The Thing ( Listening Device )
The Thing, also known as the Great Seal bug, was one of the first covert listening devices (or “bugs”) to use passive techniques to transmit an audio signal. It was concealed inside a gift given by the Soviets to the US Ambassador to Moscow. Because it was passive, being energized and activated by electromagnetic energy from an outside source, it is considered a predecessor of RFID technology.
The plaque was presented On August 4, 1945 by a delegation of the Young Pioneer Organization of the Soviet Union, a youth organization for Soviet youth aged 10 to 15. It was presented in friendship as a peaceful gesture towards the Soviet’s World War II ally. Unbeknownst to the ambassador, the plaque contained a listening device that was hidden in holes drilled under the beak of the eagle in the plaque.
The device was extremely thin and powered remotely by an electromagnet energy source making it very difficult to detect. It was designed by Leon Theremin, a famed Russian inventor.
The microphone hidden inside was passive and was only activated when the Soviets decided to turn it on. They usually did so from a van parked outside of the ambassador’s house in which they ultra-high frequency beams at the house. Activated, the microphone would transmit any conversations coming from within range of the bug. When they turned the beams off, the bug was virtually undetectable.
The existence of the bug was originally found by accident. Discovered by a British radio operator had overheard American conversations on an open radio channel and the Americans were alerted. Two additional State Department employees, John W. Ford and Joseph Bezjian, were sent to Moscow in March 1951 to investigate this and other suspected bugs in the British and Canadian embassy buildings.
They conducted a technical surveillance counter-measures”sweep” of the Ambassador’s office, using a signal generator and a receiver in a setup that generates audio feedback (“howl”) if the sound from the room is transmitted on a given frequency.
During this sweep, Bezjian found the device in the Great Seal carving with an untuned video receiver . As the Soviets were beaming radio waves at the ambassador’s office. An American State Department employee was then able to reproduce the results using an untuned wideband receiver with a simple diode detector/demodulator, similar to some field strength meters.
It was hung in the Ambassadors’ residential study (in Spaso House) and remained there until 1952. At that point, George Kennan was the ambassador.
The Central Intelligence Agency set about to analyze the device, and hired people from the British Marconi Company to help with the analysis. Marconi technician Peter Wright, a British scientist and later MI5 counterintelligence officer, ran the investigation.He was able to get The Thing working reliably with an illuminating frequency of 800 MHz. The generator which had discovered the device was tuned to 1800 MHz.
Ambassador Kennan later revealed in his memoirs that the Spasso House had been redecorated under Soviet supervision without and American presence. Surveillance sweeps were done routinely but revealed nothing. He also said that technicians conducting the surveillance asked him to pretend to be working out of the house one evening instead of his office. He therefore summoned his secretary to the Spasso House and began dictating a fictitious letter. At one point, one of the technicians encouraged him to continue with the dictation and began sweeping the room quietly. Eventually his sweep led to the Great Seal plaque which e took apart and found the bug.
The Soviets were undeterred and continued planting bugs throughout the rest of the Cold War.
Creation
Operating principles
The Thing consisted of a tiny capacitive membrane connected to a small quarter-wavelength antenna; it had no power supply or active electronic components. The device, a passive cavity resonator, became active only when a radio signal of the correct frequency was sent to the device from an external transmitter. This is currently referred in NSA parlance as “illuminating” a passive device. Sound waves (from voices inside the ambassador’s office) passed through the thin wood case, striking the membrane and causing it to vibrate. The movement of the membrane varied the capacitance “seen” by the antenna, which in turn modulated the radio waves that struck and were re-transmitted by the Thing. A receiver demodulated the signal so that sound picked up by the microphone could be heard, just as an ordinary radio receiver demodulates radio signals and outputs sound.
Theremin’s design made the listening device very difficult to detect, because it was very small, had no power supply or active electronic components, and did not radiate any signal unless it was actively being irradiated remotely. However, these same design features, along with the overall simplicity of the device, made it very reliable and gave it a potentially unlimited operational life. The antenna was capacitively coupled to the post via its disc-shaped end. The total weight of the unit, including the antenna, was 1.1 ounces (31 grams).The length of the antenna and the dimensions of the cavity were engineered in order to make the re-broadcast signal a higher harmonic of the illuminating frequency. Other sources say the wood behind the beak was undrilled but thin enough to pass the sound, or that the hollowed space acted like a soundboard to concentrate the sound from the room onto the microphone.
Aftermath
Wright’s examination led to development of a similar British system codenamed SATYR, used throughout the 1950s by the British, Americans, Canadians and Australians.
There were later models of the device, some with more complex internal structure (the center post under the membrane attached to a helix, probably to increase Q), and some American models with dipole antennas. Maximizing the Q-factor was one of the engineering priorities, as this allowed higher selectivity to the illuminating signal frequency, and therefore higher operating distance and also higher acoustic sensitivity.
In May 1960, The Thing was mentioned on the fourth day of meetings in the United Nations Security Council, convened by the Soviet Union over the 1960 U-2 incident where a U.S. spy plane had entered their territory and been shot down. The U.S. ambassador Henry Cabot Lodge Jr. showed off the bugging device in the Great Seal to illustrate that spying incidents between the two nations were mutual and to allege that Nikita Khrushchev had magnified this particular incident out of all proportion as a pretext to abort the 1960 Paris Summit.
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