Hedy Lamarr: inventor of frequency hopping

A summary of the life and times of Hedy Lamarr, the famous Hollywood actress and beauty and inventor of the frequency hopping system of spread spectrum radio transmission

Hedy Lamarr was once known as the world's most beautiful woman. Yet apart from being a Hollywood icon, Hedy Lamarr had a varied and interesting life and was an accomplished scientific inventor. With a co-inventor George Antheil she invented a radio system for preventing jamming using a system known as frequency hopping. This is in widespread use today. In her film career Hedy Lamarr caused a worldwide scandal when she appeared nude on screen in a film and she went on to become one of Hollywood's biggest stars in the 1940s. In her private life it is said that she escaped from her jealous first husband by drugging a guard and in total she married six times. Yet despite all her claims to fame Hedy Lamarr died in modest surroundings in Florida in the USA having made not a penny from her scientific invention.

Early days

Hedy Lamarr was born Hedwig Eva Marie Kiesler on 9th November 1913 in Vienna, Austria. She was the daughter of a wealthy Jewish banker and his wife. Her upbringing was very stable but from an early age she dreamt of becoming an actress. By the time she had become a teenager Hedy Lamarr had decided to drop out of school to follow her desire, seeking her fame as an actress.

The first role that Hedy Lamarr took was a bit part in a German film the title of which translates as "Money on the Street" which was released in 1930. She then appeared in two more films in 1931.

Hedy Lamarr was particularly attractive and it was her fifth film that was released in 1932 that took her into the limelight. The film entitled "Extase" (Ecstacy) had long scenes in which Hedy Lamarr appeared nude. The scenes created a world wide sensation, and caused the film to be banned in the USA, although a considerably edited version was released some years later. It was particularly noticed at the Vienna Film Festival, and it was said to be a particular favourite with the men there! It was also banned in Nazi Germany by Adolf Hitler because Lamarr was Jewish.


Hedy Lamarr married Fritz Mandl, a munitions manufacturer and a Nazi sympathizer. He was a very jealous husband and tried to buy back all the copies of the film that he could. It was said that even Benito Mussolini had a copy that he refused to sell.

The marriage to Mandl did not last long and was in fact a disaster. Hedy Lamarr was unable to tolerate Mandl's jealousy and she escaped one evening by drugging a guard so that she could leave unnoticed. How much of the method of escape has been elaborated is unclear, but their marriage ended in 1937.

Months later Hedy Lamarr was spotted by the MGM mogul Louis B Mayer. He signed her as a result of her notoriety, but insisted that she change her name and make less sensational films. Lamarr made a number of films under Mayer. Her first was in 1938 as Gaby in the film Algiers. This was followed a year later in 1939 with a role in Lady of the Tropics. Then in 1942 she landed a starring role in White cargo. Unfortunately she turned down leading roles in both Gaslight and Casablanca.

During the 1950s her career began to decline and MGM did not renew her contract. This resulted for many reasons. It was partly as a result of her reputation for being very difficult on set, and as a result of Hollywood's indifference to ageing beauty she made fewer films. However she did appear in a few other roles, the last being in The Female Animal in 1958.

Lamarr the inventor

Despite no formal scientific training, Hedy Lamarr had an exceptional scientific mind, and with her co-inventor George Antheil, they developed a system for radio communication today that is at the core of many communications systems, including the GSM cell phone system that is in use by over 1.2 billion subscribers worldwide.

Hedy Lamarr and George Antheil first met in 1940 when they both lived in Hollywood. Antheil was an accomplished musician and concert pianist. Being neighbours they often talked and Lamarr mentioned that she had an idea that she was thinking of contributing to the newly established National Inventors Council in Washington.

The basic idea that Hedy Lamarr had in her mind was for a form of radio control mechanism for torpedoes. Although this idea was not new, the idea of preventing jamming by using a frequency hopping mechanism was. The drawback was that a reliable method had to be sought for ensuring that both the transmitter and receiver were synchronised so that the transmitted signal could be received at the remote end. Antheil's contribution was in proposing a method by which this could be achieved. The concept was to use paper rolls similar to the piano player rolls that were used for pianolas.

The two worked on the idea for several months before sending a description of the concept to the National Inventions Council. According to Antheil, the director of the council suggested that he and Hedy Lamarr should develop the idea to a point where it could be patented. Enlisting the help of an electrical engineer continued their development to a point where it was operational. As in Antheil's original suggestion it used slotted paper rolls to provide synchronization of the frequency changes at the transmitter and receiver. Reflecting Antheil's musical background there were eighty-eight frequencies, the number of keys on a piano.

The two applied for the patent. Patent number 2,292,387 was granted on 11th August 1941 under her married name Hedy Kiesler Markey, along with co-inventor George Antheil, as a "Secret Communication System". The name Markey was that of the second of six of Hedy Lamarr's husbands.

The patent also specified that a high-altitude observation plane could be used to steer a torpedo. This invention was the first instance of spread-spectrum communications based on frequency-hopping techniques.

Applying the idea

Gaining the patent was the easiest step of the development. It proved to be far harder to win support for its use, despite the requirements of the war. Antheil lobbied for support with the Navy, but the Navy did not want to place precious resource in developing it. They thought that the mechanism would be too bulky to accommodate within a torpedo. Meanwhile Hedy Lamarr demonstrated her loyalty to the USA by raising seven million dollars selling war bonds.

Having exhausted all the avenues they could pursue to get their idea implemented, there was no more they could do and the idea was left dormant. However in 1957, engineers at Sylvania reused the basic idea, but rather than employing paper rolls to provide the synchronization, they used electronic circuitry. It was first put to real use in the blockade of Cuba in 1962, about three years after the patent had expired. Although this meant that Hedy Lamarr and George Antheil did not receive any money for their idea, subsequent patents have usually referred to the Lamarr-Antheil patent as the basis of their work. In this way they at least have some recognition for their ground breaking work. Now the concept is used as the basis of many military communications schemes where the hopping is used to prevent jamming. It is also used in cellular systems including GSM to reduce the effects of interference and in some wireless systems for the same reason.

Lamarr's final years

During her life Hedy Lamarr married a total of six times and she had three children Anthony (b. 1947), Denise (b. 1945), and James (b. 1939). She also sued Mel Brooks for mocking her name in his film Blazing Saddles (1974). They settled out of court. She further sued the Corel Corporation in 1998 for using her photo on the cover of software product CorelDRAW.

Hedy Lamarr died in January 2000 aged 86 in a modest home in Florida. During her life she was quoted as saying "Any girl can be glamorous. All you have to do is stand still and look stupid." While she was certainly glamorous, as proven by her invention, she was most certainly not stupid.

More Famous Scientists in Electronics and Radio:
Volta     Ampere     Armstrong     Appleton     Babbage     Bardeen     Brattain     Edison     Faraday     R A Fessenden     Fleming     Heaviside     Hertz     Ohm     Oersted     Gauss     Hedy Lamarr     Lodge     Marconi     Maxwell     Morse     H J Round     Shockley     Tesla    
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