Col. Blair conceived and developed his radar theory during the 1920s and 1930s while the Director of the Research and Engineering Division of the Signal Corps. But because it was invented during World War II, it was important to maintain the secrecy of such a weapon. Therefore, the government ordered that the patent no be applied until after the war was over.

When Col. Blair applied for the patent in 1945, it was challenged by two parties and took a special legislative act, patent office hearings and a great deal of research, before it was determined that Col. Blair was, indeed, the inventor and finally received his patent in 1957. The Army called the patent "as important and far reaching in it's military application as the first U.S. patent issued on the telephone was to commercial communications."

Before entering government services, Col. Blair was a high school principal and an associate in mathematics. He entered the University of Chicago as a student and assistant instructor. He graduated in 1906 with a doctorate in Philosophy and entered the government services with the U.S. Weather Bureau the same year. Following entry of the U.S. into World War I, Blair was commissioned a major, first assigned to the Aviation Corps in France, but then transferred to the Signal Corps in 1918. He remained in the service after the war as a career officer and scientist. He retired in 1938.