Fish alarm window | NorthStar Navigation NorthStar 491 instruction

Setting the alarm’s echo strength level

Setting the upper and lower marker depths

4.Follow the instructions below for each of these ﬁve settings.

Fish alarm window

To set the fish alarm’s minimum echo-strength level:

1.At the FISH ALARM window, press SET ALARM LEVEL.

2.Press the CURSOR PAD up and down to set the echo strength level from 1 to 15, as represented on the vertical color bar.

Echoes received that are strong enough to be within the crosshatched area on the vertical bar will cause an alarm (weaker echoes will be ignored).

The fish alarm will sound only when there are echoes inside (or optionally, outside) the upper and lower markers. These markers are displayed on the ECHO screens.

To set the depth of the upper marker:

1.At the FISH ALARM window, press SET UPPER MKR.

The upper marker window is highlighted in black.

491 Echo Sounder Operations Manual

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NorthStar Navigation NorthStar 491 manual Setting the upper and lower marker depths, Fish alarm window

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 957/958 961/962 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 At the Chart Overlay Selection window, press Using demo modeChart Overlay screen Introducing the displayed information Depth and temperatureEcho sounding Navigation Status tabs Cruising or ﬁshing Using automatic mode Changing 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 zoom Using bottom lock/ center zoom Accessing the setup screen Setup functions Entering numerical values Transducer depth Changing the temperature graph’s units and scaleChanging the depth units Number of special waypoints 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 seabed depth Changing the depth settingsViewing the depth marker 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 Using the A-scope with dual frequencies Setting the Echo screen dataScope on dual-frequency echo screen Echo screen data selections Bottom depth box Temperature box Introducing snapshots Temperature graphSpeed through the water Taking and storing a snapshot 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 Setting inside or outside ﬁsh markers Setting the bottom alarmAlarm Turning the ﬁsh alarm on and off Bottom alarm window Setting the bottom level Turning 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 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 Environmental characteristics Physical characteristicsScreen notations Interfacing ON/OFF Manual controls Echo Sounder Operations Manual Glossary Echo Sounder Operations Manual