5 Determining location
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SMARTS II
5.2 Factors determining area coverage
Energy sources, either purposeful emitters such as antennas, or
unintentional emitters such as waveguide leaks, can be omnidirectional
or focused in one direction. Field strength (power density expressed in
mW/cm2 or W/m2) drops off rapidly with distance from the source. In the
far field, field strength follows the inverse square law, i.e., at twice the
distance there is one quarter the field strength. Similarly, at ten times the
distance, the field strength is only one percent as strong. Factors
influencing area coverage include (amongst others):
Position of the SMARTS II
Location of the energy source
Location of people
Energy level of the source.
Direction of energy being emitted
5.3 Preferred location
The
ideal location
for a SMARTS II is
between the source of energy and
people
. The SMARTS II should be "pointed" at the energy source. Under
these conditions, the sensitivity of the monitor is never an issue because
it will always detect a higher field level than the people are exposed to.
Since the SMARTS II activates its alarms at levels below the Standard,
the monitor will always activate its alarm whenever people are in a field
that exceeds the Standard. Under these conditions, there is no limit to
the area that is "covered".
!
Every other location scenario involves a great deal more
thought and some risk that people can be exposed to field
levels above the Standard while the SMARTS II is in fields
below its alarm threshold.
5.4 Alternate locations
Mounting the SMARTS II closer than people will be to the energy
source, but not between the two
. A test bench is a common
example of this situation. The worker sits or stands in front of a test
bench that contains a piece of equipment, like an amplifier, that is
being tested. The SMARTS II is typically hung from the ceiling just
above the transmitter. In this application, the monitor normally
detects an unexpected "leak". Such a leak can occur when there is a
missing, or poor, connection.
Mounting a SMARTS II in a small room with conductive walls
.
Transportable military shelters and the remote broadcast trucks used
in television radio operations for Electronic New Gathering (ENG
trucks) have similar attributes. Both are relatively small "rooms" with
conductive walls, ceilings, and floors. An energy leak can be
detected in two ways
– directly and/or via reflection off the wall or
ceiling.
