Today in the museum I saw The Thing in person – simply a brilliant espionage device. In 1945, a group of Soviet schoolchildren presented a large wooden Great Seal of the United States to the U.S. Ambassador in Moscow, Averell Harriman, as a “gesture of friendship”. The seal was beautifully hand-carved and hung in the ambassador’s office for a whole 7 years. And it leaked secrets!
No batteries involved! It was all very clever, especially for 1945.
Essentially, it was a passive radio relay or “parasitic resonator”. Inside the wooden seal was a small metal cylinder with a membrane and an antenna-rod.
Soviet operators directed a specific frequency radio wave (about 330 MHz) into the ambassador’s office.
Inside the device was a cavity resonator, tuned to the same frequency. It “responded” to the radio signal and began to retransmit it back.
On one side of the cylinder was a thin flexible membrane. It vibrated from the sound in the room (voices, footsteps).
The vibrations of the membrane altered the capacity and resonance parameters of the device, slightly shifting the reflected radio signal by frequency and phase. This was the modulation of speech onto the external signal.
Outside the building (like in a KGB car nearby), the retransmitted signal was received and the sound modulation was extracted – effectively capturing the overheard conversation.
Why was this almost impossible to detect? The device had no battery and emitted nothing by itself. It “came to life” only when irradiated with an external radio signal. In standard radio monitoring checks, it remained “dead”. Essentially, it was akin to an ancestor of the RFID tag – a passive device that operates only on external request.
But most interestingly, the inventor was Leon Theremin, the same person behind the musical instrument “thereminvox” (played with hands in the air).
His biography reads like a novel. In the early 1920s, Theremin went to the U.S., patented his thereminvox instrument, and collaborated with RCA; his New York studio was visited by Charlie Chaplin, Albert Einstein, Gershwin, and other notable personalities. It is written that he visited the USSR – Already in 1926, he demonstrated television at the Kremlin.
At that time, televisions with screens the size of a matchbox were being created, but his television had a huge screen (1.5 x 1.5 m) and a resolution of 100 lines. In 1927, the scientist demonstrated his installation to Soviet military leaders K.E. Voroshilov, I.V. Tukhachevsky, and S.M. Budyonny:
state minds watched in horror as Stalin walked through the Kremlin courtyard on the screen.
This sight so frightened them that the invention was immediately classified and quietly buried in the archives, and television was soon invented by the Americans.
Eventually, in 1938, he secretly returned to the USSR, but was soon arrested as a “non-returnee” and sent to the camps, but his talent was still used in the so-called “sharashka” – on projects together with Sergei Korolev, including the development of radio-controlled apparatuses and listening systems, including the aforementioned “Great Seal bug”.
Hi, I'm Rauf Aliev. 