A sentence often circulates on the internet: "A Hollywood star invented Wi-Fi." There is a real story inside the sentence, but the sentence itself isn't true. Hedy Lamarr really is the holder of an important patent. In this post let's separate what that patent did, what it didn't do, and its real link to today's wireless technologies.
From Vienna to Hollywood, from Hollywood to the patent office
Hedy Lamarr was born in Vienna on November 9, 1914 (some sources say 1913) and became one of Hollywood's best-known faces in the late 1930s. According to Wikipedia, at the meetings of her former husband, who was involved in the arms trade, she learned that navies wanted to guide torpedoes by radio but that the enemy could scramble (jam) the signal.
She developed her idea with the composer George Antheil. Antheil had struggled to synchronize multiple automatic pianos (player pianos) for his piece "Ballet Mécanique". That experience sat at the heart of the pair's solution.
What exactly did the patent describe?
According to APS News, the pair filed their patent application on June 10, 1941 and the patent was granted on August 11, 1942. US patent 2,292,387 is titled "Secret Communication System" and is registered under Lamarr's legal name, Hedy Kiesler Markey.
The idea was this: the transmitter on the ship and the receiver in the torpedo would send and receive the guidance signal not on a single frequency but on constantly changing frequencies. Even if the enemy found and jammed one frequency, the signal would already have hopped to another. To make the hops happen at both ends at the same time, according to the Smithsonian, a two-motor strip similar to a player piano roll was to be used. The system hopped among as many frequencies as there are keys on a piano, that is, 88.
Where the myth needs correcting
There are two important corrections here.
First, the idea of frequency hopping existed before Lamarr and Antheil. APS News stresses that it was "not an entirely new concept" and points to Nikola Tesla's 1900 and 1903 patents, a 1920 "secret communication system" patent, and patents granted to two German engineers in 1939 and 1940. Lamarr and Antheil's contribution was to turn the idea into a concrete, mechanically synchronized system for torpedo guidance.
Second, today's Wi-Fi didn't derive directly from this patent. Even the Smithsonian writes that it is "impossible to know exactly how much Lamarr and Antheil's invention influenced the development of this technology". Similar systems, according to APS, were worked on in 1957 with Sylvania's transistor-based efforts, and according to Wikipedia were first used operationally in 1962.
The real link to Wi-Fi and Bluetooth
Lamarr's patent is an early example of a broad family of techniques called "spread spectrum". One branch of this family, frequency-hopping spread spectrum (FHSS), really does live on in today's wireless devices:
- Classic Bluetooth typically hops 1,600 times per second among 79 channels.
- The first IEEE 802.11 (the standard that is the ancestor of Wi-Fi), published in 1997, offered speeds of 1 and 2 Mbit/s in the 2.4 GHz band and included frequency hopping as one of its physical layer options.
So the right sentence might be: Lamarr is one of the pioneers of the frequency-hopping idea used today in Bluetooth and the first Wi-Fi versions. Wikipedia too draws this link specifically for "early versions of Bluetooth and Wi-Fi"; moreover, the first standard included direct-sequence spread spectrum (DSSS) alongside frequency hopping. That's why saying "Lamarr invented Wi-Fi" is an exaggeration.
| Myth | Reality |
|---|---|
| Hedy Lamarr invented Wi-Fi | She patented a frequency-hopping torpedo guidance system |
| She was the first to come up with frequency hopping | The idea existed earlier (Tesla, 1920 and 1939-1940 patents) |
| The patent was used right away | The Navy didn't use it, and the patent expired in 1959 |
| She was never recognized | 1997 EFF Pioneer Award, 2014 National Inventors Hall of Fame |
Lamarr's worth doesn't need a myth. According to Wikipedia, in 1997 she became the first woman to receive the Invention Convention's BULBIE Gnass Spirit of Achievement Award, and in 1998 she received the Viktor Kaplan Medal of the Austrian Association of Patent Holders and Inventors. In that same year, 1997, she and Antheil were awarded the Electronic Frontier Foundation's Pioneer Award, and in 2014 she was posthumously inducted into the US National Inventors Hall of Fame. A film star sitting down to write a patent during the war years is extraordinary in itself.
Do you think telling an invention's story with "exaggeration" serves the person who made it, or does it overshadow their real contribution?