Erasing Weak Echoes; Measuring Depth - Furuno FCV-582L Operator's Manual

1.10 Erasing Weak Echoes

Dirty water or reflections from plankton may
be painted on the display in green or light-
blue. These weak echoes may be erased as
follows:
1. Press the SIG LEV key. The following
display appears.
SIGNAL LEVEL
OFF
SL1
SL2
SL3
SL4
SL5
SL6
(At 16-color display)
Figure 1-21 Signal level display
2. Press the SIG LEV key again to select sig-
nal level (echo color) to erase. The color
deleted disappears from the color bar and
is replaced with dark-blue color. SL1
erases the weakest echo; SL6 the light-
blue echo.
Figure 1-22 How SIG LEV works
SIGNAL LEVEL
OFF
SL1
SL2
SL3
(At 8-color display)
Weak
echoes
Signal level
adjusted

1.11 Measuring Depth

The VRM (Variable Range Marker) functions
to measure the depth to fish schools, etc.
1. Press the [ ] or [ ] key to place the
VRM on an echo.
2. Read the VRM range just above the VRM.
VRM (green)
49.6
Figure 1-23 How to measure depth
with the VRM
200k
0
0.0
20
39.8
40
60
80
9