Performance characteristics | NorthStar Navigation NorthStar 491

A491 Features and Speciﬁcations

Table 4: 491 echo sounder features

Performance characteristics

Output	Single/Dual Channel, 50/200kHz, 600W

Alarms	Fish, seabed, temperature

Update rate	10 Hz maximum (depends on water depth)

Auto modes	Fishing and cruising

Zoom modes	Marker, bottom, bottom lock, bottom lock/center

Features	Mark present or past echo as waypoint (961/962)
	Go directly to any past echo
	A-scope analyzes present or past echoes
	Navigation data shown at bottom of screen
	Demo mode for training

491 Echo Sounder Operations Manual

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NorthStar Navigation NorthStar 491 manual A491 Features and Speciﬁcations, Performance characteristics

Contents

Northstar Echo Sounder Contents Troubleshooting 491 Operations Reviewing past echoes using SoundTracPage 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 Press the Port Setup Options key Using the 491 with the 957/958 961/962 echo sounder menu structure 957/958 echo sounder menu structure 2Quick Start Using the Echo Sounder Illustrated Echo screen Displaying the echo sounder’s picture Illustrated Soundtrac screen Chart Overlay screen Using demo modeAt the Chart Overlay Selection window, press Navigation Status tabs Depth and temperatureIntroducing the displayed information Echo sounding Cruising or ﬁshing Using automatic mode 50 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 lock zoom Using bottom zoom Using bottom lock/ center zoom Accessing the setup screen Setup functions Entering numerical values Number of special waypoints Changing the temperature graph’s units and scaleTransducer depth Changing the depth units 961/962 sensor setup screen Speed and temperature sensor setup 957958/ sensor setup screen 3Adjusting the Echo Sounder Picture Picture menu Adjusting the gain strong echoes Gain window Adjusting the clutter weak echoes Clutter window Adjusting the signal level weak echoes Suppressing interference the noise limiter Understanding the color bar Selecting the color bar hue and white level Hue and white level window Setting the white level Echo Sounder Operations Manual 4Understanding Depth Settings Viewing the depth marker Changing the depth settingsViewing the seabed depth Shift window Setting the picture’s shift starting depth Setting the picture’s range Range window Echo Sounder Operations Manual 5Other Functions Using the More key Changing the advance speed Using the More key Scope on single-frequency echo screen Displaying the A-scope Scope on dual-frequency echo screen Setting the Echo screen dataUsing the A-scope with dual frequencies Echo screen data selections Bottom depth box Temperature box Taking and storing a snapshot Temperature graphIntroducing snapshots Speed through the water Snapshot screen 961/962 only Archiving and restoring a snapshot with a ﬂoppy disk Archiving snapshots screen 961/962 only Archiving and restoring snapshots with a Zip disk Setting up the video image overlay Echo Sounder Operations Manual 6Reviewing past echoes using SoundTrac SoundTrac screen Viewing past echoes using SoundTrac Navigating to a past echo position Marking ﬁsh as waypoints Selected Cursor Position window appears Going directly to a past echo position 7Setting the Alarms Setting the ﬁsh alarm Understanding the alarms Fish alarm window Setting the upper and lower marker depths Turning the ﬁsh alarm on and off Setting the bottom alarmSetting inside or outside ﬁsh markers Alarm Bottom alarm window Setting the bottom level Temperature alarm window Setting the temperature alarmTurning the bottom alarm on and off Upper limit window is highlighted in black Turning the temperature alarm on and off When the temperature alarm sounds, an alert message is Troubleshooting the echo sounder Checking the transducer 8Troubleshooting 491 Operations No echoes displayed when Star key is pressed Troubleshooting the echo sounder OFF Checking the transducer Maintaining a transducer Manufacturer Model Power Northstar P/N Performance characteristics A491 Features and Speciﬁcations Interfacing Physical characteristicsEnvironmental characteristics Screen notations ON/OFF Manual controls Echo Sounder Operations Manual Glossary Echo Sounder Operations Manual