The Buzzer (ZhUOZ MDZhB UZB76)

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The Buzzer (ZhUOZ MDZhB UZB76)
Frequencies 4.625 MHz,6.998 MHz
Frequency Range 4.625 MHz - 6.998 MHz
Mode AM
Modulation USB
Bandwidth 2.8 kHz
Location Russia
Short Description The Buzzer, call-sign ZhUOZ (formerly MDZhB and UZB76), is a Russian based military station that occasionally broadcasts Monolit format messages in Russian. Its trademark buzzer is constantly transmitted while there is no message to broadcast.
I/Q Raw Recording
Audio Sample

The Buzzer, call-sign ЖУОЗ (ZhUOZ), nicknamed Жужжалка, formerly known by its previous callsigns МДЖБ (MDZhB) and УЗБ76 (UZB76), is a Russian-based military station that frequently broadcasts Monolit format messages in Russian. Its official name is actually вулкан (Vulkan, Volcano in English). Its trademark buzzer is constantly transmitted while there is no message to broadcast. Active since the late 1970s.

ZhUOZ is an analogue Upper Side Band voice signal. It has an active carrier at 4625 kHzKiloHertz (kHz) 10^3 Hz. It is believed that the buzzer is not directly modulated but actually recorded by a active microphone, as there have been reports of hearing background chatter while the buzzer was on.


On September 7, 2010, The Buzzer changed its callsign from УЗБ76 (UZB76) to МДЖБ (MDZhB)

Since October 15, 2015, The Buzzer has been seen transmitting in parallel on a new frequency 6998 kHzKiloHertz (kHz) 10^3 Hz, while still transmitting on 4625 kHzKiloHertz (kHz) 10^3 Hz.

Since December 28, 2015, The Buzzer has changed its call-sign to ЖУОЗ (ZhUOZ).


At least two transmitters exist for MDZhB. One is confirmed to be at 60°18’40.1″N 30°16’40.5″E where it sends radio relay and phone lines directly from Moscow via St. Petersburg's command hub on Palace Square.

The other site is claimed to be located at Naro-Fominsk, Moscow district at 55°25’35″N 36°42’33″E where the 69th communications center is located, which serves as the main staff headquarters of the Western Military district in Moscow.


The Buzzer:

Example of Voice Messages on ZhUOZ:

Buzzer Malfunctions (Submitted March 23, 2017 and September 15, 2019):

Video Examples[edit]

Media Documentation[edit]

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