Hedy Lamarr & George Antheil Patent Frequency-Hopping "Secret Communication System"
US Patent 2,292,387, filed on 10 June 1941 and granted on 11 August 1942, described a radio guidance link for torpedoes that hopped between carrier frequencies in step at transmitter and receiver to resist jamming. The US Navy did not adopt it during the war.
02Deep-Dive Technical Analysis
The patent paired synchronised perforated records, like player-piano rolls, at the transmitting station and in the torpedo. They retuned both ends in lockstep, so the control signal never sat on one frequency long enough to be found or jammed. The patent notes a standard 88-row piano record would allow 88 carrier frequencies. Security rests on a shared secret hopping sequence: a precursor of FHSS. The Patent Office and historians note frequency hopping had earlier proposals, so Lamarr–Antheil were not its sole originators.
03Vulnerability & Exploit Flow
Defensive milestone: counters narrowband jamming and interception of a fixed-frequency radio control channel.
04Recommended Defense & Mitigation Protocol
Pseudo-random carrier hopping driven by a pre-shared synchronised sequence at both ends.
05Security Impact & Geopolitical Consequence
The patent became an emblem of spread-spectrum anti-jamming. Electronic frequency hopping (e.g. Sylvania, late 1950s) reached US Navy ships during the 1962 Cuban blockade. How much this patent directly influenced later military and civil spread spectrum (Bluetooth, GSM slow hopping) is disputed.
06Authoritative Standards & External References
07Related Topic Cluster Records
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