Cambium Networks PTP 250, User Manual

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Planning for connectorized units Chapter 2: Planning considerations
2-12 phn-2510_002v000 (Mar 2012)
Planning for connectorized units
This section describes factors to be taken into account when planning to use connectorized
ODUs with external antennas in PTP 250 links.
When to install connectorized units
The majority of radio links can be successfully deployed with the integrated PTP 250.
However the integrated units may not be sufficient in some areas, for example:
x
Where the path is heavily obscured by dense woodland on an NLOS link.
x
Where long LOS links (>23 km or >14 miles) are required.
x
Where there are known to be high levels of interference.
PTP LINKPlanner can be used to identify these areas of marginal performance.
In these areas, connectorized ODUs and external antennas should be used.
Choosing external antennas
When selecting external antennas, consider the following factors:
x
The required antenna gain.
x
Ease of mounting and alignment.
x
Antenna polarization:
o
For a simple installation process, select one dual-polarization antenna (as the
integrated antenna) at each end.
o
To achieve spatial diversity, select two single-polarization antennas at each end.
Spatial diversity provides additional fade margin on very long LOS links where
there is evidence of correlation of the fading characteristics on Vertical and
Horizontal polarizations.
For connectorized units operating in the USA or Canada, choose external antennas from
those listed in
FCC and IC approved antennas on page 2-30 . Do not install any other
antennas. For links in other countries, it is not mandatory to choose antennas from FCC
and IC approved antennas on page 2-30 , but this may be used as a guide.
If an EIRP limit is in force, refer to Calculating maximum power level for connectorized
units on page 2-13 .