Sapfir-25 was developed by a team under Kirpichev as a very high priority task after the defection of Viktor Belenko to Japan in 1976 compromised the MiG-25’s radar. For speed of development, an existing radar had to be selected, and the MiG-23ML’s radar, with its lookdown capability, was the obvious choice. Changes included the use of a larger antenna, which helped increase the search range in lookup mode to 100-115km against a bomber target, 90km against a fighter. Tracking range increased to 75-80km against a bomber, and 60km against a fighter. Weight 337kg. In look-down/shoot-down mode against a closing target range was reduced by 30%, against a receding target a further 40%. Compared to Smerch-A it could engage faster targets at higher altitudes, featured greater search and tracking range, provided lookdown/shootdown capability and close combat modes. It had 30 degree (+-15deg) and 60 degree (+-30 deg) search patterns. It also had better anti-jamming protection. Azimuth scanning limits were slightly reduced to +-56 degrees, elevation to +52/-42 degrees, by the twist-cassegrain antenna design.