NorthStar Navigation Fish Finder NorthStar 491 User Manual

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  
a unit of Brunswick New Technologies Marine Electronics  
30 Sudbury Road  
Service: 978/897-6600  
Sales: 800/628-4487  
Acton, Massachusetts 01720  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6
7
Marking fish as waypoints . . . . . . . . . . . . . . 53  
Understanding the alarms . . . . . . . . . . . . . . 56  
Setting the fish alarm . . . . . . . . . . . . . . . . . . 56  
Setting the bottom alarm . . . . . . . . . . . . . . . 58  
Setting the temperature alarm . . . . . . . . . . . 60  
8
Troubleshooting 491 Operations . . . . . . . . . . . . 63  
Troubleshooting the echo sounder . . . . . . . 64  
Checking the transducer . . . . . . . . . . . . . . . 65  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Download from Www.Somanuals.com. All Manuals Search And Download.  
1
Using this manual . . . . . . . . . . . . . . . . . . . . . . . . . 1-2  
Technical support . . . . . . . . . . . . . . . . . . . . . . . . . 1-4  
How echo sounding works . . . . . . . . . . . . . . . . . 1-5  
Powering the 491 on and off . . . . . . . . . . . . . . 1-7  
Setting up the 491 . . . . . . . . . . . . . . . . . . . . . . . . . 1-7  
This chapter introduces the Northstar 491 Operations  
Manual, explains how to contact Northstar for technical  
support and service, and describes the 491’s basic set-up and  
power on/off procedures.  
491 Echo Sounder Operations Manual  
Page 1  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Welcome to the Northstar 491  
Congratulations on your purchase of the Northstar 491 Echo  
Sounder. The 491 connects with a Northstar navigator and a  
third-party transducer to add echo sounding capability to the  
Northstar 957, 958, 961, and 962 navigators. See the Northstar  
491 Installation Manual (part number GM495) for  
You may be adding the 491 to your existing Northstar  
navigator for echo sounding, or you may have purchased your  
navigator complete with echo sounding. In either case, the 491  
should be installed and configured by a qualified marine  
technician.  
To get started right away, Section 2, ”Quick Start: Using the  
Echo Sounder,” starting on page 2-11.  
CAUTION!  
Proper installation and configuration of your Northstar  
491 is of utmost importance for accurate and effective  
performance under a variety of conditions. To get the  
best performance from your 491, Northstar strongly rec-  
ommends installation and set-up by a qualified marine  
technician. For installation procedures, see the Northstar  
491 Echo Sounder Installation Manual (Part Number  
GM495).  
Using this manual  
Chapter 1 introduces you to the 491 echo sounder and to this  
operations manual.  
Organization  
Chapter 2 gives you a quick-start introduction to get you  
started with echo sounding as soon as the 491 has been  
installed and configured.  
Chapter 3 tells how to adjust the echo sounder’s display—the  
gain, clutter, colors, etc.  
Page 2  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
Chapter 4 describes how to adjust the depth settings to choose  
what portion of the water under the vessel you’ll display.  
Chapter 5 explains other functions—the A-Scope, etc.  
Chapter 6 describes Northstar’s exclusive SoundTrac™ feature,  
for accessing past echoes and navigating back to their  
locations.  
Chapter 7 tells how to use the echo sounder’s alarms: the fish  
alarm, bottom alarm, and temperature alarm.  
At the back of the manual are a glossary and an appendix  
outlining the 491’s specifications.  
Specific conventions are used to provide a consistent way to  
recognize certain information, as follows:  
Conventions  
is the universal symbol used for caution and warning  
information that pertains to your personal safety or pre-  
vents damage to the 491. The CAUTION and WARNING  
boxes contain critical information—please read them!  
NOTE is the type style used for titles of reader notes. These  
notes contain valuable information purposely highlighted  
so that you don’t miss it while reading the main text.  
KEY is the type style used to refer to the menu keys on  
the display screen.  
DISPLAY TEXT is the type style representing text on the  
display screens.  
A bulleted list contains a series of related items or topics.  
A numbered list contains a series of steps in a procedure.  
491 Echo Sounder Operations Manual  
Page 3  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Technical support  
After you follow the instructions in this manual, if you need  
technical support or if you have any other questions, you can  
contact Northstar by email, fax, phone, or U.S. mail as follows:  
Table 1: Contacting Northstar  
Email:  
Service: [email protected]  
Fax:  
Service: 978/897-1595  
Sales: 978/897-7241  
Telephone:  
978/897-6600 or 800/628-4487  
U.S. mail:  
30 Sudbury Road  
Acton, MA 01720  
Web site:  
Northstar directly from this site)  
Your feedback is important and helps ensure that this manual  
is a valuable resource for all 491 users. Send your questions,  
comments, or suggestions about this manual to:  
Hearing from you  
Service and repair  
In case of an operating problem with your Northstar 491, you  
may contact your dealer or return the unit to the Northstar  
factory for diagnosis and repair. When describing an operating  
problem, be as complete and accurate as possible. Be sure to  
have the serial number available whenever contacting or  
corresponding with either your dealer or the Northstar factory.  
The 491’s serial number is located at the top of the unit. If you  
need help, feel free to call the Northstar Service Department at  
978-897-6600 between 9:00 a.m. and 5:00 p.m. weekdays,  
excluding major holidays.  
Page 4  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
To prevent delays, it is critical that you first obtain a Return  
Materials Authorization (RMA) number before returning your  
unit to the factory. If you purchased your 491 through a  
dealer, to get an RMA number, call the dealer with the serial  
number. The 491’s serial number is located at the top of the  
unit.  
The 491 should be shipped in a properly designed carton with  
packing material. Please reference the RMA number on the  
outside of the carton.  
Shipments to Northstar should be made to the following  
address:  
Northstar Technologies  
30 Sudbury Road  
Acton, MA 01720  
If you have overnight or second-day shipping requirements,  
please call the Northstar factory for turnaround time and  
freight costs before shipping your 491.  
How echo sounding works  
An echo sounder produces high-voltage electrical pulses that  
the transducer converts into sound waves (called “pings”). The  
sound waves are sent downward through the water. When a  
sound wave hits and reflects off an object, such as fish, debris,  
seaweed, or the seabed, the reflected sound wave (an “echo”)  
returns back to the transducer along an imaginary vertical line  
the water and seabed can be displayed and analyzed on the  
echo sounder screen. In essence, this system lets you see a  
real-time cross section of what’s happening underneath your  
vessel.  
Figure 1, ”957/958 echo sounder system components,” below,  
and Figure 2, ”961/962 echo sounder system components,”  
below, show how the 491 connects to these navigators to  
enable echo sounding functions.  
491 Echo Sounder Operations Manual  
Page 5  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
GPS  
antenna  
33-foot cable  
(part of transducer)  
491  
module  
957/958/6000i  
Navigator  
10-foot cable  
Ship's  
Power  
Transducer  
(Northstar-supplied)  
10-foot cable  
(Northstar-supplied)  
Figure 1: 957/958 echo sounder system components  
GPS  
antenna  
Control  
Head  
33-foot cable  
(part of transducer)  
491  
module  
961/962  
Processor  
10-foot cable  
Ship's  
Power  
Transducer  
(Northstar-supplied)  
10-foot cable  
(Northstar-supplied)  
Figure 2: 961/962 echo sounder system components  
Page 6  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
Powering the 491 on and off  
As part of its power-up sequence, the navigator automatically  
activates the 491.  
The 491 is automatically shut off by the navigator when you  
press and hold PWR until the screen goes dark.  
Setting up the 491  
Your 491 should be installed by a qualified marine technician.  
Your satisfaction with the system’s performance will be greatly  
influenced by the practical knowledge and experience of the  
installer. Unlike GPS or other marine electronics systems, echo  
sounder installation is as much an art as a science.  
The installation procedure includes setting up the following  
options:  
the transducer’s depth  
the speed and temperature  
the calibration for the speed sensor  
the calibration for the temperature sensor  
the gain calibration for the transducer  
You may wish to change the following options from time to  
time to match your personal preferences:  
depth units (feet, meters, or fathoms) on the screen  
temperature units (Celsius or Fahrenheit) on the screen  
temperature scale (lowest and highest) on the screen  
(961/962 only) automatic saving of *FISH##* or  
*THERM##* waypoints when the 491 detects the presence  
of fish or a certain water temperature that you’ve set  
Before starting, you should double-check that the 961/962’s  
Port 3 is set to the 490 option:  
Using 491 with the  
961/962  
1. Press STAR until you reach the SERVICE MENU screen.  
2. Press PORT SETUP.  
3. Press PORT 3.  
491 Echo Sounder Operations Manual  
Page 7  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
4. Check that the FORMAT option is set to “490.” If not, set it  
now.  
Before starting, you should double-check that the navigator’s  
AUX port is set to the Sounder option:  
Using the 491 with  
the 957/958  
1. Press STAR until you reach the OPTIONS/SERVICE INFO  
screen.  
2. Press the PORT SETUP OPTIONS key.  
3. Check that the AUX PORT option is set to “Sounder.” If  
not, set it now.  
Page 8  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Figure 3:  
STAR key  
Auto  
Picture  
ECHO  
SCREEN  
Frequency  
Zoom  
Depth  
More  
Depth settings  
Picture settings  
Gain  
Shift  
Range  
Clutter  
Noise Limiter  
Hue  
Signal level  
Return  
More settings  
Alarms  
Advance Speed  
Snapshot  
A-Scope  
Data  
Bottom box  
Return  
Return  
Alarm settings  
Data on-screen  
Snapshot  
Bottom box  
Temp box  
Temp graph  
Speed  
Display  
Rename  
Fish alarm  
Bottom alarm  
Temp alarm  
Archive  
Erase  
Return  
Return  
Return  
Figure 4: 961/962 echo sounder menu structure  
491 Echo Sounder Operations Manual  
Page 9  
Download from Www.Somanuals.com. All Manuals Search And Download.  
STAR key  
Auto  
Picture  
ECHO  
SCREEN  
Frequency  
Zoom  
Depth  
More  
Depth settings  
Picture settings  
Gain  
Shift  
Range  
Clutter  
Noise Limiter  
Hue  
Signal level  
Return  
More settings  
Alarms  
Advance Speed  
Video  
Bottom box  
Return  
A-Scope  
Data  
Return  
Alarm settings  
Data on-screen  
Video setup  
Temp box  
Temp graph  
Bottom box  
Speed  
Video on  
Fish alarm  
Bottom alarm  
Temp alarm  
Return  
Return  
Return  
Figure 5: 957/958 echo sounder menu structure  
Page 10  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
2
Introducing the displayed information . . . . 2-15  
Using automatic mode . . . . . . . . . . . . . . . . . . . . 2-16  
Changing the frequency of echoes . . . . . . . . 2-17  
Zooming in and out . . . . . . . . . . . . . . . . . . . . . . . 2-19  
Setup functions . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22  
This chapter shows you how to start using the echo sounder,  
and explains several of the echo sounder’s important features.  
491 Echo Sounder Operations Manual  
Page 11  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Displaying the echo sounder’s picture  
Once the navigator has been configured to operate with the  
491, you’re ready to start viewing echo sounding data.  
To see the echo sounding screen at any time, press STAR from  
any screen. You’ll see live echoes moving across the screen.  
Depth  
marker  
and  
Echo data  
Depth Scale  
indicator  
Water  
temperature  
box  
Color  
bar  
Water  
temperature  
scale  
Frequency  
selection and  
indicator  
Depth  
box  
Navigation  
information  
Lat/lon of  
vessel  
Dist/brg  
to waypoint  
Steering indicator  
Speed, course, and speed  
through the water  
Figure 6: Illustrated ECHO screen  
You can also review old echoes using Northstar’s SoundTrac  
feature. To activate SoundTrac, press the CURSOR PAD left or  
right on the ECHO screen. The position marker appears  
(controlled by the CURSOR PAD), and movement of echoes to  
the left stops. The data boxes at the bottom of the screen turn  
white and refer to the position marker rather than to your  
current position. Press the green LIVE DATA key to return to  
Page 12  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
real-time echoes. For details, see “Reviewing past echoes using  
SoundTrac” starting on page 51.  
Depth  
marker  
and  
Echo data  
Depth Scale  
indicator  
Water  
temperature  
box  
Color  
bar  
Position  
marker  
and  
Water  
temperature  
scale  
indicator  
Depth  
box  
Lat/lon of  
position  
marker  
Dist/brg to  
position  
marker  
Steering indicator  
Speed, course, and speed  
through the water  
Figure 7: Illustrated SOUNDTRAC screen  
NOTES:  
All of the alarm messages always appear on all of the echo  
sounder’s screens. You won’t miss any alarms while displaying  
echo sounding data, and you never have to press any keys to view  
the current alarms (although you must press STAR to clear alarms  
that don’t automatically clear).  
The SAVE and MOB functions always work normally. Moreover,  
on the 961/962, whenever you press either of these keys, the corre-  
sponding *SAVE##* or *MOB##* waypoints will be displayed  
automatically on the echo sounder’s picture, as well as on the  
CHART screen (after you press CHART).  
491 Echo Sounder Operations Manual  
Page 13  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Using demo mode  
The echo sounder can be operated in “demo mode” for  
training and familiarization. Simulated echo data generated by  
the 491 will be displayed.  
To enter demo mode:  
1. Press STAR several times to display the ECHO SOUNDER  
SETUP screen.  
2. Press the CURSOR PAD down to select demo mode, then  
press EDIT.  
3. Press the CURSOR PAD left or right to highlight “ON,”  
then press ACCEPT.  
While in demo mode, the word “Demo” appears in the  
upper right corner of the ECHO screen.  
To leave demo mode, repeat this procedure, selecting “OFF”  
instead of “ON.”  
You can overlay a smaller version of the echo screen onto the  
CHART screen.  
Displaying echo  
sounder data on the  
CHART screen  
To overlay the echo screen:  
For the 961/962  
1. Press CHART to display the CHART screen, then press  
OVERLAY.  
2. At the CHART OVERLAY SELECTION window, press  
SHOW 490.  
Both chart views A and B will display live echo sounder  
data on the right-hand side of the screen.  
3. To remove echo sounder data, press HIDE 490 on the  
CHART OVERLAY screen.  
To overlay the echo screen:  
For the 957/958  
1. Press CHART to display the CHART screen, then press  
SOUNDER. The CHART screen will display live echo  
sounder data on the right-hand side of the screen.  
Page 14  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Introducing the displayed information  
The following information can be displayed on the ECHO  
screen.  
echo sounder data  
Echo sounding  
echo sounder frequency in use (50 or 200 kHz or both)  
A-scope  
automatic mode indicators (fishing or cruising)  
manual operation indicator  
echo colors in use (the “color bar” at the far left)  
SoundTrac’s position marker for scrolling to old echoes  
water-depth digital display (on the left side of the screen)  
depth scale (on the right side)  
Depth and  
temperature  
depth marker (press the CURSOR PAD to scroll the  
marker down)  
water-temperature digital display (if temperature sensor is  
connected; can be turned off)  
water temperature graph (if temperature sensor is con-  
nected; can be turned off)  
vessel’s current lat/lon (on the SOUNDTRAC screen, this  
lat/lon indicates the position marker’s location)  
Navigation  
Status tabs  
vessel’s SOG and COG  
active waypoint, if any, and graphic steering indicator  
vessel’s Speed Through the Water (if speed sensor is con-  
nected; can be turned off)  
To help you use the echo sounder’s functions, many of the  
key’s labels on the right edge of the screen show the status of  
that key’s function in a tab directly under the label.  
491 Echo Sounder Operations Manual  
Page 15  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Using automatic mode  
To operate the echo sounder automatically, just press AUTO.  
All of the 491’s adjustments will be set to produce a useful  
picture under most conditions. When you’re too busy to  
optimize the settings manually, the echo sounder can  
automatically set the optimal gain, clutter, and range settings,  
to show an excellent picture, from the surface to the bottom.  
When you select auto, the range setting may change from time to  
time to keep the seabed in view as the water depth changes.  
It is recommended that the 491 be operated automatically  
whenever possible. The 491 can reliably detect the seabed  
depth only when it controls the gain and clutter settings.  
You can always press AUTO on the ECHO screen to remove  
any manual settings you’ve made and return to the standard  
automatic configuration.  
Automatic mode has two variations: autocruising and  
autofishing.  
Cruising or fishing  
autocruising optimizes the gain and clutter for tracking  
the bottom, with less emphasis on any fish in the water  
autofishing optimizes the gain and clutter for searching  
for fish  
Press AUTO to switch between autocruising and autofishing.  
The colored tab below the menu key indicates whether the  
unit is optimized for cruising or fishing.  
Colored status tabs just below the AUTO and PICTURE keys  
are green when the echo sounder is operating fully  
automatically. They turn yellow when any of the settings has  
been set manually. (In some cases, the picture tab may be  
yellow while the auto tab is still green, if the Noise Limiter is  
turned on, for example.)  
The status tabs  
Page 16  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
You can always manually change any of the echo sounder’s  
settings: the gain, clutter, noise limiter, shift, and range.  
Manually  
overriding  
automatic mode  
Changing the appearance of the picture (colors, gain, clutter,  
and the noise limiter) is described in Chapter 3.  
Setting the range and shift is described in Chapter 6.  
Changing the frequency of echoes  
The 491 uses two transducer frequencies: 50 kHz and 200  
kHz. The advantages and disadvantages of each frequency are  
shown below.  
Table 2: 50 kHz vs. 200 kHz  
50 kHz  
200 kHz  
Longer wavelength goes deeper,  
but with somewhat lower resolu-  
tion.  
Shorter wavelength provides a  
sharper picture, but can’t go as  
deep.  
Less resolution is better at finding  
big fish, but may miss the bait  
fish.  
Finer resolution is better at find-  
ing small fish (baitfish) and subtle  
bottom details.  
Wider beam is good for seeing  
Narrower beam is very focused.  
fish not directly beneath the boat. Reduces the influence of a rough  
sea.  
You can choose from four settings for the transducer  
frequency:  
50 kHz displayed on a full screen  
200 kHz displayed on a full screen  
50 kHz on the left half of the screen, and 200 on the right  
200 kHz on the left half of the screen, and 50 on the right  
There are two reasons why you might want to operate with  
your preferred frequency on the right side of the screen:  
the zoom function magnifies the frequency on the right  
side  
491 Echo Sounder Operations Manual  
Page 17  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
when adjusting the picture, you can see the effect of  
changes on the right side  
50 kHz echoes  
200 kHz echoes  
Adjusts the frequency  
of the data displayed  
(currently showing dual  
frequency on a split  
screen, with 50 kHz to  
the left and 200 kHz to  
the right)  
Figure 8: ECHO screen with both frequencies displayed  
To change the display frequency:  
1. On the ECHO screen, press FREQUENCY until you  
display the desired frequency or frequencies.  
The frequencies in use are shown pictorially on the tab  
just below the FREQUENCY key.  
When you change the frequency, echoes already on the screen  
don’t change, they just move off the screen as they are  
replaced by echoes at the new frequency.  
A dual-frequency screen is split into two halves separated by a  
gray vertical line in the center.  
Page 18  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
When using the zoom feature (which also splits the screen  
into halves), both sides of the screen always display the same  
frequency.  
Zooming in and out  
On the ECHO screen, the echo sounder’s zoom feature  
expands a portion of the echoes. You can examine closely any  
part of the water column, to determine the composition of the  
bottom or look at the echoes of fish, rocks, or wrecks. When  
fishing, the zoom function is useful for showing a detailed  
view of any echoes below the vessel.  
Press IN to zoom in and increase the magnification of the  
echoes you see below the top edge of the marker. Press OUT to  
zoom out and increase the amount of water seen.  
Choosing the zoom  
scale  
You can choose from any of six depth scales for the magnified  
echoes. These scales cover the same depths regardless of the  
scale of the original echoes.  
The available scales are: 15’, 30’, 60’, 120’, 240’ and 480’ when  
using units of “feet.” Similar scales are available for the other  
depth units.  
NOTE:  
When zoom is in use, only a single frequency is displayed.  
Unzoomed echoes are on the right, and the same frequency is  
shown magnified on the left. Whatever frequency was previously  
shown on the left is replaced by a magnified view of the right side.  
NOTE:  
You cannot zoom out to a scale that shows more water than the  
original picture. For example, if the original picture is set to a scale  
of 50’, the only zoom scales available will be 15’ and 30’.  
Press ZOOM on the ECHO screen to cycle through the four  
zoom modes (and choose the one you want):  
Choosing a zoom  
mode  
bottom zoom  
bottom lock  
bottom lock/center  
491 Echo Sounder Operations Manual  
Page 19  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
marker zoom  
The original unzoomed echoes are on the right side, and the  
magnified area is shown on the left side of the screen.  
A tab below the ZOOM key shows which zoom mode is in use.  
When you select bottom zoom, the contour of the bottom is  
magnified, clearly displaying canyon edges and echoes near  
the seabed. The 491 automatically locates the seabed and  
displays it on the lower left side of the screen (normal echoes  
are displayed on the right side).  
Using bottom zoom  
If the seabed moves out of the lower half of the screen (for  
example, if you travel into deeper water), the 491  
automatically repositions the bottom back into the lower half.  
You’ll see the zoomed image jump up or down from time to  
time, as the 491 keeps the seabed displayed on the screen.  
When you select bottom lock zoom, the magnified sea bottom  
is flattened out and displayed on the left side of the screen at  
the lower edge. You can see any fish that are swimming near  
the bottom.  
Using bottom lock  
zoom  
Page 20  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
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 bottom lock/  
center 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  
Using marker zoom  
491 Echo Sounder Operations Manual  
Page 21  
Download from Www.Somanuals.com. All Manuals Search And Download.  
the magnified area up or down, press the CURSOR PAD to  
move the depth marker.  
You can return to the normal unzoomed display just by  
pressing and holding ZOOM for more than one second, or by  
pressing ZOOM repeatedly until you have cycled through all  
the zoom modes.  
Leaving zoom mode  
Setup functions  
Several setup functions are available to configure the echo  
sounder to your preferences.  
CAUTION:  
Be careful not to change any of the functions that are not described  
here unless you first read about them and understand their functions  
in the Northstar 491 Installation Manual.  
To access the ECHO SOUNDER SETUP screen, press STAR  
several times until “Echo Sounder” is highlighted at the top of  
the screen.  
Accessing the setup  
screen  
Page 22  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
961/962 echo sounder setup screen  
957/958 echo sounder setup screen  
When changing the numerical value of the echo sounder’s  
settings, you can either press the CURSOR PAD to increase or  
decrease the value, or use the KEYPAD to manually type in  
the desired value.  
Entering numerical  
values  
491 Echo Sounder Operations Manual  
Page 23  
Download from Www.Somanuals.com. All Manuals Search And Download.  
This option specifies how far below the surface of the water  
the transducer is mounted. The number is added to all depths  
measured by the 491 so they will refer to depth from the  
surface, not from the transducer. This value should have been  
set correctly during installation and should not be changed.  
Transducer depth  
You can change the depth units to feet, meters, or fathoms:  
Changing the depth  
units  
1. Press the CURSOR PAD up or down to highlight the  
DEPTH UNITS option.  
2. Press EDIT.  
3. Press the CURSOR PAD left or right to highlight the  
desired units. Press ACCEPT.  
You can change the highest and lowest water temperatures  
that will be displayed on the temperature graph:  
Changing the  
temperature  
graph’s units and  
scale  
1. Press the CURSOR PAD up or down to highlight the line  
containing the temperature scale.  
2. Press EDIT.  
This option only  
3. Press the CURSOR PAD left or right to highlight °C or °F,  
appears on the screen  
if a temperature sensor  
is connected.  
as desired, then press ACCEPT.  
4. To change the endpoints of the scale, press EDIT DATA.  
5. Enter the lower temperature limit using the KEYPAD.  
6. Press the CURSOR PAD to the right to highlight the  
upper limit and enter its value on the KEYPAD.  
7. Press ACCEPT.  
In the 961/962, the echo sounder can be set to store waypoints  
automatically at the following location:  
Number of special  
waypoints  
where fish are detected by the fish alarm  
where the water temperature passes preset limits  
where fish or other echoes are marked by the user  
These waypoints are automatically given names such as  
*FISH##*, where ## is a waypoint sequence number that  
increases to a preset limit. When this limit is reached, the  
Page 24  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
sequence number restarts at 00, and the oldest waypoints with  
this same name will be overwritten (unless they have been  
renamed).  
To turn this feature on or off, or to change the maximum  
number of each of these waypoints:  
1. Press the CURSOR PAD up or down to highlight the  
waypoint type you want to change:  
The line “*Fish##*:” controls fish waypoints  
The line “*Therm##*:” controls temperature waypoints  
The line “Mark Wpts:” controls waypoints marked by the user  
2. Press EDIT.  
3. Press the CURSOR PAD left or right to highlight the  
desired number of waypoints to be saved.  
4. Press ACCEPT.  
These functions are set during installation. The calibrations  
should not be changed unless they are known to need  
adjustment.  
Speed and  
temperature sensor  
setup  
From the ECHO SOUNDER SETUP screen, press SPEED/TEMP  
to access the SENSOR SETUP screen.  
961/962 sensor setup screen  
491 Echo Sounder Operations Manual  
Page 25  
Download from Www.Somanuals.com. All Manuals Search And Download.  
957958/ sensor setup screen  
To simplify operation, the “sensor installed” options can be set  
to “No” to remove all references to temperature and speed  
from all the screens.  
Highlight the appropriate line and press EDIT to change an  
option.  
Speed calibration is entered as a percentage from –99% to  
+99% to make the speed read lower or higher than the  
uncalibrated value.  
NOTE:  
You must enable the speed setting under the Data menu on the  
ECHO SOUNDER screen; see ”Setting the ECHO screen data”  
starting on page 5-44..  
Temperature is calibrated by entering the temperature error as  
a number of degrees from –99 to +99. This offset is added to  
the uncalibrated temperatures before they are displayed or  
graphed.  
Page 26  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
3
Adjusting the gain (strong echoes) . . . . . . . . 3-28  
Adjusting the clutter (weak echoes) . . . . . . . 3-29  
Adjusting the signal level (weak echoes) . . 3-30  
Suppressing interference (the noise limiter) 3-31  
Selecting the color bar (hue) and white level 3-32  
This chapter explains the different ways you can adjust the  
echo sounder’s picture, including gain, clutter, the noise  
limiter, white level, and signal level.  
491 Echo Sounder Operations Manual  
Page 27  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
The picture menu  
You can adjust the appearance of echoes in five different ways:  
gain (for high intensity echoes)  
clutter (for low intensity echoes)  
noise limiter (for interference)  
hue (to choose colors and white level)  
signal level (to remove weak echoes)  
Gain and clutter changes are applied only to new echoes as  
they appear on the right side of the screen—earlier echoes are  
not affected.  
NOTE:  
When you override the gain’s automatic settings, the tabs on the  
PICTURE key and AUTO key change from green to yellow, indi-  
cating the system is no longer in automatic mode. When you turn  
the noise limiter on, only the PICTURE key tab changes from green  
to yellow. Changing the hue or adjusting the signal level has no  
effect on the operating mode (the tabs stay green).  
Adjusting the gain (strong echoes)  
The gain setting selects the echo strengths that will be  
displayed using the top color in the color bar (the strongest  
echoes). Any echoes stronger than this selection will use the  
same color and no detail can be distinguished. The gain is  
usually set so that seabed echoes are displayed in brown, the  
strongest level.  
The gain can be also be set automatically by pressing the  
AUTO key. This will provide an excellent picture under most  
conditions, and will allow the 491 to reliably detect the seabed  
depth.  
Gain is normally adjusted in conjunction with clutter, as  
described on the next page, to maximize its effectiveness.  
To adjust the gain:  
1. On the ECHO screen, press PICTURE.  
2. On the PICTURE screen, press GAIN.  
Page 28  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
3. At the GAIN window, press the CURSOR PAD left or right  
to adjust the gain, or use the KEYPAD to manually enter  
the desired gain value. The available settings range from  
zero (minimum) to 75 (maximum).  
Gain window  
The window shows the effect of adjusting the gain. The  
fish symbols near the bottom of the window represent  
various echo strengths, and the expanding and  
contracting color bar above shows the colors that will be  
used to display these echoes. As you adjust the gain to  
obtain the best looking picture, also watch the real echoes  
on the right side of the screen .  
4. Press RETURN to go back to the ECHO screen.  
When you adjust the gain, the color of the AUTO and  
PICTURE key tabs changes from green to yellow, since  
the echo sounder is no longer in automatic mode. Also, a  
yellow tab appears under the DEPTH key, indicating that  
the range setting is no longer automatically controlled and  
that the 491 may not always identify the bottom reliably.  
Adjusting the clutter (weak echoes)  
The clutter setting selects the echo strength that will be  
displayed using the bottom colors of the color bar (the weaker  
echoes). Any echoes weaker than this selection will not be  
491 Echo Sounder Operations Manual  
Page 29  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
displayed. If you select 5, for example, all weak and moderate  
echoes will be displayed using the background color (just as if  
they weren’t there). You might choose this setting to eliminate  
high levels of background noise and echoes from turbulence  
or plankton. A setting of 0 allows all echoes to be displayed.  
To adjust the clutter:  
1. At the ECHO screen, press PICTURE.  
2. At the PICTURE screen, press CLUTTER.  
3. Press the CURSOR PAD left or right to adjust the clutter,  
or use the KEYPAD to manually enter the desired clutter  
value. The available settings range from zero (minimum)  
to nine (maximum).  
Clutter window  
4. Press RETURN to go back to the ECHO screen.  
When you adjust the clutter, the color of the AUTO and  
PICTURE key tabs changes from green to yellow, since  
the echo sounder is no longer in fully automatic mode.  
Adjusting the signal level (weak echoes)  
As with the CLUTTER key, the SIGNAL LEVEL key controls  
the appearance of low level noise in the picture. Whereas  
clutter compresses or expands the available colors to fit the  
Page 30  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
desired signal range, Signal Level completely removes the  
weaker colors and their echoes.  
To adjust the signal level:  
1. On the ECHO screen, press PICTURE.  
2. On the PICTURE screen, press SIGNAL LEVEL.  
3. At the SIGNAL LEVEL window, press the CURSOR PAD  
up or down to remove the weaker color levels from the  
picture, or use the KEYPAD to manually enter the desired  
signal level.  
The available settings range from 1 (minimum) to 5 (max-  
imum). For example, if you select a signal level of 3, echo  
strengths of 0 through 3 are all displayed using the same  
color.  
4. Press RETURN to go back to the ECHO screen.  
Suppressing interference (the noise limiter)  
The noise limiter reduces the adverse effects of interference  
from other nearby echo sounders or electronic devices.  
however, the noise limiter may cause some very weak echoes  
to be made smaller or entirely eliminated, since it removes any  
echoes that aren’t sustained for at least two pings.  
To turn on the noise limiter:  
1. At the ECHO screen, press PICTURE.  
2. At the PICTURE screen, press NOISE LIMITER.  
3. At the NOISE LIMITER window, press the CURSOR PAD  
up to turn the noise limiter on (or press NOISE LIMITER  
again).  
4. Press the RETURN key to go back to the ECHO screen.  
Turning the noise limiter on changes a portion of the  
PICTURE key tab from green to yellow, as a reminder.  
491 Echo Sounder Operations Manual  
Page 31  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Selecting the color bar (hue) and white level  
The color bar displayed at the extreme left of the ECHO screen  
Understanding the  
color bar  
shows the range of colors used to display different echo  
strengths. 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 visibil-  
ity 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.  
To select the color bar:  
Selecting the color  
bar (hue)  
1. On the ECHO screen, press PICTURE.  
2. Press HUE.  
3. 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  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Hue and white level window  
4. Press RETURN to go back to the ECHO screen.  
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.  
Setting the white  
level  
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  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Page 34  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4
Viewing the seabed depth . . . . . . . . . . . . . . . . 4-36  
Viewing the depth marker . . . . . . . . . . . . . . . . 4-36  
Changing the depth settings . . . . . . . . . . . . . . 4-36  
Setting the picture’s shift (starting depth) . . 4-37  
Setting the picture’s range . . . . . . . . . . . . . . . . 4-38  
This chapter explains how to override the system’s auto-  
matic depth settings and manually control the depth range  
shown on the screen, and how to use the depth marker.  
491 Echo Sounder Operations Manual  
Page 35  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
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. Its size on the SOUNDTRAC screen is always  
small.  
There are four available sizes:  
small  
medium  
large  
huge  
To resize the depth box or move it up or down:  
1. At the ECHO screen, press DEPTH.  
2. To cycle through the size choices, repeatedly press  
BOTTOM BOX. To move the box up and down, press the  
CURSOR PAD.  
3. Press RETURN to go back to the ECHO screen.  
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  
Download from Www.Somanuals.com. All Manuals Search And Download.  
     
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 pic-  
ture up and down to start at the surface of the water, or any  
other depth you choose.  
To shift the picture:  
1. At the ECHO screen, press DEPTH.  
2. Press SHIFT.  
Shift window  
The SET SHIFT window shows a picture of the current  
shift settings (and range). The large white number in the  
black box shows the current shift value. A sliding vertical  
bar shows the portion of the water that the echo sounder  
displays on the screen, based on the shift and range set-  
tings.  
491 Echo Sounder Operations Manual  
Page 37  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
In the large rectangle on the right, the blue area at the top  
(with waves) represents the surface of the water, and the  
brown area below represents the seabed.  
The number at the bottom is the depth of the picture, and  
the seabed depth is also labelled.  
The smaller rectangle inside the larger one represents the  
echo sounder’s picture. As you move the shift (and range)  
settings, this rectangle adjusts to show what you will see  
on the echo screen.  
A horizontal black arrow points to the value that this win-  
dow adjusts: the depth at which the echo sounder picture  
starts, relative to the surface of the water.  
3. Press the CURSOR PAD up or down to shift the picture,  
or use the KEYPAD to enter the digits of the desired  
depth. If you type the number on the keypad, wait a  
moment for the system to enter the number.  
4. Press RETURN to go back to the ECHO screen.  
Adjusting shift changes the AUTO and DEPTH key tabs  
from green to yellow, since the echo sounder is no longer  
in automatic mode.  
Setting the picture’s range  
The range setting adjusts the overall depth covered by the  
echo sounder picture, from the top of its display to the bottom.  
The range can be set automatically (by pressing AUTO), or  
manually on the SET RANGE window.  
To set the range:  
1. At the ECHO screen, press DEPTH.  
2. Press RANGE.  
Page 38  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Range window  
The vertical black arrow in the SET RANGE window ind-  
cates the values that this window adjusts: the range of the  
echo sounder picture, relative to the depth of the water.  
The white number in the black box indicates the current  
range setting.  
3. Press the CURSOR PAD up or down to adjust the range,  
or use the KEYPAD to manually enter the desired depth.  
4. Press RETURN to go back to the ECHO screen.  
Adjusting the range changes the AUTO and DEPTH sta-  
tus tab from green to yellow, since the echo sounder is no  
longer in fully automatic mode.  
491 Echo Sounder Operations Manual  
Page 39  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Page 40  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
5
Changing the advance speed . . . . . . . . . . . . . 5-42  
Displaying the A-scope . . . . . . . . . . . . . . . . . . . 5-43  
Setting the ECHO screen data . . . . . . . . . . . . . 5-44  
Introducing snapshots . . . . . . . . . . . . . . . . . . . . 5-46  
Setting up the video image overlay . . . . . . . 5-49  
This chapter describes all of the functions of the MORE key,  
except for the alarms, which are covered in Chapter 7.  
491 Echo Sounder Operations Manual  
Page 41  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Using the MORE key  
Pressing the MORE key accesses the following functions:  
alarms (described in Chapter 7)  
advance speed  
A-scope  
data (numeric and graphic information on the ECHO  
screen)  
snapshots (961/962 only)  
video overlay setup (957/958 only)  
When the menu function is in use in the 961/962, the ECHO  
screen moves every half second, giving the picture a less than  
smooth appearance. Press RETURN to go back to the main  
screen for a normal smooth appearance.  
Changing the advance speed  
Advance speed refers to the speed at which the vertical scan  
lines move from right to left across the ECHO screen. There  
are five advance speeds (plus the STOP setting, which freezes  
the advance of all data):  
2/1 - two identical lines of data are displayed for every  
ping  
1/1 - one line of data is displayed for every ping  
1/2 - one line of data is displayed for every two pings  
1/4 - one line of data is displayed for every four pings  
1/8 - one line of data is displayed for every eight pings  
For speeds 1/2, 1/4, and 1/8, each displayed line of data is  
averaged over 2, 4, or 8 pings.  
To set the advance speed:  
1. At the ECHO screen, press MORE, then press ADVANCE  
SPD.  
2. At the SET ADVANCE SPEED window, keep pressing the  
ADVANCE SPD key to select the desired advance speed.  
3. Press RETURN to go back to the ECHO screen.  
Page 42  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
The A-Scope shows every ping received, even when the  
advance speed setting causes pings to be averaged before  
display  
Displaying the A-scope  
The echo sounder’s A-scope lets you look closely at present or  
past echoes by horizontally magnifying the echo from each  
ping.  
To display the A-scope:  
1. Press MORE.  
2. Press A-SCOPE to turn the A-Scope on or off.  
A-scope on single-frequency echo screen  
The A-scope appears on the far right-hand side of the  
screen, magnifying the water column designated by the  
position marker.  
491 Echo Sounder Operations Manual  
Page 43  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
If you’re displaying both 50 and 200 kHz echoes, the A-scope  
magnifies echoes from the frequency shown on the right side  
of the screen.  
Using the A-scope  
with dual  
frequencies  
A-scope on dual-frequency echo screen  
If you’re in zoom mode, the A-scope magnifies the unzoomed  
echoes on the right side of the screen.  
Using the A-scope  
with zoom mode  
Setting the ECHO screen data  
Screen data refers to numeric and graphic information  
displayed on top of the echoes, including bottom depth, water  
temperature, and speed through the water (STW).  
To access these functions, press MORE, and then DATA.  
Page 44  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Echo screen data selections  
Press BOTTOM BOX to set the size and location of the box  
displaying the bottom depth (white numbers on a black  
background).  
Bottom depth box  
Temperature box  
Press this key again to cycle through the available sizes: small,  
medium, large, and huge.  
Press the CURSOR PAD up and down to set the position of the  
box at the left edge of the screen.  
Press TEMP BOX key to set the size and location of the box  
displaying the water temperature (white numbers on a black  
background).  
This key won’t appear  
unless a temperature  
sensor is installed and  
configured.  
Press this key again to cycle through the available sizes: off,  
small, medium, large, and huge.  
Press the CURSOR PAD up and down to set the position of the  
box at the left edge of the screen.  
491 Echo Sounder Operations Manual  
Page 45  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Press TEMP GRAPH to turn the temperature graph on or off.  
Temperature graph  
The temperature graph displays an orange temperature scale  
at the left of the screen, and an orange line tracing out the  
varying water temperature measurements, superimposed on  
the echoes.  
This key won’t appear  
unless a temperature  
sensor is installed and  
configured.  
Press SPEED to turn the Speed Through the Water display on  
or off. STW is displayed on the bottom right corner of the  
screen.  
Speed through the  
water  
This key won’t appear  
unless a speed sensor  
is installed and  
configured.  
Introducing snapshots  
A snapshot is a picture of the 961/962’s echo sounder screen.  
You can store up to 10 different snapshots of echo sounder  
screens for later review. These can be stored on floppy disk  
(one snapshot per floppy) or zip disk for permanent archiving.  
The snapshot feature is not available in the 957/958 or 6000i.  
To take a snapshot, press MORE and then SNAPSHOT. The  
echo sounder screen will be recorded at that instant.  
Taking and storing  
a snapshot  
To store the snapshot, you must save the snapshot in one of  
the ten available storage slots. Choose a slot by pressing the  
CURSOR PAD up or down to highlight the desired slot, then  
press SAVE to store the snapshot.  
Page 46  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Snapshot screen (961/962 only)  
To rename a stored snapshot, from the SNAPSHOT screen,  
press the CURSOR PAD to highlight the desired slot, and press  
RENAME. Use the KEYPAD to enter a new name and press  
ACCEPT.  
To display a stored snapshot, from the SNAPSHOT screen,  
press the CURSOR PAD to highlight the desired slot, and press  
DISPLAY. When finished, press RETURN.  
To erase a snapshot from a slot, from the SNAPSHOT screen,  
press the CURSOR PAD to highlight the desired slot, and press  
ERASE. You’ll be asked to confirm erasure by pressing YES.  
The slot will be erased to make room for a new snapshot.  
If your 961/962 has a floppy disk drive installed, you can save  
one snapshot on each disk.  
Archiving and  
restoring a  
snapshot with a  
floppy disk  
To save a stored snapshot onto a floppy disk, from the  
SNAPSHOT screen, press the CURSOR PAD to highlight the  
desired slot, and press ARCHIVE. Insert a floppy disk and press  
OK. Any old data on the disk will be erased!  
To restore a snapshot from a floppy disk to any empty slot,  
from the SNAPSHOT screen, press the CURSOR PAD to  
highlight the desired empty slot, and press RESTORE. Insert  
the floppy disk and press OK.  
491 Echo Sounder Operations Manual  
Page 47  
Download from Www.Somanuals.com. All Manuals Search And Download.  
If your 961/962 has a zip drive installed, you can save up to 10  
snapshots on each disk.  
Archiving and  
restoring snapshots  
with a Zip disk  
To save a stored snapshot onto a zip disk, from the SNAPSHOT  
screen, press the CURSOR PAD to highlight the desired slot,  
and press ARCHIVE. A new screen appears displaying the 10  
slots available on the zip disk.  
Archiving snapshots screen (961/962 only)  
Press the CURSOR PAD to select an empty slot on the disk,  
and press OK. The snapshot will be written to that slot on the  
zip disk.  
To restore a snapshot from a zip disk to any empty slot, from  
the SNAPSHOT screen, press the CURSOR PAD to highlight  
the desired empty slot, and press RESTORE. A new screen  
appears displaying the 10 slots on the zip disk. Use the  
CURSOR PAD to select the slot containing the snapshot you  
want to restore, and press OK.  
Page 48  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Setting up the video image overlay  
If you’ve connected the 957/958 to an NTSC-compatible  
device, you can display the image on the echo sounder screen.  
To display the video image on the ECHO SOUNDER screen,  
first press MORE, then press VIDEO.  
To change the transparency of the image while you’re  
displaying the ECHO SOUNDER screen, go to a different  
screen, press the navigator’s IN or OUT keys, then return to the  
ECHO SOUNDER screen.  
To change the size and placement of the image on the ECHO  
SOUNDER screen, press the STAR key to display the  
navigator’s VIDEO SETUP screen, then follow the instructions  
on the screen.  
491 Echo Sounder Operations Manual  
Page 49  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Page 50  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
6
Viewing past echoes using SoundTrac . . . . 6-52  
Marking fish as waypoints . . . . . . . . . . . . . . . . 6-53  
Navigating to a past echo position . . . . . . . . 6-53  
This chapter describes how to use SoundTrac to view past  
echoes, and how to navigate to any past echo positions.  
491 Echo Sounder Operations Manual  
Page 51  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Viewing past echoes using SoundTrac  
On the SOUNDTRAC screen, you can use Northstar’s exclusive  
SoundTrac feature to look back and examine past echo data.  
To enable SoundTrac, at the ECHO screen, press the CURSOR  
PAD to the left. A dashed vertical line—called the position  
marker—is now displayed.  
Echoes from at least  
the past three minutes  
are available,  
depending on the  
depth of the water and  
the advance speed  
you’ve set.  
To move back to echoes that were displayed within the past  
few minutes, continue pressing and holding the CURSOR PAD  
to the left.  
As you move the position marker with the CURSOR PAD, the  
marker speed accelerates to quickly scroll to the desired location.  
SoundTrac screen  
The lat/lon of the position marker is displayed at the bottom of  
the picture, along with the time elapsed since the ping, and the  
distance and bearing from your present position to the marker  
(assuming the navigator is providing position data.) As you  
move the position marker left and right, these coordinates  
change accordingly.  
NOTE:  
When you use the position marker on a split screen (showing either  
two frequencies, or zoom mode), each half of the screen has a posi-  
tion marker. Both markers designate the same physical location.  
Page 52  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Echoes from the last 3000 pings are stored.  
The number of minutes of past echo data available depends on  
two factors:  
the depth of the water  
the advance speed  
In deeper water, the 491 pings at a slower rate, so the echo  
sounder saves data over a longer period of time. A slower  
advance speed will have the same effect.  
Marking fish as waypoints  
The 961/962’s fish marking function lets you use SoundTrac  
to mark fish, wrecks, or any other objects that you see at any  
past echo displayed on the screen.  
To mark echoes as waypoints:  
1. At the ECHO screen, press the CURSOR PAD to the left to  
move the position marker—a dashed vertical line—to the  
position of the echo.  
2. Press MARK.  
A *MARK##* waypoint immediately appears on the  
SOUNDTRAC screen and on the CHART screen. Each  
marked echo becomes a waypoint (named *MARK##*)  
stored in the waypoint database. You can perform all of  
the usual waypoint functions, including going directly to  
this waypoint, adding it to the end of your trip, changing its  
name, etc.  
Navigating to a past echo position  
On the SOUNDTRAC screen, the GO TO function can be used  
for any of the following functions:  
to go directly to a past echo position  
to add a past echo position to the end of your trip  
to store a past echo position as a waypoint or avoidance  
point  
to make a new route with a past echo position as its first  
waypoint  
491 Echo Sounder Operations Manual  
Page 53  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
to add a past echo position to the end of an already dis-  
played route  
Going to a past echo position is described below. The other  
options are described in the Operator’s manuals for your  
Northstar navigator.  
To go directly to a past echo position (as long as the GPS is  
providing position data):  
Going directly to a  
past echo position  
1. On the SOUNDTRAC screen, press the CURSOR PAD left  
or right to move the position marker to the desired posi-  
tion, then press GO TO.  
The SELECTED CURSOR POSITION window appears.  
2. Press GO NOW.  
The navigator creates a new temporary waypoint called  
COORD and returns to the SOUNDTRAC screen. The  
COORD waypoint isn’t stored in the waypoint database;  
instead, it’s placed in the trip, where it replaces any future  
trip points. To see this current waypoint on the CHART  
screen, press CHART at any time. Your present vessel  
position and time have now become a past trip point.  
Page 54  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
7
Understanding the alarms . . . . . . . . . . . . . . . . 7-56  
Setting the fish alarm . . . . . . . . . . . . . . . . . . . . . 7-56  
Setting the bottom alarm . . . . . . . . . . . . . . . . . 7-58  
Setting the temperature alarm . . . . . . . . . . . . 7-60  
This chapter describes the echo sounder’s three alarm  
functions (for fish, bottom, and temperature conditions): the  
settings for each alarm, and how to turn them on and off.  
491 Echo Sounder Operations Manual  
Page 55  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Understanding the alarms  
The echo sounder’s alarms work just like the other alarms.  
Their status is updated every second, and their messages are  
displayed in the following ways:  
at the bottom of the ECHO screen, and also on various  
windows that may be overlaid onto these screens  
on the ALARMS screen  
On this screen, you can manually “clear,” or stop, new alarms,  
although some are auto-clearing, and you can view old alarms,  
which are alarms that already have cleared.  
To alert you automatically in situations related to echo  
sounding, you can set three alarms:  
fish alarm  
temperature alarm  
NOTE:  
You also can set the echo sounder to automatically save *FISH##*  
or *THERM##* waypoints, when fish or a certain temperature are  
detected, if the fish or temperature alarms are on. To automatically  
save these waypoints, see ”Number of special waypoints” starting  
on page 2-14.  
Setting the fish alarm  
When the fish alarm is on, an alarm sounds if an echo returns  
from either inside or outside specific upper and lower limits  
you’ve set.  
To set the fish alarm:  
1. At the ECHO screen, press MORE.  
2. Press ALARM.  
3. At the ALARM screen, press FISH ALARM.  
The options on the FISH ALARM window are on/off, echo  
strength level, upper and lower marker depths, and inside  
or outside markers.  
Page 56  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
4. Follow the instructions below for each of these five  
settings.  
Fish alarm window  
To set the fish alarm’s minimum echo-strength level:  
Setting the alarm’s  
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.  
Setting the upper  
and lower marker  
depths  
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  
Page 57  
Download from Www.Somanuals.com. All Manuals Search And Download.  
2. Press the CURSOR PAD up or down to set the depth, or  
use the KEYPAD to manually enter the desired depth.  
The depth is displayed in the tab below the SET UPPER  
MKR key.  
To set the depth of the lower marker:  
1. At the FISH ALARM window, press SET LOWER MKR.  
The lower marker window is highlighted in black.  
2. Press the CURSOR PAD up or down to set the depth, or  
use the KEYPAD to manually enter the desired depth.  
The depth is displayed in the tab below the SET LOWER  
MKR key.  
If you designate the markers as inside markers, the fish alarm  
sounds when fish are detected within these markers. If you set  
these markers as outside markers, the fish alarm sounds when  
fish are detected outside of these markers.  
Setting inside or  
outside fish  
markers  
To set the markers to inside or outside, at the FISH ALARM  
window, press INSIDE/OUTSIDE MKRS to toggle between the  
inside and outside settings. The setting is displayed in the tab  
below the INSIDE/OUTSIDE MKRS key.  
To turn the alarm on, at the FISH ALARM window, press TURN  
ALARM ON. Generally, you’ll want to turn the alarm on after  
making all the other settings.  
Turning the fish  
alarm on and off  
To turn the alarm off, press TURN ALARM OFF.  
When fish are detected, the alert tone sounds and the message  
“FISH!” is displayed. This message clears automatically after 20  
seconds and the alarm is rearmed.  
The alarm  
Setting the bottom alarm  
When the bottom alarm is set, an alarm sounds if the echo  
sounder detects that the bottom is shallower than the limit  
you’ve set.  
Page 58  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
To set the bottom alarm:  
1. At the ECHO screen, press MORE.  
2. Press ALARM.  
3. At the ALARM screen, press BOTTOM ALARM.  
The options on the BOTTOM ALARM window are on/off  
and the depth setting.  
Bottom alarm window  
You can set the depth level for the seabed, so that as soon as  
the bottom is shallower than this depth, the bottom alarm will  
sound.  
Setting the bottom  
level  
To set the bottom level, at the BOTTOM ALARM window, press  
the CURSOR PAD up or down to set the depth, or use the  
KEYPAD to manually enter the desired depth.  
NOTE:  
The 491’s depth indicator reflects the depth below your vessel’s  
transducer, not below the keel. Ask your installer for the exact dis-  
tance between your transducer and your keel. This value must then  
always be manually added to the 491’s depth indicator, or else  
entered into the transducer’s depth setting on the ECHO  
SOUNDER SETUP screen for an automatically correct reading.  
491 Echo Sounder Operations Manual  
Page 59  
Download from Www.Somanuals.com. All Manuals Search And Download.  
To turn the alarm on, at the BOTTOM ALARM window, press  
TURN ALARM ON. To turn the alarm off, press TURN ALARM  
OFF.  
Turning the bottom  
alarm on and off  
When the bottom is detected, the alert tone sounds and the  
message “Bottom Collision!” is displayed. This message clears  
automatically after 20 seconds, and the alarm is reset.  
The alarm  
Setting the temperature alarm  
When the temperature alarm is set, an alarm sounds if the  
echo sounder detects that the water temperature has either  
risen above or dropped below the limit you’ve set.  
This alarm isn’t present  
unless a temperature  
sensor is installed and  
configured.  
To set the temperature alarm:  
1. At the ECHO screen, press MORE.  
2. Press ALARM.  
3. At the ALARM screen, press TEMP ALARM.  
The options on the TEMPERATURE ALARM window are  
on/off, upper and lower limits, and inside or outside limits.  
Temperature alarm window  
Page 60  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
You can set the upper and lower temperature limits. When the  
water temperature is either inside or outside these limits, the  
temperature alarm will sound.  
Setting the upper  
and lower  
temperature limits  
To set the upper temperature limit:  
1. At the TEMPERATURE ALARM window, press SET UPPER  
LIMIT.  
The upper limit window is highlighted in black.  
2. Press the CURSOR PAD up or down to set the  
temperature, or use the KEYPAD to manually enter the  
desired temperature.  
The temperature is displayed in the tab just below the  
SET UPPER LIMIT key.  
To set the lower temperature limit:  
1. At the TEMPERATURE ALARM window, press SET  
LOWER LIMIT.  
The lower limit window is highlighted in black.  
2. Press the CURSOR PAD up or down to set the  
temperature, or use the KEYPAD to enter the desired  
temperature.  
The temperature is displayed in the tab just below the  
SET LOWER LIMIT key.  
If you set the upper and lower temperature limits as inside  
limits, the temperature alarm sounds when the temperature is  
detected within these limits. If you set these limits as outside  
limits, the temperature alarm sounds when the temperature is  
detected outside of these limits.  
Setting inside or  
outside  
temperature limits  
Press INSIDE/OUTSIDE LIMITS on the TEMPERATURE ALARM  
window to switch between the inside and outside settings. The  
current setting is displayed in the tab just below the INSIDE/  
OUTSIDE LIMITS key.  
To turn the alarm on, at the TEMPERATURE ALARM window,  
press TURN ALARM ON. To turn the alarm off, press TURN  
ALARM OFF.  
Turning the  
temperature alarm  
on and off  
491 Echo Sounder Operations Manual  
Page 61  
Download from Www.Somanuals.com. All Manuals Search And Download.  
When the temperature alarm sounds, an alert message is  
displayed. This message clears automatically after 20 seconds  
and the alarm is reset.  
The alarm  
Page 62  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
8
Troubleshooting 491 Operations  
Troubleshooting the echo sounder . . . . . . . 8-64  
Checking the transducer . . . . . . . . . . . . . . . . . . 8-65  
This chapter explains how to troubleshoot the echo sounder  
system before returning the equipment for factory service.  
491 Echo Sounder Operations Manual  
Page 63  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Troubleshooting the echo sounder  
No echoes displayed when STAR key is pressed.  
Is the  
Advance  
Speed set to  
zero?  
Change the Advance Speed  
setting.  
YES  
NO  
Is the  
961/962  
Contact Northstar Service to  
upgrade to the latest version  
of 961/962 software.  
NO  
NO  
software  
Version 3.0 or  
greater?  
YES  
Has  
Configure NMEA Port 3 for  
the 491. See Section 1 of  
this manual for instructions.  
NMEA Port 3  
been configured  
for the 491?  
YES  
491 is communicating with  
the navigator  
1. Check fuses and circuit  
breakers  
1. Check transducer  
connector for the  
STEADY  
GREEN  
2. Check power to 491 with  
a voltmeter.  
Check  
the 491's STAT  
indicator  
OFF  
proper wiring.  
3. Verify that the data cable  
between the 961/962 and  
the 491 is properly wired  
and connected.  
2. If wiring is correct,check  
transducer impedance  
with an ohmmeter.  
3. If the transducer is open  
or shorted, replace it  
FLASHING  
GREEN  
RED  
The 491 and the 961/962  
aren't communicating properly.  
Check the wiring of the data  
cable between the 961/962  
and the 491.  
There's a hardware problem  
with the 491.  
Figure 9: Troubleshooting the echo sounder (961/962)  
Page 64  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
No echoes displayed on sounder screen.  
Is the  
Advance  
Speed set to  
zero?  
YES  
Change the Advance Speed  
setting.  
NO  
Has the  
navigatorʼs  
Aux Port been  
configured  
for the  
Configure the navigatorʼs  
Aux Port for the 491. See  
Section 1 of this manual  
for instructions.  
NO  
491?  
YES  
491 is communicating with  
the navigator.  
1. Check fuses and circuit  
breakers.  
1. Check transducer  
connector for the  
STEADY  
GREEN  
2. Check power to 491 with  
a voltmeter.  
Check  
the 491's STAT  
indicator  
OFF  
proper wiring.  
3. Verify that the data cable  
between the navigator and  
the 491 is properly wired  
and connected.  
2. If wiring is correct,check  
transducer impedance  
with an ohmmeter.  
3. If the transducer is open  
or shorted, replace it  
FLASHING  
GREEN  
RED  
The 491 and the navigator  
aren't communicating properly.  
Check the wiring of the data  
cable between the navigator  
and the 491.  
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  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
transducer. The models below can be purchased from  
Northstar.  
Table 3: Northstar-recommended transducers  
Manufacturer Model  
Power  
1 kW  
Northstar P/N  
TD1004  
Airmar  
Airmar  
B260  
B744V  
600 W  
TD1005  
(w/3-wire speed)  
Airmar  
P66  
600 W  
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 trans-  
ducer is outside the scope of this manual. Refer to the transducer  
manufacturer’s documentation. Do not return a transducer to North-  
star. If you need to return a transducer for service, contact the man-  
ufacturer directly for instructions.  
Do not expose a transducer to gasoline or clean it with strong  
solvents. These can penetrate and degrade the housing. If a  
transducer will be exposed to saltwater, coat it with  
anti-fouling paint to prevent sea growth. To clean a transducer  
of sand, debris, or sea growth, use a stiff brush or putty knife.  
Use sanding sparingly, as repeated sanding may affect a  
transducer’s performance at high speeds. If necessary, wet  
sand with finer grade wet or dry paper. Check the transducer  
periodically.  
Maintaining a  
transducer  
Page 66  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
A
491 Features and Specifications  
Table 4: 491 echo sounder features  
Performance characteristics  
Output  
Single/Dual Channel, 50/200kHz, 600W  
Fish, seabed, temperature  
Alarms  
Update rate  
Auto modes  
10 Hz maximum (depends on water depth)  
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  
Page 67  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Table 4: 491 echo sounder features (Continued)  
Screen notations  
Echo data  
Seabed depth (various size digits)  
Frequency of each window  
Speed through water (if connected)  
Water temperature (if connected)  
Depth scale for each window  
Depth of depth marker  
Latitude/longitude of position marker and vessel  
Alarm status and auto/manual status  
Zoom mode  
Name of waypoint, and distance and bearing to  
waypoint  
Steering indicator  
Interfacing  
Connects  
Northstar 961/962 GPS Chart Navigator  
Northstar 957/958/6000i GPS Chart Navigator  
Northstar-recommended or compatible transducer  
Other  
Transducer outputs protected against open circuit/  
short circuit  
LED monitors input power and system status  
Physical characteristics  
Dimensions  
Weight  
8.78 x 7.22 x 2.35 inches  
2 pounds  
Environmental characteristics  
Temperature  
Protection  
Standards  
-25ºC to +60ºC operating temperature  
-55ºC to +90ºC storage temperature  
8 to 36 VDC, 8 Watts, reverse polarity and over-  
voltage protection  
Waterproof design meets the following: IEC60529  
IP6; IEC60945 emissions; CE mark  
Page 68  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Table 4: 491 echo sounder features (Continued)  
Manual controls  
Gain  
0 to 75 db  
0 to 9  
Clutter  
Signal level  
Noise limiter  
White level  
Other  
0 to 5  
ON/OFF  
Any single color  
Screen color palette  
Depth marker  
Position marker  
Zoom in/out  
Shift  
Ranges  
15, 30, 60, 120, 200, 400, 800, 1000, 2400 feet  
5, 10, 20, 40, 80, 150, 300, 500, 800 meters  
Advance  
speed  
1/8 to 2/1  
Depth units  
Feet, meters, fathoms  
Installation  
calibrations  
Include speed, temperature, gain, and transducer  
type  
491 Echo Sounder Operations Manual  
Page 69  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Page 70  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  
G
Glossary  
A-scope  
COG  
A horizontally magnified view of each echo, where the  
strength is shown by the width as well as the color of the line.  
Course-Over-Ground. The actual path of your vessel relative  
to the surface of the earth.  
clutter  
current  
default  
echo  
Distracting echoes caused by turbulence, plankton, etc. Can be  
reduced by the clutter control.  
The horizontal movement of water caused by tidal or other  
forces.  
A choice made automatically by the echo sounder; some  
defaults can be overridden in partial automatic mode.  
The sound returned by either an object below the water’s sur-  
face or by the seabed, when this object or seabed is detected  
by a sound wave.  
echo sounder  
An instrument that uses sound waves to measure the depth of  
a body of water or an object (such as a school of fish) below  
the water’s surface.  
fathom  
gain  
A depth measurement that equals six feet or 1.83 meters of  
water.  
The amount of amplification given to the received echo before  
it is displayed.  
GPS  
hue  
Global Positioning System.  
The gradations of a color.  
interference  
The electromagnetic interruption of a radio signal that causes  
a poor signal reception. Interference may originate from exter-  
nal sources, such as another nearby echo sounder, or from the  
vessel itself, such as alternator noise.  
latitude  
Imaginary lines on the earth's surface running East/West and  
expressed in degrees (0-90) north or south of the Equator.  
Used in conjunction with the North/South lines of longitude to  
determine position.  
491 Echo Sounder Operations Manual  
Page 71  
Download from Www.Somanuals.com. All Manuals Search And Download.  
longitude  
Imaginary lines on the Earth's surface running North/South  
and expressed in degrees (0-180) east or west of the Prime  
Meridian (a line running from the North to South Pole, passing  
through Greenwich, England).  
meter  
A unit of measurement (length) equal to 39.37 inches, slightly  
more than a standard yard.  
nautical mile (nm)  
An international unit equal to 6,076.115 feet (1,852 meters)  
used officially in the U.S. since 1959. A nautical mile is about  
800 feet more than a statute mile. One nm is equal to 1  
minute of latitude.  
ping  
SOG  
A pulse transmitted from the 491 echo sounder. Also, the act  
of transmitting a pulse from the echo sounder ("pinging").  
Speed Over Ground. The actual speed of your vessel relative to  
the earth, not the water.  
tide  
The vertical rise and fall of water caused by the gravitational  
pull of the moon and sun.  
transducer  
The device mounted through the hull to send and receive  
ultrasonic beams that determine seabed conditions and locate  
fish.  
waypoint  
A particular location, saved by marking fish on the echo  
sounder’s LIVE-DATA screen, which is used as an intermediate  
or final destination.  
Page 72  
491 Echo Sounder Operations Manual  
Download from Www.Somanuals.com. All Manuals Search And Download.  

Minolta Scanner Scanner Mode User Manual
NETGEAR Network Card XAVB6504 User Manual
NETGEAR Network Router DG834GFS User Manual
NordicTrack Home Gym NTBE01700 User Manual
Optiview Home Security System 10XSPD User Manual
Oricom Cordless Telephone pro600 DECT User Manual
OWI Speaker LGS120DVC User Manual
Ozark Trail Tent WMT 9900 User Manual
Panasonic Car Stereo System C7113U User Manual
Panasonic Laptop CF31UPL1Y1M User Manual