False echo at bottom
Images with a weak color similar to the bottom color may appear above the bottom
line when the bottom is steep or rubbed, or may appear below the bottom line when
the bottom is flat. Ultrasonic waves are emitted perpendicular to the transducer face.
Actually, a weak beam (sidelobe) is also emitted obliquely downward as shown in the
illustration below. When echoes reflected from this sidelobe are strong, false images
are displayed at the bottom.
3.22
System Menu
3.22.1 How to display the system menu
The system menu consists of items which do not require
frequent setting changes.
Touch control:
1.
Press the
MENU/ESC
key to open [MENU].
2.
Tap [SYSTEM].
Key control:
1.
Press the
MENU/ESC
key to open [MENU].
2.
Select [SYSTEM] with the arrow keys, then press the
ENTER
key.
3.22.2 Range menu
Change the factory default range if it is inappropriate for
the purpose of use.
Note:
When connecting multiple SFDs, the preset
values of all ranges need to be matched with
each other.
Mainlobe
Sidelobe
False image at bottom
3-36
3
.
FISH FINDER
