The War Department’s 1944 guide to FM radio is still a great explainer
The U.S. War Department made this training film in 1944 to explain frequency modulation to soldiers, and it opens with the perfect sales pitch: two GIs playing ping pong while listening to the radio. A third man fires up an electric razor, and the AM signal turns to mush. Someone switches to FM. Problem solved.
What follows is a 28-minute breakdown of wh…
