Central Intelligence Agency
The Central Intelligence Agency (CIA), is an independent civilian foreign intelligence service of the United States federal government. The agency is
tasked with gathering, processing and analyzing national security
information around the world, mainly through human intelligence (HUMINT) .
The CIA was established on 31 December 1948 as the
Office of Scientific Intelligence (OSI), by merging the
Scientific Branch of the Office of Reports and Estimates,
and the Nuclear Energy Group of the Office of Special Operations (OSO).
It is also the successor to the Central Intelligence Group (CIG) and,
to some extent, the World War II Office of Strategic Services (OSS).
Although most of the information is gathered overseas, the CIA also collects
some of its data domestically.
The CIA is the only US agency which is authorized by law to carry out
overseas covert actions on behalf of the President of the United States.
Unlike the Federal Bureau of Investigation (FBI),
the CIA is not a law enforcement agency and has therefore no jurisdiction.
CIA equipment on this website
As a foreign intelligence agency, the CIA has always made heavy use of
so-called covert listening devices,
commonly known as bugs.
In the early days of the electronic espionage tradecraft, such listening devices
were small microphones
that were connected to a listening post
through fixed wires, which is why such a bug is also known as a wire
(even though today many are wireless).
In the periode following WWII, when effectively the
Cold War had begun,
wireless radio bugs were introduced, that were built with a mixture of
miniature valves (tubes) and early transistors. Good example of such bugs
are the SRT-1, SRT-3 and the SRT-5.
The general CIA expression for these devices was Surveillance Radio
Transmitter or SRT.
In most cases these wireless radio bugs were developed by the CIA, or by a third
party on behalf of the CIA. They were neither small nor very sophisticated,
and could easily be detected by someone who was scanning the frequency bands.
In 1952 a mysterious type of listening device was discovered in the study of
the US Ambassador in Moscow. The device had apparently been planted there by
the Soviets in 1945, and was based on a hitherto unknown technology,
which is why the Americans nicknamed it
In a reaction to
this, the CIA initiated a secret research project under the name
which was eventually carried out by the
Dutch Radar Laboratory (NRP)
in Noordwijk (Netherlands).
This research resulted in the development of a series of bugs that did not
need a local power source (such as batteries), but were driven by a very
strong radio signal, the so-called activation beam, from a nearby listening
post (LP). Such bugs were known as Passive Elements or PE,
but they were also identified with the project name Easy Chair
or EC. An example is the EC Mark I.
By the mid-1960s, the technology behind the PE devices was outdated,
as both parties (East and West) had meanwhile developed suitable countermeasures
against them. Furthermore, they had both been complaining about their offices
and embassies being 'bombarded' by the other party, with strong microwave
signals that could potentially cause 'health issues' to their personnel.
From that moment on, a new generation of bugs were developed for
the CIA, mainly by external contractors, such as the
NRP who had previously
made the Easy Chair equipment.
These new SRT bugs were identified by 3-digit numbers,
and introduced audio-masking techniques that made detection of these
devices extremely difficult.
Examples of such audio-masking techniques are
subcarrier modulation, hum-injection and
noise controlled pulse position modulation.
The image on the right shows an
SRT-107 with its antenna,
which uses the latter audio-masking technique.
Devices like the SRT-107
were not particularly small by today's standards, but were really
state-of-the-art when they were first introduced.
They could be fitted in a pre-drilled 1 1/8" hole
and were commonly embedded in a building or inside furniture.
It was the CIA's intention to regularly introduce new audio-masking
and modulation techniques, to defeat the Soviet countermeasures.
The following receivers were developed by or for the Technical Services
Division (TSD) of the CIA:
SRT-1First generation radio bugs (peanut tubes and transistors)
SRT-2Rarely used version
SRT-3All transistor 5 mW bug at the size of a pack of cigarettes
- 1500 MHz bug with audio masking
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