Hedy Lamarr, A beatiful Mind

by Federico Peiretti


Versione italiana

“It’s not difficult to become a great seducer”, Hedy Lamarr used to say, “staying still and playing the bimbo is enough”.

The great Hollywood movie star, who had an irresistible gaze and was acclaimed as “the most beautiful woman of the world”, demolishes the cliché that beauty must necessarily be accompanied by stupidity.

Although on screen she played the bimbo, in real life, besides being very beautiful, she was also very intelligent. The fact that she is the only movie star who can boast a patent in such a difficult field as telecommunications proves it.

In order to reconstruct the story of her invention we have to go back to 1933, when after the success of Ecstasy -the scandalous film where she appeared naked, the first naked scene in a film shown in normal cinemas- she married a rich Austrian weapons manufacturer, Fritz Mandl. Hedy Lamarr had been born in Vienna in 1915 and her parents forced her to marry when she was only eighteen. She could hardly put up with a despotic husband who treated her as a slave and – Lamarr remembers – paraded her as a trophy in his many meetings with generals, arms dealers and specialists on that field. Confident that the beautiful Viennese would never be able to understand their technical conversations they talked freely in front of her.

Four years later, when Mandl started collaborating with the Nazis, Lamarr escaped to London. There she met Louis B. Mayer from MGM, who made it possible for her to go to Hollywood. But she didn’t forget what she had learnt while she was at the side of the first of her husbands, particularly the confidential talks about the research Mandl was carrying out in a very delicate field: long distance weapons control.

In practice it was a matter of being able to guide a missile or a torpedo towards its target in such a way that the enemy couldn’t intercept and cancel the signal. Sure enough, a simple radio signal of a given frequency could easily be identified and blocked. Therefore it was necessary to find a way to switch frequencies from moment to moment, so that the enemy received just an indecipherable background noise while the signal arrived loud and clear only to those transmitting and receiving it, provided they were conveniently synchronised.

Hedy Lamarr all’età di 9 anni

Lamarr thought that if these ideas she had heard in Vienna were conveniently developed, they could provide a crucial contribution in the war against Nazism, which she personally hated. Meeting George Antheil, the avant-garde composer, in 1941, made it possible for Lamarr to achieve the practical realisation of her project. One day Antheil was playing the piano and she was following him with her voice. It was obvious that despite the continuous variations they could understand each other perfectly. Wasn’t it possible – Lamarr wondered – to achieve a similar understanding of frequency changes in a torpedo’s radio control?

George Antheil

They started working together on this idea. In essence, the range of frequencies available was subdivided in 88 subfields, or channels, as many as keys a piano has. The transmission was made to bounce from channel to channel at regular intervals, but the channel sequence order (for instance: 25, 11, 54, 61, etc...) was to be kept secret and known only by the transmitter and the receiver. Obviously they had to be perfectly synchronised and use a precise mechanism that remembered the sequence of channels selected during each elementary time interval. Antheil found the solution to both problems by adopting a method similar to that of the punched paper rolls used to operate mechanic pianolas. After several months’ work they presented their project at the National Inventors Council, which issued them with a patent registered on 11 August 1942, Secret Communications System n. 2.292387.

A design from the Lamarr-Antheil’s patent

That’s how what’s today known as “spread spectrum” or “divided spectrum transmission” was born. But technology in the 40s was still unsuitable for putting this idea into practice. It was the period of the big thermionic valves and the transistor didn’t exist yet. The project didn’t arouse great enthusiasm. The Navy declared that it would have been too difficult to insert a synchronising device similar to that used in pianolas into every torpedo. When Lamarr insisted on moving to Washington and working on her invention at the National Inventors Council, the army replied that she would be much more useful in Hollywood, using her stardom appeal for collecting the funds necessary to finance the war. Thus Lamarr gave up her idea and went back to her femme fatale role. It’s been told that during the evenings organised by The Army she offered a kiss to those who underwrote bonds for at least twenty five thousand dollars, and that in this way she managed to collect seven million dollars in a single night.

Her idea was correct though, and its realisation became possible with electronic technology. In 1962 the new communication technique was adopted by the United States. It was the on-board communication technique used by all the ships involved in the Cuban blockade. The idea of subdividing a wide frequency field in several channels is not only useful in cryptography, but also when you want to divide the transmission resources among several broadcasts. It’s not only useful for military purposes, but today it’s also used in mobile phones and wireless internet connections. In recent years the United States patents office has registered as many as 1203 patents related to the “divided spectrum transmission”.

Hedy Lamarr in Ecstasy

Finally also Hedy Lamarr is getting the acknowledgement she deserves for her work. The Electronic Frontier Foundation has awarded her the “EFF Pioneer” prize for “the invention and development in 1942 of the original frequency hopping concept, from which the spread spectrum stems.” Last time the newspapers talked about her was because of a theft in a Los Angeles department store. Although she’s never earned any money for her invention, the scientific prize she’s now received must surely be a far more important acknowledgement than any Oscar for Hedy Lamarr, a nice revenge on the general who had confined her to “selling kisses”. Hedy Lamarr died on January 18, 2000, at the age of 86.

Federico Peiretti

On the web

For those who want to know more about the subject:




The prize awarded to the actress:

The Wired article regarding the prize:

Homage to Hedy Lamarr, her films and her invention:

A short video taken from Ecstasy:

Hedy Lamarr’s filmography and biography: