the object to be protected. This field is tuned by a balance between the
electricity capacitance and the electrical inductance. The body capacitance
of an intruder who enters the field unbalances the electrostatic energy of
the field. This unbalance activates the alarm system.
a. Advantages. This system provides an invisible protective field.
affords a high grade of protection and it is simple to install.
b. Disadvantages. This system can only be applied to metal ungrounded
objects; housekeeping of protected area or object must be carefully watched.
13. Weight Director.
This is a sensor(s) used to detect the increase of
weight, such as a weight mat. It is also used to detect some decrease of
weight, such as a scale. This system can be so sophisticated that it can
detect weights to .001 of a gram.
Simple to install, this system is also difficult to
defeat. It is easy to hide or camouflage and is salvageable.
The system must be periodically replaced.
cleaning crews are in the area, the system must be deactivated.
Closed Circuit Television (CCTV).
a. CCTV is not a true intrusion detection sensor in itself, but it is
very useful in physical security operations.
Also, it is often used to
complement an alarm system. This may be done by placing cameras at critical
locations. Doing so will provide direct visual monitoring from a -vantage
point. Closed circuit television may be used on gates that are not manned
all the time by guards. The system may be used for surveillance of security
cages and high value goods in warehouses. Fence lines, movement of cargo,
and parking lots may also be watched using this system.
b. CCTV should be enclosed in metal housings which are lockable. This
will prevent unauthorized tampering. All cables should be inserted in metal
conduit when at all possible.
c. Normal use of TV on gates includes the use of a two-way
communication system and an electrically run gate lock.
covered between the monitor panel and the gate. With this device, the guard
at the monitor panel can be alerted on the speaker by a person wanting to
The guard can determine his authority to enter, and he can then
release the gate lock.
d. A great advantage of CCTV is that it can backup IDS sensors.
is helpful when checking out areas before a response force arrives.
also has videotape recording capability.
e. The greatest problem in CCTV usages is the light intensity required
for cameras. This requirement must be determined and the availability of