User Manual

Low Gain Omni Antennas High Gain Omni Antennas
Node A
Node C
Node B
Signal A
Signal B
Signal C
Gateway’s
Signal
6 miles
6dB Gain
Low-Gain
Low-gain omni-directional antennas work well in multipath
industrial environments, such as inside metal buildings.
High-gain antennas work well in line-of-sight conditions.
Using an omni-directional antenna in the center of a star
topology ensures all radio devices receive a signal.
A high gain omni antenna with increased gain also has a
circular radiation pattern when viewed from the top. From
the side view, however, the decreased energy sent
vertically increases the energy transmitted horizontally. The
radiation pattern stretches to extend the range, focusing
the signal along a horizontal plane. This makes higher gain
omni antennas more sensitive to changes in elevation
between the Gateway and its Nodes.
Increasing the gain of omni-directional antennas results in
less energy sent vertically and more energy sent
horizontally, extending the range.
Directional (Yagi) Antennas
A directional, or Yagi, antenna focuses the radio signal in one specific direction.
Node A
Node B
Gateway’s
Signal
If you compare antenna radiation patterns to light, an
omni antenna radiates a radio signal like a light bulb
— evenly in a spherical pattern. A directional antenna
radiates similar to a flashlight — focusing the signal
only in one direction. The higher the gain, the more
focused the beam becomes.
Yagi antennas are best used in line-of-sight radio
systems because Yagis focus the radio signal in a
specific direction. In the following example, the
Gateway uses an omni antenna to receive radio
signals from multiple directions but the Nodes use
Yagi antennas aimed directly at the Gateway to send
and receive the radio signal.
Antenna Basics
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