North s ta r 941X
Referen ce Ma n u a l
S O F T W A R E V E R S I O N 2 . 0 5
30 SUDBURY ROAD
ACTON, MASSACHUSETTS 01720
(508) 897-6600
Copyright 1994, 1995, 1996 Northstar Technologies
P/ N GM1100 Doc. Rev D
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WARRANTY
Northstar Technologies, a Division of CMC Electronics, Inc., warrantees its products
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 mainframes 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 consequential 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.
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IMPORTANT NOTICE
Although Northstar products are designed to be very useful navigation tools, they
are not substitutes for good seamanship. The prudent navigator should never rely on
any single device as the sole source of navigation guidance. Exercise caution and
good judgment whenever underway.
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CONTENTS
!
!
The 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
1
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
2
3
Basic Navigation
Displaying Position, Heading & Speed ......................22
Position Plotter ...........................................................22
Using GPS ................................................................... 25
Using DGPS ................................................................26
Using Loran ................................................................30
Using Phantom Loran ................................................32
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Creating Waypoints and
Routes
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
4
Waypoint & Route Navigation
Quick-Start Waypoint................................................. 54
Navigating to Waypoints ............................................ 55
Navigating Along Routes............................................ 59
Restarting the Course Line......................................... 61
5
6
The NAV LOG Function
What NAVLOG Does ..................................................64
Logging Your Trip....................................................... 65
Changing Your Trip .................................................... 65
Adding Waypoints to the Trip ....................................66
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Other Special Functions
Alarms .........................................................................68
Screen Backlighting .....................................................71
TideTrack™..................................................................71
Internal Differential Beacon Receiver ....................... 74
7
8
Customizing 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
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
9
Appendix (Specifications) ........................................ 129
Glossary..................................................................... 135
Index ......................................................................... 138
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Figures
FIGURE 1—MAX. POSITION VARIANCES WITH UNCORRECTED GPS.... 8
FIGURE 2—YOKE MOUNT DRILLING DIMENSIONS........................... 102
FIGURE 3—REAR CONNECTORS ...................................................... 103
FIGURE 4—941X GPS-ONLY ANTENNA (AN145 & AN150).......... 105
FIGURE 5—941X COMBO GPS/DGPS ANTENNA (AN190)............. 105
FIGURE 6—STRIPPING THE COAX CABLE JACKET............................ 107
FIGURE 7—FLARED CABLE BRAID .................................................. 108
FIGURE 8—COMPLETED BNC CONNECTOR .................................... 108
FIGURE 9—ACU ASSEMBLY ........................................................... 110
FIGURE 10—PL 259 (UHF) CONNECTOR........................................ 111
FIGURE 12—200 PPNM OUTPUT BLOCK DIAGRAM........................ 115
FIGURE 13—941X DIMENSIONS ...................................................... 132
Tables
TABLE 2—INTERFACE CONNECTOR PINS ........................................ 114
TABLE 3—PORT SETUP OPTIONS..................................................... 116
TABLE 4—NMEA 0183 SENTENCE IDENTIFIERS............................. 120
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1
Introducing the Northstar 941X
Introduction
Upon First Start-up
Using This Manual
Features
2
2
3
4
5
5
9
9
Functions
Comparing GPS and Loran
Mounting
Special Functions
The Display Screen 10
Interfacing Capability 11
his section introduces you to the Northstar 941X navi-
gator, 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
Page 1
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HE NORTHSTAR 941X combines 12-channel GPS navigation with
In trod u ction
TDifferential GPS capability, a high-definition display, loran compati-
bility, 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 ad-
vanced system gives you even greater accuracy by accepting Differential
GPS signal “corrections” from shore-based transmitters (called “bea-
cons”), and using them to display position fixes as accurate as 2-5 me-
ters. 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).
When you turn your 941X on for the very first time, you may be greeted
with a flashing exclamation point symbol in the lower right portion of the
GPS POSITION screen, and the word ACQUIRE or SKY SEARCH in
the status box at the top. The flashing exclamation point simply means
that an alarm message is present and waiting for your acknowledgment.
Up on Firs t
Start-u p
To see the message, press the STAR key once. The ALARMS AND
BACKLIGHT screen will be displayed.
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1 — Introduction
Rev. D
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The alarm message NO GPS POSITION FIX, along with its time and
date, are shown in the RECENT ALARMS box. The word NEW in the
upper right corner of the box indicates that this is a previously unac-
knowledged 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 in-
formation 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 shipped to customers lo-
cated more than several hundred miles from the Northstar factory, and
only the first time the 941X is turned on after being installed.)
Press the CLEAR ALARM menu key to the right of the display screen to
acknowledge and clear the message. Press the POSITION key below the
left of the screen to return to the main GPS POSITION screen. The 941X
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 naviga-
tor, 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 the 941X’s various functions in
a format helpful to quick learning and safe operation.
Us ing This
Manual
The sections in this manual are grouped by related functions, beginning
with an overview of basic control panel layout and function commands,
and gradually progressing to more advanced waypoint and route naviga-
tion operations. Sample screen images are used throughout to help il-
lustrate what the 941X display 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 quick-
reference for locating less-frequently-used operations.
"
Rev. D
1 — Introduction
Page 3
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Upon using the 941X, you’ll see that you can actually learn to operate the
system’s various features without constant referral to this manual. After
you’ve read through it once, you won't have to refer to it very often again.
Featu res
Since the 941X anticipates your most frequent requests for navigation
information, accessing most functions requires 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.
•
•
accurate, worldwide position data in any weather, 24 hours a day
GPS feat u res
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
n avig at ion
feat u res
built-in plotter shows:
1) your position relative to nearby waypoints;
2) your recent 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
wayp oin t s an d
rou t es
displays waypoints:
1) in alphabetical order
2) in order of distance from your present position
3) saved with the
button
SAVE
4) stored as avoidance points
•
plots position of:
1) nearby waypoints
2) routes
3) avoidance areas
Page 4
1 — Introduction
Rev. D
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Five keys on the 941X instantly select the most commonly used func-
tions, as described below:
Fu n ction s
POSITION displays position coordinates as
1) GPS lat/ lon coordinates
2) loran TDs, if you have a loran receiver interfaced to the unit
3) or calculated “Phantom Loran ” TDs if you don't.
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 shows how to steer precisely along a course line to your current
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.
(
) (The STAR key) displays alarm conditions and tide information,
and accesses setup functions for customizing the operation and displays
of your 941X, including screen brightness.
WAYPTS/ ROUTES lets you enter or access waypoints and routes for
navigation.
NAV LOG displays the progress of your current navigation plan (today’s
trip) and lets you modify it.
In addition to these function keys, the SAVE/ MOB key instantly saves
your position as a waypoint, and provides a Man Overboard function for
returning to the saved point.
Five MENU KEYS on the right edge of the display are used to select be-
tween specific choices displayed on the screen.
The nation’s GPS system has received much publicity, often described as
providing the ultimate in navigation accuracy for all applications. Its
major advantage over all other commercially-available navigation sys-
Com p aring GPS
an d Loran
tems, including loran, is its all-weather, worldwide availability and
ab-
. (
solute accuracy Absolute accuracy
refers to the ability of a navigation
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
Page 5
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from a chart or other reference.
refers to the ability
Repeatable accuracy
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 spares) literally encircles
the earth with navigation information. GPS is offered in two forms: for
military users and for civil users.
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
s elect ive
availab ilit y
GPS signals that only U.S. forces could bypass. Called
Selective Avail-
(or SA), it involves a complex formula of data encryption that can
ability
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 me-
ters (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 be-
yond 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 8-
20 meter accuracy for navigating harbors. It was then that a system of
GPS an d DGPS
was developed by the Coast Guard that enabled
differential corrections
them to effectively circumvent SA’s built-in errors.
These differential corrections are generated by fixed “reference stations”
and broadcast by marine radiobeacons over a relatively limited area—
usually a maximum broadcast radius of 250 miles—to Differential-
capable 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
Rev. D
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“beacons,” the transmitters are being situated at various locations along
the U.S. coastline and Great Lakes, most of which are former marine ra-
diobeacon sites.)
With DGPS, navigators are guaranteed position accuracy on the order of
50% of the time, and to 10 meters 95% of the time (usually,
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 elec-
tronic plotter, DGPS corrections improve the steadiness of your dis-
played 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 integ-
rity monitor instructs the DGPS receiver not to use data from the satel-
lite in question.
Loran, on the other hand, can still outperform non-differential GPS—
loran
when SA is in effect—in
. Though susceptible to
repeatable accuracy
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
accuracy was
repeatable
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
(100 meters) of your intended destination. Obviously,
300 feet
uncorrected GPS—with variations of up to 300 feet in displayed posi-
tion—wouldn’t be much help in getting you through a narrow channel.
Since most loran chains were configured for optimum coastline naviga-
tion, it’s easy to see why loran’s
accuracy has served harbor-
repeatable
masters and fishermen well for the last 25 years.
Rev. D
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Page 7
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Loran, however, isn’t as proficient as GPS in
, or visit-
absolute accuracy
ing a spot for the first time. Since it transmits at a relatively low fre-
quency (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 trans-
mitters. It’s in these two areas that GPS consistently excels when it
comes to
accuracy.
absolute
Even with SA, GPS provides an
accuracy of around 300 feet
absolute
nearly everywhere in the world, under virtually any conditions. With a
“constellation” of satellites orbiting the earth and transmitting their po-
sition data on an extremely high frequency (1.575 GigaHertz, or 1.5
bil-
cycles per second), GPS is impervious to weather and your location
lion
on the surface of the earth. You can receive position fixes at any time,
anywhere, in any weather. This far surpasses the accuracy that
absolute
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
accu-
repeatable
racy to return to within a boat length of a lobster trap or a buoy, time af-
ter 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
300’
You could be
anywhere within
the circle, 95% of
the time.
300’
Figure 1—Max. Position Variances with Uncorrected GPS
Page 8
1 — Introduction
Rev. D
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If you need a higher level of accuracy than what basic GPS provides,
there are two choices available to you:
g et t in g m ore
accu racy
1. Use
by installing a Northstar internal differential
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 (repeat-
able and absolute) 95% of the time. See “Using GPS” on page 25 for
more information.
2. Interface your
to your 941X (provided the loran has
loran receiver
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 world-
connector pin wiring guide.
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 the vessel to minimize the ef-
fects of pitch and roll, and where it has a clear view of the entire sky. The
Beacon Receiver antenna (if installed) should be mounted fairly high,
like a loran antenna. Refer to “Mounting the 941X,” on page 100, for de-
tails.
Mounting
The following functions are unique to the 941X; you may want to read
about them in detail before using them.
Sp ecial
Fu n ction s
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 conver-
sion 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
loran TDs
Rev. D
1 — Introduction
Page 9
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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.
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.
p lot t er fu n ct ion s
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 choose. See page 71 for more information on
using TideTrack.
Tid eTrack™
The Liquid Crystal Display (LCD) and all controls are lighted for night-
time use. The display is easily readable under all conditions, from full
sunlight to total darkness. Anti-reflection 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.
Th e Dis p lay
Screen
To adjust the brightness, press the STAR key (
) and use the BRIGHT
and DIM menu keys to set the desired illumination. Contrast is con-
trolled by the ARROW key to the left of the screen.
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 the
window. Use a small amount of window cleaner or alcohol to dissolve
clean in g t h e
s creen
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1 — Introduction
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any oil or grease on the screen. Whenever possible, avoid touching the
window with your fingers, as natural oils from your hand will temporar-
ily degrade the characteristics of the window and cause your fingerprints
to appear as bright reflections. These will disappear when the screen is
cleaned as described above.
CLEANING HINT
Pre-packaged moist towellettes (especially those containing a
small amount of alcohol) are excellent for cleaning the display
window. You might wish to keep a supply on hand to wipe off
fingerprints and other smudges.
The 941X contains two independent output ports for driving NMEA-
compatible 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 way-
point/ route or software program loading from a PC. The 941X can be
interfaced to a wide variety of devices, including autopilots, plotters, ra-
dars, etc. Refer to “Interfacing the 941X,” beginning on page 112, for
more information.
Interfacing
Cap ab ility
Rev. D
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Page 12
1 — Introduction
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2
Us in g th e Con trols
POWER Key 14
CONTRAST Key 14
SAVE/ MOB Key 15
Function Keys 16
Menu Keys
Cursor Keys
Keypad
17
17
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 using its various functions.
Rev. D
2 — Using the Controls
Page 13
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HE MAJOR FUNCTIONS of each of the 941X's controls are de-
Tscribed in this section.
Press the POWER switch briefly to turn on the 941X. The unit displays a
special startup screen that includes an owner-identification message
which you may customize to aid in theft-prevention. Next, the 941X dis-
plays the results of the internal self-tests that are automatically run each
time the unit is turned on. Finally, navigation data is displayed.
POWER Key
If any of the six major components of the 941X fails the self-test, the no-
tification SYSTEM TEST: FAILED will remain on the screen until you
acknowledge it with the press of any function key (located below the dis-
play screen). Return the 941X to the factory for service.
To turn the 941X off, press the POWER switch and hold it in for at least
one full second until the unit turns off.
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 conditions. Pressing the upper contrast
arrow darkens the screen, and pressing the lower arrow lightens it. Ad-
just the screen for the best contrast as seen from your normal operating
location.
CONTRAST Key
Page 14
2 — Using the Controls
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The SAVE/ MOB key is used to save your current position as a waypoint.
It does this in either of two ways, depending on whether you press the
key briefly, or press and hold it.
SAVE/ MOB Key
Press the SAVE/ MOB button briefly to simply store your position. This
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.
s avin g a
wayp oin t
The waypoint’s 3-digit number will “wrap around,” or revert, to –S001–
when the 941X has reached the limit you set using the MAX SAVED
WPT # function under DISPLAY OPTIONS (see page 80).
Press and hold the SAVE/ MOB button for three seconds to enter “Man
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 dis-
play, showing your position and the MOB location. The MOB location
immediately becomes your current waypoint, with new bearing and dis-
tance information displayed on the right-hand side of the screen.
Man Overb oard
feat u re
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 se-
verity 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
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To leave MOB mode and return to normal navigation, press SAVE/ MOB
for at least three seconds.
The five function keys located below the display screen control what the
941X is doing. Any function key may be pressed at any time to display
the information you need to see.
Fu n ction Keys
The POSITION key displays your position coordinates, or displays a
plotter screen to show your position graphically, relative to nearby way-
points and your track history. Course-Over-Ground and Speed-Over-
Ground are displayed at the bottom of the screens.
POSITION key
“Where am I?
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 from its GPS coordi-
nates
The STEER key shows how to steer to a waypoint you have designated. A
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 available. Press STEER once to see
the version you were last using. Press it again to see the other version.
STEER key
“How do I
get to my
waypoint?”
The STAR key (
) has several functions. The first press displays any
STAR key
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 displays a menu of setup and cus-
tomization functions used whenever you wish to change the way the
941X works for you.
The WAYPTS/ ROUTES key allows you to enter waypoints and routes,
access a library of waypoints and routes that you have entered previ-
ously, or specify where you want to navigate to.
WAYPTS an d
ROUTES key
“Where do I
want to go?”
See Sections 4 and 5 for waypoint and route information.
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The NAV LOG key displays the waypoints you have passed, and allows
you to change those ahead of you. See “What NAV LOG Does,” on page
64, for more information.
NAV LOG key
“How am I
doing?”
The five round MENU keys on the right side of the display screen are
used for different purposes depending on what function is currently be-
ing used or displayed. The function of each key is labeled on the screen,
and pressing the key performs the displayed function.
Menu Keys
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 way-
point’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 field.
Cu rs or Keys
The 12-button alphanumeric keypad is used for entering numbers, letters
or special characters for waypoint coordinates, names, etc.
Keyp ad
When the 941X is expecting you to enter numbers only, such as for way-
point coordinates, the keypad keys enter one digit, 0-9, with each key-
press. The flashing cursor moves automatically to the next digit position.
en t erin g
n u m b ers
For entries such as latitude and longitude—where the digits must be en-
tered into specific character positions—the cursor starts on the left side
of the field and characters are entered left to right into their correct po-
sitions.
For other numeric entries such as distances—where a number of variable
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 to
clear the entire number and re-enter it, or you can press the left-arrow
cursor key to reenter particular digits, one at a time.
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.
en t erin g let t ers
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 brings 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 ar-
row symbol on the cursor key.
"
The keypad also contains CLEAR and ENTER keys for erasing or enter-
ing data that has been typed on the keypad. Pressing the ENTER key is
always the last step when entering or changing data, or acknowledging
an action. The CLEAR key removes any data you typed before you press
ENTER, and sets the field to all blanks or restores it to its value before
you changed it.
CLEAR an d
ENTER keys
Occasionally, the 941X needs to inform you of something or ask permis-
sion to do something. When this happens, a special information or ques-
tion window appears on the display. The window contains an
Sp ecial Dis p lay
Win d ows
INFO
exclamation point (“!”), an “ ” label, or a large question mark (“?
”),
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 bottom-
right portion of the display.
alarm m es s ag es
Press the STAR key once to show the alarm condition on the ALARMS &
BACKLIGHT screen. Press the CLEAR ALARM menu key to acknowl-
edge and clear the message.
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are displayed while you are entering data or using
Information windows
in form at ion
win d ows
control functions. They give you extra details pertaining to what is about
to happen, or let you acknowledge a command. Information windows
INFO”
always appear with the word “
in a small box.
appear when the 941X needs to know more about
Question windows
q u es t ion
win d ows
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 ENTER to answer
“YES,” or CLEAR to answer “NO.” All other keys, including the function
keys, are inactive when a question window is displayed.
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3
Bas ic Navig ation
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 impor-
tant—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 receiver, but wish to
view their position in loran TDs, the 941X can convert GPS
coordinates into Phantom Loran coordinates.
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O DISPLAY the coordinates of your current position, simply press
Dis p laying
Pos ition ,
Head in g &
Tthe button marked POSITION. A screen is displayed showing your
position coordinates at the top, and your Course-Over-Ground (COG)
and Speed-Over-Ground (SOG) at the bottom. (If you see the PLOT
Sp eed screen displayed instead of your position coordinates, just press the
POSITION button again).
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 from a loran receiver connected to
the 941X, or may be calculated by the 941X from the GPS position coor-
dinates.)
The position plotter screen is a “north-up” display, and provides an over-
Pos ition Plotter
all view of the surrounding area and all nearby waypoints. Press the
POSITION key to show your position plotted relative to your current
route (if any), your track history, and any nearby waypoints and avoid-
ance points.
A maximum of 30 local waypoints can be displayed on the plotter screen
at one time.
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The image of your boat displayed on the screen points in the direction of
your Course-Over-Ground. Remember, this direction may be different
from your heading. The boat image shows your actual direction of travel
over the bottom, not the direction your boat is headed. If your boat is not
moving, the Course-Over-Ground cannot be determined by the 941X,
and the direction of the boat on the screen has no meaning.
Avoidance areas (waypoints for which a warning radius has been speci-
fied) are shown as a circle surrounding the waypoint.
Your present Speed-Over-Ground (SOG) and Course-Over-Ground
(COG) are displayed at the bottom of the screen, along with the chart
scale. The chart scale is the distance from the top edge to the bottom
edge of the plot.
NOTE:
The plotter screen can be used to steer by when the objective is
simply to get to the waypoint without needing to remain pre-
cisely on the designated course line.
Press the ZOOM IN menu key to zoom in for a closer look at the area in
the center of the screen. Press the ZOOM OUT menu key to zoom out to
see more area. Each press of the IN or OUT key approximately halves or
doubles the chart scale, respectively.
zoom in g
The maximum zoom-in screen displays an area that is approximately ¼ -
mile from the top edge to the bottom, while maximum zoom-out shows
you an area that is up to 128 miles, top to bottom.
Press the CENTER menu key at any time to move the plotted area so
cen t erin g t h e
p lot
that your boat is at the center of the screen.
If you wander off your intended course line, and you want to navigate
directly to the waypoint rather than returning to the original course line,
press the RESTART menu key, then ENTER. A new course line will be
computed and displayed, running from your present position to the next
waypoint.
cou rs e res t art
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To set up the parameters for the display of data on the plotter screen,
p lot t er op t ion s
press the OPTIONS menu key. The following screen is displayed:
The plotter control menu allows you to change the following items:
•
The plotter scale at and above which waypoint names will not be
displayed on the plotter screen
•
•
•
•
Whether local waypoints are displayed on the screen
How often your position is recorded on the screen
Whether your track history is displayed on the screen
Whether a lat/ lon grid is displayed on the screen
To change any one of these, use the up and down cursor keys to move the
arrow to the item you want to change, and press the EDIT menu key.
This will cause a large cursor to flash on the field, indicating you should
use the up and down cursor keys to select the option you want. Press
ENTER when done, or CLEAR to restore the field to its original value.
"
The 941X can store up to 900 points in its track, so the maximum length
of the track depends on how often points are stored.
You may choose to store track points every second, with a maximum
length of 15 minutes, or every two minutes for a maximum length of 30
hours, or a number of settings in between.
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You may also choose to freeze the track, so that no more points will be
stored and the track will remain unchanged.
Pressing the CLEAR TRACK menu key clears the track history displayed
on the screen.
Press the RETURN menu key to go back to the plotter screen.
Your 941X contains an internal GPS receiver which is used as the pri-
mary source of position data.
Us ing GPS
GPS data is displayed directly on the GPS POSITION screen.
lat / lon
coord in at es
The GPS position screen displays your latitude and longitude in large
digits near the top of the screen. If GPS data is not available, dashes are
displayed in place of the numbers.
You can display lat/ lon as either degrees, minutes and seconds,
or as degrees, minutes and thousandths of minutes. See
“Display Options,” on page 78, to select one or the other.
The time of day and today’s day and date (obtained from the GPS satel-
lites) are displayed at the bottom of the screen.
t im e of d ay
Near the bottom of the screen, your Speed-Over-Ground and Course-
Over-Ground are displayed in large digits.
s p eed an d
cou rs e
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NOTE
The 941X’s speed and course readings are the result of instan-
taneous measurements derived from satellite signals. GPS
speed is updated every second. However, you may average
these readings by changing the “GPS speed averaging” value
(see page 87).
In the center of the screen, the name of the datum currently in use is dis-
played. The datum describes the reference of the chart you are currently
using (the reference datum used is indicated on each chart). Applying the
datum corrects for any position differences between your chart and the
GPS coordinate system. See “Geodetic Datum,” on page 94, for more in-
formation on selecting the datum for your area.
d at u m
NOTE
When using differential GPS (DGPS) as your navigation
source, your position, as displayed by the 941X, may actually
exceed the accuracy of some charts.
At the top center of the position screen is a brief status summary of the
GPS receiver. The following table shows the various status messages the
941X may display, along with their meanings.
s t at u s s u m m ary
Message
Meaning
trying to acquire satellites
ACQUIRE
SKY SEARCH
TRACKING
2D NAV
3D NAV
POOR FIX
COMM FAIL
searching for satellites with no previous information
satellites have been acquired; almost ready to navigate
navigating with 3 satellites in 2-D mode
navigating with 4 or more satellites in 3-D mode
tracking satellites with poor geometry/accuracy
communication link to GPS sensor has failed—unit
needs repair
In the upper right corner of the GPS POSITION screen is an indicator
that shows whether Differential GPS (DGPS) corrections are in use. If
your installation includes an optional Northstar internal differential GPS
receiver, or other external source of differential corrections, navigational
accuracy will be significantly improved when this indicator is present.
Us ing DGPS
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For further information on operating in DGPS mode, refer to “Internal
Differential Beacon Receiver,” on page 74.
With DGPS active, you will often see position measurements accurate to
about 2-5 meters, speed measurements accurate to about 0.1 knot, and
Course-Over-Ground measurements accurate to about 0.5 degree. DGPS
corrections remove the errors caused by Selective Availability (SA) and
the atmosphere, and provide an accuracy exceeding that obtained by
military users of the GPS system. If the DGPS indicator is displayed, you
have this higher level of accuracy. For the POSITION and STEERING
screens, the DGPS indicator is a large letter “D.” For the plotter screen,
the DGPS indicator is the symbol DGPS.
To display more information about signals received from the GPS satel-
lites, press the SATS menu key on the GPS position screen. A screen is
displayed showing the received Signal-to-Noise Ratio for each satellite,
and a map indicating where the satellites are currently located in the sky
(the 12-channel GPS SATS screen is shown on the next page). Satellites
s at ellit e s t at u s
are identified by their
U.S. government.
number, a two-digit number assigned by the
PRN
The center of the satellite map represents the center of the sky, and the
outer (or last) ring is the horizon. The view is looking down from above,
with East to your right and West to your left.
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NOTE
On five-channel 941Xs, the last bar at the bottom of the screen
will sometimes “jump” around once per second as the 941X
receiver sequences among other satellites.
The following GPS data is also displayed:
ACCURACY: The estimated accuracy of the GPS system to be
expected at the current time. Your position readings should be more ac-
curate than this estimate 95% of the time.
HDOP: This is a technical measure of the “quality” of your fix.
HDOP (Horizontal Dilution of Precision) can range from an ideal value
of 1, up to 10 or more. Any value less than 2 indicates excellent perform-
ance. HDOP is calculated from the satellites’ current positions, and is not
based on actual received signals. You will usually see an HDOP value
displayed immediately after the unit is turned on, and before it is ready
to navigate.
Press the RETURN menu key to return to the previous screen.
To display more information about DGPS corrections that are being re-
ceived, press the DGPS menu key on the GPS position screen. A screen is
displayed showing the DGPS beacon transmitter currently in use. The
upper part of the screen shows the beacon’s name and position, the fre-
quency of the transmitter, and the baud rate of the transmitted data.
DGPS s t at u s
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The lower part of the screen shows three bar graphs:
1. SNR The Signal to Noise Ratio (SNR) is a good overall measure of
overall signal quality, and should be as high as possible. Values of
15 and higher are preferred, while anything below 10 could indicate
poor reception.
2. SIGNAL The actual strength of the received signal—should be as
high as possible. Varies with distance from beacon transmitter.
3. NOISE Noise level measures the “static” caused by lightning and
other atmospheric effects, and should be low for best results. See
“DGPS antenna mounting” on page 112, for further details.
NOISE LEVEL VALUE
200 or less
MEANING
excellent
1,000 – 3,000
5,000 – 10,000
typical at night
thunderstorm
At the bottom of the screen a summary of DGPS operation is displayed.
You may see one of the following messages:
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MESSAGE
MEANING
No DGPS corrections have been received
within the DGPS DATA TIMEOUT limit set
in RECEIVER OPTIONS (default is 1 min-
ute), and the navigator has returned to non-
differential operation. See “GPS data time-
out” on page 89 for details.
OLD CORRECTIONS
A beacon receiver is not installed.
The beacon transmitter reports it has prob-
lems.
NOT INSTALLED
UNHEALTHY
BEACON
Data received from satellites cannot be re-
lied upon.
UNHEALTHY SATS
1) The GPS receiver cannot operate in
DGPS mode until it has received ephemeris
data from the satellites; or 2) the receiver
does not have a GPS fix yet.
DGPS corrections are being received and
used.
ACQUIRING SATS
DGPS IN USE/ OK
DGPS signal quality information for the 941X is available from the op-
tional internal beacon receiver, or from an optional external Northstar
beacon receiver. Other brands of beacon receivers may supply DGPS cor-
rections but omit the additional signal information shown on the 941X’s
screen.
Press the RETURN menu key to return to the previous screen.
If you have a loran receiver connected to your 941X, you can navigate
using loran coordinates as well as GPS. Just select loran as the source of
navigation data, as described below, and you’re on your way.
Us ing Loran
s elect in g loran
"
To display loran TD coordinates from a loran receiver interfaced to the
941X, first select loran as the navigation source, as described below.
1. Press the STAR key until the USER CUSTOMIZATION screen is
displayed.
2. Press the NAVIGATION OPTIONS menu key. The NAVIGATION
SOURCE line will be designated by the cursor arrow.
3. Press the EDIT menu key. The cursor will begin flashing.
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4. Press the up and down cursor arrow keys to display EXTERNAL
LRN as the position source. If you change your mind, press CLEAR
to restore the original setting; otherwise, press ENTER, then the
RETURN menu key.
The loran display screen looks like this:
loran TDs
Press the L/ L TDS menu key several times to select either the particular
pair of TDs you wish to use, or the loran-derived latitude/ longitude.
NOTE
In order to display loran position coordinates on the 941X
from an externally-connected loran receiver, the loran must
support the standard NMEA 0183 “RMA” output data sentence
structure. Without this output capability, the 941X will not re-
ceive position data from the loran. For best results, connect a
Northstar 800 series loran to the 941X, using the 800’s
“PRINTER 3” output format. See “connecting to a Northstar
800 series loran” on page 123.
The four-digit loran Group Repetition Interval (GRI) is changed using
the SET GRI menu key on the LORAN POSITION screen. You must set
this to correctly match the GRI being used by your loran receiver for the
941X to accurately convert the loran’s TDs to latitude/ longitude position
fixes.
loran GRI
Loran warning indicators obtained from any Northstar 800 series loran
receiver are displayed to the right of each TD. These are:
loran warn in g s
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INDICATOR
SNR
MEANING
Signal-to-Noise Ratio is low—use caution
Coast Guard is transmitting a blink signal indicat-
ing a probable transmitter problem
BLNK
the receiver has detected a possible cycle slip
the receiver has locked onto the loran track point.
This is not a warning indicator but an indication of
normal performance.
CYC
LOCK
Note: These indicators are available only from Northstar 800 lorans.
The “L/ L” indicator to the left of a TD designates it as one of the two TDs
that the loran receiver has chosen to use to calculate latitude and longi-
tude.
The “F/ L” indicator to the left of a TD indicates that it has been forced by
the user to be used to calculate lat/ lon.
To check the quality of signals being received by your loran, press the
LORAN INFO menu key from the LORAN POSITION screen. The Sig-
nal-to-Noise Ratio for each loran transmitting station is displayed
graphically. Press RETURN to go back to the loran position screen.
loran in fo
To temporarily display GPS coordinates and signal status, press the
CHECK GPS menu key. The unit continues to navigate using loran, and
will display loran data the next time you return to the position screen.
ch eckin g GPS
s t at u s
To return to GPS signals for navigation, repeat the steps shown above for
selecting loran, except specify GPS instead of loran.
ret u rn in g t o GPS
n avig at ion
The 941X’s Phantom Loran feature is designed for those users who have
compiled lists of fishing spots or other locations as loran TDs, and are
now using the 941X as a GPS-only navigator. The 941X will mathemati-
cally convert GPS lat/ lon coordinates to loran TDs, enabling you to dis-
play your position as TDs.
Us in g Ph an tom
Loran
The 941X may be used to simulate full operation of a loran receiver. Po-
sition coordinates may be displayed as TDs, and all navigation functions
may be used as if the unit were actually receiving loran signals. Remem
Ph an t om Loran
op erat ion
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ber, however, that these calculated TDs will not match exactly the posi-
tions of previously recorded TD coordinates obtained directly from ac-
tual loran signals. In most areas, errors should not exceed 0.2
microsecond. However, larger errors are possible in areas for which the
941X does not contain accurate, factory-programmed ASF correction
points.
To display Phantom Loran TDs as position coordinates, first select
Phantom Loran as the position source, as described below.
s elect in g
Ph an t om Loran
1. Press the STAR key until the USER CUSTOMIZATION screen is
"
displayed.
2. Press the NAVIGATION OPTIONS menu key. THE NAVI-
GATION SOURCE line will be designated.
3. Press the EDIT menu key.
4. Press the up or down arrow keys to display PHANTOM LRN as the
position source.
5. Press ENTER, then the RETURN menu key.
6. To view your position in Phantom Loran coordinates, press
POSITION.
The Phantom Loran display screen looks like this:
Ph an t om Loran
TDs
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Press the L/ L TDS menu key several times to select the particular pair of
ch oos in g L/ L or
TDs
TDs you wish to use or to display GPS latitude/ longitude.
Press the SET GRI menu key to change the GRI to be used in calculating
the displayed TDs. Press the up and down cursor keys to display the
available GRIs one at a time. When the GRI is correct, press ENTER.
Ph an t om Loran
GRI
Press the SAT INFO menu key to check on the received GPS satellite
ch eckin g GPS
s t at u s
status, as described on page 27.
Press the DGPS INFO menu button to display the current status of the
beacon receiver, including SNR, SIGNAL and NOISE values (as previ-
ously described on page 29). Press RETURN when you wish to go back to
the PHANTOM LORAN position screen.
ch eckin g DGPS
s t at u s
The
large
letter
displayed in the upper right corner of
DGPS
correct ion s
the display indicates differential GPS corrections are being received and
used to improve the accuracy of the received data.
To return to GPS signals for navigation, repeat the steps shown above for
ret u rn in g t o GPS
n avig at ion
selecting loran, except specify GPS instead of Phantom Loran.
See “Navigating to Waypoints,” beginning on page 55, to learn how to
navigate to loran, Phantom loran, or GPS coordinates.
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4
Creatin g Wayp oin ts an d
Rou tes
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
In this section, we’ll learn how to create waypoints, use
them to form routes, and change them as necessary.
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Before we move on to the sections describing how to enter waypoints and
routes into the 941X’s memory, let’s take a break and review the methods
for entering data into the unit.
En terin g Data
Some screens, such as coordinate entry screens, allow entry of numbers
only. Others, such as waypoint names, allow entry of letters, digits and
punctuation characters.
A typical entry screen will have several items of data displayed. First,
choose the item you wish to change by pressing the up or down cursor
arrow key to move the flashing cursor to that item.
"
The flashing cursor indicates which character position will be written
into. Use the left and right cursor arrows to move the flashing cursor to
the next character you want to enter.
Use the up and down arrows to move to the next line you want to enter.
When the entire screen is correct, press the ENTER key. The 941X will
accept the full screen of data and store it in memory.
To enter numbers, simply press the digits of the keypad. The flashing
cursor automatically moves to the next character.
en t erin g
n u m b ers
You can use the arrow keys to “back up” and correct any mis-
takes you might have made.
Many items, such as waypoint names, accept letters as well as numbers.
Each key of the keypad is labeled with up to four characters. Find the key
with the desired character, and press that key one or more times to dis-
play the character. When the character has been selected, use the right
arrow cursor key to move the cursor to the next character position. Press
ENTER when all the characters are correct.
en t erin g let t ers
Here are some of the things you can do with waypoints using your 941X:
1. Navigate to a point in one step (a “quick start” waypoint)
2. Enter waypoints into the 941X’s memory for later use
3. Navigate to these waypoints
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4. String these waypoints together to form routes
5. Follow these routes
6. Edit or erase waypoints or routes
7. Plot waypoints or routes
8. Transfer waypoints and routes from the 941X to a personal com-
puter, and back again.
To enter waypoints, press the WAYPTS/ ROUTES key. Press the
WAYPT LIST menu key and then the ADD menu key. A screen similar
to the following is displayed:
Creatin g
Wayp oin ts
To store a waypoint permanently in the 941X's memory, first assign it a
name. The name can be from 1 to 6 characters long, and it must differ by
at least one character from any other waypoint name in the unit's mem-
ory.
Enter the desired waypoint name. If you wish, you may also enter up to
16 characters of descriptive information for the waypoint on the line be-
low the name (the description is optional).
If the name you chose is already in use in the unit’s memory, a
message is displayed, indicating you cannot use that name.
You can either erase the old waypoint, if it is no longer needed,
or choose a different name for the new waypoint. The name of
the new waypoint need only be different from the existing
waypoint by one character in order to be accepted as a valid
name.
Rev. D
4 — Creating Waypoints and Routes
Page 37
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Waypoint coordinates can be entered as lat/ lon coordinates, loran TDs,
or as distance and bearing from your present location or from any way-
point in the 941X’s memory.
wayp oin t
coord in at es
To change the coordinate type from what is currently displayed, press
"
the COORD TYPE menu key until you see the option you want.
Enter the waypoint coordinates as previously described on page 36. If
you make a mistake, press CLR to erase any characters from the line and
start over; otherwise, press ENTER when the screen is correct.
If you are entering coordinates as distance and bearing, the 941X nor-
mally asks for these coordinates relative to your current position, known
as “–HERE–.”
To select an entirely different location from which distance and bearing
are to be measured, such as an existing waypoint, press the FROM menu
key. A waypoint list is displayed. You can press the NEXT LIST or
COORD OPTION menu keys to help select the waypoint.
Use the up and down cursor arrow keys to point to the desired waypoint.
Press the ENTER key to designate this waypoint and return to the previ-
ous screen. If you wish instead to use your present position as the refer-
ence point, press the FROM ‘HERE’ menu key on the ‘FROM’
POSITION screen.
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4 — Creating Waypoints and Routes
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avoid an ce area
If this new waypoint is to be used as the center of an
, en-
avoidance area
ter the warning radius at the bottom of the screen in the WARN RADIUS
box. If no radius is entered, the point will be treated as a regular way-
point, and not as an avoidance area.
You may designate new or existing waypoints as avoidance areas. Avoid-
ance areas are depicted on the PLOT screen as waypoints with circles
around them. In addition, an alarm will be given both as an audio beep
and a flashing exclamation point on the screen, if you should enter and
avoidance area.
Avoid ance
Areas
The 941X will display each avoidance area as a circle the size of the
warning radius you entered. For new waypoints, enter a distance in the
WARN RADIUS box at the bottom of the NEW WAYPT screen. For ex-
isting waypoints, use the EDIT WAYPOINT function to access the way-
point coordinate screen, then enter the warning radius. Be sure to
include a little extra distance around the hazard so that you will have
time to respond by turning or stopping after you hear the alarm.
Rev. D
4 — Creating Waypoints and Routes
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As a precaution, once you have designated a waypoint as an avoidance
area, the 941X does not allow you to navigate to it.
Once you have designated a waypoint as an avoidance area, the 941X will
alert you upon penetration of that area.
avoid an ce area
alarm
To set the audible avoidance area alert feature:
"
1. Press the STAR key once to display the ALARMS & BACKLIGHT
screen.
2. Be sure that the cursor arrow is in front of the ALARM AUDIO
option.
3. Press the EDIT ALARM menu key.
4. Use the up/ down cursor keys to toggle the setting ON or OFF.
5. Press ENTER to make your selection, or CLEAR to leave it un-
changed.
(NOTE: If you do not want to be notified of any other navigational
alarms, set the ANCHOR DRAG, CROSS TRACK, ARRIVE RADIUS,
and DGPS alarms to OFF. The audible alert will now only beep when you
enter an avoidance area.)
CAUTION:
The 941X’s avoidance alarm is intended only as an extra added
safety feature to help make you aware of possible hazards. It
does not replace local knowledge, proper use of charts, the per-
son on watch, or any other aspects of good seamanship that are
required for safe navigation.
Page 40
4 — Creating Waypoints and Routes
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Waypoints contained in your 941X can be displayed in any of four ways.
Press the WAYPTS/ ROUTES function key, then the WAYPT LIST
menu key to display waypoint lists. Use the NEXT LIST menu key to se-
lect the list that is best for your current situation. Each press of the
NEXT LIST menu key displays a waypoint list in the following order:
ALPHA, SAVED, AVOID and LOCAL, then starting again at ALPHA.
Wayp oin t Lis ts
ALPHA list: all waypoints in alpha-
betical order
SAVED list: all waypoints
created via SAVE/ MOB key,
with most recent first.
AVOID list: Avoidance waypoints within 100
LOCAL list: 30 closest waypoints within
nm,
100 nm,
nearest first
nearest first
Waypoints listed under the ALPHA screen in the 941X’s memory are
displayed in alphabetical order. Waypoints with a digit as the first char-
acter appear near the beginning of the list. “Saved” waypoints appear
near the end.
alp h a lis t
Rev. D
4 — Creating Waypoints and Routes
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All saved waypoints (stored by pressing the SAVE/ MOB button, and
having a name such as –S001–) are listed in order of the time at which
they were saved, with the most recent first.
s aved lis t
Up to 30 avoidance points within 100 nautical miles are listed in order of
their distance from your position.
avoid lis t
local lis t
In the LOCAL list, up to 30 of the closest waypoints within 100 nautical
miles are listed in order of distance from your position. This list is par-
ticularly useful when you wish to deal with only the waypoints in your
area. Even though you may have hundreds of waypoints stored, the local
waypoints are very often the only ones you are interested in. You may
find yourself using this list most of the time.
Whenever a waypoint list is displayed, you may display the waypoint’s
coordinates on the right side of the screen in any of the following ways,
by pressing the COORD OPTION menu key:
Coord in ate
Op tion s
1. latitude/ longitude coordinates
2. coordinates originally used to save the waypoint (TDs, lat/ lon)
3. distance and bearing from your position (this is often the most
useful way, since it may be easier to visualize “3 miles north” than
the digits of lat/ lon coordinates).
The letter “S” to the right of the waypoint name indicates that the dis-
played coordinates were the ones used to store the waypoint (TDs vs.
lat/ lon).
Often a waypoint is taken from a chart by measuring the approximate
coordinates with whatever accuracy is allowed by the chart. When you
sail to the waypoint, you may find its position is slightly different than
expected. The 941X has a special feature that allows you to easily re-
calibrate the waypoint by setting its coordinates to your precise position.
You can also use this feature to convert approximate loran TD coordi-
nates to precise GPS coordinates.
Up d atin g
Wayp oin t
Coord in ates
Page 42
4 — Creating Waypoints and Routes
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To update a waypoint’s coordinates, first sail to the spot where the way-
point will be located. Press WAYPTS/ ROUTES, then the WAYPT LIST
menu key, to display a list of waypoints on the screen. Press the NEXT
LIST menu key, if necessary, to show the local waypoints (in order of
distance from your position). Your waypoint should be at or near the top
of this list. Use the up and down arrow keys to point to the desired way-
point. Press the EDIT menu key, and then the UPDATE COORD menu
key, and finally the ENTER key.
"
The new coordinates are recorded at the instant you press the UPDATE
COORD menu key.
To change any information about a waypoint you have already stored
(except the type of coordinates used to save it), use the EDIT
WAYPOINT function.
Ed iting
Wayp oin ts
Press the WAYPTS/ ROUTES key, then the WAYPT LIST menu key to
display a list of waypoints. Use the up and down arrow keys to point to
the desired waypoint. Press the EDIT menu key. You may change the
name, description, coordinates and/ or warning radius of the waypoint.
"
Set the warning radius to zero if you want to remove the avoidance fea-
ture from this waypoint. In addition, you can press the UPDATE
COORD menu key to correct the waypoint’s coordinates, as described in
the previous section. Press the ERASE menu key to permanently erase
the waypoint from the 941X’s memory. (Note: You can’t erase it if it is
used in a route—you must first erase it from the route. See “Changing a
Route” on page 50 for more route editing information.)
Rev. D
4 — Creating Waypoints and Routes
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If you store a large number of waypoints or routes in the 941X, or if your
waypoints are the only records you have of important locations, you
should consider making a copy of them by transferring them into a per-
sonal computer using special transfer software (provided by a third party
vendor) and a Northstar loader cable (part #1100-LC). With this system,
waypoints and routes can be copied, edited or plotted, and, most impor-
tantly, can be reloaded into your 941X in the event they are accidentally
erased or lost due to equipment failure. Consult your authorized North-
star dealer for software and cable ordering information.
Trans ferring
Wayp oin ts to a
PC
A route is a sequence of waypoints stored in the 941X. You can store up
to a maximum of 500 routes in the 941X’s memory. There are two meth-
ods by which you can create a route: 1) constructing a route from way-
points already stored in the 941X’s memory, and 2) saving a route as you
travel it.
Creatin g
Rou tes
You may create a route from the waypoints stored in the 941X’s memory
by first pressing the WAYPTS/ ROUTES key, and then pressing the
ROUTE LIST menu key. The names of any routes already stored are
displayed.
"
Page 44
4 — Creating Waypoints and Routes
Rev. D
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Press the NEW menu key. A screen is displayed asking you to enter the
name of the new route.
Enter the name of the new route using the keypad and cursor arrow keys,
as described on page 36, and press ENTER. The NEW ROUTE way-
points screen will be displayed, ready for you to begin selecting way-
points to add to the route.
rou t e n am e
Rev. D
4 — Creating Waypoints and Routes
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To add waypoints to the route, press the INSERT menu key. A list of
in s ert in g
stored waypoints is displayed.
wayp oin t s
Scroll the waypoint list up or down using the cursor keys to designate the
desired waypoint, and press ENTER. The selected waypoint is now in the
route.
Press the NEXT LIST menu key, if you wish, to select different
waypoints from the alpha, local or saved lists. (Avoidance
points cannot be used as waypoints in a route.)
Repeat for each waypoint you wish to enter.
You can insert a waypoint in any part of a route. Waypoints are always
inserted into the route at the point indicated by the arrow at the left of
the screen. Move the arrow so that it is halfway between the two existing
waypoints of the route where you want the new waypoint to be located.
Follow the “inserting waypoints” procedure above for inserting this new
waypoint into the route.
You can also create a new waypoint as you enter it into the route. After
pressing INSERT from the NEW ROUTE waypoints screen, press NEW
.from the SELECT WAYPT screen. Enter the name (with description, if
you wish) and coordinates of your new waypoint. Press ENTER. The new
waypoint is now part of the new route and stored among the waypoint
lists in the 941X’s memory.
creat in g n ew
wayp oin t s
d u rin g rou t e
en t ry
Page 46
4 — Creating Waypoints and Routes
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As waypoints are entered, the distance and bearing of each leg of your
route are displayed on the NEW ROUTE screen. To see an overhead plot
of the entire route, press the QUICK PLOT menu key. It is good practice
to use these two features to check that the route matches your expecta-
tions, ensuring that no errors were made in selecting waypoints.
verifyin g en t ry
The entire route is displayed, with the plotter scale automatically ad-
justed to show all of the waypoints.
To see more detail about a portion of the route, use the NEXT WAYPT
and PREV WAYPT menu keys to advance along the route or move back
towards the beginning. Use ZOOM IN and ZOOM OUT to display a
smaller or larger area. Press RETURN when finished viewing, to go back
to the previous screen.
A second way to create a route is to travel the length of the desired route,
Savin g a Rou te
pressing the SAVE/ MOB button at each location you wish to store in the
route. The 941X's
function makes this a very simple proc-
SAVE ROUTE
ess. In summary, you first tell the 941X that you wish to save a route as
you travel, then press the SAVE/ MOB button as you pass each waypoint,
and then tell the 941X to stop saving the route when you come to the end
of the route.
First, press the WAYPTS/ ROUTES key, and then press the ROUTE
LIST menu key to access route functions. The names of any routes al-
ready stored are displayed:
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Press the SAVE menu key on the lower right of the display to instruct the
941X to begin saving a route automatically. A screen is displayed asking
you to enter the name of the new route to be saved.
Enter the name of the new route to be saved, using the keypad and cur-
sor arrow keys, and press ENTER. The 941X displays the message
“SAVING TO: [route name]” at the bottom of the ROUTES screen con-
firming that your route is now being saved.
rou t e n am e
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4 — Creating Waypoints and Routes
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As you pass the location of each new waypoint, press the SAVE/ MOB
key to the left of the display (not the SAVE menu key in the lower right of
the screen). The boat's location will be saved as a waypoint in the unit's
memory, and the waypoint will automatically be added to the route being
saved. The waypoint will be stored with a name similar to (0001). The
parentheses ( ) indicate that the waypoint is part of a saved route, and
the four-digit number is used to uniquely identify each waypoint. Each
waypoint is automatically given a description consisting of the time and
date when the waypoint was stored.
s t orin g
wayp oin t s
You can access any of the 941X’s navigating functions while you are sav-
ing a route automatically, with the exception of editing the route you are
presently saving. If, at any time, you are unsure as to whether you are
still saving a route or not, press the WAYPTS/ ROUTES key, then the
ROUTE LIST menu key to display the ROUTES screen. If you are pres-
ently saving a route, the message “SAVING TO: ” will be at the bottom of
the screen.
When you have reached the end of your new route, or if you wish to stop
automatically saving the route at any time, go to the ROUTES screen (if
you are not presently displaying it), as described above. Press the STOP
SAVE menu key. The 941X will prompt you with a question window,
asking if you want to “STOP SAVING TO ROUTE XXX?”. Press ENTER
for “YES.” The “SAVING TO: ” message at the bottom of the screen is ex-
tinguished.
en d in g t h e rou t e
Rev. D
4 — Creating Waypoints and Routes
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To make a change to a route stored in the 941X's memory, use the EDIT
ROUTE function. Press WAYPTS/ ROUTES and then the ROUTE LIST
menu key to display the ROUTES screen.
Ch an g in g a
Rou te
Use the up or down cursor keys to point to the route you wish to change.
Press the EDIT key. The route name is displayed.
If you wish to change the route’s name, do so now, then press ENTER. If
not, press ENTER to continue.
A screen appears which displays the waypoints in the route and allows
you to insert or remove waypoints from the route.
Page 50
4 — Creating Waypoints and Routes
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To insert a new waypoint, use the up and down cursor keys to move the
pointer to the spot between the two existing waypoints where you want
to make the insertion, and press the INSERT menu key. A screen listing
waypoints is displayed.
in s ert in g
wayp oin t s
Move the cursor to select the waypoint from the displayed list, and press
ENTER. You will see the selected waypoint now in your route.
To remove a waypoint from the route, use the up and down arrow keys to
move the pointer to the waypoint, and press the REMOVE menu key,
and then ENTER.
rem ovin g
wayp oin t s
If you make changes to a route you are currently navigating along, re-
member that the modified route is stored back in the 941X’s memory,
but these changes do not appear in the copy of the route the 941X is fol-
lowing.
ed it in g a rou t e
you are
followin g
To make these changes take effect, you must start following the route
again (see page 59).
"
To display each waypoint’s coordinates instead of its name and descrip-
ot h er wayp oin t
fu n ct ion s
tion—while editing or creating a route—press the NAME/ COORD menu
key.
Rev. D
4 — Creating Waypoints and Routes
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To plot an overhead view of the route, press the QUICK PLOT menu
key.
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4 — Creating Waypoints and Routes
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5
Wayp oin t an d Rou te
Navig ation
Quick-Start Waypoint 54
Navigating to Waypoints 55
Navigating Along Routes 59
Restarting the Course Line 61
In this section, we’ll begin navigating to specific waypoints
and along routes, and show you how to get back on course,
or follow a new course line to your destination.
Rev. D
5 — Waypoint and Route Navigation
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he 941X’s “Quick Waypoint” feature allows you to enter coordinates
Qu ick Start
Wayp oin t
Tand start navigating in one quick and easy sequence.
Press the WAYPTS/ ROUTES key, and then press the QUICK WAYPT
menu key. A screen for entering waypoints appears.
Key-in the coordinates of the waypoint (just as you would normally store
a waypoint) and press ENTER twice.
The 941X stores the waypoint as a “–QUIK–” waypoint, and will imme-
diately begin navigating to it.
To change the type of coordinates you want to enter—from lat/ lon, to
distance and bearing, or to loran TDs—press the COORD TYPE menu
key to show the type you wish to use.
coord in at es
Coordinates may be entered as:
1. latitude/ longitude of any point in the world
2. distance and bearing from “here” (your present position), or from
any waypoint in the 941X’s memory
3. loran TDs (make sure the GRI displayed is correct; change it if nec-
essary).
The coordinates you enter will be stored in the 941X's memory as a way-
point named “–QUIK–.” This waypoint’s coordinates will be overwritten
the next time a QUICK waypoint is entered.
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5 — Waypoint and Route Navigation
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WAYPOINT TIP
You can specify a waypoint to navigate to, and store it perma-
nently in the 941X’s database in one operation, if you like.
QUICK WAYPT
While in the
sor arrow up to the waypoint’s name and change it from
-QUIK- ENTER
entry screen, just move the cur-
to its permanent name before pressing
. To
make a previously-entered QUICK waypoint become a perma-
nent waypoint, just go to a waypoint list screen and edit the
name (and description, if you wish).
To navigate to a waypoint already stored in the 941X, first display it us-
ing one of the four waypoint list screens: press WAYPTS/ ROUTES, then
the WAYPT LIST menu key. Use the up and down cursor arrow keys to
move the large arrow on the left of the screen so that it points to the
waypoint you want to navigate to. Then press the GO TO menu key, and
then ENTER.
Navig atin g to
Wayp oin ts
WAYPOINT TIP
Since the waypoints you navigate to are usually nearby, the
LOCAL waypoint list is often the best list to use for finding the
waypoint in the database.
The 941X will automatically switch to the STEER display to show infor-
mation for navigating to the waypoint. You can also press the STEER key
to display this information at any time. Two versions of the screen are
available to choose from.
Rev. D
5 — Waypoint and Route Navigation
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The first STEERING screen is a traditional display showing cross-track
distance at the bottom of the screen (how far off your intended course
line you may be) combined with numeric information depicting the dis-
tance to your destination waypoint, your present bearing to that way-
point, your present SOG, and your present COG.
ch oos in g a
s t eerin g s creen
The “3-D” steering screen is a waypoint “heading-up” display showing
the waypoints between you and the destination waypoint, and your posi-
tion relative to the course line for precision steering. Both steering
screens are intended to guide you precisely along a course line which
might follow a harbor channel, or a line between shoals and sandbars.
The first STEERING screen displays your distance and bearing to the
waypoint, along with your Speed-Over-Ground and Course-Over-Ground
on the upper part of the readout. The digits are large and can be read
from a distance. An arrow between the SOG and COG displays points
upwards when the trend of your speed is increasing, and down when it is
decreasing.
d is t an ce an d
b earin g
The center of the screen has a user-selectable area which can be set to
display any of the information listed below. Press the middle menu key
to change the type of data displayed:
ot h er
in form at ion
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1
2
3
In the first steering screen above, a line extends from the data box in the
center of the screen to a menu key. Each press of the menu key changes
the data displayed in the box among three choices, as follows:
1. Estimated Time En Route (ETE) to the waypoint, and Estimated
Time and Date of Arrival (ETA)
2. Speed of Advance (SOA) and Heading Correction
3. Waypoint’s name and description, and its coordinates
The lower part of the screen displays your off-course distance, using a
picture of your boat to show your distance from the course line. In addi-
tion, the direction of the boat on the screen indicates the direction your
boat is actually traveling. (Note: this may not be the same as your head-
ing if any current or wind is present.) When the picture of your boat
points towards the course line, you are moving closer to the line. When it
points parallel to the course line, you are keeping a constant distance
from the line. When it points away from the course line, you are moving
further from the line.
off-cou rs e
d is t an ce
Your distance from the course line is also displayed in numbers at the
bottom of the screen. See page 85 for customizing the cross-track display
format.
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5 — Waypoint and Route Navigation
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Two vertical lines near the edge of the screen indicate the limits of off-
course distance. An alert message will be given if these limits are ex-
ceeded, and the image of your boat will flash on and off. Press the STAR
button to display the alert message, then the CLEAR ALARM menu key
to acknowledge and clear it.
NOTE
As you pass a waypoint while following a route, the image of
the boat may swing around vigorously as it points to the way-
point you are passing. When the 941X switches to the next
waypoint, the boat image will snap back to pointing straight
ahead.
The 3-D STEER display features a three-dimensional view of your boat,
the current waypoint, the course line to the waypoint, and the locations
of any other nearby waypoints. It is intended to provide a comprehensive
picture of your progress toward the waypoint.
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5 — Waypoint and Route Navigation
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To follow a route that has been stored in the 941X’s memory, press the
WAYPTS/ ROUTES key, then the ROUTE LIST menu key. Use the cur-
sor keys to select the route you wish to follow, and then press the GO
menu key. The first four waypoints of the route are displayed.
Navig atin g
Alon g Rou tes
s t art in g t h e
rou t e
1
2
Notice that the arrow shape alternates as you move the cursor up and
down. The first arrow shape designates a single waypoint of the route.
The second designates a leg connecting two waypoints. The two shapes
allow you to start following a route in either of two ways:
1. DIRECT TO WAYPOINT: You may navigate directly from your pre-
sent position to a designated waypoint. To start on a waypoint
other than the first, use the cursor keys to move the pointer to the
desired waypoint, as in screen #1 above. Press the GO menu key,
then ENTER.
"
2. ALONG A LEG: You may tell the 941X that you want to navigate
along a designated leg of the route. Move the cursor down until it
Rev. D
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changes to a connecting arrow between the two waypoints, as in
screen #2 above. Press the GO menu key, then ENTER.
To start following the route, select the waypoint or leg you want to start
on, press the GO menu key, then ENTER.
Before you actually start the route, you can display planning information
about the route in the GO ALONG ROUTE screen. An estimate of the
time required to travel to the selected waypoint is displayed near the top.
As you scroll the pointer up or down, the ETA will change for each way-
point. This estimate is based on the Speed-Over-Ground figure displayed
at the bottom of the screen.
p lan n in g ETA t o
an y wayp oin t
To change this figure, press the USUAL SOG menu key and enter the
new value to be used in calculating the time. Use the cursor arrow keys
again to scroll through the Estimated Times of Arrival for different way-
points of the route.
"
To access the USUAL SOG and waypoint ETA features from any screen,
proceed as though you were going to follow a route by pressing the
WAYPTS/ ROUTES key, then ROUTE LIST, then select the route you
wish to view. Press GO to display the ETA of each waypoint in the route
and the USUAL SOG window at the bottom of the screen. To exit with-
out actually following the route, press any function key.
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The distance and bearing of each leg are displayed near the center of the
screen.
d is t an ce &
b earin g
To display the coordinates of each waypoint in place of the name and de-
wayp oin t
scription, press the NAME/ COORD menu key.
coord in at es
To plot an overhead view of the route, press the QUICK PLOT menu
key. When displaying the plot, you may use the NEXT WAYPT and
PREV WAYPT menu keys to advance along the route or move back to-
wards the beginning.
q u ick p lot
Use ZOOM IN and ZOOM OUT to display a smaller or larger area.
When you have finished looking at the plot, press RETURN to go back to
the previous screen.
When navigating from one waypoint to another, you may find you have
wandered off the intended course line. Perhaps you may have avoided an
obstacle, or simply drifted slightly off-course. Whenever you are off-
course for any reason, you may choose either of two methods for getting
back on course.
Res tartin g th e
Cou rs e Lin e
After passing the obstacle, you may steer the boat back to the original
course line using the Cross-Track error display (Course 1 below), and
continue to the waypoint.
Rev. D
5 — Waypoint and Route Navigation
Page 61
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If you do not need to return to the original course line, you can continue
directly to the waypoint (Course 2) using the restart function described
below.
To restart your course line from your present position, display the NAV
LOG screen or the POSITION PLOTTER screen. Press the RESTART
menu key, then the ENTER key. The 941X will recompute the course line
to extend from your present position directly to the next waypoint, re-
setting your cross-track error to zero.
"
Page 62
5 — Waypoint and Route Navigation
Rev. D
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6
Th e NAV LOG Fu n ction
What NAVLOG Does 64
Logging Your Trip 65
Changing Your Trip 65
Adding Waypoints to the Trip 66
The Northstar 941X’s NAV LOG function provides a quick
and easy way to check on your progress along a trip, and to
make changes to it while you travel.
Rev. D
6 — The NAV LOG Function
Page 63
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HE Northstar 941X’s NAV LOG feature helps you plan and log your
Wh at NAV LOG
Does
Ttrip. It contains the actual series of waypoints that you follow along
your route. When you navigate to a waypoint or along a route from the
941X’s memory, the string of waypoints are copied into the NAV LOG,
which acts as a kind of “scratchpad” for monitoring your progress. You
can modify NAV LOG’s route in any way you want without affecting the
original route, which remains safely stored in the unit’s memory.
NAV LOG provides two main functions: It shows your progress along
your trip, and it lets you easily change the remainder of your trip.
Information for safe and efficient planning of your trip is updated as you
travel. Your Estimated Time of Arrival (ETA) at the last waypoint in the
route is shown at the top of the screen, and the Estimated Time Enroute
(ETE) to each waypoint is shown below each waypoint name.
ETA an d ETE
A darkened arrow connecting the right ends of two waypoint boxes indi-
cates you have completed that leg of the trip.
p as s s t at u s
res t art
You may restart at any leg or to any waypoint of the route by moving the
cursor arrow to the waypoint or leg and pressing the RESTART menu
key.
Page 64
6 — The NAV LOG Function
Rev. D
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You can reverse the trip at any time (navigating to route waypoints in
revers in g t h e
t rip
reverse order) by pressing the REVERSE menu key.
Waypoints may be added to the trip by pressing the APPEND WAYPT
menu key. Any waypoints added to the trip in NAV LOG are not perma-
nently appended to the route in the 941X’s memory. To make permanent
changes to the route, you must use the EDIT ROUTE functions, as de-
scribed on page 50.
ap p en d in g
wayp oin t s
Waypoints are automatically entered and organized in NAV LOG when
you first navigate (GO) to a waypoint or along a route.
Press the NAV LOG key at any time to display the list of waypoints you
are currently navigating along. Use the up and down cursor arrow keys
to scan through the entire list to show any waypoint you wish. The dis-
tance and bearing of each leg is displayed. For each waypoint, you can
display either the waypoint’s description, or the time of arrival at the
waypoint. Press the NAME/ ETA menu key to select one or the other.
Log g in g You r
Trip
The time of arrival displayed is the Estimated Time of Arrival (based on
your current speed) for waypoints you have not yet passed. Actual Times
of Arrival are shown for waypoints you
passed.
have
Remember, estimated times are just that—estimates—and may
be inaccurate. This is because your Speed-Over-Ground will be
affected by any changes in direction, even slight changes
brought about as you pass through varying currents.
Press the NAV LOG key, as above, to display the waypoints of your cur-
Ch ang in g You r
Trip
rent trip. You may modify the remainder of your trip by:
•
•
•
adding a waypoint to the end of the trip
skipping to any waypoint within the trip
reverse the trip from present position to follow it back to the be-
ginning
Rev. D
6 — The NavLog Function
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Under NAV LOG, the distance and bearing of each leg are displayed.
You can easily read the direction of the next leg of your trip from this
display.
Press the NAV LOG key to display the waypoints of your current trip. To
add a waypoint to the end of the trip, press APPEND WAYPOINT. A list
of the waypoints stored in memory is displayed. Use the up and down
cursor arrow keys to select the desired waypoint. (Press NEXT LIST, if
you wish, to display the waypoints list in a different order.) Press ENTER
to add the waypoint to the NAV LOG. Repeat for any other waypoints
you want to add.
Ad d in g
Wayp oin ts to
th e Trip
Page 66
6 — The NAV LOG Function
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7
Oth er Sp ecial Fu n ction s
Alarms 68
Screen Backlighting
71
TideTrack™ 71
Internal Differential Beacon Receiver 74
This section covers several special functions that enable
you to: change the 941X’s audible alarms and screen ap-
pearance; navigate using the unique TideTrack™ feature;
get the most out of the high-precision positioning capabili-
ties of your internal or external Differential GPS (DGPS)
receiver.
Rev. D
7 — Other Special Functions
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everal special 941X functions are controlled by the STAR function
Skey (
). These include alerts and alarms, TideTrack™ functions,
and setup functions.
The Northstar 941X has a number of automatic alarms that can alert you
of special situations. For example, when you are approaching a waypoint,
the 941X signals you with a distinctive “beep” and a flashing exclamation
point symbol on the screen.
Alarm s
At any time, you can press the STAR button (
) to access the
ALARMS & BACKLIGHT screen which displays the cause of the most
recent alarm.
The 941X’s alarm types and descriptions are:
AUTO
TYPE
DESCRIPTION
CLEAR?
you have come within 900’ of the
arrival circle of the current way-
point (arrival circle radius set
from ALARMS & BACKLIGHT
screen)
YES, after 5
seconds
CLOSE
you have entered the arrival cir-
cle of the current waypoint
while navigating to waypoint,
perpendicular to track passed,
but arrival circle was not entered
switching to next leg of route
(“NOW NAVIGATING TO . . . ”)
avoidance area circle has been
entered
anchor is dragging beyond limit
set from ALARMS &
BACKLIGHT screen
no position fix received from ex-
ternal loran
YES, after 5
seconds
YES, after 5
seconds
ARRIVE
PASS
YES, after 5
seconds
NO: potential
hazard ahead
NO: requires
immediate
attention
YES, when
condition
clears
CHANGING
AVOIDANCE AREA
ANCHOR DRAG
NO LORAN FIX
DGPS data timeout exceeded
no position fix from GPS
communication failure with ex-
ternal loran
“
"
"
DGPS LOST
NO GPS FIX
NO LORAN DATA
communication failure with GPS
BLINK, CYCLE or LOW SNR
detected at loran
"
"
NO GPS DATA
POOR LORAN FIX
off-course in excess of limits set
in CROSS TRACK ALARM
only when
within limits
CROSS-TRACK
LIMITS EXCEEDED
Page 68
7 — Other Special Functions
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Though most alarm conditions are “auto clearing” after approximately
five seconds, and do not require any user action, two alarms—
AVOIDANCE AREA and ANCHOR WATCH—must be acknowledged
before the exclamation point can be cleared from the screen.
The most recent instance of an alarm type (waypoint, communications,
avoidance area, anchor and cross-track alarms) is retained in the 941X’s
memory. This is helpful for viewing those “auto-clear” alarms that you
may have been unable to acknowledge before the flashing exclamation
symbol was automatically cleared. Each successive press of the CLEAR
ALARM menu key displays the most recent message for each type of
alarm.
Four of the alarm controls are adjustable, as described below. To change
any of these, use the up and down cursor keys to move the arrow on the
screen to the control you want to edit. Press the EDIT ALARM menu
key. Use the up or down arrow keys to select the status you want, and
finally press ENTER.
"
The audio beep that alerts you to alarm conditions can be turned on or
off.
alarm au d io
1. Select ALARM AUDIO, using the up/ down cursor arrow keys.
2. Press the EDIT ALARM menu key.
"
3. Use the up/ down cursor arrow keys to display OFF or ON.
4. Press ENTER to make your selection, or OFF to leave it unchanged.
Rev. D
7 — Other Special Functions
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When ALARM AUDIO is set to ON, the 941X will audibly alert you to
any of the alarm conditions turned ON at the ALARMS & BACKLIGHT
screen.
The anchor watch feature of the 941X will sound an alarm if the unit de-
tects that the boat has moved a specified distance away from an initial
position.
an ch or wat ch
1. Press the DROP ANCHOR menu key at the spot where the anchor
"
is dropped.
2. Press ENTER in response to the question window prompt.
3. Move the cursor arrow to ANCHOR ALARM and press the EDIT
ALARM menu key.
4. Use the up/ down cursor keys to turn the alarm ON.
5. Move the cursor to the right and use the keypad to specify the dis-
tance the boat can be expected to move on its anchor chain (plus a
safety factor to allow for GPS or loran inaccuracy).
6. Press ENTER.
Remember to turn the ANCHOR WATCH alarm off before intentionally
moving away from the anchor drop point.
The cross track alarm allows you to specify the maximum distance the
boat will be permitted to move from the track line without sounding an
alarm. You can turn the cross track alarm on or off, and specify the alarm
distance from the track line.
cros s t rack
alarm
1. Move the cursor arrow to CROSS TRACK.
"
2. Press the EDIT ALARM menu key.
3. Choose whether you want the cross-track alarm ON or OFF with
the up/ down cursor keys.
4. If you want to change the limit at which the cross-track alarm will
alert you, use the right arrow cursor key to move to the digits field.
5. Using the keypad, specify the distance at which you want to be
alerted, and press ENTER.
Page 70
7 — Other Special Functions
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The ARRIVE RADIUS alarm signals you when you come within a speci-
fied distance of the next waypoint. You can specify the distance of the
radius around waypoints down to 0.01 nm.
arrive rad iu s
1. If you want to change the limit at which the arrive radius alarm will
"
alert you, move the cursor arrow to ARRIVE RADIUS.
2. Press the EDIT ALARM menu key.
3. Using the keypad, specify the distance at which you want to be
alerted, and press ENTER.
NOTE: Keep this distance very small because the 941X will automatically
begin to sequence to the next waypoint when you come within the arrival
distance you have set for the current waypoint.
The DGPS ALARM signals when the 941X has operated without differ-
ential corrections beyond the DGPS data timeout limit. (See “DGPS data
timeout,” beginning on page 89, for details.)
d g p s alarm
1. If you want to activate the audible DGPS timeout alarm, move the
"
cursor arrow to DGPS ALARM.
2. Press the EDIT ALARM menu key.
3. Use the up/ down cursor keys to turn the alarm on or off, and press
ENTER.
To change the level of backlighting of the unit’s screen and keys:
Screen
Backlig hting
1. Press the STAR key to display the ALARMS & BACKLIGHT
screen.
2. Press the BRIGHT menu key to make the lighting brighter.
3. Press the DIM menu key to dim the lighting.
The 941X calculates tide information for any of over 3,000 NOS/ NOAA
tide stations. The entire U.S. coastline—including Alaska and Hawaii—is
covered, plus many Caribbean islands and western Canada. Tides may be
Tid eTrack
Rev. D
7 — Other Special Functions
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displayed for any date from 1994 to 2010. Data is from the official tide
table predictions and should be as accurate as the printed tables. (Please
refer to
, published by the NOS/ NOAA, Rockville, Maryland
Tide Tables
20852, for more information on tides.)
To use TideTrack, press the STAR key until the TideTrack graphic is
"
displayed.
The water height for any 24-hour period is displayed for the selected
NOAA tide station.
At the top of the screen the selected tide station and the selected day are
displayed.
The center of the screen shows a graphic representation of the tide
height for the entire day. Maximum and minimum heights are shown as
dashed horizontal lines labeled with the height in feet. Mean Lower Low
Water (MLLW) is shown as a solid line near the bottom of the picture. A
vertical line and arrow are positioned to show the tide level for the cur-
rent time.
At the bottom of the screen, the times of the day’s high and low tides are
shown for that location, along with the height at the present time.
You may display tide information for any of over 3000 NOAA tide sta-
tions stored in the 941X. You can select from any of the nine tide stations
closest to your present position, or you may select from any of nine tide
stations closest to any waypoint stored in the 941X.
ch oos in g a
n earb y t id e
s t at ion
Page 72
7 — Other Special Functions
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To choose a nearby tide station, press the CONFIG key while viewing the
TIDE TRACK screen.
"
Press the CHOOSE CLOSEST TIDE STATION menu key. The 941X
will search for the nine closest stations to your present position and pre-
sent a list like the following, organized by closest station at the top:
Use the up and down arrow keys to point to the desired station, and
press ENTER twice to return to the TIDE TRACK screen and display the
tides for that station.
The 941X will display NOAA tide stations within 100nm of any waypoint
stored in its memory. (You can always store a waypoint just for the pur-
pose of locating tide stations in that area, at a later date. Refer to
“Creating Waypoints,” on page 37, for more information on storing a
waypoint.)
ch oos in g a
d is t an t t id e
s t at ion
To choose a tide station near a waypoint, press the CONFIG key on the
TIDE TRACK screen. Press the CHOOSE CLOSEST STATION TO
WAYPOINT menu key. A list of the 941X’s waypoints is displayed.
"
Rev. D
7 — Other Special Functions
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Use the up or down cursor arrow keys to point to the desired waypoint,
and press ENTER. The 941X will search for, and present, the nine closest
tide stations to this waypoint. Now, use the up and down arrow keys to
point to the desired station, and press ENTER twice to return to the
TIDE TRACK screen and display the tides for that station.
The TIDE TRACK screen normally displays tide information for today’s
s elect in g a d ay
date.
To enter a different date, press the CONFIG menu key; the TIDE
TRACK CONFIGURATION screen is displayed. Press the NEW DATE
menu key. The first character of the present tide date flashes. If neces-
sary, press the right cursor arrow to move to the month or digit you wish
to change. To change a digit, press that key on the keypad. To change the
month, use the up and down cursor arrow keys. When the date is correct,
press ENTER twice. Tide information for the new date is now displayed.
"
As we previously discussed in “Comparing GPS and Loran,” beginning on
page 5, use of differential corrections significantly enhances the accuracy
and performance of your 941X. One source of differential corrections is
Northstar’s fully automatic beacon receiver, which may be connected
Internal
Differential
Beacon
Receiver externally (part #8800) to the 941X, or contained internally (#8500).
Or, you may connect another source of corrections externally (see page
124 for further details on interfacing to external sources of differential
corrections).
The Northstar beacon receiver takes corrections broadcast by shore-
based marine radio beacons situated along most of the U.S. coastline.
Page 74
7 — Other Special Functions
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These corrections are used by your 941X to improve its position accuracy
to 10 meters—or better—with 2-5 meters accuracy commonly available.
Differential corrections are invaluable when navigating in narrow or
congested areas (such as ports and waterways), or whenever extreme ac-
curacy is required for locating a precise area (retrieving lobster pots, re-
turning to a diving spot, etc.).
Northstar beacon receivers require no manual operation. They automati-
cally tune to the appropriate beacon frequency as you move from one
beacon coverage area to another, or as weather conditions change. Avail-
able radio beacon signals are constantly evaluated for signal quality by
the receiver, and only the best station is selected. As you travel, the
Northstar beacon receiver is prepared to switch to another frequency
automatically, as conditions require.
The 941X, with a Northstar beacon receiver, enters automatic differential
mode as soon as SC-104 DGPS corrections are received and requires no
further supervision, as far as differential operation is concerned. The
beacon receiver maintains automatic operation by using two independ-
ent receiver channels. Channel 1 tracks the best available beacon signal
(the one with the lowest data error rate) and sends the demodulated
DGPS corrections to the 941X GPS receiver. Channel 2 continuously
scans the entire beacon frequency band (283.5 to 325kHz), locating and
measuring received DGPS beacon signals. The unit then stores this in-
formation as a DGPS beacon “directory” in its battery-powered memory.
au t om at ic m od e
If the signal being received and monitored by Channel 1 degrades for any
reason, the unit tries to select a better frequency from its beacon mem-
ory. This allows it to switch to the best beacon signal before your GPS
accuracy can be affected.
Automatic mode can normally be used for all but specialized applica-
tions.
At any time, you can override automatic beacon station selection of the
beacon receiver by issuing tuning commands from the keypad. In man
m an u al m od e
Rev. D
7 — Other Special Functions
Page 75
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ual mode, the beacon receiver will output DGPS corrections only from
the selected station. Though the need for manual operation is rare, it is
easily accessed from your 941X keypad.
To manually choose a beacon, you must select the frequency and baud
rate (the beacon’s data transmission speed) of the desired beacon.
1. To first change the frequency, press the STAR key until you display
the USER CUSTOMIZATION screen.
"
2. Press the RECEIVER OPTIONS menu key. Move the cursor to
BEACON FREQUENCY and press the EDIT menu key.
3. Press the down cursor key once, to change from “AUTO” to
“MANUAL.” A beacon transmitter frequency will appear to the
right of the word “MANUAL.”
4. Use the right cursor key to highlight the digits you wish to change.
Enter the appropriate frequency and press ENTER when you are
done.
You may also manually set the baud rate for the selected beacon fre-
quency.
BEACON
However, it is strongly recommended to leave the
BAUD RATE AUTO.
setting at
NOTE
A non-Northstar external beacon receiver cannot be manually
controlled by the 941X, unless it supports the MX50R control
protocol. Refer to the beacon receiver manufacturer’s instruc-
tions to determine if this control protocol is supported.
If the beacon receiver stops receiving differential data, the 941X will
continue navigating for a short time using the old DGPS corrections. Re-
ception of the DGPS data can be interrupted by bad weather, severe
thunderstorms, extreme distance from the beacon, etc.
DGPS d at a
t im eou t
You may allow the 941X to navigate for a set period of time using this old
data with no DGPS interruptions. To change the data “timeout” period,
refer to page 89.
Page 76
7 — Other Special Functions
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8
Cu s tom iz in g th e 941X
Time of Day 78
Display Options 78
Navigation Options 82
Port Setup Options 90
Service Options 91
Geodetic Datum 94
his section explains the various options available to you
for customizing the way your 941X displays informa-
tion to you, computes navigation data, and “talks” to other
devices. Each option is changeable at any time, according
to your specific needs.
Rev. D
8 — Customizing the 941X
Page 77
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Press the STAR key until you display the TIME OF DAY screen. The
time, date, local time zone, and time of today’s sunrise and sunset are
shown.
Tim e of Day
Also displayed is the current time expressed as “GMT” (Greenwich Mean
Time). Note that the day of the week in Greenwich, England may be dif-
ferent from the day in your local time zone (right screen, above).
To change the time zone used for the time display (both here and in
other time displays), press the TIME ZONE menu key, and use the up or
down cursor arrow keys to select the desired zone and standard or day-
light time. Press ENTER to use the new time zone.
"
To access the 941X’s display options, press the STAR key until you dis-
Dis p lay Op tion s
play the USER CUSTOMIZATION screen.
Press the DISPLAY OPTIONS menu key. The following choices are
shown:
Page 78
8 — Customizing the 941X
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To change any of the options (described below), select it by using the
cursor keys to move the arrow at the left of the screen, and then press the
EDIT menu key. The field will begin to flash, waiting for you to change it
using the up/ down cursor keys or the keypad.
"
The 941X offers you the choice of calculating the distance and bearing to
your intended destination as either a GREAT CIRCLE route or a
RHUMB LINE.
d is t an ce, b earin g
as
The shortest distance between any two points on the surface of a sphere
is called a Great Circle route. It appears as a curved line on a Mercator
chart and is the default method of calculating distance and bearing to
waypoints by the 941X.
Rhumb line navigation maintains a constant true direction to your desti-
nation (seen as a straight line on a Mercator chart), but is a somewhat
longer route to travel over great distances than the Great Circle calcula-
tion. A Rhumb Line course may be desired if a Great Circle route is likely
to take you precipitously close to bad weather or an unavoidable land
mass.
You may choose between nautical miles and knots, kilometers and kilo-
meters per hour, or statute miles and miles per hour, for the 941X’s vari-
ous distance and speed displays, respectively.
d is t / s p eed u n it s
To change this option, press EDIT, then use the cursor keys to scroll
among the available choices. Press ENTER to make your selection, or
CLEAR to leave the option unchanged.
"
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8 — Customizing the 941X
Page 79
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NOTE
This option determines whether feet or meters will be used in
STEERING
CROSS-TRACK
the
steering screens’ distance-to-waypoint displays when
STEER DIST PRECISION
screen’s
display, and in both
HIGH
is
option (both selected
selected as the
under NAVIGATION OPTIONS—see pages 85 and 86, respec-
tively).
(DISPLAY OPTIONS)
t im e d is p lay
Time of day may be displayed in either 12- or 24-hour format. The option
you select here affects all of the 941X’s time-related displays, including
high and low tides, sunrise/ sunset, and ETA.
To change this option, press EDIT, then use the cursor keys to scroll
among the two choices. Press ENTER to make your selection, or CLEAR
to leave the option unchanged.
"
(DISPLAY OPTIONS)
lat / lon d is p lay
You may adjust the precision of the 941X’s latitude and longitude posi-
tion displays from degrees, minutes and seconds (two digit places, or
.XX), to degrees, minutes and thousandths of minutes (three digit places,
or .XXX).
To change this option, press EDIT, then use the cursor keys to scroll
among the two choices. Press ENTER to make your selection, or CLEAR
to leave the option unchanged.
"
(DISPLAY OPTIONS)
m ax. s aved
wayp oin t #
The 941X automatically assigns a sequential waypoint number for each
point stored using the SAVE/ MOB button. When this number reaches
the designated value set using this function, the unit starts over at 1 (dis-
played as –S001–), and overwrites any old saved waypoint already des-
ignated as number 1. You can set the maximum number of saved
waypoints which the 941X will store before overwriting old saved points
(see below). For many applications, you may wish to set this maximum
number to a small value, such as five or ten, provided you promptly re-
name any saved waypoints you wish to retain, before they are overwrit-
ten.
Page 80
8 — Customizing the 941X
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To change the maximum saved waypoint number:
"
1. Move the cursor to this option and press the EDIT menu key. The
cursor will begin to flash in the first digit field.
2. Using the numeric keypad, enter the value you want—up to a
maximum of 199—and press ENTER. For one- or two-digit values,
enter a zero as the leading digit(s).
The 941X will now automatically number your saved waypoints up to the
value you have set, at which point it will then begin to overwrite previ-
ously-saved waypoints with your new ones.
(DISPLAY OPTIONS)
own er’s m es s ag e
To provide a substantial measure of theft protection for your Northstar
941X, you may enter a personalized owner identification message using
an access code mailed to you when you return your product registration
card to Northstar. This function asks you to enter this special four-digit
code before you can change the owner’s message.
You can enter your individual owner ID message once you have received
your registered owner access code card:
1. Press the STAR key until you display the USER
CUSTOMIZATION screen.
"
2. Go to DISPLAY OPTIONS and move the cursor arrow down to
OWNER’S MESSAGE: .
3. Press the EDIT menu key. A question window will appear, asking
you to enter your password.
4. Enter the “access code” number from your Northstar ID card and
press ENTER. The first character block of the owner’s message will
flash.
5. Enter the message (up to two lines) you want displayed each time
you power-up your 941X, and press ENTER.
Your message remains unchangeable from this point on, without first
entering your specific access code number and repeating the above pro-
cedure. The 941X will allow three attempts to enter the correct access
code; after that, all operations will “freeze,” requiring the user to shut
power off, then turn it back on again in order to resume functioning.
Rev. D
8 — Customizing the 941X
Page 81
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Press the RETURN menu key to return to the USER CUSTOMIZATION
screen.
The following options control aspects of navigation and the use of GPS
and Differential GPS. Press the STAR key until you display the USER
CUSTOMIZATION screen. Press the NAVI-GATION OPTIONS menu
key to display the following choices:
Navig ation
Op tion s
To change any of the displayed options, move the cursor arrow to that
item and press the EDIT menu key. Use the cursor keys to scroll through
available choices, or the keypad to enter specific values.
(NAVIGATION OPTIONS)
n avig at ion
s ou rce
The 941X’s position displays and navigation to a waypoint are based on
position information obtained from any one of four available navigation
sources:
•
•
•
•
GPS
an external loran receiver
Phantom Loran coordinates calculated from GPS coordinates, or
“DEMO” mode.
Use the NAVIGATION SOURCE option to select which source is to be
used. To change it, press the EDIT menu key and use the up/ down cur-
sor arrow keys to make your selection. Press ENTER when you are done,
or CLEAR to leave the option unchanged.
"
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• GPS can be selected as the navigation source at any time.
• EXTERNAL LORAN can be used if a loran receiver is interfaced
to the 941X (and is operational).
• PHANTOM LORAN can be used if no loran receiver is inter-
faced to the system, but you’d like to see your position displayed
in TD coordinates.
• DEMO mode is used to simulate a stationary position—namely,
the unit’s last position fix—if you want to practice using the 941X
without being on your boat or connected to an antenna. You may
enter a waypoint with the name “DEMO” to establish a new
demo position at that waypoint’s coordinates.
NOTE
If your 941X is equipped with an internal beacon receiver, dif-
ferential GPS corrections (if available) will always be used
when “GPS” or “Phantom Loran” is selected as the navigation
source.
(NAVIGATION OPTIONS)
m ag n et ic
variat ion
Compasses naturally point to the
north pole, which is several
magnetic
hundred miles from the Earth’s actual north pole. The difference be-
tween the two angles is known as . The 941X offers
magnetic variation
you the option of choosing from True (0°), Automatic (the 941X calcu-
lates variation automatically, according to your location), and Manual
(from 0° to 180°, East or West) settings. The factory default is magnetic,
to coincide with your compass. Your navigation charts will indicate the
approximate magnetic variation for each area.
Under most conditions, you’ll want the 941X to calculate the variation
for your position. (Usually, the automatically-calculated
automatically
variation is entirely adequate for use.)
bearings are usually required when using a gyrocompass.
True
The
setting (1° to 180°) is available for those times when the dis-
manual
play must match an older or less accurate chart, or in remote areas (usu-
ally above 70° latitude) where magnetic calculations can be off by as
much as a degree or more.
Rev. D
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Press EDIT to change the 941X’s magnetic variation setting. Use the
up/ down cursor keys to choose AUTO, MANUAL or TRUE. When
choosing MANUAL, move the cursor to the right to enter the value you
want. Press ENTER when you are done, or CLEAR to leave the option
unchanged.
"
(NAVIGATION OPTIONS)
wayp oin t
s wit ch in g (an d
t h e arrive
The 941X can be set to advance automatically to the next waypoint upon
arrival at each waypoint, or it can be set to require manual switching.
rad iu s )
Manual switching may be desirable when maneuvering around a way-
point to find a lobster trap, or when trying to locate a buoy in dense fog.
It allows you to maintain a constant display of distance and bearing in-
formation for the particular waypoint you are using, until you instruct
the unit otherwise.
When set to automatic switching, the 941X will display new distance and
bearing information for the next waypoint upon arrival at the previous
one. It will immediately stop navigating when a lone waypoint—or the
last waypoint in a route—has been passed.
To change the 941X’s mode of waypoint switching, position the arrow to
the left of the WAYPOINT SWITCHING option and press the EDIT
menu key. Use the cursor arrow key to select AUTO or MANUAL. Press
ENTER when you are done, or CLEAR to leave the option unchanged.
"
You have “arrived” at a waypoint when you enter the circle determined
by the waypoint’s ARRIVE RADIUS, or when you pass the perpendicular
of the end point of the current leg you are following. The 941X will signal
that you have arrived by flashing the alert symbol (flashing exclamation
point) in the lower-right portion of the display. You can either acknowl-
edge the alert by pressing the STAR key to display the ALARMS &
BACKLIGHT screen, then pressing the CLEAR ALARM menu key, or
you can wait until it automatically clears itself once you have left the ar-
rive circle. (See page 68 for more on the 941X’s various alarms.)
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The ARRIVE RADIUS factory default is 0.02 nautical miles (approx. 120
"
ft.). To change it:
1. Press the STAR key to display the ALARMS & BACKLIGHT
screen.
2. Move the cursor arrow down to ARRIVE RADIUS and press the
EDIT ALARM menu key.
3. Enter the new value you want, then press ENTER, or CLEAR to
leave the value unchanged.
(NAVIGATION OPTIONS)
g eod et ic d at u m
The geodetic datum option contains all referenced datums according to
Defense Mapping Agency publications.
To change the datum reference your 941X is using, press the EDIT menu
key at this option and use the up/ down cursor keys to scroll through the
alphabetic listing. When your choice is displayed, press ENTER. (The
complete listing of 941X datums is found at the end of this chapter, be-
"
(NAVIGATION OPTIONS)
cros s t rack fu ll
s cale
The STEERING screen cross-track display limits may be adjusted to suit
your needs, whether you are navigating in open waters or attempting to
maneuver through a tight channel.
Adjustments to the display limits (shown at the bottom of the screen)
enable you to monitor your progress in increments of feet or meters, if
you wish, as opposed to the normal settings of tenths of miles, tenths of
nautical miles or kilometers.
The format available to you depends on the selection made in the
DISTANCE/ SPEED UNITS setting under the DISPLAY OPTIONS
screen. The corresponding choices are:
DISPLAY OPTIONS SETTING
CROSS-TRACK OPTIONS
MI / MPH
NM / KNOTS
KM / KPH
1000 FT, 2000 FT, ½ MILE
1000 FT, 2000 FT, ½ N. MILE
200 Meters, 1KM, 2KM
Rev. D
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NOTE
CROSS-TRACK FULL SCALE
The
display formats apply only
STEERING
to the
screen, and not to the 3-D steer screen.
The options represent the entire distance limit on your screen, from
complete left to complete right. Therefore, a cross-track distance setting
of 1,000 feet will display 500 feet to either side of your track line, while a
choice of ½ mile will display limits of ¼ mile to either side, and so forth.
To change the setting, press the EDIT menu key and use the up/ down
cursor keys to scroll through the available choices. Press ENTER when
you are done, or CLEAR to leave the option unchanged. If necessary,
modify the DISPLAY OPTION setting to enable your choice of either
feet or meters in the cross-track display.
"
(NAVIGATION OPTIONS)
s t eer d is t
p recis ion
The STEER DIST PRECISION function offers an extra level of accuracy
to the distance-to-waypoint display on the STEERING and 3-D STEER
screens. Situated in the upper-left portion of the screens, the distance-to-
waypoint is normally displayed in tenths of miles or kilometers.
By changing the STEER DIST PRECISION option from NORMAL to
HIGH, the distance-to-waypoint display will increment in feet or meters,
once you have come within 1.0 mile or kilometer of the destination way-
point.
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To change the STEER DIST PRECISION option, press the EDIT menu
key and use the up/ down cursor keys to scroll among the choices of
HIGH or NORMAL. Press ENTER when you are done, or CLEAR to
leave the option unchanged.
"
Both steering information screens will now reflect your preference when
you are less than one mile or kilometer from your destination.
The 941X’s RECEIVER OPTIONS provide you with advanced control
Receiver
Op tion s
capability over several of the unit’s GPS and DGPS navigation functions.
When not using Differential GPS, you may notice that Speed-Over-
Ground readings obtained from the GPS satellite system are slightly er-
ratic, varying by up to several knots. The 941X’s SPEED AVERAGING
function can often improve the steadiness of these readings, at the ex-
pense of a slightly longer display reaction time when the speed changes.
GPS s p eed
averag in g
The time over which your speed is averaged by the 941X may be selected
with this function, with values between two and ten seconds available.
Averaging may also be turned OFF completely for the quickest possible
reaction time.
A longer averaging time is useful at lower speeds, where the highest ac-
curacy is required, such as when you want to trawl at a certain optimum
speed. You will see a slower-changing, more steady display of your speed,
with a high degree of accuracy. Shorter averaging times, however, will
give you a quicker-changing display of your speed, but with less accu-
racy.
Rev. D
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To change the speed averaging value:
"
1. Move the cursor arrow in front of the GPS SPEED AVERAGING
option and press the EDIT menu key.
2. Use the up/ down cursor keys to select an averaging time of two to
10 seconds—or OFF.
3. Press ENTER to make the change, or CLEAR to leave the value at it
previous setting.
You may change the speed averaging value at any time without affecting
other 941X navigation functions.
(RECEIVER OPTIONS)
b eacon
freq u en cy/
b eacon b au d
rat e
If your 941X either contains an internal beacon receiver or is interfaced
to an external Northstar beacon receiver, you can set the 941X to control
the beacon receiver automatically or control it manually yourself. Under
automatic control, the receiver scans for nearby beacon transmitters and
uses the one having the best signal for your area. It finds the beacon fre-
quency and data transfer (baud) rate, then receives data fully automati-
cally.
If you prefer, you can set the beacon frequency and baud rate manually
to tune in a particular beacon transmitter. (Refer to the “manual mode”
operation of the internal beacon receiver on page 75.) For normal opera-
tion, it is recommended that these controls be set to AUTO.
The beacon frequency can be set to any value between 283.5kHz and
325kHz. The baud rate should be set to AUTO, but can be manually set,
if necessary, to any of the four standard rates: 25bps, 50bps, 100 bps or
200 bps.
(RECEIVER OPTIONS)
d g p s op erat ion
This option allows you to enable or disable use of differential corrections
while navigating in areas where no DGPS signals are available (several
hundred miles from the nearest transmitter, for instance). When set to
DISABLED, the 941X ignores the use of DGPS signals, whether they are
from an internal or external source. For normal operation, it is recom-
mended that this setting be left at the factory default of ENABLED.
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(RECEIVER OPTIONS)
GPS d at a
t im eou t
This setting determines how long the 941X will continue to use existing
DGPS corrections if no new corrections are being received (due to bad
weather, extreme distance from beacon, etc.). If this time period elapses
with no new DGPS data received, the 941X reverts to standard GPS navi-
gation, and displays OLD CORRECTIONS as the DGPS status.
Under normal operating conditions, this “time-out” should be set to one
or two minutes to guarantee the highest accuracy. In poor weather con-
ditions, this value can be increased to a maximum of five minutes to ig-
nore occasional outages in the beacon reception (if a minor loss of
accuracy can be tolerated). The default setting is 60 seconds.
To change the “age of correction” timeout, use the up/ down cursor keys
to move the arrow at the left of the screen to DGPS DATA TIMEOUT:.
Press EDIT, then use the cursor keys to choose any value from 30 sec-
onds to five minutes, in 30-second increments.
"
NOTE
A period of 30 seconds is, in many cases, too short and can
lead to intermittent problems. Generally, one minute (the de-
fault value set at the factory) provides good navigation accu-
racy, and is best left unchanged.
Press ENTER to make your selection, or CLEAR to leave it unchanged.
Rev. D
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After this “timeout” period elapses with no DGPS data having been re-
ceived, the 941X will revert to navigating with normal GPS, the DGPS
display indicator (shown at left) will be turned off, and the “DGPS lost”
alarm will sound, if enabled (see “Alarms,” beginning on page 68). DGPS
navigation will resume automatically as soon as valid corrections are re-
ceived again.
(RECEIVER OPTIONS)
lowes t s at
elevat ion
NOTE
It is recommended that this option be left at the factory default
of 10°.
The LOWEST SAT ELEVATION option is used primarily in technical
applications where the 941X is tracking all visible satellites, regardless of
how low they are situated relative to the horizon. In those instances
where high-precision fixes are necessary, the advanced user can modify
this option to “hide” any low satellites, thereby preventing their use as
sources of GPS position information, and avoiding potential errors.
If needed, this option is adjustable from 0° to 25°, in 5° increments.
The 941X allows you to connect (or “interface”) directly with a variety of
Port Setup
Op tion s
external devices, such as autopilots, radars, depth sounders, computers,
etc.
Connection is made through any of three data transmission “ports” lo-
cated on the back side of the 941X: two NMEA ports and one RS-232
port. Each is capable of operating independently, thereby giving you the
flexibility of driving (or “talking to”) three separate devices simultane-
ously. The ports are also independently configurable to meet the specifi-
cations of most peripheral navigation equipment. This ensures a
customized setup for virtually any NMEA 0183-compatible device. Once
configured, the 941X will continuously send a stream of data to the de-
vice(s).
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Refer to “Programming the Output Ports,” on page 115, for detailed in-
formation on how to interface your 941X with other equipment.
To view your 941X’s serial number and hardware specifications, press
the STAR key until the USER CUSTOMIZATION screen is displayed.
Press the SERVICE INFORMATION menu key to display the following
screen:
Service Op tion s
s erial n u m b er
(SERVICE INFORMATION)
In addition to being affixed to the back of the unit, your 941X’s serial
number is permanently programmed into memory at the factory. Serial
numbers ending with the letter “D” indicate that the unit contains an
internal DGPS beacon receiver. Be sure to have your 941X’s serial num-
ber and software version available (see below) whenever contacting, or
corresponding with, your Northstar dealer or the factory.
Rev. D
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(SERVICE INFORMATION)
m ain b oard
s oft ver
This number indicates the revision level of your 941X’s operating soft-
ware program.
(SERVICE INFORMATION)
b eacon rx
s oft ver
If your 941X has an internal beacon receiver installed, this line will con-
tain a number indicating the software revision of the beacon receiver. If
none is installed, the line will be blank.
(SERVICE INFORMATION)
b eacon rx
s elf t es t
The 941X automatically self-tests the internal beacon receiver (if in-
stalled) each time the unit is powered up. If all test parameters are met,
this field will say PASSED. If the beacon receiver fails in any of the test
criterion, the message FAILED will be displayed. In many cases, the
cause of the failure is an open or shorted antenna cable, which can be
repaired in the field. If this is not the source of the failure, return the
941X to the factory for service.
(SERVICE INFORMATION)
g p s rx s oft ver
g p s rx s elf t es t
This displays the software revision being used by your 941X’s main GPS
receiver. If these lines are blank, the GPS receiver has not been tested
recently. Press the TEST GPS RX menu key and wait approximately 15
seconds for the test procedure to be completed. Once finished, the re-
ceiver’s revision number will be displayed, along with the message
PASSED in the GPS RX SELF TEST line at the bottom of the screen. If
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the message FAILED is displayed, return the 941X to the factory for
service.
(SERVICE INFORMATION)
keyp ad t es t
A built-in test feature allows you to verify the integrity of your 941X key-
pad. Each key you press here will be identified in the KEY PRESSED
display box. This function works for all but the POWER, CONTRAST
control, and SAVE/ MOB keys located to the left of the display screen
(pressing SAVE/ MOB during the keypad test will save a waypoint in-
stead of testing the key).
Press and hold the CURSOR up or down key until you return to the
SERVICE INFORMATION screen.
(SERVICE INFORMATION)
wirin g in fo
Press this menu key to display a listing of the 941X’s interface cable wir-
ing colors and their interface port functions. The wires are also num-
bered according to their respective positions in the interface connector.
A diagram of the connector pins is shown in Figure 11, on page 113. To
match the wires with their corresponding pin numbers, refer to Table 2
on page 114.
Rev. D
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Different regions of the world use various models for lat/ lon coordinates
on their charts, called “datum.” You should always be sure that your
941X is using the same datum as your charts.
Geod etic
Datum
Press the STAR key until you display the USER CUSTOMIZATION
screen, then press the NAVIGATION OPTIONS menu key. Move the
cursor down to GEODETIC DATUM and press EDIT. Use the up or
down cursor keys to scroll through the list of datums (organized alpha-
betically, as in the list below). When you come to the datum you desire,
press ENTER, or press CLEAR to leave the datum choice unchanged and
exit the edit function.
"
The following chart lists the datums available in your 941X:
delta
x
delta
y
delta z
ELLIPS.
ID
ADI_MN
ADI_E
DATUM NAME
ADINDAN Mean—Africa
CL1880
CL1880
CL1880
CL1880
CL1880
KRASS
INTL
-166
-165
-123
-128
-161
-43
-15
-11
204
206
220
224
205
45
ADINDAN—Ethiopia
ADINDAN—Mali
ADI_MA
ADI_SE
ADI_SU
AFG
-20
-18
ADINDAN—Senegal
ADINDAN—Sudan
-14
AFGOOYE—Somalia
AIN EL ABD 1970—Bahrain Island
ANNA 1 ASTRO 1965—Cocos Islands
ARC 1950 mean value
ARC 1950—Botswana
ARC 1950—Lesotho
-163
-251
-22
-90
-105
-108
-73
-105
-19
AIN
-150
-491
-143
-138
-125
-161
-134
-169
-147
-142
-160
-161
-158
-207
145
-2
ANA
AUSTR
CL1880
CL1880
CL1880
CL1880
CL1880
CL1880
CL1880
CL1880
CL1880
CL1880
CL1880
INTL
435
-294
-289
-295
-317
-295
-278
-283
-293
-300
-300
-299
52
ARC50_MN
ARC50_B
ARC50_L
ARC50_M
ARC50_S
ARC50_ZR
ARC50_ZM
ARC50_ZB
ARC60_MN
ARC60_K
ARC60_T
ASC
ARC 1950—Malawi
ARC 1950—Swaziland
ARC 1950—Zaire
ARC 1950—Zambia
-74
-96
-8
ARC 1950—Zimbabwe
ARC-1960 mean value
ARC 1960—Kenya
-7
ARC 1960—Tanzania
Ascension Island 1958
Astro Beacon "E" (Pacific Isl.)
-12
107
75
ABE
INTL
-272
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AB4
Astro B4 Sorol Atoll (Hawaiian Islands)
Astro Dos 71/ 4 (Atlantic Isl.)
Astronomic Station 1952
Australian Geodetic 1966
Australian Geodetic 1984
Bellevue (IGN)
INTL
INTL
114
-320
124
-133
-134
-127
-73
-116
550
-234
-48
-333
-494
-25
AD714
AS52
INTL
AG66
AUSTR
AUSTR
INTL
148
149
472
296
-318
90
AG84
-48
BEL
-769
213
304
136
-304
-108
150
BER
Bermuda 1957
CL1866
INTL
BOG
Bogota Observatory (Colombia)
Campo Inchauspe
307
-148
298
-136
-2
CMI
INTL
CA66
Canton Astro 1966
INTL
-375
-292
181
431
113
CAPE
Cape (South Africa)
CL1880
CL1866
CL1880
INTL
CC_MN
CARTH
CHAT
Cape Canaveral mean value
Carthage
-263
175
6
Chatham 1971 (S.W. Pac. Isl.)
Chua-Astro
-38
CHUA
CORR
INTL
-134
-206
-377
230
211
-87
-87
-104
-130
-86
-84
-117
-97
229
172
-29
Corrego-Allegre
INTL
-6
DJAK
Djakarta (Batavia)
B1841
INTL
681
-199
147
-98
-50
DOS68
EI67
DOS 1968 (S.W. Pac. Isl.)
Easter Island 1967
-752
111
INTL
EUR50_MN
EUR50_WE
EUR50_CY
EUR50_EG
EUR50_GB
EUR50_GR
EUR50_IR
EUR50_SA
EUR50_SI
EUR50_NF
EUR50_PS
EUR79
GAND
European 1950—mean value
European 1950—Western Europe
European 1950—Cyprus
European 1950—Egypt
European 1950—England
European 1950—Greece
European 1950—Iran
European 1950—Sardinia
European 1950—Sicily
European 1950—Norway and Finland
European 1950—Portugal and Spain
European 1979
INTL
-121
-120
-140
-151
-120
-130
-164
-120
-135
-120
-122
-119
50
INTL
-96
INTL
-101
-117
-96
INTL
INTL
INTL
-95
INTL
-132
-103
-88
-95
INTL
INTL
-97
INTL
-87
-88
-86
-133
84
INTL
-109
-98
INTL
Gandajika Base (Indian Ocean)
Geodetic Datum 1949
Guam 1963
INTL
-321
-22
GD49
INTL
209
259
-751
-86
-189
303
257
611
-229
-204
86
GUAM63
GUX
CL1866
INTL
-100
252
-73
-248
-209
46
Gux 1 Astro
HJOR
Hjorsey 1955—Iceland
Hong Kong 1963
INTL
HK
INTL
-156
214
289
506
208
191
-97
-271
836
734
-122
-435
-77
IND_TV
IND_BIN
IRE65
Indian (Thailand/ Vietnam)
Indian (Bangladesh/ India/ Nepal)
Ireland 1965
EVRST
EVRST
AIRYM
INTL
ISTS
ISTS 073 Astro 1969
JI61
Johnston Island 1961
Kandawala—Sri Lanka
Kerguelen Island (Indian Ocean)
Kertau 1948 (Malaysia)
KKJ (Finnish)
INTL
JAND
EVRST
INTL
787
-187
851
-231
124
KERG
145
-11
103
5
KERT
EVRSTM
FINN
KKJ
-78
-97
LC5A
L.C. 5 Astro (Caribbean)
Liberia 1964
CL1866
CL1880
CL1866
CL1866
CL1880
INTL
42
147
88
LIB64
-90
40
LUZ_P
LUZ_M
MAHE
MASI
Luzon—Phillipines
-133
-133
41
-77
-51
Luzon—Mindanao Island
Mahe 1971 (Indian Ocean)
Marco Astro—Salvage Islands
Massawa (Africa)
-79
-72
-220
-124
405
146
-58
-134
60
-289
639
31
MASS
B1841
CL1880
INTL
60
MERCH
MA61
Merchich (Africa)
47
Midway Astro 1961
912
-92
1227
122
MINA
Minna (Africa)
CL1880
-93
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NAH_O
Nahrwan—Masirah Island (Oman)
Nahrwan—United Arab Emirates
Nahrwan—Saudi Arabia
CL1880
CL1880
CL1880
INTL
-247
-249
-231
-2
-148
-156
-196
374
160
159
161
135
154
140
158
162
160
157
159
139
125
152
125
152
114
369
381
482
172
NAH_UA
NAH_SA
NAP
Naparima BWI (Trinidad and Tobago)
North American 1927—CONUS mean value
North American 1927—Western U.S.
North American 1927—Eastern U.S.
North American 1927—Alaska
North American 1927—Bahamas
North American 1927—San Salvador Island
North American 1927—Canada
North American 1927—Alberta and B.C.
North American 1927—East Canada
North American 1927—Manitoba and Ontario
North American 1927—N.W. Terrs. & Sask.
North American 1927—Yukon
North American 1927—Canal Zone
North American 1927—Caribbean
North American 1927—Central America
North American 1927—Cuba
NAD27_MN
NAD27_WU
NAD27_EU
NAD27_AK
NAD27_BH
NAD27_SS
NAD27_CN
NAD27_AB
NAD27_EC
NAD27_MO
NAD27_NE
NAD27_YK
NAD27_CZ
NAD27_CR
NAD27_CA
NAD27_CU
NAD27_GR
NAD27_MX
NAD83
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
CL1866
GRS80
INTL
-8
176
-8
175
-9
179
-5
172
-4
178
1
165
187
188
190
184
188
181
201
178
-10
-7
-22
-9
4
-7
0
-7
0
194
178
-9
North American 1927—Greenland
North American 1927—Mexico
North American 1983
11
195
190
0
-12
0
130
0
OB1966
Observatorio 1966 (Atl. Isl.)
-425
-130
61
-169
110
81
OEG
Old Egyptian
HELM
CL1866
CL1866
CL1866
CL1866
CL1866
CL1880
AIRY
-13
OHW_MN
OHW_HW
OHW_KA
OHW_MA
OHW_OA
OMAN
Old Hawaiian—mean value
-285
-279
-290
-290
-284
-1
-181
-183
-172
-190
-181
224
431
434
434
425
434
127
42
Old Hawaiian—Hawaii
89
Old Hawaiian—Kauai
45
Old Hawaiian—Maui
65
Old Hawaiian—Oahu
56
Oman
-346
375
371
371
384
370
-307
185
16
OSGB_MN
OSGB_E
Ordin. Survey of Gr. Britain 1936—mean value
Ordin. Survey of Great Britain 1936 —England
Ordin. Survey of G. B. 1936—Isle of Man, Wales
Ord Surv of G.B. 1936—Scot. & Shetlnd Islands
Ordinance Survey of Great Britain 1936—Wales
Pico De Las Nieves—Canary Islands
Pitcairn Astrological—1967
-111
-112
-111
-111
-108
-92
165
196
175
188
183
243
169
171
159
175
173
72
AIRY
OSGB_IM
OSGB_SSI
OSGB_WL
PDLN
AIRY
AIRY
AIRY
INTL
PA67
INTL
PSC63
Provisional S. Chilean 1963
INTL
93
PSA56_MN
PSA56_BO
PSA56_NC
PSA56_SC
PSA56_CO
PSA56_EC
PSA56_GY
PSA56_PR
PSA56_VN
PRICO
Provisional S. American 1956—mean value
Provisional S. American 1956—Bolivia
Provisional S. American 1956—N. Chile
Provisional S. American 1956—S. Chile
Provisional S. American 1956—Columbia
Provisional S. American 1956—Ecuador
Provisional S. American 1956—Guyana
Provisional S. American 1956—Peru
Provisional S. American 1956—Venezuela
Puerto Rico
INTL
-288
-270
-270
-305
-282
-278
-298
-279
-295
11
-376
-388
-390
-442
-371
-367
-369
-379
-371
-101
22
INTL
INTL
INTL
INTL
INTL
INTL
INTL
INTL
CL1866
INTL
QUAT
Qatar National
-128
164
94
-283
138
-948
-65
42
QORN
Qornoq (Greenland)
INTL
-189
-1262
9
REUN
Reunion (Indian Ocean)
INTL
ROME
Rome 1940
INTL
-225
170
-203
-355
616
-57
SDOS
Santo (DOS) (S.W. Pacific Isl.)
Sao Braz (Atl. Isl.)
INTL
84
SBRAZ
INTL
141
16
53
SHILL
Sapper Hill 1943
INTL
74
SCHW
Schwarzeck (Namibia)
B1841N
SA1969
97
-251
-41
SA69_MN
South American 1969—mean value
1
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SA69_AG
SA69_BO
SA69_BR
SA69_CH
SA69_CO
SA69_EC
SA69_GY
SA69_PA
SA69_PR
SA69_TT
SA69_VZ
SASIA
South American 1969—Argentina
South American 1969—Bolivia
South American 1969—Brazil
South American 1969—Chile
South American 1969—Colombia
South American 1969—Ecuador
South American 1969—Guyana
South American 1969—Paraguay
South American 1969—Peru
South American 1969—Trinidad and Tobago
South American 1969—Venezuela
South Asia
SA1969
SA1969
SA1969
SA1969
SA1969
SA1969
SA1969
SA1969
SA1969
SA1969
SA1969
FS1960M
INTL
-62
-61
-60
-75
-44
-48
-53
-61
-58
-45
-45
7
-1
2
-37
-48
-41
-44
-36
-44
-47
-33
-44
-33
-33
-26
314
-38
-46
664
662
665
661
-609
-36
-39
4.5
-2
-1
6
3
3
2
0
12
8
-10
-249
167
691
481
483
481
478
438
391
52
0
SEBAS
Southeast Base
-499
-104
-689
-128
-123
-128
-135
-632
51
SWBAS
TIMB
Southwest Base
INTL
Timbalai 1948 (Malaysia)
Tokyo mean value
EVRST
B1841
TOK_MN
TOK_JP
TOK_KR
TOK_OK
TA68
Tokyo—Japan
B1841
Tokyo—Korea
B1841
Tokyo—Okinawa
B1841
Tristan Astrological 1968 (S. Atl.)
Viti Levu 1916 (S.W. Pac. Isl.)
Wake-Eniwetok 1960
INTL
VL16
CL1880
HOUGH
WGS-72
WGS
WE60
101
0
WGS72
WGS 1972
WGS84
WGS 1984
0
0
0
Zanderij (S. America)
INTL
-265
120
-358
Table 1—Datum List
Rev. D
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9
In s tallation an d In terfacin g
Mounting the 941X 100
Wiring the 941X System 102
GPS Antenna Location 104
DGPS Antenna Coupler (ACU) 108
Interfacing the 941X 112
Programming the Output Ports 115
RS-232 Port 126
This section includes all the information needed to install
your 941X and interface it to other equipment on your
boat.
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Proper installation of your Northstar 941X receiver is of utmost impor-
tance to accurately receive and effectively use GPS signals under a wide
variety of weather conditions. To get the best performance from your
Northstar, we strongly recommend that you have an authorized North-
star dealer install it for you. However, if you prefer to perform the in-
stallation yourself, please follow these instructions carefully.
Mounting the
941X
The following points should be considered before proceeding with your
installation:
# location of unit
# electrical power and wiring
# antenna location and installation
# grounding the entire system
# testing and monitoring system performance
It is recommended that the unit be bench tested prior to installation on
your boat. This not only insures that the equipment is fully operational,
but it allows the GPS receiver to collect its almanac and ephemeris data
for the installed location, resulting in less installation time spent on the
vessel.
Choose a mounting location for the 941X that allows good visibility of the
screen, is within comfortable reach, and provides a reasonably direct
path for running the required electrical cabling.
The majority of installation problems are caused by shortcuts taken with
system cables. Assemble connectors carefully; don’t make sharp bends;
leave service and drip loops; tie-wrap the coaxial antenna cable to keep it
secure.
Your Northstar 941X is shipped complete and ready to install. You will
need special tools for assembling the coaxial cable connectors, as indi-
cated on page 105.
941X s ys t em
com p on en t s
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The shipping carton contains the following components:
• the 941X
• GPS antenna
• 25’ coaxial antenna cable (for passive-patch antennas; 50’ sup-
plied with optional active-patch antenna)
• beacon receiver Antenna Coupling Unit (ACU) (for units with
internal differential GPS receiver only)
• 10’ interface cable
• 10’ power cable
• flush-mount drilling template
• sunshield
• this Reference Manual
• connectors and parts kit
Save all packing material in the event it is necessary to return the unit to
the factory for repair or evaluation. Your 941X should only be shipped in
a properly designed carton with packing material.
The 941X houses the GPS receiver, optional beacon receiver, computer,
power supply, lights, controls and the specially-coated display screen.
The mounting location should be chosen carefully before any drilling or
cutting takes place. Be sure you have easy access to the control panel’s
keys and can clearly see the display from your normal vantage point
when navigating your boat. Even though the display screen contains an
effective anti-reflective coating, choose a location where glare from win-
dows or other bright objects will be minimized. Refer to the dimensions
in Figure 13 for planning your installation.
p lacem en t of t h e
941X
Whether you’re flush-mounting or yoke-mounting the unit, allow at least
2½ " clearance at the rear for cables and connectors. For yoke-mounts,
leave ample room (usually 2") all around the sides and top to avoid
crowding the unit. (See Figure 2 for yoke-mount drilling requirements.)
Though the unit itself is waterproof, the connectors at the back of the
unit are not impervious to corrosion from saltwater spray. Protect your
Northstar investment from prolonged exposure to the elements by
mounting it in a relatively dry area, if possible. At the end of the day,
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wipe the unit dry, especially the rear connectors. When not in use, cover
the 941X with the sunshield to protect it from excessive heat.
Figure 2—Yoke Mount Drilling Dimensions
Your Northstar is designed with an internal fusible link to protect against
faulty power wiring. The link consists of a short length of 30 AWG wire
located on the I/ O board. If this link becomes open-circuited, carefully
check all power wiring, especially the white and black wires on the power
cable.
Wirin g th e 941X
Sys tem
Replacement of the fusible link should be performed only by a qualified
electronics technician. Access to the link is gained by removing the 10
outer case screws to open the 941X, then removing the 4 computer board
screws and lifting the computer board out to expose the I/ O board below.
The link should be replaced with another short length of 30-gauge wire.
The 941X is a negative-ground system that is reverse-polarity protected:
an internal fuse prevents damage to sensitive components.
elect rical p ower
req u irem en t s
The 10-foot power cable wires must be connected as follows:
+
• Red → Positive ( ) 10–40VDC
• Black → Negative (–)
• White → Ground
• negative ground only
• 14-gauge connecting wire (recommended for runs of 15 feet or
more)
• 16-gauge minimum allowed for runs up to 15 feet
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We strongly recommend (as a good safety practice) that your 941X be
connected to an external circuit breaker or fuse located near the battery
or breaker box. The internal fuse is designed to protect the 941X itself;
the external fuse or breaker is intended to protect the vessel wiring and
prevent electrical fires. The power wiring should be connected directly to
the battery when possible for optimum noise immunity.
J1
J2
J3
J4
J5
Power Connector (3 wire)
Main I/ O Interface Connector (18-wire)
Auxiliary (future expansion—10 wire)
GPS Antenna Connector (BNC)
DGPS Antenna Connector (UHF)
Figure 3—Rear Connectors
The 941X should be connected to a source of 10- to 40-volt electrical
power, using at least 16-gauge wire. A 10-foot power cable is supplied
with your unit, and should be sufficiently long for most installations. If it
is necessary, however, to lengthen the power cable, you may extend it to
a maximum of 25 feet without adversely affecting the operation of the
unit.
p ower wirin g
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Three antennas choices are available for your 941X: two for reception of
GPS-only signals (standard #AN145 and “active” #AN150), and one to
receive both GPS and DGPS signals (#AN190 combo antenna).
Antenna
Location
The antenna is a vital link between the 941X receiver and the outside
world. Aesthetics and easy access should be secondary to providing
strong and reliable GPS signals to the 941X receiver. You should select a
location for the antenna which meets the following requirements:
# The antenna should have a reasonably clear view of the horizon, but
be no higher than necessary (side-to-side motion of the antenna
caused by rolling of the vessel may degrade your SOG and COG
readings);
# The antenna must be out of the radiation plane of any on-board ra-
dar sets;
# The antenna must be lower than any INMARSAT communications
antenna;
# The antenna should be as far as possible from other high-power
transmitting antennas;
# Watch out for electromagnetic “shading” of antennas from rigging,
other vessels, shoreline buildings, etc. Secure the cable well (the
center conductor is solid wire).
Whereas a loran antenna should be mounted high on the vessel for best
performance, the GPS-only antenna should be mounted as low as possi-
ble and out in the open to avoid “shading” (placement of the antenna
where it is partially obscured by another object from the signals it must
receive). Don’t mount the antenna on top of a tower or mast. Often the
bow or stern will provide a location where shading is minimized, while
serving to keep the antenna low. Be sure that any directional L-band
transmitting antennas (such as radar or satellite communication anten-
nas) can never point at the GPS antenna—its preamplifier is quickly de-
stroyed by such radiation.
g p s -on ly
an t en n a locat ion
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3.00
ANTENNA
.91
O-RING
ADAPTER
1.82
CAPTIVE SCREW
Figure 4—941X GPS-Only Antenna (AN145 & AN150)
7.00
2.5
TNC
3.5
Figure 5—941X Combo GPS/DGPS Antenna (AN190)
Tools needed:
1) flat-bladed screwdriver
2) knife blade
m ou n t in g t h e
GPS-on ly
an t en n a
3) Amphenol crimp tools.
The RG-59 cable supplied with your 941X has one TNC connector at-
tached to the antenna-end of the coax. Connection to the antenna itself
involves the following steps:
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1. Remove the antenna base by loosening the four captive screws
in the base.
2. Screw the base onto the top of the antenna mount (standard 1"-
14 marine thread).
3. Feed the open end of the supplied coax cable down through the
antenna base and through the hollow core of the antenna
mount.
4. Affix the TNC connector-end of the coax to the mating connec-
tor inside the upper half of the GPS antenna.
5. Align the upper half of the antenna with the bottom half and
tighten the four screws. Be careful not to over-tighten the
screws, as this may deform the watertight seal between the two
antenna halves.
Supplied with your antenna is a length of RG-59 coaxial cable (25 feet
with #AN145 passive antenna, and 50 feet with the optional #AN150 ac-
tive and #AN190 combo antennas).
an t en n a wirin g
Cable length for the GPS-only passive antenna must not exceed 25 feet. If
a longer cable run is necessary, use either the Northstar “active” or
“combo” antenna for minimum lengths of 50 feet, up to a maximum of
100 feet. (Runs between 25 and 50 feet require either the active or
combo antenna and the minimum 50-foot length of cable. The extra
footage may be coiled up, but not removed.)
For applications with grounding problems, or where optimum portability
is required, or when only a single antenna is desired, a combination
GPS/ DGPS antenna is available, part #AN190 (see Figure 5 on page
105). This “combo” antenna provides for an easier and better-looking
installation. In many cases, the loop antenna design improves the noise
rejection of signals interfering with differential signals. However, like the
“active” GPS antenna, the combo antenna must be used with a minimum
of 50, and no more than 100, feet. Any unused length must be coiled up;
do not cut it to less than 50 feet!
com b o
GPS/ DGPS
an t en n a
The cable “splitter” box supplied with the AN190 combo antenna should
be located near the 941X for convenience, but may be situated virtually
anywhere along the length of the maximum 100 feet of RG-59 GPS cable,
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without appreciable signal loss. However, the splitter is not weatherproof
and should be placed in a protected area where it will not be subjected to
direct water splash or spray.
The combo antenna should be located where it has a clear view of the ho-
rizon, but is not the highest point on the vessel. Keep the antenna at least
six feet away from objects that can “shade” GPS or differential signals.
com b o an t en n a
locat ion
Avoid tight bends when installing any antenna cable. Be sure to fasten
the cable along its length to avoid chafing or whipping of any kind.
GPS an t en n a
cab les
After the antenna has been mounted and the cable has been cut to
length, install the supplied BNC connector at the other end (refer to Fig-
nector may be made with a commonly available, high-quality crimping
tool designed for use with BNC connectors.
Be sure the BNC connector is properly installed—most system failures,
whether continuous or intermittent, can be traced to poor connector in-
stallation.
1) Strip cable jacket to the following dimensions (in inches), as illus-
trated in Figure 6: a=0.57, b=0.34, c=0.14, d=0.43. Do not nick the
center conductor.
Figure 6—Stripping the Coax Cable Jacket
2) Figure 7: Slide outer ferrule on as shown. Slightly flare the end of ca-
ble braid, as shown, to facilitate insertion into inner ferrule.
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Figure 7—Flared Cable Braid
3) Place center contact onto center conductor so that it butts against the
cable dielectric. Crimp the contact in place using Amphenol tool han-
dle #227-944 and Cavity B of Die Set 227-980-3.
4) Figure 8: Install cable assembly into body assembly so inner ferrule
slides over dielectric and under braid. Push cable assembly forward
until contact seats in insulator. Slide outer ferrule over braid and up
against connector body. Crimp outer ferrule using Cavity A of tools
specified above.
Figure 8—Completed BNC Connector
If poor GPS SNR readings are obtained after the 941X has been running
for several minutes, check that you have the proper length of cable
matched to the type of antenna (active, passive, or combo), verify the
quality of the antenna location, and the quality of the connectors.
The Northstar 8410 Antenna Coupling Unit (ACU) supplied with the
Differential GPS-equipped 941X must be used in all differential GPS an-
tenna installations, except in cases where the AN190 Combo GPS/ DGPS
antenna is used. Though similar in appearance to other Northstar ACUs,
only the one labeled “8410” will work with your internal DGPS beacon
receiver. The ACU also serves as a sturdy mounting base for the DGPS
whip antenna.
DGPS An ten n a
Cou p ler (ACU)
The ACU consists of two pieces. The circuitry is sealed in a rugged, wa-
terproof, fiberglass polycarbonate body, the upper end of which is
threaded to accept a standard 4-foot whip antenna. A large female thread
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is molded into the lower portion, or base, of the ACU body into which the
upper half is secured (see Figure 9 on page 110). The bottom of the base
is threaded (1"–14) to mount onto the antenna mast or onto a standard
deck mount. A gasket and rubber O-ring provide weathertight sealing at
the ACU base.
The ACU connects to the receiver by a single 25-foot length of RG-58U
coaxial cable which carries signals to the beacon receiver and DC power
to the ACU amplifier. The cable passes up through the hollow ACU base
and connects to the PL-259 (UHF) connector at the bottom of the ACU
(see Figure 10 on page 111 for UHF connector preparation). Note: This
connection must be made before the ACU is screwed into its base.
The grounding system is an equal partner with the antenna in producing
quality signals for the 941X DGPS beacon receiver. Essentially, the
ground system provides a secure connection to a large electrical mass;
ideally, the earth itself. On a vessel, this means establishing electrical
contact with the sea. On a steel vessel, a good connection to the hull or
steel pilothouse is sufficient. Wood or fiberglass vessels require a metal
ground plate. If the metal ground plate is impractical, the engine block or
the negative (–) battery terminal can sometimes be used, but only as a
second choice.
g rou n d in g
Lack of proper grounding can adversely affect beacon signal strength, as
well as SNRs, and is the most common source of problems with beacon
antenna installations. The 8410 ACU has a separate black ground wire
inside the coupler base. This wire is the AC signal ground connection
from the antenna input circuit. The purpose of bringing it out is to make
available a separate signal ground path.
Other electrical equipment onboard can cause large amounts of electrical
noise, even at points that appear well-grounded. Try several ground
points (ground plate, vessel ground, engine block, etc.) to determine
which works best under different conditions.
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Figure 9—ACU Assembly
WARNING
WHENEVER ANY ANTENNA IS DISCONNECTED FROM ON-BOARD
EQUIPMENT, BE SURE TO GROUND THE ANTENNA SHIELD IN
ORDER TO DISCHARGE EXTREMELY LARGE STATIC VOLTAGES
THAT CAN QUICKLY BUILD UP ON AN UNGROUNDED ANTENNA
SYSTEM. THESE VOLTAGES ARE HAZARDOUS TO PERSONNEL
AND EQUIPMENT!
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Both ends of the differential beacon receiver antenna cable terminate in
UHF connectors. Follow the assembly instructions in Figure 10 for pre-
paring UHF connectors. For best results, coat these connectors with sili-
cone gel to retard corrosion.
d ifferen t ial GPS
an t en n a cab le
con n ect ors
Figure 10—PL 259 (UHF) Connector
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The Northstar 8410 differential beacon receiver antenna should be
mounted as high as conveniently possible (but not at the highest point)
and as far away as possible from other antennas. If you have several pos-
sible antenna locations, you may evaluate each by operating the 941X
with the DGPS antenna temporarily mounted in each location. The best
location is one providing the lowest “NOISE” count (atmospheric im-
pulse noise generated by thunderstorms and other conditions) and high-
est Signal-to-Noise Ratio (SNR). Both values may be viewed using the
DGPS STATUS information screen accessed from the main GPS
POSITION screen, as seen on page 26.)
DGPS an t en n a
m ou n t in g
Another major concern, precipitation static (called “P-static”), must be
addressed when installing the antenna. P-static generally appears only
during rain or snow; consequently, it can be easily overlooked during in-
stallation.
Much like a loran antenna, the effects of P-static are minimized if the
beacon antenna is mounted so that it is not the highest metallic object on
the vessel. The highest metal object acts much like a lightning rod, at-
tracting tiny static discharges in the atmosphere. If the beacon receiver
antenna is the highest object, these discharges can totally override the
beacon signals and cause poor operation in bad weather. The optimum
antenna location is high and clear for fair-weather operation, but below
the top of a metal mast or other antenna for best foul-weather operation.
On sailing vessels, the ACU might be mounted on top of a low mast, or
on the stern rail if no other suitable location is available.
The 8410 beacon ACU can be mounted on a standard marine antenna
mount (one inch diameter, 14 threads per inch).
The 941X is easily interfaced to other equipment as described below.
NMEA 0183 is the most common interface data format used with 941X
installations. It is a widely-accepted standard of data transfer between
most all types of marine electronics today, enabling completely different
instruments to “speak” a common language.
In terfacin g th e
941X
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The 941X has two programmable NMEA input/ output ports and one RS-
232 input/ output port that you can customize for outputting data to
other instruments, and two ports for inputting data from other devices.
(PORT SETUP OPTIONS)
con n ect or p in
wirin g
A list of wire connections for the interface connector is built-into the
941X’s PORT SETUP OPTIONS screen, accessed from the USER
CUSTOMIZATION menu. Press the WIRING INFO menu key to display
the following screen:
Figure 11—Interface Connector (mating side)
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Description
NMEA PORT 1 INPUT A
NMEA PORT 1 INPUT B
NMEA PORT 1 INPUT GROUND
NMEA PORT 1 OUTPUT A
NMEA PORT 1 OUTPUT B
NMEA PORT 1 OUTPUT GND
NMEA PORT 2 INPUT A
NMEA PORT 2 INPUT B
NMEA PORT 2 INPUT GROUND
NMEA PORT 2 OUTPUT A
NMEA PORT 2 OUTPUT B
NMEA PORT 2 OUTPUT GND
RS-232 GROUND
Wire Color
Pin
3
BROWN
BLUE
WHITE w/BLUE STRIPE
VIOLET
1
4
12
7
GRAY
BLUE w/WHITE STRIPE
WHITE w/BROWN STRIPE
BROWN w/WHITE STRIPE
WHITE
8
6
2
5
YELLOW
15
11
10
17
16
18
9
ORANGE
BLACK
TAN
RS-232 INPUT
GREEN
RS-232 OUTPUT
RED
EXT. GND / FOIL DRAIN
EXTERNAL SAVE IN
WHITE/ORANGE & SHIELD
ORANGE w/WHITE STRIPE
PINK
13
14
200 PPNM OUT
(Pulses Per Nautical Mile)
Table 2—Interface Connector Pins
The Northstar 941X provides an open-collector transistor output (on pin
14) which is programmed to produce 200 pulses per nautical mile for
those devices requiring this output.
200 p p n m
ou t p u t
The emitter of the NPN transistor is connected to ground, and the col-
lector connects to the output pin side (see block diagram in Figure 12 on
page 115). The output can sink 100mA and can withstand a maximum
positive voltage of 50 volts.
If the output connects to a highly inductive device, such as a relay, a
spike suppression diode should be connected across the load. Cathode
connects to the power side of the device and anode connects to the out-
put pin side.
The output produces a negative pulse 80ms wide and supports speeds
from zero to 100 knots (clamps at 100kt).
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Figure 12—200 PPNM Output Block Diagram
Each output port can be programmed to meet most any special require-
ments of devices that conform to the NMEA 0183 data format specifica-
tion. The SETUP function described below allows the selection of the
specific 0183 sentences that will be transmitted by the 941X.
Prog ram m in g
th e Ou tp u t
Ports
Press the STAR key until you see the USER CUSTOMIZATION menu.
Press the menu key marked PORT SETUP OPTIONS, then press the
PORT 1 SETUP or PORT 2 SETUP key.
A list of data format control options is displayed:
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Check the installation instructions for the equipment to which you are
interfacing for any special requirements. The Northstar factory settings
will be adequate for most peripheral equipment, but the following op-
tions are available, if needed:
PARAMETER
OUTPUT FORMAT:
(see below)
OPTIONS
choose NMEA 0180, NMEA 0183,
DATAM CDX, RAY 0183 or NONE
NMEA 0183 Talker ID:
(see page 120)
choose GP, LC, or I I, to make
the 941X look like a GPS receiver,
Loran-C receiver, or an “inte-
grated instrument”
NMEA 0183 lat/lon precision:
(see page 121)
choose hundredths of minutes,
thousandths of minutes, or ten-
thousandths of minutes
OUTPUT RATE:
(see page 122)
choose 2 to 999 seconds for the
interval at which data is sent to
the external device
NMEA 0183 waypoint ID as:
(see page 122)
choose NAME or NUMBER for the
identifier of waypoints sent to the
external device
NMEA 0183 checksums:
(see page 122)
choose ON or OFF for compatibil-
ity with some older devices
Table 3—Port Setup Options
(PORT 1 / PORT 2 SETUP)
ou t p u t form at
The 941X will output navigation data in any of several standard formats
(or one user-customizable sequence), as required by the receiving, or
“listener” device. Upon pressing the EDIT menu key at this option, then
the up/ down cursor arrows, you’ll find the following choices available to
you: NMEA 0180, 0183 V2.1, DATAMARINE CDX, 0183 RAY, and
NONE. Designate the required format and press ENTER.
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(NMEA) 0180 is an infrequently-used format, developed in the late
1970’s and is required by many older autopilots.
0183 V2.1 is the most popular interfacing format and is used by most
autopilots, radars, plotters and other equipment.
After pressing ENTER to select 0183 as the output format, you will be
presented with a list of all 0183 sentences which may be individually
turned on or off.
The 1.5 sentences (BWC, GLL, and RNN) enable the 941X to be back-
ward-compatible with marine equipment previously designed for this
earlier version of 0183. Details for using the 0183 format are given in the
following section, “NMEA 0183 and RAY 0183 sentences,” on page 118
DATAMARINE CDX is required by Datamarine’s cross-track error indi-
cators, the latest of which display distance and bearing to your waypoint.
0183 RAY is used when transmitting/ receiving position information
to/ from Raytheon equipment. It uses Raytheon’s non-standard NMEA
0183 checksum, where, on output, the checksum is not included, and on
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input to the 941X, the checksum is ignored. (It should be noted that, with
the checksum ignored on input, there is a possibility of the 941X receiv-
ing contaminated NMEA data when it is connected to an external Ray-
theon loran.) Format is supported on PORT 1 and PORT 2.
The setting NONE is used when the 941X is not connected to an external
device.
(PORT 1 / PORT 2 SETUP)
NMEA 0183 an d
RAY 0183
NMEA 0183 is perhaps the most widely-accepted standard of data
transfer used in marine electronics devices today. It enables GPS and lo-
ran navigators, for instance, to “talk” to plotters, radars, charting in-
struments and other electronics by means of a common “language.”
s en t en ces
When either NMEA 0183 or RAY 0183 is selected as the output format
(after pressing the EDIT menu key) and ENTER is pressed, a screen is
displayed showing all of the available NMEA 0183 sentences that will be
output by the 941X.
"
Some devices cannot handle all of these sentences, so you may use this
screen to customize the output by turning individual sentences ON or
OFF. In general, you might want to turn ON only those sentences used
by the particular equipment to which you are interfacing the 941X. (See
Table 4 on the next page for a listing of NMEA 0183 sentence identifier
meanings.)
To modify the 941X’s NMEA 0183 sentence output format, follow the
above steps to display the 0183 sentences. Three-letter abbreviations
identify each sentence and are listed alphabetically. The sentences that
"
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will be output are followed by the word ON. Those that will not be output
are followed by two dashes, signifying that they are turned OFF.
1. Move the cursor arrow to the sentence you wish to change and
press the EDIT menu key.
2. Use the up/ down cursor keys to toggle the sentence ON or off
(dashes) and press ENTER to make your selection, or CLEAR to
leave it unchanged.
3. Repeat for each sentence requiring modification. Press the
RETURN menu key to go back to the PORT SETUP screen when
you are done.
If you wish to set all sentences to the factory defaults for recommended
output, press the SAFE RESET menu key.
The ALL OFF menu key enables you to conveniently turn off all sen-
tences in the event you wish to then turn on only a select few for output.
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The meaning of the NMEA 0183 three-letter identifiers are:
0183
MEANING
Autopilot Sentence “B”
IDENTIFIER
APB
BOD
BWC
GGA
GLC
Bearing to Destination
Bearing & Distance to Wpt. (Great Circle)
GPS Fix Data
Geographic Position, Loran-C
Latitude/Longitude
GLL
GSA
GSV
HSC
RMA
RMB
RMC
RNN
VTG
GPS DOP and Active Satellites
GPS Satellites In View
Heading Steering Command
Recommended Min. Sentence A
Recommended Min. Sentence B
Recom. Min. Specific GPS/Transit Data
Navigation Route
SOG/COG
WCV
WPL
XTE
Waypoint Closure Velocity (SOA)
Waypoint Location
Cross-track Error
ZDA
Estimated Time of Arrival
Time-To-Go
ZTG
Table 4—NMEA 0183 Sentence Identifiers
(PORT 1 / PORT 2 SETUP)
NMEA 0183
t alker ID
Part of the NMEA 0183 standard requires that the equipment you are
interfaced to—the “listener”—know what type of device is transmitting
the data. The talker ID tells the listener that it is receiving information
from a navigation source (the 941X) and not a communications or sensor
device, which transmit completely different—and therefore unusable—
forms of data.
The “talker ID” enables you to configure the 941X’s output data to tell the
listener it is receiving data from a loran (LC) or GPS (GP) navigator, or
Integrated Instrumentation (II). The choice you make depends on what
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the listener device is expecting. Check the listener device’s instruction
manual to determine which “talker ID” codes it will respond to.
Use the EDIT menu key, then scroll through the three choices using the
up/ down cursor arrow keys to make your choice. Press ENTER when
done.
The interfaced equipment will then receive the 0183 data in the correct
nav-source format.
(PORT 1 / PORT 2 SETUP)
NMEA 0183
lat / lon p recis ion
For added versatility in communicating with a variety of other devices,
you can control the level of precision of the 0183 position information as
it’s output by the 941X.
Using the EDIT menu key and the up/ down cursor keys, you’ll see the
display change from:
•
•
•
XX.XX ’ (lat/ lon precision to two decimal places / hundredths of
minutes / or 60 feet) to
XX.XXX ’ (three decimal places / thousandths of minutes / or 6
feet), to
XX.XXXX ’ (four decimal places / ten-thousands of minutes / or
roughly ½ foot).
The factory default is .XXX (thousandths of minutes).
NOTE
Precision output to three or four decimal places does not mean
that your 941X navigates with such accuracy, unless it is using
DGPS. Position information can be output and displayed to
four decimal places, but your actual ability to navigate to such
a precise point is limited by the accuracy of the Loran and GPS
systems (see “Comparing GPS and Loran,” on page 5). There-
fore, specifying more decimal places in the data output does
not result in greater navigating accuracy.
The choice you make is dependent upon the equipment to which you are
outputting NMEA data. The 941X conforms to the NMEA version 2.10
standard, but is also compatible with version 1.50. Equipment typically
benefiting the most from three and four decimal places of precision are
electronic and pen plotting devices. However, most all older devices de-
signed to operate with the original 0183, and other formats, can only
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function with two-place precision. Refer to the manufacturer’s instruc-
tions for how many digits of precision are required for that particular
device.
(PORT 1 / PORT 2 SETUP)
ou t p u t rat e
The 941X defaults to a two-second update interval for data transmission.
There are some applications where a longer update period is required,
and the 941X allows you to increase that span to 999 seconds.
(PORT 1 / PORT 2 SETUP)
NMEA 0183
wayp oin t ID as
Many new marine electronic devices (such as radars and electronic plot-
ters) can display your waypoint names, if they are output by the 941X.
If your peripheral equipment has this capability, change the WAYPOINT
ID AS field from NUMBER to NAME, using the EDIT menu key, then
the up/ down cursor arrow keys. Press ENTER. The listening device will
now display your six-character waypoint names.
NOTE
Be sure to verify this capability in the listening device before
WAYPOINT ID AS
changing the
field. Most older equipment
won’t understand this identifier, and using it may cause prob-
lems with the display of your waypoint information.
Certain older devices may not accept sentences containing the NMEA
0183 checksum that is output by the 941X. In such cases, the device may
not operate properly, if at all.
n m ea 0183
ch ecks u m s
If you encounter difficulty when interfacing to older equipment, the 941X
offers you the flexibility of turning off the NMEA 0183 checksum. Move
the cursor to NMEA 0183 CHECKSUMS, press the EDIT menu key,
and use the up or down cursor key to change the setting from ON to
OFF. Press ENTER, then RETURN when you are done.
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If you presently own a Northstar 800 series loran, you may connect it to
your 941X to serve as an ideal source of Loran-C TDs and previously-
stored waypoint locations. Use the appropriate pin/ wire connections and
the 800’s setup sequence, each listed below, to initialize the data output
to be received by the 941X. Port 1 or Port 2 of the 941X, or A or B of the
800, may be used. Wire colors refer to the 941X’s interface cable.
con n ect in g t o a
Nort h s t ar 800
s eries loran
800 OUTPUT
PORT A
Pin 12
$ CONNECT TO EITHER %
941X PORT 1
941X PORT 2
brown (#3)
blue (#1)
white w/ brown stripe (#6)
brown w/ white stripe (#2)
Pin N
Table 5—Connection to Northstar 800 Port A
800 OUTPUT
$ CONNECT TO EITHER %
PORT B
Pin 7
941X PORT 1
941X PORT 2
brown (#3)
blue (#1)
white w/ brown stripe (#6)
brown w/ white stripe (#2)
Pin H
Table 6—Connection to Northstar 800 Port B
To configure the 800 for correct output format, execute COMMAND 83
for output port A, or COMMAND 84 for output port B. Press the lower
SELECT button until PRINTER 3 appears in the lower display, and press
ENT. Then enter the following sequence to program the output parame-
ters:
"
AT THIS
PROMPT
SET UP
INTERVAL
ITEM 1
PRESS
TO OUTPUT THIS DATA TO 941X
149 (ENT) 0183 output format (8 bits, no parity, 4800 baud)
1 (ENT) 1 second output rate
13 (ENT) include GTD sentence in output (Loran-C TDs)
26 (ENT) waypoint location*
ITEM 2
ITEM 3
ITEM 4
ITEM 5
31 (ENT) include SRS sentence in output (status of received signals)
40 (ENT) include RMA sentence in output
0 (ENT) end of sequence
Table 7—Northstar 800 Series Output Port Setup
* Only used if you want the waypoint to which you are navigating to be automati-
cally transferred to the 941X’s waypoint database.
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con n ect in g t o
ot h er d evices
Interfacing to other devices requires slightly different pin/ wire connec-
tions. For example, use the following table to enable the 941X to com-
municate with a Yeoman electronic chart plotter.
$ CONNECT TO EITHER %
YEOMAN
WIRES
941X PORT 1
941X PORT 2
NMEA OUT (white)
NMEA IN (brown #3)
white w/brown stripe (#6)
(DATA A+)
Data Return (green)
white w/blue stripe (#4)
NMEA OUT (violet#12)
blue w/white stripe (#8)
white (#5)
yellow (#15)
black (#10)
(GROUND)
NMEA IN (red)
(DATA +)
RETURN (black)
(GROUND)
Table 8—Yeoman Electronic Plotter Setup with 941X
If your 941X is not equipped with an internal beacon receiver, you can
interface it with an external Northstar model 8800, 8401 or 8400 bea-
con receiver, or other source of differential corrections. As described on
page 74, differential corrections greatly enhance the accuracy of GPS by
improving your position fixes to accuracy of 2-5 meters in most cases.
con n ect in g t o an
ext ern al s ou rce
of d ifferen t ial
correct ion s
To take advantage of this extra level of precision, connect the Northstar
beacon receiver to the 941X’s RS-232 port as follows:
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8800 DGPS Sensor
Pin 21 (receive)
Pin 20 (transmit)
Pin 17 (ground)
941X Interface Connector
red (RS-232 output) #18
green (RS-232 input) #16
tan (RS-232 ground) #17
8400 beacon receiver
black (receive)
941X Interface Connector
red (RS-232 output) #18
green (RS-232 input) #16
tan (RS-232 ground) #17
white (transmit)
orange (ground)
8401 beacon receiver
yellow (receive)
941X Interface Connector
red (RS-232 output) #18
green (RS-232 input) #16
tan (RS-232 ground) #17
blue (transmit)
orange (ground)
Table 9—Connecting to External NS Beacon Receiver
(For connection to other sources of differential corrections, refer to the
manufacturer’s instructions for wiring information.)
Now you’re ready to set up the 941X to receive the data from the external
source, using the RS-232 interface port. Press the STAR key until you
display the USER CUSTOMIZATION SCREEN. Press the PORT
SETUP OPTIONS menu key. The following screen will be displayed
(information displayed by your 941X in the RS-232 SETUP box at this
time may be different):
"
In order to receive SC-104 corrections through the 941X’s RS-232 inter-
face port, the port information box in the lower center of the screen must
read: SC-104 IN. If the port is presently set up for anything other than
SC-104 IN, press EDIT to change this setting. Use the up or down cursor
arrow keys to display SC-104 IN and press ENTER.
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Use this same EDIT procedure to set the baud rate to match that of the
external device, if necessary. (Refer to the external device’s instructions
for correct baud rate setting.) The 941X is now configured to accept dif-
ferential corrections from an outside source.
The RS-232 port is used for interfacing to an external DGPS beacon re-
ceiver, an external device that accepts SC-104 differential corrections, or
a personal computer.
RS-232 Port
When connected to a beacon receiver, you can receive differential cor-
rections through the RS-232 port. This is useful if your 941X is not
equipped with an internal beacon receiver, but you want to navigate us-
ing differential corrections.
If your 941X features an internal Northstar beacon receiver, you can use
the RS-232 port to transmit its differential corrections to another device
that accepts them.
If you wish to download your waypoints to a personal computer, or to
have the unit upgraded by your dealer or the factory with new operating
software, you can connect to a PC using the RS-232 port.
Following are descriptions of the RS-232 port’s various settings:
SC-104 OUT outputs differential corrections from your 941X’s internal
beacon receiver to an external device that accepts the standard SC-104
data stream. When using SC-104 OUT, be sure that the BAUD RATE
setting also matches the baud rate requirements of the receiving device.
SC-104 ou t
SC-104 in
SC-104 IN accepts differential corrections from any external source
transmitting the standard SC-104 data stream. Use this setting if your
941X is not equipped with an internal DGPS beacon receiver and you
wish to receive differential corrections from an external source. When
using SC-104 IN, be sure that the BAUD RATE setting also matches the
baud rate of the transmitting device.
NOTE
SC-1 0 4 IN
Switching to
enables the 941X to receive DGPS cor-
rections from an external source and disables the internal
DGPS beacon receiver (if installed).
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The COPY PORT function enables you to interface the 941X to many
Personal Computers without the need for an RS-422-to-RS-232 con-
verter. Many PC application programs for waypoint/ route loading, chart
programs, data logging, etc. can be used. The function “copies” the out-
put of the specified port 1 or port 2 data format (NMEA 0180, NMEA
0183, DATAMARINE CDX, or RAYTHEON 0183) to the RS-232
port’s output for direct connection to your computer.
cop y p ort 1
cop y p ort 2
1. At the PORT SETUP OPTIONS screen, confirm that the port you
wish to copy is presently set up to output the data format you wish
to use by pressing the PORT 1 SETUP or PORT 2 SETUP menu
key. If necessary, make changes now, using the EDIT menu key,
and press ENTER, then RETURN when you are done to return to
the PORT SETUP OPTIONS screen.
"
2. Change the RS-232 SETUP option (if necessary) to display the ap-
propriate COPY PORT 1 or COPY PORT 2 selection by pressing
the EDIT menu key and using the up/ down cursor arrow keys to
change the selection. Press ENTER when you are finished, or
CLEAR to leave the RS-232 port setup unchanged.
The 941X will now copy and output the specified port’s data format
through the RS-232 port to an external device.
The RS-232 port’s DIAGNOSTIC option is for future factory service di-
d iag n os t ic
p ort off
agnosis of 941X operating parameters.
Use this setting when the RS-232 port’s input or output functions are not
needed.
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APPENDIX
Norths tar 941X Sp ecifications
Position Data
Sys tem
Featu res
•
Latitude/ longitude (158 datums) from GPS with 1-second updates
•
Phantom Loran-C TDs (calculated from GPS) Loran-C TDs (from
your existing loran: 1 second from Northstar 800 series, 2 seconds
from other lorans)
•
Real-time receiver status screens
Steering Screens
•
•
•
•
Large, easy-to-read graphical presentation
Waypoint name, position
Bearing and distance to waypoint
Cross-track error (numeric and two graphic screens: traditional and
3-dimensional)
•
•
•
•
•
•
•
•
Heading correction
Speed Over Ground
Course Over Ground
Time-to-go
Estimated Time of arrival
Estimated Time Enroute
Speed of advance
Automatic magnetic variation
NavLog
•
•
•
•
•
•
•
Arrival time for waypoints passed
ETA for all waypoints not yet passed in trip
ETA for total trip
Reverse the trip
Add waypoints to end of trip
Distance and bearing for all legs
Skip forward and back in trip
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Waypoint & Route Management
•
•
•
•
•
•
•
•
•
•
•
Avoidance Waypoints
Enter wpts as lat/ lon, distance and bearing, or loran TDs
Displays 30 closest waypoints
Store 1,000 waypoints
Store up to 500 routes
Stores waypoints/ route
Update waypoint coordinates to ship's position
Edit/ erase waypoints or routes
Plan Route function
Plot any route with automatic chart scale selection
Time-To-Go
Waypoint Navigation
•
•
•
Navigate to coordinates, waypoints and along routes
Save current position
Steer to new point function (go to any waypoint or coordinates at
any time)
•
•
•
Waypoint queuing
Follow stored routes forward or backward
Plot current route with other local data
Plotter Functions
•
•
•
Plotter shows track history, nearby wpts, avoidance areas
Speed Over Ground
Course Over Ground
Miscellaneous Functions:
•
•
•
•
•
Anchor watch
Avoidance Area Alarm
GPS clock
TideTrack
Tide data by Marisystems, Inc
.
•
•
Type: LI Frequency, C/ A code (SPS), 12-channel, continuous track-
ing
GPS Receiver
Sensitivity: C/ N0 >34 dB-Hz
•
•
•
Navigation Accuracy:
3m 2DRMS with Differential
100m 2DRMS without Differential (S/ A on)
•
Navigation update rate: 1 per second
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•
•
•
•
Time To First Fix: 30 seconds (typical)
Dynamics: Velocity: 1800 km/ h
Acceleration: 4m/ sec; Jerk: 2m/ sec2
Operating Modes: 2D Nav, 3 or more satellites; 3D Nav, 4 or more
satellites visible
•
•
SC-104: Processes all USCG SC-104 message types, including 1 and 9
EMI: FCC Part 15 subpart J
•
•
•
•
•
Two bi-directional NMEA I/ 0 ports
One bi-directional RS-232 port
Waypoint upload/ download capability
Operating software upload
Interfaces
NMEA output sentences: APB, BOD, BWC, BWC (1.5), GGA, GLC,
GLL, GLL (1.5), GSA, GSV, HSC, RMA, RMB, RMC, RNN (1.5), VTG,
WCV, WPL, XTE, ZDA, ZTG (conforms to NMEA v. 2.1)
•
•
•
NMEA input sentences: WPL and others
Accepts external differential corrections
Accepts external loran receiver
•
•
•
Dimensions: 10.8" W x 6.5" H x 3.3" D
Slim “mount anywhere” waterproof unit
Ph ys ical
Featu res
320 x 240 pixel high-temperature, backlit, transflective graphics
LCD
•
•
•
•
•
•
•
•
Large (5.75") easy-to-read screen
High-contrast screen with anti-reflection coating to minimize glare
Audio beeper for alarms and confirmation of actions
Large, easy-to-use backlit controls
Easy removal for secure storage
Internal Beacon Receiver for differential corrections (optional)
Power: 10–40 VDC; 12 watts with internal Beacon Receiver
Operating temperature: Oº C–55º C max.; 95% relative humidity,
non-condensing
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Dim en s ion s
Figure 13—941X Dimensions
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Signal Processing
In tern al Beacon
Receiver
•
•
•
•
•
•
•
•
•
•
•
Number of Channels:
Frequency Range:
2
283.5–325.0 kHz
< 2 Hz
(op tional)
Tuning Resolution:
Minimum Signal Strength:
Dynamic Range
1µV/ m @ 100bps
> 100 dB
Adjacent Channel Rejection:
> 50 dB at 1 kHz
Acquisition Time:
5 seconds, manual command
15 seconds, automatic warm start
15 minutes, automatic cold start *
Predictive variable length
Noise Blanker:
Signal Detection:
Acquisition via FLL (frequency-locked loop);
tracking via PLL (phase-locked loop)
Data Processing
Demodulation:
Data Decoding:
MSK Bit Rates:
MSK (Minimum Shift Keying)
Parallel-matched digital filters
25, 50, 100, 200 (automatically selected)
Power Requirements
Power Consumption: 2 Watts
Data Ports
DGPS Correction Output Port:
RTCM SC-104 Version 2.0—6 of 8
RS-232-C
9600 or 4800 baud
Environmental
Whip Antenna:
ACU:
Height:
11 inches
Diameter:
Weight:
2.6 inches
1.5 pounds
Antenna:
48-inch fiberglass whip (not supplied)
(Shakespeare 4' #173 loaded, or Radio Shack
#21-934)
Rev. D
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•
•
•
•
•
•
•
•
•
•
•
•
Frequency:
Finish:
1575 MHz ±2 MHz
Outdoor Weatherable Polymer
Right-Hand Circular
22 Ounces
Com b o GPS /
DGPS An ten n a
Polarization:
Weight:
Axial Ration
Altitude:
3 dB Max.
12,000 Feet
Noise Figure:
Temperature:
Impedance:
VSWR:
2.5 dB Max.
-40º C to +70º C
50 Ohm
<2.0 : 1
Band Rejection
Power Handling:
35dB @ 1625 MHz
1 Watt
Immunity to electromagnetic environment (1988/’92 amend.):
IEC Com p lian ce
Evaluation
Standard
Radiated emissions IEC 945 (1995) per 17.3, 17.4
Low temperature
Dry heat
IEC945 (1995) per 4.5.4.2.4
IEC 945 (1995) per 4.5.2
IEC 945 (1995) per 4.5.3
IEC 945 (1995) per 4.5.10
IEC 945 (1995) per 4.5.7
IEC 529–IPX 5
Damp heat
Corrosion
Vibration
Rain test
Page 134
Appendix
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GLOSSARY
accuracy:
—the accuracy of displayed lat/ long coordi-
absolute accuracy
nates of your present position as compared to lat/ long determined
from a chart or other reference source.
—the ability to return to the same location
repeatable accuracy
using a receiver’s previously-obtained coordinates.
acquisition: The procedure during which a GPS receiver attempts to
track satellites before a position fix can be computed.
almanac: Data describing the precise orbits of GPS satellites, obtained
automatically from satellite signals and stored in a GPS receiver.
The receiver requires about 15 minutes to collect almanac data the
first time it is turned on. Thereafter, it can usually use the alma-
nac data collected previously.
chain: A group of loran transmitters comprised of a master station and
at least two secondaries.
coverage: The extent to which a geographical area is encompassed by
usable GPS or loran signals.
cursor: The display panel indicator that shows which character or char-
acter field is ready to be changed, acknowledged, or entered by
the user. It is activated and positioned by the user when required.
The 941X’s cursor will appear as an arrow or a flashing block, de-
pending on whether you are choosing or entering data.
ephemeris: Data used to calculate exact satellite positions, continually
updated and derived from information relayed to the 941X in each
satellite’s data stream.
Rev. D
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ETA: Estimated Time of Arrival at the next waypoint, as calculated by
the 941X according to your present speed of advance (SOA) and
distance to the waypoint.
ETE: Estimated Time Enroute to the next waypoint, as calculated by the
941X according to your present speed of advance (SOA) and dis-
tance to the waypoint.
GPS: Global Positioning System. A navigation system using signals from
earth-orbiting satellites. The system is capable of providing high
accuracy under all weather conditions.
great circle: Shortest possible path between two points on the surface of
a sphere.
GRI: Group Repetition Interval. The characteristic identifying period of
signals emitted by each loran transmitting chain. The identifier
9960 (Northeast US) indicates that the gap between the start of
any two adjacent master signals is 99,600 microseconds long.
interference: The electromagnetic interruption of a radio signal causing
poor signal reception. Interference may originate from external
sources (such as other radio transmitters) or from the vessel itself
(such as alternator noise or precipitation static).
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 deter-
mine position.
leg: The path between adjacent waypoints of a route.
longitude: Imaginary lines on the Earth's surface running North/ South
and expressed in degrees (0-180) east or west of the Prime Me-
ridian (a line running from the North to South Pole, passing
through Greenwich, England).
Loran-C: Acronym for LOng RAnge Navigation. System of land-based
radio transmitters emitting precisely-timed pulses which are re-
ceived and translated into position “fixes.”
magnetic variation: The difference between magnetic North and true
North. Since the difference varies according to geographic loca-
tion, the Northstar 941X automatically calculates magnetic varia
Page 136
Glossary
Rev. D
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tion and uses it to display bearings as magnetic north. The varia-
tion at any location changes slowly over a period of years, and the
941X compensates, according to the current calendar year.
master: The one loran transmitter in a “chain” of at least three stations
which initiates the series of coded pulses emulated by the secon-
daries.
precipitation static: Also known as “P-Static.” Precipitation-induced
electrical charge which can build up on antenna surfaces, result-
ing in poor radio reception.
readout: The panel of graphic images and alphanumeric characters used
by the 941X to display navigation data.
SNR: Signal to Noise Ratio. Guide number for determining the relative
quality of GPS, DGPS, or loran signals as compared to back-
ground radio “noise.”
TD: Time Difference. The measured amount of time—in millionths of a
second—between loran signals received from the master and the
secondary stations.
track: A desired line of travel.
waypoint: A particular location (defined for navigation purposes by its
lat/ lon, distance and bearing, or TDs), used as an intermediate or
final destination.
Rev. D
Glossary
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I N D E X
A
absolute accuracy......................................................... See accuracy, absolute
ACCURACY
repeatable........................................................................135
ACCURACY
absolute.......................................................................5, 135
absolute, GPS..............................................................6, 8, 9
absolute, loran .................................................................... 8
Coast Guard requirement.................................................... 6
DGPS ........................................ 2, 4, 7, 9, 26, 27, 34, 74, 75
from waypoints entered as TDs........................................... 9
GPS.................................................................2, 5, 9, 28, 75
GPS speed ....................................................................... 87
repeatable........................................................................... 6
repeatable, loran..........................................................7, 8, 9
updating waypoints ........................................................... 42
ACQUIRE indicator.......................................................................................... 2
ACU...................................................................... 101, 108, 109, 110, 112, 133
ALARMS
anchor drag..................................................................40, 70
arrive radius ...........................................................40, 71, 85
avoidance areas................................................................ 40
cross track ...................................................................40, 70
listing of types................................................................... 68
AN145 antenna............................................................................................ 106
AN150 antenna............................................................................................ 106
AN190 combo antenna................................................................................ 106
ANTENNA
DGPS ......................................................103, 108, 111, 112
GPS............................................. 9, 101, 103, 104, 106, 107
arrive radius....................................................................................... 40, 71, 84
asterisk.......................................................................................................... 49
avoidance areas ........................................... 4, 5, 10, 22, 23, 39, 40, 42, 43, 46
B
beacon receiver................................................ 9, 30, 83, 88, 101, 108–12, 124
BNC connector ............................................................................................ 107
brightness.................................................................................................. 5, 10
C
chart .............................................................................................23, 26, 42, 94
checksums .......................................................................................... 117, 122
CLEAR ALARM menu key............................................................................... 3
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COG.................................................................................................22, 23, 104
contrast ......................................................................................................... 14
COPY PORT function.................................................................................. 127
cross-track display limits................................................................................ 85
cursor (flashing)..........................................................................17, 30, 36, 135
D
data timeout............................................................................30, 68, 71, 76, 89
Datamarine.......................................................................................... 116, 127
datum ................................................................................................ 26, 85, 94
DGPS
antenna....................................................103, 108, 111, 112
checking status................................................................. 34
data timeout...............................................30, 68, 71, 76, 89
DIAGNOSTIC port function.......................................................................... 127
differential corrections...................................................................2, 6, 9, 26, 34
DISPLAY OPTIONS ...................................................................................... 78
distance and bearing ............................................38, 42, 47, 54, 56, 61, 65, 66
distance and speed units............................................................................... 79
drilling.......................................................................................................... 101
E
ephemeris.............................................................................................. 30, 100
exclamation point (flashing) ................................................2, 18, 39, 68, 69, 84
F
first start-up ................................................................................................. 2, 3
flashing cursor............................................................................17, 30, 36, 135
flashing exclamation point ..................................................2, 18, 39, 68, 69, 84
function keys ............................................................................................. 5, 16
G
GO TO menu key .......................................................................................... 55
GPS
absolute accuracy....................................................5, 6, 8, 9
accuracy ..........................................................2, 28, 75, 121
and DGPS.......................................... 6, 34, 82, 83, 108, 124
antenna........................................ 9, 101, 103, 104, 106, 107
Rev. D
Index
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checking status............................................................32, 34
comparing to Loran......................................................... 5, 7
converting coordinates from Loran TDs ............................ 42
converting coordinates to Loran TDs..............................9, 32
converting coordinates to Phantom Loran....................16, 82
displaying lat/lon ............................................................... 25
interfacing with Loran.........................................9, 10, 22, 30
receiver software revision.................................................. 92
satellite status..............................................................27, 34
selecting as navigation source ...............................32, 34, 82
with DGPS .......................................................................... 7
with Selective Availability .............................................6, 7, 8
GRI.................................................................................................... 31, 34, 54
grounding ............................................................................................ 100, 109
H
HDOP............................................................................................................ 28
I
I.D. message ................................................................................................. 81
INFORMATION windows............................................................................... 19
input ports............................................................... 11, 113, 114, 118, 125, 127
INTERFACING
compatibility.............................................112, 116, 120, 124
connector pin diagram......................................................113
general.......................................................................11, 112
port setup...................................................................90, 124
rear connectors layout......................................................103
to external beacon receiver........................................88, 124
to loran...............................................5, 9, 16, 22, 30, 31, 83
to Northstar 800 loran ................................................31, 123
wiring info...................................................................93, 113
K
keypad....................................................................................17, 18, 36, 74, 75
keypad test.................................................................................................... 93
L
latitude and longitude display adjust .............................................................. 80
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LORAN
absolute accuracy............................................................... 8
comparing to GPS............................................................... 5
converting TDs to lat/lon ................................................... 42
displaying TDs ...................................5, 9, 10, 16, 22, 30, 31
interfacing with GPS ....................................................30, 31
Phantom operation.......................................................32, 33
repeatable accuracy............................................................ 7
selecting as navigation source .......................................... 30
lowest sat elevation function.......................................................................... 90
M
magnetic variation ......................................................................................... 83
man overboard .......................................................................................... 5, 15
manual waypoint switching ............................................................................ 84
maximum saved waypoint number........................................................... 80, 81
MOB................................................................................... See man overboard
N
NAV LOG key.................................................................................... 17, 65, 66
NAVIGATION OPTIONS ............................................................................... 82
NMEA 0183....................................................................9, 31, 90, 112, 115–22
noise.............................................................................................103, 109, 112
Northstar 800....................................................................................31, 32, 123
O
output ports ................................................................11, 90, 93, 113, 115, 133
owner identification message......................................................................... 81
P
parts list....................................................................................................... 101
personal computer................................................................................... 37, 44
Phantom Loran...................................................................5, 16, 32, 33, 34, 82
plotter .......................................................................4, 8, 10, 16, 22, 24, 25, 47
PORT SETUP OPTIONS
wiring info screen.............................................................113
PORT SETUP OPTIONS
connecting to Northstar 800.............................................123
Rev. D
Index
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overview............................................................................ 90
programming the ports.............................................115, 125
RS-232 port .....................................................................126
POSITION key......................................................................................... 16, 22
P-static ........................................................................................................ 112
Q
QUESTION windows ....................................................................18, 19, 49, 81
QUICK PLOT........................................................................................... 47, 52
QUICK waypoint ............................................................................................ 54
R
RECEIVER OPTIONS ................................................................................... 87
recent alarms................................................................................................... 3
repeatable accuracy .................................................. See accuracy, repeatable
ROUTES
changing ................................................................46, 50, 51
creating........................................................................44–49
following............................................................................ 51
plotting...............................................................4, 22, 47, 52
saving as you travel ...............................................47, 48, 49
RS-232 ...........................................................................11, 115, 125, 126, 133
S
SA ..............................................................................See Selective Availability
SATELLITE
acquiring ............................................................................. 3
comprising GPS system...................................................6–8
LOWEST SAT ELEVATION option................................... 90
status.....................................................................27, 30, 34
SAVE/MOB.....................................................................................5, 15, 41, 42
SC-104 DGPS corrections..................................................2, 11, 125, 126, 133
Selective Availability.............................................................................. 6, 7, 27
serial number................................................................................................. 91
SERVICE INFORMATION............................................................................. 91
SKY SEARCH indicator................................................................................... 2
SNR..................................................................................................29, 32, 112
SOFTWARE VERSION
941X main board............................................................... 92
beacon receiver ................................................................ 92
GPS receiver .................................................................... 92
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SOG ........................................................................................................ 22, 23
STAR key .....................................................................5, 16, 30, 33, 68, 76, 82
STEER key.............................................................................................. 16, 55
steering distance precision ............................................................................ 86
STOP SAVE function..................................................................................... 49
T
TDs............................................................. 5, 9, 16, 31, 32, 33, 34, 38, 54, 123
tide ...........................................................................4, 5, 10, 16, 71, 72, 73, 74
TideTrack .......................................................................................... 10, 68, 71
TIME
changing time zone........................................................... 78
DGPS acquisition.............................................................133
DGPS data timeout........................................................... 76
DGPS data timeout................................................68, 71, 89
of arrival (ETA).............................................5, 57, 60, 64, 65
of day...........................................................5, 16, 25, 78, 80
of sunrise and sunset...................................................16, 78
of tide levels...................................................................... 72
speed averaging ............................................................... 87
to waypoint (ETE) ..............................................5, 57, 60, 64
TNC connector .................................................................................... 105, 106
track history....................................................................................5, 16, 22, 25
U
user customization screen............................................................................. 78
W
warning radius ......................................................................................... 39, 43
WAYPOINTS
arrive radius ...................................................................... 84
as avoidance areas......................................................23, 39
changing ..........................................................39, 42, 43, 54
converting GPS coordinates to TDs .................................... 9
creating............................................................16, 37, 44, 46
displaying...........................................................4, 17, 24, 50
displaying as TDs................................................................ 9
entering coordinates...............................................37–39, 54
entering name and description.......................................... 37
inserting in a route ...........................................44–46, 50, 51
lists ..............................................................................41, 46
plotting.........................................................5, 10, 16, 22, 39
Quick Start........................................................................ 54
Rev. D
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removing from a route....................................................... 51
saved as you travel......................................................42, 49
saving as part of a route...............................................44, 49
switching to next (auto) ..................................................... 84
switching to next (manually).............................................. 84
transferring to a personal computer................................... 44
updating coordinates....................................................42, 43
verifying entry.................................................................... 47
WAYPTS/ROUTES key................................................5, 16, 37, 43, 44, 54, 59
wiring (installation)....................................................................................... 102
wiring information screen............................................................................... 93
Z
zoom ............................................................................................10, 23, 47, 61
Page 144
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Rev. D
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