Hedy Lamarr and Frequency Hopping

There are many great stories in telecommunications but Hedy Lamarr's is my favorite. She is truly a hero in modern day telecom.


Many of the wireless technologies used today for security and bandwidth efficiency can be traced back to an invention Hedy Lamarr patented during World War II. If you are using Bluetooth, a WiFi hotspot, a cordless phone, a mobile phone on the Verizon network, a wireless mouse, keyboard, printer or fax, than you are using this technology.

Despite leaving school at 16 she was a brilliant mathematician and innovator, but her beauty and talent lead her to a career as a film actress. She was from Austria and married young to an overbearing arms manufacturer. Upset by her scandalous films he would keep his young bride close to him at technological meetings and parties he hosted which included guests such as Hitler and Mussolini. It was here that she picked up many of her technical skills but the Jewish actress had a lot of distaste for her husband and his friends.


As legend has it, one night she drugged her husband, disguised herself as a maid and escaped to Paris for a divorce. Eventually she made her way to London and was discovered by Louis B. Mayer and the rest is film history. But we are here to discuss telecommunications history.


During World War II, Hedy wanted to funnel her hatred of Hitler to more than selling war bonds. From her husband's meetings she knew that radio guided torpedoes and missiles were easily jammed by the enemy. Working with composer George Antheil they developed a method of changing frequencies so sender and receiver both knew what frequency the message is broadcast at.


It works like this. Imagine you are in a car listening to a radio broadcast that is meant just for you. The DJ is going to broadcast portions of the program on one frequency, then on another, then on another. Only you and the DJ know the frequency sequence. As you listen you change the frequency on the dial of your radio in the order the DJ told you and you get all the messages sent. Anyone else listening will hear a portion of the message but will have no idea where to change their dial to receive the remaining messages. It would make no sense to them. This is termed "frequency hopping" in telecommunications.


In 1942 Hedy and George Antheil were granted patent number 2,292,387 for their "Secret Communication System". Sadly the idea was so far ahead of it's time that the patent ran out before Hedy or George Antheil's revolutionary idea was put to use. In the late 1950's government contractors researching old patents stumbled upon the Secret Communication System. With the technology of the time they used this information for torpedo guidance systems and other "spread spectrum" communications. Later frequency hopping was no longer a government secret and was utilized for wireless telecommunication systems in several different forms. With the patent expired Hedy and Antheil never made a dime on their invention. In 1997 Hedy was finally recognized for her contribution and won the EFF Pioneer award for her innovative technique. She passed away three years later.