Blind And Shadow Sectors - Furuno 1832 Operator's Manual

Direct
path
Indirect
path
Obstruction
(mast, funnel.
Antenna
etc.)
Target
Indirect
path
Direct
path
Own
ship
True
echo
Bridge
Indirect
echo
Figure 4-3 Indirect echoes
Heading
line
Target
True
echo
Indirect
echo
Heading
line
Indirect
echo

4.4 Blind and Shadow Sectors

Funnels, stacks, masts, or derricks in the path
of antenna may reduce the intensity of the ra-
dar beam. If the angle subtended at the antenna
is more than a few degrees a blind sector may
be produced. Within the blind sector small tar-
gets at close range may not be detected while
larger targets at much greater ranges may be
detected. See Figure 4-4.
Vessel taller
than wharf
Wharf
Wharf
Blind sector
(no echo)
Figure 4-4 Blind and shadow sectors
Mast, etc. in
path of radar
beam
Size of blind sector
depends on target
size and range.
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