Hedy Lamarr and George Antheil's Frequency Hopping Secret Communication System
A 1942 patent for a radio-controlled torpedo guidance system that used synchronized player piano rolls to hop between frequencies, preventing enemies from jamming the signal.
Original patent title: “Secret communication system”
A 1942 patent for a radio-controlled torpedo guidance system that used synchronized player piano rolls to hop between frequencies, preventing enemies from jamming the signal. Granted to Individual in 1942 with 82 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
The system uses two synchronized mechanisms, similar to those found in player pianos, to change the carrier frequency of a radio transmitter and receiver simultaneously. By rapidly switching frequencies in a predetermined sequence, the signal becomes extremely difficult for an adversary to detect or jam. The patent describes using perforated paper rolls to control the timing of these frequency shifts, ensuring both the sender and receiver stay perfectly aligned.
The gap
What does this patent NOT cover?
- Does not cover digital frequency hopping methods using modern microprocessors.
- Does not cover encryption or scrambling of the actual message content.
- Does not cover non-mechanical methods of frequency synchronization.
- Does not cover the use of radio waves for anything other than remote control of a torpedo.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The inventors realized that if you can't stop an enemy from jamming a single frequency, you should simply move the conversation to a new channel before they can react, using a shared 'rhythm' to stay in sync.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Modern Wi-Fi routers
Bluetooth device pairing
Military secure radio communications
GPS signal transmission
Why it matters
The bigger picture
This invention laid the conceptual foundation for modern spread-spectrum communication. It is the core technology behind Wi-Fi, Bluetooth, and GPS, proving that frequency hopping could make wireless signals resilient against interference.
Filed
June 10, 1941
Granted
August 11, 1942
Market context
Who's building on this
Companies in this space
Major telecommunications companies like Qualcomm and Ericsson have built their entire business models on the evolution of spread-spectrum technology. The concepts pioneered here are now standard in every mobile network operator's infrastructure.
Market impact
While the patent was largely ignored by the military during the war, it became essential decades later as the radio spectrum became crowded. It enabled the development of robust wireless networks that can operate in high-interference environments, effectively creating the modern connected world.
Claim 1 — Plain English
What this patent covers
The system uses two synchronized mechanisms, similar to those found in player pianos, to change the carrier frequency of a radio transmitter and receiver simultaneously. By rapidly switching frequencies in a predetermined sequence, the signal becomes extremely difficult for an adversary to detect or jam. The patent describes using perforated paper rolls to control the timing of these frequency shifts, ensuring both the sender and receiver stay perfectly aligned.
The clever bit
The inventors realized that if you can't stop an enemy from jamming a single frequency, you should simply move the conversation to a new channel before they can react, using a shared 'rhythm' to stay in sync.
What it does not cover
- Does not cover digital frequency hopping methods using modern microprocessors.
- Does not cover encryption or scrambling of the actual message content.
- Does not cover non-mechanical methods of frequency synchronization.
- Does not cover the use of radio waves for anything other than remote control of a torpedo.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Early stage
Citation count
38/40
Highly cited
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$25K – $81K
Midpoint $50K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
Concepts involved
Citations
Patent lineage
Cite this patent
George, A., & Kiesler, M. H. (1942). Hedy Lamarr and George Antheil's Frequency Hopping Secret Communication System (U.S. Patent No. 2,292,387). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2292387/hedy-lamarr-frequency-hopping
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does Hedy Lamarr and George Antheil's Frequency Hopping Secret Communication System cover?
A 1942 patent for a radio-controlled torpedo guidance system that used synchronized player piano rolls to hop between frequencies, preventing enemies from jamming the signal.
Who owns patent US 2292387?
Individual owns this patent, granted in 1942.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 2292387 cited by?
This patent has been cited by 82 later patents that build on its ideas.
What problem does this patent solve?
This invention laid the conceptual foundation for modern spread-spectrum communication. It is the core technology behind Wi-Fi, Bluetooth, and GPS, proving that frequency hopping could make wireless signals resilient against interference.
What does this patent NOT cover?
Does not cover digital frequency hopping methods using modern microprocessors.
Same assignee
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