NorthStar Navigation Echo Sounder NorthStar 491 - Manual (Page 2)

Contents
1 Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Welcome to the Northstar 491 . . . . . . . . . . . . 2
Using this manual . . . . . . . . . . . . . . . . . . . . . . 2
Technical support . . . . . . . . . . . . . . . . . . . . . . 4
How echo sounding works . . . . . . . . . . . . . . . 5
Powering the 491 on and off . . . . . . . . . . . . . 7
Setting up the 491 . . . . . . . . . . . . . . . . . . . . . 7
2 Quick Start: Using the Echo Sounder . . . . . . . . . 11
Displaying the echo sounder’s picture . . . . . 12
Using demo mode . . . . . . . . . . . . . . . . . . . . . 14
Introducing the displayed information . . . . 15
Using automatic mode . . . . . . . . . . . . . . . . . 16
Changing the frequency of echoes . . . . . . . 17
Zooming in and out . . . . . . . . . . . . . . . . . . . 19
Setup functions . . . . . . . . . . . . . . . . . . . . . . . 22
3 Adjusting the Echo Sounder Picture . . . . . . . . . 27
The picture menu . . . . . . . . . . . . . . . . . . . . . 28
Adjusting the gain (strong echoes) . . . . . . . . 28
Adjusting the clutter (weak echoes) . . . . . . . 29
Adjusting the signal level (weak echoes) . . . 30
Suppressing interference (the noise limiter) . 31
Selecting the color bar (hue) and white level 32
4 Understanding Depth Settings . . . . . . . . . . . . . . 35
Viewing the seabed depth . . . . . . . . . . . . . . 36
Viewing the depth marker . . . . . . . . . . . . . . 36
Changing the depth settings . . . . . . . . . . . . 36
Setting the picture’s shift (starting depth) . . 37
Setting the picture’s range . . . . . . . . . . . . . . 38
5 Other Functions: Using the MORE key . . . . . . . 41
Using the MORE key . . . . . . . . . . . . . . . . . . . 42
Changing the advance speed . . . . . . . . . . . . 42
Displaying the A-scope . . . . . . . . . . . . . . . . . 43
Setting the ECHO screen data . . . . . . . . . . . 44