Anyway, there are more creative methods to insert coded messages in radio shows, for example, some years ago, the italian police confiscated a commercial radio in Naple. That radio was controlled by a mafia family and used to send message to the inmates of Poggioreale prison. They used fake "inscription" related to the songs transmitted:
But this isn't a new idea, there are a lot of pop songs with embedded morse code messages, for example, this Slipknots' song:
http://en.wikipedia.org/wiki/Before_I_Forget_%28song%29
A tutorial:
http://homepage.ntlworld.com/dmitrismirnov/MorseMusic.html
Anyway, there are more creative methods to insert coded messages in radio shows, for example, some years ago, the italian police confiscated a commercial radio in Naple. That radio was controlled by a mafia family and used to send message to the inmates of Poggioreale prison. They used fake "inscription" related to the songs transmitted:
http://www.corriere.it/Primo_Piano/Cronache/2007/06_Giugno/1...