GE MDS Mercury Series, Справочное руководство

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152 Mercury Reference Manual 05-4446A01, Rev. C
Antennas
The radio equipment can be installed with a number of antennas. The
exact style used depends on the physical size and layout of a system.
Contact your factory representative for specific recommendations on
antenna types and hardware sources.
In general, an omnidirectional antenna ( Figure 5-4 ) is used at the Access
Points and mobile Remote stations. This provides equal signal coverage
in all directions.
NOTE:
Antenna polarization is important. If the wrong polarization is
used, a signal reduction of 20 dB or more will result. Most
systems using a gain-type omnidirectional antenna at Access
Point stations employ vertical polarization of the signal; there-
fore, the Remote antenna(s) must also be vertically polarized
(elements oriented perpendicular to the horizon).
When required, horizontally polarized omnidirectional
antennas are also available. Contact your factory representa-
tive for details.
Invisible place holder
Figure 5-4. Typical Omnidirectional Antennas
At fixed Remote sites, a directional Yagi antenna ( Figure 5-5 on
Page 153 ) minimizes interference to and from other users. Antennas are
available from a number of manufacturers.
High-gain Type
Unity-gain Type