Hedy Lamarr: Skipping in Sync
- Venika Kasva
- 5 days ago
- 7 min read
How a Hollywood actress invented a secure signal sender.
Did you know that a famous Hollywood actress created the foundation for the technology behind WiFi and Bluetooth? This starlet was named Hedy Lamarr, and she was one of the 1950’s most famous actresses. But how does someone who is an actress also invent the basics of such a powerful technology? Who was this mysterious woman really?
The Rise to Stardom
Hedy Lamarr, born as Hedwig Eva Kiesler, was born in Austria on November 9, 1914. She was the only child in a wealthy Jewish family. Hedy was privately tutored from the age of 4, and could speak 4 languages at age 10! She and her father, a bank director, often took walks and discussed the inner workings of machines. This fostered her curiosity in inventions, and she once took apart her mother’s music box to see how the insides worked. Her mother encouraged Hedy to excel in the arts, as well, and she attended ballet and piano lessons from a young age.
When Hedy was 16, she was discovered by a famous director and started her acting career. And at age 18, she married her first husband, Fritz Mandl, an Austrian munitions dealer. Unfortunately, he was very controlling, and didn’t support her acting career. He was also connected to avid supporters of the Nazi party. Sick of this treatment, Hedy soon planned to escape. She successfully left her unhealthy marriage, and rebuilt her acting career in Hollywood.
Even as a famous Hollywood actress, Hedy never lost her interest in inventing new things. She even had an invention table in her movie set trailer so that she could work on new projects between filming takes! World War ll began around this time, and Hedy desperately wanted to help the war time efforts. She met a man named George Antheil at a dinner party; George was a music composer, inspired by piano and the arts, who also wanted to make an impact on the war and help the Allies.
This unlikely duo, an actress and a composer, worked together to devise an encryption system inspired by the mechanics of a piano.
Learning How to Hop
The US Navy had a problem. A lot of their strategy during World War II depended on tracking submarines and deploying torpedoes during battles at sea. They needed to guide torpedoes to specific targets. The problem was, an enemy could “jam”, or block, the signals used to guide torpedoes, making it impossible to reposition the torpedoes already in motion.
The signals were made of radio waves, which can be “jammed” by playing the same frequency, but encoded with nonsense messages. All the extra noise, due to radio waves of the same frequency, meant that the torpedo and the control systems could no longer decipher the messages encoded in the waves. They would only hear static.
What's a Radio Wave?
A wave is a pattern that travels from one location to another and carries energy with it. You might be familiar with ocean waves, The Wave at a sports stadium, or sound waves that move through the air. Another type of wave is the electromagnetic wave, or light! Electromagnetic waves are made of oscillations in both the electric and magnetic field, with each component perpendicular to each other and perpendicular to the direction of travel.
But the most important thing to know is that the wavelength of electromagnetic waves can be as small as an atom, or as big as a galaxy! Radio waves have the longest wavelengths of the entire spectrum; the largest ones being longer than a football field!
Electromagnetic waves, meaning light, can be used to look at stuff, which you’re probably pretty familiar with. Our eyes can see light in the visible range—meaning red through violet light—but we can’t see radio waves with long wavelengths, or x-rays with really short wavelengths. However, we can build devices that measure other parts of the electromagnetic spectrum, allowing us to observe the universe and all its planets, stars, and more!
Light waves can also be used to communicate. Waves have two main features: wavelength, and amplitude. Wavelength is how wide the wave stretches, and amplitude is how tall the wave gets. Frequency is another term used to describe waves. The frequency of a wave is how many wavelengths travel past a point per second, so the frequency is another way to describe the wavelength, and vice versa.
By modifying, or modulating, either frequency or amplitude of a wave, you can encode messages in the wave! This is where the names “FM” and “AM” radio come from—they tell you whether the wave you’re receiving is a frequency modulation or an amplitude modulation.
There are two common encoding methods that you’ve probably heard of: Morse code and binary. Both systems rely on two types of signals. Morse code uses a dash and a dot, and binary uses a 0 and a 1. By alternating dashes and dots or 0s and 1s, you can build an alphabet or even a computer program! Modulating the frequency or amplitude of a wave in specific ways can carry those dashes and dots or 0s and 1s.
Hedy Lamarr and George Antheil turned to pianos as an inspiration for a solution to the frequency-jamming problem. Pianos have 88 keys, each of which creates a different frequency sound wave. Their proposed invention allowed synchronized changes between 88 frequencies of radio waves, using a mechanism similar to player piano rolls.
Let’s see how this worked.
Say that you and your friend buy 20 flip phones. You don’t want anyone else to eavesdrop, so you decide on a predetermined order in which you will switch phones. So you’ll first call each other on phone #7, say 3 sentences, and then go to phone #2 and say the next 5 sentences. After that you’ve agree to call each other on phone #18 and speak for 2 sentences, and phone #13 for 15 sentences after that.
This would be a lot of trouble to go through, using cell phones for the sake of security, but this is exactly how frequency hopping works. The phones represent different frequencies that the sender and receiver synchronously switch between to communicate.
Lamarr and Antheil’s invention automated the synchronous switching, since both the sender and receiver would have the “piano roll” that dictates the switching pattern. This was an ingenious solution to the jamming problem—a signal can’t be jammed if only the sender and receiver know the frequency pattern! Using frequency-hopping would make interference a lot less common and ensure message interception was impossible.
Their system of frequency-hopping was patented in 1942, and the team presented it to the US Navy. The Navy didn’t see the full potential of Hedy and George’s invention, and didn’t end up using it. But several decades later, the idea became integral to technology like Wi-Fi and Bluetooth.
Lost and Found
The concept of frequency hopping was rediscovered by engineers at Sylvania Electronics Systems Division, who used transistors instead of the original clunky mechanism in the torpedoes. This technology was used in the Cuban Missile Crisis by the United States to prevent Soviet radio jamming. The concept of frequency hopping was then used to build the technology that powers Bluetooth and WiFi.
Standard Bluetooth and WiFi devices use frequencies in the GHz (giga hertz) range. Your WiFi router might sometimes say "2.4GHz", or you might have "5G" cell phone service. These signals are in the microwave band of light radiation (yes, the same microwaves that heat up your leftovers!), which are much shorter than radio waves, but still way too long to see with our eyes. The wavelength of the light that carries our internet is about 6 in (15 cm).
Hedy and George's invention would have allowed maybe one or two frequency hops per second. Modern devices connected to WiFi or Bluetooth can frequency hop hundreds of times each second! But it's still the same basic idea: both the sender and receiver follow the synchronized hopping pattern in order to maintain a secure connection.
Delayed Recognition
Hedy was awarded the Pioneer Award from the Electronic Frontier Foundation in 1997 and she also became the first woman to win the Invention Conventionś Bulbie Gnass Spirit of Achievement Award later in 1997, years after her patent was issued. She died in 2000, knowing that the world finally understood her invention. After her death, her contributions to technology have continued to be celebrated.
Hedy Lamarr was born in a time where women weren’t expected to be anything more than wives, mothers, or at most a pretty movie star. Yet she persevered, gaining fame for her acting accomplishments and movies. She preserved her passion for inventing and creative problem-solving, even though society never recognized her impressive technological ideas.
Hedy famously once said, “The brains of people are more interesting than the looks, I think.” Her collaborations with friends, pursuit of curiosity, and dedication to technology made it clear she truly valued the brains of her peers and colleagues.
Thankfully, with the rediscovery of her incredible thoughts and proposed inventions, the world can finally see just how interesting and special Hedy’s brain was, too.
Written by Venika Kasva
Illustrated portrait by Venika Kasva
Edited by Madelyn Leembruggen
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