The Dunay-3U (Russian: Дунай-3У, Dunay-3U; NATO: Cat House) was built in 1978 as part of the upgraded A-35M anti-ballistic missile system. It is located in Chekhov and was structurally similar to the Dunay-3M - it has a separate receiver and transmitter separated by 2.7 kilometres (1.7 mi). There are two sectors. It was designed to identify the launch of Pershing-2 missiles from West Germany.
In 1995 A-35M was replaced by the A-135 anti-ballistic missile system which used the Don-2N radar. One sector was decommissioned in 1998 and is now ruined and the other is used for space surveillance of satellites in low earth orbit. As a UHF radar it can identify smaller objects (15–40 cm) than the VHF radars such as the Daryal and Dnepr.
The Dunay-3U was commissioned in May 1978 with a life of 12 years. Both sectors were extended until 2000 but one sector (62) was decommissioned in 1998. The other one (61) has been extended in 2001 and 2005 - the last extension was until December 2009, but it may have been extended again. In 2012 the Russian Ministry of Defence issued a tender for the demolition of sector 62.
Before 2003 the transmitter had 30 waveguides each excited by a 100 kW transmitter Since 2003 the station has been operating at a reduced power of 500 kW rather than 1800 kW, with 12 transmitters (out of 24) rather than the previous maximum of 30. The radar is chirped.
The radar's computer system is made up of 10 K340 computers.
Dunay-3U Location of Dunay radar within Moscow regionRead more about this topic: Dunay Radar