Furuno CH-270 - Manual (Page 27)

2. HORIZONTAL MODE
2-7
2.6.2 Relation between tilt angle and echo
Refer to the illustration below to see the relation between tilt angle and bottom echo.
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.
The figure below illustrates how two fish schools “a” and “b” are displayed on the screen
using three different 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.
Case 1 Case 2 Case 3
Bottom
Case 1
Bottom
Case 2 Case 3
Bottom
Fish school "b"
Fish school "a" Fish school "a" Fish school "a"
Fish echo and tilt angle