Omega Vehicle Security zSeries manual With Line-of-Sight, Distance feet Radius feet

5.2 With Line-of-Sight

When installing your Coordinator it is important to position your device in such a way to optimize the antenna location within what’s known as the “Fresnel Zone”. The Fresnel Zone can be thought of as a football-shaped invisible tunnel between two locations that provides a path for RF signals between your End Device and your Coordinator.

END DEVICE	COORDINATOR
	ANTENNA
ANTENNA	FRESNEL ZONE

Figure 5.2 Fresnel Zone

In order to achieve maximum range, the football-shaped path in which radio waves travel
must be free of obstructions. Obstacles in the path (especially metal) will decrease the
communication range between your End Device and Coordinator. Also, if the antennas
are mounted just barely off the ground or below the ceiling, over half of the Fresnel zone
ends up being obstructed resulting in significant reduction in range. Below is the
calculated radius of the football-shaped tunnel for different distance range:
		Distance (feet)	Radius (feet)
		100	3.2
		200	4.5
It is recommended that		300	5.5	least 60% of space is
	within the tunnel of the above radius, at
free of obstruction.
Since signal reaches destination directly in a line-of-sight situation, it is important to
adjust antenna properly to achieve maximum performance. Antenna for the Coordinator
and End Device should be perpendicular to the plane where Coordinator and End
Device is located.

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