Furuno CH-37 - Manual (Page 20)

2-4
2.4 Setting the Tilt Angle
The tilt angle shows the direction to which the sound wave is
emitted. When the sound wave is emitted horizontally, the tilt
angle is said to be 0
°
and when emitted vertically, 90
°
.
To set a tilt angle, operate the TILT control. Watch the tilt angle
indication at the top right corner of the screen. The tilt angle
can be set in one-degree steps from -5
°
(upward) to 60
°
(down-
ward).
Finding a proper tilt angle is important when searching for fish.
Bottom echo and tilt angle
Case 1: Tilt angle 30
°
to 40
°
This tilt angle will display the entire bottom since it is captured
by the full width of the beam.
Case 2: Tilt angle 10
°
to 20
°
This tilt angle will only display half the bottom since it is only
captured by the lower half of the beam.
Case 3: Tilt angle 0
°
to 5
°
This tilt angle may or may not capture the bottom since the
returning echo is weak.
How to discriminate fish echoes from the bottom
The figure at the top of the next page illustrates how two fish
schools
a and b are displayed on the screen using three dif-
ferent tilt angles.
Case 1: Tilt angle 30
°
to 40
°
. Fish school is obscured by the
bottom.
Case 2: Tilt angle 10
°
to 20
°
. Fish school is located above the
bottom (midwater).
Case 3: Tilt angle 0
°
to 5
°
. Fish school is located close to the
bottom.