１－5
SONAR SYSTEM SUMMARY
TILT ANGLE AND DISPLAY
In the shallow water the bottom reflection is prominent, so it is important to be able
to distinguish fish echoes from the bottom echo. Therefore the setting of the tilt angle
is important to find out the suitable tilt angle.
The below shows how fish schools are displayed on the screen when each different
tilt angle set. The below drawings are shown under Off-Center position.
FISH SCHOOL
②
FISH SCHOOL
FISH SCHOOL
④
SEA BOTTOM
SEA BOTTOM
SEA BOTTOM
TILT ANGLE –40° TILT ANGLE –25° TILT ANGLE –10°
・
TILT ANGLE 40° :
Fish school is just above the bottom echo so that it is
hard to discriminate fish echo from the bottom, since the
distances from fish school and from bottom are the same.
・
TILT ANGLE 25° :
Fish school is clearly seen. Fish school is displayed
behind the bottom echo, since fish school is in the area
of weak reflection of bottom echo.
・
TILT ANGLE 10° :
Bottom echo is weak so that fish school is easily seen.
Due to the density of fish school the strong reflection of fish
school is easily displayed on the screen.
Fish school
③
is actually in the middle layer, however it is
displayed likely to be near the bottom echo on the screen.
NOTE !---------------------------------------------------------------------------------------------------------
The explanation mentioned above is extremely general explanation, and it is
not a thing satisfying all conditions, which is different depending on the
situation of the sea and a state of the bottom of the sea, setting of sensitivity
and so on.
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FISH SCHOOL
①
FISH SCHOOL
③
SEA BOTTOM
－４０゜
－２５゜
－１０゜
①
②
③
④
＋
＋
＋
