User Manual

SPEEDLAN 9000 Series Installation and Operation User Guide Version 3.03
SPEEDLAN 9101, 9102, 9103 & 9104 Hardware 2-17
Antenna Selection Tip: Use a high-gain omni or sectoral antenna for a base station
(9103), and use a grid or directional antenna for a CPE or point-to-point router
(9102).
To install your SPEEDLAN 9102 or 9103 router with an external antenna, do the
following:
Step 1.Verifying Line-of-Sight
Before installing the antenna and router, make sure a clear line-of-sight exists between
the two points. Line-of-sight can be defined as each antenna clearly seeing the other
antenna, and seeing the remote locations when viewing from the central base location.
Be sure to look at the center of origin of the transmission (i.e., the middle of the
antenna). Repeat this procedure from the remote location. Any disruption of the signal
path due to trees, building, or any other obstructions may cause the link to function
incorrectly. Make sure at least 60 percent of the RF signal is unobstructed by any path
blockages.
Figure 2-11: Line-of-sight (LOS) diagram
Note: For long distances, additional antenna height is often required to overcome
signal diffraction and to provide clear Radio LOS. For Radio LOS, a clear Fresnel
(Freh-nel) zone is required to minimize diffraction effects. The Fresnel zone is shaped
like an elongated football. The most clearance is required at the mid-point between the
two sites.
Visual Line of
Si h
Fresnel Zone
di
Obstruction
Hih
A
bove Mean Sea
Ll)
Earth
Tower
Hih
A
bove
MSL)