Feedlines - GE MDS iNET Series Reference Manual

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 the Access Point
station employ vertical polarization of the signal; therefore, 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 representative for details.
At Remote Gateway sites and units in point-to-point LANs, a directional Yagi (Figure 4-6) antenna is gen-
erally recommended to minimize interference to and from other users. Antennas are available from a
number of manufacturers.
Figure 4-6. Typical Yagi Antenna (mounted to mast)

Feedlines

The choice of feedline used with the antenna 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.
For cable runs of less than 20 feet (6 meters), or for short range transmission, an inexpensive type such as
Type RG-8A/U may be acceptable. Otherwise, we recommend using a low-loss cable type suited for
900 MHz, such as Heliax
110
High-gain Type
Unity-gain Type
Figure 4-5. Typical Omnidirectional Antennas
®
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MDS iNET Series Reference Manual
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05-2806A01, Rev. L