Raymarine SL72 Owner's Handbook Manual page 173

8-6
However, do not mount the scanner so high that it is affected by the pitching
and rolling of the vessel. In addition, you may need to lower the scanner to
avoid creating a shadow sector underneath the scanner's beam.
• Access: The scanner unit site should be easily accessible to allow mainte-
nance to be carried out safely.
• Magnetic compass: Mount the scanner unit at least 1 m away from a mag-
netic compass.
• Cable run: The maximum length of cable between the display unit and the
scanner unit should not normally exceed 20 m (60 ft) for radome scanners.
If you need to use a longer cable power cable lengths must be considered,
refer to Section 8.5 to determine appropriate lengths.
• Shadow sectors and false echoes: Mount the scanner away from large
structures or equipment, such as the fly bridge, large engine stacks, search-
lights, horns, or masts. It is particularly important to avoid shadow sectors
near the bow. Raising or even lowering the scanner may help to reduce
these effects.
In shadow areas beyond the obstruction there will be a reduction of the
beam intensity, although not necessarily a complete cut-off; there will be a
blind sector if the subtended angle is more than a few degrees.
In some shadow sectors the beam intensity may not be sufficient to obtain
an echo from a very small object, even at close range, despite the fact that a
large vessel can be detected at a much greater range. For this reason the
angular width and relative bearing of any shadow sector must be deter-
mined at installation. Sometimes shadowing can be seen by increasing the
radar gain until noise is present. Dark sectors indicate possible shadowed
areas. This information should be posted near the display unit and opera-
tors must be alert for targets in these blind sectors.
It should also be noted that wet sails create shadow areas and thus sail boat
operators should be aware that radar performance may reduce in rain.
If you mount the scanner on a mast, echoes from the mast may appear on
the radar display. These can be minimized by placing absorbing material,
such as a block of wood, between the scanner and mast.
• Platform rigidity/stability: The scanner platform should not twist
• Heat/fumes: Mount the scanner away from the top of exhaust stacks,
SL72 & SL72RC PLUS Pathfinder Radar & Radar/Chartplotter
(causing bearing errors) or be subject to excessive vibration.
since the scanner and cables can be damaged by excessive heat and the
corrosive effects of exhaust gases.