Hedy Lamarr: From Hollywood glamour to frequency-hopping, a film star’s enduring legacy

With concert pianist George Anthiel, Lamarr developed a torpedo guidance system based on a phenomenon known as radio frequency-hopping.
01 September 2021
By Rebecca Pool
Hedy Lamarr
Film legend Hedy Lamarr was left off a patent for a frequency-hopping device because she was not a US citizen.

From beginning to end, the life of 1940s Hollywood film star Hedy Lamarr, was extraordinary. She rose to fame in hit movies alongside the likes of Clark Gable and James Stewart, but perhaps less well known was her wartime invention of torpedo guidance based on a phenomenon known as radio frequency-hopping. In fact, Lamarr has been dubbed the "Mother of WiFi" because of the ongoing relevance of her extraordinary scientific work.

Lamarr married six times, had three children, and led the kind of life most people can only imagine. Despite her silver screen stardom and the spectacular legacy her invention left the world of wireless communications, she died quietly in 2000 without any compensation for her engineering efforts.

Lamarr's daughter Denise Loder-DeLuca says that if her mother had been born at a later time, the outcome would be different. "What my mother achieved is now a triumph, but she didn't see a penny for it," Loder-DeLuca says. "Hedy wasn't business-minded, she was just incredibly creative, and while I'm sure women struggled then, it's outrageous she wasn't taken seriously—she was told just go back to being pretty, go back to your movies."

Born in Austria in November 1914, Hedwig Eva Maria Kiesler was catapulted into the public eye in 1933 when she frolicked naked in Ecstasy, a Czech feature film later denounced by the Pope and Adolf Hitler. A year later, she married Viennese arms merchant, Friedrich Mandl, reportedly Austria's third richest man. Four years on, she'd left that marriage, but not before sitting in on many a dinner party where, according to Richard Rhodes' biography, Hedy's Folly, much discussion on weaponry took place.

On leaving Mandl, Hedy set off for London, where she met Louis B. Mayer of Metro-Goldwin-Mayer (MGM) who was scouting for talent across Europe. He persuaded her to change her name to Hedy Lamarr and introduced her to Hollywood where she swiftly became an acting sensation.

Around this time, she also encountered aviation tycoon Howard Hughes. Recognizing her inventive streak, he lent her two chemists and others so she could develop a Coca Cola tablet to mix with water to replicate the much-loved soda drink at home. The cola tablet didn't work out, but as Lamarr recounted to Forbes journalist Fleming Meeks, she took the opportunity to suggest that Hughes streamline the design one of his airplane's square wings to speed up flight. He did.

Crucially, in 1940, Lamarr also met George Anthiel at a party. He was an experimental concert pianist, having composed the incredibly complex Ballet Mecanique, and she was harboring a wealth of fundamental munitions knowledge. Together they devised a secret communications system for ships and torpedoes that they hoped would help defeat Nazi Germany.

At the time, Germany's U-boats were devastating the Allied forces and evading British torpedoes, which, guided by radio transmission on a single frequency, could be intercepted by enemy forces. To counter this, Lamarr came up with the idea that a radio signal could instead be transmitted over multiple, rapidly changing, or hopping, frequencies, making torpedo jamming much more difficult.

Hedy Lamarr patent

Drawing from a US patent application filed by Hedy Lamarr and George Anthiel.

Harnessing frequency hopping to guide torpedoes was all well and good, but those shifting frequencies had to also take place in exact time-synchronization with the radio transmitter guiding the torpedo. Enter Anthiel. The composer had already experimented with synchronizing 16 player pianos using punched tape, and he and Lamarr applied a similar principle to their radio guidance system.

They proposed using a pair of synchronized, perforated rolls, controlled by calibrated clockwork motor drives, to switch the signal between the transmitter and torpedo. These drives could be triggered simultaneously by a locking pin that would release the moment the torpedo was fired.

Working with Caltech's Professor Samuel Mackeown, Lamarr and Anthiel detailed their invention in US patent 2292387A, which stated, "In a conventional player piano record there may be 88 rows of perforations, and in our system such a record would permit the use of 88 different carrier frequencies..." Their unconventional approach may well have scuppered torpedo interception from enemy forces, but it was also a precursor to the frequency-hopping spread spectrum technology now ubiquitous in WiFi, GPS, and Bluetooth.

"The idea of frequency agility wasn't new, but I don't think anyone had thought about using it to protect communications," says Karl-Arne Markstrom, command and control systems consultant, and Union Radio-Scientifique Internationale member.

"The real breakthrough in this was to combine the sequential machine with frequency hopping," he adds. "It's hard to tell what made them think in these terms...but they combined these [ideas] to control torpedoes—this was new thinking."

Without doubt, Lamarr and Anthiel's invention was ahead of its time. Anthiel reportedly claimed that their invention's mechanisms could ‘be fitted inside of dollar watches.' A patent was granted in 1942, but according to Rhodes, the US Navy simply filed it away, claiming the guidance system was too heavy.

Investigations by Alexandra Dean, writer of the 2017 documentary Bombshell: The Hedy Lamarr Story, suggest the Navy wasn't willing to take the work of an actress and a pianist seriously. According to Dean, the US government seized the patent as the "property of an enemy alien" because Lamarr was Austrian.

Lamarr and Antheil's idea was revisited in the 1950s, with an electronic version of frequency hopping developed for a sonobuoy, a device dropped from an airplane to detect submarines via sonar and securely transmit that data back to the plane. The concept was also used by the US Navy during the 1962 Cuban Missile Crisis. American ships armed with torpedoes were guided by a frequency-hopping system.

Loder-DeLuca believes her mother was at her brightest when working on her secret communication system. "My mother was tough—she always stuck up for herself, had a spunky attitude, and never felt sorry for herself, but I think her story would be totally different today," she adds.

Indeed, in 1997, an 84-year-old Lamarr received the American Electronic Frontier Foundation's Pioneer Award. When notified of the honor, reportedly she said, "Well, it's about time." In 2014, she was inducted into the National Inventors Hall of Fame for helping to create an early form of wireless communications.

Experts disagree on the significance of Lamarr and Antheil's scientific contributions. According to Robert Walters, author of Spread Spectrum: Hedy Lamarr and the Mobile Phone, "Their idea was good and had some influence on wireless communications... but I think the main thing Lamarr and Antheil have added to the whole boring world of frequency hopping and steering torpedoes is glamour."

Glitz or no glitz, Lamarr's frequency-hopping idea came about during a very different era for women. Markstrom's colleague, Professor Asta Pellinen-Wannberg of the Swedish Institute of Space Physics, emphasizes that women were not supposed to be both beautiful and clever in the 1940s.

"I also think they [Lamarr and Antheil] had this power—they were not from that [technical] field, so they could look at a problem differently," Pellinen-Wannberg says. "We see inventions that were made ahead of their time by the wrong people—and I think if Lamarr was born 40 years ago, she would probably be a professor now."

Lamarr died peacefully on 19 January 2000 in Florida. Towards the end—in the internet era informed in part by Lamarr and Anthiel's ideas—Loder-DeLuca says, her mother hadn't truly realized the impact her patent had on the world. But it did, and Lamarr's ideas and concepts live on.

Rebecca Pool is a science and technology journalist based in the UK.

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