I believe it is just a channel marker. There is further information on this site: https://priyom.org/military-stations/russia/the-buzzer https://priyom.org/mili

I believe it is just a channel marker. There is further information on this site: https://priyom.org/military-stations/russia/the-buzzer https://priyom.org/military-stations/russia/the-buzzer They also tracked the signal using TDoA: https://priyom.org/blog/real-buzzer-site-found https://priyom.org/blog/real-buzzer-site-found!