Lowrance LCX-20C User manual

Pub. 988-0151-261
www.lowrance.com
LCX-20C
Fish-finding Sonar & Mapping GPS
Operation Instructions

Copyright © 2004 Lowrance Electronics, Inc.
All rights reserved.
No part of this manual may be copied, reproduced, republished, transmitted or
distributed for any purpose, without prior written consent of Lowrance
Electronics. Any unauthorized commercial distribution of this manual is
strictly prohibited.
Lowranceis a registered trademark of Lowrance Electronics, Inc.
MapCreate, FreedomMaps, IMSand NauticPathsare
trademarks of LEI. Fishing Hot Spotsis a registered trademark of
Fishing Hot Spots Inc. Navionicsis a registered trademark of
Navionics, Inc.
eXitSource Database, copyright 2001-2004 Zenrin Co.
Ltd. Exit Authorityand eXitSourceare trademarks of
Zenrin Co. Ltd.
Lowrance Electronics may find it necessary to change or end our
policies, regulations and special offers at any time. We reserve the right
to do so without notice. All features and specifications subject to change
without notice. All screens in this manual are simulated. On the cover:
LCX-20C shown.
For free owner's manuals and other information,
visit our web site:
www.lowrance.com
Lowrance Electronics Inc.
12000 E. Skelly Dr.
Tulsa, OK USA 74128-2486
Printed in USA.

i
Table of Contents
Section 1: Read Me First!........................................................ 1
Capabilities and Specifications: LCX-20C .................................... 3
How Your Sonar Works ................................................................ 5
How Your GPS Works .................................................................. 6
Introduction to GPS and WAAS................................................... 7
How to use this manual: typographical conventions ................ 10
Section 2: Installation & Accessories.................................. 11
Preparations................................................................................ 11
Transducer Installation.............................................................. 11
Recommended Tools and supplies.......................................... 12
Shoot-thru-hull vs. Transom Mounting ................................. 14
Transom Transducer Assembly And Mounting..................... 15
TROLLING MOTOR BRACKET INSTALLATION .............. 21
TRANSDUCER ORIENTATION AND FISH ARCHES ....... 22
SHOOT-THRU-HULL PREPARATION ................................ 22
Speed/Temperature Sensors................................................. 27
GPS Antenna/Receiver Module .................................................. 28
Power Connections...................................................................... 31
Powering a NMEA 2000 Buss .................................................... 32
Powering Your Unit ................................................................ 32
NMEA 2000 Cable Connections ................................................. 34
Connecting to a NMEA 2000 Network................................... 34
NMEA 0183 Wiring (Data cable) ........................................... 35
Mounting the Unit: Bracket or In-Dash .................................... 36
MMC or SDC Memory Card Installation................................... 40
Other Accessories........................................................................ 41
Section 3: Basic Sonar Operation ....................................... 43
Keyboard ..................................................................................... 43
Power/lights on and off ............................................................... 44
Main Menu .................................................................................. 45
Pages ........................................................................................... 46
Satellite Status Page .............................................................. 46
Navigation Page ...................................................................... 47
Map Page................................................................................. 47
Sonar Page .............................................................................. 48
LCX-20C Sonar Quick Reference ............................................... 51
Sonar Operations ........................................................................ 52
Fish Symbols vs. Full Sonar Chart ........................................ 54
Other Free Training Aids ....................................................... 54
Section 4: Sonar Options & Other Features..................... 57
ASP(Advanced Signal Processing) ..................................... 57
Alarms ......................................................................................... 58

ii
Depth Alarms .......................................................................... 58
Zone Alarm .............................................................................. 59
Fish Alarm............................................................................... 60
Calibrate Speed........................................................................... 60
Chart Speed................................................................................. 61
ColorLine.................................................................................. 62
Depth Cursor............................................................................... 63
Depth Range - Automatic ........................................................... 64
Depth Range - Manual ............................................................... 65
Depth Range - Upper and Lower Limits ................................... 65
FasTrack.................................................................................. 66
Fish I.D.(Fish Symbols & Depths) ......................................... 67
FishTrack................................................................................. 69
Frequency (Change Transducer Frequency .............................. 69
HyperScroll.............................................................................. 70
Log Sonar Chart Data ................................................................ 70
Noise Rejection............................................................................ 71
Overlay Data ............................................................................... 71
Ping Speed & HyperScroll....................................................... 74
Reset Options .............................................................................. 75
Reset Water Distance ................................................................. 76
Set Keel Offset ............................................................................ 76
Sensitivity & Auto Sensitivity.................................................... 77
Automatic Sensitivity ............................................................. 78
Sonar Chart Mode....................................................................... 79
Sonar Page & Sonar Chart Display Options ............................. 79
Full Sonar Chart ..................................................................... 80
Split Zoom Sonar Chart.......................................................... 81
Split Frequency Sonar Chart ................................................. 81
Digital Data/Chart .................................................................. 82
Customize Page Displays ........................................................... 82
FlashGraf............................................................................. 83
Map With Sonar Split Screen................................................. 84
Sonar Simulator.......................................................................... 85
Stop Chart ................................................................................... 86
Surface Clarity ............................................................................ 87
Transparency .............................................................................. 88
Upper and Lower Limits ............................................................ 88
Zoom & Zoom Bar ....................................................................... 89
Zoom Pan..................................................................................... 89
Notes........................................................................................... 90
Section 5: Sonar Troubleshooting ....................................... 91
Section 6: Basic GPS Operations ......................................... 95

iii
Keyboard ..................................................................................... 95
Power/lights on and off ............................................................... 96
Main Menu .................................................................................. 96
Pages ........................................................................................... 98
Sonar Page .............................................................................. 98
Satellite Status Page .............................................................. 98
Navigation Page .................................................................... 100
Map Page............................................................................... 101
GPS Quick Reference................................................................ 107
Find Your Current Position...................................................... 108
Moving Around the Map: Zoom & Cursor Arrow Keys........... 108
Selecting Any Map Item With the Cursor ............................... 109
Searching................................................................................... 109
Set a Waypoint.......................................................................... 111
Navigate To a Waypoint ........................................................... 113
Set Man Overboard (MOB) Waypoint...................................... 114
Navigate Back to MOB Waypoint ............................................ 114
Navigate to Cursor Position on Map........................................ 115
Navigate to a Point of Interest................................................. 117
Creating and Saving a Trail..................................................... 117
Displaying a Saved Trail .......................................................... 119
Navigating Trails...................................................................... 119
Visual Trailing ...................................................................... 120
Navigate a Trail (forward).................................................... 120
Transfer Custom Maps and GPS Data Files ........................... 122
Custom Maps: ....................................................................... 122
GPS Data files:...................................................................... 123
Cancel Navigation..................................................................... 124
Section 7: Advanced GPS Operations............................... 125
Find Distance From Current Position ..................................... 125
Find Distance From Point to Point .......................................... 125
Icons........................................................................................... 125
Create Icon on Map............................................................... 126
Create Icon at Current Position ........................................... 126
Delete an Icon ....................................................................... 126
Navigate to an Icon............................................................... 127
Routes........................................................................................ 127
Create and Save a Route ...................................................... 128
PC-created Routes............................................................. 128
Routes Created in the Unit............................................... 128
Delete a Route ....................................................................... 130
Edit a Route .......................................................................... 130
Navigate a Route................................................................... 131

iv
Navigate a Route in Reverse ................................................ 132
Trails ......................................................................................... 132
Delete a Trail ........................................................................ 132
Edit a Trail Name ................................................................. 132
Edit a Trail Color .................................................................. 133
Edit a Trail Pattern .............................................................. 133
Utilities...................................................................................... 134
Alarm Clock........................................................................... 134
Sun/Moon Rise & Set Calculator.......................................... 134
Trip Calculator...................................................................... 134
Trip Down Timer................................................................... 134
Trip Up Timer ....................................................................... 134
Waypoints.................................................................................. 134
Delete a Waypoint................................................................. 134
Edit a Waypoint .................................................................... 134
Waypoint Name................................................................. 134
Waypoint Symbol .............................................................. 135
Waypoint Position ............................................................. 135
Selecting a Waypoint ............................................................ 135
Set a Waypoint by Average Position .................................... 135
Set a Waypoint by Projecting a Position.............................. 135
Section 8: System & GPS Setup Options .......................... 137
Alarms ....................................................................................... 137
Auto Satellite Search................................................................ 138
Check MMC Files and Storage Space...................................... 138
Communications Port Configuration ....................................... 139
Configure NMEA ...................................................................... 139
Coordinate System Selection.................................................... 140
Map Fix ..................................................................................... 141
Customize Page Displays ......................................................... 143
GPS Simulator .......................................................................... 144
Hide GPS Features ................................................................... 145
Initialize GPS............................................................................ 145
Map Auto Zoom......................................................................... 146
Map Data................................................................................... 146
Pop-up Map Info.................................................................... 146
Map Boundaries .................................................................... 147
Fill Water With White .......................................................... 147
Map Overlays (Range Rings; Lat/Long Grid) ...................... 147
Map Datum Selection ............................................................... 147
Map Detail Category Selection................................................. 148
Map Orientation ....................................................................... 149
NavionicsCharts..................................................................... 150

v
Port Information ................................................................... 151
Tidal Current Information ................................................... 152
Tide Information ................................................................... 154
Pop-up Help............................................................................... 156
Reset Options ............................................................................ 156
Screen Contrast and Brightness .............................................. 157
Once in the Screen menu:................................................. 157
Set Language ............................................................................ 158
Set Local Time .......................................................................... 158
Once in the Time Settings menu:..................................... 158
Show WAAS Alarm................................................................... 159
Software Version Information.................................................. 160
Sounds and Alarm Sound Styles.............................................. 160
Once in the Sounds menu ................................................. 160
Track Smoothing....................................................................... 161
Trail Options ............................................................................. 161
General Trail Options ....................................................... 161
Delete All Trails .................................................................... 162
Update Trail Option.............................................................. 162
Update Trail Criteria (Auto, Time, Distance) ................. 162
Trail Update Rate (Time, Distance)................................. 162
Specific Trail Options........................................................ 163
Delete Trail ........................................................................... 163
New Trail............................................................................... 163
Trail Visible/Invisible and Other Trail Options .................. 163
Units of Measure....................................................................... 164
Section 9: Searching ............................................................ 165
Find Addresses.......................................................................... 165
Find Any Item Selected by Map Cursor .................................. 168
Find Interstate Highway Exits ................................................ 168
Find Map Places or Points of Interest (POI) ........................... 171
Find Streets or Intersections.................................................... 172
Find a Street ......................................................................... 172
Find an Intersection ............................................................. 174
Find Waypoints......................................................................... 176
Section 10: Supplemental Material ................................... 179
Notes.............................................. Error! Bookmark not defined.

vi
WARNING!
A CAREFUL NAVIGATOR NEVER RELIES ON ONLY ONE METHOD
TO OBTAIN POSITION INFORMATION.
CAUTION
When showing navigation data to a position (waypoint), a GPS unit will show
the shortest, most direct path to the waypoint. It provides navigation data to the
waypoint regardless of obstructions. Therefore, the prudent navigator will not
only take advantage of all available navigation tools when traveling to a
waypoint, but will also visually check to make sure a clear, safe path to the
waypoint is always available.
WARNING!
When a GPS unit is used in a vehicle, the vehicle operator is solely
responsible for operating the vehicle in a safe manner. Vehicle
operators must maintain full surveillance of all pertinent driving,
boating or flying conditions at all times. An accident or collision
resulting in damage to property, personal injury or death could occur if
the operator of a GPS-equipped vehicle fails to pay full attention to
travel conditions and vehicle operation while the vehicle is in motion.

1
Section 1:
Read Me First!
How this manual can get you out on the road, fast!
Welcome to the exciting world of digital sonar and GPS! We know
you're anxious to begin navigating and finding fish, but we have a favor
to ask. Before you grab the unit and begin installing it, please give us a
moment or two to explain how our manual can help you get the best
performance from your combination fish finder and GPS receiver.
First, we want to thank you for buying a Lowrance sonar/GPS unit.
Whether you're a first time user or a professional fisherman, you'll
discover that your unit is easy to use, yet capable of handling
demanding navigation and sonar tasks. When you team your unit with
our custom mapping software MapCreate6, you have an incredible
combination. With a full VGA color display, recording capability and
remarkable resolution, you won't find another GPS/sonar unit with this
much power and this many features for this price!
Our goal for this book is to get you on the water. Like you, we'd rather
spend more time boating or fishing and less time reading the manual!
So, we designed our book so you don't have to read the whole thing from
front to back to find the information you want. At the start (or end) of
each segment, we'll tell you what content is coming up next. If it's a
concept you're already familiar with, we'll show you how and where to
skip ahead for the next important topic. We've also made it easy to look
up any tips you may need from time to time. Here's how:
The manual is organized into 10 sections. This first section is an
introduction to the LCX-20C sonar and GPS. It tells you the basics you
need to know so you’ll easily be able to make the unit, not only tell you
where you are, but also where to find fish.
Section 2 will help you install your unit, the transducer and the GPS
antenna module. We'll also show you how to install the MultiMedia
Card (MMC) and give you some information on available accessories.
Section 3 covers Basic Sonar Operation. It will show you how easy it is
to run your sonar, right out of the box. This section features a one-page
Sonar Quick Reference. (If you've already jumped ahead and
figured out how to install the unit yourself, and you just can't
wait any longer, turn to the Quick Reference on page 51 and
head for the water with your unit!)
After you've gained some experience with your sonar, you'll want to
check out Section 4, which discusses advanced Sonar Options and
Other Features.

2
When you come to a sonar menu command on the unit's screen, you can
look it up in the manual by skimming over the table of contents, flipping
through Section 3, or scanning through the sonar options in Section 4.
If you're having difficulty with your sonar, you can find an answer to
the most common problems in Section 5, Sonar Troubleshooting.
The manual switches from sonar to navigation in Section 6, which
introduces you to Basic GPS Operations. This section features a one-
page GPS Quick Reference on page 107.
Section 6 contains short, easy-to-scan GPS lessons that follow one
another in chronological order. They're all you'll need to know to find
your way on the water quickly.
After you've learned the basics (or if you already have some GPS
experience), you may want to try out some of the unit's many advanced
navigation features. That brings us to Section 7, Advanced GPS
Operations. This section contains the rest of the unit's GPS command
functions, organized in alphabetical order.
When you come to a GPS menu command on the screen, you can look it up
in the manual by skimming over the table of contents, flipping through
Section 6, or scanning through the command portion of Section 7.
This unit is ready to use right out of the box, but you can fine tune and
customize its operation with dozens of options. Since sonar is the unit's
key feature, we put the main sonar options in Section 4. Some options,
such as screen brightness settings, affect both sonar and GPS
operations. We describe how to use those common options along with
GPS options in Section 8, System Setup and GPS Setup Options.
Section 8 is organized in alphabetical order.
In Section 9, we go into more detail on one of the unit's most remarkable
GPS capabilities — Searching. We'll introduce a search example in the
Basic GPS Operation section, but there are so many map items you can
search for, we had to give this function its own section in the manual! For
example, did you know your unit can look up business phone numbers,
like a virtual Yellow Pages? We’ll show you how in Section 9.
Finally, in Section 10, we offer Supplemental Material, including a list
of the GPS datums, warranties and customer service information.
Now, if you're into the fine details, glance over the next segment on
specifications to see how much sonar and GPS power your unit contains.
It's important to us (and our power users), but, if you don't care how
many watts of power the unit has, or how many waypoints it can store,
skip ahead to important information on how sonar works, on page 5.
(Background on GPS begins on page 6.)

3
Capabilities and Specifications: LCX-20C
General
Display:............................ High-brightness LCD; programmable to
viewing preference.
LCX-20C: 6.0" (15.2 cm) diagonal.
Resolution:...................... LCX-20C: 320 pixel x 240 pixel resolution;
76,800 total pixels; 256-color, full VGA.
Backlighting:.................. Fluorescent cold cathode backlit screen with
multiple lighting levels; backlit keypad.
Input power:................... 10 to 15 volts DC.
Current drain: ............... Sonar only: 500 ma lights off; 600 ma lights
on. With GPS and lights on: 700 ma.
Case size:......................... 7.3" H x 9.6" W x 3.7" D (18.5 x 24.4 x 9.4
cm); sealed and waterproof; suitable for
saltwater use.
MMC slots: ...................... Two in waterproof compartment (SD card
compatible).
Back-up memory: .......... Built-in memory stores sonar records and
GPS data for decades. User settings are
stored when unit is turned off.
Languages:...................... 10 languages selectable by user.
Sonar
Frequency:...................... Depending on transducer, either 50/200 kHz
dual-frequency or 200 kHz single-frequency.
Transducers: .................... Skimmertransducer with built-in
temperature sensor available. Use either a
dual-frequency transducer with 35°/12°cone
angles or a single-frequency transducer with a
20°cone angle. Both transducers operate at
speeds up to 70 mph (61 kts).
Transmitter: ................... Dual-frequency: 8,000 watts peak-to-
peak/1 kW RMS.
Single-frequency: 3,000 watts peak-to-
peak/375 watts RMS.
Sonar sounding
Depth capability:........... Dual-frequency: 3,000 feet (915 meters).
Single-frequency: 1,000 feet (305 meters)
Depth display:............... Continuous display.

4
Graph recording: .......... Up to 1 GB on one MMC (or SD) card
Audible alarms: ............. Deep/shallow/fish/zone.
Automatic ranging:....... Yes, with instant screen updates.
Auto bottom track:........ Yes
Zoom bottom track: ...... Yes.
Split-screen zoom:......... Yes.
Surface water temp: ..... Yes, built into transducer.
Speed/distance log: ....... Yes, with optional speed sensor.
GPS
Receiver/antenna:......... External; LGC-2000.
Recording:........................ MMC & SD memory cards for recording GPS
trip details and displaying charts or custom
maps.
Background map:.......... Built-in custom, detailed Lowrance map.
Contains: enhanced detail of continental U.S.
and Hawaii.
Custom mapping: .......... MapCreate6 software optional; optional
plug and play LEI FreedomMapsoffer the
same high-detail without the computer work
of MapCreate. Other plug and play mapping
options include IMSFishing Hot Spots,
LEI NauticPathscharts and Navionics
charts.
Mapping memory: ......... Up to 1 GB on one MMC (or SD) card.
Position updates: .......... Every second.
Position points: ............. 1,000 waypoints; 1,000 event marker icons.
Audible alarms: ............. Arrival/off-course/anchor.
Symbols for
waypoints or icons:....... 42.
Routes:............................. 100; up to 100 waypoints per route.
Plot Trails: ...................... 10 savable; up to 9,999 points per trail.
Zoom range:.................... 37 ranges; 0.05 to 4,000 miles.
NOTE:
The above memory capacities refer only to the unit's on-board
memory. The amount of GPS or sonar data you can record and save
for recall later is only limited by the number of MMC cards you have.

5
NOTICE!
The storage and operation temperature range for your unit is from -
4 degrees to +167 degrees Fahrenheit (-20 degrees to +75 degrees
Celsius). Extended storage or operation in temperatures higher or
lower than specified will damage the liquid crystal display in your
unit. This type of damage is not covered by the warranty. For more
information, contact the factory's Customer Service Department.
Phone numbers are listed on the last page.
How Your Sonar Works
Sonar has been around since the 1940s, so if you already know how it
works, skip down to read about the relatively new technology of GPS.
But, if you've never owned a sonar fish finder, this segment will tell you
the underwater basics.
Sonar is an abbreviation for SOund NAvigation and Ranging, a
technology developed during World War II for tracking enemy
submarines. (Lowrance developed the world's first transistorized
sportfishing sonar in 1957.) A sonar consists of a transmitter,
transducer, receiver and display. Here’s a simple explanation of how it
finds the bottom and the fish.
The transmitter emits an electrical impulse, which the transducer
converts into a sound wave and sends into the water. (The sound
frequency can't be heard by humans or fish.) The sound wave strikes an
object (fish, structure, bottom) and bounces back to the transducer,
which converts the sound back into an electrical signal.
The receiver amplifies this return signal, or echo, and sends it to the
display, where an image of the object appears on the scrolling sonar
chart. The sonar's microprocessor calculates the time lapse between the
transmitted signal and echo return to determine the distance to the
object. The whole process repeats itself several times each second.
Your sonar unit can record a log of the sonar signals that scroll across
the screen and save them to the MMC memory card. (These recordings
are also called sonar charts or sonar graphs.) You can replay this sonar
log in the unit using the Sonar Simulator function, or play it back on a
personal computer using our free Sonar Viewer. The viewer is available
for download from the Lowrance web site, www.lowrance.com.
You can save several different sonar log files, erase 'em and record new
ones, over and over again. The size of your sonar recordings are only
limited by the free space available on your MMC.

6
How Your GPS Works
You'll navigate faster and easier if you understand how this unit scans
the sky to tell you where you are on the earth — and, where you're
going. (But if you already have a working understanding of GPS
receivers and the GPS navigation system, skip on ahead to Section 2,
Installation & Accessories on page 11. If you're new to GPS, read on, and
you can later impress your friends with your new-found knowledge.)
First, think of your unit as a small but powerful computer. (But don't
worry — we made the series easy to use, so you don't need to be a
computer expert to find your way!) The unit includes a keypad and a
screen with menus so you can tell it what to do. The screen also lets the
unit show your location on a moving map, as well as point the way to
your destination.
This gimbal-mounted unit uses an external antenna/receiver module,
which makes the whole system work something like your car radio. But
instead of your favorite dance tunes, this receiver tunes in to a couple of
dozen GPS satellites circling the earth. (It will also listen in to the
WAAS satellites in orbit, but more about that in the upcoming segment
introducing you to GPS and WAAS.)
Your unit listens to signals from as many satellites as it can "see" above
the horizon, eliminates the weakest signals, then computes its location
in relation to those satellites. Once it figures its latitude and longitude,
the unit plots that position on the moving map shown on the screen.
The whole process takes place several times a second!
The performance doesn't stop there. Stored in the permanent memory
of every unit is a basic background map of the entire world. We lock it
in here at the factory — you can't change or erase this map.
The background map is suitable for many navigation chores, but for
maximum accuracy and much more detail, you need our optional map-
making software, MapCreate6. Some unit features — such as
searching for businesses and addresses — won't work without a custom
MapCreate map. There is so much detail in our background map (and
even more in MapCreate) that we'll describe its contents and
differences in Section 6, Basic GPS Operations, on page 95.
Another portion of the unit's onboard memory is devoted to recording
GPS navigation information, which includes waypoints, event marker
icons, trails and routes. This lets you look back the way you came. Think
of this data storage like the hard drive memory in a computer or a tape
in a cassette tape recorder. You can save several different GPS data files,

7
erase 'em and record new ones, over and over again. Like any computer
file, these GPS Data Files (file format *.usr) can be shared between
other Lowrance GPS or sonar/GPS units and even personal computers.
Your unit has one more thing in common with a personal computer.
Just as computers have a floppy disk drive for storing and exchanging
files, this unit has a slot for an MMC (MultiMedia Card) or SDC
(Secure Digital card) flash memory card. These solid-state memory
devices are about the size of a postage stamp, but can hold data ranging
from 8 MB to 1 GB in size. (Compare that to a floppy disk's 1.44 MB
capacity!) The unit uses all that MMC space for two key GPS purposes.
(The MMC is also used to record sonar logs. See page 5.)
First, you can backup your onboard GPS Data Files by copying them to
the MMC. Since the MMC is removable (like a floppy disk or a cassette
tape), you can store these GPS Data Files on a personal computer
equipped with an MMC card reader. (Or store them on a pocketful of
MMCs, if you don't have a computer.) Our MapCreate mapping software
can save, edit or create its own GPS Data Files, which can be copied to
the MMC and then loaded from the MMC into the unit's memory.
(NOTE: No matter where they come from, GPS Data Files must be
loaded from the MMC into memory before the unit can use them.)
The other key GPS use for MMCs is storage of special high-detail,
custom maps, which you can produce on your computer with our
MapCreate software. These MapCreate custom maps contain much
greater detail than the basic background map. These Custom Map
Files (file format *.lcm) can also be shared between other Lowrance
GPS or sonar/GPS units and personal computers. (For example, the
exact same MMC, custom map files and GPS data files can be used
interchangeably between your gimbal-mounted LCX-20C and the hand-
held iFINDERGPS receiver.)
The unit automatically reads Custom Map Files directly from the MMC
or SDC. To use a custom map, all you need to do is slide an MMC
containing a map into the unit.
Introduction to GPS and WAAS
Well, now you know the basics of how the unit does its work. You might
be ready to jump ahead to Section 2, Installation & Accessories, on page
11, so you can mount your unit and plug in the power. Or you might
want to see how our text formatting makes the manual tutorials easy to
skim. If that's the case, move on to "How to Use This Manual" on page
10. But, if you want to understand the current state of satellite
navigation, look over this segment describing how GPS and its new
companion WAAS work together to get you where you're going.

8
The Global Positioning System (GPS) was launched July 17, 1995 by
the United States Department of Defense. It was designed as a 24-
hour-a-day, 365-days-a-year, all weather global navigation system for
the armed forces of the U.S. and its allies. Civilian use was also
available, but it was less accurate because the military scrambled the
signal somewhat, using a process called Selective Availability (SA.)
GPS proved so useful for civilian navigation that the federal
government discontinued SA on May 2, 2000, after the military
developed other methods to deny GPS service to enemy forces. Reliable
accuracy for civilian users jumped from 100 meters (330 feet) under SA
to the present level of 10 to 20 meters (about 30 to 60 feet.)
Twenty-four satellites orbit 10,900 nautical miles above the Earth,
passing overhead twice daily. A series of ground stations (with precisely
surveyed locations) controls the satellites and monitors their exact
locations in the sky. Each satellite broadcasts a low-power signal that
identifies the satellite and its position above the earth. Three of these
satellites are spares, unused until needed. The rest virtually guarantee
at least four satellites are in view nearly anywhere on Earth at all times.
A minimum of three satellites are required to determine a 2D fix.
The system requires signal reception from three satellites in order to
determine a position. This is called a 2D fix. It takes four satellites to
determine both position and elevation (your height above sea level —
also called altitude). This is called a 3D fix.
Remember, the unit must have a clear view of the satellites in order to
receive their signals. Unlike radio or television signals, GPS works at
very high frequencies. These signals can be easily blocked by trees,
buildings, an automobile roof, even your body.

9
Like most GPS receivers, this unit doesn’t have a compass or any other
navigation aid built inside. It relies solely on the signals from the
satellites to calculate a position. Speed, direction of travel, and distance
are all calculated from position information. Therefore, in order for the
unit to determine direction of travel, you must be moving and the
faster, the better. This is not to say that it won’t work at walking or
trolling speeds — it will. There will simply be more "wandering" of the
data shown on the display.
GPS is plenty accurate for route navigation, but the U.S. Federal
Aviation Administration has special needs for aircraft traffic control
that go beyond basic GPS. The FAA has a plan under way to boost GPS
performance even further with its Wide Area Augmentation System, or
WAAS. This GPS add-on will include a time control element that will
help airliners fly closer together while avoiding collisions. In addition to
carefully spacing airplanes along travel corridors, WAAS will
eventually make instrument landings and takeoffs more accurate as it
replaces existing aviation navigation systems.
Non-aviators can use WAAS signals to make their GPS navigation even
more accurate. Your unit receives both GPS and WAAS signals. WAAS,
however, has some limits you should know about.
First, the U.S. government has not completed construction of the WAAS
system, so it is not yet fully operational. The ground stations are in place,
but only a few of the needed WAAS satellites have been launched.
WAAS can boost the accuracy of land GPS navigation, but the system is
designed for aircraft. The satellites are in a fixed orbit around the
Equator, so they appear very low in the sky to someone on the ground
in North America. Aircraft and vessels on open water can get
consistently good WAAS reception, but terrain, foliage or even large
man-made structures frequently block the WAAS signal from ground
receivers.
You'll find that using your GPS receiver is both easy and amazingly
accurate. It’s easily the most accurate method of electronic navigation
available to the general public today. But remember this receiver is
only a tool. Always have another method of navigation available, such
as a map or chart and a compass.
Also remember this unit will always show navigation information in
the shortest line from your present position to a waypoint, regardless of
terrain! It only calculates position, it can’t know what’s between you
and your destination. It’s up to you to safely navigate around obstacles,
no matter how you’re using this product.

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How to use this manual: typographical conventions
Many instructions are listed as numbered steps. The keypad and arrow
"keystrokes" appear as boldface type, so you can easily skim the
instructions and pick out what menu command to use.
Arrow Keys
The arrow keys control the movement of dotted cross-hair lines on your
mapping screen called the cursor. The arrow keys also control a
horizontal line depth cursor on the sonar screen. The arrow keys also
help you move around the menus so you can execute different
commands. They are represented by symbols like these, which denote
the down arrow, up arrow, left arrow and right arrow: ↓↑←→.
Keyboard
The other keys perform a variety of functions. When the text refers to a
key to press, the key is shown in bold. For example, the "Enter/Icons"
key is shown as ENT and the "Menu" key is shown as MENU.
Menu Commands
A menu command or a menu option will appear in small capital letters, in
a bold sans serif type like this: ROUTE PLANNING. These indicate that you are
to select this command or option from a menu or take an action of some
kind with the menu item. Text that you may need to enter or file names
you need to select are show in italic type, such as trail name.
Instructions = Menu Sequences
Most functions you perform with this unit are described as a sequence
of key strokes and selecting menu commands. We've written them in a
condensed manner for quick and easy reading.
For example, instructions for navigating a trail would look like this:
1. From the Map Page, press MENU|MENU|↓to MY TRAILS|ENT.
2. Press ↓to Trail 1|ENT|→|↓to NAVIGATE|ENT.
3. You are asked to wait while it converts the trail into a route.
4. The wait message disappears and the unit begins showing
navigation information along the trail. Now, begin moving and
follow your unit's directions.
In clearer terms, step 1 (above) means: "Start on the Map Page. Press the
Menu key twice. Next, repeatedly press (or press and hold) the down
arrow key to scroll down the menu and select (highlight) the My Trails
menu command. Finally, press the Enter key."
Step 2: "Press the down arrow key repeatedly to scroll to the trail
named Trail 1, and press Enter. Next, press the right arrow key and
then the down arrow key to highlight the Navigate command, then
press Enter."

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Section 2:
Installation & Accessories
Preparations
You can install the sonar and GPS systems in some other order if you
prefer, but we recommend this installation sequence:
CAUTION:
You should read over this entire installation section before
drilling any holes in your vehicle or vessel!
1. Determine the approximate location for the sonar/GPS unit, so you
can plan how and where to route the cables for the antenna, transducer
and power. This will help you make sure you have enough cable length
for the desired configuration.
2. Determine the approximate location for the transducer and its cable
route.
3. Determine the approximate location for the GPS antenna module
and its cable route.
4. Determine the location of your battery or other power connection,
along with the power cable route.
5. Install the transducer and route the transducer cable to the
sonar/GPS unit.
6. Install the GPS antenna and route the antenna cable to the
sonar/GPS unit.
7. Install the power cable and route it to the sonar/GPS unit.
8. Mount the sonar/GPS unit.
Transducer Installation
These instructions will help you install your Skimmertransducer on a
transom, on a trolling motor or inside a hull. These instructions cover
both single- and dual-frequency Skimmer transducers. Please read all
instructions before proceeding with any installation.
The smaller single-frequency Skimmers typically use a one-piece,
stainless steel mounting bracket. The larger dual-frequency Skimmers
typically use a two-piece, plastic mounting bracket. The trolling motor
mount uses a one-piece plastic bracket with an adjustable strap.
These are all "kick-up" mounting brackets. They help prevent damage if
the transducer strikes an object while the boat is moving. If the
transducer does "kick-up," the bracket can easily be pushed back into
place without tools.

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Read these instructions carefully before attempting the installation.
Determine which of the mounting positions is right for your boat. Use
extreme care if mounting the transducer inside the hull, because once
the epoxy is applied and it is set into position, the transducer cannot be
removed. Remember, the transducer installation is the most
critical part of a sonar installation.
Recommended Tools and supplies
If you prefer the option of routing the cable through the transom, you
will need a 1" drill bit. A transom mount requires use of a high quality,
marine grade above- or below-waterline caulking compound.
NOTE
The following installation types also call for these recommended
tools and required supplies (supplies are not included):
Single-frequency transom installations
Tools include: two adjustable wrenches, drill, #29 (0.136") drill bit, flat-
head screwdriver. Supplies: high quality, marine grade above- or below-
waterline sealant/adhesive compound.
Dual-frequency transom installations
Tools: two adjustable wrenches, drill, #20 (0.161") drill bit, flat-head
screwdriver. Supplies: four, 1" long, #12 stainless steel slotted wood
screws, high quality, marine grade above- or below-waterline
sealant/adhesive compound.
Single-frequency trolling motor installations
Tools: two adjustable wrenches, flat-head screwdriver. Supplies: plastic
cable ties.
Shoot-through hull installations
Tools: these will vary depending on your hull's composition. Consult your
boat dealer or manufacturer. Other tools are a wooden craft stick or
similar tool for stirring and applying epoxy, and a paper plate or piece
of cardboard to mix the epoxy on. Supplies: rubbing alcohol, 100 grit
sandpaper, specially formulated epoxy adhesive available from LEI (see
ordering information on the inside back cover). A sandwich hull also
requires polyester resin.
Selecting a Transducer Location
1. The location must be in the water at all times, at all operating speeds.
2. The transducer must be placed in a location that has a smooth flow of
water at all times. If the transducer is not placed in a smooth flow of
water, interference caused by bubbles and turbulence will show on
the sonar's display in the form of random lines or dots whenever the
boat is moving.