After capturing Vyiborg, there were sudden explosions without reason. After finding one of these bombs, Finnish pioneers realized that the fuze of the bomb was activated by russian radio: when they played a certain chord of three notes, the strings in fuze start vibrating and finally would close the circuit blowing up the bomb.
To counter this, finnish radio and some frontline radiotransmitters started playing this fast Polka song on a loop non stop for weeks. They thought that this fast song would not hold the required three notes long enough, so the bombs wouldn't go off. After starting the transmissions there were no further explosions.
https://fi.wikipedia.org/wiki/Viipurin_radiomiinat
Here's the wikipedia on it, sadly it's in finnish. True story, tho

And here's the song for you all to relive those wonderful months of late summer 1941. Talk about repetitive playlists on radio!!