Should neither of these methods be available it will be necessary to bond as many
large metallic objects, such as the engine and propeller shaft, together to form a
ground.
Which ever method is used the ground run from the ground system to the antenna
tuner should be as short as possible and use copper strap at least 50mm
wide.(wider if available). Consideration must always be given to the problem of
electrolysis. Severe structural damage may occur if electrolysis is present.
All connections in marine situations are subject to corrosion and oxidation. To
minimise this all joints should be cleaned and have silicon grease applied before
assembly. Under severe conditions joints should be protected with self vulcanising
rubber tape.
Corrosion
Barrett 550/950 or 530/930 Connection Detail
OPTIONAL 10 or 6 METRE EXTENTION
CABLE WITH CONNECTORS
P/N BCA 90032/40
CABLE & CONNECTORS
SUPPLIED WITH
911 ANTENNA TUNER
HEAVY DUTY FUSE
& HOLDER P/N BCA90018
+13.8V
6 METRE POWER CABLE
SUPPLIED WITH TRANSCEIVER
6 METRE CABLE & CONNECTORS
SUPPLIED WITH 911
ANTENNA TUNER
GND BLACK
OPTIONAL
ACCESSORY
INTERFACE
P/N BCA 90016
STANDARD INTERFACE
SUPPLIED WITH 911
ANTENNA TUNER
6 METRE REMOTE
CONTROL CABLE
WITH 930R/950
ANTENNA
FEEDTHRU INSULATOR P/N BCA91701
EXTENSION SPEAKER
AND MICROPHONE SUPPLIED
STANDARD WITH REMOTE HEAD
911
AUTOMATIC
ANTENNA
TUNER
REMOTE CONTROL HEAD
SUPPLIED STANDARD WITH
930/950 REMOTE CONTROL
(TRUNK MOUNT) TRANSCEIVER
OR AS AN OPTION IF DUAL
CONTROL IS REQUIRED
WITH A 930/950 LOCAL CONTROL
TRANSCEIVER
BASE STATION INSTALLATIONS
Antenna
Transceiver and Tuner Mounting
Ground (Earth) System
Various antenna configurations, such as vertical whips, long-wires and loops, can
be used for base station installations, using the Barrett 911 Automatic Antenna
Tuner.
In general however the following points should be considered:-
1.
The antenna should be mounted as far away as possible from buildings,
trees, vegetation and sources of electrical interference. If metallic masts
or supports are used, arrange insulators to ensure the antenna is spaced
at least 2 metres from the mast.
2.
Remember the radiating part of the antenna starts at the tuner.
The
location of the bottom portion of the antenna is very important.
3.
Horizontal wire antennas have maximum radiation broadside to the
antenna when the frequency is less than 1/4 wavelength. Radiation is at a
minimum at the end points of the antenna.
4.
Inverted "V" installation of horizontal antennas minimises the directivity
and is recommended for omni-directional coverage.
5.
High voltages are present on the antenna system. The antenna tuner and
antenna should be located or protected so that there is no possibility of
accidental contact.
The transceiver should be mounted in a suitable position allowing easy operator
access. The antenna tuner should be mounted, preferably out of the weather, and
as close to the ground (earth) point as possible. The interconnect cable supplied
with the antenna tuner should be routed, away from other cables, back to the
transceiver and connected as indicated in the diagram.
The ground (earth) system is a key part of the overall antenna system and
consequently the system operation. An inadequate ground system is the primary
cause of poor performance and tuning problems. There is little point in installing
the antenna unless a good ground system can be provided. In areas of good
ground conductivity (ie. ground always damp), an effective ground can be made
through a grounding rod. This should be approx. 3 metres in length and should be
installed as close to the tuner as possible. Several rods bonded together will
improve the ground contact. In some cases metal water pipes may be used as a
ground providing:-
1.
The water pipe is close to the tuner and the water pipe enters the ground
close to the tuner.
2.
There are no joints or couplings in the pipe that will increase the resistance
path to ground.
