Furuno NAVIONICS GP-1850F - Manual (Page 19)

2-5
2.5 Automatic Sounder
Operation
Automatic sounder operation is useful when
you are preoccupied with other tasks and do
not have time to adjust the display.
How the automatic sounder works
The automatic sounder function automatically
selects the proper gain, range scale and clut-
ter suppression level according to depth. It
works as follows:
• Range changes automatically to locate the
bottom on the lower half of screen. It jumps
to one step shallower range when bottom
echoes reach a half way point of the full
scale from top and to one step deeper
range when they come to the lower edge
of scale.
• The gain is automatically adjusted to dis-
play the bottom echo in reddish brown (de-
fault color arrangement).
• Clutter, which suppresses low level noise,
is automatically adjusted.
Two types of automatic sounder
modes
Two types of automatic sounder modes are
available: CRUISING and FISHING. CRUIS-
ING is for tracking the bottom, and FISHING
is for searching fish schools. CRUISING uses
a higher clutter rejection setting than FISH-
ING therefore it is not recommended for fish
detection - weak fish echoes may be erased
by the clutter suppression circuit.
How to enable automatic sounder
operation
1. To show the mode/freq window:
Normal sounder display: Press the soft
key MODE/FREQ.
Plotter/sounder display: Press the soft
key SNDR, MODE/FREQ in order.
Dual-frequency display: Press the soft
key MODE.
MODE/FREQ
▲
' AUTO CRUISING
™ AUTO FISHING
™ MANUAL
▼
Figure 2-14 Mode/frequency window
2. Press ▲ or ▼ to select AUTO CRUISING
or AUTO FISHING.
3. Press the soft key RETURN to close the
window automatically, or wait 10 seconds
and the window closes automatically.
2.6 Manual Sounder
Operation
Manual operation is useful for observing fish
schools and bottom using fixed gain setting.
The gain, range and range shifting functions
used together give you the means to select
the depth you can see on screen. The basic
range can be thought of as providing a “win-
dow” into the water column and range shift-
ing as moving the “window” to the desired
depth.
Selecting the manual mode
1. Press the appropriate soft key to show
the mode/freq window.
2. Select MANUAL.
3. Press the soft key RETURN.