Redline Communications WiMAX Forum Certified RedMAX AN-100U, Руководство по установке, Страница: 12 / 38

Red MAX
™
AN-100U
installation guidelines
Doc #70-00059-01-00
Proprietary Redline Communications © 2006
May 30, 2006
Page 12 of 38
2.1.2 Identify the Best Path
The next step is to conduct a general site survey to determine the location for the
antenna. This involves a survey to identify building and structures that can be used to
mount an antenna. Refer to the specification for the maximum IF cable length.
For maximum performance in an OLOS deployment, it is recommended to mount the
antenna in a location where there is direct line of sight to the receiving wireless
system. If the obstruction in the path is not exceptionally high, it may be possible to
aim both antennas near the top of the obstruction. The antenna should be positioned
to provide maximum clearance within the first Fresnel zone of the direct path (as high
as possible, on either a tall building or tower).
The wireless system also supports installation in non-line-of-sight (NLOS)
conditions. A satisfactory multipath RF signal can often be obtained by directing
each antenna towards a structure in sight of both communicating wireless systems.
Figure 4: Survey - Antenna Mounting Locations
The recommended method for obtaining a satisfactory RF signal is to test a number
of antenna positions and measure the signal-to-noise ratio and received signal
strength (RSSI) for each position.
It is also important to test for RF interference at the intended rooftop or tower
installation site. RF interference can be caused by any wireless system in the area that
is operating in the same frequency band as the wireless. Accurate analysis requires
the use of specialized RF test equipment. The primary purpose of these tests is to
determine what channels are available for use on the wireless system.
2.1.3 Antenna Mounting and IF Cable Routing
When the antenna location has been established, plans should be made for installation
of the antenna mast or alternative mounting equipment. Plans should be made for
routing the IF cable from the outdoor unit to the terminal. In some locations it may
also be possible to install the IF cable on the outside of the building. If the building
must be penetrated to run the IF cable, it is important to verify that building
blueprints and/or drawings are up to date and accurate, and that all permissions are
obtained for the required modifications.