User`s guide

MDS 05-2806A01, Rev. E.1 MDS iNET 900 Series User’s Guide 133
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Figure 5-4. Typical Omnidirectional Antennas
At Remote Gateway sites and units in point-to-point LANs, a directional
Yagi (Figure 5-5) antenna is generally recommended to minimize inter-
ference to and from other users. Antennas are available from a number
of manufacturers.
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Figure 5-5. Typical Yagi Antenna (mounted to mast)
Feedlines
The choice of feedline used with the antenna should be carefully consid-
ered. 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 trans-
mission, 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
®
.
Table 5-1 lists several types of popular feedlines and indicates the signal
losses (in dB) that result when using various lengths of cable at
High-gain Type
Unity-gain Type