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Chapter 4. Screen view
4.1 The distance from the target to the height of target
The longest distance observable to the target is depending on the height of target,
the distance to the target and the height of antenna other than the matter of
performance like TX power, antenna beam width and receiving sensitivity. Radar
signal
is
linear
nature
that
is
affected
by
a
round
earth.
RADAR
TARGET
EARTH
A1
A2
A1 = 2.23 H1
A2 = 2.23 H2
A1+A2 = 2.23( H1+ H2)
A1, A2 : [NM]
H1, H2 : [m]
H2
H1
For example, when the height of antenna is 3 meters above sea level, the ECHO
image of i②land of 10 me③e①② heigh③ and 10 mile② away f①om ③he an③enna
may be
di②played on Sc①een b④③ ③he 5 me③e① ② heigh③ wi③h ②ame di②③ance i② no③
displayed on
screen since Radar signal transmitted does not reach.
But, these are of theoretical value and would not be constant due to environmental
condi③ion. In ③heo①y, ③he ③a①ge③ 10 mile② away f①om ③he an③enna ①eq④i①e② 7.6 me③e①②
height, if it is lower than 7.6 meter, ECHO image would not appear for which you
must keep in mind.
10m
5m
3m
10NM
10NM
화면에 표시 되지 않는
The island which is not displayed on Screen
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4.2 Reflection from the target
The strength of reflection from the target is related to not only the size of the target
but the shape and the materials composed of it. Therefore the strength of reflection
is not considered to be relative to the size of the target.
Especially it is dependant to the geographical condition in coastal line. If the
coastal line is flat slide, the only mountain summit is displayed on the screen as an
image, you should pay attention to the calculation of distance upto the coastal line.
The ECHO reflected from flat land is so weak that it is unlikely to observe such
land.
산
해안선
산
해안선
4.3 Wave Path
In case there is an obstruction in the course of wave path like Mountain, Rain and Snow,
the target behind of them may not be observed.
우설과 산으로 가려져 물표가
나타나지 않음
4.3.1
Reflection of sea level
On the sea surface where are made, white and broad images are displayed on the
screen center. This is a reflection created from the sea level and occurs as a
different image mainly depending on the size of wave, range and the direction of
wind.
The target does not appear due to
Snow and Mountain.
Coastal line
Mountain
Coastal line
Mountain
