JRC LMS-520C Manual (252 Sider)

Pub. 988-0151-461

www.lowrance.com

LMS-520C & LMS-525C DF

Fish-finding Sonar & Mapping GPS

Installation and Operation

Instructions

No part of this manual may be copied, reproduced, republished, trans-

mitted or distributed for any purpose, without prior written consent of

Lowrance. Any unauthorized commercial distribution of this

manual is strictly prohibited.

Lowrance® is a registered trademark of Lowrance Electronics, Inc.

MapCreate™, FreedomMaps™ and NauticPath™ are trademarks of

LEI. Fishing Hot Spots® is a registered trademark of Fishing Hot Spots

Inc. LakeMaster® and Pro Maps are trademarks or registered trade-

marks of WayPoint Technologies, Inc. Navionics® is a registered

trademark of Navionics, Inc. DURACELL® is a registered trademark of

Duracell, Inc. RAYOVAC® is a registered trademark of Rayovac Corpo-

ration. Energizer® and e2® are registered trademarks of Energizer Hold-

ings, Inc.

Points of Interest Data in this unit are by infoUSA,

trademark of infoUSA, Inc.

Lowrance Electronics may find it necessary to change or end our poli-

cies, 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:

LMS-525CDF.

For free owner's manuals and the most current information on

this product, its operation and accessories,

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

Specifications: LMS-520c and LMS-525cDF.......................... 3

How to use this manual: typographical conventions ................ 10

Section 2: Installation............................................................. 13

Preparations ................................................................................ 13

Transducer Installation .............................................................. 13

Single-frequency transom installations............................. 14

Dual-frequency transom installations ............................... 14

Single-frequency trolling motor installations ................... 14

Shoot-through hull installations ........................................ 14

Selecting a Transducer Location............................................ 14

How low should you go? .......................................................... 16

Shoot-thru-hull vs. Transom Mounting................................. 16

Transom Transducer Assembly And Mounting .................... 17

Trolling Motor Bracket Installation (single-frequency only) 23

Transducer Orientation and Fish Arches .............................. 23

Shoot-Thru-Hull Preparation ................................................. 24

Hulls with Flotation Materials........................................... 24

Testing Determines Best Location......................................... 25

Shoot-thru-hull Installation ................................................... 27

Speed/Temperature Sensors ................................................. 28

Optional Speed Sensor Installation ....................................... 28

Power Connections ...................................................................... 30

Powering Your Display Unit ...................................................... 31

Power Diagram A ........................................................................ 32

Power Diagram B ........................................................................ 33

Powering a NMEA 2000 Network Bus ...................................... 33

GPS Antenna/Receiver Module .................................................. 34

Connecting to a NMEA 2000 Network ...................................... 35

NMEA 0183 Wiring (Data cable) ........................................... 36

Mounting the Unit: Bracket, In-Dash or Portable.................... 39

MMC or SD Card Memory Card Installation............................ 42

Other Accessories ........................................................................ 44

Cleaning Towel........................................................................ 44

Face Cover ................................................................................... 45

Section 3: Basic Sonar Operation ........................................ 47

Keyboard ...................................................................................... 47

Power/lights on and off ............................................................... 48

Main Menu................................................................................... 48

Pages ............................................................................................ 50

Satellite Status Page............................................................... 50

Navigation Page ...................................................................... 51

viii

Notes

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 compact, wide-screen, combination fish finder

and mapping 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 dis-

cover 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 , you have an incredible combination. ™

You won't find another combination GPS and 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 fast, with a minimum

of fuss. Like you, we'd rather spend more time boating or fishing and

less time reading the manual!

So, we designed our book so that you don't have to read the whole thing

from front to back for 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 intro-

duction to the LMS-520c and LMS-525cDF, sonar and GPS. It tells you

the basics you need to know before you can make the unit look around

and tell you where you are, or look below the surface to find some fish.

Section 2 will help you install your unit, the transducer and the GPS

antenna module. We'll show you how to get the MultiMedia Card

(MMC) correctly installed inside the unit. We'll also tell you about some

of the 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 fig-

ured out how to install the unit yourself, and you just wait can't

any longer, turn to the Quick Reference on page 55 and head

for the water!)

2

After you've gained some experience with your sonar, you'll want to

check out Section 4, which discusses more advanced Sonar Options and

Other Features.

When you come to a sonar menu command on your unit’s screen, you can

look it up in the manual by skimming over the table of contents, just flip-

ping 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 in-

troduces you to Basic GPS Operations. This section features a one-

page GPS Quick Reference on page 121.

Section 6 contains short, easy-to-scan GPS lessons that follow one an-

other 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 ex-

perience), you may want to try out some of the unit’s many advanced

navigation features. That brings us to Section 7, Advanced GPS Opera-

tions. This section contains the rest of your unit’s GPS command func-

tions, 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, just flipping

through Section 6 or scanning through the command portion of Section

7.

Your unit is ready to use right out of the box, but you can fine tune and

customize it's 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 opera-

tions. 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 it's own section in the manual! For

example, did you know your unit can look up business phone numbers,

functioning as 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 used, warranties and customer service information.

3

Specifications: LMS-520c and LMS-525cDF

General

Display: ............................5.0" (12.7 cm) diagonal high contrast color

Film SuperTwist LCD; programmable to

viewing preference.

Resolution: ......................480 pixel x 480 pixel resolution; 230,400 to-

tal pixels.

Backlighting: ..................Incandescent backlit screen with multiple

lighting levels; backlit keypad.

Input power: ...................10 to 15 volts DC.

Case size: .........................5.4" H x 6.9" W x 3.4" D (13.8 x 17.6 x 8.6

cm); sealed and waterproof; suitable for salt-

water use.

MMC slots:.......................One with waterproof door (SD card compati-

ble).

Recording:........................ GPS uses MMC & SD cards for recording trip

details and displaying charts or custom maps.

Sonar uses them to record and save sonar

chart logs.

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; menu languages selectable by user.

Sonar

Frequency: ......................LMS-525cDF: 50/200 kHz.

LMS-520c: 200 kHz.

Transducers: .....................A dual-frequency Skimmer ® transducer with

built-in temperature sensor is packed with the

LMS-525cDF. It has 35°/12° cone angles. A

single-frequency Skimmer transducer with

built-in temperature sensor is packed with the

LMS-520c. It has a 20° cone angle. Transduc-

ers operate at speeds up to 70 mph (61 kts).

Transmitter:....................3,000 watts peak-to-peak/375 watts RMS.

4

Sonar sounding

depth capability:............LMS-525cDF: 2,500 feet/762 meters.

LMS-520c: 1,000 feet/305 meters.

(Actual capability depends on transducer

configuration and installation, bottom com-

position and water conditions. All sonar

units typically read deeper in fresh water

than in salt water.)

Depth display: ................Continuous display.

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 (sensor in-

cluded with LMS-525cDF.)

GPS

Receiver/antenna:............External; LGC-2000 12 parallel channel

NMEA 2000-ready GPS/WAAS re-

ceiver/antenna.

Background map: ..........Built-in custom, detailed Lowrance map.

Contains: enhanced detail of continental U.S.

and Hawaii. Includes more than 60,000 nav

aids and 10,000 wrecks/obstructions in

coastal and Great Lakes waters. Metro ar-

eas, selected major streets/highways and in-

terstate exit services details included.

Custom mapping:...........MapCreate ™ 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.

5

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.

Graphic symbols for

waypoints or event

marker icons:..................63.

Routes: .............................100; up to 100 waypoints per route.

Plot Trails:.......................10 savable; up to 9,999 points per trail.

Zoom range: ....................39 ranges; 0.02 to 4,000 miles.

NOTE:

The above memory capacities refer only 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.

How Lowrance 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 under water basics.

Sonar is an abbreviation for SO und NAvigation and Ranging, a technol-

ogy 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 dis-

play. In simple terms, here's how it finds the bottom, or the fish:

The transmitter emits an electrical impulse, which the transducer con-

verts 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 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

6

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 per-

sonal 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 is only lim-

ited by the free space available on your MMC.

How Lowrance GPS Works

You'll navigate faster and easier if you understand how your unit scans

the sky to tell you where you are on the earth — and, where you're go-

ing. First, think of your unit as a small but powerful computer. (But

don't worry — we made the unit easy to use, so you don't need to be a

computer expert to find your way!) It 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 the unit figures its latitude

and longitude, it 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 each 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™. Some unit features — such as search-

ing for businesses and addresses — won't work without a custom Map-

Create map.

There is so much detail in our background map (and even more in

MapCreate) that we'll describe their contents and differences in Section

6, Basic GPS Operations, on page 105.

Another portion of the unit’s onboard memory is devoted to recording

GPS navigation information, which includes waypoints, event marker

7

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, erase 'em and record new ones, over and over again. These

GPS Data Files (file format *.usr) can be shared between, not only the

LMS-520c and LMS-525cDF, but other Lowrance 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, the 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. (Compare that to a floppy disk's 1.44 MB capacity!) Your unit

uses all that MMC space for two key GPS purposes. (The MMC is also

used to record sonar logs.)

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 unit’s memory. (NOTE:

No matter where they come from, GPS Data Files must be loaded from

the MMC into memory before your unit can use them.)

The other key GPS use for MMCs is storage of special high-detail, cus-

tom maps, which you can produce on your computer with our MapCre-

ate software. These MapCreate custom maps contain much greater de-

tail than the basic background map. These Custom Map Files (file

format *.lcm) not only may be shared between the LMS-520c and

525cDF, but also with other Lowrance GPS and sonar/GPS units as

well as personal computers. (For example, the exact same MMC, cus-

tom map files and GPS data files can be used interchangeably between

your gimbal-mounted unit and the hand-held iFINDER™ GPS re-

ceiver.)

Your 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 your unit does its work. You

might be ready to jump ahead to Section 2, Installation & Accessories,

8

on page 13, 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.

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 avail-

able at first, 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 govern-

ment 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, pass-

ing overhead twice daily. A series of ground stations (with precisely sur-

veyed 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 that 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.

9

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.

Like most GPS receivers, the unit doesn’t have a compass or any other

navigation aid built inside. It relies solely on the signals from the satel-

lites to calculate a position. Speed, direction of travel, and distance are

all calculated from position information. Therefore, in order it to de-

termine direction of travel, you must be moving and the faster, the bet-

ter. 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 alone is plenty accurate for route navigation, but the U.S. Federal

Aviation Administration has special aircraft navigation needs that go

beyond basic GPS. So, the FAA has developed a program to boost GPS

performance with its Wide Area Augmentation System, or WAAS. The

FAA commissioned the system on July 11, 2003.

WAAS is designed to increase GPS accuracy to within 7.6 meters vertically

and horizontally, but it consistently delivers accuracies within 1-2 meters

horizontal and 2-3 meters vertical, according to the FAA. It does this by

broadcasting correction signals on GPS frequencies. Your unit automati-

cally receives both GPS and WAAS signals.

However, there are some fringe areas of the U.S., including parts of

Alaska that do not yet receive robust WAAS coverage. Continued WAAS

development is planned to extend WAAS coverage in the years to come.

WAAS boosts 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 consis-

tently good WAAS reception, but terrain, foliage or even large man-made

structures can sometimes 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. Remember, however, that this

receiver is only a tool. Always have another method of navigation avail-

able, such as a map or chart and a compass.

Also remember that this unit will always show navigation information

in the shortest line from your present position to a waypoint, regardless

10

of terrain! It only calculates position, it can’t know what’s between you

and your destination, for example. It’s up to you to safely navigate

around obstacles, no matter how you’re using this product.

How to use this manual: typographical conventions

Many instructions are listed as numbered steps. The keypad and arrow

"keystrokes" appear as boldface type. So, if you're in a real hurry (or

just need a reminder), you can skim the instructions and pick out what

menu command to use by finding the boldface command text. The fol-

lowing paragraphs explain how to interpret the text formatting for

those commands and other instructions:

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 hori-

zontal line depth cursor on the sonar screen. The arrow keys help you

move around the menus so you can execute different commands. They

are represented by symbols like these, which denote the down arrow

key, the up arrow, the left arrow and the right arrow: ↓

↓

↓↓ ↑

↑

↑↑ ←

←

←← →

→

→→ .

11

Keyboard

The other keys perform a variety of functions. When the text refers to a

key to press, the key is shown in bold, sans serif type. 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: R POUTE LANNING. 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 your 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 M TY RAILS|ENT.

2. Press ↓

↓

↓↓ to Trail 1| ENT ENT| |

→

→→ ↓

↓

↓↓ to NAVIGATE| .

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.

Translated into complete English, step 1 above would mean: "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 would mean: "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."

12

Notes

13

Section 2: Installation

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 drill-

ing 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 so-

nar/GPS unit.

6. Install the GPS antenna and route the antenna cable to the so-

nar/GPS unit.

7. Install the power cable and route it to the sonar/GPS unit.

8. Mount the sonar/GPS unit to the bracket.

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.

15

at speeds faster than 35 mph. Typically, a good transom location on

aluminum boats is between the ribs closest to the engine.

3. The transducer should be installed with its face pointing straight

down, if possible. For shoot-thru applications: Many popular fishing

boat hulls have a flat keel pad that offers a good mounting surface. On

vee hulls, try to place the transducer where the deadrise is 10° or less.

Left, vee pad hull; right, vee hull. A pod style transducer is shown

here, but the principle is the same for Skimmers inside a hull.

4. If the transducer is mounted on the transom, make sure it doesn't

interfere with the trailer or hauling of the boat. Also, don't mount it

closer than approximately one foot from the engine's lower unit. This

will prevent cavitation (bubble) interference with propeller opera-

tion.

5. If possible, route the transducer cable away from other wiring on the

boat. Electrical noise from engine wiring, bilge pumps and aerators

can be displayed on the sonar's screen. Use caution when routing the

transducer cable around these wires.

Good and poor transducer locations.

CAUTION: Clamp the trans-

ducer cable to transom near

the transducer. This will help

p

revent the transducer from

entering the boat if it is

knocked off at high speed.

Good location

Poor angle

Poor location

Good

location

Deadrise less than 10°

°

°°

Pad Strakes

16

How low should you go?

For most situations, you should install your Skimmer transducer so

that its centerline is level with the bottom of the boat hull.

This will usually give you the best combination of smooth water flow

and protection from bangs and bumps.

Align transducer centerline with hull bottom.

However, there are times when you may need to adjust the transducer

slightly higher or lower. (The slots in the mounting brackets allow you

to loosen the screws and slide the transducer up or down.) If you fre-

quently lose bottom signal lock while running at high speed, the trans-

ducer may be coming out of the water as you cross waves or wakes.

Move the transducer a little lower to help prevent this.

If you cruise or fish around lots of structure and cover, your transducer

may be frequently kicking up from object strikes. If you wish, you may

move the transducer a little higher for more protection.

There are two extremes you should avoid. Never let the edge of the

mounting bracket extend below the bottom of the hull. Never let the

bottom – the face – of the transducer rise above the bottom of the hull.

Shoot-thru-hull vs. Transom Mounting

In a shoot-thru-hull installation, the transducer is bonded to the inside

of the hull with epoxy. The sonar "ping" signal actually passes through

the hull and into the water. This differs from a bolt-thru-hull installa-

tion (often called simply "thru-hull"). In that case, a hole is cut in the

hull and a specially designed transducer is mounted through the hull

with a threaded shaft and nut. This puts the transducer in direct con-

tact with the water.

Typically, shoot-thru-hull installations give excellent high speed opera-

tion and good to excellent depth capability. There is no possibility of

transducer damage from floating objects, as there is with a transom-

mounted transducer. A transducer mounted inside the hull can't be

knocked off when docking or loading on a trailer.

Transom

Hull bottom

Transducer

centerline

17

However, the shoot-thru-hull installation does have its drawbacks.

First, some loss of sensitivity does occur, even on the best hulls. This

varies from hull to hull, even from different installations on the same

hull. This is caused by differences in hull lay-up and construction.

Second, the transducer angle cannot be adjusted for the best fish

arches on your sonar display. (This is not an issue for flasher-style

sonars.) Lack of angle adjustment can be particularly troublesome on

hulls that sit with the bow high when at rest or at slow trolling speeds.

Third, a transducer CAN NOT shoot through wood and metal hulls.

Those hulls require either a transom mount or a thru-hull installation.

Fourth, if your Skimmer transducer has a built in temp sensor, it will

only show the temperature of the bilge, not the water surface temp.

Follow the testing procedures listed in the shoot-thru-hull installation

section at the end of this lesson to determine if you can satisfactorily

shoot through the hull.

Transom Transducer Assembly And Mounting

The best way to install these transducers is to loosely assemble all of the

parts first, place the transducer's bracket against the transom and see if

you can move the transducer so that it's parallel with the ground.

The following instructions sometimes vary depending on the mounting

bracket that came with your transducer. Single-frequency Skimmers

come with a one-piece stainless steel bracket, while dual-frequency

Skimmers come with a two-piece plastic mounting bracket. Use the set of

instructions that fits your model.

1. Assembling the bracket.

A. One-piece bracket: Press the two small plastic ratchets into the

sides of the metal bracket as shown in the following illustration. Notice

there are letters molded into each ratchet. Place each ratchet into the

bracket with the letter "A" aligned with the dot stamped into the metal

bracket. This position sets the transducer's coarse angle adjustment for a

14° transom. Most outboard and stern-drive transoms have a 14° angle.

Align plastic ratchets in bracket.

Dot

18

B. Two-piece bracket: Locate the four plastic ratchets in the trans-

ducer's hardware package. Press two ratchets into the sides of the plas-

tic bracket and two on either side of the transducer as shown in the fol-

lowing illustrations. Notice there are letters molded into each ratchet.

Place the ratchets into the bracket with the letter "A" aligned with the

alignment mark molded into the bracket. Place the ratchets onto the

transducer with the letter "A" aligned with the 12 o'clock position on

the transducer stem. These positions set the transducer's coarse angle

adjustment for a 14° transom. Most outboard and stern-drive transoms

have a 14° angle.

Insert and align ratchets.

Add ratchets to bracket and transducer.

2. Aligning the transducer on the transom.

A. One-piece bracket: Slide the transducer between the two ratch-

ets. Temporarily slide the bolt though the transducer assembly and

A

li

g

nment letters

Alignment

positions

Transducer bracket

Transduce

r

Transducer

bracket

Ratchet Ratchet

Transducer

19

hold it against the transom. Looking at the transducer from the side,

check to see if it will adjust so that its face is parallel to the ground.

If it does, then the "A" position is correct for your hull.

If the transducer's face isn't parallel with the ground, remove the

transducer and ratchets from the bracket.

Place the ratchets into the holes in the bracket with the letter "B"

aligned with the dot stamped in the bracket.

Reassemble the transducer and bracket and place them against the

transom. Again, check to see if you can move the transducer so it's

parallel with the ground. If you can, then go to step 3A. If it doesn't,

repeat step 2A, but use a different alignment letter until you can

place the transducer on the transom correctly.

Insert bolt and check transducer position on transom.

B. Two-piece bracket: Assemble the transducer and bracket as shown

in the following figure. Temporarily slide the bolt though the transducer

assembly but don't tighten the nut at this time. Hold the assembled

transducer and bracket against the transom. Looking at the transducer

from the side, check to see if it will adjust so that its face is parallel to

the ground. If it does, then the "A" positions are correct for your hull.

If the transducer's face isn't parallel with the ground, remove and

disassemble the transducer and ratchets. Place the ratchets into the

bracket holes with the letter "B" aligned with the bracket alignment

mark. Place them on the transducer aligned with the 12 o'clock posi-

tion on the transducer stem.

Reassemble the transducer and bracket and place them against the

transom. Again, check to see if you can move the transducer so it's

parallel with the ground. If you can, then go to step 3B. If it doesn't,

repeat step 2B, but use a different alignment letter until you can

place the transducer on the transom correctly.

Ratchets

20

Assemble transducer and bracket.

3. Assembling the transducer.

A. One-piece bracket: Once you determine the correct position for

the ratchets, assemble the transducer as shown in the following fig-

ure. Don't tighten the lock nut at this time.

Assemble transducer and bracket.

B. Two-piece bracket: Once you determine the correct position for

the ratchets, assemble the transducer as shown in the figure in step

2B. Don't tighten the lock nut at this time.

4. Drilling mounting holes.

Hold the transducer and bracket assembly against the transom. The

transducer should be roughly parallel to the ground. The trans-

ducer's centerline should be in line with the bottom of the hull. Don't

let the bracket extend below the hull!

Mark the center of each slot for the mounting screw pilot holes. You

will drill one hole in the center of each slot.

Drill the holes. For the one-piece bracket, use the #29 bit (for the #10

screws). For the two-piece bracket, use the #20 bit (for the #12 screws).

Nut

Metal

washer

Metal washer

Bolt

Rubber

washers

Flat washe

r

Lock washe

r

Flat washer

Nut

Bolt

21

Position transducer mount on transom and mark mounting holes.

Side view shown, left, and seen from above at right.

5. Attaching transducer to transom.

A. One-piece bracket: Remove the transducer from the bracket and

re-assemble it with the cable passing through the bracket over the

bolt as shown in the following figures.

For single-frequency Skimmer, route cable over bolt and through

bracket. Side view shown, left, and seen from above at right.

Both bracket types: Attach the transducer to the transom. Slide the

transducer up or down until it's aligned properly with the bottom of

the hull as shown in the preceding and following figures. Tighten the

bracket's mounting screws, sealing them with the sealant.

Adjust the transducer so that it's parallel to the ground and tighten

the nut until it touches the outer washer, then add 1/4 turn. Don't

over tighten the lock nut! If you do, the transducer won't "kick-up" if

it strikes an object in the water.

Transom

22

Align transducer centerline with hull bottom and attach transducer to

transom. Rear view of dual-frequency Skimmer shown.

6. Route the transducer cable through or over the transom to the sonar

unit. Make sure to leave some slack in the cable at the transducer. If

possible, route the transducer cable away from other wiring on the

boat. Electrical noise from the engine's wiring, bilge pumps, VHF radio

wires and cables, and aerators can be picked up by the sonar. Use cau-

tion when routing the transducer cable around these wires.

WARNING:

Clamp the transducer cable to the transom close to the

transducer. This can prevent the transducer from enter-

ing the boat if it is knocked off at high speed.

If you need to drill a hole in the transom to pass the connector through,

the required hole size be 1".

Caution:

If you drill a hole in the transom for the cable, make sure it is

located above the waterline. After installation, be sure to seal the

hole with the same marine grade above- or below-waterline seal-

ant used for the mounting screws.

7. Make a test run to determine the results. If the bottom is lost at

high speed, or if noise appears on the display, try sliding the trans-

ducer bracket down. This puts the transducer deeper into the water,

hopefully below the turbulence causing the noise. Don't allow the

transducer bracket to go below the bottom of the hull!

Flat-bottom hull Deep-"vee" hull

Bottom

of

hull

23

Trolling Motor Bracket Installation

(single-frequency only)

1. Attach the optional TMB-S bracket to the transducer as shown in the

following figure, using the hardware supplied with the transducer.

(Note: The internal tooth washer is supplied with the TMB-S.)

Attach motor mounting bracket to transducer.

2. Slide the adjustable strap supplied with the TMB-S through the slot

in the transducer bracket and wrap it around the trolling motor. Po-

sition the transducer to aim straight down when the motor is in the

water. Tighten the strap securely.

3. Route the transducer cable alongside the trolling motor shaft. Use

plastic ties (not included) to attach the transducer cable to the troll-

ing motor shaft. Make sure there is enough slack in the cable for the

motor to turn freely. Route the cable to the sonar unit and the trans-

ducer is ready for use.

Transducer mounted on trolling motor, side view.

Transducer Orientation and Fish Arches

If you do not get good fish arches on your display, it could be because

the transducer is not parallel with the ground when the boat is at rest

in the water or at slow trolling speeds.

Bolt

Internal tooth washer

Nut

Flat washe

r

TMB-S bracket

24

Transducer angles and their effects on fish arches.

If the arch slopes up – but not back down – then the front of the trans-

ducer is too high and needs to be lowered. If only the back half of the

arch is printed, then the nose of the transducer is angled too far down

and needs to be raised.

NOTE:

Periodically wash the transducer's face with soap and water to re-

move any oil film. Oil and dirt on the face will reduce the sensitiv-

ity or may even prevent operation.

Shoot-Thru-Hull Preparation

Hulls with Flotation Materials

The transducer installation inside a fiberglass hull must be in an area

that does not have air bubbles in the resin or separated fiberglass lay-

ers. The sonar signal must pass through solid fiberglass. A successful

transducer installation can be made on hulls with flotation materials

(such as plywood, balsa wood or foam) between layers of fiberglass if

the material is removed from the chosen area. See the following figure.

Transducer aimed

too far back Transducer aimed

too far forward

Proper transducer angle

Partial fish arches

Full fish arch

25

WARNING:

Do not remove any material from your inner hull unless

you know the hull's composition. Careless grinding or

cutting on your hull can result in damage that could

sink your boat. Contact your boat dealer or manufac-

turer to confirm your hull specifications.

Epoxy the transducer to a solid portion of the hull.

For example, some (but not all) manufacturers use a layer of fiberglass,

then a core of balsa wood, finishing with an outer layer of fiberglass.

Removing the inner layer of fiberglass and the balsa wood core exposes

the outer layer of fiberglass. The transducer can then be epoxied di-

rectly to the outer layer of fiberglass. After the epoxy cures for 24

hours, fill the remaining space with polyester resin. When the job is

finished, the hull is watertight and structurally sound. Remember, the

sonar signal must pass through solid fiberglass. Any air bubbles in the

fiberglass or the epoxy will reduce or eliminate the sonar signals.

Testing Determines Best Location

Ideally, the shoot-thru transducer should be installed as close to the

transom as possible, close to the centerline. This will give you the best

performance during high speed maneuvers.

Shoot-thru-hull transducer locations for

high speed or trolling speed operation.

Transducer location

(trolling speed)

Transducer location

(high speed)

Fill with resin

Inner hull

Epoxy to hull first Outer hull

Flotation material

Fill with

26

To choose the proper location for shoot-thru-hull mounting, follow these

testing procedures: (You may need a helper to complete these steps.)

1. Anchor the boat in about 30 feet of water. Add a little water to the sump

of the boat. Plug the transducer into the sonar unit, turn it on, then

hold the transducer over the side of the boat in the water. Adjust the

sensitivity and range controls until a second bottom echo is seen on the

display. (You'll need to turn off Auto Sensitivity, Auto Depth Range and

ASP™. Try a range setting that is two to three times the water depth.

The harder (more rocky) the bottom, the easier it will be to get a second

bottom signal.) Don't touch the controls once they've been set.

Example of a second bottom signal. Unit is in 30 feet of water, with

range set at 80 feet and sensitivity set at 87 percent.

2. Next, take the transducer out of the water and place it in the water in

the sump of the boat, face down. (The transducer face is shown in the

figure on the following page.) Notice how the signal strength decreases.

The second bottom signal will probably disappear and the bottom sig-

nal intensity will likely decrease.

3. Now move the transducer around to find the best location with the

strongest possible bottom signal. If you find a spot with an acceptable

bottom signal, mark the location and move on to step 4.

If you can't get an acceptable bottom signal, try turning up the sensitiv-

ity by three or five keystrokes and then move the transducer around

once more. If you find a spot that works, mark it and move on to step 4.

If you have to turn up sensitivity by more than five keystrokes to get a

good signal, the transducer should be mounted on the outside of the

hull. This is especially true if you have to turn sensitivity all the way

up to get a decent bottom signal.

Second bottom

True bottom

Manual range setting

90

3. The Sensitivity Control Bar appears. Press ↓

↓

↓↓ to decrease sensitivity;

press ↑

↑

↑↑ to increase sensitivity. When it's set at the desired level, press

EXIT. (When you reach the maximum or minimum limit, a tone sounds.)

The Split Frequency Sonar Chart page allows you to adjust

sensitivity separately for each window.

Digital Data/Chart

This mode shows the chart on the right side of the screen. The left side has

five digital data boxes containing: Water Depth; Water Speed (from an op-

tional speed sensor); Water Distance (distance traveled or log, it also re-

quires a speed sensor); Surface Water Temperature and Voltage.

Digital Data/Chart

Customize Page Displays

Every Page display option except Full Map (on the Map Page) has cus-

tomizable data boxes to provide constant on-screen information.

The data available from your unit is divided into categories in the Data

Viewer menu. These categories include GPS Data, Navigation, Trip

91

Calculator, Time, Sonar Data and Miscellaneous Data. You can select

items from any of these categories for display in any data box — the

category divisions are only there to help you sort through the informa-

tion.

To change the information displayed in a data box:

1. On the Page display you wish to change, press MENU|↓

↓

↓↓ to CUSTOM-

IZE|ENT. A data box name flashes, indicating it is selected.

2. Press ENT to change the box or hit ↑

↑

↑↑, ,

↓

↓↓ →

→

→→ or ←

←

←← to select another box,

then press ENT. You'll see a list of categories with "+" or "–" symbols

next to each category. A category with a "+" is expandable, meaning its

contents are hidden.

Customize Menu, with "GPS Data" and "Navigation" categories expanded.

3. Selecting the category name and pressing ENT will show the cate-

gory's contents, so you can choose items within it. An expanded cate-

gory (one with a "–" next to its name) can be collapsed to hide its con-

tents. Just select the category name and press ENT.

4. Expand any categories that might contain data you want to display.

Then press ↓

↓

↓↓ ↑

↑

↑↑ to select a different data option.

5. With the new option highlighted, press ENT to switch the contents of

the box to the new data type, then press EXIT.

6. You can now select another box to change. When you are finished

with the settings, press EXIT again to end the Customize command, and

the box name stops flashing.

A Page display can show a limited number of data boxes. You can not

turn them off or add more data boxes.

92

Flasher

The Flasher sonar page option represents a flasher style sonar com-

bined with a scrolling chart. A circular dial shows all returning echoes

at a high screen refresh rate. It uses the Colorline feature to show

weaker targets as lighter colors. The bottom depth is also shown as a

black bar across the outer circle. You can adjust the size of the chart

and the flasher windows by using the Resize Window command, which

is described in Sec. 6.

Flasher page.

Sonar with Custom Gauges

The Sonar with Custom Gauges page has a split screen with sonar on

the right side, digital gauge information on the left side. The two win-

dows can be resized to make one side bigger than the other or may be

set up to split the screen evenly.

Sonar with Custom Gauges selected on the Pages menu (left). To

change custom gauge information, access overlay data on the Custom

Gauges menu (center). Overlay Data shown menu (right).

Bottom signal

Surface clutte

r

Fish signal,

approximately

11 feet

Fish signal,

approximately

22 feet

Mærke:	JRC
Kategori:	Skibsradar
Model:	LMS-520C

JRC LMS-520C Manual

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