On August 11, 1942, the U.S. Patent Office granted Patent No. 2,292,387 for a “Secret Communication System” to two inventors with unusual day jobs. One was the avant-garde composer George Antheil, who had once scored a ballet for synchronized player pianos. The other was Hedy Kiesler Markey, better known to American audiences as Hedy Lamarr, the MGM contract actress being marketed as “the most beautiful woman in the world.”
The patent described a method for guiding a torpedo by radio without the signal being jammed. The transmitter and receiver would jump together across 88 different frequencies in a pattern set by a paper roll, the same mechanism Antheil used for his player-piano compositions. An enemy listening on any single channel would hear only a fragment of static before the signal moved on.
The Navy filed the patent away and did nothing with it. By the time the technique finally went to sea, the patent had expired. Lamarr was no longer under studio contract, and would never receive a cent from the invention that now lives inside every phone, every GPS receiver, and every Bluetooth headset on Earth.
An actress who hated being looked at
Hedwig Eva Maria Kiesler was born in Vienna in 1914 to a Jewish banker father. She left school early for the stage, became briefly notorious at 18 for a nude swim in the Czech film Ecstasy, and at 19 married Friedrich Mandl, an Austrian arms manufacturer.
Mandl kept his young wife as decoration at his weapons meetings. She sat through technical discussions of torpedo guidance, radio control, and the problem that obsessed every navy in Europe: how to stop the enemy from jamming a guided weapon mid-flight. She listened, and she remembered.
She fled her marriage and met Louis B. Mayer, signed with MGM, and arrived in Hollywood with a new surname and the technical vocabulary of an arms-industry insider.
A composer, a player piano, and a torpedo
Lamarr kept a small inventor’s workbench in her trailer between takes. Howard Hughes, who briefly dated her and lent her the use of his engineers, reportedly encouraged her inventive pursuits.
The torpedo idea took shape after a German U-boat torpedoed the SS City of Benares on September 17, 1940. The ship was carrying 90 British children to Canada to escape the Blitz; only 13 of those children survived. Lamarr’s biographer Richard Rhodes traces her serious work on radio-controlled torpedoes to the weeks immediately after the sinking. She wanted a weapon the Nazis could not jam.
The mathematical problem was synchronization. If the torpedo’s receiver and the controlling ship’s transmitter both hopped frequencies, they had to hop in perfect lockstep, otherwise the signal was lost. George Antheil, whom she had met that summer of 1940 at a Hollywood dinner party hosted by Janet Gaynor and Gilbert Adrian, had spent years synchronizing player pianos for his percussion compositions. The paper roll that ran his Ballet Mécanique could just as easily run a radio.
They worked at her dining table through 1941, with Antheil sketching mechanisms and Lamarr handling the radio theory she had absorbed at Mandl’s dinners. They filed the application on June 10, 1941, under her then-married name, Markey. Patent No. 2,292,387 was granted fourteen months later.
What the Navy did with it
Nothing, for a long time. Lamarr and Antheil donated the patent to the National Inventors Council, expecting it to be put to immediate use. The Navy’s response, according to the Smithsonian’s Lemelson Center, was that the device was too bulky to fit inside a torpedo, an objection that hinged on the player-piano mechanism Antheil had used as a stand-in for a future electronic version.
A Navy officer reportedly suggested Lamarr could help the war effort more by selling kisses for war bonds. She did. She raised millions in war bonds.
The patent sat in a file drawer. Its 17-year term expired in 1959.
By the time of the 1962 Cuban Missile Crisis blockade, U.S. Navy ships were carrying communications and sonobuoy systems built around a frequency-hopping spread-spectrum design that traced back, through a chain of mid-1950s contractor work, to the Markey-Antheil patent. Lamarr, by then living quietly in Los Angeles, was not consulted, credited, or paid.
From torpedoes to your pocket
The principle the patent described, splitting a signal across many frequencies in a pattern only the sender and receiver share, turned out to be useful for far more than guided weapons.
It is how a GPS satellite reaches a phone in a parking garage without being overwhelmed by interference. It is why a Wi-Fi router can serve a dozen devices at once on the same crowded 2.4 GHz band. It is what allows a Bluetooth earbud to stay locked to one phone in a coffee shop full of other Bluetooth earbuds. The broader family is called spread spectrum, and its consumer descendants run inside almost every wireless chip manufactured since the mid-1990s.
Qualcomm built a multi-billion-dollar business on CDMA cellular standards, a related branch of the spread-spectrum family. The Wi-Fi Alliance and the Bluetooth SIG built global ecosystems on adjacent variants. None of those companies owed Lamarr anything, because the originating patent had expired before any of them existed.
Recognition, decades late
For most of her life, Lamarr’s contribution went unmentioned in tech histories. The first serious attempt to credit her came in 1997, when the Electronic Frontier Foundation gave her and Antheil their Pioneer Award. She was 82 and reclusive. She did not attend, but recorded a brief message. Her son Anthony Loder has since recounted her three-word reaction on hearing the news: “It’s about time.”
She died in Casselberry, Florida on January 19, 2000, at 85. Her estate was modest. Antheil had died in 1959, the same year the patent lapsed, and never knew his synchronization trick would end up in a billion pockets.
The National Inventors Hall of Fame inducted them both, posthumously, in 2014. Google built a Doodle around her in 2015. Documentaries followed. The Austrian government named November 9, her birthday, as Inventors’ Day, an honor that arrived a decade and a half after her funeral.
The shape of a regret
Lamarr’s late interviews on the subject are matter-of-fact, more curious than bitter, more interested in what came next than in what had been taken. She told her son she had never been paid because she had given the patent away, freely, during a war. The bureaucratic accident that the Navy declined to deploy it until the patent had expired was, to her, just one of those things. The technology had been hers and Antheil’s; then it belonged to the world.
Anyone who has paired headphones to a phone, opened a maps app in a tunnel, or watched a video stream over hotel Wi-Fi has used the principle she filed for in 1941. The frequencies are different now, the player-piano roll is a silicon chip, the carrier waves jump thousands of times per second instead of dozens. The trick is the same trick.
In a Smithsonian archive of their invention papers, donated by Lamarr’s daughter in 2023, the original pencil sketches still survive: eighty-eight slots in a paper roll, one for each key on a piano, with handwritten notes in the margins explaining how the transmitter and the receiver will know, at every instant, exactly where to listen.
