Mounting; Antenna Unit - Furuno FR-8122 Installation Manual

1. MOUNTING

1.1 Antenna Unit

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 horizontal beamwidth 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 it. Observe
the compass safe distances mentioned in the SAFETY INSTRUCTIONS to prevent
interference to a magnetic compass.
• Do not paint the radiator aperture, to ensure proper emission of the radar waves.
• When this radar is to be installed on larger vessels, consider the following points:
• The signal cable run between the antenna and the display units comes in lengths of
10 m, 15 m, 20 m and 30 m.
• 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
Mounting methods
(c) Radar mast
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