Site Selection - GE MDS 4790 Series Installation & Operation Manual

MDS 05-3438A01, Rev. F
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Site Selection

For a successful installation, carefully select the site for the master sta-
tion and the remote radios. Suitable sites offer:
• An antenna location that provides an unobstructed path to all the
remote radios in the system
• A source of adequate and stable primary power
• Suitable entrances for antenna, interface, or other required
cabling.
You can quickly determine these requirements in most cases. A possible
exception is the first item—verifying that an unobstructed transmission
path exists. UHF radio signals travel primarily by line-of-sight, and
obstructions between the sending and receiving stations affect system
performance.
If you are not familiar with the effects of terrain and other obstructions
on radio transmission, the following discussion provides helpful back-
ground.
Terrain and Signal Strength
A line-of-sight path between stations is highly desirable and provides
the most reliable communications link in all cases. You can often
achieve a line-of-sight path by mounting each station antenna on a tower
or other elevated structure that raises it high enough to clear surrounding
terrain and other obstructions.
The requirement for a clear transmission path depends on the distance
covered by the system. If the system covers only a limited distance, say
3.1 miles (5 km), then some obstructions in the transmission path might
be acceptable. For longer range systems, any obstruction might compro-
mise the performance of the system, or block transmission entirely.
The signal strength at the receiver must exceed the sensitivity limit by
an amount known as the fade margin to provide reliable operation under
various conditions.
Section 10.2, RF Propagation Planning, beginning on Page 99
a detailed discussion of path planning. Review this section before begin-
ning an installation. Computer software is also available for this purpose
that greatly simplifies the steps involved in planning a path.
On-the-Air Test
If you've analyzed the proposed transmission path and feel that it is
acceptable, conduct an on-the-air test of the equipment and path. This
not only verifies the path study results, but allows you to see firsthand
the factors involved at each installation site.
MDS 4790/9790 Series I/O Guide
includes
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