Cambium Networks PMP 450 Series, Руководство по установке

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Chapter 3: System planning 163
W hen t o inst all connect or ized unit s
Most of radio links can be successfully deployed with the integrated ODU. However, the integrated units
may not be sufficient in some areas, for example:
l
Where the path is heavily obscured by dense woodland on an NLOS link.
l
Where long LOS links are required.
l
Where there are known to be high levels of interference.
In these areas, connectorized ODUs and external antennas should be used.
Choosing ext er nal ant ennas
When selecting external antennas, consider the following factors:
l
The required antenna gain.
l
Ease of mounting and alignment.
l
Use dual-polarization antenna (as the integrated antenna).
Note
Enter the antenna gain and cable loss into the Installation Wizard, if the country
selected has an EIRP limit, the corresponding maximum transmit power will be
calculated automatically by the unit.
Calculat ing RF cab le leng t h ( 5.8 GHz FCC only)
The 5.8 GHz band FCC approval for the product is based on tests with a cable loss between the ODU and
antenna of not less than 1.2 dB. If cable loss is below 1.2 dB with a 1.3 m (4 ft) diameter external antenna,
the connectorized 450 Platform Family may exceed the maximum radiated spurious emissions allowed
under FCC 5.8 GHz rules.
Cable loss depends mainly upon cable type and length. To meet or exceed the minimum loss of 1.2 dB, use
cables of the type and length specified in RF cable lengths required to achieve 1.2 dB loss at 5.8 GHz
(source: Times Microwave). This data excludes connector losses.
Table 110 :RF cable lengths required to achieve 1.2 dB loss at 5.8 GHz
RF cable type Minimum cable length
LMR100 0.6 m (1.9 ft)
LMR200 1.4 m (4.6 ft)
LMR300 2.2 m (7.3 ft)
LMR400 3.4 m (11.1 ft)
LMR600 5.0 m (16.5 ft)
Note
If an IP address that is set in the module is not the 169.254.x.x network address,