Lowrance LRG-1510C User Manual

INSTALLATION AND OPERATION

MANUAL

MODEL LRG-1510C

GRAYLINE® RECORDER

Printed in U.S.A.

988-0055-08

LOWRANCE

•

12000 F. SKELLY DR.. TULSA. OKLA. 74128

ELECTRONICS,

INC.

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NOTICE

Periodically

move

any

sensitivity

oil

or

wash

film

may

Transducer Face with

that

even

collect Oil and dirt on the face will reduce

may

prevent

the

GOT A PROBLEM? LET US HELP!

It

have a

you

before

help

Assistance can often be extended

problem

sending

one of our Authorized

Customer Service

Please detail the

ment

be able to save

may

If it is determined that

tions will be

provided.

SCHEMATIC DIAGRAM AND PARTS LIST

Should
rance TRUELINE

Electronics, Inc.,
sure and

SONAR INSTRUMENT

desire a Schematic

you

us the Model Number and Serial Number of

give

with

it in for

Department

problem you

RECORDER,

12000 East

your

repair.

Service Centers or the Lowrance

the inconvenience of

you

unit must be

your

Skelly Drive, Tulsa,

sounding.

sonar

by telephone

in

Tulsa,

are

experiencing.

Diagram
send

$1.00

and water to re-

soap

unit,

please give

us a chance to

or letter. Write or call

Electronics, Inc.,

OK.

(Toll-free 1-800-331-3889).

Our Service

returning your

returned,

and Parts list for

to PARTS

full

shipping

your

Lowrance

LIST,

Oklahoma 74128. Be

Depart-

unit.

instruc-

Low-

your

25

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SPECIFICATIONS

Depth Ranges

Operating Frequency:

Pulse

Length: (duration

Operating Voltage:

Output

Current

Power:

Operating

Weight

Dimension:

Minimum .

Maximum.

With Gimbal Mount

Width 121/4'

Height
Depth

—

LRG-1510C

of

pulse):

0- 30 feet

0- 60 feet

0-120

feet

0-360 feet

192 kHz
second); accuracy

0.6

percent

volts DC

to 1.8

printing density

power.

900 watts

watts

(112

8.5 lb.

51/4"

(3.9 Kg)

Instrument

Width 9½"

Height

Depth

(192,000 cycles per

is within

its.

amps depending

and

output

on

typical peak-to-peak

RMS)

Only

7½"
5¼"

INDEX

What It Is .

How It Works.

What It Tells You

Installation
Operation

Scale
Sensitivity

Suppression

Paper Speed

GRAYLINE® ©

How To Read
Paper Loading

Graphs

2
3
4
6

7
7

7

8

8

9

10

13

19

20
22

23
23

24

25

1

24

Stylus Replacement
Stylus

Maintenance

Belt

Replacement

Do's and Don'ts

Trouble

Specifications

Shooting

How to Obtain Service

p

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WHAT IT

Sonar" is an

developed
Sound

feet

—

when

second as

per

-

is

abbreviation

as a means of

transmitted

compared

_____

meaning

tracking enemy

through

sound

submarines

water — travels at

to 1100

through

SOUND

FASTER IN WATER AS IT

air.

and

ranging."

during

World War II.

approximately

DOES

navigation

TRAVELS MORE THAN 4

)DDDflflDDflDflfl) )flflflfl)

)I

It was

4800

TIMES

IN

AIR

DO SECTION

Do
Do use the

Do use the
post.

Do
Do
Do clean

paper.

a

carry

spare

tape

empty

carry a pencil

the recorded

keep

the

stylus

fuse,

sty!us

from a new roll or

cardboard core from

to make notes on the

graphs

and roll of

belt,

to attach

paper

the last roll of

paper.

for future reference.

belt and wheels with alcohol after

paper.

it to the

take-up spool.

on the

paper

every

five

take-up

rolls of

DON'T SECTION

4800 FEET PER SECOND IN WATER

In

simple terms,

transmitted into the water. When

Since the
between the transmitted

speed

an electrical

impulse

is converted into a sound wave and

wave strikes an

the

of sound in water is known

and the received echo can be measured and

signal

obstacle,

—

and constant

it

rebounds.

—

the time

the distance to the obstacle determined. An electronic sonar unit can both
send and receive the sound

them.

PRINCIPLE OF SONAR

TRANSMITTED

SIGNAL

ANDRECEIvED

((((((

waves,

(N

L

SIGNAL SENT BY

2

Fig.

The Lowrance Model LRG-1510C

cally designed

power, (112

line"

gray

that even a

identified.
Full control of the

demands of

for

watts

capability,

single

varying

can select the unit's

paper speed,

information. The

filters out false
with the

permanent

and the

signals

line function to

gray

record of what

TARGEt TIME

fishermen. It has 900 watts

sport

features

RMS)

and

fish

system

patented

provides

hovering

is at

bottom

conditions,

sensitivity setting, suppression
degree

Lowrance variable

without

provide

your

as well as

LAPSE INDICATES DISTANCE TO

recorder is a

graph

to read

easy

easy-to-read

nine inches off the bottom is

just

your finger tips

water

of

distorting

line" used to enhance

gray

the real

clear

sonar has "seen"

time, measure,

LOCATOR BOUNCES

straight

graphs

to meet the

depth

suppression system

ones,

signals

under all conditions. The

is rolled and stored inside

and record

I

BACK FROM

TARGET

compact

typical

line

and boat

level, depth range,

but is

unit

specif

peak-to-peak

recordings,

with

such

changing

speed.

the

recorded

not

synchronized

has a

clarity

easily

only

You

the case.

2

DON'T OPEN THE CASE WHEN THE UNIT

Don't
Don't store
Don't
Don't rotate the
Don't use

the

pull

forget

oily

platen assembly

any objects

to

tape

stylus

cloths,

inside

the

paper

belt

strong

down when the

the case or behind the

to the

take-up

up.

solvents or abrasive cleansers.

TROUBLESHOOTING

SYMPTOM WHAT TO DO

A.

On/Off

stylus

B.

On/Off

i-

zero

tom

C. The unit is

switch is

and

switch is

mark,

signals

"ON",

but the

have

paper

"ON",

don't move

but no echoes or bot-

ON,

but

paper

does

not move

D. Recorder marks are faint or dim D, Clean

E.

Recordedmarksareveryheavy;

is torn

paper

by stylus

A. Check

B. Be sure the transducer is

C.

E. Bend the

IS ON.

at the front,

is

stylus

viewing

core.

check connections

fuse;

at

battery; tighten power

connector

into the unit and the trans-

ged

door.

cord

plug-

duceris in contact with the water

Tape Paper

on

take-up post

stylus

to cardboard

viewing door; replace

stylus slightly

pressure

on

paper.

spoo1

the

to reduce

23

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MAINTENANCE

NOTE: The
platen assembly

the

platen

to remove

Black carbon dust is created
oil-free

pressure compressed

from
After

should be
carbon dust.

stylus may

is

when

changing

stylus.

to clean the

rag

moving parts/f

five rolls of

every

wiped

Strong

All mechanical connections

haven't
DO NOT
DO NOT wash the unit

remove salt

HIGH VOLTAGE is

attempt

electronic section.
Corrosion

splices,
checked

The face of the

periodically

oily

worked loose.

any type

appy

accumulations, dust,

should be made

occur

may

or at the

periodically

transducer,

with mild

film. This is essential to have

the water.

Periodically,
cloth

page

the rubber roller

dampened

16,

Figure 29).

with

be

damaged

down.

pulled

the

viewing

air

may

the air is

paper,

clean with a soft

solvents or abrasive cleaners should not be used.

should be checked

of lubricant to the motors or

with

running

present

in the transmittersection when the unit is ON. No

by any

at the

power plug,

battery

connections.

cleaned as

and

if mounted on the transom should be washed

water to remove

soapy

alcohol,

it

if

is

A/ways

paper

during

move the

rolls. Rememberto

the

door and metal

in front of the

to the back side

stylus

move the belt down

recording process.

platen

behind the

platen

Use a

when the

paper.

be used to blow dust out of the case and

and free of oil.

dry

the

or road

unauthorized

belt and the wheels

stylus

moistened with

rag

water.

grime

in the fuse holder or

periodically

Wiping

is all that's

person

alcohol to remove

gear

it with a

to

modify

it rides on

to be sure

trains.

cloth to

damp

necessary.

or

repairthe

power

All electrical connections should be

with 400

accumulated road

any

grit sandpaper.

grime

drive should be cleaned with a

good

on the

to

improve

necessary

contact between the transducer and

paper

the friction on the drive shaft.

of

soft,

Low

away

they

cord

or

(See

HOW IT WORKS

When the unit is turned
lightweight

stylus

transmitter is

is called the zero

Depth: 35 ft.

belt located atthe

is attached to this belt. When the

triggered

Fieh: 17 ft.

TRULINE RECORDER BOTH SEND AND RECEIVES SIGNALS. S.

RECEIVED SIGNALS ARE INDICATED ON GRAPH PAPER.

and a small mark is made at the

and

mark,

—

an

on,

right edge

represents

PAPER

TRAVEL

electronically regulated

of the

recording paper.

is at the

stylus

top

top

the surface of the water.

DRIVE

BELT

STYLUS

PULLEY

motor drives a

The

of the

of the

marking

paper,

paper.

Fig.

This

Fig.

the

3

4

The

pulse

C

• ;

stylus

reflected the echo can be read in feet

to the

A variable

the

revolution of the

stylus,
Each mark will blend into the one

target

22

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continues to move down the

stylus

is

traveling through

makes another mark on the

scale on the left side of the

depth

motor drives the

speed

will burn it to leave a

stylus

but the

will be

stylus

paper

made,

the

a

belt,

will move a small amount before the next revolution.

one

very

tiny

of the

edge

and when an echo is

water,

The

paper.

depth

by comparing

viewing

paper graph. (The paper

permanent,

black

narrow mark will be made

before,

mark at a time.

so that a

composite "picture"

while the

paper

detected,

the

of

its location on the

area.

object

is treated so that

mark.) During

the flexible

by

sound

the

which

paper

one

of the

WHAT IT TELLS YOU

Small boat sonar
examine bottom

LRG-1S1OC

bottom are
game

contours,

be shown

identified

characteristic 'arched"

roundings — layers
under

shown.

0—

—

10

—

20

—

30

given

—

fish

submerged shipwrecks

separately

—

conditions,

good

systems

contours,

far

goes

beyond

—

schools of bait fish are

there is a continuous

—

concentrations of

at

trolling speeds

signature

of water with different

and vertical movement of

are

routinely

and locate

the

ordinary.

used to measure water

fish — but the

easily

display

—

fish as close

individual fish are

which

algae,

distinguishes

Clues to the

distinguished

of

information about bottom

together

moss or

commonly

temperatures

fish, (up

capability

composition

as six inches will

plankton

recorded with a

them

from their sur-

can be detected
or

down),

from

depth,

of the

of the

solitary

can be

can be

1

60

38

5

Fig.

LOWRANCE

This is a

sample

A and 0 indicate

represents
bottom surface which

surface,
time for a sonar

doubled. If the true bottom

If the true

indicate
baitfish scattered from 4 feet to 20 feet. It is
medium size fish

of the

return to the bottom and reflect back to the receiver

large

paper graph (H)

STRAIGHT LINE RECORDER

of the

graph printout by

bottom

an echo

signal
were ten

depth

fish. The thermocline is indicated at 28 feet

by

depths

second

(a

causes the sonar

signal)

to travel to the

reading

then the echo would occur 20 feet. C and F

feet,

their arched"

indicates "zero" or the water's surface.

a Lowrance

of 16 feet and 46 feet

caused from a

signal

bottom and back to the surface has

is 16

feet,

signatures.

Straight

Line Recorder.

respectively.

hard or reflective

very

to bounce back to the water's

Therefore,

the

also

will

echo

possible

appear

(G)

to see small and

The dark line

at 32 feet.

with schools of

across the

B

the

top

4.

5. Position the new belt on

6. Close

the belt at the

Grasp
move it

other

forefinger. (See Figure 38.)

gently

to the left while

stylus

the wheels

remove the old one. BE SURE the

UP.

the front of the case. Latch

holder with the thumb and

pushing

the belt off the

by reversing

fingers

both catches on the

the

of the new

Fig.

forefinger

wheels with the

procedure

stylus

top

used to

are

pointed

of the

and

unit.

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Fig.

Fig.

35

37

The 30' scale
samples

therefore, increasing

.r' "

p'7

gives you

below).

BOTTOM

a new dimension in resolution

The LRG-1S100 does this without

life of

stylus

-Is

THIS IS WHAT A REPRESENTATIVE

and detail.

increasing

belt,

stylus, bearings

AREA WOULD LOOK LIKE ON THE 0-30' SCALE.

motor

and the motor itself.

(See

speed,

chart

Fig.

—

10'

—

25'

'—30'

6

5'

p

7. After

installing,

Figure 37)
against

the left

the stainless

leg

8. Close the front of

STYLUS BELT

High voltage

TURN THE UNIT OFF.

1.

2. Release both

the case front to

of

3. The

20

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stylus

platen assembly.
DOWN to

if the

bend the

down more

the case. Latch both catches on the

REPLACEMENT

is

present

catches on

expose

belt rides over two wheels located at the

Refer to

position

the

won't

stylus

right leg

steel

plate.

(but

—

down so that more

not so far that it

CAUTION

all the

print

way

If it still does not

digs

—

down the

pressure

all the

print

into the

top

paper, (See

is exerted
way,

paper).

of the case.

in the electronic section when the unit is

turned on.

thetop

stylus

of the case. Pull out and down on the

the

Figure

at the center of

stylus

4 on

belt.

page

3. Move
the

platen.

right edge

the front of the belt

bend

top

of the

occasional

We

pro.

from

THIS IS WHAT THE SAME AREA

0-60' SCALE.

fisherman,

encourage you

investment and to boost

your

BE SURE to insert the two rubber
on

gimbal

diameter)
gimbal

between
ment
friction to hold the unit at

bracket. The

of

grommet goes

bracket so that it is sandwiched

gimbal

(see drawings).

The LRG-1510C isa

complete

and flexible

to

bracket and sonar

The

sonar. Its controls

enough

the remainder of

study

UPPER

(SEE

side

larger

inside of

on

grommets

the desired

your boating

CHART)

grommets

(larger

instru-

provide

angle.

are

simple enough

to

satisfy

the most

this booklet to

and

fishing pleasure.

WOULD LOOK

____________________

for the

demanding

the most

get

7

Fig.

—

LIKE ON THE

0'

5

INSTALLATION

MOUNTING

convenient area is suitable for

Any
for the best

gimbal

bracket for wood screws or thru-bolts. If

viewing angle.

There are

stiffener can be used on the back side of thin

If

the desired

mounting

trial run should be
readings

are not affected.

location is closer than 18" to a

with the unit/n

made,

POWER CONNECTIONS

12 volt DC
electrical

but if
ous
the

If a

any

crimp-type

power

plastic

system.

have

you

flashes on the

battery.

longer power

hardware store.

connections which can cause
electrical

for the

power

Power

problems

dial)

cable is

connectors.

Splices

tape.

depth

may

with electrical interference

it can be minimized

required,

Simple twisting

mounting, providing

eight mounting

operation,

sounder is

be

picked up

supplied

at an

by connecting power directly

use

should be soldered. If this can't be

ordinary

of

splices may

interference.

the unit can be tilted

holes in the base of the

necessary,

fiberglass panels.

magnetic compass,

a wooden

to be sure the

from the boat's 12 volt

accessory

(indicated by

#18

lamp

or

power buss,

cord available at

done,

result in intermittent

all

Tape

splices

a

compass

extrane-

to

use

with

STYLUS REPLACEMENT

—

High voltage

1. TURN THE UNIT OFF.

is

present

2. Release both catches on the

of the case front to

3. The

platen

at

the center of the

belt rides over two wheels located at the

stylus

assembly.

in

the electronic section when the unit is

expose

Move the front of the belt DOWN to

platen.

CAUTION

turned on.

of the case. Pull

top

the

stylus

belt.

—

and

out

(See Figure 34.)

down on the

right edge

position

the

top

of the

stylus

IMPORTANT
When

installing

with the unit is attached to the center

to the

power

cable in case either is ever shorted. A
fuse to the

8

Fig.

The

positive

unit is

protected

result if

NOTICE

the

source as

cable.

power

conducter in the

from accidental

battery

connections are

power cable,

possible.

Ground

(Negative)

power

make certain that the in-line fuse

conductor of the

This will

protect

connector is

(Positive)

both the unit and the

supplied

power

cable as close

to attach the

cable is the center conductor. The

polarity

wrong. (However,

reversals and no

the unit will

damage

not

supplied

power

will

work)

34

Fig.

4.

Hold the

by starting

holder.

stylus

5. Before

it to

Figure

6. Refer to

the tabs on
the

stylus away

belt

stylus

at its left

installing

35.

Figure

stationary

and

edge

the new

stylus,

36 to be sure the

the holder. Be sure it moves

from the

edge

with

one

finger,

moving

it out

be sure it is bent

new

stylus

freely

it

is

rubbing

and remove the old

from under the tabs on the

properly by comparing

is

positioned correctly

in the two slots. If

on until it does move

not,

stylus

under

bend

freely.

19

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10. Push the

engages

11.

Close the front

Latch both catches on the

I

platen assembly

the catch inside the

of the case.

back to its

of the case.

top

of the case.

top

fl---

operating position.

(See Figure 32.)

C---

(See

Figure 33.)

Turn the unit on.

12.

Move the Chart
Speed

clockwise. Watch

the

paper long

enough

sure it is
smoothly

evenly

platen.

flutters or

paper

begins

up-hill', repeat

8.

Step

Be sure it

32

Fig.

knob

fully

to be

moving

and

across the

If the

to run

OPERATION

—

SCALE KNOB

select

recording depth.

are four

ON/OFF

positions:

AND SENSITIVITY KNOB

to turn the uniton. The

a

knob. When
information is

over
have

When

This is normal and is caused

of the

When detailed information about brush

dine is

to the illustration below to see what effect the

recorded information.

that

radio,

soft,

muddy

to be

higher.

high Sensitivity settings

water,

desired,

used to

weaker

is,

cruising,

desired,

bottoms,

making

the

Sensitivity

There

30 feet
60 feet

120 feet
360 feet

9

Fig.

—

Rotate the On/Off knob clockwise

Sensivity

signals

knob works much likethe
will be detected with

or at other times when

the

Sensitivity setting

(which produce

are

bythe returning signal reflecting

a second

trip

knob should be set at about 3/4

a second bottom

used,

to the bottom and back.

piles,

volume

higher settings

just simple

bottom-contour

can be low. In

weak

echoes),

echo will

individual fish or

Sensitivity setting

control

of the

water or

deep

the

setting

off the surface

the

point.

has on the

will

appear

thermo-

Refer

on

33

Fig.

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.t!!_!Tflr7%1T.WV_

SENSITIVITY:
ONLY

THE BOTTOM SIGNAL

IS

DISPLAYED. ALL FISH

SIGNALS ARE LOST.

/4 SETTING

Fig.

"1

10

4-

SENSITIVITY: ¾ SETTING

A.

B. THERMOCLINE

C. BAITFISH
D.

-

I—

TREE

GAME FISH
ARCHED SIGNATURES DUE TO

VERY SLOW BOAT

SCHOOL

(NOTE:

ELONGATED

SPEED)

Fig.

ii

8. Draw the end

friction
core.

housing.)

roller,

(See Figure 30.) (Hint:

of the

over the

across the face of the

paper

take-up core,

small

and

strips

it

tape

of

tape may

platen,

squarely

be stored inside

around the

to the

take-up

Fig.

30

Recording

complished

higher.
information about this

SUPPRESSION KNOB — Is used to reduce interference
Noise,

electrical

disturbed

could
Fortunately,

signals. Advancing

these

This

pression
separate

page
Advance the knob

unwanted noise marks. Most of the time at low or
suppression

PAPER SPEED KNOB — Controls the

detail when

the

paper speed

maximum. This will show

speed
When

individual fish with an arched"

at

trolling speed

Refer to the section Arched

in

electronic

source,

terms,

(such

with the

important

is

any

as the

engine's ignition system),

Sensitivity

Signatures,"

function of

undesired

water which is called cavitation noise. In both

produce

unwanted,

patented design

unwanted marks on the

noise

pulses

short

are

the

Suppression

pulses

is exclusive with Lowrance.

settings,

the

graph

paper. (See page 11, Figure

relatively

short in time

knob will cause the

without

record becomes coarse and the

reducing

fish from the bottom or from other fish

12,

Figure 22.)

Therefore,

selling only

the lower the

as far as

necessary

suppression selling

will be needed.

trolling

and

knob

information from

charting

on the 360' scale in

looking

up

for

at least

proper

being compressed. (See

speed

or when

fish,

half-way.

fish arches at low

water,

deep

signature

your

signal.

the

of the chart

running

For best

the

can

knob at the

on

recorder,

It

compared

sensitivity

However,

will

usually

3/4

page

can be caused

or

air

by

cases,

system

with

be decreased.

to remove the

trolling speeds,

paper.

at

high speed,

detail,

speeds

'How to Read

paper speed

turn it

and

be ac-

or

point,

10

for more

from noise.

an

by

bubbles in

the noise

to real sonar

18.)

to

reject

in

any way.

high sup-

to

ability

(See

the better.

erratic,

no

For

good

turn

to

up

keeps high

Graphs.")

should be

9. Hold the

amount of tension on the
(See Figure 31.)

take-up spool,

and turn the

It should be

paper.

supply spool

snug against

clockwise to

put

the

a small

platen.

31

Fig.

17

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6.

Remoove
Align

(See Fig. 28)
into

NOTE: Both

However,

take-up

notches should be
LPG-603 chart

when

sary

LPG-602

the

empty supply

core from the

the two notches in the core with the tabs on the

Push

the

paper

place.

LPG-602 and LPG-603 chart

to use

side of the chart

the

1/4"

comes with the notches so no modification is neces-

paper

the

using

paper

and LPG-603 chart

core from the LPG-602 chart

paper

drive,

wide

core on the

paper

chart drive without modification.

Side ifl the same manner.

right

lowertake-up spool.

retainer knob in and rotate it until it locks

can be used in this unit.

paper

notches must be cut into the core. These

3/16"

by

take-up

can be used on the

on both sides of the core.

deep

side of the

paper

supply

on the

paper

drive. Both

side of the

turned down to no more than

between

stylus

strikes,

the

half-way

paper

also be turned down to conserve

cerned with fine detail.

r

p.'

for the best record. If

is

running

paper

too fast. The

when not

gaps appear

paper speed may

looking

for fish or con-

,/'

•

b

L. -

BOULDERS/LARGE ROCKS

GRAYLINE OFF"

Fig.

12

BOULDERS/LARGE ROCKS Ag. 13
GRAYLINP:

"ON"

r:

I

I'-..'

7. Put a fresh roll of

spool

paper

end

must

caps

spool

on the

paper

in

position

supply

side

on the

(right)

off the bottom of the roll.

w

centering posts

of the

platen assembly.

(See Figure 21.)

of the

paper

The

r is.

GRAYLINE®: 'OFF'

A. FISH

B. TREES

C. FISH IN TREES

D. BAIT FISH SCHOOL

GRAYLINE®

',,-,

-

outline the
and

brush;

bottom returns

Hg.

29

Arrow indicates friction roller

or

weedy

gray

etc. In

control

bottom

line. Do not

water less

knob.

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/'

—C

14

Fig.

ON/OFF KNOB

bottom contour which

it can

also

a

give

very Strong signal

returns a weaker
advance the

than

30',

—

clues

control too far or it

click

just

GRAVLINP: "ON"

A. FISH

B.

TREES

C. FISH IN TREES
D. BAIT FISH SCHOOL

The

GRAYLINE® function

otherwise

might

to the

composition

a

causing

signal

wide

which is

emphasized

will

the knob "on"

be hidden

of the

line. A

gray

line on

gray

—

do not

can be used to

beneath

bottom. A hard

with a narrow

advance the

soft,

fish,

trees

muddy

trees,

HOW TO READ GRAPHS

"ARCHED

is that

separates

shown below. The distance to

a fish when

sound is shown as

the

fish

SIGNATURES"

it can record individual fish with a characteristic arched mark that

them from their

it

moves into the sonar's cone of

'A" in

has moved to the center of the

the distance to it will be
and as

will increase

it moves out of the

as shown in line "C".

again

—

stationary

the

drawing.

shorter, (line "B"),

cone,

A remarkable

surroundings.

When

cone,

the distance

advantage

The reason for this is

of the LRG-15100

5. To remove the full

knob until it

removed from the

snaps

take-up

roll,

out.

(See Figure 26.)

paper spool

in and rotate the left

push

The roll can now be

end

caps. (See Figure 27.)

paper

retainer

easily

If a

partial

time on

but does not curve back

up
is because the transducer is not

aimed

Sharp,
knob is set at the 3/4

arch occurs most of the

unit

your

straight

well-defined

down.

mark curves

(the

signatures

point

down),

it

16

Fig.

will occur most often when the

or

higher. (See (C), Figure 17.)

Remember, too,

that there must be some movement between the fish and boat to
the arched mark.

17

Fig.

0—

—

20

—

30

—

40

—

50

—

60

THERMOCLINES — The

constant

junction

from

of a warm and cool

to bottom.

top

temperature

Layers

of water is called a thermocline. The

layer

and thickness of the thermocline can

lakes there

deep
important

Many

suspend just

to the fisherman because

times bait fish will be above the thermocline while

below it.

be two or

may

(See (G), Figure 17.)

more,

Your Lowrance Model LRG-1510C can detect this invisible

but the

higher.

Sensitivity

knob will

probably

of water in the lake is seldom

of

different

vary

at different

they

have to be set at the 3/4

temperatures form,

with the season or time of

depths.

are areas which fish are active.

Thermoclines are

larger game

layer

in the

Sensitivity

develop

and the

depth

In

day.

fish

water,

or

point,

1

Fig.

27

15

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3. Move the

position

the belt

the

up

belt

stylus

marking stylus

—

the

stylus may

SPECIAL NOTE: The

down unless the

pulled

stylus

4. Pull out and down on

expose

25

Fig.

the

paper spools. (See Figure 25.)

DOWN,

(on

the

on the back side of the

be

damaged.

stylus may

be

damaged

right

side

of the

platen.

if the

has been moved to the back side of the

the tab at the

center of the

top,

viewing area),

NEVER move

platen assembly

platen.

platen assembly

to

is

to

High Speed (46 M.P.H.)

SUPPRESSION: OFF
SENSITIVITY: ON

NOTE POOR RECORD CAUSED

—

1/2 POSITION

BY NOT USING SUPPRESSION

WHEN AT HIGH SPEED.

18

Fig.

High Speed (46 M.P.H.)

SUPPRESSION: ON
SENSITIVITY:

ON

—

ADEQUATE SETTING

—

POSITION

1/2

I .

flg.1g

A. JIGGING A 1¾ oz. HOPKINS

'SPOON IN SUBMERGED TREE.

B. FISH SIGNALS

VERY SLOWLY

C. BAIT FISH

(BOAT

OVER

DRIFTING

FISH).

'1

SCALE: 0 TO 60 FEET

SPEED: SLOW

PAPER

SUPPRESSION: OFF

DEPTHS: RECORDED FROM

INCHES TO 7'/2 FEET

.:y ...:wfl®

M¼&VM I

18

IA

20

Fig.

GRAYLINE®: 'OFF"

A. FISH

14

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ON OR NEAR BOTTOM

GRAYLINE®:

A. FISH ON OR NEAR BOTTOM

"ON"

tr\

____

-.

PAPER LOADING

—

CAUTION

1

High voltage

is

present

in the electronic section when the unit is

turned on.

—

/\t'

"N\2_

—

-

-

P

21

Fig.

A. FISH

B. JIGGING A

SUPPRESSIONz TOO HIGH SUPPRESSION: PROPER SElliNG

(NOTE

SCHOOLS OF BAIT FISH ARE ELON- SCHOOLS OF BAIT
GATED AND RUN

BOTTOM.)

DRIFTING UNDER BOAT.

FISH

MOVED FROM 13½ FEET

TO 21

FEET TO 12 FEET WHILE

DRIFTING/SWIMMING WITHIN

THE

CONE OF SOUND.

OFF 8011DM.

SCALE: 0 TO60 FEET
GRAYLINE! "ON"

THAT RECORDER SIGNALS FROM

LEAD-HEAD LURE

TOGETHER WITH THE

A. A

FISH SUSPENDED UNDER BOAT

B. FISH SWIMMING UP TOWARDS BOAT

C. SCHOOL OF BAIT FISH
D. SURFACE CLUTTER

SCALE: 0 TO 60 FEET

GRAYLINE®: "OFF"

Fig.22

DISTINCT INDIVIDUAL

(NOTE

FISH.)

1. TURN THE UNIT

2.

Release both catches on the

of the case front to

C

C

OFF

expose

I

of the case. Pull out and down on the

top
the

platen assembly. (See Figure 24.)

Fig.

top

23

.1

1

END-OF-PAPER MARKER

has a red line

2 to 3

feet before the end of

printed

at the bottom of

—

The

the

paper (See

graph paper

the

paper

to

Figure

used in the LRG-1510C

when there is

signify

23 on

Page 13.)

only

/

24

Fig.

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13