Furuno NAVNET 1933C-BB - Manual (Page 28)

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1.5 Mounting the Antenna Unit of
MODEL1933C-BB/1943C-BB/1953C-BB
Mounting considerations
•
The antenna unit is generally installed either on top of the wheelhouse or on the radar
mast on a suitable platform. Locate the antenna unit where there is a good all-round view.
Any obstruction will cause shadow and blind sectors. A mast for instance, with a diameter
considerably less than the width of the radiator, will cause only a small blind sector, but a
horizontal spreader or crosstrees in the same horizontal plane as the antenna unit would
be a much more serious obstruction; you would need to place the antenna unit well
above or below it.
•
It is rarely possible to place the antenna unit where a completely clear view in all
directions is available. Thus, you should determine the angular width and relative bearing
of any shadow sectors for their influence on the radar at the first opportunity after fitting.
•
To lessen the chance of picking up electrical interference, avoid where possible routing
the signal cable near other onboard electrical equipment. Also avoid running the cable in
parallel with power cables.
•
A magnetic compass will be affected if the antenna unit is placed too close to the
magnetic compass. Observe the following compass safe distances to prevent deviation of
a magnetic compass: Standard compass, 1.00 m, Steering compass, 0.80 m (1953C-BB:
0.75 m).
•
Do not paint the radiator aperture, to ensure proper emission of the radar waves.
a) When this radar is to be installed on larger vessels, consider the following points:
The signal cable run between the antenna and the processor units comes in lengths of
10 m, 15 m, 20 m and 30 m.
b) Deposits and fumes from a funnel or other exhaust vent can adversely affect the aerial
performance and hot gases may distort the radiator portion. The antenna unit must not
be mounted where the temperature is more than 70°C.
As shown in the figure below, the antenna unit may be installed on the bridge, on a common
mast or on the radar mast.
(a) On bridge (b) Common mast (c) Radar mast