SPN-500s carried a rangefinder as well as Yakor (NATO designation Sun Visor) fire-control radar. Air search capability was provided by the Fut-N (NATO designation Slim Net) radar with anti-aircraft fire control provided by Fut-B (NATO designation Hawk Screech) radars. The main air-search radar was the Giuis-2 (NATO designation Cross Bird), a Soviet development of the wartime British Type 291 radar. It had a range of against aerial targets and against surface targets. The main surface-search radar was Rif-A (NATO designation Ball End) that had a range of against surface targets. The Stalingrads also had Neptun and Nord navigational radars. Soviet electronics were still fairly primitive during this period and the trials of the light cruiser Sverdlov, which carried many of these systems, revealed that the effective range of the Rif-A surface-search radar was less than that of the Yakor and Zalp fire-control radars. There were also problems transferring data from the Giuis-2 air-search radar to the Yakor and Fut-B anti-aircraft fire-control radars, which was a serious problem when dealing with high-speed aircraft. The Giuis-2 also interfered with ultra-shortwave radio reception. Korall radar-jammers were mounted on either side of the mainmast as well as a Machta system on the foremast. Solentse-1P infrared detectors were carried on either side of the superstructure. Fakel-MO and Fakel-MZ antenna comprised the IFF system. A Gerkules sonar was also fitted in addition to various radio direction finders. Missile variant The TsKB-17 design bureau proposed variants of the design with both cruise and ballistic missiles. The ballistic missiles would have been launched from vertical tubes replacing the forward turrets, and in one version, the entire main armament. The proposal was dropped because both types would have needed a fully stabilized launching platform to give them any chance of hitting their targets and that the ballistic missiles would need three hours of preparation time. Construction The first sections of Stalingrad had been laid down in November 1951 in Slipway "O" of the Marti South Shipyard in Nikolayev where a , Sovetskaya Ukraina, had begun construction in 1938, but the slipway itself was in need of reconstruction and its lower end was occupied by the hull of the Sverdlov-class light cruiser Mikhail Kutuzov which was scheduled for launch at the end of 1952. Moskvas keel was laid down in September 1952 by the Baltic Works in Leningrad. The unnamed third ship was laid down at Yard 402, at Molotovsk