SITE SELECTION CRITERIA
There are various issues that need to be taken into consideration when choosing a location for
the network infrastructure. The following is a list of those considerations. There may be others
as each site is unique.
•
Height is essential when installing a Cyclone backhaul module. The Cyclone AP must be
mounted higher than other objects located immediately around it such as trees, buildings,
tower legs, etc.
•
There should be no obstructions that will interfere with the unit’s antenna. The area
immediately in front of an access point module must be clear of all obstructions.
•
Will the installation area change in the future? Will there be structures high enough to
interfere with the signal? Will trees grow into the line-of-sight path?
•
When possible, avoid high RF energy sites. Do not place Cyclone equipment in the same
plane as other RF equipment.
•
The means used by the installer to attach the backhaul module to the tower, rooftop, or
pole should be rigid and should not move or flex due to wind or other vibrations.
•
Tower availability…will a tower have to erected?
•
There must be grounding systems available for protection of the Cyclone equipment.
•
Lighting arrestors are required in installation areas to transport lightning strikes away
from equipment.
GENERAL CONSIDERATIONS
Fresnel Loss
- The Fresnel Zone is a theoretical area around the line of sight of an antenna
transmission that can affect the signal strength. Objects that penetrate the Fresnel Zone can
cause fading of the transmitted signal. This fading is caused by the cancellation of the signal due
to out-of-phase reflections. An unobstructed line of sight is important, but it is not the only
determination of an adequate placement. Even though the path has a clear line of sight, if
obstructions (such as terrain, vegetation, metal roofs, cars, etc.) penetrate the Fresnel zone,
there will be signal loss.
Free Space Path Loss
– As an RF signal travels through space, it is attenuated by the distance
from the initial transmission point. The farther away from the transmission point, the weaker the
RF signal.
Foliage Loss
– Tree and plant foliage will cause additional signal loss. Seasonal density,
moisture content of the foliage, and other factors such as wind may change the amount of loss.
Caution should be used when a link may transmit though this type of environment.
Carrier to Interference
– describes how much signal advantage must be engineered into the
radio link to tolerate an interfering transmission.
CHANNEL PLANS
900 MHz Recommended Frequencies
The following are the 3 non-overlapping channels that are recommended:
•
906 MHz
•
915 MHz
•
924 MHz
