[sorenjan]

Can we take a moment and reflect on the fact that all of this data is freely available to anyone? I can sit in front of my computer, or anywhere with my phone, and follow planes around the world with an accuracy of a few meters, and replay the data at a later date.

The various flight trackers all use thousands of receivers around the world, and most of them probably use the same kind of SDR chip that was originally designed for USB TV and radio receivers.

http://rtlsdr.org/#history_and_discovery_of_rtlsdr