The Secret World of Number Stations

Aug 9, 2017 0 comments

Back in the days of Cold War espionage, foreign intelligence agencies used to communicate with agents on the field via shortwave radio. Radio transmitters placed at secret locations around the world would broadcast coded messages usually in the form of an automated voice reciting a string of numbers or letters. The message often began with a melody, or a set of beeps, or a buzz, followed by the actual coded message read aloud by a voice. Anyone with a radio receiver tuned into that frequency could hear it, but only the intended recipient with proper decoding instructions could decipher the message. For the rest of the listeners, they were just a string of random numbers. Ham radio operators, who frequently stumbled upon these secretive transmissions, called them “number stations”.


Photo credit: k'nash/Flickr

One of the first known use of number stations was during the First World War, and one of the first civilians to discover them was Anton Habsburg, the Archduke of Austria and Prince of Tuscany, who was a young teenager at that time. Habsburg would write down the coded message from enemy stations, and on his way to school dutifully hand the piece of paper to the war office. The war office, of course, had its own listening post but once when the receiving stations at the war office couldn’t operate due to heavy frost, they used Hasburg’s copy of the message.

The use of number stations rose during the Cold War era. The British Secret Intelligence Service used to operate one out of Bletchley Park in the mid-1970s, and later from RAF Akrotiri in Cyprus. Amateur radio operators called it the “Lincolnshire Poacher”, because the station used melodies from the English folk song "The Lincolnshire Poacher" as an interval signal. The former state of Czechoslovakia also used numbers stations for espionage, as acknowledged by the Czech Ministry of the Interior and the Swedish Security Service.

Times have changed and technology has made tremendous advances in communications and cryptography. Yet, there is evidence that this seemingly old-fashioned method of communication might still be used today, and for good reasons. The system is completely secure and anonymous. The recipient of the message can be almost anywhere in the world, and can receive instructions without being traced. All they need is a shortwave radio.

One of the most famous number station that’s been active since at least the 1970s, is the UVB-76, also known as “the Buzzer”. Broadcasting at 4625 kHz, it consist of almost nothing but a strange, repetitive buzzing tone a little more than a second in length and repeating about twenty-thirty times per minute. Sometimes, the buzzer signal is interrupted by a Russian voice reading out a brief sequences of numbers and words, and occasionally a few Russian names such as “Nikolai, Anna, Ivan, Mikhail” and so on.

A typical message looks like this:

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

This one was received on December 24, 1997.

The buzzing tone is not generated internally, but are transmitted from a device placed behind a live and constantly open microphone. Frequently, the microphone would pick up distant conversations and other background noises behind the buzzer. On November 3, 2001, a conversation in Russian was clearly 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.").

Followers of the signal had previously triangulated the location of the transmitter to a place called Povarovo, situated about 30 km from Moscow. But in 2010, the transmitter was moved to the nearby city of Saint Petersburg. It’s current location is believed to be Naro Fominsk, situated about 70 km from Moscow.

In 2011 a group of urban explorers actually located the abandoned military base in Povarovo where UVB-76’s transmitter is supposed to have been. A radio log record was found, confirming the operation of a transmitter at 4625 kHz.


The partly disembodied military unit of UVB-76 radio station as discovered in a bunker in Povarovo. Photo credit: kspzel

As intriguing as it is, the UVB-76 isn’t the only active number station in existence. There are dozens more transmitting in various languages such as English, Polish, German, Russian and Chinese. All you need to do is get yourself a short wave radio, tune into the station and start listening.

Sources: BBC / Wikipedia / Wired /


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