Since dekades of years some Russian mystery transmitters can be heard all over Europe, sometimes even in the United States. All are operating continously as channel markers and rarely transmit voice messages. They seem to work independently.
Their purpose remain - despite many investigations - in the dark, although most agree, they are of Military origin. Are they emergency or backup systems, do they belong together or are they even part of the alarm network of the Strategic Nuclear Forces ? Others believe, their role might simply be in connection with the Recruitment Authorities of Moscow Military District.
Some utility DXers have specialised and report regularly their new findings, the best place to look after is Numbers & Oddities: http://home.luna.nl/~ary/
The Buzzer, callsign UVB-76, is a strong station on 4625 kHz, audible daily from late afternoon until dawn and transmitting a buzzing sound in short, regular intervals. You may however - with patience - hear short voice transmissions in USB modulation and in plain Russian. If they are not of technical content for maintenance, they do have the same message format as the Russian Strategic Flash Messages in Morse Code described here: Networks of the CIS Navy . Now, that is interesting and indicates, this station is an important part of the Armed Forces.
Until 2010 voice messages were only heard a few each year. Then the transmitter was off for months and came back with many more messages, apparently from another transmitter site and with a second callsign MDZhB, which since then is in use alternatively.
The actual transmitter site is not clear yet, RDF from several countries point towards the region of Pskov. Until 2010 it is firmly believed UVB-76's home was in a forest near Povarovo, N of Moscow, as part of the Mil Radio Center Nr. 141.
It is well possible, that the transfer of the station into the Leningrad Mil District has to do with the new structure of the Armed Forces since 2010.
The story of The Pip is not a long one. The station uses 5448 kHz (day) and 3756 kHz (night) for its transmission: pip-pip-pip ...
A few cases of short voice communications have been reported in all these years and that's about all we know. The location of the transmitter is unknown, in Central Europe the signal is reasonably strong.
For many years and until 2009 this station sounded exactly like a - squeaky wheel. Actually there are two different tones in a short sequence repeated. The frequencies are 5473.9 kHz (day) and 3828.9 kHz (night). Several times voice messages in the format of Strategic Flash Messages have been reported.
The transmitter site is unknown, the signalstrength is not very good in Central Europe and the station sometimes even might disappear for days in the noise.