Raymarine DSM250, Owner'S Handbook Manual

Page: 18 / 122

1-8 DSM250 Digital Sounder Module
Note: Receiving and displaying position data requires that a GPS is
connected to your Raymarine system.
Figure 1-4: Half-Screen Windows in Sonar Mode
Details on selecting windows are given in Chapter 3 .
For details on the radar, chartplotter or fishfinder display, please
refer to the Owner’s Handbook supplied with that unit.
Sonar Options
The DSM250 provides controls to select additional modes:
• Frequency – you can select the transducer frequency: 50 kHz for
wide coverage and deep water, 200 kHz for a detailed view, both
frequencies simultaneously or auto-frequency. The default set-
ting is auto-frequency, which determines the optimum frequency
of operation based on the current depth.
• Bottom Lock – changes the operating mode to re-set the bottom.
It provides a bottom-up view: the bottom is used as the reference,
its image is flattened and depths are displayed here.
Bottom lock mode is used primarily to filter out the bottom struc-
ture and display fish details only.
• A-Scope – displays a real-time image of the bottom structure and
fish directly below the transducer. The A-Scope window also dis-
plays the patented Bottom Coverage width indication.
ZOOM FREQUENCY BTM.LOCK A-SCOPE
AUTO GCRZFH
50kHz
0
60
STEER PORT
WAYPOINT 001
XTE
WPT BRG
WPT RNG
TTG
0.28
nm
26.8
nm
03
h
:59
m
351°
T
20
40
ZOOM FREQUENCY BTM.LOCK A-SCOPE
AUTO GC FH
50kHz
0
DEPTH
ft
SPEED
kts
20.1
15.1
10.1
F
30 0 MINUTES
20
40
TEMPERATURE
ft
60 60
Horizontal Half-Screen
D6206-1
Vertical Half-Screen