See also Melissa Elliott's Defcon 2012 talk "Exploring Unintentional Radio Emissions": http://www.youtube.com/watch?v=5N1C3WB8c0o (I actually bought a chea

See also Melissa Elliott's Defcon 2012 talk "Exploring Unintentional Radio Emissions": http://www.youtube.com/watch?v=5N1C3WB8c0o (I actually bought a cheap SDR dongle after watching it, to see what I could pick up. So far I've found that the antenna it comes with makes tuning into FM radio difficult :/, and when I went to use it to do some investigation about WiFi signal traffic I was reminded they have a limited range on the spectrum...)