There are many Software Defined Radios (SDRs) available, with a great deal of time and effort having gone in to their design. These are not those radios. We present four radios that we have designed using crude, novel, and sometimes ridiculous methods for transmitting and receiving signals.
The arrival of SDR allowed more hackers than ever to experiment with radio protocols, but we're still using hardware built by other people. In the time honored hacker tradition of rolling our own tools, we'll demonstrate four simple radios that can be home-built using commonly available parts for little to no cost.