User Manual

VoiceXtender Modem Installer’s Guide
System Planning
Rev. A - 8/97 2-3
Directional Antenna
A directional antenna focuses the RF energy in a specific direction. When using
a directional antenna, it should be properly directed toward the opposite end of
the link.
NOTE In many countries, interference from cellular phones and pagers can be present in many
environments. Because these interfering signals exist in a vertical plane, an efficient
method to reduce their effect is to position the directional antenna in a horizontal plane
(horizontal polarization). The interference rejection will be 15 - 20 dB.
Figure 2-2
Yagi Directional Antenna
NOTE Antennas are described in the accessory list available from your distributor, and can be
purchased from Cylink or a Cylink distributor.
Path Analysis
Path analysis examines the direction and length of a desired line-of-sight
path, the equipment being considered, antenna gain, cable loss, and the
environmental context (terrain and climate). It also determines the projected
path loss. In situations where a clear line-of-sight path of less than five miles
exists, path analysis might not be necessary. Otherwise, it is recommended
that a path analysis be performed.