UVB 76 Radio Signal

UVB-76, also known as '"the Buzzer", is the nickname given by radio listeners to a shortwave radio station that broadcasts on the frequency 4625 kHz. It broadcasts a short, monotonous  buzz tone , repeating at a rate of approximately 25 tones per minute, for 24 hours per day.On very rare occasions, the buzzer signal is interrupted and a voice transmission in Russian takes place. The first reports were made of a station on this frequency in 1982. Its origins have been traced to Russia, and although several theories with varying degrees of plausibility exist, its actual purpose has never been officially confirmed and remains a source of speculation.

The station transmits using AM with a suppressed lower sideband (R3E), but it has also used full double-sideband AM (A3E). The signal consists of a buzzing sound that lasts 1.2 seconds, pausing for 1–1.3 seconds, and repeating 21–34 times per minute. Until November 2010, the buzz tones lasted approximately 0.8 seconds each. One 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 since June 2010.

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.

On rare occasions, the buzzing sound is interrupted and a voice message is broadcast. These messages are usually given in Russian by a live voice, and follow a fixed format.

Until 2010, voice messages were thought to be very rare. An example 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."

During 2010, listeners reported increased activity of the station, which spurred on further monitoring and allowed listeners to "catch" more of the messages which would have otherwise gone unnoticed. On June 5, 2010, UVB-76 went silent for approximately 24 hours, resuming the normal buzzing pattern on the morning of June 6. At 1335 UTC on August 23, 2010, a voice message was broadcast:

"UVB-76, UVB-76. 93 882 NAIMINA 74 14 35 74"

A spectrum for UVB-76 showing the suppressed lower sideband.

It is also speculated that the voice messages are some sort of Russian military communications, and that the buzzing sound is merely a "channel marker" used to keep the frequency occupied, thereby making it unattractive for other potential users.There are two other Russian stations that follow a similar format, nicknamed "The Pip" and "The Squeaky Wheel". Like the Buzzer, these stations transmit a signature sound that is repeated constantly, but is occasionally interrupted to relay coded voice messages.

There is speculation published in the Russian Journal of Earth Sciences which describes an observatory measuring changes in the ionosphere by broadcasting a signal at 4625 kHz, the same as the Buzzer.The purpose of the station has not been confirmed by government or broadcast officials. However, the former Minister of Communications and Informatics of the Republic of Lithuania Rimantas Pleikys has written that the purpose of the voice messages is to confirm that operators at receiving stations are alert. Other claims are that the broadcast is constantly being listened to by military commissariats.

The former transmitter was located near Povarovo, Russia at 56°5′0″N 37°6′37″E 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 known voice broadcast of 1997. In September 2010, the station's transmitter was moved near the town of Pskov. This may have been due to a reorganization of the Russian military. In 2011 a group of urban explorers explored the abandoned buildings at Povarovo. They claim that it is an abandoned military base. A radio log record was found, confirming the operation of a transmitter at 4625 kHz

Truth about UVB 76