Hedy Lamarr and frequency hopping
We’ve been learning about radio frequency transmission in sensors class, and today Ari told us about how actress Hedy Lamarr and composer George Antheil came up with the idea of frequency hopping to avoid jamming of radio-controlled torpedoes during WWII. The best part was their idea to use a roll from a player piano, on both the torpedo and transmitter, to change the transmission frequencies. I had fun looking at their patent here.
From http://hypatiamaze.org/h_lamarr/scigrrl.html:
Hedy knew that “guided” torpedos were much more effective hitting a target, a ship at sea for example. The problem was that radio-controlled torpedos could easily be jammed by the enemy. Neither she nor Antheil were scientists, but one afternoon she realized “we’re talking and changing frequencies” all the time. At that moment, the concept of frequency-hopping was born.
Antheil gave Lamarr most of the credit, but he supplied the player piano technique. Using a modified piano roll in both the torpedo and the transmitter, the changing frequencies would always be in synch. A constantly changing frequency cannot be jammed.
They offered their patented device to the U.S. military then at war with Germany and Japan. Their only goal was to stop the Nazis. Unfortunately or predictably, the military establishment did not take them or their novel invention seriously. Their device was never put to use during World War II.
From http://en.wikipedia.org/wiki/Hedy_Lamarr#Frequency-hopped_spread_spectrum_invention:
Lamarr’s frequency-hopping idea served as the basis for modern spread-spectrum communication technology used in devices ranging from cordless telephones to WiFi Internet connections.
Lamarr was awarded by the EFF in 1997 for her contributions to this invention.
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