Kamisseya

KamiSeya, a SIGINT base located approximately 12.15 kilometers from Yokohama in Japan, was built by Japanese forces and later used by the U.S. Navy in 1945 as a listening post to intercept Soviet and Chinese radio communications. Since World War II, KamiSeya has been the home to U.S. Naval Air Facility (NAF) Atsugi, Japan. The post was later transferred to Okinawa due to heavy electromagnetic interference from nearby Tokyo and Yokohama industrial areas. In Okinawa, KamiSeya is known as the "Sobe base".