Using Alarms - Raymarine DSM300 User Manual

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STC
STC (Sensitivity Time Control) reduces surface clutter by reducing the gain in the
GAIN
top 100 ft of the display. This function is useful for reducing noise (caused by air
bubbles and floating debris) that often appears in shallow water. A low STC value
has little effect on gain in shallow water; a high STC value decreases the gain in
MANUAL
shallow water so that only the strongest echoes are displayed.
Although you can manually set the STC level, Raymarine recommends letting the
15%
sounder module choose the proper level for you by selecting AUTO STC.
Automatic STC mode takes advantage the hardware's advanced DSP technology,
STC
which typically achieves a sharper image in auto mode than is possible in manual
mode.
STC is not available in Sonar Simulator mode.

Using Alarms

The ALARMS key is used to set up alarms; three alarms are available to alert you
ALARMS
of fish, shallow water, and deep water. Each alarm can be toggled ON and OFF
and you set the depth at which shallow and deep water alarms are triggered:
ranging from 2–3000 ft (or 2–4900 ft for high performance transducers).
You may want to use the shallow and deep water alarms when you are anchored.
Set the limits to just above and below your anchor depth; the sounder triggers an
alarm if the anchor drags and the boat moves into shallower or deeper water.
• Fish Alarm – If this alarm is ON the unit sounds a buzzer whenever it finds a
fish. Different buzzer tones are used to indicate fish detected by the 50 kHz
and 200 kHz frequencies.
• Shallow water – You set depth at which the shallow water alarm triggers.
When the depth is less than that set, the buzzer sounds and a pop-up window
describing the alarm is displayed. You cannot set the shallow alarm to be
deeper than the deep alarm.
• Deep water – You set depth at which the deep water alarm triggers.When the
depth is more than that set, the buzzer sounds and a pop-up window describ-
ing the alarm is displayed. You cannot set the deep alarm to be shallower than
the shallow alarm.
Note: The Deep Alarm must be set at a depth that is greater than the depth at which the
Shallow Alarm is set. Conversely, the Shallow Alarm must be set at a depth that is less than
the depth at which the Deep Alarm is set.
After you have acknowledged the sounding of a shallow or deep water alarm, a
minimum of 30 seconds must elapse before a another shallow/deep alarm can
sound again.
DSM300 Operation with PLUS Series Displays