Garmin GPSMAP 9000 Series, Owner'S Manual

Page: 104 / 232

Sonar Noise Rejection Settings
From a sonar view, select Options > Sonar Setup > Noise Reject.
Interference: Adjusts the sensitivity to reduce the effects of interference from nearby sources of noise.
The lowest interference setting that achieves the desired improvement should be used to remove
interference from the screen. Correcting installation issues that cause noise is the best way to eliminate
interference.
Color Limit: Hides part of the color palette to help eliminate fields of weak clutter.
By setting the color limit to the color of the undesired returns, you can eliminate the display of undesired
returns on the screen.
Smoothing: Removes noise that is not part of a normal sonar return, and adjusts the appearance of returns,
such as the bottom.
When smoothing is set to high, more of the low-level noise remains than when using the interference control,
but the noise is more subdued because of averaging. Smoothing can remove speckle from the bottom.
Smoothing and interference work well together to eliminate low-level noise. You can adjust the interference
and smoothing settings incrementally to remove undesirable noise from the display.
Surface Noise: Hides surface noise to help reduce clutter. Wider beam widths (lower frequencies) can show
more targets, but can generate more surface noise.
TVG: Adjusts the time varying gain, which can reduce noise.
This control is best used for situations when you want to control and suppress clutter or noise near the water
surface. It also allows for the display of targets near the surface that are otherwise hidden or masked by
surface noise.
Sonar Appearance Settings
From a sonar view, select Options > Sonar Setup > Appearance.
Color Scheme: Sets the color scheme.
Color Gain: Adjusts the intensity of colors (
Adjusting the Color Intensity, page 88 ).
A-Scope: Displays a vertical flasher along the right side of the screen that shows instantaneously the range to
targets along a scale.
Depth Line: Shows a quick-reference depth line.
Edge: Highlights the strongest signal from the bottom to help define the hardness or softness of the signal.
View Selection: Sets the direction of the Garmin SideVü sonar view.
Fish Symbols: Sets how the sonar interprets suspended targets.
Shows suspended targets as symbols and background sonar information.
Shows suspended targets as symbols with target depth information and background sonar informa­
tion.
Shows suspended targets as symbols.
Shows suspended targets as symbols with target depth information.
Pic. Advance: Allows the sonar picture to advance faster by drawing more than one column of data on
the screen for each column of sounder data received. This is especially helpful when you are using the
sounder in deep water, because the sonar signal takes longer to travel to the water bottom and back to the
transducer.
The 1/1 setting draws one column of information on the screen per sounder return. The 2/1 setting draws
two columns of information on the screen per sounder return, and so on for the 4/1 and 8/1 settings.
Echo Stretch: Adjusts the size of the echoes on the screen to make it easier to see separate returns on the
screen.
90 Sonar Fishfinder