Garmin GPSMAP 9000 Series, Руководство пользователя

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When targets are difficult to see , echo stretch makes the target returns more pronounced and easier to
see on the screen. If the echo stretch value is too high, the targets blend together. If the value is too low ,
the targets are small and more difficult to see.
You can use echo stretch and filter width together to obtain the preferable resolution and noise reduction.
With echo stretch and filter width set to low, the display has the highest resolution, but is the most
susceptible to noise. With echo stretch set to high and filter width set to low, the display has a lower
resolution, but has wider targets. With echo stretch and filter width set to high, the display has the lowest
resolution, but is the least susceptible to noise. It is not recommended to set echo stretch to low and filter
width to high.
Overlay Data: Sets the data shown on the sonar screen.
Sonar Alarms
WARNING
The sonar alarms feature is a tool for situational awareness only and may not prevent grounding in all
circumstances. It is your obligation to ensure safe operation of the vessel.
CAUTION
The Beeper setting must be turned on to make alarms audible ( Sounds and Display Settings, page 175 ). Failure
to set audible alarms could lead to injury or property damage.
NOTE: Not all options are available on all transducers.
From an applicable sonar view, select Options > Sonar Setup > Alarms.
You can also open the sonar alarms by selecting Settings > Alarms > Sonar.
Shallow Water: Sets an alarm to sound when the depth is less than the specified value.
Deep Water: Sets an alarm to sound when the depth is greater than the specified value.
FrontVü Alarm: Sets an alarm to sound when the depth in front of the vessel is less than the specified value,
which can help you avoid running aground ( Setting the FrontVü Depth Alarm, page 96 ). This alarm is
available only with Panoptix FrontVü transducers.
Water Temp.: Sets an alarm to sound when the transducer reports a temperature that is 2°F (1.1°C) above or
below the specified temperature.
Contour: Sets an alarm to sound when the transducer detects a suspended target within the specified depth
from the surface of the water and from the bottom.
Fish: Sets an alarm to sound when the device detects a suspended target.
• sets the alarm to sound when fish of all sizes are detected.
• sets the alarm to sound only when medium or large fish are detected.
• sets the alarm to sound only when large fish are detected.
Sonar Fishfinder 91