BTW, I thought of it when watching the video -- I used to have a cats-whisker radio. OK, it wasn't actually from a cat, it was a piece of wire about the same thickness, but thta's what it was called. You fiddled it against a piece of crystal until it made the right sort of contact to receive a signal, and then kept very still so that it wasn't disturbed, and listened on headphones. I think it belonged to my grandfather originally (or possibly great-grandfather). Back in the good old days of the BBC Home Service...