The Duga (meaning arc in Russian) was a Soviet over-the-horizon radar (OTH) system used as part of the Soviet missile defense early-warning radar network.
There were 3 Duga systems built, the first near Chernihiv (in the Ukrainian SSR) , the second in the remote woods about 10 kilometers south from Chernobyl, and the third in eastern Siberia.
The Duga systems were extremely powerful, over 10 MW in some cases, and broadcast in the shortwave radio bands.
Being part of the Soviet military network, their existence was kept extremely secret. The Duga station in Chenobyl was built near the city of Pripyat: the zone around the Radar was entirely off limits and was known as Chernobyl 2, but as many other Soviet sites of military relevance wasn’t to be found on any official maps.
While broadcasting, the Duga radars produced a sharp, repetitive tapping noise at 10 Hz repetition rate, which led to it being nicknamed by Western shortwave listeners the Russian Woodpecker.
The unclaimed signal was a source for much speculation, giving rise to theories such as Soviet mind control and weather control experiments, before Western experts realized it to be an over-the-horizon radar system.
The radars were in reality used for monitoring rocket launches and submarine movements, both in the Far East and from the United States. The main purpose of the whole project was actually to detect American Nuclear Missiles being launched towards the USSR.
They were huge structures. The metal construction of the Duga radar in proximity of Chernobyl was composed of two parts:
- a low-frequency antenna with a height of 135 – 150 meters and length of almost 500 meters
- a high-frequency antenna with a height of 100 meters and length of 250 meters.
The Duga station in Chernobyl, whose construction started simultaneously with the Chernobyl nuclear power plant, also included a small town close to the garrison of the radar station for families. The garrison held about one thousand people, as reports an article on the Duga-2 radar by Chernobyl Welcome, a tour operator offering guided tours in Prypiat and in the Chernobyl area.
Its functioning was interrupted because of the accident at the Chernobyl nuclear power plant on 26th April 1986 and the the system was partially preserved until the end of 1987, and then abandoned since then.
At the moment there are only antennas left, while the computer center was dismantled. Everything else has been transferred or stolen.