On the morning of 7 December 1941 the SCR-270 radar at the Opana Radar Site on northern Oahu detected a large number of aircraft approaching from the north. This information was conveyed to Fort Shafter’s Intercept Center. The report was dismissed by Lieutenant Kermit Tyler who assumed that it was a scheduled flight of aircraft from the continental United States. The radar had in fact detected the first wave of Japanese Navy aircraft about to launch the attack on Pearl Harbor.

The Opana Radar Site is a National Historic Landmark and IEEE Milestone that commemorates the first operational use of radar by the United States in wartime, during the attack on Pearl Harbor. It is located off the Kamehameha Highway just inland from the north shore of Oahu, Hawaii, south of Kawela Bay. It is not open to the public.