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2.6.2 OMNI-DIRECTIONAL ANTENNA
In general, an omnidirectional antenna should be used at a master station and Relay Points. This allows equal coverage
to all of the remote locations. Omni directional antennas are designed to radiate the RF signal in a 360- degree pattern
around the antenna. Short range antennas such as folded dipoles and ground independent whips are used to radiate
the signal in a ball shaped pattern while high gain omni antennas, such as a collinear antenna, compress the RF
radiation sphere into the horizontal plane to provide a relatively flat disc shaped pattern that travels further because
more of the energy is radiated in the horizontal plane.
2.6.3 YAGI ANTENNA
At remote locations (not used as a Relay Point), a directional Yagi is generally recommended to minimize interference
to and from other users.
2.6.4 VERTICAL DIPOLES
Vertical dipoles are very often mounted in pairs, or sometimes in groups of three to four, to achieve even coverage and
to increase gain. The vertical collinear antenna usually consists of several elements stacked one above the other to
achieve similar results.
Table 11 Antenna Types
Omni (Vertical Collinear)
Yagi
Vertical Dipole
2.6.5 FEEDLINE
The choice of feedline should be carefully considered. Poor quality coaxial cables should be avoided, as they will
degrade system performance for both transmission and reception. The cable should be kept as short as possible to
minimize signal loss. See the following table for a list of feedline recommendations.
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Guardian™ Serial Modem or Analog Radio for Licensed Spectrum PN 001-5006-000 Rev. 3
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