Furuno Lc-90 mark-ii User manual

|S|

0.

;

OM-E

4300-QH

OINNERS

MANUAL

loran

c

navigator

MODEL

LC-90

FURUNO

ELECTRIC

CO.,

LTD.

NISHINOMIYA,

JAPAN

8806200KY(

87D)

PftMTEO

»

JAPM

TABLE

OF

CONTENTS

************

INTRODUCTION

Congratulations

on

your

choice

of

the

Furuno

LC-90

Loran-C

navigator.

We

are

confident

that

you

will

enjoy

many

years

of

operation

with

this

fine

piece

of

equipment.

For

over

30

years

Furuno

Electric

Company

has

enjoyed

an

enviable

reputation

for

quality

and

reliability

throughout

the

world.

This

dedication

to

excellence

is

furthered

by

our

extensive

global

network

of

agents

and

dealers.

The

LC-90

Loran-C

receiver

is

just

one

of

many

Furuno

developments

in

the

field

of

navigation.

Its

compact

size

and

ease

of

installation

and

operation

make

it

suitable

for

use

on

a

wide

variety

of

vessels.

As

with

most

modern

instruments,

time

and

experience

are

required

to

reap

maximum

benefit

from

your

new

receiver.

To

help

you

meet

this

end

as

quickly

as

possible,

this

manual

is

laid

out

in

as

"user

friendly"

a

manner

as

possible.

The

first

section

covers

Basic

level

operations

and

later

sections

cover

Intermediate

and

Advanced

operations.

This

unit

is

designed

and

constructed

to

ensure

the

user

of

many

years

of

trouble-free

operation.

However,

to

obtain

optimum

performance

from

this

equipment,

we

ask

that

you

read

and

follow

the

recommended

procedures

for

installation,

operation

and

maintenance.

No

machine

can

perform

to

the

utmost

of

its

ability

unless

it

is

installed

and

maintained

properly.

We

would

appreciate

feedback

from

you,

the

end-user,

about

whether

we

are

achieving

our

purposes

in

this

manual.

Thank

you

for

considering

and

purchasing

Furuno

equipment.

CAUTION

Although

your

Loran

C

receiver

is

capable

of

providing

very

accurate

position

data,

no

single

navigational

device

should

ever

be

solely

relied

upon.

Position

information

obtained

from

Loran-C

should

always

be

doublé-

checked

against

other

sources

such

as

radar,

visual

and

celestical

sightings,

sounding

measurements,

etc.

to

verify

the

reliability

of

the

data.

FEATURES

.

SPECIFICATIONS

.

ELEMENTARY

THEORY

Basic

Navigation

How

Loran-C

Works

.

OPERATIONAL

OVERVIEW

POWER

ON/OFF

and

DIMMER

.

.

NUMERIC

KEYS

.

OPERATING

MODE/FUNCTION

KEYS

.

OTHER

KEYS

.

SUMMARY

OF

MODES

AND

FUNCTIONS

Primary

Modes,

Data

Readouts:

.

Primary

Modes,

Data

Entry:

..

Secondary

(#)

Functions:

.

Typical

Mode

Screens

.

Typical

Function

Screens

.

INSTALLATION

GENERAL

MOUNTING

CONSIDERATIONS

.

DETAILED

INSTALLATION

INSTRUCTIONS

Antenna

Coupler

unit

Installation

.

Display

Unit

Installation

.

Power

connection

.

Ground

connection

.

TESTING

AFTER

INITIAL

INSTALLATION

HOW

TO

COMBINE

WITH

AUXILIARY

EQUIPMENT

1

2

4

6

10

10

11

11

11

12

13

14

15

16

17

19

20

20

20

24

BASIC

LEVEL

OPERATIONS

TURNING

THE

UNIT

ON

AND

OFF

.

INITIALIZING

THE

NAVIGATOR

FOR

YOUR

OWN

GEOGRAPHICAL

AREA

Clearing

the

Memory

.

Initializing

Latitude/Longitude

(Function

#1)

.

READING

SPEED

AND

COURSE

(S/C

Mode)

.

Manual

Entry

of

Magnetic

Variation

(Function

#4)

.

True

Bearings

(Function

#4)

.

SETTING

THE

AVERAGING

TIME

(Function

#3)

.

AUTOMATIC

ASF

(Function

#4)

.

DIMMER

.

26

26

26

28

29

29

30

30

31

SUMMARY

OF

BASIC

OPERATIONS

u

i

INTERMEDIATE

LEVEL

OPERATIONS

USING

ASF

WHEN

ENTERING

TD'S

FOK

WAYPOINTS

61

ENTRY

OF

A

POSITION

INTO

A

WAYPOINT

Waypoint

Entry

by

Latitude/Longitude

Coordinates

(WPT

Mode):

.

33

Waypoint

Entry

by

TD's

(WPT

Mode):.

34

Waypoint

Entry

of

Present

Position

(EVT

key

in

WPT

Mode):

.

36

Waypoint

Entry

by

Range/Bearing

From

Present

Position

(CLC

Mode):

37

SELECTING

WAYPOINT(S)

FOR

USE

WITH

OTHER

MODES

AND

FUNCTIONS

Selection

of

a

Destination

WP

from

Present

Position

(NAV

Mode):

...

38

Specification

of

a

Pair

of

Waypoints

("From'’

&

"To")

(NAV

Mode):

..

39

RANGE

AND

BEARING

CALCULATIONS

(R/B

and

CLC

Modes)

Simple

Range

and

Bearing

from

Present

Position

to

a

WP

(R/B

Mode):

39

Range

and

Bearing

Between

Two

Waypoints

(CLC

Mode):.

40

CROSS-TRACK

ERROR

FUNCTION

(XTE

Mode)

..

41

VELOCITY

TO

DESTINATION

(VTD)

AND

TIME

TO

GO

(VTD

Mode)

...

42

ALARM

FUNCTIONS

(ALM

Mode)

Off-course

Alarm

.

44

Border

Alarm

.

44

Arrival

Alarm

.

45

Anchor

Watch

.

45

ROUTE

FUNCTIONS

Storing

a

Route

(PLN

Mode):

.

47

Following

a

Route

(NAV

Mode):

.

48

Temporarily

Deselecting

a

Waypoint

in

a

Route

(PLN

Mode):

.

49

EVENT

MEMORY

Storing

Present

Position

into

an

Event

Memory

.

50

Storing

Present

Position

into

a

Waypoint

Memory

(WPT

Mode):

51

CONVERTING

COORDINATES

(WPT

Mode)

.

51

ADVANCED

LEVEL

OPERATIONS

WARNING

INDICATORS

.

53

SNR

Indicator

(Function

#6)

53

CYC

Indicator

(Function

#6)

54

ECD

(Function

#6)

54

Deviation

(Function

#6)

54

Audible

SNR

(Function

#7)

55

BLINK

Indicator

.

56

Power

Failure

Indicator

.

56

MANUAL

CONTROL

OF

LORAN

RECEPTION

Manual

Cycle

Selection

(Function

#5)

.

56

Manual

Notch

Filter

Setting

(Function

#9)

.

57

MANUAL

POSITION

OFFSET

CORRECTIONS

L/L

Corrections

(Function

#2)

59

TD

Corrections

(Function

#2)

61

MANUAL

GRI/SLAVE

SELECTION

(Function

#1)

.

TD

Gradients:

.

Angle

of

Crossing:

.

HOLDING

THE

TRACKING

POINT

(Function

#7)

.

SELECTING

OUTPUT

DATA

FORMAT

(Function

#3)

.

■

TUNING

INDICATION

(Function

#8)

.

■

TROUBLESHOOTING

Self-check

1

.

Self-check

2

.

SCHEMATICS

APPENDIX

A

CHARTS

OF

VARIOUS

LORAN-C

CHAINS

SHOWING

RECOMMENDED

TD

PAIRS

62

62

63

64

64

65

66

66

m

IV

FEATURES

The

LC-90

has

a

large

variety

of

functions,

all

contained

in

a

rugged

die-

cast

aluminum

case

that

is

corapact

enough

to

fit

almost

any

size

of

boat.

Sealed-membrane

touchpads

provide

positive,

splashproof

Control

of

all

functions

displayed

on

the

large

five

line

LCD

(Liquid

Crystal

Display)

display.

Both

the

touchpads

and

the

LCD

display

have

variable

backlighting

for

nighttime

operation,

and

touchpad

operations

are

confirmed

by

an

audio

tone.

The

LC-90

features

virtually

"hands-off"

autornatic

operation

once

it

has

been

initialized

for

a

specific

geographic

area,

since

selection

of

the

proper

GRI

and

the

optimum

slave

secondaries

is

autornatic,

as

is

ASF

compensation

(Additional

Secondary

Factor)

for

accurate

Latitude/Longitude

readout,

autornatic

Magnetic

Variation

for

magnetic

bearing

readouts,

and

six

autornatic

notch

filters

to

eliminate

interference.

Each

autornatic

function

however

may

be

manually

overridden

if

the

operator

desires.

Entry

and

readout

for

all

position

functions

may

be

by

either

Latitude

and

Longitude

or

by

TD

r

s

(Time

Differences)

for

maximum

flexibility.

Navigation

functions

built

into

the

LC-90

include:

•

Position

readout

in

Latitude/Longitude

or

Time

Differences

(TD's).

•

Speed

Made

Good

and

Course

Made

Good.

•

Velocity

To

Destination

and

Time

To

Go

to

destination.

•

Range

and

Bearing

to

a

waypoint

and

Range

and

Bearing

from

waypoint

to

waypoint.

Bearing

can

be

either

True

or

Magnetic,

with

autornatic

Magnetic

Variation

built-in.

•

Cross-Track

Error,

Direction

to

steer

to

get

back

to

courseline,

Course

Offset,

and

Range

to

destination

on

one

display

screen.

•

Entry

of

waypoint

by

Latitude/Longitude,

TD's,

by

Range/Bearing

from

present

position,

or

at

Present

Position.

•

Route

Planning

and

autornatic

Route

following.

•

Alarm

limit

setting

for

Cross-Track

Error

alarm.

Border

alarm,

Arrival

alarm,

and

Anchor

Watch

alarm.

•

Display

of

signal

parameters:

SNR

(visual

and

audible

indications),

ECD,

tracking

point,

and

interference

frequency

and

level,

with

six

autornatic

notch

filters

built-in.

•

Display

of

operational

parameters:

GRI

slave

selection,

ASF

or

manual

correction

factors,

auxiliary

data

output(s),

and

Event

memory

contents.

LC-90

SPECIFICATIONS

Receiving

Frequency:

Receiver

Sensitivity:

Dynamic

Range:

Differential

Dynamic

Range:

Interference

Rejection:

Tracking:

Tracking

Speed:

Settling

Time:

Display

Resolution:

Alarm

Indications:

Computational

Base:

Output

Signals

to

Ext.

Equipment:

Ambient

Temperature

Range:

Power

Supply:

Weight:

100

KHz

1

microVolt/m

UO

dB

80

dB

Six

autornatic

notch

filters

built-

in.

The

se

may

be

manually

operated

if

desired.

Master,

plus

5

secondaries

(max.)

80

kts

5

min.

nominal

(depends

on

Loran

signal

conditions.)

TD:

0.1

microseconds.

L/L:

0.01

minutes.

Range:

0.01

n.m.

Audible

and

visible,

including

Cross

Track

Error,

Arrival,

Border

and

Anchor

Watch

alarms.

WGS-72

Range/Bearing:

Great

Circle.

Furuno

CIF

for

course

plotter,

printer,

scanning

sonar,

color

video

sounder;

NMEA

0180

simple

format

for

autopilot;

NMEA

0183

complex

format

for

plotters.

Display

Unit:

0

to

50

deg.

C.

Ant.

Coupler:

-30

to

70

deg.

C.

10-42

VDC,

universal,

9w.

110/220

VAC,

50-60

Hz,

with

external

rectifier.

Display

Unit:

2.3

kg

Antenna

Coupler:

0.6

kg

1

2

COMPLETS

SETS

Name

Main

Unit

_

Antenna

Coupler

Installation

Materials

Accessories

_

Spare

Parts_

INSTALLATION

MATERIALS

3

ELEMENTARY

THEORY

SECTION

The

word

"LORAN"

is

an

acronym

meaning

LOn

g

RAn

g

e

Navigation.

The

basic

principles

of

Loran

were

developed

during

World

War

II,

and

the

system

implemented

during

that

time

was

known

as

the

Loran

A

system.

The

superior

Loran-C

system

was

developed

later

during

the

1960's

and

was

put

into

widespread

service

during

the

late

1970's.

Loran-C

is

one

of

several

important

radio

navigation

systems

in

use

by

mariners

throughout

the

world

today.

Loran-C

may

be

thought

of

as

a

medium-range

system

since

it

usually

covers

out

to

a

maximum

of

1200

miles

from

the

transmitting

station.

For

very

close-in,

precision

work,

portable

microwave

positioning

systems

are

often

employed

by

such

users

as

the

offshore

oil

industry,

and

for

short

range

medium-accuracy

work.

Decca

navigation

systems

are

used

in

some

parts

of

the

world.

For

transoceanic

voyages,

Sateliite

Navigation

and/or

Omega

receivers

are

used

to

provide

the

sort

of

coarse

accuracy

that

is

suitable

on

the

open

sea.

In

-

ot

her

word

s,

it

is

rarely

necessary

to

know

your

position

down

to

the

nearest

meter

when

on

an

ocean

voyage,

provided

that

you

are

reasonably

certain

that

you

are

within

the

shipping

låne

and

not

in

any

danger

of

running

aground

on

some

nearby

atoll.

The

Loran-C

system

was

designed

and

established

to

provide

excellent

accuracy

in

the

region

known

as

the

"Coastal

Confluence

Zone,"

or

CCZ

as

it

is

often

called.

This

region

extends

from

the

shoreline

seaward

to

the

100

fathom

curve,

or

50

nautical

miles,

whichever

is

greater.

Loran-C

system

accuracy

is

often

capable

of

providing

a

reliable

fix

within

30

meters

of

one's

actual

position,

but

more

typically,

accuracy

of

about

100-200

meters

is

possible

throughout

the

coverage

area.

However,

system

repeatability,

that

is,

the

ability

to

return

to

the

same

spot

consistently,

is

usually

on

the

order

of

20-30

meters.

Quite

often

it

is

even

better

than

that.

Basic

Navigation

The

essential

idea

behind

a

scheme

of

positioning

on

the

globe

is

that

any

particular

point

on

the

earth's

surface

can

be

uniquely

described

by

the

intersection

of

two

lines:

Latitude,

girdling

the

earth

horizontally

(laterally)

and

Longitude,

girdling

the

earth

vertically.

Examine

the

section

of

chart

shown

next

page

(Fig.

1)

depicting

an

area

off

Yokohama

Japan.

One

can

see

the

parallels

of

Latitude

running

East

and

West

horizontally,

and

the

meridians

of

Longitude

running

vertically

North

and

South.

Overprinted

on

this

chart

are

so-called

Loran-C

Lines

Of

Position

or

TD's

(Time

Differences)

as

they

are

more

commonly

known.

(We'll

get

into

why

they

are

called

TD’s

later;

suffice

it

to

say

for

now

that

a

Loran-C

receiver

will

give

you

these

numbers

and

that

you

can

use

these

numbers

to

find

your

position.)

Note

that

the

TD

lines

run

at

a

variety

of

angles

with

respect

to

the

lines

running

North/South

or

East/West.

They

are

in

faet

actually

curved

lines,

segments

of

hyperbolas,

but

this

is

difficult

to

see

on

this

small

section

of

4

Fig.

1

Loran-C

Chart

off

Yokohama

chart.

These

TD

lines

are

labeled

with

numbers

in

units

of

microseconds

on

the

outer

edges

of

the

chart.

The

spacing

between

adjacent

TD's

will

vary

depending

on

the

scale

of

the

chart

as

well

as

the

section

of

geography

being

covered.

Don't

worry

about

these

details

just

yet,

but

note

that

in

this

particular

example

the

spacing

between

adjacent

TD's

is

either

100

or

200

microseconds.

Just

note

that

for

any

one

position

on

the

chart

(that

is,

at

any

one

particular

Latitude

and

Longitude)

there

is

at

least

one

pair

of

Loran-C

TD's

that

cross

each

other.

There

may

in

faet

be

more

than

one

pair

of

TD's

that

cross

each

other

at

our

one

point

of

interest.

Some

of

them

may

give

you

better

accuracy

than

others.

Again,

we'll

delve

in

to

that

in

more

detail

later.

As

an

example,

let's

find

a

point

on

the

chart

and

compare

the

position

both

by

Latitude/Longitude

and

by

Loran-C

TD's.

At

a

Latitude

of

33

degrees,

52

minutes

North

and

a

Longitude

of

139

degrees,

35

minutes

East

you

should

find

the

Southeast

corner

of

Mikura

Jima

Island.

This

position

corresponds

to

the

Crossing

of

the

two

TD's

lines

of

36800

microseconds

and

60600

microseconds.

Note

that

a

third

TD

crosses

this

position

also,

but

that

the

exact

line

isn't

printed

on

the

chart

explicitly—it

is

necessary

to

interpolate

between

lines

that

actually

are

printed

in

order

to

get

this

TD,

and

.by

so

doing

we

would

come

up

with

a

TD

of

approximately

17750

microseconds.

Now,

let's

consider

in

more

detail

the

way

Loran-C

actually

works.

HOW

LORAN-C

WORKS

The

Loran-C

system

is

a

"pulsed"

system

whose

fundamental

assumption

is

that

the

speed

of

propagation

of

a

radio

wave

is

constant

anywhere

in

the

area

of

coverage

of

the

system.

This

assumption

is

actually

subject

to

some

corrections,

but

we

will

assume

for

the

sake

of

this

discussion

that

the

speed

of

a

Loran-C

signal

is

actually

constant.

Since

distance,

time

and

speed

are

all

related,

and

since

we

have

assumed

that

the

speed

of

the

signal

is

constant,

if

we

can

devise

some

means

to

measure

the

time

that

it

takes

for

a

signal

to

arrive

from

a

distant

transmitter,

we

can

easily

calculate

the

distance

the

signal

has

travelled

to

get

to

us.

Thank

goodness

for

modern

electronics,

for

it

provides

means

for

making

very

precise

time

measurements,

down

to

the

order

of

tenths

of

millionths

of

seconds.

6

A

simple

Loran-C

system

is

shown

in

Fig.

2,

consisting

of

a

"master"

transmitting

station

and

two

"slave"

stations.

This

is

the

simplest

configuration

used.

In

practice,

most

of

the

chains

in

the

world

consist

of

three

or

four

slave

stations

associated

with

each

master.

Note

that

the

lines

drawn

connecting

the

master

and

each

of

the

two

slaves

are

known

as

"baselines."

To

illustrate

the

basic

idea

behind

the

Loran-C

system

let

us

take

a

simple

case,

where

the

boat

with

the

Loran-C

receiver

is

located

on

one

of

the

baselines

and

is

in

the

middle

between

the

master

and

the

slave.

If

the

transmitters

were

both

to

transmit

simultaneously,

the

time

taken

for

the

signals

from

the

master

transmitter

to

arrive

will

be

the

same

as

that

for

the

signals

from

the

slave

to

arrive.

In

other

word

s,

the

difference

in

arrival

time

will

be

zero.

If

the

boat

is

moved

so

that

the

time

difference

of

signal

arrival

from

master

and

slave

is

kept

constant

at

zero,

then

the

plot

of

these

movements

will

be

a

straight

line

halfway

between

the

slave

and

the

master

stations.

This

line

will

be

perpendicular

to

the

basefine.

The

line

of

constant

time

difference

is

known

as

a

Line

of

Position,

or

LOP

for

short.

Other

LOP'

s

can

be

generated

for

conditions

where

the

time

difference

isn't

exactly

zero,

and

these

LOP's

will

form

hyperbolas

rather

than

the

straight

line

in

our

simple

case.

(Radio

navigation

systems

such

as

Loran-C

are

often

referred

to

as

"hyperbolic

navigation"

systems

for

this

reason.)

If

the

master

and

its

associated

slaves

were

all

to

transmit

simultaneously

on

the

same

frequency,

the

receiver

would

not

be

able

to

distinguish

which

station

it

was

listening

to

in

the

resul

tin

g

up

roar.

The

stations

therefore

are

arranged

to

transmit

in

a

specific

sequence

of

pulses,

with

very

precisely

defined

time

delays

between

the

transmissions.

So,

for

our

simple

case

above

where

the

LOP

is

in

the

middle

of

the

baseline,

the

time

difference

is

no

longer

zero,

but

is

some

specific

value

of

TU.

The

receiver's

job

is

to

use

the

start

of

reception

of

the

master

signal

as

a

reference

time

to

start

its

internal

stopwatch.

When

the

start

of

the

slave

signal

is

detected,

the

receiver

in

essence

stops

its

internal

stopwatch,

notes

the

time

difference,

and

displays

it

to

the

operator

as

a

TD.

In

order

to

determine

where

one

is

located

on

any

particular

Line

of

Position,

another

LOP

is

needed

to

intersect

the

first

one.

The

Loran-C

receiver

thus

must

track

more

than

one

slave

at

the

same

time.

Most

modern

receivers

are

capable

of

tracking

all

slaves

available

in

the

chain

simultaneously.

The

interval

of

time

between

the

start

of

the

master

transmission,

the

series

of

slave

transmissions

and

the

next

master

transmission

that

repeats

the

whole

sequence

is

called

the

Group

Repetition

Interval,

or

GRI.

Each

Loran-C

chain

in

the

world

has

a

unique

GRI

assigned

to

it,

and

even

though

all

Loran-C

transmitters

work

on

the

same

frequency

(100

KHz),

they

can

all

be

sorted

out

by

GRI.

You

will

remember

that

the

Time

Difference's

(TD's)

are

measured

in

microseconds

(millionths

of

a

second).

Further,

the

designers

of

the

Loran-C

system

have

assigned

an

identifying

letter

code

to

each

slave

station

in

a

chain.

These

are

called

either

X,

Y,

W,

or

Z.

Now

look

back

at

the

section

of

chart

in

Fig.

1

that

shows

part

of

the

area

near

the

coast

of

Japan.

You

can

now

better

appreciate

why

the

TD's

are

lab

el

ed

as

they

are.

The

GRI

in

the

label

comes

first,

then

the

identifying

code

letter,

and

then

the

time

difference

in

microseconds.

Your

Loran-C

receiver

is

considerably

more

sophisticated

than

the

simple

TD-only

receivers

we

have

been

describing

here.

It

is

capable

of

computing

Latitude

and

Longitude

directly

from

these

TD's.

This

is

a

complex

calculation,

and

again

the

fundamental

assumption

made

is

that

the

velocity

of

propagation

of

the

signal

is

constant,

While

this

is

true

for

propagation

over

seawater,

the

velocity

is

altered

slightly

when

the

signals

travel

over

land.

Over

land,

the

velocity

is

affected

by

such

factors

as

the

conductivity

of

the

soil

and

the

features

of

the

terrain.

These

effects

are

all

lumped

together

under

the

title

of

"Additional

Secondary

Factors,"

or

ASF.

These

factors

cannot

be

modeled

exactly

in

the

TD

to

Latitude/Longitude

mathematical

conversion.

The

LC-90

however

has

TD

offsets

built-into

it,

describing

deviations

from

the

ideal

grid.

The

offsets

were

actually

measured

at

sea.

The

LC-90

can

automatically

take

these

warpages

into

account

to

give

more

accurate

computation

of

Latitude

and

Longitude

than

can

a

receiver

without

this

automatic

ASF

correction.

Note

that

the

TD

grid

s

on

a

Loran-C

overlaid

chart

can

be

shifted

when

the

chart

is

printed

and

thus

compensated

to

take

care

of

actual

observed

readings

from

the

field.

One

should

still

be

careful

when

using

Latitude/Longitude

numbers

directly

from

a

Loran-C

receiver,

especially

when

near

land

since

this

is

where

significant

error

s

can

occur.

(Note

that

the

charts

don't

even

show

Loran-C

grids

over

inland

areas

because

of

the

extreme

distortions

in

the

lat

tices

over

land.)

Also,

Loran-C

is

not

meant

to

be

used

in

harbors

or

ports

since

these

are

usually

surrounded

by

land

masses.

Well,

enough

theory

for

now.

Let's

get

down

to

how

you

actually

operate

your

new

receiver.

Some

advanced

concepts

and

further

cautions

on

the

use

(and

misuse)

of

the

system

will

be

given

later.

7

8

o

c

Oti

ta

■

o

cti

<D

s

o

+->

c

o

o

o

o

i

O

ta

bc

ta

OPERATIONAL

OVERVIEW

The

LC-90

is

basieally

a

rather

simple

unit

to

operate,

although

at

first

glance

it

may

be

a

lit

tle

intimidating

to

someone

who

has

never

used

a

Loran-C

navigator

before.

However

once

you

get

to

know

what

the

various

abbreviations

mean,

the

simplicity

and

logie

behind

the

layout

and

the

design

will

become

more

apparent.

Examine

the

front

panel.

You

will

note

that

there

is

a

large

LCD

readout

taking

up

most

of

the

left-hand

side

of

the

front

panel,

a

keyboard

on

the

right-hand

side,

and

all

sorts

of

abbreviations

printed

on

the

panel

below

the

display.

These

nine

abbreviated

labels

indieate

the

various

Modes

in

which

the

LC-90

may

be

operated.

In

addition,

there

are

10

seeondary

F

u

n

et

ion

s

which

may

be

called

up

to

do

less-often

used

operations.

These

Functions

are

accessed

by

use

of

the

[Tj

key,

followed

by

a

number

from

|~0~1

to

f~9~l

•

The

keyboard

itself

contains

twenty-three

membrane-sealed

touchpad

keys,

and

is

divided

roughly

into

four

functional

areas,

delineated

by

different

color

schemes.

A

distinctive

"beep"

is

generated

to

confirm

to

the

user

that

something

did

indeed

occur

whenever

he

presses

a

key.

The

functional

groupings

of

the

touchpad

keys

are

as

follows:

POWER

ON/OFF

and

DIMMER

These

three

brown

keys

are

located

at

the

top

right

of

the

keyboard.

When

the

operator

presses

the

[PWR|

key,

the

LC-90

is

activated.

After

several

seconds,

the

display

will

begin

to

show

sorae

activity.

It

is

necessary

to

press

both

the

[PWR|

and

the

[OFF]

keys

simultaneously

in

order

to

turn

off

power

to

the

unit.

This

procedure

is

necessary

to

prevent

unintentional

interruption

of

power

should

the

user

accidentally

hit

the

)PWRj

key.

The

|

DIM

|

key

is

used

to

vary

the

level

of

backli

g

h

ting

of

the

display

and

keyboard

for

nighttime

operation.

There

are

four

l

e

vel

s

of

backli

gh

ting

intensity:

bright,

medium,

dim

and

oif.

Each

time

the

|DIM|

key

is

pressed,

the

level

will

change

in

the

above

sequence.

NUMERIC

KEYS

There

are

eleven

numeric

touchpad

keys,

and

these

are

orange

in

color.

The

keys

[O]through

[9]

are

employed

to

enter

all

numeric

data.

The

|

+

/-1

key

is

a

general

purpose

key

that

is

used

to

change

from

North

to

South

latitude,

or

East

to

West

longitude

when

entering

data

for

Modes

or

Functions

requiring

Latitude/Longitude

data,

and

which

is

also

used

to

change

default

values

for

many

Modes

and

Functions

that

can

be

used

either

automatically

or

manually.

This

key

is

also

used

to

turn

on/off

many

functions.

In

each

Mode

or

Function

where

data

may

be

entered,

leading

zeroes

must

be

specified

(for

ex.,

waypoint

"01"

must

be

entered

fully,

rather

than

as

"1.")

The

LC-90

will

reject

entries

it

cannot

understand

where

leading

zeroes

haven't

been

entered.

Trailing

zeroes

needn't

however

be

entered

ful

ly.

For

example,

a

latitude

entry

of

"37"

degrees

is

just

as

valid

as

the

full

entry

of

"370000"

degrees.

10

9

OPERATING

MODE/FUNCTION

SELECTOR

KEYS

The

four

blue

keys

on

the

lower

left

of

the

keyboard

are

the

Mode

selector

keys.

The

two

arrow

shaped

keys

select

which

one

of

the

nine

Mode

screens

is

in

use.

Pressing

these

keys

causes

the

Mode

indicator

arrow

to

move

sideways

to

align

itself

above

the

labels

for

the

operating

Mode

on

the

panel

beneath

the

LCD

display.

The

readouts

on

the

LCD

itself

will

change

in

accordance

with

the

Mode

selected.

Pressing

the

left

arrow

when

the

mode

indicator

is

located

at

the

left-hand

edge

of

the

panel

will

shift

the

indicator

to

the

far

right-hand

Mode.

Similarly,

when

the

indicator

is

at

the

far

right

end,

the

arrow

will

shift

the

indicator

to

the

far

right-hand

Mode.

The

key

labeled

[#]

is

used

to

select

one

of

the

ten

secondary

Functions.

It

is

first

pressed

followed

by

a

number

from

[O]

to

[9]

to

a

ccces

s

these

secondary

Functions.

Note

that

it

isn

T

t

necessary

to

press

the

|ENT|

key

to

activate

the

Function.

The

LCD

display

will

changed

in

accordance

with

the

secondary

Function

selected

by

the

operator.

The

|

TD

<-»

L/L

|

key

is

used

to

change

position

data

from

Latitude/Longitude

format

to

TD

format

and

vice

versa.

OTHER

KEYS

At

the

top

left

of

th

e

key

board

there

are

four

brown

keys,

the

[E~VT|

,

1

~CLR|

A

and

▼

keys.

fEVTI

stands

for

Event,

and

is

used

when

a

position

is

to

be

stored

in

the

Event

Memory

or

Waypoint

Memory,

or

when

an

external

plotter

or

printer

is

connected

to

the

LC-90.

The

position

at

the

moment

this

key

is

pressed

is

sent

out

to

the

external

instrument.

The

brown

[CLR|

key

stands

for

Clear.

It

is

used

to

clear

a

number

from

the

display

or

to

silence

the

audible

alarm.

The

two

arrow

shaped

keys

A

and

▼

are

used

to

select

where

the

data

entry

cursor

will

be

located

on

one

of

the

five

lines

on

the

display.

The

cursor

will

be

indicated

by

the

flashing

of

the

far

left

character

on

the

d

esired

line.

Before

typing

in

the

new

data,

the

operator

pres

s

e

s

th

e

fCLRl

key

to

clear

the

line,

and

af

ter

entering

new

data,

the

blue

[ÉNT|

key

(standing

for

Enter)

will

be

pressed.

The

cursor

will

automatically

advance

to

the

next

line

where

data

may

be

entered

after

the

|

ENTj

key

is

pressed.

Note

that

if

you

acciden

t

ally

type

in

the

wrong

data

or

if

you

hit

the

wrong

key,

you

may

hit

the

[CLR|

key,

followed

by

|ENT

1

to

retrieve

the

data

stored

previously.

The

following

list

shows

a

summary

of

the

primary

operating

Modes,

and

the

secondary

Functions

of

which

the

LC-90

is

eapable

of

showing.

SUMMARY

OF

MODES

AND

FUNCTIONS

Primary

Modes,

Data

Readouts:

S/C

:

Speed

Made

Good

and

Course

Made

Good,

together

with

present

position

(in

L/L

or

TD's,

at

the

discretion

of

the

operator)

and

the

Route

and/or

Way

points

in

use.

11

VTP

:

Velocity

To

Destination

(in

knots)

and

Time

to

Go

(in

Hours

and

Minutes),

again

together

with

present

position

and

Route

and/or

Waypoints

in

use.

R/B

:

Range

(in

nautical

miles)

and

Bearing

(in

degrees

Magnetic

or

True,

at

the

operator's

discretion)

from

present

position

to

destination

waypoint,

again

together

with

present

position

and

Route

and

/or

Waypoints

in

use.

XTE:

Cross-Track

Error

(in

nautical

miles

off

the

desired

track),

with

arrow

indicators

to

show

direction

of

offset

and

direction

to

steer

to

get

back

an

track.

As

usual,

present

position

and

Route

and/or

Waypoints

in

use

are

shown.

Course

offset

in

degrees

and

Range

to

destination

waypoint

are

display

ed

as

well.

Primary

Modes,

Data

Entry:

NAV

:

This

is

the

Navigation

Mode.

The

desired

Route

and/or

Waypoint

(s)

desired

are

selected

in

this

Mode.

Cross-Track

Error

with

Course

offset

and

Range

and

Bearing

to

the

desired

waypoint

are

also

displayed.

PLN

:

This

is

the

Route

Planning

Mode.

The

waypoints

involved

in

up

to

ten

different

Route

Plans

are

selected

in

this

mode.

WPT

;

This

Mode

is

used

to

enter

position

data

into

a

Waypoint.

Waypoint

data

may

be

entered

or

recalled

for

confirmation

either

as

L/L

or

as

TD's.

CUC

:

This

is

the

Calculation

Mode.

Trial

rho-rho

calculations

of

Range

and

Bearing

from

waypoint

to

waypoint

may

be

done

here.

It

is

also

possible

to

Define

a

waypoint

by

Range

and

Bearing

from

present

position

in

this

Mode.

ALM:

This

is

the

Mode

where

Alarm

limits

are

defined

for

the

Cross-Track

Error

alarm,

the

Border

alarm,

the

Arrival

alarm

and

the

Anchor

Watch

alarm.

Secondary

(#)

Functipn:

In

each

of

these

function

the

blue

QO

key

is

pressed,

followed

by

a

single

number.

To

leave

a

secondary

Function,

hit

either

the

left

or

right

arrow

keys.

#0

=

This

is

the

Event

Memory

Function,

where

the

operator

can

display

the

contents

of

each

event

memory.

#J_:

This

is

the

Initialization

Function.

The

user

enters

the

approximate

present

position,

and

if

he

chooses

to

Disable

automatic

selection,

the

GRI

and

the

slave

secondaries

for

use

by

the

LC-90.

#2

:

This

is

the

Position

Offset

Function.

The

operator

may

enter

the

amount

of

delta

L/L

or

delta

TD

offsets

desired

for

a

particular

area.

There

are

nine

"pages"

of

offset

information

that

may

be

stored

in

memory.

#3

:

This

is

the

Averaging

Time

Function.

The

operator

may

choose

the

amount

of

smoothing

time

constant

to

be

appiied

to

the

L/L

and

speed

display.

The

type

of

output

data

available

at

the

rear

panel

for

external

devices

such

as

plotters

or

printers

is

specified

in

this

Function

as

well.

12

#4:

This

is

the

automatic

ASF

(Additional

Secondary

Factor)

and

automatic

Magnetic

Variation

Function.

Both

Functions

may

be

disabled

rnanually.

The

amount

of

ASF

correction

automatically

used

by

the

LC-90

in

the

present

geographic

area

is

displayed.

Note

that

at

0

degrees

variation.

True

North

referenced

bearings

will

be

obtained.

#5:

This

is

the

Cycle

Selection

Function.

The

amount

that

the

tracking

point

is

ti

be

slewed

manually

is

entered

in

this

Function.

#6:

In

this

function

the

SNR

(Signal

to

Noise

Ratio)

and

ECD

(Envelope

to

Cycle

Difference)

are

displayed.

These

numbers

give

the

operator

an

indication

of

the

quality

of

the

incoming

Loran

signals.

The

display

shows

which

cycle

of

the

Master

and

two

secondary

stations

the

LC-90

is

presently

tracking,

and

shows

in

addition,

the

deviation

of

the

internal

reference

oscillator

from

the

ideal

frequency.

#7:

This

Function

is

the

SNR

Visual/Audio

Indicator.

It

allows

the

operator

to

make

trial

adjustments

for

example

of

the

antenna

location

while

watching

the

display

or

listening

to

the

LC-90

buzzer

remotely.

The

tracking

point

for

the

master

and

the

two

secondaries

is

also

displayed,

as

well

as

the

numerical

SNR

value

for

each

station.

#8:

This

is

the

Tuning

Indicator

Function.

The

operator

may

display

the

level

of

signals,

both

interfering

and

desired,

from

70

to

130

KHz.

#9

:

This

is

the

Notch

Filter

status

Function,

where

the

frequency

of

each

automatic

notch

filter

may

be

displayed,

and

if

desired

where

each

of

the

six

filters

may

be

set

manually

on

desired

frequencies.

The

level

of

signal

on

the

frequency

of

each

filter

is

displayed

as

well.

o

D

å

o.

o

.

Si

be

X

>

■

£

13

14

Fig.

4

Typieal

Mode

Screens

INSTALLATION

As

was

pointed

out

in

the

Introduction

to

this

manual,

this

machine

can

only

do

its

intended

functions

if

it

is

installed

properly.

GENERAL

MOUNTING

CONSIDERATIONS

The

LC-90

consists

of

two

units:

the

Display

Unit

and

the

Antenna

Coupler

Unit.

The

Antenna

Coupler

has

been

designed

to

withstand

all

the

rigors

of

the

marine

environment,

and

if

installed

properly,

is

thoroughly

water-

proof.

The

Display

Unit

is

carefully

constructed

to

be

able

to

withstand

the

humidity

and

corrosive

atmosphere

common

in

a

pilothouse,

but

it

is

not

designed

to

be

used

outside,

directly

exposed

to

the

environment!

Salt

water

spray

(or

even

coffee

spilis)

will

most

assuredly

cause

damage

to

the

sensitive

components

inside.

Keep

these

factors

in

mind

when

planning

the

installation

of

the

Display

Unit.

Many

owners

will

undoubtedly

use

the

LC-90

on

small

boats,

many

with

center

corisoles.

The

Display

Unit

must

be

mounted

inside

an

enclosed

cabinet,

completely

shielded

from

salt

water

spray,

and

from

fresh

water

spray

if

the

boat

is

usually

hosed

down

after

a

day's

outing.

Corrosion

can

occur,

especially

on

the

rear

connectors

exposed

to

salt

spray,

unless

these

are

taped

and

thoroughly

sealed

with

putty

compounds

made

especially

for

this

purpose.

Most

small

center

console

boats

are

equipped

with

such

an

enclosed

cabinet

behind

the

wheel,

and

most

have

clear

doors

so

that

equipment

may

be

seen

behind

them.

FURUNO

WILL

ASSUME

NO

RESPONSIBILITY

FOR

CORROSION

DAMAGE

CAUSED

BY

EXPOSURE

TO

EITHER

FRESH

OR

SALT

WATER

SPRAY!

The

LC-90

consumes

very

little

power,

so

there

is

no

need

for

forced

air

ventilation.

However

it

is

necessary

to

provide

at

least

some

space

behind

and

around

the

Display

Unit

to

allow

some

circulation

of

cooling

air

and

to

provide

convenient

access

to

the

rear

connectors.

If

the

Display

is

mounted

in

the

center

cabinet

of

a

center

console

type

of

boat

usually

there

is

sufficient

air

movement

to

cool

the

unit

properly.

Even

though

the

LCD

(Liquid

Crystal)

readout

displays

are

quite

le

gible

even

in

bright

sunlight,

it

is

a

good

idea

to

keep

the

Display

Unit

out

of

direct

sunlight

or

at

least

shaded

because

of

heat

that

can

build

up

inside

the

cabinet.

It

is

a

regrettable

faet

of

modern

life

that

small

attractive

electronic

gear

seems

to

attract

undue

attention

from

thieves.

In

your

installation

planning

it

is

a

good

idea

to

provide

means

either

to

hide

the

gear

when

you

are

not

aboard

or

take

the

gear

off

the

boat

completely

when

you

are

finished

for

the

day.

Consideration

should

be

made

to

provide

space

for

access

to

the

mounting

hardware

on

the

side

and

to

the

connectors

behind

the

Display

Unit.

16

15

DETAILED

INSTALLATION

INSTKUCTIONS

Antenna

Coupler

Unit

Installation:

The

antenna

coupler

unit

is

completely

watertight

when

installed

correctly.

It

should

be

mounted

as

high

as

possible

on

the

boat,

free

from

the

influences

of

nearby

antennas,

rigging,

and

masts.

Since

it

is

rarely

possible

to

avoid

nearby

metallic

objects,

especially

on

small

boats,

a

compromise

must

be

struck

on

most

boats.

Most

skippers

prefer

to

have

their

VI1F

antenna

on

the

highest

mast

because

this

is

their

primary

means

to

signal

a

distress

situation.

The

second

most

eritical

piece

of

eleetronics

on

the

boat

however

should

be

the

Loran-C

antenna,

and

if

this

must

be

on

the

same

mast

as

the

VHP

antenna,

at

least

try

to

mount

it

on

a

crosstree

on

the

other

side

of

the

mast

from

the

VHF

antenna.

A

separation

between

antennas

of

at

least

3

feet

is

needed.

Loran-C

antennas

can

perform

adequately

on

sailboats

with

transom

installations,

but

in

marginal

signal

areas

the

performance

may

not

be

satisfactory.

The

presence

of

stays

and

other

metallic

rigging

can

cause

the

reception

pattern

to

be

somewhat

more

favorable

in

certain

directions,

instead

of

being

omnidirectional

like

it

should

be.

Obviously,

it

is

a

real

nuisance

to

have

to

point

the

boat

in

a

particular

direction

in

order

to

find

out

where

you

are!

There

are

many

sailboat

installations

where

an

insulated

stay

works

adequately

but

a

separate

whip

antenna

up

in

the

clear

is

still

preferable.

The

Antenna

Coupler

uses

a

standard

96

inch

fiberglass

marine

"CB"

whip,

which

is

screwed

into

the

top

fitting.

(NOTE:

so-called

"loaded"

whips

which

are

much

shorter

than

96

inches

are

not

suitable

as

a

whip

for

the

LC-90.)

The

body

of

the

Antenna

Coupler

can

be

mounted

in

two

ways:

1.

The

bottom

of

the

coupler

is

designed

to

accept

a

threaded

extension

mast

(recommended

height

no

longer

than

about

5

feet

to

prevent

undue

flexing

of

the

mast

in

heavy

winds).

The

thread

should

be

1

inch

diameter,

with

a

pitch

of

14

threads

per

inch.

2.

The

side

of

the

coupler

has

a

molded

channel

so

that

it

may

be

mounted

directly

to

a

stub

mast

with

the

two

stainless

Steel

hose

damps.

See

the

drawing

below.

I!

2.5mm

(96

inch)

Jj,

ANTENNA

PIPE£ø26.2mm)

WHITWORTH

FINE

THREAD

CW25-J4)

Antenna

siting

is

not

all

science,

but

neither

is

it

all

"black

magic"

either.

To

determine

the

best

location

on

your

own

boat

it

is

suggested

that

you

temporarily

mount

the

antenna

in

a

likely

location

and

try

it

out.

Later

in

this

section

the

recommended

test

method

will

be

given

to

determine

if

the

installation

site

is

OK.

The

Antenna

Coupler

Unit

comes

with

the

interconnecting

cable

already

prewired

into

it

from

the

factory.

You

may

however

find

it

necessary

to

deal

with

the

display

end

of

the

cable

since

the

connector

is

supplied

already

wired

to

the

display

end.

The

connector

may

not

fit

through

holes

and

wireways,

and

it

may

have

to

be

removed

and

reinstalled

later

af

ter

the

antenna

cable

has

been

routed

through

the

boat.

When

a

4m

whip

antenna

(option-used

in

fringe

reception

areas)

is

used,

its

installation

should

be

as

in

the

drawing

below.

Note

that

the

coupler

is

not

designed

to

withstand

the

strain

of

such

a

large

whip

directly.

Instead,

a

mounting

plate

for

the

4m

whip

must

be

provided,

with

a

wire

to

the

antenna

coupler

from

the

bottom

of

the

whip.

Fig.

8

17

18

i

Display

Unit

Installation:

Locate

the

Display

Unit

in

a

position

where

it

can

be

viewed

and

operated

conveniently

but

where

there

is

no

danger

of

salt

or

fresh

water

spray

or

immersion.

The

Display

Unit

is

mounted

in

a

trunnion

mount.

The

mount

itself

can

be

installed

either

over

head,

on

a

bulkhead,

or

on

a

tabletop.

The

drawing

below

gives

the

recommended

clearances

and

the

mounting

dimensions

for

this

unit.

You

can

use

the

mount

itself

as

a

template

for

locating

the

mounting

bolt

holes.

As

was

stated

before,

make

sure

you

allow

enough

clearance

both

to

get

to

the

connectors

behind

the

unit

and

to

allow

you

to

get

your

hånds

in

on

both

sides

to

loosen

or

tighten

the

mounting

knobs.

Make

sure

you

leave

at

least

a

foot

or

so

of

"service

loop"

of

cables

behind

the

unit

so

that

it

can

be

pulled

forward

for

servicing

or

easy

removal

of

the

connectors.

If

you

find

it

necessary

to

remove

the

antenna

connector

that

goes

to

the

display,

follow

the

directions

in

the

drawing

below.

If

you

don't

know

how

to

sold

er

or

if

you

don't

know

how

to

do

it

well,

it's

best

you

leave

this

part

to

a

competent

service

technician.

In

perhaps

50

percent

of

installation

problems,

poor

soldering

or

wrong

wiring

of

the

connectors

is

where

the

problem

lies.

DO

NOT

SHORT

ANTENNA

CABLE!

Cut

end

ot

cable

even.

Bare

17mm(0.67'')

of

center

Screw

the

pi

ug

assembly

on

Remove

vinyl

jacket

34mm

conductor-don’t

nick

conduc-

cable.

Solder

pi

ug

assembly

<1.34")-don

1

t

nick

braid.

tor.

Trim

bralded

shield

15mm

to

braid

through

solder

(0.6")

and

tin.

Silde

holes.

Solder

conductor

to

coupllng

ring

on

cable.

contact

sleeve.

Fig.

10

Unless

you

are

also

installing

optional

peripheral

equipment

(such

as

a

Track

Plotter,

autopilot

or

a

Printer),

the

only

wiring

necessary

is

for

the

power

connection

and

the

antenna

cable.

19

Power

Connection:

Ship's

power

lines

are

notorious

for

being

"dirty"

electrically.

The

voltage

can

go

all

over

the

place

as

various

heavy

loads

are

placed

on

the

line,

and

the

power

wiring

is

a

prime

source

for

interfering

electrical

signals

(from

such

sources

as

alternators

or

generators,

and

other

electronics

equipment,

like

radars

or

echosounders.)

The

LC-90

is

a

very

forgiving

machine

since

it

has

a

built-in

universal

D.C.

power

supply

that

can

take

input

voltages

from

10

to

42

V.D.C.

Iiowever,

a

piece

of

gear

of

this

quality

deserves

to

have

a

Circuit

breaker

dedicated

to

it

alone.

The

size

of

the

wire

feeding

power

to

the

unit

should

be

no

less

than

AWG

16

gauge

(0.75mm

square).

Ground

Connection:

No

less

important

for

proper

operation

is

the

ground

for

the

Display

Unit.

On

a

steel

boat,

a

good

connection

to

the

hull

is

sufficient.

On

a

wood

or

fiberglass

boat,

it

is

best

to

use

a

ground

plate

mounted

on

the

hull

exterior;

if

this

is

not

practical

the

engine

block

can

be

used.

Do

not

"share"

ground

leads

that

go

to

other

equipment

in

the

console,

but

instead

run

a

separate

heavy-duty

wire

for

the

LC-90

alone.

Follow

the

drawing

below

for

detailed

wiring

information.

TESTING

AFTER

INITIAL

INSTALLATION:

The

best

way

to

check

for

the

adequacy

of

an

installation,

and

for

the

presence

of

noise

aboard

the

boat

which

might

hamper

Loran-C

reception.

20

is

to

use

the

"SNR”

(Signal

to

Noise

Ratio)

function

in

the

LC-90

itself.

Make

sure

all

electrical

and

electronic

machinery

on

your

boat

is

turned

off

before

starting

this

test.

This

includes

the

en

gine

and

any

auxiliaries

as

well.

Before

plugging

the

power

connector

in

to

the

back

of

the

LC-90,

recheck

the

polarity

of

the

DC

using

a

voltmeter.

Then

plug

the

power

connector

into

the

back

of

the

unit.

Don't

worry

in

the

following

procedure

that

you

might

not

understand

exactly

what

is

going

on:

the

details

will

be

explained

later

in

this

manual.

For

now

you

just

want

to

be

sure

that

the

installation

is

good

enough

and

free

enough

from

external

interference

so

that

you

can

run

the

LC-90

through

its

paces,

and

learn

how

to

use

it

later.

1.

T

u

r

n

on

the

LC-90

by

pressing

the

|PWR|

key

while

simultaneously

holding

down

the

’CLRl

key.

This

will

clear

the

internal

memory

completely,

and

will

allow

th

e

unit

to

initialize

itself

for

your

geographic

area.

Continue

to

hold

the

ICLR1

key

until

two

distinctive

beeps

of

the

buzzer

are

heard.

The

LC-90

will

then

automatically

go

into

its

Initialization

function

#1,

and

will

be

ready

to

accept

the

approximate

Latitude

of

your

present

position.

You

must

know

and

enter

your

latitude

within

a

tolerance

of

one

degree

from

the

true

position.

For

the

sake

of

illustration,

assume

for

now

that

you

are

located

near

San

Franciseo,

and

that

your

present

position

is

approximately

37

degrees

North

latitude,

and

122

degrees

West

longitude.

Enter

the

following

keystrokes:

fCLRl

|~3~1

|~7~|

|

ENT

S

Ente

ring

initial

Latitude,

Function

#1

The

flashing

cursor

will

automatically

advance

to

the

longitude

line,

and

here

you

would

enter:

|

CLR|

iT|

1~2~1

j~2~|

|

HNT

j

Entering

initial

Longitude,

Function

#1

Note:

If

your

present

location

is

in

the

Southern

latitudes

or

the

Eastern

longitudes,

you

will

need

to

override

the

default

North

and

West

hemispheric

values

by

pressing

the

I

+/-

I

key.

The

cursor

will

automatically

place

itself

on

the

next

line,

and

the

”A”

on

that

line

will

flash.

For

now

we

will

use

the

automatic

GRI

and

slave

selection

function.

Wait

for

less

than

approximately

120

seconds

to

see

what

the

LC-90

decides

as

appropriate

values.

In

our

San

Francisco

example,

the

unit

would

automatically

come

up

with

a

GRI

of

9940,

and

with

slave

selections

of

27

and

43.

You

needn't

worry

about

what

these

numbers

mean,

at

this

point.

Simply

go

on

and

leave

Function

#1

by

hitting

either

the

left

or

right

arrow

cursor

key

s.

Now

press

the

left

or

right

arrow

cursor

key

until

the

indicator

lines

up

over

the

"S/C”

label.

You

should

see

displayed

a

screen

similar

to

the’

one

shown

below.

Fig.

12

S/C

Mode

Screen

ASF

MAG

V

3138.00’u

13333

.

3

%

0

IvH

O

ru

*_

p

n

c

L

U.3

n

o

3

u

u

3

s/c

2.

Y

o

u

may

wish

to

watch

the

receiver

go

through

its

acquisition

sequence

by

hitting

the

|TD

*-*

L/L

|

conversion

key.

You

can

now

watch

as

the

unit

setties

down

on

the

correct

TD

values

for

your

area.

While

the

LC-90

is

busy

first

identifying

the

master

and

slave

signals,

it

will

flash

the

MCYC,

MSNR,

SNR

and

CYC

warning

indicators.

While

it

is

acquiring

and

locking

onto

the

signals,

these

warning

indicators

will

stop

flashing.

When

acquisition

is

complete

(in

about

3

to

5

minutes,

depending

on

the

quality

of

the

Loran

signals

in

your

area)

all

signal

warning

indicators

will

extinguish,

and

the

TD

readout

will

be

stable,

with

perhaps

only

the

least

significant

digit

to

the

right

of

the

decimal

point

changing

randomly

up

and

down

a

small

amount.

Now

call

up

the

SNR

function,

the

#6

Function,

by

first

pressing

the

[Tj

key

and

then

the

ti]

key.

You

should

see

a

screen

similar

to

the

one

below.

MCYC

MSNR

BO

10

-

13

0

CYC

f~

SNR

'“J

f-i

/“*

BLK-J

1

*

*

EC

d

n

o

u

J

i

n

c

tuu

p

c

C

3

n

u

5

SI

n

o

t

u

i

5

52

Fig.

13

Function

#6

Screen

The

SNR

for

the

Master

and

the

two

slave

secondary

stations

automatically

selected

by

the

receiver

are

displayed

on

the

‘left-hånd

side

of

the

third,

fourth

and

fifth

lines

respectively.

The

maximum

value

for

SNR

is

"99,”

and

unless

you

happen

to

be

in

a

very

strong

signal

area,

it

is

likely

that

at

least

one

of

the

stations

being

received

will

have

an

SNR

value

less

than

99.

It

is

important

that

you

have

at

least

one

station

whose

SNR

is

less

than

99

so

that

you

can

easily

observe

any

small

degradation

of

SNR

as

various

interference

sources

on

your

boat

are

investigated

one

by

one.

If

at

least

one

station

exhibits

an

SNR

lower

than

99,

you

may

proceed

to

step

4.

below.

-Before

doing

that

however,

write

down

the

SNR

values

for

the

three

stations,

preferably

in

the

back

of

this

book

so

that

you

will

have

a

permanent

record

of

SNR

values.

Otherwise,

go

to

step

3.

below

first.

3.

I

n

the

extremely

unlikely

situation

where

all

three

stations

have

S

NR's

of

99,

go

back

to

function

#1

by

pressing

the

[Tj

key

followed

by

the

Q]

key.

Look

in

the

appendix

at

the

back

of

this

book

for

the

chart

that

describes

your

geographic

area.

You

will

note

that

any

particular

area

has

two

slave

secondaries

associated

with

it

that

are

the

optimum

choices.

However,

most

Loran

chains

have

other

secondary

stations

available

that

do

not

represent

optimum

choices,

usually

because

they

are

far

removed

from

that

area,

and

thus

would

be

rather

weak

in

signal

strength.

In

the

case

of

our

San

Francisco

example,

the

optimum

slave

secondaries

are

the

"27”

and

the

”43”

secondaries.

However

there

is

a

third

secondary

station

in

the

chain:

the

"11”

station,

and

it

is

located

in

Washington

state,

far

from

the

San

Francisco

area

and

hence

probably

rather

weak.

Again,

you

shouldn't

worry

at

this

point

that

you

may

not

know

exactly

what

these

mysterious

numbers

mean,

just

note

the

two-digit

value

of

the

other

secondary

stations

that

the

Loran

chain

is

capable

of

providing

in

your

own

area

of

operation.

22

21

Coing

back

to

our

example,

if

the

Mastor

and

the

two

optimum

secondaries

happened

to

be

exhibiting

SNR's

of

99,

then

we

might

select

the

"11"

station

to

observe

in

order

to

evaluate

subtle

changes

in

SNR.

readings

due

to

interference

from

other

sources

on

the

boat.

Make

sure

you

are

in

Function

#1.

Move

down

to

the

third

line,

usinu

the

dow

n

arro

w

▼

cursor.

Hit

ICLRl

,

and

then

hit

the

key,

followed

by

HÉNT|

to

change

the

"A"

to

"d,"

disabling

the

Automatic

Selection

process.

Move

the

cu

r

s

o

r

with

the

▼

down

arrow

down

to

the

fourth

line,

hit

[CLR|

[TI

|T]

I

ENT|

.

Now

go

back

to

function

#6,

by

hitting

the

GO

key

and

then

the

00

key.

Observe

the

SNR

of

the

weakest

station,

and

write

the

numbers

for

all

three

stations

down

in

the

back

of

this

manual.

Now

you

can

proceed

to

step

4

below.

4.

Now,

turn

on

the

other

electronics

on

the

boat

(radar,

echosounder,

etc.)

one

at

a

time

and

observe

the

SNR

readings

over

a

period

of

several

minutes.

Make

sure

you

operate

the

other

equipment

in

all

possible

modes.

For

example,

make

sure

that

the

radar

is

used

in

both

standby

and

then

transmit

modes,

with

the

scanner

turning

and

turned

off,

etc.

Write

down

the

resulting

SNR's

for

each

piece

of

gear,

and

then

shut

it

off

and

do

the

next

piece

of

equipment.

If

the

SNR

reading

drops

from,

say,

90

to

85,

then

you

are

probably

OK,

but

if

it

drops

from

90

to

60

or

lower,

you

have

a

definite

interference

problem

that

a

qualified

electronics

technician

is

going

to

have

to

fix

before

you

can

obtain

proper

Loran-C

performance.

Your

written

record

of

SNR

values

will

be

helpful

to

him.

If

yod

are

quite

fortunate

you

will

find

that

no

other

piece

of

electronics

on

board

your

boat

interferes

badly

with

your

new

Loran-C.

Assuming

that

your

luck

is

with

you

and

that

this

is

indeed

the

case,

let's

go

on

to

test

a

device

that

in

at

least

90

percent

of

Loran-C

installations

does

cause

an

interference

problem:

the

alternator.

There

are

several

technical

reasons

why

alternators

seem

to

be

aniagonistic

toward

Loran-C

receivers,

but

going

into

the

why's

and

wherefore's

isn't

as

iniportant

as

figuring

out

how

to

cure

the

little

beast

of

this

nasty

habit.

Start

your

engine

and

increase

engine

speed

un

til

your

charging

ammeter

goes

upscale.

You

will

probably

now

notice

that

the

SNR

indication

of

your

Loran-C

begins

to

plummet.

Not

all

alternators

respond

to

interference-removal

techniques

in

the

same

manner.

Some

alternators,

it

is

sad

to

say,

cannot

be

suppressed

at

all,

and

these

must

be

replaced

or

rebuilt

if

you

wish

to

have

useable

Loran-C

operation.

Don't

blame

the

Loran-C

receiver!

It

is

a

sensitive

instrument,

and

it

is

simply

responding

to

the

noise

broadcast

by

the

alternator.

The

first

step

to

take

when

alternator

noise

is

discovered

is

to

try

a

large

electrolytic

capacitor

mounted

right

at

the

output

terminals

of

the

alternator.

The

capacitor

must

be

rated

for

the

nominal

output

voltage

of

the

alternator,

plus

a

50%

safety

factor.

For

example,

if

the

alternator

is

a

nominal

32

V.D.C.

unit,

you

should

use

a

capacitor

rated

for

no

less

than

32

+

32/2,

or

48

Volts.

A

50

V.D.C.

unit

should

suffice.

of

the

capacitor

is

connected

with

a

short

lead

(less

than

4

inches

long)

to

the

Output

terminal

of

the

alternator,

using

a

large

crimp

lug

to

go

under

the

terminal,

in

parallel

with

the

heavy

lead

going

to

the

battery

bank.

The

negative

terminal

of

the

capacitor

should

go

to

a

mounting

bolt

used

to

secure

the

alternator

to

its

mounting

frame.

This

lead

also

must

be

kept

shorter

than

4

inches

or

so

in

order

for

the

capacitor

to

do

its

job.

Do

Not

connect

the

capacitor

to

the

Field

terminal

of

the

alternator,

at

the

risk

of

destroying

the

alternator

itself.

Hopefully,

the

electrolytic

capacitor

will

do

the

job

for

you,

and

if

that

is

the

case

you

can

proceed

to

mount

it

securely

to

the

alternator,

perhaps

by

using

"tie-wraps".

Make

sure

the

capacitor

isn't

able

to

move

around

under

vibration,

since

the

leads

could

be

broken

off.

If

you

have

any

doubts

about

what

you

are

doing,

it

is

time

to

call

in

a

qualified

electronics

technician,

especially

if

the

simple

capacitor

treatment

doesn't

do

the

trick.

Color

TV

1

s

:

One

other

particularly

nasty

interference

source

is

the

typical

home-grade

color

television,

although

sometimes

a

regular

black

and

white

TV

will

wreak

havoc

on

Loran-C

reception.

Unfortunately,

the

only

solution

to

this

sort

of

interference

is

to

turn

the

offending

TV

off,

or

else

purchase

a

commercial

grade

TV

receiver

which

is

better

shielded

than

the

home-quality

units.

HOW

TO

COMBINE

WITH

AUXILIARY

EQUIPMENT

The

LC-90

provides

a

data

output

connector

on

the

back

panel.

This

is

used

for

connection

to

peripheral

equipment,

such

as

a

position

plotter,

a

printer,

or

an

autopilot.

Position

data

is

sent

outside

the

LC-90

in

one

of

several

different

data

formats:

a.

Furuno

CIF

(Computer

InterFace)

for

Furuno

peripherals.

b.

NMEA

0183

Complex

Format,

for

plotters.

c.

NMEA

0180

Simple

Format,

for

Autopilots.

An

optional

connector

cable

kit

(LC-1091

—

Furuno

Code

No.

000-041-156)

is

needed

to

access

the

output

data.

The

interconnection

diagram

is

shown

on

the

next

page.

This

capacitor

should

be

a

"computer-grade"

unit,

that

has

internal

vents

in

case

it

should

overheat

and

possibly

explode,

and

the

capacity

of

the

electrolytic

capacitor

should

be

about

10,000

microfarads

or

so.

Be

careful

to

observe

the

polarity

of

the

capacitor.

Reverse

polarity

will

destroy

the

capacitor,

and

could

damage

the

charging

system

as

well.

The

positive

lead

23

24

BASIC

LEVEL

OPERATIONS

*6

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*

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CABLE

CO-SPEVV-SB-C

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CONNECTOR

CLAMP.

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OOND

THRU

CABLE

CLAMP.

*

6

LEAD

WIRES

PITTED.

SOLDER

IN

FIELD.

CUT

UNUSED

WIRES.

*7

LOP’S

LINES

NOT

PLOTTED.

*

S.

CONNECTORS

NOT

SUPPUED

AS

STANDARD.

*9

LOP'S

&

L/L

PLOTTED.

Fig.

14

INTERCONNECTING

DIAGRAM

FOR

LORAN-C

NAVIGATOR

LC-90

—

PERIPHERAL

EQUIPMENT

TURNING

THE

UNIT

ON

AND

OFF

Press

the

|PWR|

key.

After

several

seconds

(during

which

time

the

LC-90

will

be

performing

an

internal

self-check)

the

display

will

activate.

If

an

error

should

be

detected

during

the

self-check

sequence,

an

error

message

will

be

displayed

on

the

screen.

Details

for

the

meanings

for

these

error

messages

are

described

in

the

Troubleshooting

Section.

To

turn

the

LC-90

off

you

must

press

both

the

[TWR|

and

j

OFF

I

keys

simultaneously.

This

specific

sequence

is

necessary

in

order

to

preven

t

you

from

inadvertently

turning

off

the

unit

by

accidently

pressing

the

1

P\VRI

key.

If

this

were

to

happen

you

would

have

to

wait

another

five

rninutes

or

so

after

power

is

turned

on

again

while

the

unit

acquires

and

locks

onto

the

signals.

INITIALIZING

THE

NAVIGATOR

FOR

YOUR

OWN

GEOGRAPHICAL

AREA

The

LC-90

is

designed

to

retain

in

memory

all

information

necessary

for

operation

whether

it

is

turned

on

or

off.

An

internal

"keep-alive"

battery

performs

this

function.

Once

the

LC-90

has

been

initialized

for

your

area,

you

need

do

nothing

more

than

turn

the

power

back

on

when

you

want

to

set

out

on

a

new

voyage.

As

"smart"

a

unit

as

the

LC-90

is,

it

still

needs

to

know

approximately

where

it

is

located

in

order

for

it

to

home

in

on

the

correct

Loran

signals

for

that

area.

Thus

the

first

time

you

use

the

unit

you

must

initialize

it

for

your

geographic

area.

From

then

on,

unless

you

wish

to

override

its

automatic

selections,

the

unit

will

determine

the

exact

position

automatically.

You

must

enter

your

approximate

location

within

about

+/-

3

degrees,

although

you

may

have

to

be

more

accurate

than

that

if

you

are

located

in

an

area

close

to

a

baseline

extension.

In

this

case

the

unit

requires

a

starting

location

within

about

1

degree

of

the

actual

location,

Similarly,

if

you

move

the

LC-9G

more

than

about

6(1

miles

(approximately

1

degree

in

latitude)

with

the

power

off

you

wili

need

to

reestablish

the

approximate

starting

position.

Before

you

start

operation,

obtain

a

Navigation

Chart

for

your

area,

preferably

one

with

Loran-C

TD

lines

overprinted

on

it.

Keep

this

chart

nearby

as

you

go

through

the

various

procedures

so

that

you

can

verify

that

the

LC-90

is

giving

you

reliable

and

sensible

numbers.

Clearing

the

Memory

:

The

very

first

time

you

turn

on

your

new

unit,

you

will

have

to

clear

the

internal

memory

to

ensure

that

no

stray

data

has

been

stored

there.

Make

very

sure

that

you

want

to

clear

the

memory

completely

before

you

do

this:

all

information,

including

waypoints

that

you

may

want

to

keep,

will

be

lost

after

this

operation!

Make

sure

the

LC-90

is

tu

r

n

e

d

off

first,

and

t

hen

h

old

down

the

1CLR

|

touchpad

while

pressing

the

[PWR

|

key.

Hold

the

rCLRj

key

down

un

til

you

hear

two

beeps,

and

then

you

may

release

it.

Initializing

Latitude/Longitude

(Function

#1):

After

the

memory

has

been

cieared

(or

after

you

call

up

Function

#1),

you

will

find

the

cursor

on

the

latitude

line.

After

clearing

memory

you

will

find

25

26

that

the

line

is

full

of

dashes.

(After

hitting

the

|

CLH

j

button

after

calling

up

Function

#1

you

will

find

the

line

full

of

dashes.)

Enter

your

approximate

latitude.

Assume

for

sake

of

illustration

that

you

are

in

San

Francisco,

and

that

the

approximate

location

is

37

degrees

North

latitude

and

122

degrees

West

longitude.

The

sequence

of

keystrokes

to

enter

this

information

would

be:

[CLR|

HH

in

[ÉNTj

37°00.00'

N

Latitude.

Note

that

the

entry

of

trailing

zeroes

is

optional.

For

example,

you

eould

have

entered

the

full

latitude

of

"370000"

rather

than

the

short-form

"37"

if

you

wanted

to.

The

cursor

will

automatically

move

down

to

the

next

line,

where

you

will

enter

the

longitude.

The

keystrokes

for

this

operation

are:

fCLRl

mmm

[ENTl

122°00.00'

W

Longitude.

Note

that

if

the

longitude

were

for

example,

22

degrees

North,

you

would

have

to

enter

the

leading

zero:

rCLR|

Qf]

\2]

[TI

fÉNTi

022°00.00

t

N

Latitude.

Note

also

that

the

default

values

for

latitude

is

North

latitude

and

West

longitude.

If

you

are

in

the

Southern

latitudes

or

Easterly

longitudes,

you

will

need

to

override

the

default

hemispheric

values

by

using

the

f

+

7-1

key.

For

example,

if

you

are

located

in

Osaka,

Japan,

at

34

degrees

North

latitude

and

135

degrees

East

longitude,

you

would

enter:

fCLRl

HH

l~4l

[ENT|

34°00.00'

N

Latitude.

I

CLR

1

m

i~3~|

f5~|

|+/-

IfENT]

135°00.00'

E

Longitude.

Now

you

should

find

that

the

cursor

has

automatically

moved

to

the

third

line,

and

that

the

"A"

on

that

line

is

flashing.

This

gives

you

the

opportunity

to

Disable

the

"Automatic"

selection

of

GR1

and

the

two

slave

secondaries.

At

this

time

we

suggest

that

you

let

the

LC-90

automatically

s

el

eet

these

values.

In

a

later

section

of

this

manual

you

will

learn

the

procedure

to

Disable

the

automatic

process.

Now

the

LC-90

will

begin

searching

for

the

master

and

slave

stations

to

verify

the

present

approximate

position

you

just

entered.

The

display

will

show

"9999"

for

the

GRI,

and

"99"

for

both

slave

stations.

The

"MCYC,"

"MSNR,"

"SNR"

and

"CYC"

signal

warning

indicators

will

flash

at

this

time.

After

about

a

minute,

these

warning

indicators

will

cease

flashing,

and

the

appropriate

GRI

and

slave

secondary

TD

numbers

will

appear

on

the

fourth

and

fifth

lines.

A

typical

Function

#1

is

shown

below.

Fig.

15

Function

#1

Screen

27

Note

that

the

secondary

stations

are

represented

by

the

first

two

digits

of

the

appropriate

number

of

microseconds.

You

may

wish

to

look

in

the

Appendix

A

in

the

back

of

this

manual

to

assure

yourself

that

the

unit

has

chosen

the

correct

GRI

and

slaves

for

your

area.

You

should

now

go

back

to

the

S/C

Mode

to

observe

the

receiver

while

it

is

locking

onto

the

Loran

signals.

Press

either

the

◄

or

the

►

left

or

right

arrow

key

to

exit

Function

#1,

and

then

press

either

one

of

these

keys

until

the

Mode

indicator

arrow

is

lined

up

ov

er

the

"S/C

"

label

on

the

front

panel

under

the

display.

Now,

press

the

|TD

l/l]

key

to

watch

the

TD's

change

while

the

unit

is

locking

onto

the

Loran

signals.

After

acquisition

and

locking

is

complete

all

the

signal

warning

indicators

will

be

extinguished,

and

the

TD

readings

will

be

stable.

You

must

always

remember

that

the

unit

is

not

ready

for

navigation

until

these

signal

warning

indicators

are

extinguished.

These

indicators

will

be

fully

explained

in

a

later

section

of

this

manual.

The

acquisition

process

will

take

between

three

and

five

minutes,

depending

on

the

quality

of

the

Loran

signals

in

your

area.

In

areas

of

signal

interference,

posi

tion

data

is

unreliable

for

the

first

20

minutes

because

the

notch

filters

are

seeking

out

offending

signals.

See

page

65

f

or

more

de

tails.

Switch

to

the

Latitude/Longitude

display

by

pressing

the

|TD*-L/L]

key

again.

Note

that

the

L/L

readout

is

stable,

and

that

your

position

is

displayed

in

degrees,

minutes

and

tenths

of

minutes

(not

seconds!).

Check

the

LC-90's

position

with

that

shown

on

your

chart.

It

normally

should

be

reasonably

close,

but

while

you

are

in

port

the

position

may

be

as

far

off

as

a

quarter

mile

or

so

because

of

signal

distortion

caused

by

passage

of

the

signals

over

land

nearby.

Don't

worry:

things

will

get

more

accurate

once

you

are

out

of

harbor.

However,

it

is

still

a

good

idea

to

check

your

TD

numbers

against

those

from

a

nearby

vessel

and

with

your

chart

to

en

sure

that

the

unit

has

locked

onto

the

correct

point

of

the

slaves

and

the

master

signals,

and

that

no

strange

things

have

occurred

during

the

acquisition

process.

It

is

well

to

remember

that

that

the

TD

lattice

printed

on

a

Loran-C

chart

is

adjusted

before

printing

to

compensate

for

warping

of

the

grid

because

of

ASF

(Additional

Secondary

Factors),

and

that

TD's

plotted

on

such

a

chart

are

thus

inherently

more

accurate

than

the

Latitude/Longitude

calculated

from

TD's.

In

other

words,

TD's

are

observed

phenomena,

and

Latitude/Longitude

numbers

are

derived

mathematically

from

this

observed

data.

READING

SPEED

AND

COURSE

(S/C

Mode)

Verify

that

the

Mode

indicator

arrow

is

lined

up

over

the

"S/C"

labelIt

will

take

a

minute

or

two

after

the

receiver

has

finished

its

acquisition

process,

but

you

will

eventually

see

the

display

showing

the

Speed

Made

Good

and

Course

Made

Good.

Of

course,

if

you

are

presently

at

the

dock,

the

speed

should

be

close

to

zero,

and

the

course

will

randomly

vary

around

the

compass

rose.

Note:

this

function

as

well

as

many

others

will

only

work

after

the

receiver

has

completed

the

acquisition

process

and

after

all

warning

indications

have

been

extinguished.

The

Speed

Made

Good

is

defined

as

the

speed

over

ground,

and

is

calibrated

in

knots.

The

Course

Made

Good

is

referenced

to

Magnetic

North

whenever

the

MAGV

label

is

shown

in

the

upper

right-hand

side

of

the

display.

The

28

amount

of

Magnetic

Variation

is

automatically

calculated

by

the

LC-90

for

the

your

geographic

area.

You

may

at

this

time

wish

to

look

at

the

amount

of

magnetic

variation

prese

n

tl

y

being

used.

This

can

be

done

by

accessing

Fu

netion

#4.

Press

the

[S

key,

folio

wed

by

the

Q]

key.

A

ty

pie

al

display

is

shown

in

Fig.16.

The

label

"vAr"

in

the

top

line

of

the

refers

to

"Magnetic

Variation,"

and

the

"A"

shown

refers

to

"Auto,"

indicating

that

the

variation

is

applied

automatically.

ASF

MAG

V

uHr

R

i

?

R

5

F

n

_

u

n

n

n

c

U

LU

-

i

3

C

1

U.D

Fig.

16

Function

#4

Screen

The

preprogramined

magnetic

variation

values

are

the

average

of

those

in

an

area

of

approxiinately

10

degrees

latitude

by

10

degrees

longitude.

Ihe

preprogramined

variation

is

typically

acc

urate

within

plus/minus

3

degrees,

which

is

within

the

limits

of

accuracy

to

which

most

coinpasses

have

been

coinpensated

anyhow.

Ilowever,

if

more

accurate

magnetic

bearings

are

needed,

enter

the

local

variation

manually,

using

the

following

procedure.

Manual

Entry

of

Magnetic

Variation

(Function

#4)

:

1.

Verify

that

the

unit

is

in

Function

#4.

2.

Press

|

CLRl

.

The

"A"

will

change

to

a

dash

next

to

the

label

"VAR"

on

the

top

line.

3.

Press

P7U

and

then

[ENTl

.

You

will

see

the

"A"

change

to

a

"d,"

indicating

that

the

Automatic

mode

has

been

Disabled.

Now

the

unit

has

been

placed

in

manual

magnetic

variation

mode.

The

cursor

will

automatically

advance

to

the

next

line.

4.

Type

in

the

desired

magnetic

variation,

followed

by

[ÉNTi

.

For

example,

if

the

magnetic

variation

for

your

area

is

12

degrees

West,

the

keystroke

sequence

would

be

[CLRl

CD

H]

fENTj

.

If

howe

ver

the

ma

gn

etic

va

r

iatio

n

is

12

degrees

Fast,

then

the

sequence

would

be

|CLR[

\+J-\

LU

|2J

1,

MU

*

since

the

default

(+)

value,

standing

for

West

variation,

must

be

overridden.

The

MAGV

indicator

at

the

top

of

the

display

will

be

on

whenever

Magnetic

bearings

are

in

use.

True

Bearings

(rather

than

Magnetic

Bearings)

(Function

#4)

:

If

you

would

rather

have

the

LC-90

display

bearing

in

True

(relative

to

True

North

rather

than

magnetic

north),

this

can

be

accomplished

by

setting

the

magnetic

variation

in

the

Disable

automatic

mode

to

be

zero

degrees.

Verify

that

the

LC-90

is

in

Function

#4,

and

then

select

the

"d"

mode

using

the

EZ3

key.

Move

the

cursor

down

to

the

second

line

and

type

in

00

for

the

variation.

The

entire

sequence

is:

SETTING

THE

AVERAGING

TIME

(Function

#3)

If

you

are

still

presently

sit

tin

g

at

the

dock

while

you

are

learning

the

operation

of

your

new

Loran-C

navigator,

you

may

note

that

the

speed

reading

varies

a

bit,

in

a

random

fashion.

This

is

a

function

of

several

factors,

most

noteworthy

being

the

strength

of

the

incoming

Loran-C

signals

and

the

minute

random

variations

of

the

propagation

path

between

you

and

the

transmitting

station.

The

calculation

of

speed

is

sensitive

to

these

random

variations,

especially

at

low

speeds.

You

may

smooth

out

excessive

speed

fluctuations

by

specifying

an

"averaging"

time

constant

that

in

essence

lengthens

the

time

interval

over

which

the

calculation

is

done.

The

tradeoff

for

a

less-jittery

speed

readout

is

that

sudden

changes

in

speed

(actual

acceleration

or

deceleration

of

the

boat)

take

longer

to

show

up

on

the

S/C

readout.

Iri

general,

an

Averaging

time

constant

of

1

to

4

is

a

practical

value

for

most

people,

but

you

may

want

to

experiment

some

with

the

value

that

most

suits

you.

It

should

be

noted

that

the

Averaging

time

constant

will

affeet

the

speed

that

the

Latitude/Longitude

readout

changes

as

well

as

the

Speed

readout,

but

that

the

,TD

readout

will

not

be

affeeted.

To

change

the

Averaging

constant

access

Function

#3.

The

amount

presently

used

will

be

shown

on

the

first

line,

to

the

right

of

the

label

"AvE."

To

enter

an

averaging

constant

of

4

you

would

use

the

following

keystroke

sequence:

I

CLRI

[4~|

|ENT|

Entering

Averaging

constant

of

"4."

For

the

time

being

don't

worry

about

the

other

lines

on

the

display.

We'll

g

et

into

those

subjects

later.

AUTOMATIC

ASF

(Function

#4)

You

will

remember

that

in

the

Elementary

Theory

Section

that

we

said

that

the

LC-90

has

a

built-in

capability

of

using

TD

offsets

to

compensate

for

warpage

of

the

TD

grid

occurring

due

to

ASF

(Additional

Secondary

Factors)

caused

by

propagation

of

the

Loran

signals

over

part-land,

part-sea

paths.

This

automatic

ASF

compensation

will

yield

better

accuracy

of

the

calculated

Latitude/Longitude

than

will

the

raw

calculation

using

uncompensated

TD

numbers.

When

the

LC-90

is

first

used

af

ter

the

memory

has

been

cleared,

the

default

setting

for

automatic

ASF

compensation

is

"off."

For

most

operations

using

latitude/Ion

gitude

it

is

desirable

to

have

the

automatic

compensation

engaged

all

the

time.

Only

when

TD

numbers

(perhaps

from

a

fishing

buddy

or

your

own

old

records

from

another

Loran-C

receiver)

are

used

will

it

be

necessary

to

disable

automatic

ASF

compensation.

The

LC-90

contains

a

built-in

table

of

ASF

compensation

values

for

geographic

areas

where

these

warpages

have

been

measured

by

the

U.S.

and

Canadian

Coast

Guards,

but

other

areas

of

the

world

have

not

been

measured

as

of

this

time.

To

activate

the

automatic

ASF

compensation,

you

must

call

up

the

Function

#4

by

first

typing

fil

fol

l

owed

by

[4]

.

As

with

all

the

Functions

it

isn't

necessary

to

use

the

|ENTj

key

after

typing

in

the

PH

*

QD

[4~1

[CLRl

fT/T]

fENTl

[CLRl

[0]

OD

HENT]

True

North

bearings.

The

MAGV

indicator

at

the

top

of

the

display

will

disappear.

You

should

now

see

a

screen

similar

to

the

one

in

Fig.

16,

where

the

cursor

will

be

on

the

"A,"

since

it

is

flashing.

This

is

the

Automatic

Variation

function.

You

will

need

to

hit

the

down

arrow

key

twice,

and

hit

\

CLR

I

29

30

INTERMEDIATE

LEVEL

OPERATIONS

followed

by

I

+/-1

.

You

should

see

the

"OFF"

indication

next

to

the

label

"ASF"

change

to

"On."

If

your

geographic

area

is

one

of

those

that

have

ASF

compensation

values

tabulated

for

it,

af

ter

less

than

about

2

minutes

of

computations,

you

will

see

the

values

of

TD

offsets

that

will

now

automatically

be

factored

into

the

L/L

computations.

If

your

area

doesn't

have

any

ASF

compensation

values

available,

the

"ASF"

indicator

that

has

now

appeared

on

the

top

of

the

display

will

blink.

Otherwise

this

indicator

will

be

steady,

indicating

that

automatic

ASF

compensation

is

in

effect.

Note

that

the

ASF

compensation

values

programmed

into

the

LC-90

are

the

average

values

for

a

1

degree

by

1

degree

grid.

If

for

some

reason

you

need

more

accurate

compensation

values,

you

will

have

to

enter

these

manually.

This

procedure

will

be

covered

in

the

Advanced

Level

Operation

section

later

in

this

manual.

Meanwhile,

go

back

to

any

of

the

Modes

showing

present

position

(Modes

S/C,

VTD,

R/B,

XTE,

WPT,

CL

C

and

ALM)

to

see

your

present

position.

Compare

this

indicated

position

to

that

on

your

chart,

and

you

should

see

that

it

compares

more

closely

than

it

did

before

ASF

compensation

was

applied.

D

IMMER

The

backlighting

illumination

level

for

the

display

and

the

keyboard

may

be

varied

in

four

different

levels

of

intensity:

bright,

medium,

dim

and

off.

Press

the

|

DIM

|

key

four

times

to

change

the

level

in

this

sequence.

SUMMARY

OF

BASIC

OPERATIONS:

If

you

have

faithfully

read

this

far,

you

will

find

that

you

have

mastered

the

basics

necessary

to

use

your

LC-90.

You

now

know

the

following:

•

You

know

how

to

enter

your

approximate

location

in

Latitude/Longitude

for

initialization

of

the

unit.

•

You

know

that

if

you

stay

in

the

same

general

area

after

the

unit

has

once

been

initialized

that

all

you

have

to

do

at

the

start

of

a

new

day

is

turn

the

power

on

to

the

LC-90.

•

You

know

how

to

read

your

position

in

both

L/L

and

TD's.

•

You

know

how

to

reduce

jittery

speed

or

L/L

readings

with

the

Averaging

function.

•

You

know

how

to

apply

automatic

ASF

compensation

for

more

accurate

L/L

computations.

•

You

know

how

to

adjust

the

level

of

illumination

of

the

readout

and

the

keyboard.

In

faet,

you

know

quite

a

bit

about

the

LC-90

and

how

to

use

it.

The

next

section

will

go

de

ep

er

into

more

of

the

quite

incredible

things

that

the

LC-90

can

do

for

you.

In

this

section

we

will

start

dealing

with

funetions

that

will

allow

you

to

plan,

and

then

actually

make,

voyages

to

destinations

of

your

choice.

You

may

wish

to

go

to

a

specific

position

such

as

a

partieular

buoy,

or

you

may

wish

to

return

to

a

place

where

the

fishing

was

good

previously.

If

you

are

a

commercial

fisherman

you

may

want

to

go

back

to

an

area

where

you

know

where

the

"hangs"

(net

hang-ups)

are

so

that

you

may

be

able

to

avoid

them

and

not

tear

up

your

nets.

ENTRY

OF

A

POSITION

INTO

A

WAYPOINT

(WPT

Mode)

In

Navigation

terminology,

a

partieular

location

is

known

as

a

"Waypoint,"

whether

it

be

a

starting

point,

a

destination

point

or

an

intermediate

point

on

a

voyage.

The

LC-90

is

capable

of

waypoint

entry

by

four

different

methods:

a.

By

Latitude

and

Longitude

coordinates

of

a

location.

b.

By

TD's

(Time

Differences)

of

a

location.

c.

By

using

the

fEVTI

button

to

store

present

position

in

a

waypoint.

d.

By

Range

and

Bearing

from

your

present

position.

In

the

early

days

of

Loran-C

technology

many

people

became

quite

accustomed

to

the

use

of

TD's;

after

all,

TD-only

receivers

were

the

only

ones

available

at

reasonable

prices.

Many

commercial

fishermen

especially

developed

an

extensive

list

of

TD's

where

they

had

experienced

either

good

fishing

or

had

encountered

"hangs."

Modern

receivers,

with

their

ability

to

use

Latitude/Longitude

direetly,

are

easier

to

use

for

most

people

since

all

navigation

charts

are

printed

with

Latitude

and

Longitude

coordinates,

and

only

a

relatively

few

charts

are

available

with

Loran-C

TD

overlays.

Many

commercial

fishermen

with

their

hang

logs

in

TD's

will

find

that

it

is

a

good

idea

to

write

down

the

corresponding

Latitude/Longitude

coordinates

next

to

their

older

TD

information

when

they

make

a

TD

to

L/L

conversion

while

ente

ring

specific

positions

as

waypoints.

(See

the

Advanced

Level

Operation

section

for

a

tip

on

how

to

enter

TD's

as

waypoints,

while

still

retaining

the

advantages

of

automatic

ASF

compensation.)

The

other

methods

will

be

used

during

a

voyage,

when

you

want

to

record

an

interesting

place

instantly,

such

as

for

example

a

good

fishing

spot

you

happen

across.

Now

before

you

actually

start

punching

in

numbers,

take

a

chart

of

your

area

and

choose

a

buoy

or

some

other

position

you

know

and

write

down

on

a

scratchpad

the

Latitude

and

Longitude

coordinates

for

your

waypoint.

Using

a

divider,

measure

the

distance

from

your

present

position

to

your

waypoint,

and

then

write

that

down.

Now

measure

the

magnetic

bearing

from

your

present

position

to

your

chosen

waypoint

using

parallel

rulers

and

write

that

information

down.

What

we

will

be

doing

is

comparing

the

numbers

you

have

derived

for

Range

and

Bearing

with

those

from

the

LC-90.

31

32

Waypoint

Entry

By

Latitude/Longitude

Coordinates

(WPT

Mode)

:

Entry

of

a

position

into

a

waypoint

is

a

two-step

process.

First

you

assign

a

number

to

identify

a

particular

waypoint,

and

then

you

en

ter

the

de

sired

position

into

that

waypoint.

The

LC-90

has

one

hundred

waypoints

into

which

position

information

may

be

ente

red.

These

are

numbered

from

"zero-zero"

to

ninety-nine.

The

LC-90

allows

you

to

look

at

the

position

already

stored

in

each

numbered

waypoint

by

specifying

the

waypoint

and

then

using

either

the

L/L

or

the

TD

format

to

read

the

stored

position.

Some

people

might

search

through

the

waypoints

already

stored

in

the

unit

in

order

to

find

an

empty

waypoint

in

which

to

insert

new

information.

However,

it

is

probably

less

confusing

to

insert

data

sequentially,

starting

at

waypoint

one

and

proceeding

upwards,

one

by

one,

in

the

sequence

that

the

waypoints

will

actually

be

encountered

on

the

voyage.

Obviously,

it

1

s

important

that

you

write

down

your

voyage

plan

in

your

log

so

that

you

have

a

permanent

record

of

which

waypoint

is

which.

Some

operators

prefer

to

reserve

Waypoint

ninety-nine

as

a

sort

of

"scratchpad,"

so

that

any

interesting

position

information

they

might

for

instance

hear

on

the

radio

may

be

entered

at

the

moment

it

is

heard.

Any

position

data

that

have

been

stored

in

other

waypoints

thus

will

not

be

disturbed,

or

even

lost,

in

the

heat

of

the

moment.

Waypoint

"UO"

is

a

special

one.

It

is

reserved

for

use

when

your

present

location

is

used

in

a

navigation

calculation.

This

will

be

explored

in

more

detail

later.

Conceptually,

waypoints

are

best

thought

of

as

being

"Waypoints

From"

a

desired

origin

or

as

"Waypoints

To"

a

desired

destination.

Several

navigation

functions

that

will

often

be

used

in

planning

voyages

make

this

distinction

between

"From"

and

"To,"

even

though

any

one

particular

waypoint

may

be

used

for

either

purpose,

since

each

waypoint

defines

a

specific

location

on

earth,

whether

you

want

to

go

towards

it

or

away

from

it.

Let

us

assume

for

purposes

of

illustration

that

we

wish

to

enter

the

Latitude

and

Longitude

position

of

San

Francisco

into

Waypoint

Zero

Seven.

The

coordinates

are:

37

degrees,

40.00

minutes

North

Latitude,

and

122

degrees,

24.00

minutes

West

Longitude.

You

would

of

course

enter

your

own

approximate

L/L

coordinates.

The

sequence

of

key

punch

operations

would

be

as

follows:

1.

M

ove

the

right

arrow

key

un

til

the

Mode

indicator

arrow

is

directly

over

the

"WPT"

label

on

the

front

panel

beneath

the

display.

Observe

the

waypoint

number

in

use

there

now.

The

waypoint

number

is

located

on

the

third

line

next

to

the

"WPT"

label.

The

first

digit

of

the

waypoint

number

will

be

flashing

to

indicate

that

the

data-entry

cursor

is

presently

at

this

location.

The

latitude

and

longitude

of

the

waypoint

in

use

at

this

time

are

displayed

on

lines

four

and

five

of

the

display.

If

you

want

to

see

the

TD

'

s

that

correspond

to

the

L/L

for

this

waypoint,

hit

the

pTD

<-»

L/Ll

key.

Hit

the

key

again

to

get

back

to

the

L/L

read

out.

Note:

if

the

L/L

is

zero

degrees

latitude

and

longitude

in

a

waypoint,

the

corresponding

TD's

will

be

non-zero

values

representing

the

TD's

that

would

be

present

at

zero

latitude,

zero

longitude.

The

exact

value

of

these

TD's

will

change

depending

on

the

GRI

in

use

by

the

LC-90

at

that

moment.

The

important

thing

to

remember

is

that

the

LC-90

stores

positions

in

L/L

format

in

its

waypoint

memory,

and

that

an

L/L

position

of

zero/zero

degrees

indicates

that

the

waypoint

is

empty.

Fig.

17

WPT

Mode

Screen

2.

N

ow

respecify

the

waypoint

to

be

waypoint

zero

seven.

Use

the

following

touchpad

sequence:

FCLRl

Fol

m

r

ENTl

Note

that

the

entry

of

the

leading

zero

is

necessary.

Entering

"7"

after

!

CLR

|

will

simply

cause

the

LC-90

to

ignore

the

input

as

invalid.

If

waypoint

zero

seven

is

presently

empty,

you

will

see

zeroes

on

lines

four

and

five.

Now

go

ahead

and

enter

the

San

Francisco

numbers,

as

the

cursor

has

automatically

advanced

to

the

next

line

after

you

hit

|~ENT

|

.

3.

!

CLR

|

mmmm

lENTl

37°38.00'

N

Fclri

m

p2i

m

m

m

m

m°

2

4

.

o

o

-

w

Note

that

the

entry

of

trailing

zeroes

is

optional.

The

LC-90

senses

when

traili

ng

zeroes

a

re

necessary

and

adds

them

as

needed.

Now

you

may

hit

the

|TD

<-»

L/L

I

key

to

see

what

TD's

correspond

to

the

L/L

you

just

entered.

Note

also

that

if

we

were

operating

in

Southern

Latitudes

and

Easterly

Longitudes

we

would

have

to

override

the

North

and

West

defaults

that

the

LC-90

has

been

normally

set

up

to

use.

For

example,

if

the

position

of

our

Waypoint

zero

seven

were

37

degrees,

40.00

minutes

South

Latitude,

and

122

degrees,

24.00

minutes

East

Longitude,

we

would

punch

in

the

following

sequence.

I

CLR

|

m

|T|

[3]

[8]

F7

7

!

|

ENT|

37°38.00'

S

[CLR]

[T|

\J\

[2]

QT)

[4]

f+7^1

FenYI

122°24.00'

E

Waypoint

Entry

By

TD's

(WPT

Mode)

:

The

second

method

of

specifying

a

waypoint

position

is

by

TD'

s.

This

process

involves

converting

the

TD's

to

appropriate

Latitude/Longitude

coordinates

and

then

using

those

coordinates

for

the

waypoint.

This

sounds

like

an

involved

process,

but

the

LC-90

makes

it

straightforward,

provided

that

the

operator

uses

some

degree

of

caution.

Back

in

the

section

on

How

Loran-C

Works

we

stated

that

Loran-C

TD's

form

hyperbolic

shaped

lines

and

showed

a

simplified

drawing

(Fig.

18).

We

have

reproduced

that

figure

here

to

refresh

your

memory.

33

34

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