In the middle of a Russian swamp lies an abandoned location known as “MDZhB,” a mysterious radio station that has been broadcasting a monotonous tone since 1982. The purpose and origin of the station remain unknown, sparking numerous theories and capturing the attention of conspiracy theorists. The frequency, 4625 kHz, is believed to belong to the Russian military, although they have never claimed it. Some theories suggest the station is meant to communicate with submarines or serve as a “Dead Hand” signal for nuclear retaliation. The station’s enigmatic nature and online following have earned it the nickname “the Buzzer.”
https://www.bbc.com/future/article/20170801-the-ghostly-radio-station-that-no-one-claims-to-run