20 October 2026Own project · Radio networks & DIYOwn post

The Buzzer: listening live to Russia’s hum on 4625 kHz

Summary

For decades, a Russian shortwave channel has been humming around the clock on 4625 kHz, known as “The Buzzer” or by the misread callsign UVB-76. According to everything radio monitors have reconstructed, the hum belongs to a military command network that now and then sends short, coded voice messages. This post separates evidence from myth and shows how to follow the channel yourself on my receiver owrx.bk99.de.

UVB-76 erklärt: Was steckt hinter „The Buzzer“ auf 4625 kHz?Forgotten Adventure · 19:10Play video, loads the YouTube player

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A hum that never stops

Tune to 4625 kHz in the 64-metre band and you hear a rough buzz lasting a little over a second, then a pause of about a second, then the buzz again, roughly 21 to 34 times a minute, day and night. Radio monitors interpret it as a channel marker: it keeps the frequency occupied and shows the receiving stations that the channel is ready. No Russian regulation confirming this has been published, however.

The sound has not always been the same. A recording from January 1982 shows short, higher-pitched pulses, one from 1989 a high, slower tone; only around 1990 did the deep, almost foghorn-like buzz appear that gave the channel its nickname. Occasionally, conversations from the transmitter room can be heard in the background, which suggests the tone comes from a device in front of an open microphone.

The monitoring community lists the channel as S28 in the ENIGMA 2000 list. The most important specialist source is Priyom.org, where listeners have documented every message for years.

The name is a misreading

The station never said UVB-76. From the first known voice message on 24 December 1997, the identifier was УЗБ-76, i.e. UZB-76, which was soon written as UVB-76 in the West. UZB-76 was not the name of a transmitter either, but a collective callsign for the receivers in the network. Russian listeners call it “Жужжалка”, the buzzer.

The collective callsign has changed several times: MDZhB from September 2010, ZhUOZ from late 2015, ANVF from March 2019 and NZhTI since late 2020. According to Priyom, the channel addresses its messages to 25 different recipient callsigns in 2026.

What is sent

A woman or a man reads the voice messages live in Russian. Most follow the format monitors call “Monolith”: one or more four-character callsigns, each read twice, then a group of digits, and finally one or more code words with eight digits each. A typical example:

NZhTI NZhTI 34 511 GOLOSOK 80 17 81 54

The code word, here “Golosok” (little voice), is not meant literally: without the matching keys and tables, what a message means to its recipient remains unknown. The structure, by contrast, is well understood. The name fits Soviet military radio practice, where “Monolit” ranked as the highest urgency level after Samolyot, Raketa and Vostok; that alone does not prove a direct link to the Buzzer.

Most messages arrive on weekdays during daytime Moscow time (UTC+3). Two rarer formats, “Uzor” and pure command messages (“Объявлена команда”, command announced), have not appeared on this channel since 2022, according to Priyom.

Not a transmitter but a network

For a long time, Povarovo north-west of Moscow was considered the site; monitors attribute the now abandoned facility there to the channel until 2010. September 2010 brought the clearest break: a new collective callsign, tests and interruptions, at the same time as Russia merged the Moscow and Leningrad military districts into the new Western Military District. There is no official confirmation of the connection.

Since then, a network rather than a single transmitter has emerged: according to Priyom, it is controlled from a communications hub near Agalatovo north of Saint Petersburg and transmitted from changing shortwave sites, at times including Kerro north of Saint Petersburg and Naro-Fominsk south-west of Moscow. After a presidential decree of 26 February 2024 re-established the Moscow and Leningrad districts, monitors now attribute the Buzzer to the Leningrad Military District.

Myths: Dead Hand and research transmitter

The most persistent claim is that the Buzzer belongs to the Soviet backup command system Perimetr, known in the West as “Dead Hand”, and that its silence would trigger a nuclear counter-strike. Perimetr was real, but there is no documented link to the 4625 kHz network. Practice alone argues against it: the channel has failed, been serviced and been switched off many times without anything happening.

A second theory sees a research transmitter. A publication from the Borok geophysical observatory does describe Doppler measurements of the ionosphere using a stable signal on 4.625 MHz. That only shows an existing signal can be used for measurements, not that the Buzzer is operated for that purpose.

There is still plenty going on on the frequency: in September 2010, Tchaikovsky’s Swan Lake briefly replaced the buzz, in January 2022 images appeared that were only visible in the waterfall display, and pirates keep playing music over it. Such interludes usually do not come from the operator.

Listening yourself via owrx.bk99.de

My public receiver owrx.bk99.de has a dedicated profile for it. Here is how:

Open owrx.bk99.de and click “Start OpenWebRX+” so that the browser may play audio.
In the receiver panel on the right, select the profile “4,625MHz - UVB-76 Buzzer (AM)” in the drop-down menu.
Tune to 4625.0 kHz and select USB. With a carrier, the Buzzer also sounds fine in AM, but at times it transmits without a carrier, and then only USB works.

The direct link only sets frequency and mode if the Buzzer profile is already active. The receiver is a single SDR stick with 38 profiles and at most four simultaneous listeners; switching the profile switches it for everyone. The client counter at the bottom of the window shows whether someone else is listening.

During the day, the lower ionosphere absorbs most shortwave around 4.6 MHz. In Germany, the Buzzer is best heard from the evening on, stays clear through the night and fades around sunrise. From Meerane it is about 1,500 kilometres in a straight line to Saint Petersburg and about 1,700 to the Moscow area. Voice messages, on the other hand, mostly come during the day; to get both, try late afternoon in the darker months.

Numbers at a glance

Frequency 4625 kHz, wavelength 64.8 m, today mostly upper sideband (USB), sometimes with and sometimes without a carrier.
Buzz about 1.2 seconds, pause 1 to 1.3 seconds, 21 to 34 tones per minute.
Oldest surviving recording of the marker: January 1982; first known voice message: 24 December 1997.
Collective callsign since late 2020: NZhTI; according to Priyom, 25 recipient callsigns in 2026.
Distance from Meerane to Saint Petersburg about 1,500 km, to the Moscow area about 1,700 km.

References

Remarks

The embedded video “UVB-76 erklärt” by Forgotten Adventure (series Kalter Krieg Kompakt, 18 October 2026, in German) carefully separates evidence from speculation and was an important basis for this post.
I run the receiver owrx.bk99.de with OpenWebRX+ (version 1.2.126 on 20 October 2026). It is a shared device: please do not leave settings changed after listening; others use, for example, the ADS-B profile for aircraft data.
Information on operator, sites and assignment is based on decades of radio monitoring, not on official Russian statements. The German UTDX wiki was last edited in 2021 and partly shows older information.

Listen to the Buzzer on owrx.bk99.de