Garmin GPSMAP 8700 Black Box Owners Manual - Page 38

• To scroll faster, select Up. • To scroll more slowly, select Down. Adjusting the Range of the Depth or Width Scale You can adjust the range of the depth scale traditional and Garmin ClearVü sonar views and the range of the width scale for the SideVü sonar view. Allowing the device to adjust the range automatically keeps the bottom within the lower or outer third of the sonar screen, and can be useful for tracking a bottom that has minimal or moderate terrain changes. Manually adjusting the range enables you to view a specified range, which can be useful for tracking a bottom that has large terrain changes, such as a drop-offs or cliffs. The bottom can appear on the screen as long as it appears within the range you have set. 1 From a sonar view, select Menu > Range. 2 Select an option: • To allow the chartplotter to adjust the range automatically, select Auto. • To increase or decrease the range manually, select Up or Down. TIP: From the sonar screen, you can select or to manually adjust the range. TIP: When viewing multiple sonar screens, you can select Select to choose the active screen. Sonar Noise Rejection Settings From a sonar view, select Menu > 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 Menu > Sonar Setup > Appearance. Color Scheme: Sets the color scheme. Color Gain: Adjusts the intensity of colors (Adjusting the Color Intensity, page 28). 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. 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 information. 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. 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 NOTE: Not all options are available on all transducers. From an applicable sonar view, select Menu > 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 30 Sonar Fishfinder