APPENDIX
B
INSTALLATION
B.3
Installation Site
(1)
Scanner
The detection ability
of
shipborne
radar
ch nges greatly with the scanner location. The perfect
mounting location
is
as
high above the keel line
as
possible with
no
obstructions in
all
azimuthal
directions.
In
practice,
all
ships
are
subject
to
various limitations, and the
items
listed
below must
be
considered before selecting the mounting location.
(A)
The
maximum
detection distance increases with the height of the scanner installation location.
Install the scanner as high
as
possible
after
considering the
ship
construction and scanner
main
-
tainability.
(B)
If
the scanner
is
installed at the same height as part
of
a funnel
or
mast,
the
radar
pulse
will
be
blocked
resulting in a blind
spot
or ghosting; avoid
this
type
of installation location
if
at
all
possible.
(C)
To
avoid formation
of
blind
spots
or ghosting, install
scanner
closer to the ship's bow than any
other
obstacle like a mast or funnel.
If
it is impossible to avoid obstacles
in
the bow
direction
because
of
the ship construction, install
the scanner
off
the keel line
or
elevate the position
so
that a
dip
angle can
be
taken.
Method
for
installing
scanner
off
keel
line
Displacing the
scanner
to
the
starboard
side
of
the
ship
moves the blind spot
to
the
port
side
on
the
radar
display
and
gives a clear view
in
the
bow
direction.
The displacement can
be
found
from
the
following
equations.
Method calculating
dip
angle
Install the
scanner
as
high
as
possible
so
that a sufficient
dip
angle
(
0
)
can
be
obtained
between the line
of
sight between the
scanner
and
obstacle, and a
horizontal
line.
To
prevent
blind
spots
in the medium to long range, the
dip
angle
should
be
greater
than
5'
.
Objects
below the line
of
sight
from
the
scanner
to the
obstacle
cannot
be
detected.
Horizontal
line
Line of sight
e
I
(E)
Install the scanner where it
will
not
be
affected
by smoke
of
hot
gas
from
the funnel or by heat
Keep the antenna as
far
away as possible
from
direction
-
finding equipment and
VHF
antennas.
(G)
Install the scanner
within
the 10
-
meter length
of
the standard connection cable.
If
this
is not
40
from
spotlights,
etc.
possible, the
maximum
length
is
100
m.
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