Occasionally (because, I guess, they were radio stations), they'd also play music, usually something also anonymous, and repetitious. (When I was a kid, learning the magic of radio, my dad's short wave had a station playing the opening bars of the Star Spangled Banner, over and over. Now that I think of it, that might have been a numbers station.) (Or else, the record was just stuck.)
The phenomenal Internet Archive has a selection of these stations. I went into that scary shortwave world and collected a brief pastiche of weird music (intentional or not.)
