What do Clark Gable, Judy Garland, Spencer Tracy, Lana Turner, and James Stewart have in common? They all starred in movies with a clever Austrian immigrant named Hedwig Kiesler, who designed and patented a “Secret Communication System” to ensure that World War II Allied torpedoes hit their targets without interference from the enemy. Today, we use concepts from Kiesler’s design in Wi-Fi, Bluetooth, GPS, and cellular technologies.  

Proclaimed to be “the most beautiful woman in the world,” Kiesler is better known to classic movie fans as Hedy Lamarr. She capitalized on her beauty, despite famously proclaiming that “any girl can be glamorous – all you have to do is stand still and look stupid.” Ms. Lamarr achieved fame and financial success through her looks and movie roles, but it was her pursuit of inventing that set her apart from other Hollywood icons.

From Austria to Hollywood
Born Hedwig Eva Maria Kiesler in 1914 to Jewish parents, Ms. Lamarr lived a comfortable, privileged childhood in Vienna, Austria. She set her sights on acting early in life, leaving  school at age 16 to find work film and stage work.  Her brief European movie career was put on hold when she married a wealthy Austrian ammunitions manufacturer named Freidrich Mandl, who sold munitions to the Nazis.  

The Mandls often entertained high- powered military people, with whom Mr. Mandl openly discussed war time technology such as submarines and remote controlled torpedoes. Ms. Lamarr quietly absorbed the information for future use, while plotting to leave her husband, who turned out to be a control freak and regarded her as more of a trophy than a wife. “He was the absolute monarch in his marriage,” she wrote. “I was like a doll in a beautiful, jeweled case … a thing, some object of art which had to be guarded” in a “prison of gold.” The two split within five years.

After divorcing Mr. Mandl, Ms. Lamarr made her way to Hollywood in 1937, negotiating a generous movie contract with Louis B. Mayer of MGM Studios as they sailed from London to America. En route she changed her name, and as Hedy Lamarr she starred in 25 movies, including the lavish 1949 biblical drama Samson and Delilah. Some say audiences were so awed by her beauty, they gasped when she first appeared on the screen.

Part-time Inventor
In between movies, Ms. Lamarr shunned the Hollywood social scene, instead spending time at her drafting table inventing, according to Ruth Barton, author of “Hedy Lamarr: The Most Beautiful Woman in Film.” Ms. Lamarr’s inventions included a tablet that would turn water into soda-pop, although she lamented that the results tasted more like Alka Seltzer.
(Aviation magnate Howard Hughes, a friend and one-time romantic interest, loaned her some chemists to help with
the creation.)

She also invented an accordion-type attachment for a Kleenex box to help dispose of used tissues; a new kind of traffic stoplight; a device to help people get in and out of the bath; a fluorescent dog collar; a skin tautening technique based on the action of an accordion; and even modifications to the Concorde supersonic passenger jet. But her most famous invention was meant to thwart the Nazis, for whom she held a deep disdain.  

Beauty and the Bomb
Fortunately for Ms. Lamarr, she left Austria before the Nazis annexed her homeland and began terrorizing Europe. She also brought her mother to Los Angeles from London in the early 1940s. (Her father had died of a heart attack in 1935.) But even from a distance the war weighed heavily on Ms. Lamarr, especially after British ships transporting children to safety in Canada were sunk by German U-boat torpedoes. Scores of children perished, and Ms. Lamarr felt she had to do something to weaken the Nazis and help the Allied cause.  

Ms. Lamarr believed she had learned enough about wartime weapons development from her former husband to help the U.S. government, according to Richard Rhodes, author of “Hedy’s Folly: The Life and Breakthrough Inventions of Hedy Lamarr, the Most Beautiful Woman in the World.” She enlisted the help of her friend, American avant-garde composer George Antheil, who had worked as a government munitions inspector. Some of his musical compositions involved synchronizing multiple player pianos, a concept that would drive their invention.

“I got the idea for my invention when I tried to think of some way to even the balance for the British,” Ms. Lamarr told the U.S. military’s Stars and Stripes newspaper in 1945. “A radio controlled torpedo I thought would do it.”  

Ms. Lamarr envisioned a wireless remote-controlled torpedo guided by a jam-proof communication system. After the torpedo was launched, an airplane would monitor its movement and report course corrections back to the launch ship, which would readjust the torpedo’s path until it hit the target. The radio signal between plane and ship would transmit over constantly changing frequencies so it could not be intercepted or jammed by the enemy – an action she called “frequency hopping.” Ms. Lamarr and Mr. Antheil designed a separate frequency hopping system for use between the ship and torpedo. (They also designed an anti-aircraft shell that would explode when it sensed its proximity to the target.)

Mr. Antheil proposed modeling the system on the perforated paper rolls used in player pianos. Each hole in a piano roll corresponded with each of 88 piano keys. For Ms. Lamarr and Mr. Antheil’s system, each hole in their modified rolls would correspond to 88 different radio frequencies. The rolls would be synchronized so the airplane and ship could always communicate on the same changing frequency. After submitting an application with detailed schematics of the system, Hedy Kiesler Markey (the name of her second ex-husband) and George Antheil were granted patent #US2292387A for their “Secret Communication System” in 1942. The National Inventors Council offered the invention to the U. S. Navy for consideration. The Navy apparently mistook references to player piano rolls to mean the system would use the same large paper rolls and deemed them “too bulky to be incorporated in the average torpedo.” Mr. Antheil argued that the technology could be scaled down to fit into a wristwatch, but the Navy took a pass and frequency hopping lay dormant for more than a decade.

Frequency Hopping and Spread Spectrum
Unbeknownst to Ms. Lamarr and Mr. Antheil, their patent resurfaced in the mid-1950s, when the Navy gave a copy to an engineering lab charged with designing a floating sonar buoy. The “sonobuoy” would use frequency hopping to detect and secretly transmit the location of enemy submarines, although it was never built. Frequency hopping started appearing in other Navy communication systems, and eventually took on the name “spread spectrum,” to indicate that a radio signal was spread out over a larger range of frequencies – or more bandwidth – than actually needed.  

Spread spectrum encompasses numerous types of transmissions. The most commonly used are: “frequency hopping spread spectrum,” which transmits signals over a range of radio frequencies but only one at a time; and “direct sequence spread spectrum,” which transmits over the entire range of frequencies all at once. Each has advantages for preventing detection and jamming, as well as reducing noise and interference from other signals. Today’s Wi-Fi, Bluetooth, cordless phones, GPS, wireless networks, bar-code readers, and many military systems use spread spectrum signals.

“In all of the consumer applications – cell phones, WiFi, Bluetooth – it’s not so much that we’re worried like the military about an intentional jammer,” says Randall Berry, Ph.D., a Northwestern University engineering and computer science professor whose research focuses on wireless communication and networks. “It’s more that I might have my Bluetooth device in the same room as yours, and we want them both to operate without jamming each other unintentionally.” Frequency hopping prevents multiple Bluetooth devices from interfering with each other by transmitting over a wide range of frequencies, Dr. Berry explains. Different Bluetooth devices are designed to work in the same area without having to coordinate with each other or rely on a network to direct them.

Fifty Years Later, Recognition and Awards
More than half a century after their patent was granted, Ms. Lamarr and Mr. Antheil (posthumously) received formal credit for their Secret Communication System and the contribution they made to modern electronic communication. In March 1997, the Electronic Frontier Foundation (EFF) awarded Ms. Lamarr and Mr. Antheil their Pioneer Award. She also received the Inventors Club of America’s Chariot Award, the Austrian Association of Patent Holders’ Viktor Kaplan Medal, Lockheed’s Milstar award, and the Bulbie Gnass Spirit of Achievement Award.  Inventor’s Day in Austria, Germany and Switzerland occurs on Nov. 9, Ms. Lamarr’s birthday. And numerous science and technology awards around the world bear her name.  

Although the Secret Communication System never helped blow up Nazi ships, as Ms. Lamarr had hoped, it is worth noting that she successfully raised $25 million worth of war bonds – the equivalent of $390 million in today’s currency. So she succeeded in making a substantial contribution to the Allied war effort, if not with her brains then with her time, energy, and popular appeal.  

In the years following Ms. Lamarr’s death on Jan. 19, 2000, Bluetooth and Wi-Fi technologies were incorporated into phones, cameras, headphones, hands-free headsets, speakers, printers, televisions, computers and tablets. Whenever we use our cell phones, listen to music through a Bluetooth speaker, or print documents over a Wi-Fi connection, we honor Ms. Lamarr’s technological foresight, her dedication to helping the Allies defeat a terrible enemy, and the ingenuity that defined her as much more than just another Hollywood beauty.

Meg Evans has written science stories for the Evanston RoundTable since 2015, covering topics ranging from local crayfish, coyotes and cicadas to gravitational waves, medical cannabis, invasive garden...