User's Manual

SATELLINE-4Pro
User Guide v0.93 DRAFT
60
11.2 Antenna installation
11.2.1 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 ohm impedance must be used between the antenna and the
TNC-connector.
11.2.2 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 centre 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.
11.2.3 General antenna installation instructions
The reliability and the achievable coverage of useful signal strength can be severely affected by the
positioning of the antenna. Antenna and cable connectors should have gold-plated pins and
sockets, as use of low quality connectors can lead to eventual oxidation of the connector surfaces,
which in turn may degrade the contact and cause additional attenuation. Good quality tools and
materials must be used when installing radio modems, antennas and cables. The weather tolerance
of the materials used must also be taken into account. Installed materials must withstand all
foreseeable weather conditions (frost, excess sun, direct UV-radiation, seawater etc.). Also possible
environmental pollution must be considered (acids, ozone etc.).
NOTE!
Because of the great transmission power of SATELLINE-4Pro radio modem, only an external
antenna is allowed. A whip-antenna directly connected to the antenna connector must not
be used.