards of 200 miles range.
I must admit it gets a bit obsessive seeing what aeroplanes I'm tracking.
If anyone wants a look at my live map -
http://fr24.antthomas.co.ukEDITED: 30 May 2015 18:34 by ANT_THOMAS