Celebrity Invention: Hedy Lamarr's Secret Communications System

patentsrichfamous_280(2).jpgSome celebrities aren't just pretty faces. A few of them are also touched with that Yankee prowess for tinkering and invention. In this weekly series, we introduce you to the Patents of the Rich and Famous.

Inventor: Hedy Kiesler Marky aka Hedy Lamarr

With a face like that and a name like Hedy, Lamarr used her assets to pursue a lucrative acting career. She began with her controversial appearance in Ecstasy, a 1933 film featuring a naked Ms. Lamarr (scandal!) and eventually went on to conquer Hollywood. She worked as MGM's beauty, starring in loads of films, including the highest grossing movie of 1949: Samson and Delilah.

But don't let her pretty veneer fool you, Lamarr offered more than her insane good looks and equally impressive acting talents. While married to her first husband -- Friedrich Mandle, an arms manufacturer -- she learned about military technology, as he forced her to attend meetings with technicians and business partners. Later she would use this knowledge to create her apparatus to help the American war effort.

Invented Apparatus: "Secret Communications System"


Lamarr and her co-inventor, avant garde composer George Anthiel, figured out how to use the mechanics of the player piano to create the earliest version of the "frequency-hopping spread-spectrum" system. It's a method that protects radio communications from enemy snoops by switching frequencies in a preprogrammed pattern. Both the sender and receiver know the order of switches, so they can maintain constant connection while losing the bad guys.

Lamarr's invention envisioned a torpedo and a guidance transmitter equipped with identical player piano sheets that run along a simultaneous pseudo-random sequence. Without knowing the exact pattern of the frequency hops, the enemy cannot interpret the signal, meaning Lamarr's torpedo has much better security.

Briefly, our system as adapted for radio control of a remote craft, employs a pair of synchronous records, one at the transmitting station and one at the receiving station, which change the tuning of the transmitting and receiving apparatus from time to time, so that without knowledge of the records an enemy would be unable to determine at what frequency a controlling impulse would be sent.

Furthermore we contemplate employing record of the type used for many years in player pianos, and which consist of long rolls of paper having perforations variously positioned in a plurality of longitudinal rows along the records. In a conventional player piano record there may be 88 rows of perforations, and in our system such a record would permit the use of 88 different carrier frequencies, from one to another of which both the transmitting and receiving station would be changed at intervals. Furthermore, records of the type described can be made of substantial length and may be driven slow or fast. This makes it possible for a pair of records, one at a the transmitting station and one at the receiving station to run for a length of time ample for the remote control of a device such as a torpedo.

Or as Ian Akyildiz, an electrical and computer engineering professor at Georga Tech, explained to us it goes something like this:

Suppose you're sending something on channel five. When an intruder finds out that you're sending the entire information on channel five, then he or she can take everything you are sending off channel 5 and reconstruct it. But, when you hop around, the intruder cannot capture this hopping, and he cannot reconstruct the information. So from the security perspective it is perfect.

Rationale Behind Invention:

An object of the invention is to provide a method of secret communication which is relatively simple and reliable in operation, but at the same time is difficult to discover or decipher.

A Jewish immigrant from Vienna, Lamarr was down to defeat the Nazis. She hoped that the technology would better guide ally torpedoes aimed at Germans. Unfortunately, the U.S. Navy ignored the innovation, claiming that a player piano could never fit inside a torpedo, even though Anthiel explained that they had only used a player piano as an example -- the parts in fact could be made small enough for the torpedo:. " 'My god,'" he sighed, "I can see them saying, 'We shall put a player piano in a torpedo.'"

Of course, several other inventors had their own takes on frequency hopping and eventually the U.S. government got with the program. In 1962, the U.S. army recognized Lamarr's genius, using her invention in military ships against a Cuban blockade. Variations on the technology are now standard. Heard of CDMA cell phone networks like those that Sprint and Verizon run? They work a lot like the "secret communications system" Lamarr and Anthiel envisioned.

Off Label Uses:

Let's be honest, who doesn't need a secret communications system?

Future Directions:

Lamarr was the kind of icon that drew the attention of Andy Warhol, who made a movie about her nasty shoplifting and man-discarding habits in which she testifies against her five ex-husbands. As a bonus, The Velvet Underground performs live. So she might appreciate a reversal of her work as an art installation. In it, a drone's movements over Afghanistan would control an actual musical player piano that would shift octaves whenever a frequency hop was made, cuing us in that security was being maintained.

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