Hedy Lamarr: Hollywood star, secret scientist

The annual German Inventors’ Day is held on Nov. 9, the birthday of  Hedwig Eva Maria Kiesler, a.k.a. Hedy Lamarr.

Kiesler made her film debut in 1930, at age 17. Two years later she earned notoriety for her nude romp through the woods in the Czech film “Ecstasy.” Her arranged marriage to Austrian munitions dealer Fritz Mandl triggered another aspect of her right-brain personality. Sitting in on arms-design meetings at Mandl’s company, she came up with the idea of designing a radio-controlled torpedo, but the idea was rejected because the signal could be too easily jammed. 

After the “Anschluss” in 1928, Kiesler left her husband and moved to London. There she met Louis B. Mayer, who signed her for MGM and changed her name to Hedy Lamarr. Even with her busy schedule making films that included “Algiers,” “White Cargo” and “Tortilla Flats.” Lamarr the inventor continued to think about the radio-controlled torpedo. But the inventor did not fit MGM’s image of Lamarr as a glamorous movie star and her creative side was a well-kept secret in Hollywood. Still, Lamarr was so passionate about helping the war effort that she seriously considered abandoning acting to join the National Inventors Council full time.

Lamarr the inventor continued to think about the radio-controlled torpedo. Working with composer George Antheil, she conceived the idea of using frequency-hopping to prevent jamming of the signals sent to guide the torpedo. Antheil drew on his use of synchronized player pianos in his composition “Ballet Mécanique” to design a frequency-hopping transmitter. To signal, the transmitter would use a slotted-paper roll, like those of a player piano, using a pattern of 88 changing frequencies. The receiver mounted on the torpedo would contain a duplicate slotted-paper roll that would recognize only signals that matched those sent by the transmitter. Lamarr had hoped that this idea would help the war effort, and she donated the resulting patent to the U.S. government for this purpose. It was not until the initial 1942 patent expired and electronics was substituted for the slotted paper rolls that the concept of frequency-hopping, known today as “spread spectrum,” was adopted.

Today most households employ a digital version of this very technology in a variety of electronic applications from cordless telephones to automotive navigation systems to suppress inadvertent interference with the signal (rather than the intentional interference, or jamming, of concern to Hedy Lamarr).

EDITOR’S NOTE: This is one in a series on Jewish women scientists.

TOBY ROSSNER (tobyross@cox.net) was the director of media services at the Bureau of Jewish Education from 1978 to 2002.