Not Just a Pretty Face
During WWII German U-boats could easily block radio transmissions between warships and torpedoes. The way that their submarines would “jam” the signals was to intercept a certain radio frequency and fill the channel with noise. Once the signal was lost, the torpedo would go off course and miss its target.
At the time, Hedy Lamarr was known for her beauty on the silver screen. Born in Austria after the first world war, she escaped her marriage to an Austrian ammunition manufacturer, who supplied the Nazi’s. She convinced Louis B Mayer to take her on as one of his stars and moved to Hollywood.
Hedy’s incredible beauty kept her well known as a leading lady, acting alongside some of the greats of old Hollywood. But secretly Hedy fed her secret passion. Growing up she was always tinkering away and making things. She had an “inventing table” so that she could work on her inventions in her spare time.
She was great friends with Howard Hughes, who wanted to make a faster aeroplane. Hedy, as she told the story, looked at a book of fish and birds and found the fastest fish and the fastest bird. She combined the two into a new, aerodynamic design, which she gave to Hughes.
When Hedy learned about the problem with torpedoes and signal jamming, she and her composer friend, George Antheil, came up with an ingenious solution. Hedy had the idea that if the radio frequencies could be changed regularly and quickly, they could not be jammed.
The only remaining problem was that both the ship and the torpedo would have to know which frequencies would be used and when. Inspired by George’s musical background, they thought of the player pianos of the time, which could automatically play a tune without a human seated at the keys. The music is loaded into the piano via a sort of “punch card” with the notes to be played.
Hedy and George realised that they could “play” the radio frequencies in the same order on both the ship and the torpedo, provided they both start at the same time. Hedy filed for and received a patent for the idea in 1942. Nothing came of their patent, and the idea was never used during the war. The patent document is impressively detailed and offers a fascinating glimpse into Hedy’s thinking.
This “frequency hopping” concept formed the basis of what we call “spread spectrum” today. Hedy was never compensated for her idea, even though today it’s used in most wireless transmission systems including Bluetooth and WiFi.
Hedy had to find other ways to contribute to the war effort and became involved in war bond sales, using her looks to entice buyers. She reckoned she raised at least 3.5 million dollars worth of bonds.
Tragically, Hedy became a recluse in her later life, perhaps due to botched plastic surgery procedures. In 1990 Hedy gave an interview to a journalist, in which she spoke about her inventions for the first time.
At the end of her life she wrote a letter to her son in which she quoted the poem:
Give the world the best you have and you’ll get kicked in the teeth.
Give the world the best you have anyway.”― Kent M. Keith as quoted in this article
A lot of the information for this short article came from the brilliant movie “Bombshell: The Hedy Lamarr Story” which did a lot to uncover the unknown parts of her life. I highly recommend it if you’d like to find out more about her life and work.
This article is part of a series of stories about the history of women in tech I’m writing in preparation for my talk at DevConf 2019. See my previous post in the series.
