One question tho, are those still broadcasted? And why would they even be?
most likely not
they were commonly used during warfare as means of transporting messages to allies without the enemy realising what you were telling them
(the germans had terrible code creators, fyi)
among the most infamous were the russian stations during the cold war, which would play music as to appear as a regular station
they'd broadcast their number code during specific times and play creepy music the rest of the time to avoid detection
