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
be used instead.
6000i
, information in Section 6 of its manual can
Northstar
a unit of Brunswick New Technologies Marine Electronics
30 Sudbury Road
Acton, Massachusetts 01720
Revision A
Part Number GM494
www.NorthstarNav.com
Service: 978/897-6600
Sales: 800/628-4487
Contents
1 Welcome
Welcome to the Northstar 491
Using this manual
Technical support
How echo sounding works
Powering the 491 on and off
Setting up the 491
2 Quick Start: Using the Echo Sounder
Displaying the echo sounder’s picture
Using demo mode
Introducing the displayed information
Using automatic mode
Changing the frequency of echoes
Zooming in and out
Setup functions
3 Adjusting the Echo Sounder Picture
The picture menu
Adjusting the gain (strong echoes)
Adjusting the clutter (weak echoes)
Adjusting the signal level (weak echoes)
Suppressing interference (the noise limiter)
Selecting the color bar (hue) and white level
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. 31
32
4 Understanding Depth Settings
Viewing the seabed depth
Viewing the depth marker
Changing the depth settings
Setting the picture’s shift (starting depth)
Setting the picture’s range
5 Other Functions: Using the MORE key
Using the MORE key
Changing the advance speed
Displaying the A-scope
Setting the ECHO screen data
. . . . . . . . . . . . . . . . . . . 42
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. . 37
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Introducing snapshots
Setting up the video image overlay
. . . . . . . . . . . . . . . . . 46
. . . . . . . 49
6 Reviewing past echoes using SoundTrac
Viewing past echoes using SoundTrac
Marking fish as waypoints
Navigating to a past echo position
7 Setting the Alarms
Understanding the alarms
Setting the fish alarm
Setting the bottom alarm
Setting the temperature alarm
8 Troubleshooting 491 Operations
Troubleshooting the echo sounder
Checking the transducer
. . . . . . . . . . . . . . . . . . . . . . . . . 55
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1
Welcome to the Northstar 491 . . . . . . . . . . . . . 1-2
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
T
his chapter introduces the
Manual
support and service, and describes the 491’s basic set-up and
power on/off procedures.
, explains how to contact Northstar for technical
Welcome
Northstar 491 Operations
491 Echo Sounder Operations Manual Page 1
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
491 Installation Manual
recommended transducers.
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.
Northstar
(part number GM495) for
CAUTION!
Using this manual
Organization
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 recommends installation and set-up by a qualified marine
technician. For installation procedures, see the Northstar
491 Echo Sounder Installation Manual (Part Number
GM495).
Chapter 1 introduces you to the 491 echo sounder and to this
operations manual.
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
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.
Conventions
Specific conventions are used to provide a consistent way to
recognize certain information, as follows:
• is the universal symbol used for caution and warning
information that pertains to your personal safety or prevents damage to the 491. The
boxes contain critical information—please read them!
•
•
•
• A bulleted list contains a series of related items or topics.
• A numbered list contains a series of steps in a procedure.
is the type style used for titles of reader notes. These
NOTE
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
display screens.
is the type style representing text on the
CAUTION
and
WARNING
491 Echo Sounder Operations Manual Page 3
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: service@northstarnav.com
Sales: sales@northstarnav.com
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:
www.northstarnav.com (you can send email to
Northstar directly from this site)
Hearing from you
Service and repair
Page
4
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:
docs@northstarnav.com
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.
491 Echo Sounder Operations Manual
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
called a “water column.” The transducer converts this echo
into a tiny electrical pulse. The 491 digitizes these pulses and
sends them to the navigator, so that echo sounding pictures of
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
GPS
antenna
957/958/6000i
Navigator
33-foot cable
(part of transducer)
491
module
10-foot cable
(Northstar-supplied)
Ship's
Power
10-foot cable
(Northstar-supplied)
Transducer
Figure 1: 957/958 echo sounder system components
GPS
antenna
Control
Head
33-foot cable
(part of transducer)
491
961/962
Processor
module
Page
6
10-foot cable
(Northstar-supplied)
Ship's
Power
10-foot cable
(Northstar-supplied)
Transducer
Figure 2: 961/962 echo sounder system components
491 Echo Sounder Operations Manual
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
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
PWR
until the screen goes dark.
Using 491 with the
961/962
• 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:
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
4. Check that the FORMAT option is set to “490.” If not, set it
now.
Using the 491 with
the 957/958
Before starting, you should double-check that the navigator’s
AUX port is set to the Sounder option:
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
ECHO
SCREEN
Figure 3:
STAR key
Auto
Picture
Frequency
Zoom
Depth
More
More settings
Alarms
Advance Speed
Snapshot
A-Scope
Data
Return
Data on-screen
Bottom box
Temp box
Temp graph
Speed
Return
Depth settings
Shift
Range
Bottom box
Return
Snapshot
Display
Rename
Archive
Erase
Return
Picture settings
Gain
Clutter
Noise Limiter
Hue
Signal level
Return
Alarm settings
Fish alarm
Bottom alarm
Temp alarm
Return
Figure 4: 961/962 echo sounder menu structure
491 Echo Sounder Operations Manual Page 9
ECHO
SCREEN
STAR key
Auto
Picture
Frequency
Zoom
Depth
More
More settings
Alarms
Advance Speed
Video
A-Scope
Data
Return
Data on-screen
Temp box
Temp graph
Bottom box
Speed
Return
Depth settings
Shift
Range
Bottom box
Return
Video setup
Video on
Return
Picture settings
Gain
Clutter
Noise Limiter
Hue
Signal level
Return
Alarm settings
Fish alarm
Bottom alarm
Temp alarm
Return
Figure 5: 957/958 echo sounder menu structure
Page 10 491 Echo Sounder Operations Manual
2Quick Start: Using the Echo Sounder
Displaying the echo sounder’s picture . . . . 2-12
Using demo mode . . . . . . . . . . . . . . . . . . . . . . . . 2-14
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
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
indicator
Water
temperature
box
Color
bar
Water
temperature
scale
Depth
box
Echo data
Depth Scale
Frequency
selection and
indicator
Navigation
information
Lat/lon of
vessel
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
Dist/brg
to waypoint
Steering indicator Speed, course, and speed
through the water
Figure 6: Illustrated ECHO screen
Depth
marker
and
indicator
Water
temperature
box
Color
bar
Water
temperature
scale
Depth
box
real-time echoes. For details, see “Reviewing past echoes using
SoundTrac” starting on page 51.
Echo data
Depth Scale
Position
marker
and
indicator
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
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 corresponding
*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
STAR to clear alarms
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.”
Displaying echo
sounder data on the
CHART screen
For the 961/962
For the 957/958
You can overlay a smaller version of the echo screen onto the
CHART screen.
To overlay the echo screen:
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:
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
Introducing the displayed information
The following information can be displayed on the ECHO
screen.
Echo sounding
Depth and
temperature
• echo sounder data
• 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 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 connected; can be turned off)
Navigation
Status tabs
491 Echo Sounder Operations Manual Page 15
• vessel’s current lat/lon (on the SOUNDTRAC screen, this
lat/lon indicates the position marker’s location)
• vessel’s SOG and COG
• active waypoint, if any, and graphic steering indicator
• vessel’s Speed Through the Water (if speed sensor is connected; 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.
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.
Cruising or fishing
The status tabs
Automatic mode has two variations: autocruising and
autofishing.
• 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.)
Page 16 491 Echo Sounder Operations Manual
Manually
overriding
automatic mode
You can always manually change any of the echo sounder’s
settings: the gain, clutter, noise limiter, shift, and range.
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 resolution.
Less resolution is better at finding
big fish, but may miss the bait
fish.
Wider beam is good for seeing
fish not directly beneath the boat.
Shorter wavelength provides a
sharper picture, but can’t go as
deep.
Finer resolution is better at finding small fish (baitfish) and subtle
bottom details.
Narrower beam is very focused.
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:
491 Echo Sounder Operations Manual Page 17
• the zoom function magnifies the frequency on the right
side
• 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
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.
Choosing the zoom
scale
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.
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’.
Choosing a zoom
mode
491 Echo Sounder Operations Manual Page 19
Press ZOOM on the ECHO screen to cycle through the four
zoom modes (and choose the one you want):
• bottom zoom
• bottom lock
• bottom lock/center
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