My bet is for a modern (probably) phased array EW radar.
There is a guy who is expert on this field.
http://geimint.blogspot.com/

In his forum, you probably could got answer.
http://www.makephpbb.com/phpbb/index.php?mforum=geimint

Hpasp
Free SAM Simulator, "Realistic to the Switch"
(U-2 over Sverdlovsk, B-52's over Hanoi, F-4 Phantoms over the Sinai, F-16's and the F-117A Stealth bomber over the Balkans.)
http://sites.google.com/site/samsimulator1972/home

Book from the author - Soviet Nuclear Weapons in Hungary 1961-1991
https://sites.google.com/view/nuclear-weapons-in-hungary/
thumbsup