The most profound change in radio technology in 100 years is happening now. Radios are transforming from the spaghetti of mind-bogglingly complex electronics into simple (but very fast) digitisers, and all the hard work is being done in software. Hence the name Software Defined Radio (SDR).

Gnu Radio is a simple entry point to the world of SDR, and allows you to quickly prototype different kinds of radios by dragging, dropping, and connecting functional blocks.

I'll demonstrate, and show that it's surprising what you can do with a radio receiver.