UVB-76 The Buzzer Russian Military Radio Station

The Buzzer, widely known as UVB-76, was first spotted in the late 70’s and is known for its constant buzzing on 4625 kHz.  Although believed to be a radio anomaly or numbers station, it’s actually a Russian military station utilized by their western military district.

The buzzing sound has thought to be a mystery with no explanation.  However, it’s clear the buzzing is used as a channel marker and to keep the frequency clear so nobody will transmit over the sound.  It’s important that they reserve the frequency since it’s used for emergencies and important messages.  It can also be used for propagation measurements.

During the years of activity, the callsign has been changed many times. It was known first as UVB-76, although incorrectly.  The actual callsign was UZB-76 (УЗБ-76) and was correctly identified as this in many recordings. In 2010 it changed its callsign to MDZhB (МДЖБ), and in January 2016 its changed its callsign to ZhUOZ (ЖУОЗ).  It’s current callsign is NZhTI (НЖТИ).

Recording Sample

UVB-76 The Buzzer History and Callsign Changes

Since late December 2018, the station has again changed callsigns.  However, instead of single one, various new callsigns are used. The most used was ANVF, along with 2170, VZhCh, A1JZH, LNR4.  Other variations have been used with the ZhUOZ callsign not being fully abandoned.

The Buzzer Logbook Back Cover
Back cover of the logbook left behind at The Buzzer’s old location

Will the station return to singular callsign format remains a question and must be monitored further. In late December-January 2020 the station now switched to new callsign NZhTI.  New, infrequent callsigns are now TsZhAP, NVSB, ULVN, ODVR, UPVN, YeFUG.  The UVB DB project shows connections between currently used callsigns. (Viewable on PC only)

Although there have been numerous claims that The Buzzer works as a dead hand switch, this has never been the case.  The Dead Hand switch explanation has always been a myth, Russia has much more advanced nuclear systems such as the Perimeter Nuclear Defense System.  It has also never been used as a numbers station.

The station works as a communications center within the Western Military District that sends codes to corresponding military units and their outposts.  The buzzer transmits continuously throughout the day.  However due to the propagation issues in Western Europe, and especially in Northern America, it is problematic to receive during daylight time.

The sound of the station today has changed much since it was first discovered.  At one point The Buzzer used to change to a continuous buzz one minute before the hour, and until November 2010, its tone lasted slightly longer (about 0.8 seconds).  Now the buzzing tone lasts 1.25 seconds, with a 1.85 second pause.

The Buzzer also used to have the ENIGMA ID S28 although it wasn’t a numbers station, so it was later removed.  From February 18-26th, it used a temporary night frequency (assumed) on 3216 KHz.

The Buzzer Current Location

It’s Known, judging by Radio observation that at least two transmitter sites exist.  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, that servers as the main staff headquarters of the Western Military district in Moscow.  The Russian Military Districts

Former Location

UVB-76 old site in Povarovo, Moscow District
Former location of The Buzzer in Povarovo, Moscow

The first known location of UVB-76 was in Povarovo in the Moscow district at 56°5′0″N 37°6′37″E [3] However, since 2010 the site has been abandoned possibly due to the 2010 Russian military reform that combined the Leningrad military district and the Moscow military district into one Western military district.  A logbook left behind during the move shows the daily operations and work schedule of the station in 2005.

UVB-76 Voice Messages

Sometimes the marker drops and a live voice message is read. This is the stations primary use.  The usual voice message format is [Callsign] 58 151 [Codeword] 39 51 65 78 The callsign and the Codeword is spelled out in Russian phonetic alphabet.  (UVB-76 is the pre-movement callsign, the new callsign is MDZhB)

Russian Message Types
Received and printed messages are color-coded by their urgency: “Monolith” and “Air” – red hatching, “Rocket” – green, “Plane” – blue.

The specific format that the messages are sent in is known in Russian military terminology as “monolyth (монолит) messages”. They are scrambled messages sent live between the radio communication headquarters and subordinate military units. The purpose for these messages varies between testing the readiness of the unit, training, issuing warning messages and calls for mobilization.

In theory, the codebook lies in a sealed envelope in a special safe with instructions. Since different communication centers have different callsigns, codes and instructions for each military branch. The Russian intelligence agencies FSB, GRU and SVR don’t use such a system, instead it uses only numbers.  They use several different formats and special messages.

Monolyths are constantly changing, so the same monolyth could mean a different thing over time. It’s not a coded message but an order.  For instance the “BROMAL” – first recorded message could mean either full combat readiness or full withdrawal.

Messages with more than one code word are sometimes observed and messages with no end numbers after the code word are rarely spotted.  There has been observations of radio operator sending message incorrectly and then says “sboj” (error) that proves the message is read live.  There’s many Russian military message types used by the Buzzer and it’s counterparts.

The buzzer in the past has also been interfered with by other signals. in December of 2018, the buzzer was interrupted by what we believe was a Dutch pirate station playing Russian music and an air raid siren over the buzzer signal.  In March 2014 a Dutch HAM interrupted the buzzer. Note that March 18 2014 was the climax of the Crimean crisis which is when these interruptions were heard

The Buzzer Signal Harmonic EM Dissipation’s

There has been observations of Harmonic EM dissipation (when energy waves are getting weaker in equal steps) from the buzzers antenna. When buzzers frequency is tuned to CW mode the Harmonic EM dissipation can be heard. Every time the antenna transmits, it also inadvertently creates a harmonic rebounding EM.

The issues of the buzzer equipment create unintentional signal carriers. (Recording by Seth Weiner KC2UXD) The buzzer sound itself consists of a sequence of frequencies that are 2x of previous so considering they are nicely laid out.

They create temporary carriers that last only the time of the buzz itself. If the listener has a receiver that is tuned well enough, he can pick up in them the surrounding bandwidth. This phenomenon tends to occur more on antennas that are not well grounded.

Recreation of the Buzzer signal using FL Studio

The Buzzer Signal Waveform
The Buzzer signal has a sawtooth waveform. Its strong harmonics often serve the role of unintentional carriers, that give a glimpse of bandwidth in UVB-76 area.


Profile Summary

Country of Origin: Russia
Voice Summary: Male/Female live voice
Frequency: 4625 kHz/ 6998 kHz (since November 2015)
Mode: AM with suppressed LSB, voice messages can be in USB, or LSB
Counterpart Stations: The Squeaky Wheel, The Pip

More Photo’s of The Buzzer via Google Earth

1. Image of the Towers and Antennas
2. Incoming View From the Road
3. Possible 2nd Site at Naro-Fominsk
4. Someone walking into The Buzzer site
5. Main Control Building
6. Larger view with the gate in sight

Further Reading

UVB-76 The Buzzer Report articles summarize messages and show important events from 2012-2016:
2012 – 2013