SON-9 is a type of Russian/Soviet fire director radar for air defence guns including the 57 mm, 85mm, and 100 mm, and 130mm anti-aircraft guns. The design was based on an older SON-4 Soviet design that was in turn based on a US-origin SCR-584 system, the plans for which were provided to the USSR during the Second World War. It was used in combination with the PUAZO 6/60 fire director.