The clue to the function is the maintained frequency of 4625 khz. The buzzer doesn't broadcast higher up the HF frequency band. If it was
transmitting on various frequencies then it would be fulfilling a function in relation to that radio propagation. It is specific to the Moscow Oblast
region.
You can see from Russian radio scanner forum that some of the Russian conscripts knew of the Buzzer being set up on their radios. The radio receivers
were located in military bases in the Moscow Defence Region and fulfilled an emergency communications system.
www.radioscanner.ru...
The UK used a similar system known as HANDEL for its Civil Defence warning system. The only difference was that instead of shortwave the system was
relayed over the national phone lines. The problem with the phone line system was that it obvioulsy relied heavily on telegraph poles and lines. The
Russians obviously built a more robust system to function post attack.
My theory is that the Russian Buzzer is the Civil Defence network system for the Moscow region. The use of HF radio would mean that it would function
during the electro magnetic pulse wave generated in a nuclear strike. This is one of the reasons that the Russians still use Morse Code on their
networks and still able to get through in an EMP environment.
www.ringbell.co.uk...
You can see the HANDEL system in operation on the following video. See 05:00 point on video from the 1970s. The UK disbanded the specific nuclear
warning Civil Defence network in the early 1990s.
www.youtube.com...
A carrier is maintained on the broadcast (regular ticking) until a command and control message is sent.
www.youtube.com...
During the Soviet era the Civil Defence network was huge and a played a vital part in defence of Russia. It required command and control and so does
the modern day equivilant.
en.wikipedia.org...