Garmin GPS 128 User manual

®
GPS 126/128
Marine
Navigator
ZOOM
Owner’s Manual
&
Reference
GPS 126 shown
126/128 Manual (new) 6/15/98 9:50 AM Page 1

Software Version 2.0 or above
© 1997 GARMIN International, Inc
1200 E. 151st Street, Olathe, KS USA 66062
Tel: [phone] or 800-800-1020
Fax: [phone]
Web Site Address: www.garmin.com
GARMIN (Europe) Ltd.
Unit 5,
The Quadrangle, Abbey Park Industrial Estate,
Romsey, SO51 9AQ, U.K.
Tel: [phone]
Fax: [phone]
GARMIN (Asia) Corp.
4th Fl., No. 1., Lane 45,
Pao-Hsing Road,
Hsin Tein,
Taiwan R.O.C.
Phone: [phone]
Fax: [phone]
All rights reserved. No part of this manual may be reproduced or transmitted in any
form or by any means, electronic or manual, including photocopying and recording, for
any purpose without the express written permission of GARMIN.
Information in this document is subject to change without notice. GARMIN reserves
the right to change or improve its products and to make changes in the content without
obligation to notify any person or organization of such changes or improvements.
GARMIN, AutoLocate,TracBack, and are all trademarks of GARMIN International
and may not be used without the expressed permission of GARMIN.
January 1998 - Part #190-00151-00 Rev. A - Printed in Taiwan.
i
126/128 Manual (new) 6/15/98 9:50 AM Page 2

INTRODUCTION
Packing List
GPS 126/128
OWNER’S
MANUAL
Welcome to the easiest-to-use fixed-mount GPS on the water! The GPS
126 and GPS 128 represent GARMIN’s continuing commitment to provide
mariners with quality navigation information in a versatile, accurate, and
user-friendly design which will be useful for years to come. Due to the simi-
larity between the GPS 126 and GPS 128, we have addressed both units in
one manual. This manual is organized into four sections for your conve-
nience:
Introduction gives a quick overview of the manual and contains the
table of contents and glossary of navigation terms.
Getting Started introduces you to the basic features of the unit with a
quick-start orientation to the GPS 126/128. This section has been designed to
acquaint you with the unit and provide a basic working knowledge necessary
to use the unit in typical conditions.
Reference provides detailed explanations of advanced features and oper-
ations in a topical format. This allows you to concentrate on a specific topic
quickly, without reading through sections of text that you may not need.
The Appendix section contains step by step instructions on how to ini-
tialize the unit for first time use, installation instructions and items with mul-
tiple listings, such as: map datums, time offsets, and the index.
Packing List
Before getting started with your GPS receiver, check to see that your
GARMIN GPS 126/128 package contains the following items. If you are miss-
ing any parts, please contact your dealer immediately.
Standard Package:
• GPS 126/128 Unit • Mounting Bracket with knobs
• Power/Data Cable • Owner’s Manual
• Quick Reference Guide
* The GPS 128 also comes with an external antenna with 30’ cable.
See your GARMIN dealer for accessories, including our PC kit.
Thanks for choosing the GARMIN GPS 126/128. We hope it will meet all
of your navigation needs.
ii
126/128 Manual (new) 6/15/98 9:50 AM Page 3

Caution
INTRODUCTION
iii
The GPS system is operated by the government of the United States,
which is solely responsible for its accuracy and maintenance. The system is
subject to changes which could affect the accuracy and performance of all
GPS equipment. Although the GPS 126/128 is a precision electronic
NAVigation AID (NAVAID), any NAVAID can be misused or misinterpreted
and, therefore, become unsafe.
Use the GPS 126/128 at your own risk. To reduce the risk of unsafe
operation, carefully review and understand all aspects of this Operator’s
Manual and thoroughly practice operation using the simulator mode prior to
actual use. When in actual use, carefully compare indications from the GPS
126/128 to all available navigation sources including the information from
other NAVAIDs, visual sightings, maps, etc. For safety, always resolve any dis-
crepancies before continuing navigation.
NOTE: This device meets requirements for Part 15 of the FCC limits for
Class B digital devices for home or office use. It has been tested for compli-
ance with all necessary FCC standards. This equipment generates, uses, and
can radiate radio frequency energy and, if not installed and used in accor-
dance with the instructions, may cause harmful interference to radio commu-
nications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to
other equipment, which can be determined by turning the equipment off and
on, the user is encouraged to try and correct the interference by relocating the
equipment or connecting the equipment to a different circuit than the affected
equipment. Consult an authorized dealer or other qualified service technician
for additional help if these remedies do not correct the problem. Operation is
subject to the following conditions: (1) This device cannot cause harmful
interference, and (2) this device must accept any interference received,
including interference that may cause undesired operation. The GPS 126/128
does not contain any user-serviceable parts. Repairs should only be made by
an authorized service center. Unauthorized repairs or modifications could
void your warranty and your authority to operate this device under Part 15
regulations.
126/128 Manual (new) 6/15/98 9:50 AM Page 4

1
INTRODUCTION
Table of
Contents
SECTION ONE Introduction
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Navigation Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
SECTION TWO Getting Started
Keypad Usage & Data Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Primary Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Power On & Marking a Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Position Page and Map Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Going to a Waypoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Compass Page & Cancelling A GOTO . . . . . . . . . . . . . . . . . . . . . . . .12
Clearing the Map Display, Adjusting Contrast, & Power Off . . . . . . . .13
SECTION THREE Reference
Satellite Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Backlighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Position Page & User Selectable Fields . . . . . . . . . . . . . . . . . . . . . . . .16
Marking a Position & Position Averaging Function . . . . . . . . . . . .18, 19
Waypoint Pages & Managing Waypoints . . . . . . . . . . . . . . . . . . . . . . .19
TracBack Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Creating and Using Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Using the Compass & Highway Pages . . . . . . . . . . . . . . . . . . . . . . . .33
Map Page, Zooming, & Panning . . . . . . . . . . . . . . . . . . . . . . . . . .37, 38
Map Page & Track Log Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . .39, 40
Menu Page & Distance/Sun Calculation . . . . . . . . . . . . . . . . . . . . . . .43
System Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Navigation Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Interface Setup & DGPS Interface . . . . . . . . . . . . . . . . . . . . . . . . .44, 45
Navigation Simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Appendix A––Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Appendix B—Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Appendix C—Specifications & Wiring . . . . . . . . . . . . . . . . . . . . . . . .58
Appendix D—Messages and Time Offsets . . . . . . . . . . . . . . . . . . . . . .60
Appendix E––Map Datums . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
Appendix F––Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
126/128 Manual (new) 6/15/98 9:50 AM Page 1

Glossary
INTRODUCTION
2
The GPS 126/128 is a powerful navigation tool that can guide you any-
where in the world. To better understand its operation and capabilities, it may
be helpful to review the basic terms and concepts briefly explained below.
Other navigation and GPS definitions used in the manual are defined in the
appropriate reference sections of the manual.
Almanac Data
Satellite constellation information (including location and health of satel-
lites) that is transmitted to your receiver from every GPS satellite. Almanac data
must be acquired before GPS navigation can begin.
Bearing
The compass direction from your position to a destination.
Course Made Good (CMG)
The bearing from the “active from” position (your starting point) to your
present position.
Crosstrack Error (XTK)
The distance you are off a desired course in either direction.
Desired Track (DTK)
The compass course between the “from” and “to” waypoints.
Differential GPS (DGPS)
An extension of the GPS system that uses land-based radio beacons to
transmit position corrections to GPS receivers.
Estimated Time of Arrival (ETA)
The time of day of your arrival at a destination.
Estimated Time Enroute (ETE)
The time left to your destination at your present speed.
126/128 Manual (new) 6/15/98 9:50 AM Page 2

3
INTRODUCTION
Glossary
Grid
Coordinate system that projects the earth on a flat surface, using square
zones for position measurements. UTM/UPS and Maidenhead formats are grid
systems.
Ground Speed
The velocity you are traveling relative to a ground position.
Latitude
The north/south measurement of position perpendicular to the earth’s
polar axis.
Longitude
An east/west measurement of position in relation to the Prime Meridian,
an imaginary circle that passes through the north and south poles.
Navigation
The process of traveling from one place to another and knowing where
you are in relation to your desired course.
Position
An exact, unique location based on a geographic coordinate system.
Track (TRK)
The direction of movement relative to a ground position.
Universal Transverse Mercator (UTM)
A grid coordinate system that projects global sections onto a flat surface to
measure position in specific zones.
Velocity Made Good (VMG)
The speed you are traveling in the direction of the destination.
Waypoint
A specific location saved in the receiver’s memory.
126/128 Manual (new) 6/15/98 9:50 AM Page 3

Navigation
Basics
INTRODUCTION
4
NORTH
“ACTIVE FROM”
WAYPOINT
NORTH
DTK
CROSSTRACK ERROR
BRG
TRK
GROUND SPEED
DISTANCE
“ACTIVE TO”
WAYPOINT
“ACTIVE LEG”
The GPS 126/128 provides steering guidance and navi-
gation information using degrees, a measurement measured
in a clockwise direction from a north reference. North is
described as 000º, east as 090º, south as 180º, and west as
270º. The diagram and compass rose below provide a graphic
illustration of the navigation terms used by the GPS 126/128.
More information on basic navigation and GPS are available
at your local library or bookstore.
126/128 Manual (new) 6/15/98 9:50 AM Page 4

5
INTRODUCTION
Keypad Usage
and Data Entry
P
Turns the unit on and off and
activates screen backlighting.
J
Scrolls through the main data
pages in sequence and returns
display from a submenu page
to the main page.
M
Captures a position and dis-
plays the mark position page.
G
Displays the GOTO page with
the waypoint highlighted for
GOTO operation.
F
Confirms data entry and
activates highlighted fields
to allow data entry.
Q
Returns the display to a previ-
ous page, or restores a data
field’s previous value.
B
Marks your present GPS posi-
tion and instantly sets a return
course while providing steer-
ing guidance.
I
Decreases the scale of the
moving map.
H
Increases the scale of the
moving map.
UD
Selects alphanumerical
characters and menu choices
and moves the field highlight
from field to field.
LR
Moves the selected character
field and moves the field
highlight from field to field.
DATA ENTRY
The arrow keypad is
used for all data entry.
Use the Uand D
keys to select letters,
numbers, and menu
options; use the Land
Rkeys to move the cur-
sor forward or back-
ward along the line.
Press Fto confirm
your entry.
126/128 Manual (new) 6/15/98 9:50 AM Page 5

Primary Pages
Before we start the tour, let’s briefly look at the five
primary information pages used for the GPS 126/128.
To switch between pages press either the
Q
or
J
keys (see below).
Satellite Page
The Satellite Page shows satellite positions and
signal strength. Satellite positions are displayed using
two circles and a center point. The outer circle shows
satellites on level with the horizon; the inner circle is
45º above the horizon; and the center point represents
satellites directly overhead. Knowing satellite positions
will show you the direction of any blocked signals.
The bottom of the page contains a row of signal
strength bars corresponding to each satellite being used.
Position Page
The Position Page shows you where you are, what
direction you’re heading, and how fast you’re going.
The top of the page contains a compass tape which
is a graphic representation of your heading.
The graphic compass tape reflects your head-
ing only while you are moving.
Your track and speed are indicated immediately
below. Underneath are two user-selectable fields for a
variety of data. The current position is displayed in lati-
tude and longitude or a user selectable grid format. A
12/24 hour clock is also provided.
Primary Pages
INTRODUCTION
6
Satellite Page
The Satellite Page will
allow you to monitor
satellite signal reception
and strength.
J
Q
!
#
Position Page
126/128 Manual (new) 6/15/98 9:50 AM Page 6

Map Page
The Map Page acts as a window. It allows you to
view your position, the “path” you have traveled over,
and nearby waypoints.
A diamond icon in the center of the screen repre-
sents your current position. As you move, you will see a
thin line called a track log appear along the path you
have just covered. Names of stored waypoints and
waypoint symbols can also be shown on the map.
The bottom corners of the screen always display
your current track and speed. When going to a way-
point, highlighting an on-screen waypoint, or using the
panning target crosshair, the corresponding distance
and bearing are shown at the top corners of the screen.
Navigation Page
A navigation page gives you steering guidance when
going to a waypoint. The GPS 126/128 has two naviga-
tion page choices: the Highway Page and the Compass
Page. The Highway Page is the default and will be
briefly explained here. The Compass Page is covered on
page 36.
The Highway Page uses a graphic highway to show
your movement in relation to your desired course. The
upper section shows bearing and distance to the way-
point and your current track and speed. The middle
portion contains the actual highway. The highway indi-
cates the crosstrack error, or distance and direction,
your are off-course from your waypoint. Always turn in
the direction the highway is pointing. For example, if
the highway points straight up, no turn is needed. If the
highway points right, you need to turn right until the
highway points straight up. The pointer just below the
CDI scale always points to your selected waypoint, rela-
tive to the direction you are moving. The remainder of
the page contains two user-selectable fields.
Menu Page
The last primary page is the Menu Page. The Menu
Page gives you access to the GPS 126/128’s waypoint
management, route, and setup features through a list of
submenus. The Menu Page is covered on page 43.
7
Map Page
The Map Page shows your
progress on a moving track
plotter and gives you a
bird’s-eye-view of sur-
rounding waypoints.
INTRODUCTION
Primary Pages
Highway Page
With the Highway Page,
you will get graphic steer-
ing guidance when navigat-
ing a route or going to a
single waypoint.
126/128 Manual (new) 6/15/98 9:50 AM Page 7

Getting Started Tour
Now that you are familiar with the primary pages,
it’s time to take a tour. This is a live tour and is to be
conducted with your unit installed and with the boat in
the water. The tour will take you through the receiver’s
basic features and functions as you move about on the
water and assumes that the GPS 126/128 is turned on
and initialized, (see page 52 for initialization proce-
dure) and that you have not changed any of the factory
settings (units of measure, selectable fields, etc.). If
these settings have been changed, the pictures and
descriptions in this manual may not match what you
see on your screen.
Navigation Simulator
If you are not able to take the Getting Started Tour
with your boat in the water, you may use the built-in
navigation simulator to practice using the GPS
126/128. To use the simulator, see page 51.
Marking a Position
To begin the tour, let’s take the position you have
acquired (either by just initializing the unit or by hav-
ing turned the unit on) and mark it as a waypoint for
future reference.
1. Press the
M
key to capture and hold your position.
To mark a position, you must have obtained a
2D or 3D fix, or have the receiver in simulator
mode. If you try to mark a position without a
position fix, you will be alerted with a ‘No GPS
Position’ message.
The mark position page will appear, showing the
captured position and a default 3-digit waypoint name.
Let’s change the default name to something a little more
meaningful, like ‘DOCK’.
2. Press the down arrow once to move the field highlight
from the ‘SAVE?’ field to the name field.
Power On &
Marking a
Position
GETTING
STARTED
8
The Welcome Page will
be shown while the unit
conducts a self test.
Press the UP arrow to
move forward through the
alphabet or numbers and
the DOWN arrow to
move backward.
!
#
126/128 Manual (new) 6/15/98 9:50 AM Page 8

3. Press
F
to clear the default waypoint name.
4. Press and hold the
U key to scroll through the
alphabet until the letter ‘D’ appears.
5. Press the
R key once to move the character highlight
to the next character space.
6. Repeat steps 3 and 4 until the word ‘DOCK’ is dis-
played.
7. Press
F
to complete entry of the name.
Each waypoint may also be assigned a custom way-
point symbol for easy waypoint recognition on the map
page.
1. Press
F
to activate the symbol menu.
2. Select the anchor symbol and press
F
.
3. Press the
D
key to highlight the ‘DONE?” field.
4. Press
F
to confirm the selected symbol.
5. With the ‘SAVE?’ field highlighted, press
F
to con-
firm that you want to save the position as a waypoint
named ‘DOCK’.
The mark position page will now be replaced by
the Position Page (or whatever page was displayed
prior to pressing the
M
key). The ‘DOCK’ waypoint
is now stored in the GPS 126/128’s memory, and will
remain there until you manually remove it or clear the
receiver’s memory. For more on waypoint management,
see pages 19-24.
Using the Position and Map Pages
Now that you’ve marked a position, let’s see how
the Position and Map Pages can be used to monitor
your progress as you head out into the open water.
As always, ensure your primary focus is on
boating traffic and monitor the GPS126/128
briefly when operating your boat.
9
The arrow keypad is used
for all data entry. Use the
UP and DOWN keys to
select letters, numbers, or
menu options, and use the
LEFT and RIGHT keys to
move the cursor forward or
backward along the line.
GETTING
STARTED
Position and
Map Pages
Position Page
!
#
126/128 Manual (new) 6/15/98 9:50 AM Page 9

Using the Position and Map Pages (cont.)
As you head out, the Position Page will help you
monitor your movement.
The direction you are moving (your track) and your
speed are displayed on the upper part of the page, just
below the graphic compass tape. The latitude and longi-
tude, along with two user-selectable displays, are con-
tinuously displayed in the middle of the page, and the
time of day is displayed below.
Now let’s change the display to the Map Page and
watch the track log of our tour:
1. Press the
J
key to change from the Position Page
to the Map Page.
To view a larger area on the Map Page, let’s change
the zoom scale from .2 (default) to 1.0 nautical mile.
To select a larger zoom scale on the Map Page:
1. Press the
H
key until ‘1.0 n.m. zoom scale’ appears.
Your current position is shown as the diamond in
the middle of the screen. The dark circle below the dia-
mond represents the position you created, with the line
between the two showing your track.
1. Once you have reached an area that allows for gener-
al changes in direction without interfering in the pas-
sage of other boats, mark your current position again
and name this waypoint “CHANNL”. (See ‘Marking a
Position’ on page 18.)
2. Next, make a moderate turn in any direction thats safe
for navigation and proceed for another 3 minutes.
Position and
Map Pages
GETTING
STARTED
10
The Map Page displays
your present position as a
diamond icon and provides
a real-time graphic “bread-
crumb” display of your
track right on the screen.
The moving map’s default
screen orientation is track-
up. “Track up” means that
your current direction of
travel is always up (or
towards the top of) the
screen. It can also be set for
north up, or desired track-
up orientation through the
map setup page.
User-
Selectable
Field
Current Speed
Track Over
Ground
Graphic
Compass Tape
User-
Selectable
Field
Position
Display 12/24 Hour
Time
126/128 Manual (new) 6/15/98 9:50 AM Page 10

Going To a Waypoint
Once you’ve stored the “CHANNL” waypoint in
memory, you can use the GPS 126/128 to guide you to
it by performing a simple GOTO. A GOTO is nothing
more than a straight-line course from your present posi-
tion to the destination you’ve selected.
Use caution when navigating. A “straight-line”
course reflects the shortest distance to a waypoint,
and does not navigate around obstructions, such
as land or buoys, etc.
Now that you have moved away from ‘CHANNL’ for
three minutes, let’s try navigating back to it.
To select a GOTO destination:
1. Press the
G
key.
2. The GOTO waypoint page will appear, displaying all the
waypoints in memory in alphabetical order.
3. Use
U or D to highlight the ‘CHANNL’ waypoint.
4. Press the
F
key to confirm that you want to navi-
gate to the displayed waypoint.
5. Press the
J
key to view the Graphic Highway Page.
11
The GOTO waypoint page
allows you to select your
destination from a list of all
available waypoints in the
GPS 126/128’s memory.
GETTING
STARTED
Going To a
Waypoint
Once a GOTO is activated,
the GPS 126/128 will
provid steering guidance
until the GOTO is can-
celled. To cancel a GOTO,
highlight the cancel prompt
at the bottom of the page
and press ENTER.
!
#
Bearing to
Waypoint
Destination
Waypoint
“Finish Line” CDI Scale
Distance to
Waypoint
Destination Waypoint
User-
Selectable
Fields
Track Over
Ground
Speed Over
Ground
Your Relative
Position
Directional
Pointer
126/128 Manual (new) 6/15/98 9:50 AM Page 11

Going To a Waypoint (continued)
The GPS 126/128’s Highway Page provides graphic
steering guidance to a destination, with an emphasis on
a straight-line course to the desired waypoint and the
distance and direction you are off course. The bearing
and distance to a waypoint–along with your current
track and speed, are displayed at the top of the screen,
with two user-selectable fields shown at the bottom.
As you head toward your destination, the middle
section of the screen provides visual guidance to your
waypoint on a moving graphic “highway”. The pointer
just below the CDI scale always points to your selected
waypoint relative to the direction you are moving.
Your present position is represented by the diamond
in the center of the course deviation scale. The line
down the middle of the highway represents your
desired track. As you navigate toward a waypoint, the
highway will actually move, indicating the direction
you’re off course, relative to the position diamond on
the CDI scale. To stay on course, simply steer toward
the center of the highway.
While navigating, you may decide to use the
Compass Page (see picture above left) instead of the
Highway Page.
To select the Compass Page:
1. While viewing the Highway Page, press
F
twice.
The Compass Page will now become the displayed
navigation page. This page provides a directional point-
er to your destination by using a rotating compass dis-
play to show direction of travel. It provides better steer-
ing guidance at slower speeds for travel with many
directional changes.
To switch back to the Highway Page, press ENTER
twice.
Cancelling a GOTO
If you decide to stop navigating to the active way-
point, all you have to do is cancel the GOTO.
To cancel an active GOTO:
1. Press the
G
key.
GOTO Waypoint
& Cancelling
GOTO
REFERENCE
12
The 126/128 will also pro-
vide steering guidance with
a graphic Compass Page.
To change the display from
the Highway Page, press
ENTER twice.
Once you reach the selected
distance from the destina-
tion (based on your present
speed and course), an
arrival message will appear
on the message page.
126/128 Manual (new) 6/15/98 9:50 AM Page 12

2. Use the arrow keypad to move the field highlight to
the ‘CANCEL GOTO?’ prompt at the bottom of the page
and press
F
.
Clearing a Cluttered Map Display
After you’ve used the GPS 126/128 for a few trips,
you may find that your map display has become a bit
messy from keeping track of your every move. For
practice, let’s clean up the screen by clearing the track
log (the plot points left on the Map Page) we’ve just
created during the Getting Started Tour.
1. Press
J
or
Q
until the Map Page appears and
press
F
.
2. Use the
D key to move the field highlight to the
‘TRACK SETUP’ option.
3. Press
F
to access the track setup page.
4. Highlight the ‘CLEAR LOG?’ option. The clear log con-
firmation page will appear.
5. Use the
L key to highlight the ‘Yes’ prompt.
6. Press
F
to finish.
Adjusting the Contrast
You can adjust the screen contrast from the Satellite
Page and also from the Menu Page (see page 47)
To adjust the contrast from the Satellite Page:
1. Press the J or Q key until the Satellite Page
appears.
2. Press the arrow keypad left or right until the desired
level is reached, and press
F
.
Turning the Receiver Off
You’ve now gone through the basic operation of
your new GPS receiver. We encourage you to experi-
ment with the GPS 126/128. If you encounter any
problems using the unit or want to take advantage of
the GPS 126/128’s more advanced features, refer to the
reference section of this manual.
To turn the GPS 126/128 off:
1. Press and hold the
P
key for 3 seconds.
13
Highlight the ‘CLEAR
LOG?’ prompt and press
ENTER to clear the track
log. Once all 1024 points
are used, the oldest point
will be continuously deleted
to make room for the latest
track log point.
REFERENCE
Clearing the
Map, Adjusting
Contrast, &
Power Off
Instantly change the screen
contrast by pressing the
arrow keypad while viewing
the Satellite Page.
126/128 Manual (new) 6/15/98 9:51 AM Page 13

Satellite Page
The GPS 126/128’s Satellite Page displays the status
of various receiver functions. The status information
will help you understand what the GPS 126/128 is
doing at any given time, and will tell you whether or
not the receiver has calculated a position fix.
Sky View and Signal Strength Bars
The sky view and signal strength bars give you an
indication of what satellites are visible to the receiver,
whether or not they are being used to calculate a posi-
tion fix, and the signal quality. The satellite sky view
shows a bird’s-eye view of the position of each available
satellite relative to the unit’s last known position. The
outer circle represents the horizon (north or track up);
the inner circle 45º above the horizon; and the center
point directly overhead. You can use the sky view to
help determine if any satellites are being blocked, and
whether you have a current position fix (indicated by a
‘2D NAV’ or ‘3D NAV’ in the status field). You can also
set the sky view to a track-up configuration by changing
the “orientation” option on the Map Page. (See pg. 41
for Map Setup instructions.)
When the receiver is looking for a particular satel-
lite, the corresponding signal strength bar will be blank
and the sky view indicator will be highlighted. Once the
receiver has found the satellite, a hollow signal strength
bar will appear, indicating that the satellite has been
found and the receiver is collecting data from it. The
satellite number in the sky view will no longer appear
highlighted. As soon as the GPS 126/128 has collected
the necessary data to calculate a fix, the status field will
indicate a 2D or 3D status.
Satellite Page
REFERENCE
14
The GPS 126/128’s
Satellite Page will help
you determine which
satellites are in view, and
whether or not any satel-
lites are being “shaded”
or blocked. (See satellites
07 and 19 above).
By periodically monitor-
ing the signal strength
bars at the bottom of the
page and the north up
sky view, you will be able
to see how moving to
another area with a
clearer view of the sky
will improve satellite
reception and speed up
signal acquisition.
Horizontal
Accuracy
Signal Strength
Indicators
Skyview
Display
Status
Field
126/128 Manual (new) 6/15/98 9:51 AM Page 14

Receiver Status and EPE
Receiver status is indicated at the top left of the
page, with the current horizontal accuracy (EPE, esti-
mated position error, in feet or meters) at the top right.
The status will be shown as one of the following condi-
tions:
Searching— the GPS 126/128 is looking for any
available satellites in view.
AutoLocate— the GPS 126/128 is initializing and
collecting new almanac data. This process can take
5 minutes, depending on the satellites currently in
view.
Acquiring— the receiver is collecting data from
available satellites, but has not collected enough
data to calculate a 2D fix.
2D Navigation— at least three satellites with
good geometry have been locked onto and a 2-
dimensional position fix (latitude and longitude) is
being calculated. ‘2D Diff’ will appear when you are
receiving DGPS corrections in 2D mode.
3D Navigation— at least four satellites with good
geometry have been locked onto, and your position
is now being calculated in latitude, longitude and
altitude. ‘3D Diff’ will appear when you are receiving
DGPS corrections in 3D mode.
Poor GPS Coverage— the receiver isn’t tracking
enough satellites for a 2D or 3D fix.
Not Usable— the receiver is unusable, possibly
due to abnormal satellite conditions. Turn the unit
off and back on to reset, and reinitialize the receiv-
er if necessary.
Simulator— the receiver is in simulator mode.
Screen Backlighting
The GPS 126/128 feature illuminates the screen
display for a user-defined interval (the default is 15 sec-
onds). There are three stages of backlighting. When
backlighting is on, a bulb icon will appear at the bot-
tom left of the sky view. To adjust the duration of
screen backlighting, refer to the system setup section
(see page 47).
Note: A bulb icon will appear on the Satellite Page
when backlighting is on.
15
The signal strength bars at
the bottom of the page will
not appear until the GPS
126/128 has found the
satellites indicated at the
bottom of the screen.
REFERENCE
Receiver Status
& Screen
Backlighting
When backlighting is on, a
bulb icon will appear on
the Satellite Page.
Use the icon to determine
if backlighting is turned
on during daylight hours.
126/128 Manual (new) 6/15/98 9:51 AM Page 15

EZinit Option Prompt
The Satellite Page also provides access to the EZ init
prompt whenever a position fix has not been calculated.
(The unit must be in searching, AutoLocate, acquiring,
simulator, or poor coverage mode.) This allows you to
reinitialize the unit (see Appendix A), and is useful if
you have traveled over 500 miles with the receiver off
and must initialize your new position. (The EZ
init
prompt will automatically appear if the receiver needs
to be initialized. The prompt may also appear during
normal use if the antenna is blocked from receiving
satellite signals.
Note: The GPS 126/128 features an internal lithium
battery that will maintain the unit’s memory when the
receiver is not running.
Memory Erase Function
You may erase the GPS 126/128’s memory in four
quick steps. This will cause all stored data to be deleted,
including routes, waypoints, and the track log.
To erase all stored data:
1. Ensure that the GPS 126/128 is turned off.
2. While holding down the
M
key, press the
P
key
to turn the unit on. After the unit turns on, release the
keys. A warning message will appear with “Yes?”
highlighted, and ask you to confirm your selection.
3. If you do not wish to erase all stored data, press
R
and
F
to cancel the emergency erase.
4. If you do wish to complete the emergency erase, press
F
to confirm.
Position Page
The second page in the GPS 126/128’s main page
sequence is the Position Page. This page shows you
where you are, what direction you’re heading, and how
fast you’re going. The Position Page is most useful when
you are traveling without an active destination way-
point. The graphic compass tape across the top of the
page indicates the direction you’re heading (only while
you’re moving).
EZinit Prompt
and Memory
Erase
REFERENCE
16
Upon activating the
Memory Erase Function,
you will be asked to con-
firm your decision.
If you travel more than
500 miles with the receiv-
er off, reinitialize the unit
to your new position by
using the EZinit feature.
To access EZinit, press
ENTER from the Satellite
Page before any satellites
are acquired.
126/128 Manual (new) 6/15/98 9:51 AM Page 16