Ground Equipment Facility J-31 (San Pedro Hill Air Force Station during the Cold War) is a Joint Surveillance System radar site of the Western Air Defense Sector (WADS) and the Federal Aviation Administration's air traffic control radar network [1] for the Los Angeles Air Route Traffic Control Center. The facility's Air Route Surveillance Radar Model 1E with an ATCBI-6 beacon interrogator system are operated by the FAA and provide sector data to North American Aerospace Defense Command. The site provided Semi-Automatic Ground Environment data to the 1959-66 Norton AFB Direction Center for the USAF Los Angeles Air Defense Sector. The site also provided Project Nike data to the 1960-74 Fort MacArthur Direction Center ~ away for the smaller US Army Los Angeles Defense Area—as well as gap-fill