Furuno FCV295 - Manual (Page 39)

2. SYSTEM MENU
31
Bottom Level
In the default bottom level setting (0), the
equipment judges consecutive strong echoes
to be bottom echoes. If, in that setting, 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 distinguish bottom fish from the bottom
echo.
Zero Line
Turn the zero line (transmission line) on or off.
When turned off, the transmission line disap-
pears, which allows you to better watch fish
echoes near the surface. The length of the
transmission line changes with transducer
used and installation characteristics. If the
width of the transmission line is 4.5 ft (default
value) or more, set the transmission line width
with Zero Line Area, as follows.
Zero Line Area
This feature adjusts the rejection width of the
transmission line from the area specified
when the menu item Zero Line is turned off.
The effective range is 4.5 to 9.8 ft. For a long
tail, increase the value. If the transmission line
does not disappear, raise the STC or lower
the Tx power.
[HF], [LF]
Draft: The default depth display shows the
distance from the transducer. If you would
rather show the distance from the sea sur-
face, set your ship's draft.
Gain ADJ: If the gain is too high or too low, or
there is a difference in the gain between the
low and high frequencies, you can compen-
sate for it here.
Set the bottom level so that these
vertical lines just disappear.
0.0
1/2 MANUAL L:2.0/H:2.0 BL-LF
47.2
ft
Bottom lock display
20
40
60
0
45
Bottom
40
35