Chief Radioman Harry Kidder, USN, one of the ablest radio operators in the US Asiatic Fleet in the early 1920s, became interested in Imperial Japanese Navy (IJN) transmissions. Chief Kidder taught himself Japanese syllabary and IJN radio procedure. The value of his IJN intercepts was recognized up the chain of command to Washington. Influenced by this effort, the Navy established intercept sites around the Pacific.
Chief Kidder was assigned to Washington to teach a select group of radiomen in intercept and traffic analysis. He designed the curriculum --- due to its secrecy, the course was given on the roof of the main Navy building in Washington. Kidder, known by then as “Pappy,” instructed the first classes from 1928 through 1930. They, in turn, were nicknamed the “On-The-Roof Gang” (OTRG).
In 1931, Chief Kidder returned to the Fleet, inspecting and assisting intercept sites across the Pacific. In 1933, he returned to D.C. to instruct three more classes of new Roofers.
He retired in 1935, but returned to active duty in 1941 to help establish new intercept sites for the war effort.
Chief Kidder’s OTRG pioneered SIGINT work and provided essential wartime support; today’s Navy SIGINTers stand on his and their shoulders.