Northstar 941X User Manual
Northstar 941X
Refe rence Manual
SOFTWARE VERSION 2.05
30 SUDBURY ROAD
ACTON, MASSACHUSETTS 01720
(508) 897-6600
Copyright 1994, 1995, 1996 Northstar Technologies P/N GM1100 Doc. Rev D
WARRANTY
Northstar Technologies, a Divisi on of CMC E lectr onics, Inc., wa rr ant ees it s pr oducts
to be free from defects in material and workmanship for a period of two (2) years
from the date of shipment to an authorized dealer. This warranty applies to the
original purchaser or subsequent owner.
This warranty covers repair and/or replacement, at our option, of any part or parts
found to be defective, provided such defects in our opinion are due to faulty material
or workmanship and are not caused by tampering, abuse, or normal wear.
All warranties are F.O.B.: Northstar Technologies
30 Sudbury Road
Acton, Massachusetts 01720
This warranty applies only to products in normal use. It does not apply to units or
circuit boards defective due to improper installation, physical damage, tampering,
lightning or other electrical discharge, receivers or ma inframes subjected to fresh
water or saltwater immersion*, units with altered serial numbers, or units repaired
by unauthorized persons or in violation of Northstar service procedures.
The foregoing are the only warranties expressed or implied. No other warranty
exists.
Northstar assumes no responsibility for any conseq uential losses or damages of any
nature with respect to any products or services sold, rendered, or delivered.
*
Certain Northstar control heads are warranty protected against damage due to
water leakage, provided the head has not been tampered with.
IMPORTANT NOTICE
Although Northstar products are designed to be very useful navigation tools, they
are not substitutes for good seamanship. T he prudent navigator should never rely on
any single device as the sole source of navigation guidance. Exercise caution and
good judgment whenever underway.
!
1
2
C
CONTENTS
ONTENTS
CC
ONTENTSONTENTS
The Northstar 941X
The Northstar 941X
The Northstar 941XThe Northstar 941X
Introduction ................................................................. 2
Upon First Start-up ......................................................2
Using This Manual........................................................3
941X Features...............................................................4
941X Functions............................................................. 5
Comparing GPS and Loran .......................................... 5
Mounting Basics ...........................................................9
Special Functions..........................................................9
The Display Screen.....................................................10
Interfacing Capability..................................................11
Using the Controls
Using the Controls
Using the ControlsUsing the Controls
POWER Key................................................................ 14
CONTRAST Key.......................................................... 14
SAVE/MOB Key...........................................................15
Function Keys.............................................................16
Menu Keys....................................................................17
Cursor Keys..................................................................17
Keypad .........................................................................17
Special Display Windows ........................................... 18
!
3
Basic Navigation
Basic Navigation
Basic NavigationBasic Navigation
Displaying Position, Heading & Speed ......................22
Position Plotter...........................................................22
Using GPS...................................................................25
Using DGPS ................................................................26
Using Loran ................................................................30
Using Phantom Loran ................................................32
4
5
Creating Waypoints and
Creating Waypoints and
Creating Waypoints and Creating Waypoints and
Routes
Routes
RoutesRoutes
Entering Data..............................................................36
Creating Waypoints....................................................37
Avoidance Areas .........................................................39
Waypoint Lists............................................................ 41
Coordinate Options ....................................................42
Updating Waypoint Coordinates ...............................42
Editing Waypoints......................................................43
Transferring Waypoints to a PC.................................44
Creating Routes ..........................................................44
Saving a Route ............................................................47
Changing a Route........................................................50
Waypoint & Route Navig
Waypoint & Route Navigaaaation
Waypoint & Route NavigWaypoint & Route Navig
Quick-Start Waypoint.................................................54
Navigating to Waypoints............................................ 55
Navigating Along Routes............................................59
Restarting the Course Line......................................... 61
tion
tiontion
6
The NAV LOG Function
The NAV LOG Function
The NAV LOG FunctionThe NAV LOG Function
What NAVLOG Does ..................................................64
Logging Your Trip.......................................................65
Changing Your Trip ....................................................65
Adding Waypoints to the Trip....................................66
7
8
9
Other Special Functions
Other Special Functions
Other Special FunctionsOther Special Functions
Alarms.........................................................................68
Screen Backlighting.....................................................71
TideTrack™..................................................................71
Internal Differential Beacon Receiver ....................... 74
Customizing the 941X
Customizing the 941X
Customizing the 941XCustomizing the 941X
Time of Day.................................................................78
Display Options ..........................................................78
Navigation Options.....................................................82
Receiver Options.........................................................87
Port Setup Options .....................................................90
Service Options........................................................... 91
Geodetic Datum..........................................................94
Installation and Interfacing
Installation and Interfacing
Installation and InterfacingInstallation and Interfacing
Mounting the 941X...................................................100
Wiring the 941X System........................................... 102
Antenna Location .....................................................104
DGPS Antenna Coupler (ACU).................................108
Interfacing the 941X..................................................112
Programming the Output Ports ................................115
Appendix
Appendix (Specifications) ........................................129
AppendixAppendix
Glossary
Glossary..................................................................... 135
GlossaryGlossary
Index
Index .........................................................................138
IndexIndex
Figures
Figures
FiguresFigures
Tables
Tables
TablesTables
IGURE
F
F
F
F
F
F
F
F
F
F
F
F
F
T
T
T
T
T
T
T
T
T
1—MAX. P
IGURE
2—Y
IGURE
3—R
IGURE
4—941X GPS-O
IGURE
5—941X C
IGURE
6—S
IGURE
7—F
IGURE
8—C
IGURE
9—ACU A
IGURE
10—PL 259 (UHF) C
IGURE
11—I
IGURE
12—200 PPNM O
IGURE
13—941X D
ABLE
1—D
ABLE
2—I
ABLE
3—P
ABLE
4—NMEA 0183 S
ABLE
5—C
ABLE
6—C
ABLE
7—N
ABLE
8—Y
ABLE
9—C
OSITION VARIANCES WITH UNCORRECTED
OKE MOUNT DRILLING DIMENSIONS
EAR CONNECTORS
OMBO
TRIPPING THE COAX CABLE JACKET
LARED CABLE BRAID
OMPLETED
NTERFACE CONNECTOR (MATING SIDE
ATUM LIST
NTERFACE CONNECTOR PINS
ORT SETUP OPTIONS
ONNECTION TO NORTHSTAR
ONNECTION TO NORTHSTAR
ORTHSTAR
EOMAN ELECTRONIC PLOTTER SETUP WITH
ONNECTING TO EXTERNAL
BNC C
SSEMBLY
IMENSIONS
.....................................................................97
800 S
......................................................103
NLY ANTENNA
GPS/DGPS A
(AN145 & AN150)..........105
NTENNA
..................................................108
ONNECTOR
...........................................................110
ONNECTOR
UTPUT BLOCK DIAGRAM
........................................111
......................................................132
........................................114
.....................................................116
ENTENCE IDENTIFIERS
800 P
800 P
ERIES OUTPUT PORT SETUP
NS B
...........................102
(AN190).............105
............................107
....................................108
)...................... 113
........................115
.............................120
ORT
A.....................123
ORT
B..................... 123
EACON RECEIVER
GPS....8
...............123
941X.......124
......125
1
Introducing the Northstar 941X
Introduction 2
Upon First Start-up 2
Using This Manual 3
Features 4
Functions 5
Comparing GPS and Loran 5
Mounting 9
Special Functions 9
The Display Screen 10
Interfacing Capability 11
his section introduces you to the Northstar 941X navigator, outlining its various operational functions, in-
stallation configurations, and specifications.
Use this section to get a quick overview of what the 941X is
all about, and how you can use it to your best advantage.
Rev. D 1 — Introduction
1 — Introduction Page 1
1 — Introduction1 — Introduction
Introduction
HE NORTHSTAR 941X combines 12-channel GPS navigation with
T
Differential GPS capability, a high-definition display, loran compatibility, built-in tide data up to the year 2010, and many other navigation
features.
For the ultimate in GPS accuracy, the 941X may be purchased as the
941XD, featuring an internal DGPS (Differential GPS) receiver. This advanced system gives you even greater accuracy by accepting Differential
GPS signal “corrections” from shore-based transmitters (called “beacons”), and using them to display position fixes as accurate as 2-5 meters. You can also connect your 941X to any external source of DGPS
corrections meeting the SC-104 standard (such as the Northstar 8800
DGPS Sensor).
Upon First
Start-up
When you turn your 941X on for the very first time, you may be greeted
with a flashing exclamation poin t symbol in the lower right portion of the
GPS POSITION
the status box at the top. The flashing exclamation point simply means
that an alarm message is present and waiting for your acknowledgment.
To see the message, press the
BACKLIGHT
screen, and the word
screen will be displayed.
ACQUIRE
STAR
key once. The
SKY SEARCH
or
ALARMS AND
in
Page 2 1 — Introduction
1 — Introduction Rev. D
1 — Introduction1 — Introduction
The alarm message
date, are shown in the
upper right corner of the box indicates that this is a previously unacknowledged message.
This sequence is a normal part of powering-up the 941X for the first
time, as it notifies you that it is in the process of acquiring satellite information necessary for navigation. It normally takes only two to five
minutes to acquire this data, after which the 941X is ready to navigate.
(This alarm condition usually occurs in units sh ipped to customers located more than several hundred miles from the Northstar factory, and
only the first time the 941X is turned on after being installed.)
NO GPS POSITION FIX
RECEN T ALARM S
box. The word
, along with its time and
NEW
in the
Using This
Manual
"
Press the
acknowledge and clear the message. Press the
left of the screen to return to the main
is now ready to navigate. (For more on alarms, see page 68. If you wish
to proceed directly to navigating with the 941X, skip to page 22.)
Your 941X was designed to be an easy-to-use, full-function GPS navigator, understandable in the information it displays and dependable in its
performance. This Reference Manual is intended to complement that
ease of use by illustrating and describing th e 941X’s various functions in
a format helpful to quick learnin g and safe operation.
The sections in this manual are grouped by relat ed functions, beginning
with an overview of basic control panel layout and function commands,
and gradually progressing to more advanced waypoint and route navigation operations. Sample screen images are used throughout to help illustrate what the 941X displa y screen looks like for the function being
described.
The “helpful hand” (pictured at left) is a convenient shortcut that leads
you directly to step-by-step instructions. You can also use it as a quickreference for locating less-frequently-used operations.
CLEAR ALARM
menu key to the right of the display screen to
POSITION
GPS POSITION
key below the
screen. The 941X
Rev. D 1 — Introduction
1 — Introduction Page 3
1 — Introduction1 — Introduction
Features
Upon using the 941X, you’ll see that you can actually learn to operate the
system’s various features without consta nt referral to th is manual. After
you’ve read through it once, you won't have to refer to it very often again .
Since the 941X anticipates your most frequent requests for navigation
information, accessing most functions req uires only one or two button
pushes. By minimizing the attention needed to navigate, you can now
devote more time to other aspects of your trip.
GPS features
navigation
features
waypoints and
routes
• accurate, worldwide position data in any weather, 24 hours a day
• optional internal DGPS (Differential GPS) Beacon Receiver for
accuracy as good as 2-5 meters
• fast signal acquisition
• fast-reacting, accurate speed and course
• lat/lon display
• built-in plotter shows:
1) your position relative to nearby waypoints;
2) your rece nt track line;
3) your intended course line; and
4) avoidance areas,
all against a latitude/longitude grid.
• tide prediction software integrated with navigation display (at
any NOAA tide station; for today or any other date.)
• stores up to 1,000 waypoints and 500 routes
• displays waypoints:
1) in alphabetical order
2) in order of distance from your present position
3) saved with the
4) stored as avoidance points
• plots position of:
1) nearby waypoints
2) routes
3) avoidance areas
SAVE
button
Page 4 1 — Introduction
1 — Introduction Rev. D
1 — Introduction1 — Introduction
Functions
Five keys on the 941X instantly select the most commonly used functions, as described below:
POSITION
Speed- and Course-Over-Ground, and Time and Date are also displayed.
An alternate position screen plots your position graphically, along with
any nearby waypoints and your track history.
STEER
waypoint. It also displays your Cross Track Error, Estimated time to
waypoint, Estimated Time of Arrival, Course Over Ground, Speed Over
Ground, Speed of Advance, etc.
(
and accesses setup functions for customizing the operation and displays
of your 941X, including screen brightness.
WAYPTS/ROUTES
navigation.
NAV LOG
trip) and lets you modify it.
displays position coordinates as
1) GPS lat/lon coor dinates
2) loran TDs, if you have a loran receiver interfaced to the unit
3) or calculated “Phantom Loran” TDs if you don't.
shows how to steer precisely along a course line to your current
STAR
) (The
key) displays alarm conditions and tide information,
lets you enter or access waypoints and routes for
displays the progress of your current navigation plan (toda y’s
In addition to these function keys, the
your position as a waypoint, and provides a Man Overboard function for
returning to the saved point.
MENU KEYS
Five
tween specific choices displayed on the screen.
Comparing GPS
and Loran
The nation’s GPS system has received much publicity, often descri bed as
providing the ultimate in navigation accuracy for all applications. Its
major advantage over all other commercially-available navigation systems, including loran, is its all-weather, worldwide availability and
solute accuracy
device to determine your actual latitude and longitude coordinates on
the surface of the earth, as compared to position information determined
Rev. D 1 — Introduction
1 — Introduction Page 5
1 — Introduction1 — Introduction
on the right edge of the display are used to select be-
. (
Absolute accuracy
SAVE/MOB
key instantly saves
ab-
refers to the ability of a navigation
from a chart or other r eference.
to return to a position whose coordinates you have previously recorded
with the same equipment.)
Developed by the United States Department of Defense (DOD) the GPS
system of 21 active satellites (with 3 additional spar es) literally encircles
the earth with naviga tion information. GPS is offered in two forms: for
military users and for civil users.
Repeatable accuracy
refers to the ability
selective
availability
GPS and DGPS
With GPS available to virtually anyone around the world, the DOD
wanted to avoid the possibility that its precision could be used by hostile
forces as a source of accurate targeting data against U.S. interests. To
guard against such actions, they introduced intentional errors into the
GPS signals that only U.S. forces could bypass. Called
(or SA), it involves a complex formula of data encryption that can
ability
ability
abilityability
be turned on or off without the end-user ever knowing for sure whether
it is in effect or not. DOD’s stated position is that SA will remain in effect
indefinitely.
Selective Availability effectively reduces GPS’s absolute and repeatable
accuracy from 30 meters (roughly 100 feet) 95 % of the time, to 100 meters (330 feet) 95% of the time. This means that, with SA, you can expect
to be within 300 feet of your intended position 95% of the time, and beyond that area approximately 5% of the time. At first, this was accepted
by most end-users as an inevitable part of GPS, a tradeoff against its
global availability. But it didn’t meet the Coast Guard’s requirement of 820 meter accuracy for navigating harbors. It was then that a system of
differential corrections
them to effectively circumvent SA’s built-in errors.
was developed by the Coast Guard that enabled
Selective Avai
Selective Availlll----
Selective AvaiSelective Avai
These differential corrections are generated by fixed “refer ence stations”
and broadcast by marine radiobeacons over a relatively limited area—
usually a maximum broadcast radius of 250 miles—to Differentialcapable GPS (DGPS) receivers. The precise geographic location of the
reference station is used to calculate corrections based on the GPS data
received from the satellites, and the corrections are then broadcast to
DGPS receivers. The receivers then convert this data into extremely
precise position, heading and speed information. (Referred to as
Page 6 1 — Introduction
1 — Introduction Rev. D
1 — Introduction1 — Introduction
“beacons,” the transmitters are being situated at various locations along
the U.S. coastline and Great Lakes, most of which are former marine radiobeacon sites.)
With DGPS, navigators are guar anteed position accur acy on the or der of
2-5 meters
much better). Lat/lon positions displayed to thousandths of minutes
(roughly 6 feet) are common with DGPS. When using a radar or electronic plotter, DGPS corrections improve the steadiness of your displayed plot line dramatically.
In addition to accurate positioning information, DGPS provides critical
“integrity monitoring” of the received GPS signals, enabling the user to
be notified in seconds (as opposed to hours, with uncorrected GPS) that
an anomaly has been detected in a transmitted satellite signal. The integrity monitor instructs the DGPS receiver not to use data from the satellite in question.
50% of the time, and to 10 meters 95% of the time (usually,
loran
Loran, on the other hand, can still outperform non-differential GPS—
when SA is in effect—in
weather and characterized by a relatively limited range (when compared
to GPS), it’s a dependable system familiar to thousands of boat owners.
Since the 1970’s, LORAN users have relied upon that system’s ability to
repeatedly get them back to a previously-saved location with extreme
accuracy. Fishermen especially appreciated this capability because each
subsequent visit to a lobster trap or buoy was virtually “on the mark,”
saving them valuable time and money. Loran’s
superior to anything else commercially-available at the time.
In very good coverage areas, loran can typically get you to within 50 feet
(or roughly 14 meters) of your previously-visited target. On the other
hand, at its very best, uncorrected GPS with SA enabled will get you to
within
300 feet
uncorrected GPS—with variations of up to 300 feet in displayed position—wouldn’t be much help in getting you through a narrow channel.
Since most loran chains were configured for optimum coastline navigation, it’s easy to see why loran’s
masters and fishermen well for the last 25 years.
(100 meters) of your intended destination. Obviously,
repeatable accuracy
repeatable
. Though susceptible to
repeatable
accuracy has served harbor-
accuracy was
Rev. D 1 — Introduction
1 — Introduction Page 7
1 — Introduction1 — Introduction
Loran, however, isn’t as proficient as GPS in
absolute accuracy
, or visiting a spot for the first time. Since it transmits at a relatively low frequency (100 kiloHertz—similar to that on your AM radio), your ability to
get an accurate position “fix” is directly related to: 1) your distance from
the loran transmitters, and 2) the weather between you and the transmitters. It’s in these two areas that GPS consistently excels when it
comes to
absolute
accuracy.
Even with SA, GPS provides an
absolute
accuracy of around 300 feet
nearly everywhere in the world, under virtually any conditions. With a
“constellation” of satellites orbiting the earth and transmitting their position data on an extremely high frequency (1.575 GigaHertz, or 1.5
cycles per second), GPS is impervious to weather and your location
lion
bil-
on the surface of the earth. You can receive position fix es at any time,
anywhere, in any weather. This far surpasses the
absolute
accuracy that
is achievable from a good loran receiver in a strong signal coverage area,
in favorable weather conditions: usually 600 feet.
If you are accustomed to using your Northstar loran’s
repeatable
accuracy to return to within a boat length of a lobster trap or a buoy, time after time, you will not necessarily see this same performance with
uncorrected GPS—you could be as much as 600 feet from your expected
position. This will be especially apparent when using the 941X’s plotter
screen (without DGPS), where you may see your boat’s plotted position
appear to wander around within an area up to 600 feet in diameter (see
Figure 1 below).
Position circle of 300-foot radius,
showing possible 600-foot error
between fixes.
ACTUAL
40°00.000 N
72°00.000 W
Figure 1—Max. Position Variances with Uncorrected GPS
Page 8 1 — Introduction
1 — Introduction Rev. D
1 — Introduction1 — Introduction
300’
300’
You could be
anywhere within
the circle, 95% of
the time.
getting more
accuracy
If you need a higher level of accuracy than what basic GPS provides,
there are two choices available to you:
Mounting
1. Use
2. Interface your
The 941X is designed to be yoke- or flush-mounted on your boat. The
unit is waterproof and can be exposed directly to the weather. The GPS
antenna should be mounted fairly low on th e vessel to minimize the effects of pitch and roll, and where it has a clear view of the entir e sky. Th e
Beacon Receiver antenna (if installed) should be mounted fairly high,
like a loran antenna. Refer to “Mount ing the 941X,” on page 100, for details.
Differential GPS
beacon receiver (or use an externally-located Northstar differential
beacon receiver), or other source of differential corrections for your
941X. DGPS should provide better than 10-meter accuracy (repeatable and absolute) 95% of the time. See “Using GPS” on page 25 for
more information.
the appropriate NMEA 0183 format output capability). You will
then keep the “repeatable accuracy” of your loran, and add all of
the navigation features of the 941X, including the excellent worldwide “absolute accuracy” of GPS. Refer to Table 2 on pa ge 114 for
connector pin wiring guide.
by installing a Northstar internal differential
loran receiver
to your 941X (provided the loran has
Special
The following functions are unique to the 941X; you may want to read
about them in detail before using them.
Functions
loran TDs
Rev. D 1 — Introduction
The 941X automatically converts GPS coordinates to loran TDs for those
who have lists of fishing spots and other waypoints recorded as TDs. This
feature is called Phantom Loran™. You can display your position as TDs
or enter waypoints as TDs. The accuracy to be expected from this conversion is generally better than 500 to 1500 feet. You can also interface your
existing loran receiver to the 941X and then display and navigate with
1 — Introduction Page 9
1 — Introduction1 — Introduction
real-time loran TDs. These features greatly ease the transition from using
loran to using GPS. See page 30 for further details on using loran TDs.
plotter functions
TideTrack™
The Disp lay
Screen
The 941X’s plotter provides a picture of your position, and of what is
around you. Nearby waypoints, avoidance areas, and a lat/lon grid may
be displayed along with an image of your boat.
When you are using the plotter, the five menu keys below the display
screen allow you to perform the following functions:
1) restart the desired track line to run directly from your position to the
waypoint, “zeroing” the cross-track error display
2) change the options available for the plotter
3) center the image of the boat on the screen
4) zoom in to show more detail
5) zoom out to show more area
See page 22 for more information on using the plotter.
TideTrack displays a 24-hour tide graph for any of over 3,000 NOAA tide
stations covering the entire U.S. coast, including Alaska and Hawaii, as
well as much of the western Canadian coastline. Tides may be shown for
today or any other day you ch oose. See page 71 for more information on
using TideTrack.
The Liquid Crystal Display (LCD) and all controls are lighted for nighttime use. The display is easily readable under all conditions, from full
sunlight to total darkness. Anti-ref lection treatment of the display and its
window eliminates over 90% of the reflection and glare. Important data
can be displayed using large numbers which can be seen from a distance.
To adjust the bright ness, press th e
DIM
and
trolled by the
cleaning the
screen
Page 10 1 — Introduction
Use caution when cleaning the plastic window in front of the display
screen. Although it is resistant to scratches, it can be damaged if you
wipe dirt off with a dry cloth. Always use a damp cloth when wiping t he
window. Use a small amount of window cleaner or alcohol to dissolve
menu keys to set the desired illumination. Contrast is con-
ARROW
1 — Introduction Rev. D
1 — Introduction1 — Introduction
key to the left of the screen.
STAR
key (
) and use the
BRIGHT
any oil or grease on the screen. Whenever possible, avoid touching the
window with your fingers, as natural oils from your hand will temporarily degrade the characteristics of the window and cause your finger prints
to appear as bright reflections. These will disapp ear when the screen is
cleaned as described above.
CLEANING HINT
CLEANING HINT
Pre-packaged moist towellettes (especially those containing a
small amount of alcohol) are excellent for cleaning t he display
window. You might wish to keep a supply on hand to wipe off
fingerprints and other smudges.
CLEANING HINTCLEANING HINT
Interfacing
Capability
The 941X contains two independent output ports for driving NMEAcompatible devices, two input ports for accepting data from other NMEA
devices, and an auxiliary port reserved for future use. It also features an
RS-232 port for input or output of SC-104 DGPS corrections, and waypoint/route or software program loading from a PC. The 941X can be
interfaced to a wide variety of devices, including autopilots, plotters, radars, etc. Refer to “Interfacing the 941X,” beginning on page 112, for
more information.
Rev. D 1 — Introduction
1 — Introduction Page 11
1 — Introduction1 — Introduction
Page 12 1 — Introduction
1 — Introduction Rev. D
1 — Introduction1 — Introduction
2
Using the Controls
POWER Key 14
CONTRAST Key 14
SAVE/MOB Key 15
Function Keys 16
Menu Keys 17
Cursor Keys 17
Keypad 17
Special Display Windows 18
HIS SECTION describes each of the Northstar 941X's
controls. Use this section for learning what each con-
trol does and for an overview of usin g its various functions.
Rev. D 2 — Using the Controls
2 — Using the Controls Page 13
2 — Using the Controls2 — Using the Controls
HE MAJOR FUNCTIONS of each of the 941X's controls are de-
T
scribed in this section.
POWER Key
Press the
special startup screen that includes an owner-identification message
which you may customize to aid in theft-prevention. Next, the 941X displays the results of the internal self-tests that are automatically run each
time the unit is turned on. Finally, navigation data is displayed.
If any of the six major components of the 941X fails the self-test, the notification
acknowledge it with the press of any function key (located below the display screen). Return the 941X to the factory for service.
POWER
SYSTEM TEST: FAILED
switch briefly to turn on the 941X. The unit displays a
will remain on the screen until you
To turn the 941X off, press the
one full second until the unit turns off.
CONTRAST Key
Page 14 2 — Using the Controls
Liquid Crystal Display (LCD) screens require a contrast adjustment to
compensate for different viewing angles, temperature conditions, etc.
The 941X's contrast control allows you to adjust its display screen to give
the best picture for your current condit ions. Pressing the upper contrast
arrow darkens the screen, and pressing the lower arrow lightens it. Adjust the screen for the best contrast as seen from your normal operating
location.
2 — Using the Controls Rev. D
2 — Using the Controls2 — Using the Controls
POWER
switch and hold it in for at least
SAVE/MOB Key
SAVE/MOB
The
It does this in either of two ways, depending on whether you press the
key briefly, or press and hold it.
key is used to save your current position as a waypoint.
saving a
waypoint
Man Overboard
feature
Press the
new waypoint will automatically be given a name, such as –S002–,
where the letter S indicates a saved waypoint, and the 3-digit number
increases by one every time you save a waypoint.
The waypoint’s 3-digit number will “wrap around,” or revert, to –S001–
when the 941X has reached the limit you set using the
WPT #
Press and hold the
Overboard” (MOB) mode. The 941X saves your position and displays it
in the plotter screen as an “X.” The plotter screen is locked on the display, showing your position and the MOB location. The MOB location
immediately becomes your current waypoint, with new bearing and distance information displayed on the right-hand side of the screen.
SAVE/MOB
function under
SAVE/MOB
button briefly to simply stor e your position. Th is
MAX SAVED
DISPLAY OPTIONS
button for three seconds to enter “Man
(see page 80).
INVOKING MOB WHILE USING AN AUTOPILOT
Some autopilots will attempt to steer your boat according to
any bearing changes output by the 941X, regardless of the severity of the change. Others automatically disengage when a
severe or abrupt turn is required. Please refer to your autopilot
manual for information regarding this procedure.
Rev. D 2 — Using the Controls
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To leave MOB mode and return to normal navigation, press
for at least three seconds.
SAVE/MOB
Function Keys
POSITION key
“Where am I?
STEER k ey
“How do I
get to my
waypoint?”
The five function keys located below th e display screen control wh at the
941X is doing. Any function key may be pressed at any time to display
the information you need to see.
POSITION
The
plotter screen to show your position graphically, relative to nearby waypoints and your track history. Course-Over-Ground and Speed-OverGround are displayed at the bottom of the screens.
Position coordinates may be shown as any of the following:
1) Lat/lon from GPS
2) Lat/lon from an external loran receiver
3) loran TDs from an external loran receiver
4) Phantom Loran TDs which the 941X calculates fr om its GPS coordinates
STEER
The
picture of your position relative to the course line is displayed, along with
all the numeric information you need to steer directly to your waypoint.
Two versions of the steer display are avai lable. Press
the version you were last using. Press it again to see the other version.
key displays your position coordinates, or displays a
key shows how to steer to a waypoint you h ave desi gnat ed. A
STEER
once to see
STAR
STAR key
WAYPTS and
ROUTES key
“Where do I
want to go?”
Page 16 2 — Using the Controls
The
alarms and messages the 941X has waiting for you. The second press
displays information about tides for your choice of over 3000 NOAA tide
stations. The third press displays the time of day, and the time of today’s
sunrise and sunset. The fourth press displa ys a menu of setup and customization functions used whenever you wish to change the way the
941X works for you.
The
access a library of waypoints and routes that you have entered previously, or specify where you want to navigate to.
See Sections 4 and 5 for waypoin t and route information.
key (
WAYPTS/ROUTES
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) has several functions. The first pr ess displays any
key allows you to enter waypoints and routes,
NAV LOG key
“How am I
doing?”
NAV LOG
The
you to change those ahead of you. See “What NAV LOG Does,” on p age
64, for more information.
key displays the waypoints you have passed, and allows
Menu Keys
Cursor Keys
Keypad
entering
numbers
The five round
used for different purposes depending on what function is currently being used or displayed. The function of each key is labeled on th e screen,
and pressing the key performs the displayed function.
A large cursor pad in the upper right corner of the 941X allows you to
move the flashing cursor on the display screen to the data you want to
display or change. For example, when entering data (such as a waypoint’s name or coordinates) press the down arrow to move the cursor
downwards to a particular field of data and press the right arrow key to
move the cursor to a particular character in that fiel d.
The 12-button alphanumeric keypad is used for entering numbers, letters
or special characters for waypoint coordinates, names, etc.
When the 941X is expecting you to enter numbers only, such as for waypoint coordinates, the keypad keys enter one digit, 0-9, with each keypress. The flashing cursor moves automatically to the next digit position.
MENU
keys on the right side of the display screen are
For entries such as latitude and longitude—where the digits must be entered into specific characte r positions—the cursor starts on the left side
of the field and characters are entered left to right into their correct positions.
For other numeric entries such as dist ances—wh ere a number of var ia ble
length may be entered—the digits are entered calculator-style from the
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right side of the field. If you make a mistake, you can press
clear the entire number and re-enter it, or you can press the left-arr ow
cursor key to reenter particular digits, one at a time.
CLEAR
to
entering letters
"
CLEAR and
ENTER keys
When the 941X is expecting letters to be entered, such as waypoint
names and descriptions, the operation is slightly different. Each key is
labeled with three letters (or other special characters) and a digit.
For example, the upper left key is labeled with the letters A, B, C and the
digit 1. Pressing the key one time displays the letter A. Press the key
again to display the second letter, B. Pressing a third and fourth time
displays the letter C and the digit 1, respectively. A fifth press br ings you
back to the letter A again.
To enter a character, first find the key containing the character, and
press that key one to four times to display the desired character. Finally,
move the cursor to the next character position by pressing the right arrow symbol on the cursor key.
The keypad also contains
ing data that has been typed on the keypad. Pressing the
always the last step when entering or changing data, or acknowledging
an action. The
ENTER
you changed it.
CLEAR
, and sets the field to all blanks or restores it to its value before
CLEAR
key removes any data you typed before you press
and
ENTER
keys for erasing or enter-
ENTER
key is
Special Display
Windows
alarm messages
Page 18 2 — Using the Controls
Occasionally, the 941X needs to inform you of someth ing or ask permission to do something. When this happens, a special information or question window appears on the display. The window contains an
exclamation point (“
and a message for you to read.
Alarm messages contain information you should read right away. Alarms
are communicated by the flashing exclamation symbol in the bottomright portion of the display.
Press the
BACKLIGHT
edge and clear the message.
STAR
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!!!!
”), an “
key once to show the alarm condition on the
screen. Press the
INFO
” label, or a large question m ark (“
CLEAR ALARM
menu key to acknowl-
”),
?
ALARMS &
information
windows
Information windows
control functions. They give you extra details pertaining to wha t is about
to happen, or let you acknowledge a command. Information windows
always appear with the word “
are displayed while you are entering data or using
”
INFO
in a small box.
question windows
Rev. D 2 — Using the Controls
Question windows
what you want to do. A question mark will always appear in this type of
window.
You must respond to any question window by pressing
“YES,” or
keys, are inactive when a question window is displayed.
CLEAR
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appear when the 941X needs to know more about
to answer “NO.” All other keys, including the function
ENTER
to answer
Page 20 2 — Using the Controls
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3
Basic Navigation
Displaying Position, Heading & Speed 22
Position Plotter 22
Using GPS 25
Using Loran 30
Using Phantom Loran 32
HIS SECTION describes the most basic—yet important—navigation function available in the Northstar
941X: determining your position.
Position coordinates may be determined from the GPS sat-
ellite system, or you may display loran coordinates if you
have connected a loran receiver.
For those who no longer have a loran r eceiver, but wish to
view their posit ion in loran TDs , the 941 X can conver t GPS
coordinates into Phantom Loran coordinates.
Rev. D 3 — Basic Navigation
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Displaying
Position,
Heading &
Speed
O DISPLAY the coordinates of your current position, simply press
T
the button marked
position coordinates at the top, and your Course-Over-Ground (COG)
and Speed-Over-Ground (SOG) at the bottom. (If you see the
screen displayed instead of your position coordinates, just press the
POSITION
GPS position coordinates are displayed as latitude and longitude. You
may choose to display loran coordinates instead, as described below.
(Loran coordinates may be obtained fr om a loran receiver connected to
the 941X, or may be calculated by th e 941X from the GPS posit ion coordinates.)
button again).
POSITION
. A screen is displayed showing your
PLOT
Positio n Plo tter
Page 22 3 — Basic Navigation
The position plotter screen is a “ nort h-up ” di spla y, a nd pr ovid es an over all view of the surrounding area and all nearby waypoints. Press the
POSITION
route (if any), your track history, and any nearby waypoints and avoidance points.
A maximum of 30 local waypoints can be displayed on the plotter screen
at one time.
key to show your position plotted relative to your current
3 — Basic Navigation Rev. D
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