10
FISH450 Tricolor FISHFINDER
Installation and Operation Manual
NAVMAN
The
Sonar
screen displays the depth and strength
of the echos returned from each ultrasonic pulse.
This raw signal is enhanced by the
Colouration
and
Gain
settings and then displayed on the
Fish
History
or
Zoom
screen as a single vertical row of
dots.
The key to interpreting the
Sonar
screen is to look
at the strength (stronger echos project further to
the left) and the depth (distance down the screen)
of the echos.
Changing the colour thresholds
The
Colouration Bar
determines which level
(strength) of echos will be displayed in
blue
,
red
or
green
on the
Fish History
and
Zoom
screens.
To display the colouration bar, press the
Cursor
Left
or
Right
key.
• Increase the blue part of the colouration bar
by pressing the
Cursor Right
key if there are
too few blue (strong) echos being displayed.
• Decrease the blue part of the colouration bar
by pressing the
Cursor Left
key
if there are
too many blue echos
being displayed.
The red and green
portions of the bar graph
share the remaining area
equally.
The bar will automatically
turn off when left for four
seconds.
Manual Gain adjustment
The
Sonar
screen displays all echos returned. If
the
Manual Gain
value is high, the
Fish History
or
Zoom
screens may become cluttered with too
many weak echos. Use
Manual Gain
to adjust
the level of received echos that are displayed.
Holding the
Increase Gain
or
Decrease Gain
key
for one second or longer switches between
Auto
Gain
and
Manual Gain
. A dialogue box will
display “
Auto Gain
” or “
Manual Gain
”.
See the
Fish History
screen section 3-2 for more
information on
Manual Gain
adjustment.
3-3 Sonar screen
Unwanted weak signals
or ‘Noise’ (e.g. Bubbles)
Signals to the right of the
colouration bar are not
displayed on the
Fish
History
or
Zoom
screens.
Press the
Increase Gain
key to move the edge of
the colouration bar to
the right and display
more detail. Press the
Decrease Gain
key for
less detail.
This symbol and number (1 to 9) are
only displayed when in
Manual Gain
.
Small strong echo
(e.g. fish).
These usually flash
on and off as the
ultrasonic pulse
strikes the fish.
Large strong signal
(bottom).
Medium sized weak
signal (e.g. school of
small fish).
Strength
Depth
Blue
Red
Green
Increase the blue area by pressing
the
Cursor Right
key or decrease by
pressing the
Cursor Left
key
Not displayed
