NorthStar Navigation NorthStar 491 manual Using bottom lock/ center zoom

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Using bottom lock/ center zoom

When you select bottom lock/center zoom, the sea bottom is flattened out and displayed in the center of the screen. You can see any fish near the bottom, as with the bottom lock zoom, and also examine the seabed’s composition.

Using marker zoom When you select marker zoom, you can choose the part of the water column to magnify. The top edge of the magnified area

is determined by the location of the depth marker. To move

491 Echo Sounder Operations Manual

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Contents Northstar Echo Sounder Contents Troubleshooting 491 Operations Reviewing past echoes using SoundTracPage 1Welcome Welcome to the Northstar Using this manualOrganization Conventions Technical support Service and repairHearing from you How echo sounding works 961/962 echo sounder system components Setting up Powering the 491 on and offUsing 491 with the 961/962 Press the Port Setup Options key Using the 491 with the 957/958961/962 echo sounder menu structure 957/958 echo sounder menu structure 2Quick Start Using the Echo Sounder Illustrated Echo screen Displaying the echo sounder’s pictureIllustrated Soundtrac screen At the Chart Overlay Selection window, press Using demo modeChart Overlay screen Introducing the displayed information Depth and temperatureEcho sounding Navigation Status tabsCruising or ﬁshing Using automatic modeChanging the frequency of echoes Manually overriding automatic mode50 kHz 200 kHz Echo screen with both frequencies displayed Zooming in and out Choosing a zoom modeChoosing the zoom scale Using bottom lock zoom Using bottom zoomUsing bottom lock/ center zoom Accessing the setup screen Setup functionsEntering numerical values Transducer depth Changing the temperature graph’s units and scaleChanging the depth units Number of special waypoints961/962 sensor setup screen Speed and temperature sensor setup957958/ sensor setup screen 3Adjusting the Echo Sounder Picture Picture menu Adjusting the gain strong echoesGain window Adjusting the clutter weak echoesClutter window Adjusting the signal level weak echoesSuppressing interference the noise limiter Understanding the color bar Selecting the color bar hue and white levelHue and white level window Setting the white levelEcho Sounder Operations Manual 4Understanding Depth Settings Viewing the seabed depth Changing the depth settingsViewing the depth marker Shift window Setting the picture’s shift starting depthSetting the picture’s range Range window Echo Sounder Operations Manual 5Other Functions Using the More key Changing the advance speed Using the More keyScope on single-frequency echo screen Displaying the A-scopeUsing the A-scope with dual frequencies Setting the Echo screen dataScope on dual-frequency echo screen Echo screen data selections Bottom depth box Temperature boxIntroducing snapshots Temperature graphSpeed through the water Taking and storing a snapshotSnapshot screen 961/962 only Archiving and restoring a snapshot with a ﬂoppy diskArchiving snapshots screen 961/962 only Archiving and restoring snapshots with a Zip diskSetting up the video image overlay Echo Sounder Operations Manual 6Reviewing past echoes using SoundTrac SoundTrac screen Viewing past echoes using SoundTracNavigating to a past echo position Marking ﬁsh as waypointsSelected Cursor Position window appears Going directly to a past echo position7Setting the Alarms Setting the ﬁsh alarm Understanding the alarmsFish alarm window Setting the upper and lower marker depthsSetting inside or outside ﬁsh markers Setting the bottom alarmAlarm Turning the ﬁsh alarm on and offBottom alarm window Setting the bottom levelTurning the bottom alarm on and off Setting the temperature alarmTemperature alarm window Upper limit window is highlighted in black Turning the temperature alarm on and offWhen the temperature alarm sounds, an alert message is Troubleshooting the echo sounder Checking the transducer 8Troubleshooting 491 OperationsNo echoes displayed when Star key is pressed Troubleshooting the echo sounderOFF Checking the transducerMaintaining a transducer Manufacturer Model Power Northstar P/NPerformance characteristics A491 Features and SpeciﬁcationsEnvironmental characteristics Physical characteristicsScreen notations InterfacingON/OFF Manual controlsEcho Sounder Operations Manual Glossary Echo Sounder Operations Manual