Furuno FCV-1900 Operator's Manual page 60

2. SYSTEM MENU
[Bottom Level]: In the default bottom level set-
ting (+0), the equipment judges consecutive
strong echoes to be bottom echoes. If, in that set-
ting, the depth indication is unstable, adjust the
bottom level. If vertical lines extend upward from
the bottom echo in the bottom lock display, lower
the bottom level to erase the vertical lines. If the
level is too low, however, it may be difficult to dis-
tinguish bottom fish from the bottom echo.
[Zero Line Rejection]: Turn the zero line (trans-
mission line) on or off. When turned on, the trans-
mission line disappears, which allows you to see
fish echoes near the surface clearly. The length
of the transmission line changes with transducer
used and installation characteristics. If the width of the transmission line is 0.4 m (de-
fault value) or more, set the transmission line width with [Zero Line Area], as below.
[Zero Line Area]: This feature adjusts the transmission line so that the transmission
line disappears when the menu item [Zero Line Rejection] is turned on. For a long tail,
increase the value. If the transmission line does not disappear, lower the TX power.
[Zero Line Fill]: Turn off to see fish echoes within 1 m from the surface.
[Draft]: The default depth display shows the distance from the transducer. If you would
rather show the distance from the sea surface, set your ship's draft. The draft line for
HF and LF can be set respectively.
[Gain ADJ]: If the gain is too high or too low, or the gain for the low and high frequen-
cies appears unbalanced, you can compensate it here.
[Fish Size]: Compensate for wrongful indication of fish size.
2-10
Setting value Compensation size
+500%
+400%
+300%
+200%
+100%
+50%
-50%
-65%
-75%
-80%
Bottom lock display
1 1 1
x x x
LF_BL
31.2 31.2
ft ft
Bottom
Set the bottom level so that these
vertical lines just disappear.
Sextuple
Quintuple
Quadruple
Triple
Double
1.5
1/2
1/3
1/4
1/5
0/99 VRM 0.0
0 0
0.0 0.0
LF: 2.0
5 5
4 4
10 10
3 3
20 20
2 2
30 30
1 1
0 0
40 40