When I was a wee nipper the Cold War was at its peak and I remember many nights, even days, playing with my grand parents radios. Since they had MW, SW, AM etc etc bands. When my folks upgraded their radio, it too had the many radio bands, I would hunt for the more obscure number station. I had no clue to what the heck it all was about, only that it was something secret and very mysterious, and by the look of it the internet still don't know what it is all about either.
This is a rather good article -
http://www.bbc.co.uk/news/magazine-24910397Wiki -
http://en.wikipedia.org/wiki/Numbers_stationJust played some of the recordings and it gave me a spooky goose bumpy shiver, ah good old days
"83912 83912 10080 10080 46543 46543 - 257 257 143 143 - 00000"