INSTALLATION
FIXED STATIONS
408 ENVOY™ TRANSCEIVER REFERENCE MANUAL
Antenna tuners in a fixed station
The purpose of an antenna tuner is to adjust the wavelength of the antenna according
to the selected frequency. This ensures an optimum load to the transceiver so that it
achieves maximum efficiency. A tuner is usually installed when a single antenna is
operating on a range of frequencies, for example, the long wire and vertical whip
antennas, and when there is limited space available to install additional antennas.
The radiating portion of the antenna connects directly to the tuner through a
high-voltage insulator. The antenna length must be compatible with the tuner
installed, and be suitable for the working frequency range.
CAUTION: It is essential that the correct antenna type, site location, and earthing
technique be chosen so that the system operates effectively.
NOTE: An antenna tuner is not necessary with a broadband antenna system.
Antenna supports in a fixed station
Supports are used to position the antenna to face the desired direction of
communication. The supports suspend the antenna in the air and provide it with
adequate rigidity. The supports must be able to withstand extreme environmental
conditions.
CAUTION: The antenna may not tune or remain tuned if it sways or sags
excessively.
Existing supports can be used, such as trees or windmill towers, if they are suitably
positioned according to the desired direction of communication. Support systems also
include freestanding or guyed masts.
NOTE: If the supports are unstable, additional support, such as guy anchors,
should be provided.
The antenna is tied to various supports by wire or nylon rope guys to ensure the
antenna is insulated from its supports. If wire guys are used, two ceramic insulators
must be provided at each end of the antenna. If metallic supports are used, position the
insulators so that the antenna is at least 2 m (2 yd) from the mast. Ceramic insulators
ensure the signal is not connected directly to the earth via the metallic supports.
Installing the transceiver in a fixed station
On receiving your Envoy™ Transceiver, check the contents against the packing list.
Make sure that all equipment itemised on the packing list is present and that there is
no damage to the equipment before you start installing the system.
If anything is missing or damaged, please contact your nearest Codan office
immediately to obtain the correct warranty service procedures. This ensures prompt
assistance, minimal turnaround time, and avoids any freight issues.
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