User Manual

4 Characteristics and Specifications
22 SNB900 Radio Modem User Guide
4.1 Introduction
This chapter summarizes the general characteristics and specifications
of the SNB900.
4.2 Antenna Gain
The antennas supplied with an SNB900 do not increase the energy
radiated by the radio modem. They concentrate the energy from the
radio modem in a particular direction. The degree to which they
concentrate radio frequency energy in any particular direction is called
directivity and is measured in decibels (dB). The greater the antenna
gain in dB, the higher the directivity and the more the radiated energy
from the antenna is concentrated in some direction.
42.1 Omni-directional antennas
An antenna that radiates energy equally in all directions (that is, at
every azimuth) in the horizontal plane is called omni-directional. An
omni-directional antenna is not omni-directional in the vertical plane,
and must be oriented vertically.