18 |
P a g e
Signal Strength vs Received Power
100
90
80
70
60
50
40
30
20
10
0
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
Power [dBm]
Figure A.2
–
Received Power Chart
Maximizing Range
Under favorable conditions the ZW-ED can achieve a, line of sight, wireless link
distance of up to 1000m. Generally, most indoor applications will not be able to achieve
these distances, although steps can be taken to maximize range. Ensure the Receiver
and End Device are located away from large obstacles and other RF sou rces such as
Wireless Access points and microwaves. Keep objects clear of the zone between the
End Device and Receiver. Metal objects, walls, and cubical partitions will all significantly
reduce the signal strength.
The antenna provided with the ZW-ED is a dipole. Care must be taken in the
positioning of the antenna to achieve the best possible range. The gain of the antenna
is lower along the axis of the antenna. Do not point the ZW-ED antenna in the direction
of the Receiver. When possible, the ZW-ED antenna should be parallel to the Receiver
antenna.
Keep the antenna away from dense or metallic structures. Metallic structures should
be kept away by at least 0.8" (2 cm), although 2.4" (6 cm) is recommended. Objects too
close to the antenna may screen the ZW-ED from the Receiver. Reflections off nearby
objects can also cause destructive interference reducing received signal strength.
For long distance connections the ZW-ED and the Receiver should be elevated to
keep the signal from being attenuated by the ground. Elevate each device by at least
0.6 meters above the ground for each 100 meters or separation. It is best to keep this
same clearance distance to walls, ceilings and other obstructions as well.
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