TM
3-6665-316-12
2-6.
OPERATING
PROCEDURES
(continued)
2.
Are the receiver/detectors and transmitter deployed
so that a signal
from the transmitter will cause the detectors to go
into alarm?
A transmitter must be located in a position that will assure communication with all
receiver/detectors with which it is to operate.
To ensure efficient transmission
and reception, the following factors should be considered:
o
Hills and mountains between transmitter and receivers normally limit the
range of the Simulator.
In mountainous or hilly terrain, positions rela-
Locations at the base of a
tively high on the slopes should be selected.
A location that
cliff or in a deep ravine or valley should be avoided.
will give line-of-sight transmission should be selected whenever possible.
o
Dry ground has high resistance and limits th
e
range of good transmission
If possible, the transmitter
and receivers should be
and reception.
located near moist ground, which has much
less resistance. Water, and in
particular salt water, will greatly increase
the distances that can be
covered.
o
Trees
with heavy foliage absorb radio waves, and leafy trees have more of
an ad
verse effect than evergreens.
Wet foliage has more of adverse effect
The transmitter and receiver antennas should be kept
than
dry foliage.
clear
of all foliage and dense brush.
o
A position in
a tunnel or beneath an underpass or steel bridge should not
Transmission and reception under these conditions are almost
be selected.
impossible.
o
Buildings located between the transmitter
and receiver, particularly steel
and reinforced concrete structures, hinder
both transmission and recep-
tion.
o
All types of pole wire lines, such as telephone, telegraph, and high-
tension power lines, should be avoided when you are selecting a site.
Such wire lines absorb power from radiating antennas located in their
vicinity.
Such lines also introduce hum and noise interference in receiv-
ing antennas.
o
Positions adjacent to heavily traveled roads and highways should be
In addition to the noise and confusion caused by tanks and
avoided.
trucks, ignition systems in vehicles may cause electrical interference.
o
Battery-charging units and
should
not
be
located
close
to
transmitter or receivers.
o
Atmospheric conditions can also affect
transmission and
reception.
Such
conditions include fog, thunderstorms,
and sunspots.
2-16
