(sometimes referred to as UZB-76, but recently MDZhB) is the call sign of a shortwave radio station that usually broadcasts on the frequency 4625 kHz (AM suppressed lower sideband). It is known among radio listeners by the nickname The Buzzer. It features a short, monotonous buzz tone repeating at a rate of approximately 25 tones per minute, for 24 hours per day. The station has been observed since around 1982. On rare occasions, the buzzer signal is interrupted and a voice transmission in Russian takes place. Despite much speculation, the actual purpose of this station remains unknown to the public.
Normal transmissionOne minute before the hour, the repeating tone was previously replaced by a continuous, uninterrupted alternating tone, which continued for one minute until the short repeating buzz resumed, although this no longer occurs.
The Buzzer has apparently been broadcasting since at least 1982 as a repeating two-second pip, changing to a buzzer in early 1990. It briefly changed to a higher tone of longer duration (approximately 20 tones per minute) on January 16, 2003, but it has since reverted to the previous tone pattern.
MalfunctionsFrequently, distant conversations and other background noises can be heard behind the buzzer, suggesting that the buzz tones come from a device placed behind a live and constantly open microphone (rather than a recording or automated sound being fed through playback equipment), or that a microphone may have been turned on accidentally.One such occasion was on November 3, 2001, when a conversation in Russian was heard:"Я — 143. Не получаю генератор." "Идёт такая работа от аппаратной." ("I am 143. Not receiving the generator (oscillator)." "That stuff comes from hardware room.").
Voice messages & other soundsVoice messages from UVB-76 were very rare until a sudden spate of activity in the latter half of 2010.They are usually given in Russian by a live voice and repeated. At least seven such messages have been heard in over twenty years of (non-continuous) observation.Some examples of such messages include:
- At 2100 UTC on December 24, 1997: "Ya UVB-76, Ya UVB-76. 180 08 BROMAL 74 27 99 14. Boris, Roman, Olga, Mikhail, Anna, Larisa. 7 4 2 7 9 9 1 4."
- At 1335 UTC on August 23, 2010: "UVB-76, UVB-76. 93 882 NAIMINA 74 14 35 74" (Recording of August 23rd transmission)
Location and functionAlthough there is much speculation about the transmitter site, the station's transmitter is believed to be located near Povarovo, Russia at which is about halfway between Zelenograd and Solnechnogorsk and 40 kilometres (25 mi) northwest of Moscow, near the village of Lozhki. The location and callsign were unknown until the first voice broadcast of 1997.
The purpose of UVB-76 has not been confirmed by government or broadcast officials. However the former Minister of Communications and Informatics of the Republic of Lithuania has written that the purpose of the voice messages is to confirm that operators at receiving stations are alert.