Onwa KR-12X8 User Manual

KR-12X8/15X8

OPERATOR'S MANUAL

KR-1238/1268
KR-1538/1568

TFT LCD COLOR MARINE RADAR

SAFETY INSTRUCTIONS

"DANGER","WARNING" and "CAUTION" notices throughout this manual. It is
the responsibility of the operator and the installer of the equipment to read,
understand and follows these notices. If you have any questions regarding
these safety instructions, please contact a ONWA agent or dealer.

WARNING

Do not open the equipment.

Hazardous voltage which can cause electrical shock, burn or serious
injury exists inside the equipment. Only qualified personnel should work
inside the equipment.

Wear a safety belt and hard hat when working on the antenna unit.

Serious injury or death can result if someone falls from the radar antenna

mast.

Stay away from transmitting antenna.

The radar antenna emits microwave radiation which can be harmful to
the human body, particularly the eyes. Never look directly into the
antenna radiator from a distance of less than 1 m when the radar is in
operation.

Turn off the radar power switch before servicing the antenna unit.
Post a warning sign near the switch indicating it should not be
turned on while the antenna unit is being serviced.

Prevent the potential risk of someone begin struck by the rotating
antenna and exposure to the RF radiation hazard.

Do not disassemble or modify the equipment.

Fire electrical shock or serious injury can result.

Turn off the power immediately if water leaks into the equipment or the
equipment is emitting smoke or fire.

Continued use of the equipment can cause fire or electrical shock.

Do not place liquid-filled containers on the top of the equipment.

Fire or electrical shock can result if a liquid spills into the equipment.

CAUTION

Use the proper fuse.

Use of a wrong fuse can result in fire or permanent equipment damage.

Do not use the equipment for other than its intended purpose.

Personal injury can result if the equipment is used as a chair or stepping stool, for example.

Do not objects on the top of the equipment.

The equipment can overheat or personal injury can result if the object falls.

TABLE OF CONTENTS

FOREWORD 1

KR-1238/1538 SPECIFICATION 2

KR-1268/1568 SPECIFICATION 4

CONFIGERATION OF KR-1238/1268/1538/1568 6

1. PRINCIPLE OF OPERATION 7

1.1 What is Radar? 7

1.2 How Ships Determined Position Before Radar 7

1.3 How Radar Determines Range 7

1.4 How Radar Determines Bearing 7

1.5 Radar Wave Speed and Antenna Rotation Speed 7

1.6 The Radar Display 8

2. BASIC OPERATION 9

2.1 Control Description 9

2.2 Display Indication and Markes 10

2.3 Turning the Radar On and Off 11

2.4 Transmitting 11

2.5 Echo area 11

2.6 11Reference Position

2.7 Own Ship Marker 13

2.8 Stand-by 13

2.9 Selecting the Range 14

2.10 Adjusting Picture Brilliance 14

2.11 Setup display color 15

2.12 Adjusting Receiver Sensitivity 15

2.13 Adjusting the A/C SEA Control (reducing sea clutter) 16

2.14 Apply the A/C RAIN (reducing rain clutter) 17

2.15 Erasing the Heading Line 18

2.16 Measuring the Range 18

2.17 Measuring the Bearing 20

2.18 Using the Offset EBL 21

2.19 Shifting (off centering) the Pcture 23

2.20 Zoom 23

2.21 Outputting Target Position 24

3. MENU OPERATION 25

3.1 Basic Menu Operation 25

3.2 Selecting the Presentation Mode 26

3.3 Magnifying Long Range Echoes (echo stretch) 26

3.4 Echo Trail 27

3.5 Suppressing Radar Interference 28

3.6 Selecting Pulse 29 Length

3.7 Guard Alarm 30

3.8 Watchman 32

3.9 Display Navigation Data 33

3.10 34FUNCTION MENU Description

3.11 VIDEO MENU Description

3.12 35Function Keys

3.13 36Suppressing Nois

3.14 Adjusting Brilliance of Markers 36

35

4. FALSE ECHOES 37

4.1 Multiple Echoes 37

4.2 Side-lobe Echoes 37

4.3 Indirect Echoes 38

4.4 Blind and Shadow Sectors 39

5. MAINTENANCE & TROUBLESHOOTING 40

5.1 Preventative Maintenance 41

5.2 Replacing the Fuse 41

5.3 Troubleshooting 41

5.4 Self Test 41

5.5 Life Expectancy of Magnetron 43

6. INSTALLATION 44

6.1 Antenna Unit Installation Sitting handling considerations 44

6.2 Display Unit Installation Mounting considerations 52

6.3 Exchange of Fuse for 24/32V Power Supply 55

6.4 Checking the Installation 55

6.5 Adjustments 55

7. ARPA 61

8. AIS 71

9. DISPLAY UNIT SIZE 79

10. ABBREVIATIONS 83

FOREWORD

Thank you for your choice of ONWA MODEL KR-12X8/15X8 Marine Radar.
The radar is designed and constructed to meet the rigorous demands of the marine
environment. However, no machine can perform its intended function unless
properfly installed and maintained. Please carefully read and follow the
recommended procedures for installation, operation and maintenance. While this
unit can be installed by the purchaser, any purchaser who has doubts about his or
her technical abilities may wish to have the unit installed by a ONWA
representative or other qualified techician. The importance of a through installation
can not be overemphasized. We would appreciate hearing form you, the end user,
about whether user, about user, about whether we are achieving our purposes.

Thank you for considering and purchasing ONWA equipment.

Features

Your radar has a large variety of functions, all contained in a remarkably small

cabinet.

The main features of the MODEL KR-12X8/15X8 are.

Traditional ONWA reliability and quality in a compact, lightweight and low-cost

radar.

Durable brushless antenna motor.

On-screen alphanumeric readout of all operational information.

Standard features include EBL (Electronic Bearing Line), VRM (Variable Range

Marker), Guard Alarm, Display Off Center, and Echo Trail.

Watchman feature periodically transmits the radar to check for radar targets

which may be entering the alarm zone.

Ship s position in latitude and longitude and range and bearing to waypoint,

'

and ship's speed/ heading/course can be shown in the right hand side text area.

(Requires a navigation aid which can output such data in IEC61162 format.)

Zoom feature provided.

1

KR-1238/1538 SPECIFICATION

ANTENNA UNIT

1. Radiator Slotted waveguide array

2. Radiator length 55 cm

3. Horizontal beamwidth 4

4. Vertical beamwidth 25

5. Sidelobe
Within 20 off mainlobe; less than -18 dB
Outside 20 off mainlobe; less than -23 dB

6. Polarization Horizontal

7. Antenna rotation speed 24 rpm ( 2)

8. Wind resistance Relative wind speed 100 knots (51.5 m/s)

:

:

:

:

:

:

:

:

TRANSCEIVER MODULE (contained in radome)

1. Transmitting tube MSF1421B or MAF1421B

2. Frequency 9410 MHz 30MHz

3. Peak output power 4kW nominal

4. Pulselength & pulse repetition rate

:

:

:

:

0.08 S, 2100 Hz (0.125, 0.25, 0.5, 0.75, 1.5nm)

0.3

0.8 S, 600 Hz (3, 4, 6, 8, 12, 16, 24, 36nm)

5. Warm up time: 1:30 minutes

6. Modulator: FET switching method

7. I.F.: 60MHz

8. Tuning: Automatic or manual

9. Receiver front end: MIC (Microwave IC)

10. Bandwidth:
Tx pulselength 0.3 S and 0.08 S: 25MHz
Tx pulselength 0.8 S: 3MHz

11. Duplexer: Circulator with diode limiter

S, 1200 Hz (1.5, 2, 3nm)

2

DISPLAY UNIT

1. Indication system LCD digital display

2. Display 12 or 15 LED backlight, 32-bit TFT Color LCD Display

3. Range scale (nm)
Range, Range interval and no. of Rings:

0.125(0.0625,2), 0.25(0.125,2), 0.75(0.25,3), 1(0.25,4), 1.5(0.25,6),
2(0.5,4), 3(0.5,6), 4(1,4), 6(1,6), 8(2,4), 12(2,6), 16(4,4), 24(4,6), 36(6,6)

4. Bearing resolution 4

5. Bearing accuracy Within 1

6. Range discrimination Better than 30 m

7. Range ring accuracy 0.9% or range in use or 8 m, whichever is larger

8. Minimum range Better than 25 m

9. Markers
Heading line, Bearing scale, Range ring, VRM, EBL Tuning indicator,
Cursor, Alarm zone, North mark (heading sensor input required)

10. Alphanumeric indication
Range, Range ring interval, Pulselength, Interference rejection (IR), VRM,

:

:

:

:

0.5(0.125,4),

:

:

:

:

:

:

EBL, Stand-by (ST-BY), Radar alarm, Echo stretch (ES), Range to cursor,
Bearing to cursor, Echo trailing (TRAIL), Trail time, Trail elapsed time,
Navigation data (navigation input required), heading (HDG, heading sensor
input required)

11. Vibration
Vibration Total amplitude
1 to 12.5 Hz 1.6mm

12.5 to 25 Hz 0.38mm
25 to 30 Hz 0.10mm

12. Temperature
Antenna unit; -25 to + 70
Display unit; -10 to + 50

13. Humidity
Relative humidity 93% or less at + 40

14. Power supply & power consumption : 12V, 24V or 32VDC (10.5V to 40
VDC) 60W

:

:

:

:

15. Compass safe distance

Display unit 0.75m 0.6m

:

Standard Compass

3

Steering Compass

1.75m3.1mAntenna unit

KR-1268/1568 SPECIFICATION

ANTENNA UNIT

1. Radiator: Slotted waveguide array

2. Radiator length 120 cm

3. Horizontal beamwidth 1.9

4. Vertical beamwidth 22

5. Sidelobe
Within 20 off mainlobe; less than -24 dB
Outside 20 off mainlobe; less than -30 dB

6. Polarization Horizontal

7. Antenna rotation speed 24 rpm

8. Wind resistance Relative wind speed 100 knots(51.5 m/s)

:

:

:

:

:

:

:

TRANSCEIVER MODULE (contained in antenna)

1. Transmitting tube MAF1421 or MSF1421

2. Peak output power 6KW nominal

3. Pulselength & pulse repetition rate

0.08 S, 2100 Hz (0.125, 0.25, 0.5, 0.75, 1.5nm)

0.3

S, 1200 Hz (1.5, 2, 3nm)

:

:

:

0.8 S, 600 Hz (3, 4, 6, 8, 12, 16, 24, 36, 48, 64nm)

4. Bandwidth:
Tx pulselength 0.3 S and 0.08 S: 25MHz
Tx pulselength 0.8 S: MHz

5. Other: See KR-1238/1538

DISPLAY UNIT

1. Range scale (nm):
Range, Range interval and no. of Rings:

0.125(0.0625,2), 0.25(0.125,2), 0.75(0.25,3), 1(0.25,4), 1.5(0.25,6), 2(0.5,4),
3(0.5,6), 4(1,4), 6(1,6), 8(2,4), 12(2,6), 16(4,4), 24(4,6), 36(6,6)
64(16,4)

2. Compass safe distance:

Standard Compass

Display unit 0.75m 0.6m

Steering Compass

, 48(8,6),

0.91m1.3mAntenna unit

3. Power supply & power consumption: 12V, 24V or 32VDC (10.5V to 40VDC)
60W.

4

INTERFACE (NMEA0183)IEC61162

Input data sentences:

Own ship`s position: GGA>RMA>RMC>GLL
Speed: RMA>RMC>VIG>VHW
Heading (True): HDT>HDG*>HDT*>VHW>VHW*
Course (True): RMA>RMC>VTG
Course (Magnetic):
Waypoint (Range, Bearing): RMB>BWC>BWR
Loran time difference: RMA>GLC>GTD
Water depth: DPT>DBT
Water temperature: MDA>MTW
XTE: RMB>XTE>APB
*: Calculated value based Magnetic variation.

AIS: VDO>VDM>ACA>ACS>ALR>ACK

VTG>RMA*>RMC

Output data sentences:

TLB>TLL>TTD>TTM

5

CONFIGERATION OF KR-1238/1268/1538/1568

ANTENNA UNIT

NMEA-1

KR-1238/1538

Antenna cable
KRC-003-15/20/30
15/20/30m

5 Pin

KR-1268/1568

Display UNIT

UPGRADE

4 Pin

NMEA-2

6 Pin

VGA

7 Pin

RS422

8 Pin

3M

10.5 to 40VDC

6

1. PRINCIPLE OF OPERATION

1.1 What is Radar?

The term "RADAR" is an acronym meaning "RAdio Detection And Ranging".
Although the basic principles of radar were developed during World War II,

echoes as an aid to navigation is not a new development.

1.2 How Ships Determined Position Before Radar

Before the invention of radar, when running in fog near a rugged shoreline,
ships would sound a short blast on their whistles, fire a shot, or strike a bell.
The time between the origination of the sound and the returning of the echo
indicated how far the ship was from the cliffs or the shore. The direction from
which the echo was heard indicated the relative bearing of the shore.

1.3 How Radar Determines Range

Radar determines the distance to the target by calculating the time difference
between the transmission of a radar signal and the reception of the reflected
echo. It is a known fact that radar waves travel at a nearly constant speed of
162,000 nautical miles per second. Therefore the time required for a transmitted
signal to travel to the target and return as an echo to the source is a measure
of the distance to the target. Note that the echo makes a complete round trip,
but only half the time of travel is needed to determine the one-way distance to
the target. This radar automatically takes this into account it making the range

calculation.

1.4 How Radar Determines Bearing

The bearing to a target found by the radar is determined by the direction in
which the radar scanner antenna is pointing when it emits an electronic pulse
and then eceives a returning echo. Each time the scanner rotates pulses are
transmitted in the full 360 degree circle, each pulse at a slightly differentbearing
from the previous one. Therefore, if one knows the direction in whichthe signal
is sent out, one knows the direction from which the echo must return.

1.5 Radar Wave Speed and Antenna Rotation Speed

Note that the speed of the radar waves out to the target and back again as echoes
is extremely fast compared to the speed of totation of the antenna. By the time
radar echoes have returned to the scanner, the amount of scanner rotation after
initial transmitting of the radar pulse is extremely small.

7

1.6 The Radar Display

The range and bearing of a target is displayed on what is called a Plan Position
Indicator (PPI). This display is essentially a polar diagram, with the transmitting
ship's position at the center. Images of target echoes are received and displayed
at their relative bearings, and at their distance from the PPI center. With a
continuous display of the images of targets, the motion of the transmitting ship
is also displayed.

Own ship
(radar)

(A) Bird's eye view of situation

Figure 1-1 How radar works

Targets

Own ship
in center

(B) Radar picture of (A)

Heading line

Range and bearing of
a target, relative to own
ship, are readable on
the PPI

8

2.1 Control Description

Brief press:
Displays the data of target
selected with the cursor
Long press:
Terminates plotting of the target
selected with the cursor.

2. BASIC OPERATION

Omnipad
Shifts cursor, VRM and EBL;
select items and options on
menu.

SELECT
CANCEL

ACQ

ENTER

(1) Acquires the target selected
with the ominipad.
(2) Registers selection on
menus.

Opens/closes menus

Selects:
EBL1/EBL2/VRM1/VRM2

Control:
Adjusts sensitivity.
Switch:
Temporarily erases heading
line (and north mark if displayed).

Control:
Reduces sea clutter.
Switch*:
(Long press) Shifts your vessel`s
position to cursor location.
(Brief press) Doubles size of
area between your vessel and
location selected by cursor.

Control:
Reduces rain clutter.
Switch*:
Displaces the EBL origin.

MENU

EBL/VRM

SELECT

GAIN

HM-OFF

A/C SEA

F1

A/

C RAIN

F2

GUARD

+

EBL/VRM

CONTROL

TLL

A/C AU

TO

BRILL

ST BY

TX

Sets guard zone area.

Sets radar range.

Enables/erases
EBL1/EBL2/EBL3/EBL4.

Outputs target position data.

Automatically reduces sea and
rain clutters.

Adjusts display brilliance.

Sets radar in stand-by;
transmits radar pulse.

Turns power on/off.

*Default switch function.

Figure 2-1 Control panel

9

2.2 Display Indication and Markers

RANGE RING

PI LINE

Range

36

Range ring interval

Pulselength

Display mode

GUARD ZONE 1

EBL1

VRM1

VRM2

EBL2

NM

6
LP
HU

300

270

240

22 45.135 N

21.237 E

115

99.9NM 360

000

330

30.0V

210

Off center

Zoom

030

150

VRM1 VRM2

15.8NM

EBL1 EBL2

281 K

AUTO

OFF-CENT

ZOOM

060

090

120

31.8NM

180 K

Tuning indicator

Interference rejector

IR

OFF

TRAIL

OFF

OWN SHIP

HDG 270

COG 255 T

WAYPOINT

22

45.135 N

21.237 E

115

GUARD ZONE 1

Off

MARKERS

VRM1 25.0 NM

EBL1 138 K

CURSOR R/B

RANGE:

ARP VESSEL

VESSEL A

SOG 15.0KT
RNG 130.0NM
CPA 10.1NM

AIS VESSEL

VESSEL 1

SPD 12.0KT
RNG 20.0NM
CPA 9.1NM

ES

OFF

A/C Auto

OFF

X-band

SOG 03.5KT

TTG

**.**

GUARD ZONE 2

1.02~2.10NM
IN (or OUT)

VRM1 10.9 NM

EBL2 152 K

BEARING:

Safe

COG 270 M
BRG 99

M

TCPA 10:20:30

Safe

CRS 128M
BRG 99

M

TCPA 24:30:30

Echo Stretch

A/C Auto

GUARD ZONE 2

VRM2 range

Figure 2-2 Display indications

EBL2 range
EBL1 range

VRM1 range

10

2.3 Turning the Radar On/Off

Press the [POWER] key to turn the radar on or off.
The control panel lights and a timer displays the time remaining for warm up of
the magnetron (the device which produces radar pulses), counting down from 1:30
to 0:01.

2.4 Transmitting

After the power is turned on and the magnetron has warmed up, STAND-BY
appears at the screen center. This means the radar is now fully operational. In
stand-by the radar is available for use at anytime - but no radar waves are being
transmitted. Press the [ST-BY/TX] key to transmit. When transmitting, any echoes
from targets appear on the display. This radar displays echoes in eight tones of
green according to echo strength.

2.5 Echo area

The echo display area for the B, C and W types is available in three configurations:
round, wide, and full screen. You can select a configuration with 7 ECHO AREA
on the ECHO menu.

Round Wide Full

2.6 Reference Position

The reference position for measurements (range, bearing, etc.) and markers (heading
line, stern mark, etc.) can be antenna position or consistent common reference point
(CCRP), which is a location on own ship to which all horizontal measurements, for
example range, bearing, relative course, relative speed, closest point of approach
(CPA) or time to closest point of approach (TCPA), are normally referenced.

To select reference position, press the [MENU] key to enter the Main Menu, select

Reference Point and press [ACQ/ENTER] key, in the pop-up window select

""
""" "ANT or CCRP and press [ACQ/ENTER] key.

The position of the own ship marker changes according to reference position as
shown below. If the CCRP is positioned outside of the effective display area, the

bearing scale is indicated with the appropriate reduced detail.

11

Radar antenna
position is at
center of display

ANT position CCRP position

Conning position is at
center of display

Range and bearing are measured and graphics are drawn according to reference
position as in the table below.

Marks, measurements and reference point

Category Item

EBL

Range and bearing
measurement

Graphics

Bearing cursor

Course, speed

VRM
Cursor

PI line

Range ring

Heading line

Stern mark
Beam line

Own ship vector

Own ship track

Reference point
CCRP Antenna position

Range and bearing
measured from CCRP

Drawn from CCRP

Drawn with CCRP at
center

Calculated with CCRP
at center

Range and bearing
measured from antenna
position

Drawn from antenna
position

Drawn with antenna
position at center

Calculated with antenna
position at center

CPA,TCPA

BCR, BCT

Own ship data

Heading
Speed

Course over ground

Speed over ground

Own L/L

Calculated with CCRP
at center

Calculated from bow position

Data from sensor, regardless of reference
point selected

Calculated with antenna
position at center

12

2.7 Own Ship Marker

Own ship marker ( ) may be inscribed on the screen as below.

1. Go to Installation setup menu;

2. Select the Own Ship Shape and press [ACQ/ENTER] key;

3. Select the Draw and press [ACQ/ENTER] key;

4. Drawing interface pops up on the screen as follows:

""

""
""

01

10

09

08

07

02

03

04

05

06

2.8 Stand-by

When you won't be using the radar for an extended period, but you want to keep
it in a state of readiness, place it in stand-by by pressing the [ST-BY/TX] key.
The display shows "STAND-BY," navigtion data, or goes into the economy
mode depending on menu setting. (More on menu operation later.)

Economy mode

The LCD display

to reduce power consumption. This feature is called the "economy mode."
Power consumption in the economy mode is 28W. When economy mode is no,

he lamp next to the [POWER] key lights.

Navigation data display during stand-byor AIS data

If a navigation aid inputs navigation data to this radar, navigation data can be
displayed during stand-by. You can turn the navigation data display on/off
through the menu. Figure 2-3 shows a typical navigation data display during
standby. Similarly, if the AIS data input case , AIS data can be display during
Stand-by.

can be set to automatically turn itself off when in stand-by,

Note 1:Availability of a particular display item depends on incoming data.
Note 2:When Range to Waypoint reaches 0.1nm, the WPT mark jumps to dead
ahead even though a difference may exist between heading and BRG to WPT.
Note 3:When cross track error exceeds 1 nm on either side, the XTE mark

starts blinking.

13

Speed

Depth

To Waypoint
bearing heading

Time-to-go to

TO Waypoint

Bearing TO Waypoint

Range to TO Waypoint

SPEED

DEPTH

Heading

N

L XTE

10.5

125

TRIP

Kt

TEMPERATURE

m

E

HDG

092.5

180.0 M

CRS

TTG

WPT
BRG 45.0 M
RNG 12.0NM

OWN SHIP

LAT 30 00 . 00N
LON 135 00.00E

XTE

R 0.3NM

W

000.3nm

+17.3

01:08

ST-BY

Time-to-go to Stand-by

Trip distance since power on

Course

S

Ship s position in

'

latitude and longitude

Cross Track Error
Mark

XTE R

direction and amount
of error.

" " shows

1.0 1.0

0.5 0.5

Figure 2-3 Typical navigation data display
during stand-by

2.9 Selecting the Range

The range selected automatically determines the range ring interval, the number
of range rings, pulselength and pulse repetition rate, for optimal detection
capability in short to long ranges. You can select which ranges and pulselength
(for 1 mile range) to use through the menu. The range, range ring interval and
pulselength appear at the botton left-hand corner of the display.

To select a range;

When navigating in or around crowded harbors, select a short range to watch for

possi ble collision situations.

If you select a lower range while on open water, increase the range occasionally

to watch for vessels that may be heading your way.

2.10 Adjusting Picture Brilliance

The [BRILL] key adjusts the brilliance of the radar picture in eight levels.
Press the [BRILL] key to set the brilliance level.
The current level momentarily appears on the screen.

14

2.11 Setup display color

In order to adapt to the different environments, the radar echo display the back­ground color and echo color can be set by users themselves, there are five kinds
of background colors and three kinds of echo colors available. Setting methods are
as follows:

1.By menu

1) Press [FUNCTION] key open main menu;

2) Select ''OTHER MENU'' and press [ACQ/ENTER] key;

3) Press [ ]or [ ] key select ''Color setting'' & press [ACQ/ENTER] key
open the color setup menu;

4) Press [ ] or [ ] key select ''Background Color'' or ''Echo Color'' press
[ACQ/ENTER] key;

5) Press [ ] or [ ] select color desired and press [ACQ/ENTER] key;

6) Press [MENU] key to close the menu.

2.Using the function key
The function keys [F1] function default setting for ''Background Color'' ,[F2]
key default setting for ''Echo Color''. Directly on the keyboard you can press
these two keys select the desired color setting.

2.12 Adjusting Receiver Sensitivity

The [GAIN] control adjusts the sensitivity of the receiver. It works in precisely
the same manner as the volume control of a broadcast receiver, amplifying the
signals received. The proper setting is such that the background noise is just
visible on the screen. If you set up for too little sensitivity, weak echoes may
be missed. On the other hand excessive sensitivity yields too much background
noise; strong targets may be missed because of the poor contrast between desired
echoes and the background noise on the display. To adjust receiver sensitivity,
transmit on long range, and adjust the [GAIN] control so background noise is

just visible on the screen.

15

2.13 Adjusting the A/C SEA Control (reducing sea clutter)

Echoes from waves can be troublesome, covering the central part of the display
with random signals known as "sea clutter." The higher the waves, and the higher
the scanner above the water, the further the clutter will extend. Sea clutter appears
on the display as many small echoes which might affect radar performance. (See
the Figure 2-4.) When sea clutter masks the picture, adjust the A/C SEA control to

reduce the clutter.

How the A/C SEA control works

The [A/C SEA] control reduces the amplification of echoes at short ranges (where
clutter is the greatest) and progressively increases amplification will be normal at

those ranges where there is no sea clutter.

Adjusting the A/C SEA control

The proper setting of the A/C SEA should be such that the clutter is broken
up into small dots, and small targets become distinguishable. If the control is set
Too low, targets will be hidden in the clutter, while if it is set too high, both sea
clutter and targets will disappear from the display. In most cases adjust the con­trol until clutter has disappeared to leeward, but a little is still visible windward.

1. Confirm that the sensitivity is properly adjusted, and then transmit on short
range.

2. Adjust the [A/C SEA] control so small targets are distinguishable but some

clutter remains on the display.

Sea clutter at
display center

Figure 2-4 How to adjust the STC control

A/C SEA control adjusted;
sea clutter suppressed.

16

Tip for adjusting the A/C SEA

A common mistake is to over-adjust the circuit so all the clutter is removed. As
an example set up for maximum STC. You will see how the center of the display
becomes dark. This dark zone can be dangerous (targets may be missed),
especially if the sensitivity is not properly adjusted. Always leave a little clutter
visible on the display to be sure weak echoes will not be suppressed. If there is

no clutter visible on the display, turn off the circuit.

2.14 Apply the A/C RAIN (reducing rain clutter)

The vertical beamwidth of the antenna is designed to see surface targets even
when the ship is rolling. However, by this design the unit will also detect rain
clutter (rain, snow, hail, etc.) in the same manner as normal targets. Figure 2-5

Shows the appearance of rain clutter on the Display.

Adjusting A/C RAIN

When rain clutter masks echoes, adjust the [A/C RAIN] Control, This control spl­its up these unwanted echoes into a speckled pattem, making recognition of solid
targets easier.

Appearance of rain clutter

A/C RAIN control adjusted;
rain clutter suppressed.

Figure 2-5 Effect of A/C RAIN

Note: In addition to reducing clutter, the [A/C RAIN] control can be used in fine
weather to clarify the picture when navigating in confined waters. However, with
the circuit activated the receiver is less sensitive. Therefore, turn off the circuit

when its function is not used.

17

Automatic adjustments of A/C SEA and A/C RAIN

Push the [A/C Auto] key. "A/C Auto" at the bottom left-hand corner of
the display when the A/C AUTO circuit is on. You can fine tune by adjusting the
[A/C SEA], [A/C RAIN] and [GAIN] controls.

appears

2.15 Erasing the Heading Line

The heading line may occasionally mask a target. To view the target, you can
temporarily erase the heading line by pressing and holding down the [GAIN (HM
OFF)] control. Release the control to re-display the marks.

Heading
Line

Figure 2-6 Heading line

2.16 Measuring the Range

You can measure the range to a target three ways: by the range rings, by the
cursor, and by the VRM (Variable Range Marker).

By range ring

Count the number of rings between the center of the display and the target.
Check the range ring interval and judge the distance of the echo from the echo
from the inner edge of the nearest ring.

By cursor

Operate the omnipad to place the cursor intersection on the inside edge of the
target echo, The range to the target, as well as the bearing, appears at the
bottom right-hand corner of the display.

18

By VRM

1. Press the [EBL/VRM SELECT] key to circumscribe a VRM readout (at the
bottom center).Each press of the key selects the readout of EBL1,EBL2,VRM1
or VRM2 in that order.

VRM1 VRM2

EBL1 EBL2

25.0NM

138 R

10.9NM

152 R

Figure 2-7 Display bottom, showing location
of EBL and VRM readouts

2. Press the [EBL/VRM CONTROL] key enable control of the VRM by the
omnipad.

3. Operate the omnipad to place the outside edge of the VRM on the inside
edge of the target.

4. Check the VRM readout at the bottom right-hand corner of the display to
find the range to the target.

5. To anchor the VRM, press the [EBL/VRM CONTROL] key.

6. To erase the VRM, press and hold down the [EBL/VRM CONTROL] key
about two seconds.

Range

Range ring

Interval

6.0 NM

2.0

VRM1

VRM2

VRM1 Range

VRM2 Range

2NM

152 R

Cursor range

Target

Cursor

22 45.135 N

21.237 E

115

3.5NM 300

VRM1 VRM2

4NM

EBL1 EBL2

138 R

Figure 2-8 Measuring range by the cursor,
range rings and VRM

Note: You can display the range readout of the VRM and cursor in nautical
miles, statute miles or kilometers. For details see the next chapter

19

2.17 Measuring the Bearing

There are two ways to measure the bearing to a target: by the cursor, and by
the EBL (Electronic Bearing Line).

By cursor

Operate the omnipad to bisect the target with the cursor intersection. The bearing
to the target appears at the bottom of the display.

By EBL

1. Press the [ERL/VRM] key to an EBL readout (at the bottom

display

left-hand corner). Each press of the key selects the readout of EBL1, EBL2,

VRM1 or VRM2 in that order.

2. Press the [EBL/VRM CONTROL] key to enable control of the omnipad.

3. Operate the omnipad to bisect the target with the EBL.

4. Check the EBL readout at the bottom left-hand corner of the display to find
the bearing to the target.

5. To anchor the EBL, press the [EBL/VRM CONTROL] key.

6. To erase the EBL and its readout; press and hold down the [EBL/VRM
CONTROL] key about two seconds.

Target

Cursor

EBL1

EBL2

Cursor Bearing

22 45.135 N

115

3.5NM 45

21.237 E

VRM1 VRM2

4NM

EBL1 EBL2

40 R

EBL1 Bearing

EBL2 Bearing

2NM

160 R

Figure 2-9 How to measure bearing by EBL and cursor

Note: The bearing readout for the EBL and the cursor can be display in relative
or true bearing (true bearing requires heading sensor input) For north up and
course up display modes the bearing reference is always true. For details see
the next chapter.

20

Tips for measuring bearing

Bearing measurements of smaller targets are more accurate; the center of

larger target pips is not as easily identified.

Bearings of stationary or slower moving targets are more accurate than

Bearings of faster moving targets.
To minimize bearing errors keep echoes in the outer half of the picture by
changing the range scale; angular difference becomes difficult to resolve as

a target approaches the center of the display.

2.18 Using the Offset EBL

The offset EBL provides two functions: predict collision course of radar target and
measure the range and the bearing between two targets.
Predicting collision course

1. Press the omnipad to place the cursor on the center of the target.

2. Press the [EBL/VRM SELECT] key to choose EBL1 readout and then press
the [EBL/VRM CONTROL] key.

3. Select on the menu and press the [ACQ/ENTER] key.

4.

Press [ ] or [ ] key select "ON" and press [ACQ/ENTER] key.

EBL OFFSET

5. Press the [EBL/VRM CONTROL] key.

6. Operate EBL1 so it passes through the center of the target.
If the target tracks along the EBL towards the center of the display (you vessel's

Position), the target may be on a collision course.
To cancel, select SHIFT and press the [ACQ/ENTER] key. Press [ ] or [ ]
key select "OFF" and press [ACQ/ENTER] key.

36

Target moved

Here.

EBL1 origin
(Initial position
of target)

VRM1

Offset EBL
(EBL1)

LP
HU

270

NM

6

300

330

000

30.0V

030

060

090

240

22 45.135 N

21.237 E

115

13NM 90

210

150

EBL2

120

VRM1 VRM2

6.1NM

EBL1 EBL2

138 R

Figure 2-10 Predicting collision course by

using the offset EBL

21

32NM

152 R

Measuring range and bearing between two targets

The procedure which follows shows how to measure the range and bearing between
target

1. Press the omnipad to place EBL1 "A".

"A" and target "B" in Figure 2-11.

's origin (cursor) on the center of target

2. Press the [EBL/VRM SELECT] key to choose EBL1 readout and then press
the [EBL/VRM CONTROL] key.

3. Select EBL OFFSET on the menu and press the [ACQ/ENTER] key. EBL1

's

origin shifts to cursor.

4. Press the [EBL/VRM CONTROL] key.

5. Press the onmipad to bisect target

"B" with EBL1. Check the EBL1 readout to

find the bearing between target "A" and target "B".

6. Press the [EBL/VRM SELECT] key to choose VRM1 readout. Press the
omnipad to place the outside edge of VRM1 on the inside edge of target "B".
Check the VRM1 readout to find the range between target "A" and target "B".

7. To cancel, select EBL OFFSET on the menu and press the [ACQ/ENTER] key.

EBL1

VRM1

Cursor Bearing

115

5.5NM 20

22 45.135 N

21.237 E

VRM1 VRM2

4NM

EBL1 EBL2

70 R

VRM1 Range

VRM2 Range

2NM

152 R

Figure 2-11 Measuring the range and bearing
between two targets by using the offset EBL

22

2.19 Shifting (off centering) the Picture

Your vessel's position can be shifted up to 75% (not available on 48nm range)
of the range in use to view the situation around your vessel without changing
the range or size of targets.

1. Press the omnipad to set cursor where desired.

2. Press the [MENU] key ,select "SHIFT" and press [ACQ ENTER] key;

3. Press [ ] or [ ] key select "ON" and press [ACQ/ENTER] key.
"

OFF-CENT" appears at the top right corner of the display when the picture
is shifted.

Cursor

Place cursor Where desired

Press [OFF CENTER] key to off center

display

Cursor

Figure 2-12 Shifting the picture

Cancelling shifted picture

Repeat the above steps and select "OFF"

2.20 Zoom

The zoom feature allows you to double the size of the area between your vessel
and any location within the current range to take a closer look at an area of interest.

1. Select location with the cursor.

2. Select ZOOM on the menu, ZOOM appears at the top right corner when the
ZOOM function is on .

23

Cursor

Cursor

Place cursor Where desired

Press [ZOOM] key to zoom

Figure 2-13 Zoom Function

Note1: Zoom is cancelled when range or presentation mode is changed.

Cancelling Zoom

Repeat the above steps and select "OFF"

2.21 Outputting Target Position

Target position data can be output to the navaid in format. Press and
hold down the [TLL] key to output the data. This function requires position data
and heading signal.

IEC61162

24

3. MENU OPERATION

3.1 Basic Menu Operation

The menu mostly contains less-often used functions which once preset do not
require regular adjustment. To open or close the menu, press the [MENU] key.
You can select items on the menu with the omnipad.

1. Press the [MENU] key to display the main menu.

Figure 3-1 Main menu

2. Press the omnipad to select the item. For example, select RINGS. A message
appears at the of the menu window.

3. Press the key to select setting below.

right

[ ] or [ ]

Figure 3-2 Messages for RING menu

4. Press the [MENU] key to close the menu.

25

3.2 Selecting the presentation mode

This radar provides four presentation modes. Head-up, course-up, north-up and

.true motion

1. Press the [MENU] key.

2. Operate the omnipad to select "MODE".

3. Press the [ACQ/ENTER] key.
With heading sensor connection the display and the display and the display mode
indication at the top lefthand corner of the display.

want mode and press [ACQ/ENTER] key.

the display mode is always HU.

4. Press the [MENU] key to close the menu.
Note: The radar begins operation with last selected display mode (except course
up) whenever the unit is turned on. Note however that head up is selected when
course up was the last used mode.

Head up

The picture is oriented so the heading line is at the top of the display. This mode
is useful for navigation in congested waters.

Course up

The course up mode shows heading by the heading line, at the top of the
display. To get heading desired, steer vessel in direction desired, and the show
CU at the top lefthand corner of the display.

"

North up

North is at the top of the display and the heading line moves with
This mode is useful for determining ship s position and as a navigation monitor on

Ship's

If there is no heading sensor connection,

'

Press [ ] or [ ] key select

"

Ship's

heading.

a nautical chart. The picture is stabilized against yaw of vessel, thereby reducing
of target echoes.

True motion

True motion displays own ship and moving objects in their true motion.

3.3 Magnifying long range echoes (echo stretch)

Normally, the reflected echoes from long range target appear on the display as
weaker and smaller blips even though they are compensated by the radar's internal

circuitry. The echo stretch function magnifies these small blips in all ranges. Two
types of echo stretch are available: ES1 which stretches echoes in bearing direction
and ES2 which stretches them in both range and bearing directions.
To turn the echo stretch on or off;

1. Press the [MENU] key to open the menu.

2. Select ECHO STRETCH .

3. Press the [ACQ/ENTER] key.

4. Press [ ] or [ ] Key select ES1,ES2 or Off.

""

26

Bearing
direction

Bearing
direction

Range
direction

Echo stretch 1

Echo stretch 2

Figure 3-3 Echo stretch

Note: This function magnifies not only targets but also sea clutter and radar
interference. For this reason be sure the controls for adjustment of sea clutter and
radar interference are properly adjusted before activating the echo stretch.
Note: ES2 is not available on Short Range.

3.4 Echo Trail

You can show the movement of all radar targets relative to your vessel in afterglow
vessel in afterglow. This function is useful for alerting you to possible collision
situations.

Starting echo trail

1. Press the [MENU] key to open the menu.

2. Select "ECHO TRAIL"by the omnipad.

3. Select "On by pressing the [ACQ/ENTER] key."

Figure 3-4 How the echo trail feature work

TRAIL, the echo trail time selected (on MENU") and elapsed time

"VIDEO
appear at the top right-hand corner of the display. Then, afterglow starts extending
from all target.
Note: Trails are restarted when range or mode is changed or zoom or shift is turn­ed on.

27

Fixed time trail

1. When the elapsed time clock counts up to the trail time selected, the elapsed
time display freezes.

2. The oldest portions of trails are erased so only the latest trail, equal in length
to the trail time selected, is shown.

3. Trail continues.
For example, the one minute trail time is selected. When the elapsed time clock
counts up to 60 seconds, the elapsed time clock counts up to 60 seconds, the
elapsed time display freezes at “60,"but the latest one minute of trail are erased
and then trail continuous.

Continuous trail

The maximum continuous trail time is 99 minutes and 59 seconds. When the
elapsed time clock counts up to that time the elapsed time display is reset to zero
and trail begins again.

Cancelling echo trail

Select "OFF(deactivate)" at "ECHO TRAIL" on the menu.

Changing trail attributes

Trail gradation and trail time can be selected on the OTHERS menu.

Item In

OTHERS
menu

Trail Tone

Trail Time

Trails can be shown in single
or multiple gradations.
Multiple paints trails getting
thinner with time just like the
afterglow on an analog PPI
radar.

Trail time can be set for 15sec,
30sec, 1min, 3min, 6min,
15min, 30min or continuous.

Description

Single

Table 3-1 Trailing attributes

Multiple

3.5 Suppressing Radar Interference

Radar interference may occur when near another shipborne radar operating in the
same frequency hand as you radar. Its on-sereen appearance is many bright dots
either scattered at random or in the form of dotted lines extending from the center
to the edge of the display. Figure 3-6 illustrates interference in the from of curved
spokes. Interference effects are distinguishable from normal echoes because they
do not appear in the same place on successive rotations of the antenna.

28

Figure 3-6 Radar interference

Four levels of interference are available, including off; I 1, I 2, IR3 and OFF,IR3
provides the highest level of rejection.

1. Press the [MENU] key.

2. Select "VIDEO MENU"and press the [ACQ/ENTER] key.

3. Select "Int Reject".

4. Select level desired by operation the omnipad.

5. Press the [ACQ/ENTER] key.

6. Press the [MENU] key to close the menu.

RR

Figure 3-7 VIDEO MENU

3.6 Selecting

Pulse length pulse
length

resolution are reduced.

the greater the direction range capability, however range accuracy and range

Pulse Length

is the transmission time of a Single radar pulse. The longer the

29

3.7 Guard Alarm

The guard alarm allows the operator to set the desired range and bearing for a
guard zone. When ships, islands, landmasses, etc. Violate the guard zone an audible
alarm sounds and the offending target brinks to call the operator's attention.

Selection of guard zone type

The guard alarm can be set to sound when a target either enters or exits the guard
zone. You can select which type of guard alarm you want through the menu.

In alarm

The alarm sounds on targets entering the guard zone. "IN" appears in the guard
zone data field , the guard zone will flash display.

Out alarm

The alarm sounds on targets exiting the guard zone. "OUT" appears in the guard
zone data field , the guard zone will flash display.

Dashed line
no alarm

Guard

IN ALARM

OUT ALARM

Figure 3-8 In and Out alarm

Setting a guard zone

Preparation

1. Press the [MENU] key, and the select MENU"and pressing the
[ACQ/ENTER] key.

2. Select "Guard Mode" and "In" (alarm on target entering zone) or "Out" (alarm
on target exiting zone) by operating the omnipad.

3. Press the [ACQ/ENTER] key.

4. Press the [MENU] key to close the menu.

"FUNCTION

To set a guard zone

1. Mentally create the guard zone you want to set.

2. Operate the onipad to set the cursor on point A or B. Press the [ ]
key. See Figure 3-9

3. Operate the omnipad to set the cursor on point C or D. See Figure 3-9 (3).

4. Press the [ ] key.

screen

ACQ/ENTER Alarm zone set, the red dotted line appears on the

See Figure 3-9 (4).

30

ACQ/ENTER

A

Asterisk blinking

Guard zone to set

GIN

Drag cursor here.

1 Mentally create the

guard zone to set.

GIN GIN

4 Guard zone completed.

Figure 3-9 How to set the guard zone

2 Drag cursor to top left corner of

zone and press [GUARD].

Guard zone

3 Drag cursor to bottom right corner of zone

and press [GUARD].

31

3.8 Watchman

The watchman function periodically transmits the radar for minute to check for
targets in a guard zone. If it finds change in the zone from the previous
transmission it sounds the radar continuously. This feature is useful when you do
not need the radar's function continuously but want to be alerted to radar targets

in a specific area.

TX St-by TX St-by

1min

Watchman starts.

5 10 or 20
min

1 min

5,10 or 20
min

Figure 3-10 How watchman works

How watchman works

When the time selected for the watchman restperiod has elapsed, the radar autom­atically transmits for one minute to check the condition inside the guard zone. If

"

there is no change, the radar goes into stand-by ( " appears during
stand-by.) If there is change, the radar sounds the audible alarm, cancels the watc­hman function and transmits continuously.
Turning on watchman

1. Create a guard zone (usually 360 degrees) with the guard alarm function.

2. Press the [MENU] key.
"

3. Select MENU".

FUNCTION

4. Press the [ACQ/ENTER] key.

WATCHMAN

5. Select "Watchman".

6. Press the omnipad to select watchman rest period; 5 minutes, 10 minutes or 20

minutes.
"WATCHMAN"appears at the top of the screen, the radar transmits for one minute
to check for targets inside the guard zone. And the the shuts off and

LCD display

the radar goes into stand-by.

Cancelling watchman

Go into the " menu, and set "Watchman" for off.
Note 1: Watchman can be used without a guard zone.
Note 2: The alarm sounds just before the radar starts and stops transmitting.

"

FUNCTION

32

3.9 Displaying Navigation Data

Navigation data can be displayed in the data boxes if this radar receives navigation
input in format. Navigation data include.

IEC 61162

position in latitude and longitude
range, bearing and time-to-go to both waypoint selected on the navigator and

the cursor.

speed.

(If the navigation input includes destination data, waypoint position is denoted on
the radar display by a dashed ring.)
To turn navigation data on or off;

1. Press the [MENU] key.

2. Select the " ".

DATA FIELD

3. Press the [ACQ/ENTER] key.

4. Press the [ACQ/ENTER] key to select the message for Navigation display.

For example:OWN SHIP , POSITION or WAYPOINT etc.

5. Prss the [ACQ/ENTER] key to set.

6. Press the [MENU] key to close the menu.

36

NM

6
LP
HU

300

270

240

22 45.135 N

21.237 E

115

99.9NM 360

330

210

Waypoint Mark

000

030

150

138 K 152 K

VRM1 VRM2

EBL1 EBL2

25.0NM 10.9NM

AUTO

OFF-CENT

ZOOM

060

090

120

IR

OFF

TRAIL

OFF

OWN SHIP

HDG 270

COG 255 T

WAYPOINT

22

45.135 N

21.237 E

115

GUARD ZONE 1

Off

MARKERS

VRM1 25.0 NM

EBL1 138 K

CURSOR R/B

RANGE:

ARP VESSEL

VESSEL A

SOG 15.0KT
RNG 130.0NM
CPA 10.1NM

AIS VESSEL

VESSEL 1

SPD 12.0KT
RNG 20.0NM
CPA 9.1NM

ES

OFF

A/C Auto

OFF

X-band

SOG 03.5KT

TTG

**.**

GUARD ZONE 2

1.02~2.10NM
IN (or OUT)

VRM1 10.9 NM

EBL2 152 K

BEARING:

Safe

COG 270

M

BRG 99

M

TCPA 10:20:30

Safe

CRS 128 M
BRG 99

M

TCPA 24:30:30

Navigation
Data

Figure 3-11 Typical navigation data display

33

3.10 DescriptionFUNCTION MENU

Item

Panel Dimmer Select level of panel backlight.

Mark Brill Select brilliance of VRM, EBL, cursor,
guard zone and WP marks.

HD Mark Select brilliance of heading mark.

Characters Select brilliance of characters.

WPT Mark Select"On"to display the waypoint mark.

EBL Ref Select EBL reference for relative or true.
VRM Unit Select VRM unit

STBY Disp Select the display on stand-by; display "STBY"
or navigation data, or go into the economy mode.

Guard Mode Select condition which triggers guard alarm; in
or out.

Alm sense LV Select minimum echo strength which triggers
guard alarm.

Watchman Turn watchman on (set rest period) or off.
Color setting Set background color & Echo color

Speed Menu

Go to the speed menu.

Description

Range Select ranges in use.

Self Test Test keys, ROM and RAM, check antenna rotation
speed, and display program number

Installation Setup Go to the installation setup menu.

Table 3-2 MENU DescriptionFUNCTION

34

3.11 DescriptionVIDEO MENU

Trail Tone Select brillance of echo trails.
Int Reject Select level of interference rejection.
Pulselength Select pulselength for 1.5 and 3 mile ranges.
Trail Time Select the trail time.

Nosie Reject Select On to reject nosie. ""

Tune Select automatic or manual tuning.
To tune manually;
.Select "Manual by the omnipad.
.Press the [ENTER] key to enable manual tuning.
.While pressing and holding down the [GAIN]
control operate the omnipad.
MANUAL"appears at the top right-hand corner
when manual tuning is in effect.

D.Range Select the video signal sampling ranges.
Dead Sector Select On to display the dead sector.""

1"
2
3

"

Table 3-3 VIDEO MENU Description

3.12 Function Keys

The function keys (F1 and F2) work like the auto-dialing feature of a
telephone, automatically executing the function assigned to them. The function
can be turned off by pressing appropriate function key again.

Default settings

F1: Background Color
F2: Echo Color

How to register menu items

1. Press the [MENU] key.

2. Press [A/C SEA] (F1) or [A/C RAIN] (F2) to open the function menu.

Press [ ] or [ ] key select item, press [ ] or [ ] key page turning;

3. Select

function desired.

4. Press the [ACQ/ENTER] key.

35

5. Press the [MENU] key to close the menu.

Figure 3-12 Function menu

3.13 Suppressing Noise

Electrical noise can be suppressed by turning on "NOISE REJ" on the
menu.

VIDEO

3.14 Adjusting Brilliance of Markers

"Mark brill" on the menu adjusts the brilliance of markers such as the

cursor.

FUNCTION

36

4. FALSE ECHOES

Occasionally false echoes appear on the screen at positions where there is no
target. In some cases the effects can be reduced or eliminated. The operator
should familiarize himself or herself with the appearance and effects of these
false echoes, so as not to confuse them with echoes from legitimate contacts.

4.1 Multiple Echoes

Multiple echoes occur when a short range, strong echo is received from a ship,
bridge, or breakwater. A second, a third or more echoes may be observed on the
display at double, triple or other multiples of the actual range of the target as
shown in Figure 4-1. Multiple reflection echoes can be reduced and often removed
by decreasing the sensitivity or properly adjusting the A/C SEA.

True

Echo

Own ship

Multiple
echo

Figure 4-1 Multiple echoes

4.2 Side-lobe Echoes

Every time the antenna rotates, some radiation escapes on each side of the

beam called

side-lobes as well as the main-lobe, the side-lobe echoes may be represented on
both sides of the true echo at the same range, as shown in Figure 4-2. Side-lobes
show usually only at short ranges and from strong targets. They can be reduced
through careful reduction of the sensitivity or proper adjustment of the A/C SEA.

"side-lobes." If a target exists where it can be detected by the

37

Main-lobe

4.3 Indirect Echoes

True echo

Side-lobe

Sprious
target

Antenna

Figure 4-2 Side-lobe echoes

Indirect
path

Direct

path

Antenna

Target

Bridge

Indirect

path

Obstruction

(mast,funnel
etc.).

Direct

path

Own
ship

Target

True

echo

Heading

Iine

Indirect

echo

True

echo

Heading
Iine

Indirect

echo

Indirect

echo

Figure 4-3 Indirect echoes

38

Indirect echoes may be returned from either a passing ship or returned from a
reflecting surface on your own ship, for example, a stack. In both cases, the
echo will return from a legitimate contact to the antenna by the same indirect
path. The echo will appear on the same bearing of the reflected surface, but at
the same range as the direct echo. Figure 4-3 illustrates the effect of an indirect
echo. Indirect echoes may be recognized as follows :

they usually occur in a shadow sector
they appear on the bearing of the obstruction but at the range of the

legitimate contact

when plotted, their movements are usually abnormal, and
their shapes may indicate they are not direct echoes.

4.4 Blind and Shadow Sectors

Funnels, stacks, masts, or derricks in the path of antenna may reduce the
intensity of the radar beam. If the angle subtended at the antenna is more than
a few degrees a blind sector may be produced. Within the blind sector small
targets at close range may not be detected while larger targets at much greater
ranges may be detected. See Figure 4-4.

Vessel taller
than wharf

Wharf

Wharf

Blind sector
(no echo)

Mast, etc. In
path of radar
beam

Size of blind sector
depends on target
size and range.

Figure 4-4 Blind and shadow sectors

39

5. MAINTENANCE & TROUBLESHOOTING

This chapter tells you how to keep your radar in good working order. Before
reviewing this chapter please read the safety information which follows.

DANGER

Turn off the power before
performing any maintenance or
troubleshooting procedure.

Hazardous voltages can shock, burn or cause death.
Only qualified personnel totally famillier with electrical
circuits should work inside the units.

RF RADIATION HAZARD

Period

3 to 6
months

The radar antenna emits high frequency radio radiation
which can be harmful, particularly to your eyes. Never
look directly into the antenna from a distance of less
than two feet when the radar is in operation as you
could injure the cornea of your eyes. Always make
sure the radar is set to stand-by or is turned off before
starting work on the antenna unit.

Item

Exposed
nuts and
bolts on
antenna unit

Radome cover
(KR-1538)

Check point Remarks

Check for corroded or loosened
nuts and bolts. If necessary, clean
and repaint them thickly. Replace
them if heavily corroded.

Check for wear. Permanent
damage to the antenna's internal
circuitry will result if water leaks
into the radome.

Sealing compound may be used
instead of paint. Apply a small
amount of grease between nuts
and bolts for easy removal in future.

If a crack is found it should be
temporarily repaired by using a
samll amount of sealing compound
or adhesive. You should then
contact your dealer for service.

6 months
to 1 year

Display unit
connectors

Check for tight connection and
corrosion.

If corroded, contact your dealer
for replacement.

Table 5-1 Recommended maintenance program

40

5.1 Preventative Maintenance

Regular maintenance is important for good performance. Always keep the
equipment as free as possible from dirt, dust, and water splashes. Make sure
all screws securing the components are properly tightened. A maintenance
program should be established and should at least include the items listed in

table 5-1.

5.2 Replacing the Fuse

The fuse in the power cable protects the equipment against reverse polarity or
ship's mains, over current, and equipment fault. If the fuse blows, find the cause

before replacing it. Never use an incorrect fuse - serious damage to equipment
may result and void the warranty.
12 V : 10 A fuse
24/32 V : 5 A fuse

5.3 Troubleshooting

Table 5-2 contains simple troubleshooting procedures which you can follow to
try to restore normal operation. If you cannot restore normal operation, do not
attempt to check inside any unit of the radar system. Any repair work is best
left to a qualified technician.

5.4 Self Test

The self test facility checks the keyboard, ROM and RAM for proper operation.

1. Press the [MENU] key.

2. Select "FUNCTION MENU".

3. Select "Self Test" and press the [ACQ/ENTER] key. The following display
appears.

Figure 5-1 Self test screen

41

If... But... Then...

you pressed the
[POWER] key to
turn on the radar

the radar has warmed
up and you pressed
the [ST-BY/TX] key to
transmit

the control panel does
not light

nothing appears on the
display or display contrast
is poor

characters are distorted

the antenna does not
rotate

Characters and indications
are abnormal

try adjusting the control panel

backlighting on the Function menu.

battery may have discharged.
check fuse.

try adjusting the brilliance.

request service.

the problem may be in antenna

Unit request service.

have a qualified technician check

the set.

you have adjusted
the gain with A/C
RAIN and A/C SEA
off

neither noise nor targets
appear (indications and
markers do)

neither indications nor
markers appear (noise
and targets do)

the sweep (radial line
sweeping around the,display)
is not synchronized with
antenna rotation

there is no change in
sensitivity

check signal cable for damage.

have a qualified technician check
the set.

the pr oblem m ay be in th e an tenna
unit. Request service.

request service.

a key is pressed nothing happens

Table 5-2 Troubleshooting table

key may be faulty. Request service.

42

4. The ROM and RAM are automatically checked. If NG (No Good) appears to
the right of ROM or RAM indication, contact your dealer for advice.

5. To check the keyboard, press any key except the omnipad, ACQ and power keys.
Its corresponding location on the display lights in black if the key is operating
properly.

6. To escape from the test. Press the [MENU] key.

5.5 Life Expectancy of Magnetron

The following table shows the life expectancy of the magnetron.

Model

KR-1238/1538

KR-1268/1568

Type

MSF1421B

MAF1421B

MAF1422B

Code no.

V801

Life expectancy

2 000 - 3,000 hours
(Including stand-by)

Table 5-2 Life expectancy of magnetron

43

6. INSTALLATION

This chapter provides the procedures necessary for installation.
Installation mainly consists of the following:

sitting and mounting the display unit and antenna unit
connection of the signal cable and the power cable
establishing the ground
checking the installation, and
adjustments.

6.1 Antenna Unit Installation Sitting, handling considerations

The antenna unit is generally installed either on top of the wheelhouse or on
the radar mast on a suitable platform. Locate the antenna unit where there is
a good all-round view rigging intercepting the scanning beam. Any obstruction
will cause shadow and blind sectors. A mast for instance, with a diameter
considerably less than the width of the radiator, will cause only a small blind
sector, but a horizontal spreader or crosstrees in the same horizontal plane as
the antenna unit would be a much more serious obstruction; you would need
to place the antenna unit well above or below it.
It is rarely possible to place the antenna unit where a completely clear view
in all direction is available. Thus, you should determine the angular width
and relative bearing of any shadow sectors for their influence on the radar at
the first opportunity after fitting. (The method of determining blind and
shadow sectors appears later in this chapter.)
If you have a radio direction finder on your boat, local its antenna clear of
the antenna unit, to prevent interference to the direction finder. A separation
of more than two meters is recommended.
To lessen the chance of picking up electrical interference, avoid where
possible routing the signal cable near other onboard electrical equipment
Also avoid running the cable in parallel with power cables.
The compass safe distance should be observed to prevent deviation of the
magnetic compass.

Model

KR-1238/1538

Standard compass

1.3m 0.7m

44

Steering compass

Do not paint the radome (Model KR-1238/1538) or to ensure proper emission of
the radar waves.

When this radar is to be installed on larger vessels, consider the following

points:
(1) The signal cable run between the antenna and the display comes in lengths
of 10 m, 15 m, 20 m and 30 m. Whatever length is used it must be

unbroken; namely, no splicing allowed.

(2) Deposits and fumes from a funnel or other exhaust vent can adversely affect
the aerial performance and hot gases may distort the radiator portion. The
antenna unit must not be mounted where the temperature is more than 70 .

Mounting (KR-1238/1538)

ONWA

O

N

W

A

Figure 6-1 Typical antenna unit location

Unpacking the antenna unit

1. Open the antenna unit packing box carefully.

2. Unbolt the four bolts at the base of the radome to remove the radome cover.

Bolts

Radome cover

ONWA

Figure 6-2 Antenna unit

45

Mounting platform
Holes for antenna unit:

The mounting surface must be parallel with the waterline and provided with four
holes whose dimensions are shown in the outline drawing attached at the end of
this manual. The unit is adjusted so a target echo returned from the bow direction
will be shown on the zero degree (heading line) position on the screen. When
drilling holes, be sure they are parallel with the fore and aft line.

3. Prepare a platform of 5 to 10 millimeters in thickness for the antenna unit.

Find the cable entry on the radome base. Next, position the radome base so

the cable entry faces the stern direction. This alignment must be as accurate

as possible. Fasten the radome base to the mounting platform with four each

of M10 x 30 hex bolts, flat washers and spring washers.

SHIP'S BOW

CABLE
ENTRY

FLAT WASHER

SPRING WASHER

HEX BOLT

Effective
thread length

4- 12 HOLES

PLATFORM

Antenna base plate

Packing

Radome

5 -10 mm

Flat
washer

Spring
washer

Apply silicone sealant

Hex bolt

Platform

Figure 6-3 How to fasten the radome base to the mounting platform

46

Wiring and final preparation

Drill a hole of at least 20 millimeters diameter through the deck or bulkhead

4.

to run the signal cable between the antenna unit and display unit. (To

prevent electrical interference avoid running the signal cable near other

electrical equipment and in parallel with power cables.) Pass the cable through

the hole. Then, seal the hole with sealing compound for waterproofing

Remove the shield cover in the radome.

5.

Remove the cable clamping plate by unfastening four screws and removing

6.

a gasket.

Pass the cable through the hole at the bottom of the radome base.

7.

Secure the cable with the cable clamping plate and gasket. Ground the shield

8.

and vinyl wire by one of the screws of the cable clamping plate.

Motor

Connect the wire to the Video Processing unit.

9.
(1) 23-pin connector to P18

8-pin connector to P12()

P12P18

Figure 6-4 Location of P18/P12

47

Fix the shield cover. Do not pinch the cable.

11.
Loosely fasten the radome fixing bolts. You will tighten them after

12.
confirming the unit is working normally.

Mounting(KR-1568)

Figure 6-5 Typical antenna unit mounting locations

1. Drill four fixing bolt holes (13 millimeters dia.), One cable entry hole (approx.

50 millimeters dia.) In the mounting platform. See the outline drawing.

2. Detach the antenna housing cover from the antenna housing by loosening four

fixing blots. The antenna housing cover fitted with the transceiver module can
be stored in a convenient place until the wiring to the antenna unit is done.

3. Place the antenna bousing on the mounting platform and orient it as shown in

Figure 6-6.

SHip`s
bow

SHip`s
bow

Figure 6-6 How to orient the antenna unit

4. Insert four M12 60 hex head bolts with the seal washers from inside the

antenna housing, to prevent the bolts from contacting the transceiver module.
Install the seal washer with the larger diameter next to the head of the bolt.
Coat flat and spring washers and nuts and then use them to fasten the antenna
housing to the mounting platform. Finally, coat exposed parts of nuts, bolts and

Flat and spring washers as shown in Figure 6-7.

48

Note: Tighten the bolts by their nuts to prevent damage to the seal washer.
Do not turn the bolts to secure the antenna housing.

Hex head bolt

(M12 x 60)

Seal washer

Silicone
sealant

Scanner
housing

Figure 6-7 How to mount the antenna housing

Connections

Only the signal cable runs from the display unit to the antenna unit. Make the hole
for passing the cable through the bulkhead or deck at least 20 millimeters diameter.
In order to minimize the chance of picking up electrical interference, avoid where
possible routing the signal cable near other onboard electrical equipment. Also,
avoid running the cable in parallel with power cables. Pass the cable through the
hole and apply sealing compound around the hole for waterproofing.
The procedure for connecting the signal cable to the antenna unit is as following.

1. Through a pipe or waterproof cable grand fitted on the wheelhouse top or
bulkhead.

2. Unfasten of the scanner t to remove the cable gland

Fastening bolts at rear ail

assembly.

3. Pass the signal cable

sequentially through the fastening bolt , the washer ,
waterproof apron, under the washer ,and then through the mounting hole into
the base of the antenna inside (removed in step 2.)

FLAT WASHER

fastening bolt

BASE

waterproof apron

Figure 6-8 Passing the signal cable through the antenna housing

49

4. Fasten the cable

fastening bolts

5. Connect the lead wires to in the antenna housing by referring to

RD-AP-1568

the Interconnection Diagram. Fasten the ground washer at the bottom of the
antenna housing as shown in Figure 6-9.

Figure 6-9 Connection in the antenna housing

Final preparation

1. Place the antenna housing cover on the housing, Loosely fasten the four fixing
bolts on the cover.

Figure 6-10 Fastening the antenna housing cover

2. Apply grease to the two slot pins. Using a wooden hammer to prevent damage
to paint, insert slotted pins into the pinning holes until the pin head is flush
with the scanner housing surface.

Figure 6-11 How to insert slot pins

50

3. Now is the time to fix the radiator to the radiator bracket. Apply anticorrosive
sealant (silicone sealant) to hatched areas, to prevent corrosion. See the figure
below.Apply silicone sealant into threaded holes on the scanner radiator. Remove
the cap on the radiator bracket and orient the radiator bracket as shown in Figure
6-12. Apply grease to the O-ring and set it to the center of the radiator bracket.
Coat the radiator fixing bolts with silicone sealant. Fasten the radiator to the
radiator bracket with the ONWA logo on the radiator facing ship`s bow.

RA12

Figure 6-12 Fastening the radiator to the radiator bracket

4. Open the antenna housing cover and fix the stay as shown in Figure 6-13.

5. One end of the cable with and 8 way plugs has already been connected to

RD-AP-1568 Transceiver control signal

inside the scanner housing. with jacks

3-

J812 and J811 on the transceiver module, respectively. Connect the 7-way plug
to jack J801 on the MP Board. Secure the cable between and J801

RD-AP-1568

with the cable tie as shown in Figure 6-13.

Figure 6-13 Antenna unit, cover opened

51

6. Fasten the ground wire (black) of the signal cable to the chassis.

7. Loosely fasten the antenna housing cover. You will tighten the fixing bolts after
confirming the unit is working normally.

6.2 Display Unit Installation Mounting considerations

When selecting a mounting location for the display unit keep in mind the
following points.

Even though the display unit is waterproof, it is recommended that the display
unit must be mounted inside an enchosed cabinet.
Provide adequate space behind and around the unit to permit circulation of
air and to provide convenient access to the rear connectors.
Even though the picture is quite legible even in bright sunlight, keep the
display unit out of direct sunlight or at least shaded because of heat that can
build up inside the cabinet.
Locate the display unit in a position where you can view and operate it
conveniently but where there is no danger of salt or fresh water spray or

immersion.
The orientation of the display unit should be so the radar screen is viewed
while the operator is facing in the direction of the bow. This makes
determination of your position much easier.
Make sure you allow enough clearance both to get to the connectors behind
the unit and to allow you to get your hands 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 it can be pulled forward for
servicing or easy removal of the connectors.
The compass safe distance of 0.8 meters (standard compass) and 0.6 meters
(steering compass) should be observed to prevent deviation of the magnetic
compass.

Mounting

The display unit is designed to be mounted on a tabletop or bulkhead.

Using the hanger as a template, mark screw locations in the mounting location.

1.
Fix the hanger to the mounting location with five M6 tapping screws(supplied).

2.
Fit the knob bolts to the display unit. Install the display unit in the hanger.

3.
Tighten the knob bolts securely.

52

Connections

Connect the power cable to the power cable connector on the rear of the

1.
display unit.
Connect the signal cable to connector on the rear of the display unit.

2.
Run a ground wire (local supply) between the ground terminal on the rear

3.
of the display unit and the ship's superstructure.

Navigation aid, video sounder connection
If your navigation aid can output data in data format, your
vessel

's position in latitude and longitude, the range and bearing to waypoint,

IEC61162(NMEA0183)

speed and course may be input to this radar, and be seen on the screen.

Further if your video sounder can output depth in IEC 61162(NMEA 0183) data
format, depth can be displayed on the radar screen.

1. NMEA1 (5 pins connector)

PIN No.

1

2
3

4
5

Function

GND

3.3V

NMEA1 Input+
NMEA1 Input-

Not used

1

4

3

2

5

2. NMEA (6 pins connector)

PIN No.

1

2
3

4
5
6

Function
NMEA2+
NMEA2-

+12V

NMEA3+
NMEA3-

GND

1

5

6

2

4

3

3. VCA Now not used

4. UPGRAPE: Upgrade interface, you need to use special upgrade cable .

5. RS-422:

PIN No.

1
2

3

4

5

6

7

8

Function

GND

OUTPUT-

OUTPUT+

INPUT-

INPUT+

+12V
GND
+12V

1

7

6

5

2

8

3

4

53

Antenna

RS-422

Power

NMEA-2 Connector

NMEA-1 Connector

Figure 6-14 KR-1238/1268 Display connectors

Antenna

NMEA-2 Connector

RS-422

UPGRADE

Power

UPGRADE

FUSE

NMEA-1 Connector

VGA

VGA

Figure 6-15 KR-1538/1568 Display connectors

CAUTION

Ground the equipment.
Ungrounded equipment might
emit or receive electromagnetic
interference or cause electrical
shock

FUSE

CAUTION

Replace ther fuses to 5A for
24/32VDC operation

54

6.3 Exchange of Fuse for 24/32V Power Supply

The power cable comes with a 10A fuse in the fuse holder. This fuse is for use
with a 12V DC power supply. For 24V/32V DC power supply, replace the fuse
with the 5A fuse (supplied) to fuse holder.

6.4 Checking the Installation

After completing the installation, it is a good idea to recheck it to be sure all
steps were correctly done. Use the table 6-1 to check the installation.

Tick box (Table 6-1)

The signal cable is securely retained against the mast or mounting platform
and is free of interference from running rigging

The cable gland or entry on the deck, if provided, is waterproofed
The power connections to the battery are of correct polarity
The plugs at the rear of the display unit are tightly fastened
The fuse in the power cable is 10A (12V) or 5A (24V/32V DC)

6.5 Adjustments

This section covers adjustment of the radar after installation.

You will need to

adjust tune/video amplifier level input

enter antenna height

adjust tuning level

adjust sweep timing

adjust main bang suppression

setting a blanking area

These adjustment are done through the radar install menus.

Preparation

1. Turn off the radar. While pressing and holding down the [GAIN] control

press the [POWER] key.

2. Release [GAIN] control knob when you see "ONWA" logo and wait for finish

standby (finish count down).

3. Press the [MENU] key, and select "FUNCTION MENU" by using the

omnipad, and pressing [ACQ/ENTER] key.

4. Select "Installation setup".

Press the [ACQ/ENTER] key to open the installation setup menu.

55

.

.

Figure 6-16 Installation setup menu

Adjusting tune/video
Do the following to adjust tune and video amplifier level input.

1. Press the [ST BY/TX] key to transmit.

WARNING

Before transmitting the radar make sure no one is near
the antenna unit, to prevent the potential risk of being
struck by the rotation antenna and exposure to
radiation hazard.

2. On the Installation setup menu, select

"Tune/Video Adjustment" and press the

[ACQ/ENTER] key.

3. The unit automatically adjusts, displaying the following message.

[Tune/Video Auto Adjustment]

Now under correction.

Return to installation setup
menu after the correction.

Figure 6-16 Tune/Video Auto Adjustment messages

4. When adjustment is completed, the messages disappears.

56

Entering

STC range

1. Select

" " on the installation setup menu and press the [ACQ/ENTER]

STC Range

key.

2. Operate the omnipad to select

1 (about 6NM), 2 (about 4NM), 3 (about 3NM),

4 (about 2NM)

3. Press the [ACQ/ENTER] key.

Aligning heading (Adjustment sector:0~359.90)
You have mounted the antenna unit facing straight ahead in the direction of the
how. Therefore, a small but conspicuous target dead ahead visually should appear
on the heading line (zero degrees).

In practice, you will probably observe some small error on the display because of
the difficulty in achieving accurate initial positioning of the antenna unit. The foll­owing adjustment will compensate for this error.

1. Identify a suitable target (for example, ship or buoy) at a range between 0.125
to 0.25 nautical miles, preferably near the heading mark. To lessen error, keep
echoes in the outer half of the picture by changing the range. Aiso, be sure the
zoom and off center functions are off.

2. Select "Heading Alignment" on the installation setup menu and press the
[ACQ/ENTER] key. The following message appears on the display.

[ Heading alignment ]

Set EBL1 to center of target

dead ahead and press ENTER.

Correction 0.0

<Press MENU for inst setup>

Figure 6-17 Heading alignment message

3. Operate the omnipad to bisect target selected at step 1 with the heading line.

4. Press the [ACQ/ENTER] key.

5. As a final test, move the boat towards a small buoy and confirm that the buoy
shows up dead ahead on the radar when it is visually dead ahead.

57

Adjusting sweep timing(Adjustment range:0.000~4.266nm)

This adjustment ensures proper radar performance, especially on short ranges.
The radar measures the time required for a transmitted echo appears on the
display based on this time. Thus, at the instant the transmitter is fired, the
sweep should start from the center of the display (sometimes called sweep
origin.) A trigger pulse generated in the display unit goes to the antenna unit
through the signal cable to trigger the transmitter (magnetron). The time taken
by the signal to travel up to the antenna unit varies, depending largely on the
length of signal cable. During this period the display unit should wait before
starting the sweep. When the display unit is not adjusted correctly, the echoes
from a straight local object (for example, a harbor wall or straight pier) will
not appear with straight edges - namely, they will be seen as "pushed out" or
"pulled in" near the picture center. The range of objects will also be incorrectly

shown.

(1) Correct

(2) Target pushed
inward

(3) Target pushed
outward

Figure 6-18 Examples of improper and correct sweep timing

Transmit on the shortest range and confirm that the [GAIN] and [STC]

1.
controls are properly adjusted.
Visually select a target which forms straight line (harbor wall, straight pier).

2.

3.

Select

"Sweep Timing Adjustment" on the installation setup menu and

press the [ACQ/ENTER] key. The message appears.

[ Sweep Timing Adjustment ]

Use omnipad to staighten

Target and press ENTER key.

Correction 0.000 nm

<Press MENU for inst setup>

Figure 6-19 Sweep timing adjustment message

4. Operate the omnipad to straighten the target selected at step 2, and then press

the [ACQ/ENTER] key.

58

Adjusting MBS (Main Ban Suppression) (Adjustment: 0.00~0.25)
Main bang (black hole), which appears at the display center on short ranges, can
be suppressed as follows.

1. Transmit on long range about 10 minutes.

2. Adjust the gain to show a small amount of noise on the display.

3. Change to the 0.125 nautical mile range and adjust the [A/C SEA] control.

4. Select

"MBS adjustment" on the installation setup menu.

5. Press the [ACQ/ENTER] key. The following message appears.

[MBS Adjustment ]

Set value by omnipad
and press ENTER key

Correction 000

<Press MENU for inst setup>

Figure 6-20 MBS Adjustment message

6. Operate the omnipad to suppress main bang.(Left: low, right, between 0 and 25)

7. Press the [ACQ/ENTER] key.

Setting a blanking area
When the antenna is installed at a close distance in front of the wheelhouse, the
radar should be set not to transmit within that area. No echoes appear in the bla­nking areas.

1. Select "Dead Sector".

2. Press the [ENTER] key.

3. Operate the omnipad to enter staring point of area (in figures).

4. Press the [ENTER] key.

5. Operate the omnipad to enter ending point of area (in figures).

6. Press the [ENTER] key.

Area of not
ransmission

Figure 6-21 Blank areas where transmission is suspended

59

This area can be turned on/off on the MENU.

VIDEO

Note: This setting should be done after other adjustment are finished.

Magnetron heater voltage
Magnetron heater voltage is formed at the MOD Board of the antenna unit and
preadjusted at the factory for use with any length of signal cable. Therefore no
adjustment is required. However, verify heater voltage by following the procedure
below.

1. Turn on the radar(if it is not already on) and set it in stand-by.

2. Open the antenna housing (radome) cover. Connect a multitester, set to 10V DC

range.

Model Check point Rating Adjustment

Point

KR-1238/1538

Tp803

#4,#6

7.4~7.6V

R

V 801

on MD Borad

KR-1268/1568

Tp803

#4,#6

7.4~7.6V

R

V 801

on MD Borad

3. Close the antenna housing cover and tighten the fixing bolts.

60

7. ARPA

WARNING

This auto plotter is not designed to replace the human eye nor make decisions for the navig­ator. It is intended for use as an aid to navigation. Always maintain a watch while underway.
Data obtained from this auto plotter should always be double checked against other sources
to verify the reliability of the data.

This auto Plotter automatically tracks a acquired radar target and calculates its course and speed.
Indicating it by a vector, Since the data generated by this unit are based on what radar targets are
selected, the radar must always be optimally tuned for use with it to ensure that required targets
will not be lost or unwanted targets such as sea returns and noise will not be acquired and tracked.

A target echo does not always mean a landmass, reef, ships or other surface objects but can imply
returns from sea surface or precipitation. As the level of these returns varies with environment, the
operator is required to properly adjust the STC (ant-clutter sea), FTC (anti-clutter rain) and GAIN
controls to ensure that target echoes within the affected area are not eliminated from the radar screen.
The optimum settings of these controls may slightly differ between the normal radar operation and
plotting, and it is recommended to readjust them in accordance with the operating mode selected.

NOTICE

The installation must be done by a ONWA representative or suitably qualified radar technician.

Authorities require this.

Keep magnets and magnetic fields away from the equipment.

Magnetic fields will distort the picture and can cause equipment malfunction. Be sure the unit is well
away from equipment which gives off magnetic fields (speaker, power transformer, etc.).

The following items affect calculation accurary.

echo intensity
radar transmission pulsewidth
radar bearing error
gyrocompass error
own vessel or other vessel course change

Data for CPA, TCPA, ect. Are approximations only. Always use data obtained prudently.

61

Operation of ARPA

General

The Auto Plotter permits manual or automatic acquisition and automatic tracking
of up to 20 radar targets. An internal microprocessor calculates target data such as
speeds and courses and display the results in alphanumeric and by vectors. To
ensure the reliability of the displayed target data, the radar must be properly
adjusted for minimum sea returns and noise.

Principal Specifications

Acquisition and tracking:

Acquisition of up to 20 targets between 0.2 and 16 nm.

Automatic tracking of up to 20 acquired targets between 0.1 and 16 nm.
Vectors:
Vector length; 30s, 1,3,6,15,30 min.
Orientation; True velocity or relative velocity
Past positions: 5 past positions at intervals of 15,30s,1,2,3,6 min.
Alarm: Visual and audible alarms against targets violating CPA/TCPA limits,
Visual alarm against lost targets

Target discrimination: A target measuring about 800 m or more in the radial or
circumferential direction is regarded as a landmass and not acquired or tracked.
Echoes smaller than about 800 m are regarded as true targets.

Key Used Auto Plotter

The Auto plotter utilizes the following touchpad keys. Given below is a brief
description of these keys.

MENU: Display/Erase the main menu.

SELECT/CANCEL:

(Long press) Terminates plotting of the target selected with the cursor.
(Brief press) Displays the data of target selected with the cursor.

ACQ/ENTER: Acquires the target selected with the cursor.

62

ARPA MENU Operation

The ARPA MENU operation includes the followings;

Display: Turns on/off the plot symbols, past positions and target data.

All Cancel: Cancels the tracking of all targets.

Vector Ref: Selects relative vector or true vectors. To select your choice, open

the ARPA menu, and the legend Rel and True appear on the "3. Vector Ref"
line. Operate the omnipad. When your selection is in the reverse video, press the
[ACQ/ENTER] key.

Vector Length: Selects vector time.

History Selects past position plot interval.

:

CPA Set: Selects CPA alarm limit, When a target is predicted to come within

this limit, an aural alarm sounds and at the same time the corresponding target
symbol changes to a blinking triangle.

Note: If the preset CPA limit is set at OFF, a target which is on collision course
will not produce an alarm.

TCPA Set: Selects TCPA alarm limit.

Auto ACQ: Turns on/off Auto Acquisition Area.

Activating the Auto plotter

To activate the Auto Plotter, follow the steps shown below:

1. Adjust the GAIN, A/C SEA and A/C RAIN controls for proper radar picture.

2. Press the [MENU] key to open the main menu.

3. Operate the omnipad to select "ARP MENU".

4. Press the [ACQ/ENTER] key. The menu shown in Figure AP-1 appears.

5. Operate the omnipad to select the menu item "Display".

6. Operate the omnipad to select "On".

7. Press the [ACQ/ENTER] key.

8. Press the [MENU] key to close the menu.

63

Lost Target

Figure AP-1 ARP Menu

Target under auto tracking but not
selected for cursor data reading

36

LP
HU

270

NM

6

300

330

000

030

Target selected
for data reading

AUTO

IR

OFF

TRAIL

OFF-CENT

ZOOM

060

090

OFF

OWN SHIP

HDG 270

COG 255 T

WAYPOINT

22

45.135 N

21.237 E

115

ACQ ZONE 1

Off

MARKERS

VRM1 25.0 NM

EBL1 138 K

CURSOR R/B

RANGE:

ES

OFF

A/C Auto

OFF

X-band

SOG 03.5KT

TTG

**.**

ACQ ZONE 2

1.02~2.10NM
IN (or OUT)

VRM1 10.9 NM

EBL2 152 K

BEARING:

Auto
Acquisition
Area

240

22 45.135 N

21.237 E

115

99.9NM 360

120

210

150

VRM1 VRM2

15.8NM

EBL1 EBL2

281 K

31.8NM

180 K

Figure AP-2 ARPA Display

64

ARP VESSEL

VESSEL A

SOG 15.0KT
RNG 130.0NM
CPA 10.1NM

AIS VESSEL

VESSEL 1

SPD 12.0KT
RNG 20.0NM
CPA 9.1NM

Safe

COG 270 M
BRG 99

M

TCPA 10:20:30

Safe

CRS 128M
BRG 99

M

TCPA 24:30:30

Threatening
target

Deactivation the Auto Plotter

To deactivate the Auto Plotter.

1. Open the "ARP MENU".

2. Operate the omnipad to select the "Display".

3. Operate the omnipad to select "Off".

4. Press the [ACQ/ENTER] key.

5. Press the [MENU] key to close the menu.

Acquiring targets

Manual Acquisition

Follow the steps below to manually acquire a target. Up to 20 target can be man­ually acquired.

1. Place the cursor(+) on a target of interest by operating the omnipad.

2. Press the [ACQ/ENTER] key.

The plot symbol changes its shape according to the status as below. A vector
appears in about one minute after acquisition indicating the target s motion trend.
If the target is consistently detected for three minutes, the plot symbol changes to
a solid mark. If acquisition fails, the target symbol blinks ans disappears shortly.

CIRCLE (dotted)

Immediately after acquisition - Plot symbol shown in broken lines.

CIRCLE (dotted with a vector)

One minute after acquisition - Vector still unreliable.

'

CIRCLE(Soild with a vector)

3 minutes after acquisition - Plot symbol changes to a solid circel indicating
the stable tracking condition.

FRAME CIRCLE

The plot symbol of a target under tracking becomes twice as large as the nor­mal symbol when the target is selected for data reading.

Note 1: The target to be acquired should be within 0.2 to 16 nm from own
ship and not obscured by sea or rain clutter for successful acquisition.

Note 2: When you want to acquire 21th target, cancel tracking one of less im­portant target.

65

Note 3: When auto acquisition mode (Auto ACQ) is on, up to 5 target can be
acquired. For detail, see next section titled Automatic Acquisition.

WARNING

When a tracked target nears another tracked target the
targets may be "swapped."When two target come
close to each other, one of the two can become a "lost
targets."Should this happen, reacquisition of the "lost
target"is required after the two targets have separated.

Automatic Acquisition

The Auto plotter APRA can acquire up to 10 targets automatically by setting the
Auto Ac-quisition area predefined in the system. If Auto ACQ is selected after
more than 10 targets have been manually acquired, only the remaining capacity of
targets can be automatically acquired. Example; when 7 targets acquired manually,
then the Auto ACQ is switched on only 3 targets can be acquire automatically,
When ten targets have been automatically acquired, "AUTO TARGET FULL"
message appears at top left corner on the display.

Setting Auto Acquisition Area
Auto acquisition area is predefined between 2.0 and 2.5 nm in range and 45 on
either side of the heading line in bearing. If a target come into this area, it is
acquired automatically.

Figure AP-3 Auto acquisition area

Follow the steps shown below to activate the auto acquisition area;

1. Open the "ARP MENU".

2. Select "Auto ACQ" by operating the omnipad.

3. Operate the omnipad to select "On".

4. Press the [ACQ/ENTER] key.

5. Press the [MENU] key to close the menu.

66

Terminating Tracking of Targets

When the Auto Plotter has acquired 20 targets, no more acquisition occurs unless
targets are lost. Should this happen, cancel tracking of individual target or all
targets by the procedure described below.

Individual Targets

Place the cursor (+) on a target which you do not want to be tracked any longer
by operating the omnipad and press andgold down the [SELECT/CANCEL] key.

All Targets

All targets can be canceled from "ARPA MENU" at a time.

1. Open the "ARP MENU".

2. Select "All Cancel".

3. Press the [ACQ/ENTER] key.

Displaying Target Data

The Auto Plotter calculates motion trends (range, bearing, course, speed, CPA and
TCPA) of all targets under tracking at the ARP Data area.

CAUTION

At the speed under 5 kts the target data is
displayed with a delay because of the filtration

Place the cursor on a wanted target and press the [SELECT/CANCEL] key. Data
on the selected target is displayed at the bottom of the screen. The symbol of the
selected target gets . The data includes the
follows;

RNG/RBG (Range/Bearing): Range and bearing from own ship to the last-plotted
or selected target position with suffix "T"(Ture) or "M"(Magnetic). For ture
bearings suffix "T" is used in case of gyrocompass input and suffix M" is

Surrounded by a broken square frame

"

used in case of magnetic compass input.

67

COURSE/SPEED (Course/Speed):

Course and speed are displayed for the lastplotted or selected target with suffix
"T"(Ture) or "M"(Magnetic). For true bearings suffix "T"is used in case of gyroc­ompass input and suffix "M"is used in case of magnetic compass input.

CPA (Closest Point of Approach) is the closest range a target will approach to own
ship. Do not mix it with the operator preset CPA alarm limit.
TCPA is the time to CPA measured with present speeds of own ship and the targets.
Both CPA and TCPA are automatically calculated. When a target ship has passed
clear of own shop, the CPA is displayed and the TCPA appears as "**". TCPA
is counted up to 99.9 min. And beyond this it is indicated as TCPA>99.9 min.

Mode and length of Vectors

Ture or Relative Vector

Target vectors are displayed in relative or true mode. Own shop does not have a
vector in relative mode.

Vector Length

From the ARPA MENU, Vector Length can be set to 30 seconds,1,3,6,15 or 30
minutes and the selected vector time is indicated on the screen.

The vector tip shows an estimated position of the target after the selected vector
time elapses. It can be valuable to extend the vector length to evaluate the risk of
collision with any target.

Past position Display

The Auto Plotter displays equally time-spaced dots(maximum 5 dots) marking the
past positions of any targets being tracked.

If a target changes its speed, the spacing will be uneven. If it changes the course,
its plotted course will not be a straight line in TM mode.

Operational Warnings

There are two main situations which cause the Auto plotter to trigger visual and
audible alarms.

CPA/TCPA alarm
Lost target alarm

68

CPA/TCPA Alarm

Visual and audible alarm are generated when the predicted CPA and TCPA of any
target become less than their preset limits. The audible alarm continues for 10 se­conds.

The Auto plotter ARPA continuously monitors the predicted range at the Closest
Point of Approach (CPA) and predicted time to CPA(TCPA) of each tracked target
to own ship.

When the predicted CPA of any target becomes smaller than a preset CPA alarm
range and its predicted TCPA less than a preset TCPA alarm limit, the ARPA
releases an audible alarm. In addition, the target plot symbol changes to a triangle
and flashes together with its vector.

Provided that this feature is used correctly, it will help prevent the risk of collision
by alerting you to threatening targets, It is important that GAIN, A/C SEA, A/C
RAIN and other radar controls are properly adjusted and the Auto Plotter is set up
so that it can track targets effectively.

CPA/TCPA alarm ranges must be set up properly taking into consideration the size,
tonnage, speed, turning performance and other characteristics of own ship.

WARNING

The CPA/TCPA alarm feature should never be relied
upon as a sole means for detecting the risk of collision.
The navigator is not relieved of the responsibility to keep
visual lookout for avoiding collisions, whether or not the
radar or other plotting aid is in use.

Follow the steps shown below to set the CPA/TCPA alarm ranges:

1. Open the "ARP MENU".

2. On the "CPA Set"line, select a CPA limit desired.(Off,0.5,1,2,3,5,6nm)

3. Press the [ACQ/ENTER] key.

4. On the "TCPA Set"line, select a TCPA limit desired.(30s,1,2,3,4,5,6,12M)

5. Press the [ACQ/ENTER] key.

6. Press the [MENU] key to close the menu.

69

The flashing of the triangle plot symbol and vector remain on the screen until the
dangerous situation is no longer present or you intentionally terminate tracking of
the target by using the [SELECT/CANCEL] key.

Lost Target Alarm

When the system detects a loss of a tracked target, the target symbol becomes a
flashing diamond.

70

8. AIS

How AIS Works

Automatic Identification System (AIS) is a reporting system used in the
identification of marine vessels and its location. Vessels equipped with this
system allows each other to communicate automatically, dynamically and
regularly update their position, speed, course and information such as vessel
identity.

How does AIS function as a radar?

The AIS radar function does not refer to its own AIS system and its features
such as the VHF T/R and Letter Machine but by serial interface through
(NMEA) which will be received by the AIS and sent to the radar on a real
time displayed on the radar screen.

How to start the AIS radar feature?

1.Press [MENU] key to open the main menu.

Figure 1 Main menu

71

2. Select [ AIS MENU ] & press [ ACQ/ENTER ] key, Select 1.Display ,

""

press [ ] or [ ] key select On & p ress [ MENU] k ey t o r eturn. N ow

""

if AIS word appears on the upper screen of the display, The AIS symbol
is shown in the radar echo area.

NOTE: If the AIS signal is received, the AIS function is still at work even

""

Figure 2 AIS menu

when the signal does not appear and still continues to ensure real time AIS
information.

How to check the information received from Ships with AIS ?

In the AIS menu, select AIS Ship Listing and press [ACQ/ENTER].
The AIS tabulation will appear and demonstrate the other ships basic
information.

""

Figure 3 AIS Ship Listing

72

How to determine the target ships detailed information

There are two methods by which we can view a ships sailing detailed
information:

1. By keyboard
From the list of AIS information, select the direction key and press
[ACQ/ENTER] , on Figure 3 , the detailed data of the current selected ship
information shall be displayed.

2. By cursor
When the cursor is moved to the target ship the

and press [ENTER] key,

selected ship will appear as shown in Figure 4 and the AIS data shall appear
as shown in Figure 5.

Note: If the display setting of the radar screen is at ALL mode, it will
briefly display the AIS information as shown in Figure 6.

""

Figure 4 Selected target display

Figure 5 AIS Detailed data frame

AIS VESSEL

VESSEL 1

SPD 12.0KT
RNG 20.0NM
CPA 9.1NM

CRS 128 M
BRG 99
TCPA 24:30:30

Safe

M

Figure 6 AIS brief information

73

How to view your ships AIS information?

Press AIS menu, select Own Ship Data then AIS detailed information will

""

appear as shown in Figure 7.

Figure 7 Own Ship data

Setting vector length of time

This function is used to set your ship and target ships vector length. The
mark represents the vector in accordance with the present voyage. This
value is just an estimate and it will follow the ships movement. However
it can help simplify the radar operators intuitive navigation judgement.

SOG (Speed over ground)

COG (Course over ground)

Turning direction(ROT)

Heading line

(If there is no heading data, the

line points in direction of COG.)

Figure 8 Activated target

Setting method:

Enter AIS menu, select "Vector length" and press [ACQ/ENTER] key, then
use the direction key choose corresponding time, and press the
[ACQ/ENTER] key.

74

Past Position Display

The past position display shows equally time-spaced dots marking past
positions of activated AIS targets. A new dot is added at preset time intervals
until the preset number is reached. If a target changes its speed, the spacing
will be uneven. If it changes course, its plotted course will not be a straight
line.
Below are sample past position displays.

(a) Ship turning

(B) Ship turning

Straight

(c) Ship reduced

speed

(d) Ship increased

speed

Figure 9 Sample past position displays

Past position plot interval

Enter AIS menu, select "History" t o s elect p lot in terval d esired: O ff,
15s, 30s, 1, 2, 3 or 6 min. Select OFF to erase all past position points and
turn off the past position display.

AIS Collision Alarm (CPA, TCPA)

The AIS continuously monitors the predicted range at the Closest Point of
Approach (CPA) and predicted time to CPA (TCPA) of each AIS target.
When the predicted CPA of an AIS target becomes smaller than a preset
CPA range and its predicted TCPA less than a preset TCPA limit, the audio
alarm sounds and the symbol of the offending AIS target becomes red,
bold 2 times and flashes together with its vector.

CPA/TCPA alarm ranges must be set up properly taking into consideration
the size, tonnage, speed, turning performance and other characteristics of

own ship.

75

Setting the CPA and TCPA ranges

Enter AIS menu, select CPA. Set & TCPA. Set , then press direction

key choose the value you want.

Below are CPA & TCPA can be setup value
CPA. Set Off, 0.5, 1, 2, 3, 5, 6 nm
TCPA. Set 30 s, 1, 2, 3, 4, 5, 6, 12 min

In/Out harbour

This function is used to avoid ships in the harbour because too many AIS
boats nearby may cause continuous alarm. Upon entering the port you may
select "ON" , CPA and TCPA alarm will be disabled.

Setting IN/OUT harbour

Enter AIS menu, select In/Out Harbour , use direction key

to

set.

Loss target alarm function

If the current range of AIS targets within the information given by the
maximum update interval had not yet received, will be loss target alarm
function is triggered, in this case, the target becomes the symbol shown
below loss target mark, symbol color is red and flash, while the radar alarm
will sound to remind the operator out to pay attention. To manually stop the
audible alarm, press the [SELECT/CANCEL] key once.

Figure10 loss target display symbol

How to open the loss target alarm function

Did not turn this function on the LOSS target symbol will still be displayed,
but does not trigger the alarm. Start as follows:

1. Into the AIS menu and select "Lost target alarm";

2. Press the arrow keys to select "On" and press the [ACQ/ENTER];

3. Press [MENU] key 2 times to exit.

76

Prompted of data processing

The radar system can access a variety of NMEA data, including AIS / GPS,
direction and water depth data. At boot time, if not turned on AIS, the radar
will appear on-screen prompts such as: "No AIS device." To know there are
many, such as "AIS signal loss" etc. To turn off the prompt, press the

[ACQ/ENTER] key.

AIS ship symbol status description

SYMBOL

STAT US REMARKS

Sleeping target

Activated target

ROT higher than preset

ROT

Target selected for data

display

Dangerous target

An isosceles, acute-angled triangle should be used
with its centroid representing the target's reference
position. The most acute apex of the triangle should
be aligned with the heading of the target, or with its
COG, if heading information is not available. The
symbol of the sleeping target may be smaller than
that of the activated target.

All AIS symbols shown with thick line.

Displayed for turning ship.

Broken square is overlaid on target selected to
display its data.

Displayed when CPA/TCPA is within CPA/TCPA LIMIT.
Red in color. Flashing .u ntil acknowledged.

Lost target

“X” overlaid on a lost target. Erased after
acknowledged.

Figure13 AIS ship symbol description

77

Other symbol description

Other AIS symbols that may appear are shown in the table below.

SYMBOL Meaning

Real AIS AtoN

Virtual AIS AtoN

Base Station

Airborne SAR aircraft

AIS SARTS

Figure 14 Other symbol

NO. TYPE COLOR

1

2

Yacht/Fishing/Class B

3

4

5

6

7

8

Military

Tanker/Cargo

Cruise ship

Tug/Pilot

Unknows

ATO N

SART

Gray

Pink

Orange

Violet

White

Blue

Red

Red

With the selected

9

10

11

Loss Target

Danger Target

target color.

Red

Red

REMARK

When blue background
is Black.

Figure15 AIS Icon Color Description

78

9. DISPLAY UNIT AND ANTENNA UNIT SIZE

KR-1238

KR-1268

79

TYPE KRD-1005

NAME DISPLAY UNIT

TYPE KRD-1006

KR-1538

KR-1568

80

NAME DISPLAY UNIT

CABLE ENTRY

4-M10

160

Front

604

64

0

Effective
thread length

25mm

Flat
washer

Spring
washer

Apply silicone sealant

400

Hex bolt

Antenna base plate

Packing

Radome

5 -10 mm

Platform

ONWAONWA

420

270

KR-1238
KR-1538

81

MODE KRA-1003

NAME SCANNER UNIT

1250

RA12

1800

R18A

RADIATOR S=1/25

124

124

13

FIXING HOLES

168

140

240

45

30

150

178

185

MOUNTING DIMEENSIONS

)

(XN8)

540

(XN12A

650

ATION

DIA.OF ROT

CENTER OF ROTSTION

CABLE ENTRY

50

F.W .

FLAT
WASHER

M12 BOLT

SEAL WASHER

PLATFORM

S.W
M12 NUT

CW10530X

KR-1268
KR-1568

MODE KRA-2004

NAME SCANNER UNIT

4-M4 10

82

ABBREVIATIONS

Word

Acknowledge

Adjust, Acquisition

Adjust, Adjustment

Alarm

Anchor Watch

Antenna

Anti Clutter Rain

Anti Clutter sea

Automatic

Automatic Identification System

Bearing

Bow Crossing Range

Bow Crossing Time

Brilliance

Clear

Abbreviations

ACK

ACQ

ADJ

ALARM

ANCH

ANT

RAIN

SEA

AUTO

AIS

BRG

BCR

BCT

BRILL

CLR

Word

Maximum

Medium Pulse

Menu

Minimum

Minute(s)

Nautical Mile(s)

Navigation

Normal

Normal

North

North

North Up

Off

Offset

On

Abbreviations

MAX

MP

MENU

MIN

Min

NM

NAV

NORM

NORMAL

N

NORTH

N UP

OFF

OFFSET

ON

Closest Point of Approach

Consistent Common Reference Point

Contrast

Course

Course Up

Course Over the Ground

Course Through the Water

Cursor

Delete

Depth

Depth

Differential GPS

Drift

East

Echo Reference

Electronic Bearing Line

CPA

CCRP

CONT

CRS

CUP

COG

CTW

CURS

DEL

DEPTH

DPTH

DGPS

DRIFT

E

REF

EBL

Out/Output

Own Ship

Panel Illumination

Parallel Index Line

Past Positions

Performance Monitor

Port/Portside

Position

Power

Rain

Range Rings

Rate Of Turn

Reference

Relative

Map(s)

Maritime Mobile Services Identity number

OUT

OS

PANEL

PI

PAST POSN

PM

PORT

POSN

PWR

RAIN

RR

ROT

REF

REL

MAP

MMSI

Enter

Enter

ENT

ENTER

Relative Motion

Revolutions Per Minute

83

RM

RPM

Word

Abbreviations Word Abbreviations

Error

Error

Estimated Time of Arrival

Fathom(s)

Feet/Foot

Full

Full

Gain

Global Positioning System

Ground

Guard Zone

Gyro

Head Up

Head Up

Heading

Heading Line

ERR Route ROUTE

ERROR S-Band S-BAND

ETA

Fm

ft

FUL Short Pulse

FULL Speed

GAIN Speed Over the Ground SOG

GPS

GND Stabilized STAB

GUARD Standby

GYRO

H UP Symbol(s) SYM

HEAD UP Symbol(s)

HDG

HL

Search And Rescue Transponder

Second(s) SEC

Select SEL

Speed Through the Water STW

Starboard/Starboard Side STBD

Target

Target Tracking

SART

SP

SPD

STBY

SYMBOL

TGT

TT

Indication

Interference Rejection

Interval

Interval

Kilometre

Knot(s)

Latitude

Latitude/Longitude

Log

Long Pulse

Longitude

Lost Target

Magenta

Man Overboard

Manual

Manual

Marker

Marker

Master

IND

IR Time TIME

INT

INTERVAL

Km

Kn

LAT

L/L

LOG

LP

LON

LOST TGT

MAG

MOB

MAN

MANUAL

MKR

MARK

MASTER

Tes t

Time to CPA

Time To Go

Track

Tracking

Trail(s)

Transmit

Trigger Pulse

Tune

True

True Motion

Variable Range Marker

Vector

Voyage Data Recorder

Warning

Waypoint

X-Band

TEST

TCPA

TTG

TRK

TRKG

TRAIL

TX

TRIGGER

TUNE

T

TM

VRM

VECT

VDR

WARNING

WPT

X-BAND

84