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TSCM (Technical Surveillance Counter-Measures) is the
original United States military abbreviation denoting the
process of bug-sweeping or electronic countersurveillance.
It is related to ELINT, SIGINT and Electronic countermeasures
(ECM).
The United States Department of defence defines a TSCM
survey as a service provided by qualified personnel to detect
the presence of technical surveillance devices and hazards
and to identify technical security weaknesses that could
aid in the conduct of a technical penetration of the surveyed
facility. A TSCM survey will provide a professional evaluation
of the facility's technical security posture and normally
will consist of a thorough visual, electronic, and physical
examination in and about the surveyed facility.
The advent of multimedia devices and remote control technologies
allow huge scope for removal of massive amounts of data
in very secure environments by the staff employed within,
with or without their knowledge. Even PlayStation Portables
(PSPs) have wireless connectivity and optional storage capacity.
Therefore connection and forward on receive over 54 Mbit/s
wireless for hundreds of meters is achievable.
Radio Frequencies
Most bugs emit some form of electromagnetic radiation,
usually radio waves. The standard counter-measure for bugs
is therefore to "sweep" for them with a receiver,
looking for the radio emissions. Low-tech sweeping devices
are available through amateur electrical magazines, internet
spy shops but sweeping with these cheap devices is no way
foolproof. Advanced bugs can be remotely operated to switch
on and off, and some even rapidly switch frequencies according
to a predetermined pattern in order to make location with
sweepers more difficult. Only top of the range state-of-the-art
professional sweeping devices will have the ability to detect
modern surveillance devices.
The non-linear junction detector, or an NLJD,
is a device that illuminates a small region of space with
high-frequency, RF energy. Any "non linear junction"
in the vicinity -- for example, and particularly, the p-n
junction -- will receive this energy, and because of the
non-linear nature of the junction, it will rectify it, re-emitting
some of it on multiples of the illumination frequency (2nd
& 3rd harmonic frequency). The detector has two sensitive
receivers tuned for these harmonics, as well as appropriate
processing and displays to make their presence known to
the user of the device.
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