Spread-Spectrum radio communications, long a favorite
wireless technology of the military, as it resists jamming and is hard for anyone
trying to capture its message content. Today, spread-spectrum is also found on
the commercial wireless industry.
Spread-spectrum signals are randomly coded and distributed over
a wide range of frequencies, then reassembled onto their original frequency at a
receiver. Just as these signals are
unlikely to be intercepted by an enemy, so are they unlikely to interfere with
other signals intended for consumer wireless devices. There are two major types
of spread spectrum: direct sequence and
frequency hopping. Spread Spectrum is ubiquitous,
as it is found in Satellites, Cellular, Bluetooth and Wi-Fi wireless technology.
This technology was invented in the early 1940’s, initially
the US experimented with spread spectrum for communication countermeasures,
radar, and navigation beacons.
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| Hedy Lamarr |
A 19-year-old young lady from Vienna, Austria, who in 1933 married
a millionaire and a Nazi sympathizer, is responsible for this wireless technology. Her husband, Friz Mandl and his family, were munitions
manufacturers and arms dealers. As the
Mandl family was involved in arms, they had contacts with the highest levels of
the people controlling Germany and Italy, both Benito Mussolini and Adolf Hitler
attended Mandl's parties.
During her four-year marriage to Mandl, this young lady learned
and studied weaponry by going on business trips with her husband, learning and listening
to discussions regarding all kinds of weaponry and their control systems.
Eventually, her disgust for the Nazis and a controlling and
abusive husband, she disguised herself as a maid and escaped to Paris, where she got a
divorce.
This young lady’s name was Hedwig Eva Maria Kiesler Mandl,
she was born in 1914. Hedwig eventually met MGM’s Louis B. Mayer in London, who
brought her to Hollywood and gave her a movie contract and a new name – Hedy
Lamarr.
CBS news once stated that Hedy Lamarr “possessed the kind of beauty that was haunting - an almost smoldering
sensuality, with an exotic accent to match. She was once dubbed "the most
beautiful woman in the world". Hedy
had a great deal of fame and fortune, as she appeared in about 30 movies over a
20-year period.
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| Lamarr "the most beautiful woman in the world" |
After her first US movie; one viewer stated that when her
face first appeared on the screen, "everyone gasped...Lamarr's beauty
literally took one's breath away”
The intellectual side of Lamarr was not known or understood
until later in her life.
At home, Lamarr had a comprehensive library of math and engineering
reference books, a drafting table and tools where she spent time analyzing
engineering problems. What was a
Hollywood star doing inventing electrical engineering circuits?
In 1940 she met George Antheil, an American composer,
pianist, author, inventor, electrical, mechanical music entrepreneur, and also
an “expert” on female endocrinology where she was seeking his help on improving
her upper torso. They soon found that
they had more in common - torpedoes.
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| George Antheil |
With her knowledge of torpedoes learned while married to
Mandl, she knew that a single radio controlled torpedo could easily be detected
and jammed, by transmitting interference at the frequency of the signal that
causes the torpedo to go off course.
With their common interest in torpedoes, Lamarr and Antheil
developed the idea of using frequency hopping.
Their collaboration resulted in using a piano for coding. A piano “roll” was used to randomly change
the wireless signal sent to the torpedo by sending short bursts of 88
frequencies in the spectrum; note there are 88 black and white keys on a piano
keyboard.
This scenario basically made it impossible for the enemy to
find and jam all 88 frequencies. Antheil would control the frequency-hopping
sequence [coding] by using a player-piano mechanism, which he had used in his “Ballet
Mécanique”.
A player-piano is a self-playing piano that uses perforated
paper, where pre-programmed music
is recorded – in this case the piano roll.
In 1942, after initial failure and rejection from the US
Patent Office, Hedy and Antheil were granted a patent for their “secret”
communication systems. The patent was
under the name of Hedy Keisler Markey, which was her married name at the time. Hedy's idea was if you could make both the
transmitter and the receiver simultaneously jump from frequency to frequency, then
someone trying to jam the signal wouldn't know where the signal was – secure
communications utilizing frequency hoping.
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| Lamarr-Antheil Spread-Spectrum Patent |
Lamarr was involved in the war effort by promoting war
bonds. She stated “I’m still determined
to help the war effort with or without my torpedo invention, I will be offering
a kiss to anyone who donates $25,000 in war bonds - come out and support the
fight against Hitler”.
Hedy quietly signed her patent over to the Navy. Like other
wireless inventors, she gave the technology away, and never made a dime off of it. Others took the technology and
improved on it, as well as the credit for it.
In an autobiography, Antheil gives full credit to Lamarr for the
invention of spread-spectrum technology.
In 1953, Lamarr became a U.S. citizen. In her later
years, she lived a reclusive life in Orlando, FL. It took more than 50 years for Hedy to receive
credit for her invention. During her lifetime, she was given awards but never
showed up to received them.
Lamarr died on January 19, 2000, she was 86.
In 2014, Hedy Lamarr was inducted into the National
Inventors Hall of Fame.
