Duga-3 ("duga" means "arc") or "Steel Yard" was a Soviet experimental over-the-horizon radar (OTH) system. It was developed for the Soviet ABM early-warning network. The system operated from 1976 to 1989.Two stations of Duga-3 were installed: a western system around Chernobyl and an eastern system in Siberia, near Komsomolsk-na-Amure.The transmitter for the eastern Duga-3 was located approximately 30 km SE of Komsomolsk-na-Amure.