[eatmychild]

There's a radio which belongs to somebody else that used to play a burst of static every 5 seconds on 1450 - 1500 KHZ on AM, it was quite relaxing so I had it going sometimes when doing work. One time when listening to it it changed suddenly and started making really loud bursts of static and white noise, and then started playing the noise in rhythms. It made the occasional high pitch 'woop' and whine. I recorded some of it so I could possibly upload it sometime.

And a classic listen can be had on LW 148. Regular series of beeps.