Radwin 2000+ SERIES, Руководство пользователя

Страница: 22 / 276

RADWIN 2000+ Series User Manual Release 4.2.40 3 ‐ 3
Stage 2: Physical Survey
3. On the urban map, check for developed areas situated between the two installation
sites. Pay attention to these areas when performing the physical site survey; there
may be tall buildings, RF towers, or transmitters, which could cause interference to
the link.
4. Check the area between the two sites for obstructions such as:
• High ground ‐ hills or mountains
• Lakes or large bodies of water. Water has a reflection effect on RF signals like a building.
This type of reflection causes the received amplitude to be reduced. As a rule of thumb,
the presence of a large body of water between the link sites may double the required
antenna height.
5. Determine and record the compass bearings between both radio units, relative to
north.
6. If there are obstructions between the two sites, calculate the Fresnel Zone (see Link
Budget Calculator for details).
7. If the site chosen does not meet requirements, consider alternative sites.
8. Use the Link Budget Calculator (on the CD supplied with the equipment or using the
RADWIN Manager) to determine the expected performance.
3.5 Stage 2: Physical Survey
During this stage, you review the environment of the proposed installation location, to ensure
that the link sites are suitable for the wireless network. The results of the physical site survey
should be recorded.

To perform a physical survey:
1. From the compass readings taken in the preliminary survey, find the azimuth (hori ‐
zontal position) that the first ODU should face towards the second ODU.
2. Using binoculars, locate any obstructions such as tall trees, high buildings, hills or
mountains. Look for other RF towers between the two sites. Mark the locations of
the obstructions on the map.
3. Determine the location for the ODU (having regard for existing rooftop installations
and tower space). It should be above any obstructions, considering the Fresnel zone
(see Link Budget Calculator ).
4. If you need to install the radio’s antenna on a tower, make sure that the tower is far
away from overhead electric power lines.
When we mention “ODU”, we mean an outdoor radio unit, or its antenna. If you
are working with the RADWIN 2000i, which is an indoor unit and requires an
external antenna, replace the term “ODU” with “the radio unit’s antenna”.