Chapter 3: System planning
Link planning
Page 3-24
Link planning
This section describes factors to be taken into account when planning links, such as range,
obstacles path loss and throughput. LINKPlanner is recommended.
LINKPlanner
The Cambium LINKPlanner software and user guide may be downloaded from the support
website (see
).
LINKPlanner imports path profiles and predicts data rates and reliability over the path. It allows
the system designer to try different antenna heights and RF power settings. It outputs an
installation report that defines the parameters to be used for configuration, alignment and
operation. Use the installation report to compare predicted and actual link performance.
Range and obstacles
Calculate the range of the link and identify any obstacles that may affect radio performance.
Perform a survey to identify all the obstructions (such as trees or buildings) in the path and to
assess the risk of interference. This information is necessary in order to achieve an accurate
link feasibility assessment.
The PTP 670 Series is designed to operate in Non-Line-of-Sight (NLoS) and Line-of-Sight (LoS)
environments. An NLOS environment is one in which there is no optical line-of-sight, that is,
there are obstructions between the antennas.
The PTP 670 Series will operate at ranges from 100 m (330 ft) to 250 km (156 miles), within four
ranging modes: 0-40 km (0-25 miles), 0-100 km (0-62 miles), 0-200 km (0-125 miles), and 0-
250 km (0-156 miles). Operation of the system will depend on obstacles in the path between the
units. Operation at 40 km (25 miles) or above will require a near line-of-sight path. Operation at
100 m (330 ft) could be achieved with one unit totally obscured from the other unit, but with the
penalty of transmitting at higher power in a non-optimal direction, thereby increasing
interference in the band.
Note
The maximum range for the HCMP topology is 40 km. The maximum range achieved
for a link in the HCMP topology tends to be lower than in the PTP topology because
the Master ODU is normally installed with a sector or omni-directional antenna.
LoS links in radar regions
When planning an LoS link to operate in a radar detection region, ensure that receiver signal
level is low enough to allow the PTP 670 to detect radar signals:
•
With integrated antennas, the recommended minimum LoS operating range is 110 meters
(360 ft) for 5.2 GHz or 5.4 GHz, and 185 meters (610 ft) for 5.8 GHz. Shorter operating ranges
will lead to excessive receiver signal levels.
