NorthStar Navigation NorthStar 491 manual Using automatic mode, Cruising or ﬁshing

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Using automatic mode

To operate the echo sounder automatically, just press AUTO. All of the 491’s adjustments will be set to produce a useful picture under most conditions. When you’re too busy to optimize the settings manually, the echo sounder can automatically set the optimal gain, clutter, and range settings, to show an excellent picture, from the surface to the bottom.

When you select auto, the range setting may change from time to time to keep the seabed in view as the water depth changes.

	It is recommended that the 491 be operated automatically
	whenever possible. The 491 can reliably detect the seabed
	depth only when it controls the gain and clutter settings.
	You can always press AUTO on the ECHO screen to remove
	any manual settings you’ve made and return to the standard
	automatic configuration.
Cruising or ﬁshing	Automatic mode has two variations: autocruising and
	autofishing.
	• autocruising optimizes the gain and clutter for tracking
	the bottom, with less emphasis on any ﬁsh in the water
	• autoﬁshing optimizes the gain and clutter for searching
	for ﬁsh
	Press AUTO to switch between autocruising and autofishing.
	The colored tab below the menu key indicates whether the
	unit is optimized for cruising or fishing.
The status tabs	Colored status tabs just below the AUTO and PICTURE keys
	are green when the echo sounder is operating fully
	automatically. They turn yellow when any of the settings has
	been set manually. (In some cases, the picture tab may be
	yellow while the auto tab is still green, if the Noise Limiter is
	turned on, for example.)

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491 Echo Sounder Operations Manual

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Contents Northstar Echo Sounder Contents Reviewing past echoes using SoundTrac Troubleshooting 491 OperationsPage 1Welcome Organization Using this manualWelcome to the Northstar Conventions Hearing from you Service and repairTechnical support How echo sounding works 961/962 echo sounder system components Using 491 with the 961/962 Powering the 491 on and offSetting up Using the 491 with the 957/958 Press the Port Setup Options key961/962 echo sounder menu structure 957/958 echo sounder menu structure 2Quick Start Using the Echo Sounder Displaying the echo sounder’s picture Illustrated Echo screen Illustrated Soundtrac screen Chart Overlay screen Using demo modeAt the Chart Overlay Selection window, press Depth and temperature Introducing the displayed informationEcho sounding Navigation Status tabsUsing automatic mode Cruising or ﬁshing50 kHz 200 kHz Manually overriding automatic modeChanging the frequency of echoes Echo screen with both frequencies displayed Choosing the zoom scale Choosing a zoom modeZooming in and out Using bottom zoom Using bottom lock zoomUsing bottom lock/ center zoom Setup functions Accessing the setup screenEntering numerical values Changing the temperature graph’s units and scale Transducer depthChanging the depth units Number of special waypointsSpeed and temperature sensor setup 961/962 sensor setup screen957958/ sensor setup screen 3Adjusting the Echo Sounder Picture Adjusting the gain strong echoes Picture menuAdjusting the clutter weak echoes Gain windowAdjusting the signal level weak echoes Clutter windowSuppressing interference the noise limiter Selecting the color bar hue and white level Understanding the color barSetting the white level Hue and white level windowEcho Sounder Operations Manual 4Understanding Depth Settings Viewing the depth marker Changing the depth settingsViewing the seabed depth Setting the picture’s shift starting depth Shift windowSetting the picture’s range Range window Echo Sounder Operations Manual 5Other Functions Using the More key Using the More key Changing the advance speedDisplaying the A-scope Scope on single-frequency echo screenScope on dual-frequency echo screen Setting the Echo screen dataUsing the A-scope with dual frequencies Bottom depth box Temperature box Echo screen data selectionsTemperature graph Introducing snapshotsSpeed through the water Taking and storing a snapshotArchiving and restoring a snapshot with a ﬂoppy disk Snapshot screen 961/962 onlyArchiving and restoring snapshots with a Zip disk Archiving snapshots screen 961/962 onlySetting up the video image overlay Echo Sounder Operations Manual 6Reviewing past echoes using SoundTrac Viewing past echoes using SoundTrac SoundTrac screenMarking ﬁsh as waypoints Navigating to a past echo positionGoing directly to a past echo position Selected Cursor Position window appears7Setting the Alarms Understanding the alarms Setting the ﬁsh alarmSetting the upper and lower marker depths Fish alarm windowSetting the bottom alarm Setting inside or outside ﬁsh markersAlarm Turning the ﬁsh alarm on and offSetting the bottom level Bottom alarm windowTemperature alarm window Setting the temperature alarmTurning the bottom alarm on and off Turning the temperature alarm on and off Upper limit window is highlighted in blackWhen the temperature alarm sounds, an alert message is 8Troubleshooting 491 Operations Troubleshooting the echo sounder Checking the transducerTroubleshooting the echo sounder No echoes displayed when Star key is pressedChecking the transducer OFFManufacturer Model Power Northstar P/N Maintaining a transducerA491 Features and Speciﬁcations Performance characteristicsPhysical characteristics Environmental characteristicsScreen notations InterfacingManual controls ON/OFFEcho Sounder Operations Manual Glossary Echo Sounder Operations Manual