SATELLINE-3AS
User Guide, Version 2.3
90
10.3 Antenna installation
10.3.1 Hand-held
equipment
·
¼-wave antenna (wavelength at frequency of 450 MHz is approximately 70 cm)
·
Helix-antenna
Antennas are installed directly to the TNC-type antenna connector at the upper part of the radio
modem.
10.3.2 Mobile
equipment
·
¼-wave antenna
·
½-wave antenna
The ideal installation position is vertical, and there should be at least 0.5 m of free space
around the antenna. In small systems a ¼-wave antenna is sufficient. A separate ground plane
should be placed under the antenna (vehicle rooftop or the engine hood or trunk door are
usually suitable). In problematic cases the most suitable type is a ½-wave antenna. It can be
installed directly at the top of a pipe with the added benefit of gaining as much as free space
around the antenna as possible. In cases which the antenna cannot be directly connected to the
TNC-connector of the radio modem, a coaxial cable with 50
W
impedance must be used
between the antenna and the TNC-connector.
10.3.3 Base
stations
·
Omni-directional antennas ( ¼- , ½- or 5/8-wave antenna)
·
directional antennas (yagi/multi-element antenna or corner antenna)
The antenna should be installed in a vertical position. The exact location of the antenna
depends on several factors, such as the size of the overall system and the coverage area terrain
contours. A rule of thumb is that the base station antenna should be located at the highest point
of the coverage area and as close to the center of the coverage area as possible. The base
station antenna can also be located inside a building, if the walls of the building do not contain
metal.
NOTE!
Because of the great transmission power of SATELLINE-3AS Epic radio modem, only an
external antenna is allowed. A whip-antenna directly connected to the antenna connector
must not be used
.