Image: Experimental Westinghouse 3GHz microwave transmitter 1933

Description: An experimental 3.3 GHz microwave radiotelephone transmitter developed by scientist Ilia E. Mouromtseff at Westinghouse laboratories in 1933. It was demonstrated at the 1933 Chicago World's Fair. During the 1930s the first low power vacuum tubes capable of generating microwaves were invented. The microphone converts the voice of the man into a varying audio frequency alternating current. The audio modulates the microwaves generated by a small tube at the focus of the shiny parabolic reflector. The microwaves are reflected by the parabolic reflector into a beam, which travels to a receiver several miles away, which converts the electric signal back into sound. The radiated power was about 1 watt.
Usage Terms: Public domain