County Bratislava Macra Na Feirme on X: "UVB-76 (The Buzzer) is a numbers station run by the russians since 1981. Its used to organize covert ops and military movements. Changes correspond to Rus. millitary action - like during 2014 crimea annex. Yesterday it was playing Gangam Style and sending spectrogram Troll Faces."
the buzz in the background is why it's called the buzzer, and over the years its changed in pitch and frequency. There used to be loads and loads of these numbers stations, normally used for espionage during the cold war era. youtube.com/watch?v=Wcv_cG…
Earlier today it was working as normal, a man's voice reading off a series of names and numbers interspersed with a signal (listen live here - right now just silence. youtube.com/watch?v=fUgzv-…)

