Northstar
M121/M84
Installation and Operation Manual
75
Press
MENU
twice, then select
Sonar
:
Frequency
There is a choice of:
200 kHz
,
50 kHz
and
Mixed
. For information about selecting a
suitable frequency for the water conditions, see
section 9-3.
Scroll speed
Use this to set the scroll speed on the display.
There is a choice of:
Very Fast
,
Fast
,
Medium
,
Slow
and
Pause.
The depth of
the water also affects the speed of the display.
Faster scroll speeds combined with a slow
boat speed (typically between 2 and 6 knots)
shows the most fish detail.
Medium
or
Slow
scroll speeds result in sonar information being
displayed over a longer period, but with less
detail (see Section 9-2).
Fish symbols
The Instrument always displays echoes from
fish (fish arches, see section 9-4). If fish symbols
are on, a symbol is displayed over the arch (see
section 9-4). The options are:
•
Off
: No fish symbol is displayed.
•
Fun
or
Normal
: A fish symbol is displayed.
19-3 Setup > Sonar
Fish depth labels
When this is turned on, the depth of a fish is
printed next to the fish arch.
Fish filter
Use this to select the minimum fish size that will
be displayed as a fish symbol and to trigger the
Fish alarm. The options are:
Small
,
Medium
and
Large
.
Fish sensitivity
Selects the minimum strength fish echo that
will be displayed as a fish symbol. Higher values
will display more fish symbols.
Digit size
Use this to remove or change the size of the
depth window on the sonar windows. There is a
choice of:
Small
,
Medium
and
Large
.
Palette
Use this to select a color palette. Each color
within the palette represents a different echo
strength, as shown on the sonar windows.
There is a choice of five color palettes:
Black
,
Blue
,
White
,
Vivid
and
8 color
. The first
four palettes display more detail, and each color
covers a 1.5 dB signal range. The
8 color
palette displays less detail, and each color
covers a 3 dB signal range.
Interference filter
No filter, normal setting.
Filters the echo signal to remove spiky
interference such as engine noise or depth
sounders on nearby boats.