This is the continuation of a story begun on our July 2015 Home Page. To
go to an archived version of that page, click here: July
2015 Home Page Archive. To return to this
month'sactual Home Page, click on the Signal Corps
orangeHome Page menu item in the
upper left corner of this page.
What was her strong suit, you ask?
Intelligence was her strong suit. For one, she spoke nine languages. Besides German, the languages she spoke included Hebrew, Yiddish, Latin, Italian, Hungarian (taught to her by Eva Gabor), French (taught to her by Charles Boyer), Dutch and English. For another, while a high school dropout, she was an autodidact, immersing herself in every form of science, mathematics and technology she could get her hands on.
To supplement her thirst for knowledge, she made as her friends men of intellect… physicists, mathematicians, engineers, and most importantly, the kind of men who at that time were trying to make a profession out of the use and application of technology that fit within the broad category of radio communication and electronics. A new field of study, in the late 30s and early 40s radio communication and electronics looked as though they might revolutionize the world—spawning inventions that would make everyone’s life easier and happier.
To Hedy this was… well… heady stuff. Determined to build her economic foundation on something other than her looks, she partnered with a number of men, to try to invent and develop applications that applied these forms of technology to the problems of the times.
Strange as it may seem, Hedy spent much of her time looking for real world problems that she could solve via the use and application of radio and electronics technology. By “real world,” we mean those kinds of problems the solution for which could actually change the world. We’re not talking here of inventing a new type of Austrian dessert, or a better French roll… but inventing new kinds of propulsion system, forms of electronic communication, command and control systems, and most importantly… weapons systems.
For Hedy Lamarr, her quest to find a way to apply science to world problems was real. After all, having come from Austria she knew well the turmoil the Third Reich was bringing to Central Europe. While she enjoyed the smart lifestyle of a Hollywood celebrity, she knew well that at that time, in 1940, her family and friends back home in Austria were living through the hell of the start of World War Two. England and Germany were locked in combat, Poland was being subsumed by the Reich, Jews were being rounded up and sent off to God knows where, and the world was turning upside down.
Hedy knew the strength behind the German war machine, and she knew that if it was to be defeated more than just manpower and good ideas about better ways to politically run a country were needed. That is, yes, it was necessary to throw men onto the battlefield if Hitler was to be defeated, and yes, it was necessary once he was defeated for there to be a better way to run the country of Germany, if future wars were to be avoided… but none of this would come to pass if the only thing the world had with which to defeat him were men in uniform.
Something else was needed, something that would give these men a superiority over those they fought. If not, then in her view it was likely that WWII would degenerate into just another WWI… a struggle where men slugged it out against other men, in trench warfare, until both sides bled to death.
What was needed was a way to bring technology to the side of good; technology able to leverage the strength of the fighting men America was sending to Europe… and Asia.
All of this came home to roost in Hedi’s mind one night when she sat at dinner with her husband and a group of his business friends. Married 6 (yes, six) times, Hedi spent many nights with many husbands at dinner, with friends. She also spent many days sitting in conference rooms at her husbands' offices, as she was want to do as a means to involve herself in their businesses.
Her first husband she married at 19. A good choice, he was at the time the third-wealthiest man in Austria, having made his money in politically connected arms manufacture and sales. It was with this man, Baron Fritz Mandl, that Hedy got her first look at how military arms were designed and made. While Fritz spent his time and hundreds of thousands of dollars trying to suppress prints of his wife’s film, Ecstasy, she spent her time learning how business worked, and how decisions were made at the highest levels, in Board Rooms.
Her fascination was with the decision making processes that drove business, and so she spent endless hours not just sitting in Board Rooms with her husband(s), but also quietly eavesdropping on the conversations of important men she met in those Board Rooms and at dinner parties. Principally focused on technology, she made mental notes of control systems and how they worked, as well as arms secrets openly discussed in her presence. After all, she was just another pretty face hanging on the arm of just another rich man… she couldn’t possibly have any idea what these important men were talking about now, could she?
Eventually her marriage with Baron Mandl failed, and Hedy moved on to another husband. With her however she took not only the knowledge she had gained about how military arms were designed and manufactured, but also an undying passion to be involved in business, and the high technology arms business in particular.
In the early part of WWII German U-boats wreaked havoc on Allied shipping. When America finally joined the war, in 1941, it assumed the same posture by bringing submarine warfare to both the Nazis and the Japanese. Initially, little if anything could be done by either side to counteract the success radio guided torpedoes were having in chasing down their target. But that didn’t last long. By mid 1941 Germany, Japan and America each all recognized that radio guided torpedoes had one drawback: their control frequencies could be jammed. It wasn’t long thereafter before torpedo jamming radars were being deployed on the vessels of all sides.
The U.S. Navy in particular worried that this simple torpedo countermeasure would make their underwater submarine fleet next to useless in the long war ahead, and looked frantically for a solution to the problem. To their rescue came the Signal Corps, who ramped up research on means to defeat frequency jamming in hopes of returning the torpedo to the ranks of a nearly perfect weapon system, for naval use.
Unbeknownst to many, the principle upon which the Signal Corps developed both a means to “encrypt” communication and keep it from being jammed (as was needed to stop radio guided torpedoes from having their frequency scrambled and jammed), or decoded as in the case of someone listening in on a radio transmission, was based on a concept that Hedy Lamarr first articulated and patented.
The concept is known today as Frequency Hopping Spread Spectrum (FHSS), and it is a method used to transmit radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both the transmitter and the receiver. Today it finds its greatest use as a multiple access method in the frequency-hopping code division multiple access (FH-CDMA) wireless technology scheme that underlies cell phone usage.
For the uninitiated, FHSS is radio transmitted and therefore is composed of a wireless technology that spreads its signal over a number of rapidly changing frequencies. Each available frequency (band) is subdivided into even more sub-frequencies. Signals rapidly change ("hop") among these frequencies in a coordinated and synchronized order. Because of this, interference (such as radio jamming) at a specific frequency will only affect the base signal being transmitted during that microsecond interval during which that frequency is being used. With frequency hopping then, radio interference can be minimalized to the point of negation… which in the case of a torpedo, allows the thing to go along its merry way toward the target it is being sent to destroy.
Hedy Lamarr invented this concept, almost as an afterthought, during one of her and her then husband’s dinner soirees. Listening in on discussions arms merchants were having about radio jamming problems undermining both the value and usefulness of the torpedoes they were selling; and listening to navy men at the table crying out for development of a torpedo that could not be jammed, she turned to her associate, George Antheil, and asked why their earlier discussions of the “player piano concept" could not be used to solve this problem. She made her case to him that what they termed the player piano radio communication concept would prevent the signals controlling the torpedo from being jammed. He gave the idea a few seconds of thought, and replied to her that she was exactly right... the concept would work.
As to who George Antheil was, he was both a musician and an inveterate tinkerer. In those days he was famous for composing and presenting on stage an avant-garde symphony that used several dozen player pianos, all of which were synchronized to play the exact same song. His idea was eventually brought to the big screen in a movie that showed dozens of beautiful girls sitting at multiple pianos, all playing the same concert, while the camera floated among them, focusing on their charms. Behind the scenes however, the girls were not actually playing the pianos that lined the stage, George's player piano synchronization system was.
Hedy applied, in her mind, the same concept to radio communication, except that in her mind she replaced the 88 notes that needed to be synchronized on a piano with 88 different radio frequencies. Then, using... in her mind... a mechanical coupling mechanism similar to that of a piano player roll, the signal being transmitted would be shifted among the 88 available frequencies. The pattern of shift, and the frequency to which the signal would be shifted, could be as random as the notes in any song. In essence then, her idea was that if pianos could be synchronized to hop from one note to another in playing a song, why couldn't radio signals? And why couldn’t this concept be used to guide a torpedo?
She termed the design a "Secret Communication System" and patented it. With that out of the way, she brought her idea to the U.S. Navy. The Navy brass promptly, and unceremoniously we might add, laughed them out of their office. “What,” they said, “you want to put a player piano in a torpedo?!”[1]
The Signal Corps however did not laugh at their suggestion. They got the point quickly, and began researching how to turn the concept into reality. In short order the Signal Corps had determined that spread-spectrum transmission offered three main advantages over fixed-frequency transmission:
1. Spread-spectrum signals were...
and still are...
highly resistant to narrowband interference. The
process of re-collecting a spread signal spreads out
the interfering signal, causing it to recede into
the background.
2. Spread-spectrum signals are
difficult to intercept. A spread-spectrum signal may
simply appear as an increase in the background noise
to a narrowband receiver. Because of this an
eavesdropper would have difficulty intercepting a
transmission in real time, if the pseudorandom
sequence is not known.
3. Spread-spectrum transmissions
can share a frequency band with many types of
conventional transmissions, with minimal
interference. In other words, spread-spectrum
signals add minimal noise to narrow-frequency
communications, and vice versa. As a result,
bandwidth can be used more efficiently.
From a military standpoint, what this meant was that spread-spectrum signals could be counted on to be highly resistant to deliberate jamming, unless the adversary had knowledge of the spreading characteristics. Today this has led to military radios using spread-spectrum signals, where the transmission is governed by cryptographic techniques employed to generate the channel sequence, and where the technique is under the control of a secret Transmission Security Key (TRANSEC) that the sender and receiver can share in advance.
And to think that all of this was started by Hedy Lamarr.
Yet while all of this was fine for the form of communications used back during WWII, today's sophisticated digital frequency mapping techniques call for more robust measures, if signal jamming or tracking is to be avoided. Because of this, additional countermeasures are used to foil modern computer mapping techniques, since as it stands today, frequency hopping provides only limited protection against eavesdropping and jamming. As a result, most modern military frequency hopping radios employ a separate, stand alone encryption device, such as that found in the KY-57. Today U.S. military radios that use frequency hopping include the JTIDS/MIDS family, HAVE QUICK and SINCGARS… all thanks to the brains behind the beauty of Ms. Hedy Lamarr.
As for Hedy, she and Antheil believed so strongly in their idea that in 1942 they patented it. In their patent one can see the influence of the player piano concept, as the number of frequencies to be “hopped” counted out to exactly 88… the same number as the number of keys on a piano.[2]
The Signal Corps on the other hand took to the concept like a fish to water. Research progressed on FHSS, with it eventually finding its way into numerous military command and control systems. As those who follow this website know, during World War II the US Army Signal Corps invented a communication system which incorporated spread spectrum transmission in a single frequency context. It was called SIGSALY. Donald Mehl, an expert on the science behind the technology of spread spectrum, and a graduate of Army Signal OCS Class 44-35, wrote a book on the topic. He named his book Top Secret Communications of WWII, and it is available at our website's PX store. We reviewed it in our in June 2012 publication. Don also penned an article called Surrender On The Air, in which he exposed the real story behind Japan's surrender, and the role SIGSALY and the Signal Corps played in it. That article we posted on our July 2012 Home Page.
Whether the invention of SIGSALY stemmed from the information Hedy Lamarr passed on to the Signal Corps at Fort Monmouth or not will likely never be known, as the overall SIGSALY program was classified as top secret and remained so up until only recently. Finding documents and files from back then that might cover this topic would be hard to do. Still, it is fascinating to note that research on Hedy's FHSS method was being conducted at Fort Monmouth at the exact same time that the use of spread spectrum, single frequency technology was being developed for use in SIGSALY. In our view, that's enough for us to credit SIGSALY to Ms. Lamarr... and if we are wrong, then let others prove it so. Regardless, there is no doubt that Ms. Lamarr’s frequency hopping method was being bandied about the research halls of the U.S. Army Signal Corps at Fort Monmouth, New Jersey, at the exact same time that SIGSALY was being developed.
Carrying this line of thought further, there were other technical problems being looked into at Monmouth at the same time that SIGSALY was being developed, and interestingly they too show signs of use of Ms. Lamarr's FHSS concept as a means to solve their problems. One of these involved finding a way to make FHSS more reliable by developing a means for frequency-hopping systems to synchronize the transmitter and receiver.
One approach developed at Monmouth to assure synchronization involved creating a way to “guarantee” that the transmitter would use all of the channels (frequencies) available to it, within a fixed period of time. If one thinks in terms of a player piano roll, and a song stamped onto it that uses all 88 piano keys, it is easy to see that the length of the roll, the pre-set stamping of the air-holes (on the paper roll) that determine the key sequence, and the mechanical adjustment that sets the meter for the song, as well as the number of specific keys used, all work to force the piano to "transmit" the sound desired within the prescribed time signature and meter of the song (e.g. two beats to the bar, etc.), in the prescribed pattern. In other words, the mechanics of the piano roll system force a synchronization process to take place.
What the boys at Monmouth appear to have done was simply replicate this mechanical approach to synchronization in the form of an electronic one. That is, the same five mechanical control factors used in the piano roll construct were built into electronic circuitry that forced the signal being transmitted to cycle through all of the frequencies available. This they likely did via use of RC time constants to controlled frequency shifts during transmission and reception, such that the frequencies being transmitted were selected based on a preset "metering" that was wired into the transmitter.
By using this method the receiver could then be assured of finding the transmitting frequency by randomly picking channels and listening for valid data on that channel. The transmitter’s data (versus random noise) could be identified by an embedded code that represented a special sequence of data unlikely to occur over any other segment of data for the channel in question. This form of checksum integrity identification would in turn assure the synchronicity of the communication exchange. Via this method, the transmitter and receiver could use fixed tables of channel sequences so that once synchronized they could continue to maintain communication, by following the table. On each channel segment, the transmitter could then send its current location in the table, which the receiving station would pick up and use as a guide for the next signal (frequency) to be received.
Later, as this entire area of technology developed far past what was known during WWII, it was found that in a multipoint radio system the space that existed between frequencies could be used to allow multiple transmissions on the same frequency, thus enabling the use of multiple radios in a single, closely held geographic area. This in turn created the possibility of system data rates that would be much higher than the expected Shannon limit for a single channel. As Signal Corps research was able to show, spread spectrum systems of this type do not violate the Shannon limit. Further, even later Signal Corps research found that spread spectrum systems could in fact rely on excess signal to noise ratios for the sharing of the available spectrum. Today this property can be found in both MIMO and DSSS systems. Finally, the Signal Corps also perfected the concept of beam steering and directional antennas, in order to improve system performance by providing isolation between remote radios.
And all of this from a mathematical formulation that came out of the head of one of America’s most beautiful women. Who would have thought?
As to the practicality of Hedy Lamarr’s FHSS invention, perhaps its first most famous use came about in 1962, during the Cuban Missile Crisis, an event that occurred some twenty years after Hedy received her patent, and 3 years after the patent had already expired. Because of fears that Khrushchev would take Castro's advice and wage war on the U.S. Navy ships that blockaded his island, the Navy hastily installed frequency hopping encryption communication systems on the vessels it sent to Cuban waters, as well as FHSS guided torpedo systems. It’s interesting to note then that the very same U.S. Navy that 20 years earlier laughed at Hedy when she first tried to help them, were now turning to her solution as a means of keeping their precious ships afloat and safe from the potential of USSR launched torpedoes.
Today her legacy continues, with practical applications of her design being used as the basis for secure digital radio-teletype methods, missile guidance systems, within the Air Force’s “Phantom” radio system, to provide reliable navigation systems, and for multiple other uses relating to secure voice and data communication.
Equally important are its uses in the civilian sphere, where FCC authorized use of FHSS techniques led to the use of spread spectrum communication within ISM bands, which in turn led to the development of cordless phones, Bluetooth, GPS, wireless cash registers, RFID systems, and today’s ever important and necessary WiFi.
The next time you find yourself walking the street, your SmartPhone to your nose, search for a WiFi signal, think of Hedy Lamarr… picture her beauty, and tip your hat to her even more beautiful brain.
Hedy Lamarr, a Signal Corps Sweetheart if there ever was one.
Footnotes:
[1] Quotation sourced from NPR,
Remembering Hedy Lamarr: Actress,
Weapons Systems Developer, November 9,
2014.
- To return to your place above, click
here.
[2]
The method received U.S. patent
number 2,292,387 on Aug. 11, 1942, under
the name "Secret Communications System."
In the patent Hedy, who was just 26 at
the time, used her then married name of
Hedy Keisler Markey. Still believing
that her concept had value, Hedy quietly
signed her patent over to the U.S. Navy, who promptly ignored it. For the
good of her new country, she gave the technology away and never asked for
nor made a penny off of it. - To return to your place above, click
here.
Additional Sources:
Website entitled This Recording; online blog; content extracted from
an article entitled “In Which Hedy Lamarr Refuses
To Stand Still And Look Stupid”,
Blog originally posted Monday,
April 2, 2012, at 9:41AM.
Frequency Hopping Spread Spectrum (FHSS) vs. Direct Sequence Spread
Spectrum (DSSS) in Broadband Wireless Access (BWA) and Wireless LAN (WLAN),
author Sorin M. Schwartz.
Like this article? Let
us know by helping us with our scholarship fund efforts. A $30.00 donation
to our Scholarship Fund
will help us get one step closer to helping another deserving High School
graduate attend college. Your donation is tax deductible and your kindness
will go father than you think in making
it possible for another young American to fulfill their dream of a college
education. Thank You!
Original Site Design and Construction
By John Hart, Class 07-66. Ongoing site design and
maintenance
courtesy Class 09-67.
Content and design Copyright
1998 - 2015 by ArmySignalOCS.com.