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Westinghouse engineers with experimental microwave receiver, circa 1932.
Credit: Westinghouse Electric Company, National Museum of American History, Smithsonian Institution, Washington, D.C. 20560
In the early 1930s Westinghouse engineers began to experiment with ultra-short wave radio beams–microwaves–which having many of the properties of light could be focused by suitable mirrors. Westinghouse engineers hoped that these would have military applications because of the narrowness of the beam, which made them difficult to intercept.