Duga was a Soviet OTHR (Over The Horizon Radar) that was known for its constant tapping noise, and because of this was nicknamed “The Russian Woodpecker”. This radar was part of a system that was used for early detection of missiles and was active from July 1976 until December 1989. Since then, it has now been retired. Over time, claims of it being used for mind control and weather experiments emerged, however this was never the case. There are two Duga radars, one is located at Chornobyl and Chernihiv in Northern Ukraine the other one is in Khabarovsk Krai in Russian Far East.
The experimental Duga (coded designation 5H77) was built outside Mykolaiv in Ukraine, but this array has been demolished and is no longer there.
Duga-1 (Object Chernobyl-1) was built near two military towns and Chenobyl-1 Liubech-1 close to Pripyat and Chernihiv and begun regular transmissions on 1985, however was forced to cease work after Chornobyl Nuclear Power plant accident.
Duga-2 was built was restored around 2002 since it had sustained fire damage. It ceased transmissions on 1989. The Duga-1 radars had a much higher power output than the other the other 2, and was more noticeable than the others because of this.
CIA first became aware of Soviet plans to build the radar on 1970 and made photographic reconnaissance around the area. The declassified documents shows that CIA found “”a standart FIX 24 HF/DF antenna” and support area of “at least ten buildings”. Note that town of Pripyat was established in 1970 and on 1972 the Chernobyl Power Plant building had begun. CIA was also aware of first facility in Mykolaiv and made detailed report on 1969,
Although there were three Duga type radars, designation Duga-3 never existed as the most known radar located in Chernobyl area was called Duga-1 or Object Chernobyl.
Spectrum image of the 10 Hz pulses
The woodpecker was known to use three different repetitive rates, 10 Hz, 16 Hz, and 20 Hz. The 10 Hz rate was used more often than the other two. The powerful transmitter enabled Duga-3 to be heard from around the world. So the “woodpecker” sound created by it interfered with many other shortwave stations, and there were even some products created to counter this.
The Duga-3 arrays are still standing, and are accessible to the public.