Furuno LC-90 Mark-II Bedienungsanleitung

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3

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|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