User manual NORTHSTAR 491 ECHOSOUNDER

[. . . ] Northstar 491 Echo Sounder Operations Manual This manual is for using the 491 sounder with the Northstar 957, 958, 961 and 962 navigators. For the Northstar 6000i, information in Section 6 of its manual can be used instead. Revision A Part Number GM494 Northstar 30 Sudbury Road Acton, Massachusetts 01720 a unit of Brunswick New Technologies Marine Electronics www. NorthstarNav. com Service: 978/897-6600 Sales: 800/628-4487 Contents 1 Welcome . . 12 14 15 16 17 19 22 28 28 29 30 31 32 36 36 36 37 38 42 42 43 44 3 Adjusting the Echo Sounder Picture . Selecting the color bar (hue) and white level 4 Understanding Depth Settings . [. . . ] Weaker echoes are displayed with colors near the bottom of the scale, and stronger echoes are displayed with colors near the top. You can choose any one of nine palettes of colors to represent the echo strengths from weakest to strongest. · · · · Color bar #1 is the one most often used. Color bar #2 is similar but with fewer colors, to aid visibility under some conditions. Color bars # 3-8 are additional variations with different background colors. Color bar #9 uses only a single color, ranging from very dark to very bright. Selecting the color bar (hue) To select the color bar: 1. At the HUE AND WHITE LEVEL window, press the CURSOR PAD left or right to select the color bar desired, or use the KEYPAD to manually enter the number of the color bar. Page 32 491 Echo Sounder Operations Manual Hue and white level window 4. Press RETURN to go back to the ECHO screen. Setting the white level You can replace any single color in the color bar with white. On the HUE AND WHITE LEVEL window, press the CURSOR PAD up or down to select that color. To remove the white level and return to using all the colors on the color bar, press the CURSOR PAD down until the white level moves off the color bar. 491 Echo Sounder Operations Manual Page 33 Page 34 491 Echo Sounder Operations Manual 4Unde rstanding Depth Settings Viewing the seabed depth . 4-38 Thisdepth settings andhow to override thethe depth autochapter explains system's matic manually control range shown on the screen, and how to use the depth marker. 491 Echo Sounder Operations Manual Page 35 Viewing the seabed depth The seabed depth (the "bottom") is displayed in a black box at the left edge of the ECHO screen. You can change the size and location of the depth box on the ECHO screen. There are four available sizes: · · · · small medium large huge To resize the depth box or move it up or down: 1. The depth box can also be adjusted by pressing MORE, then pressing DATA. Viewing the depth marker You can use the depth marker to accurately measure the depth of an echo. To display the depth marker--a dashed horizontal line--and move this marker up or down, press the CURSOR PAD down. Attached to the depth marker line is a small black box, which displays the marker's exact depth. The depth marker also affects the display in Marker Zoom mode. Changing the depth settings You can adjust the shallowest and deepest echoes to be shown on the ECHO screen. In automatic mode, the echo sounder sets these values based on its current environment. However, Page 36 491 Echo Sounder Operations Manual you can manually override these auto values for your specific needs at any time. There are two depth settings: · · shift (how far below the surface the echo sounder picture starts) range (the depth covered by the echo sounder picture from the top of the screen to the bottom of the screen) Setting the picture's shift (starting depth) The shift setting adjusts the depth of the top edge of echoes pictured on the ECHO screen. You can "shift" the entire picture up and down to start at the surface of the water, or any other depth you choose. Press SHIFT. Shift window The SET SHIFT window shows a picture of the current shift settings (and range). [. . . ] Check the wiring of the data cable between the navigator and the 491. RED 1. If the transducer is open or shorted, replace it There's a hardware problem with the 491. Figure 10: Troubleshooting the echo sounder (957/958) Checking the transducer To provide the best possible performance with the 491 echo sounder, Northstar recommends the use of an Airmar 491 Echo Sounder Operations Manual Page 65 transducer. The models below can be purchased from Northstar. Table 3: Northstar-recommended transducers Manufacturer Airmar Airmar Airmar Model B260 B744V (w/3-wire speed) P66 Power 1 kW 600 W 600 W Northstar P/N TD1004 TD1005 TD1006 Airmar Technology Corporation may be reached at 35 Meadowbrook Drive, Milford, New Hampshire 03055-4613; phone 603/673-9570; fax 603/673-4624. NOTE: Detailed information on maintaining and troubleshooting a transducer is outside the scope of this manual. [. . . ]