Dunay-3U (Cat House) Radar

The Dunay-3U (Rus: Дунай-3У, 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.


In 1995 A-35M was replaced by the A-135 anti-ballistic missile system which used another radar, the Don-2N. One sector (east one) of the radar was decommissioned and is now abandoned while the other (east one) is still used for surveillance of satellites in low Earth Orbit. As a UHF radar it can identify smaller objects (15–40 cm) than the VHF radars.


The Dunay-3U was commissioned in May 1978 with a lifespan of 12 years, later being extended by ten more. Sector 62 of the radar was nonetheless decommissioned in 1998 while sector 61 had its service life extended again in 2001 and 2005 – the last extension lasting until December 2009, but it may have been extended again since. In 2012 the Russian Ministry of Defense 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.