NAIP Patent Blog

By Rebecca Day
Many know Hedy Lamarr as a Hollywood legend – one of the most beautiful actresses to ever grace the silver screen. Yet all her beauty and glamor were only secondary to her brilliant mind. That is why Hedy Lamar is also known through another title: Inventor. In the 1940s she co-invented and patented an early form of frequency hopping technology that was revolutionary in its thought. This breakthrough concept would later forge the path for the development of modern wireless communication.


Born Hedwig Eva Maria Kiesler in Vienna in 1914, Hedy became an actress in the 1930s, appearing in a number of German and Czech films. Her husband, fellow Austrian Friedrich Mandl, was an arms manufacturer and – despite being part-Jewish – a Nazi sympathizer. In the Austria of the 1930s, with the rise of fascism and anti-Semitism, such choices often meant the difference between life and death. Hedy, a Jew herself, decided to leave her husband and her country. At a party one night, wearing all the expensive jewellery she possessed, she drugged her husband with the help of her maid, and fled Austria. She first went to Paris, then London, where she met Louis B. Mayer, co-founder of the famous MGM studios. Impressed by her beauty, Mayer offered her the chance to move to Hollywood, where she became a glamorous regular of films of the late '30s and '40s.

In 1939 Europe exploded into full-out war. By the summer of 1940, most of Europe was occupied by German troops, leaving only Britain and the Commonwealth, with economic support from the United States, to repel the Axis advance. Deeply troubled by the threat Nazi Germany posed to the world, Lamarr shared her concerns with her neighbor, German immigrant and avant-garde composer and pianist George Antheil. In their conversations the biggest problem they saw was that Germany's naval power was vastly superior to the Allies'. At the time, the most reliable way of attacking ships was to use radio-controlled torpedoes. The problem, however, was that the radio control left the torpedoes vulnerable to tracing and jamming.

Fortunately, Hedy had gained considerable knowledge of weaponry during her marriage to Friedrich Mandl. Mandl's position as the chairman of a prominent armaments firm required him to hold many defense meetings which Hedy had often sat in on. Dinner table conversations revolved around defense technology and munitions. Putting this invaluable background knowledge to use, she realized that if the frequency of the radio controlling technology could be constantly changed (a technique now known as frequency hopping) the torpedo would be virtually untraceable.

Antheil's musical background provided the missing piece to the solution. During his composing career he had written a piece for sixteen synchronized player pianos. A player piano, often called a pianola, is a piano that uses a device called a piano roll, which is a perforated piece of paper moved over a tracking bar, to create music mechanically. The position and length of the holes determines which note is played. With such a device inserted into both the torpedo and the torpedo transmitter, the frequency at which the torpedo is controlled could constantly be changed, while ensuring the torpedo and transmitter remained in synchronization. On June 10th, 1941, Hedy and George submitted their invention, titled "Secret Communications System", to the USPTO.

Unfortunately, both the US government and the military expressed considerable doubt about the technology's practicality. George Antheil felt that this suspicion largely stemmed from their seemingly incongruous merging of the unrelated areas of musical technology and weaponry. In an attempt to render the invention more accessible, Antheil and Lamarr had drawn analogies to the concept of the player piano, a technique Antheil feared the USPTO (and the United States Navy) viewed as unscientific. Nevertheless, in August 11th, 1942, their "Secret Communications System" was granted a patent, and published as Patent No. 2,292,387.

Antheil's reasons for the Navy hesitance towards his and Lamarr's invention were largely misplaced. The electronics available in the 1940s were simply not sophisticated enough to put the technique into practice. In truth, Lamarr and Antheil's frequency hopping technique was so far ahead of its time that it would not be used until 1957, when it was rediscovered by Sylvania Electronic Systems and named "spread spectrum". Furthermore, the technique would not be perfected until the 1960s, with the development of the now ubiquitous transistor. Only in 1962 was patent No. 2,292,387 finally used for its intended purpose by the United States Government during the Cuban Missile Crisis. By this time, however, the patent had already expired. Neither George Antheil nor Hedy Lamarr made any money from their invention.


Lamarr and Antheil's work is widely considered to be the basis of the field of frequency changing. The frequency hopping idea developed by Lamarr and Antheil forms the ideas behind much of modern wireless communication technology, and even the anti-jamming techniques currently employed by the US government's Milstar defense communication satellite system.

Hedy Lamarr largely retired from films in the 1950s. During the Second World War, she had wanted to become a member of the National Inventors Council, but was told she would be more use to the war effort by using her Hollywood celebrity status to sell war bonds. In 1997, she was finally credited for her astonishing achievement by the Electronic Frontier Foundation, where she was reported to remark "It's about time". George Antheil was credited posthumously, having died in the 1960s. Perhaps 2008 will be the year when people truly realize the impact of their innovative concept. In July, Elyse Singer brought her play "Frequency Hopping", detailing the story behind George Antheil and Hedy Lamarr's secret communications system, to the stage. It has been hailed by the New York Times as "inventive" – something Hedy Lamarr would surely understand.

US Patent# 2,292,387 can be found here.

Posted in: Engineers, Inventors, Other | | |