OMD actually did a sample of Radio Prague’s Interval Signal on the album “Dazzle Ships”
https://www.youtube.com/watch?v=9oWSJpIHhYk
We’re probably among a few who know what an interval signal is.
A little radio trivia for those who are not quite bored enough yet: For shortwave broadcasts, an interval signal was a repetitive loop often of music or musical notes given a few minutes before the broadcast officially began - this was so listeners could find and tune in the station on their old analog receivers.
Oh wow - that brings back memories of the Cold War days.