Speed Calibrate; Temperature Calibrate; Sonar History; Sonar Interference Rejection - Raymarine DSM250 Owner's Handbook Manual

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Speed Calibrate

Temperature Calibrate

Sonar History

Sonar Interference Rejection

If the transducer is equipped with a speed paddle wheel, the
DSM250 calculates the speed of the boat through the water. The
speed calibrate option enables you to adjust the displayed speed
so that it matches your actual speed through the water. You can
adjust the displayed speed from 1% to 200%.
If the sounder reading is too low, set Speed Calibration to more
than 100%. If the sounder reading is too high, set Speed Calibra-
tion to less than 100%.
If the transducer is equipped with a thermistor, the DSM250 cal-
culates the temperature of the water. The temperature calibrate
option enables you to adjust the displayed temperature. You can
adjust the displayed temperature by -9.0°F to +9.0°F.
Sonar History determines the number of data sample columns that
appear on the screen at one time. The options are: SMALL, which
displays 240 columns of data or LARGE, which shows 480 col-
umns.
Information displayed in a single column using the LARGE setting
would occupy two columns with SMALL. As a result, twice as
much data history is displayed under the LARGE setting. Data dis-
played using SMALL appears wider and scrolls across the screen
faster.
Two or more sonar-equipped vessels operating within range of
each other can create interference on the sounder screen. This
usually appears as vertical streaks in the water that do not repre-
sent actual targets.
The DSM250 includes a SONAR INT REJ option that can reduce
such interference, either manually or automatically. LOW rejects
only a small amount of the extraneous objects. Use this setting
when you want to be sure that what has been removed are really
false returns.
DSM250 Digital Sounder Module