UVB-76, the mystery!

UVB-76, the mystery!
Long time I did not see anyone commenting about it here, so I will put it on the agenda again. As I am too lazy I'll get the wikipedia text only to those who have never heard, knowing what it is:
UVB-76 is a radio station shortwave, which usually transmits at a frequency of 4625 kHz. It is known among radio listeners by the nickname The Buzzer. It has a small, drab? signal repeating at an approximate rate of 25 tons per hour for 24 hours a day. The station has been observed since about 1982. [1] On rare occasions, the alarm signal is interrupted and a voice transmission in Russian takes place. Only three or four such events were noted since 1982.
There is much speculation, however, the real aim this season is still unknown.
The station transmits a buzzing sound that lasts 0.8 second, pausing for 1-1.3 seconds and repeating minuto.Um 21-34 times per minute before the hour, the repeating step is replaced by a step continuous, which continues for a minute until the repeat tone back to play. [citation needed] Between 07:00 and 07:50 GMT, the station transmits with low power consumption, while maintaining the transmitter apparently occurs.
The UVB-76 was transmitted at least since 1982 as repetitive "pip" two seconds, changing to a buzzer in early 1990. She was briefly changed to a higher pitch and of longer duration (about 20 tons per minute) January 16, 2003, although this sound has been reverted to the tone pattern anterior.Freqüentemente, distant conversations and other background noises can be heard by the station: this suggests that the device is moved behind a live microphone and constantly open (instead of a sound recording being fed through automated or reproducing equipment) or a microphone may have been accidentally. One such occasion was on November 3rd, 2001, when a conversation in Russian was heard:
Often distant conversations and other background noises can be heard by the station: this suggests that the device is moved behind a live microphone and constantly open (instead of a sound recording or automated being fed through playback equipment) or a microphone may have been accidentally turned on. One such occasion was on November 3rd, 2001, when a conversation in Russian was heard: "Я - 143. Не получаю генератор". "Идёт такая работа от аппаратной". ("I am the 143. I do not get the oscillator (generator)." "That's what the operating room are sending." Or "These are the operations orders.")

https://www.youtube.com/watch?v=-2EKWgTNEYU&feature=player_embedded
recording signal