SEA 1612C,1612WX,1612W Instruction And Maintenance Manual

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---­A UNIT

OF DATAMARINE

INTERNATIONAL

I

NC.

sEA

1612C

r161

zVU

r161zWX

AUTOMATIC

ANTENNA

TUNER

INSTBUCTION

AND

MAINTENANCE

MANUAL

@ Copyright

1993, 1994

SEA Inc.

All

rights reseryed.

SEA Inc.

7030 2201h

sr, s.w.

Mountlake

Terrace,

Washington

98049

(425)

771-?182*

FAX:

(42s)

771-2650

MAN-1612C
Revision

D

July 2001

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IMPORTANT

NOTICE

TO

INSTALLERS

The

1ffi2D is

designed

to be

weatherproof

when

properly

installed.

Be

sure

all

fasteners

are tight

and

cable

entries

sealed.

No warranty

claims

will be

allowed

for

water

damage

to the

contents.

2.

2.1

2.2

TABLE

OF CONTENTS

1.

1.1

1.2

1.3

1.4

PAGE

GENERAL

INFORMATION...

.....1 . 1

Overall

Description

............

.......-.......1

-

1

Electrical

Configuration

..-.............1

-2

Mechanical

Configuration

...............1-2

Weather

Housing

.1..;1...........| ..............1

-4

SPECIFICATIONS AND

PARTS FURNISHED........,.....,....2. 1

Specif

ications............

......2-

1

Parts Furnished...............

.2-2

PR|NC|PLE OF OPERAT!ON...-...

.......,....3

-

1

Networks...........

..................3

-

1

Schematic

Diagrams

......3 - 1

Auto Tune Operation

...........3 - 1

Vswr Detector

..................3

-

3

Frequency Counter...

............3

-

3

Phase Detector

.................3

-

4

The Control

Computer...............

............3

-

4

Initialization

And Fireup

...............3

-4

lnformation

Flead

.............3

-

5

Information

Write......

,.....3

-

5

The Progr:am..............

.............3

-

5

INSTALLATION

PFOCEDURE

....4.

1

Mechanicat

Considerations.....

.............4

-

1

Electrical

Conslderations.,-......

.........-.4

-2

Electrical

Checkout..............

............4 - 3

TROUBLESHOOTING.......

....--.-..-5

-

1

COUPLER

WILL

NOT

TUNE

.

NO REI-AY

ACTION

.-.........5

-

1

RELAYS

OPERATE

BUT NO

TUNE

....5

-

2

C,OUPLER

TUNES

BUT

NO MEMORY

..5 - 3

TUNEB

WILL

NOT DEMAND

ruNE...............

.....,,5.3

SCHEMATIC

AND CIRCUIT

BOARD

LAYOUT

SEA

1612C COMPONENT

PARTS

LIST

3.

3.1

3.2

3.3

3.4

3.5

3.6
3,7

3.8

3.9

3.10

3.11

4.

4.1

4.2

4.3

5.

5.1

5.2

5.3

5.4

6.
7-

LISTOF

FIGURES

FIG.

#

FIGURE

MME

1.3

Outline and

Mounting

Dimensions.-...

3.1 Network

Configurations

.....,.....3-2

6,1

Antenna

Tuner Schematic

(ASY-1616-01)

6.2

Circuit

Board Layout

1.1

GENEHAL

INFORMATION

OVERALL DESCRIPTION
The

SEA

1612C

is a

fully

automatic

antenna

tuning

unit,

designed for

the

MF-HF spectrum

and

compatible

with a wide

variety

of

antenna

systems.

This

product

features an

advanced

microprocessor-based

tuning

algorithrn

which

allows

it

to

tune up

on

normal

voice

signals f rom

the

associated transmitter

and

also

includes

a

"learning"

algorithm

which

allows

the control

computer to remember

which

network

constants

are required

for

a

given

operating

frequency. The

memory feature

permits

the

antenna tuner,

once the

"learning"

operation

is

completed, to retune

a

given

frequency in approximately

20 milliseconds.

This

is

less

than the

time required

to say

"hello".

Antenna tuner

operation

is

completely

automatic

and requires

no

operator

intervention.

lf

the antenna system

is

altered

or

replaced,

the

tuner

will automatically

"relearn"

the

required networks.

During

the

learning

period,

operation

is somewhat

slower

and,

depending on the

particular

frequency/antenna

combination,

up

to

5 seconds

may be required to achieve

a

matched

condition. When the antenna

has

been

properly

malched,

the tuner signals this condition

by

pulling

a control

line

low. The

control signal may be

used to

operate

an

"all

tuned"

indicator

at the

operators'

T-Fl

position.

Such

an

indicator

is

provided

in

the

SEA

222,

SEA

322

and SEA 225

radiotelephones.
The SEA 1612C

also includes

a

"DEMAND

TUNE" function

and

a

'TUNE

LOCKOUT"

capability.

The

"DEMAND

TUNE"

function

allows the

user

to

force the

antenna

tuner to

retune

on

demand.

This

permits

"overwriting"

previously

stored

tuneup

information

when

desired.

The'TUNE

LOCKOUT"

feature

is

useful

when

two

or

more

transmitters

are

co-located,

or

when

it

is

desirable

to

inhibit the

AUTO

TUNE

function

for any reason.

1-1

E.G.: when

two

antennas

are

in

close

proximity,

it is

possible

that transmitting

on

one

antenna

may

cause

considerable

RF

to

be

coupled

into

the

adjacent

antenna.

This

can

cause

the

tuner

to

reset,

disturbing

the

operation

of the

radiotelephone.

In

such

cases,

the

"TUNE

LocKour''

feature

of

the sEA

1612c

can

be

used

to

prevent

the

SEA

1612C

from

entering

the

tune

mode

until

the radiotelephone

it is

associated

with is

actually

transmitting.

1

,2

ELECTRICAL

CONFIGURATION

The

sEA

1612c

matches

the

complex impedance

of the

antenna system

to

a nominal

50 ohms

by-'selecting."the:..,proper

network

from

a

possible

combination

of 64

values

of input

c,

32

values

of

output

c

and

s1z

values

of

series

L.

Network

configuration

is

automatically

determined during

the tune

cycle and

may

be

either

a Pl

network

or either

of

two

types

of L network.

whenever possible,

the

L

network

will

be

selected f

or

maximum

eff

iciency.

Tuneup

is

entirery

automatic

and

may

be

accomplished

on

voice

signals,

making

it

unnecessary

to

provide

a

"low

power

tune"

mode

in

the

trans

m itter.

1.3

The

various

RF

sensors

in the SEA

function

down

to

power

levels

of

feature makes

the SEA

1612C

equipment

such as

the SEA 225

circuitry

to

reduce

the output

power

hish

VSWR.

MECHANICAL

CON

FIGU

RATION

1612C are designed

to

10

to 20 watts. This

compatible

with radio

which is equipped with

level in

the

presence

of

All

of the circultry

of the SEA 1612C ls contained

on

printed

circuit

board PCB-1616-01.

This

printed

circuit board

is

mounted

on

an

aluminum shield

plate

with

six 6-32 stainless

steel screws. The

shield

plate

is held in

the

molded

weather

housing wlth four 10-24

stainless steel screws.

(Figure

1.3

shows the

outline

and

mounting

dimensions of the

molded

weather housing.)
The

printed

circuit board

is

solder-masked

which

helps to

prevent

corrosion and

moisture

problems.

1-2

12.6"

I

-

A

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16:1'

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SEA

1612C

ANTENHA

TUNER

OUTLINE

& MOUNTING

DIMENSIONS

FIGURE

1,3

1-3

1.4

Both

the

so-239

RF

connector

and

the

six

pin

interface

connector

strip

are

mounted

on

the

printed

circuit

board

itself.

The

interface

connector

accepts wire

ends

directly,

eliminating

any

requirement

for

special

lugs

or

lugging

tools.

A PL-259

type

FIF

plug

must

be fitted

to the

coaxiar

feed line.

WEATHER

HOUSING

The

sEA

1612c

antenna

tuner is housed

in

a weatherproof

molded

case

designed

to withstand

the

environmental

conditions

encountered

aboard

ship

when

mounted

on

the

weather

decks.

The

internal

construction is

designed

to

withstand

the

shock

and

vibration

of marine

service.

corrosion-resistant

hardware

and

passivated

alroys are

employed

throughout.

stufflng

glands

for

the

RF and

Dc

cables are

provided

on

the

lower

edge

of

the

weather

housing,

along

with

a 1t4-ZO

stainless

steel

ground

stud.

The

antenna

connects to

the

ceramic

insulator

on the

top of

the

weather

housing.

I.5

SPECIAL

MODELS

OF THE

16I2C

The

l6l2C

is

avaitable

in

the following

two

optional

configurations:

thc l6lZW

and

thc

l6lZWX.

The l6l2W

is a i6t2C

with a gas

filled

spark

gap

tubc installed

on rhe

printed

circuit

board assembly.

This

part

will

shunt excessivcly

high voltages

to the

ground

plane (near

lightning

strikes)

to

prevent

darnage to thc RF sensors. The

l612WX

is

a l6l2W

with a RF

relay

assembly that

shorts

the

antenna output

connector

to

ground

when

then

power

to the

couplcr

is

switched

OFF. Please contact

the

factory

for additional

information.

1-4

2.

SPECIFICATIONS

AND PARTS

FURNISHED

2.1

SPECIFICATIONS

Frequency

Range

1.6 to

30.0 MHz

RF

Power

Capability

150 watts Peak

Envelope Power

(PEP)

Input

lmpedance

50 ohms

VSWR

<2:1

Power Requirements

13.6

VDC

negative

ground

Operating Current

2

Amps max.

Tuning

Time

"Learn

Mode",

typically

less

than 5

seconds
"Educated

Mode", approximately

20

milliseconds

Recommended 23-75

ft.

(7-23

meters) 1.6-30

MHz

Antenna

Length I ft.

(2.7

meters) whip 3-30

MHz

Mounting

Any

position

Environmental Temp.

Range

-30"C

to +60oG

Size

in:

15 X 12 X

3.9

mm:

381

X

304.8

X

99

Weight

10

1bs./4.5

kgs.

Case Construction

Molded

Weatherproof

Control

Cable

No.

20 Gauge, 3 to

5 conductors,

shielded

(not

supplied)

2-1

2.2

PARTS

FURNISHED

1.

Antenna

Tuner

with

Cover

and

Bushings

2.

Instruction

Manual

2-2

3.

3.1

PRINCIPLE

OF

OPERATION

NETWORKS

Figure

3.1 shows

the schematic

diagram for

the two basic

network

configurations.

Note

that the

nln

network

as viewed

from

the

generator

may be

configured

as either

"C

in" or"C

out",

whichever

is

required

by

the

load.

In

either case, the

end

of the

network containing

the shunt C

element will be the

HIGHER

impedance

end of the network.

SCHEMATIC

DIAGHAMS

Figure

6.1

is

the schematic diagram

of the antenna tuner. RF

input is

applied

to

UHF fitting J1, 13.6 VDC is

connected to

the terminals marked

GND

and + on

P1

(Pins

1 and 2

respectively),

and an

appropriate

antenna

and

ground

system

are connected to feedthrough

insulator and

stainless

steel

stud

respectively.

The

"TND"

flag line

(Pin

4 on P1)

is

connected to the remote indicator

device

used. When

the SEA

16'1

2C is

used with the

SEA

222,

SEA 322 or

SEA 225

radiotelephone,

the flag line

is

connected

to the

"TND"

line

on

the

radio's

rear

panel

connector.

AUTO TUNE OPERATION
When RF

power

is

applied

to

the SEA

1612C

it is first

passed

through an

array of detectors

which

determine the

frequency,

load

VSWR

and the reactance sign.

Forward

power

is

continuously

monitored,

since

the

control

computer

requires

an

indication

of

both forward

and

reflected

power

in

order

to

allow

tuning

to

proceed.

ln

practice,

the

forward

power

detector is

used

by the

computer

as

a

truth

check

to insure

that

the

measurements made

are

indeed

a result

of

applied

RF

and

not

spurious

levels

from

the

data

conversion

system.

Tuneup

will

ONLY

proceed

when

sufficient

forward

power

is

present

to

provide

this

truth

check.

After

passing

through

the

detector

system,

the

FIF

is

applied

to the

tuner

array.

This

consists

of 6 capacitors

in

shunt

on the

input

arm

of

the

network,

arranged

in

binary

increments,

I inductors

in

the

series

arm,

arranged

in

binary

increments,

and

5

more

capacitors

in

shunt

on the

output

arm,

also

arranged

in

binary

increments.

Relays are

provided

in

conjunctlon

with

each

3.2

e.)

\r.

(J

3-1

3.4

lumped

constant

which

allow

removal

or

entry

as

desired.

Thus,

it is

possible

through

the

manipulation

of

26 rerays

to

build

a

network

having

64

values

of input

shunt

c, 32

values

of

output

shunt

C,

and

up

to

512

values

of

series

L.

VSWR

DETECTOR

Current

transformer

T1

and voltage

transformer TZ,

in

conjunction

with

termination resistors

R1

and

RS

make

up a

dual

directional

coupler.

This directional

coupler

is inserted

in

the

50

ohm

transmission

line between

the input

connector,

J1,

and

the

tuning network.

A

sample of FORWAFID

power

appears

across

termination

Rl,

while

d,.simple

of,'REFLECTED

power

appears

across

termination

R5.

The FORWARD

and

REFLECTED

power

RF

samples

from

the

directional coupler

are detected

by diodes

CR1

and CR3.

H/C filter networks

are

provided

on

both

the FORWAHD

power

and

REFLECTED power

signals

and

both

are clamped

to the +5 Volt rail

through

diodes CRZ

and

CR4 to

prevent

overdriving

the

A/D

converter

inputs

of CPU

chip, U5.

With

voltages

representing

both FORWARD

and

REFLECTED

power

available

to the

CPU,

it

is

possible

to compute

the

VSWR

continuously

during

the tuning

process.

FREQJENCY

CCTJN]ER

The

memory

storage

system in

the SEA

1612C

is based on the

fact that the control

computer

senses what

frequency is in

use.

This

is

accomplished

by applying

a

prescaled

sample

of

the

RF

signal to

the

the

CPU timer

input.

The

prescaler

consists of U1A,

U2

and U3.

A sample

of the RF

signal is

applied through a biased clamping

network

consisting

of

CRg,

CR10, R17, R18, R19

and R20,

to the input

of CMOS

schmitt

trigger U1A. The

shaped

output

signal is

then divided

by

2048 through

cascaded

counters

U2 and

U3.

The

output from the

counter

train

also serves as an interrupt

generator

for the CPU,

acting as

an

'FlF

present"

indicator.

3.5

3-3