Marine GPS System User Manual

2-5
2.6 Sounder Displays
Five sounder displays are available: normal,
marker zoom, bottom zoom, bottom-lock and
A-scope display. You may select a sounder
display with the SNDR key.
Selecting a sounder display
1. Press the SNDR key. The SELECT
SOUNDER MODE screen appears.
SELECT SOUNDER MODE
SNDR: Sel ESC: Close
Normal
Marker Zoom
Bottom Zoom
Bottom Lock
A-Scope
50kHz
200kHz
Figure 2-12 Select sounder mode screen
2. Press the SNDR key again to select a
sounder mode. Each time the key is
pressed the sounder mode changes in the
following sequence:
Normal Marker Zoom
Bottom Zoom
Bottom-LockA-Scope
You may also select a sounder mode by press-
ing ▲ or ▼ and the ENT key.
3. Press the ESC key to conclude your se-
lection.
Normal sounder display
50 kHz
The sounder uses ultrasonic pulses to detect
seabed conditions. The lower the frequency
of the pulse, the wider the detection area.
Therefore, the 50 kHz frequency is useful for
general detection and judging seabed condi-
tion.
50 kHz
200 kHz
Figure 2-13 Detection area
200 kHz
The higher the frequency of the ultrasonic
pulse the better the resolution. Therefore, the
200 kHz frequency is ideal for detailed ob-
servation of fish schools.
200k
162
0
50
100
150
200
68.3
CSE 180.0° SPD 16.8kt
DEP 162m TMP 16.0 °C
2D
13:41
POS 34° 26.245' N 135° 41.232' E
°C
30
20
10
0
Depth
Color
bar
Water
temp.
graph
Temp.
scale
Water temp. display
Depth scale
Variable
Range
Marker
(white)
Fish
school
Bottom
Tx
frequency
Figure 2-14 Typical 200 kHz normal
sounder display