Patrolling the Ether

Patrolling the Ether is a short film made in 1944 depicting amateur radio operators aiding the Federal Communications Commission in monitoring the airwaves for Nazi spy transmissions. It is notable as the first film ever broadcast simultaneously on more than one television station; on 10 April 1944, it was shown on three stations: WNBT, New York, WPTZ Philadelphia and WRGB Schenectady, New York, marking a milestone in the history of network television.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.