User's Manual
16
u n w i r i n g o u r w o r l d ™
• Physical environment - Clear, open areas provide better radio range than
enclosed, crowded areas. Physical obstructions such as buildings, trees, or hills
can hinder performance of wireless devices. Avoid locating the TOTAL unit
where there is an obstruction between the sending and receiving antennas.
1. Link Distance
If there is no obstacle in the signal path, the maximum link distance depends primarily on the
type of antenna and the free space path loss. Ensure that your proposed mounting site is
within range of the remote antenna. To help estimate the range, the TOTAL unit has a built-in
Link Budget Calculator under Tools in the Web GUI which is accessible upon logging into
the unit. Please refer to the product User Guide for more information on this tool.
2. Signal Path Clearance (Fresnel Zone)
A radio beam travels from one antenna to another in a straight line. Therefore, the path
between the antennas must be free of major obstacles. The effects of obstacles and terrain,
both along and near the path, have a signicant bearing on the propagation of radio signals
and can cause both interference and signal cancellation.
When choosing a site, consider the effects of the following common obstacles:
• Trees and large plants - A tree directly in the signal path can completely block the
signal. You can avoid this by leaving sufcient clearance above the treetops.
You may need to leave extra clearance above smaller tress to allow for future
growth into the signal path.
• Man-made obstacles - A large round building such as a gas storage
reservoir or water tower that is partially in the path may cause some blocking.
These obstacles may also reect RF, which can lead to multi path interference
with other receivers. Objects in or near the path that have rectangular surfaces
can block and diffract signals over and around them.
• Earth surface - The earth’s curvature may also interfere with the signal if the
antenna is mounted too low. Mount the antenna just high enough to allow
adequate clearance from the ground.
Note:
For tower installations, you may need to climb the tower to verify a
clear signal path to the other antenna.
Chapter 4 - Mounting