Furuno 1623 User manual

MARINE RADAR
MODEL 1623

Your Local Agent/DealerYour Local Agent/Dealer
9-52 Ashihara-cho,9-52 Ashihara-cho,
Nishinomi
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anNishinomi
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an
Tele
p
hone :Tele
p
hone : 0798-65-21110798-65-2111
Telefax :Telefax : 0798-65-42000798-65-4200
FIRST EDITION :FIRST EDITION : .. 00000000
Printed in JapanPrinted in Japan
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hts reserved.
PUB.No.PUB.No. OME-35100OME-35100
(( )) MODEL1623MODEL1623
*OME35100Z00**OME35100Z00*
*OME35100Z00**OME35100Z00*
* O M E 3 5 1 0 0 Z 0 0 ** O M E 3 5 1 0 0 Z 0 0 *

i
SAFETY INSTRUCTIONS
WARNING
ELECTRICAL SHOCK HAZARD
Do not open the equipment.
Only qualified personnel
should work inside the
equipment.
Turn off the radar power
switch before servicing the
antenna unit. Post a warning
sign near the switch indi-
cating that it should not be
turned on while the antenna
unit is being serviced.
Prevent the potential risk of
being struck by the rotating
antenna and exposure to
RF radiation hazard.
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.
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 equip-
ment is emitting smoke or fire.
Continued use of the equipment can cause
fire or electrical shock.
WARNING
Use the proper fuse.
Use of a wrong fuse can damage the
equipment and void the warranty.
Keep heater away from equipment.
Heat can alter equipment shape and melt
the power cord, which can cause fire or
electrical shock.
NOTICE
A warning label is attached to the
equipment. Do not remove the label.
If the label is missing or damaged,
contact a FURUNO agent or dealer.
WARNING
To avoid electrical shock, do not
remove cover. No user-serviceable
parts inside.
Name: Warning Label (1)
Type: 86-003-1011-0
Code No.: 100-236-230
Safety Instructions for the Operator

ii
Safety Instructions for the Installer
Ground the equipment to
prevent mutual interference.
NOTICE
Observe the following compass safe
distances to prevent interference to a
magnetic compass:
Standard Steering
compass compass
TBA TBA
Antenna
unit TBA TBA
Display
unit
Do not open the equipment
unless totally familiar with
electrical circuits and
service manual.
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.
WARNING
Construct a suitable service platform
from which to install the antenna unit.
Serious injury or death can result if some-
one falls from the radar antenna mast.
Be sure that the power supply is
compatible with the voltage rating of
the equipment.
Connection of an incorrect power supply
can cause fire or damage the equipment.
Use only the specified power cable.
Fire or equipment damage can result if a
different cable is used.
ELECTRICAL
SHOCK
HAZARD

iii
TABLE OF CONTENTS
FOREWORD............................................iv
SYSTEM CONFIGURATION.....................v
EQUIPMENT LISTS.................................vi
1. OPERATION........................................1
1.1 Controls ............................................... 1
1.2 Indications ...........................................2
1.3 Turning Power On/Off..........................3
1.4 Transmitting, Standby..........................3
1.5 Adjusting Display Contrast, Brilliance.. 3
1.6 Choosing the Range............................4
1.7 Receiver Sensitivity .............................4
1.8 Suppressing Sea Clutter......................5
1.9 Suppressing Rain Clutter.....................6
1.10 Measuring the Range .......................... 6
1.11 Measuring the Bearing ........................7
1.12 Shifting the Display..............................7
1.13 Zoom.................................................... 8
1.14 User Menu Overview ........................... 8
1.15 Heading Line .......................................9
1.16 Interference Rejector ...........................9
1.17 Noise Rejector ..................................... 9
1.18 Echo Trail, Trail Brilliance ....................9
1.19 Echo Stretch ......................................10
1.20 Guard Alarm ...................................... 10
1.21 Watchman.......................................... 11
1.22 Suppressing Long-range Rain
Clutter ................................................. 11
1.23 Panel Backlighting ............................. 12
1.24 Hue ....................................................12
1.25 Resetting Distance Run.....................12
1.26 PROG Key......................................... 12
1.27 Turning Navigation Data On/Off ........13
1.28 Outputting Cursor Position to
Navigator .......................................... 13
1.29 Setting up Nav Data Displays............13
1.30 System Menu..................................... 15
1.31 Installation Menu ...............................16
2. MAINTENANCE,
TROUBLESHOOTING ...................... 18
2.1 Maintenance ..................................... 18
2.2 Replacing the Fuse ........................... 19
2.3 Troubleshooting ................................ 19
2.4 Diagnostics ....................................... 20
2.5 Test Pattern ....................................... 21
2.6 Replacing the Magnetron ................ 21
2.7 Replacing the Synchro Belt............... 21
3. INSTALLATION................................. 22
3.1 Antenna Unit Installation ................... 22
3.2 Display Unit Installation..................... 24
3.3 Wiring ................................................ 25
3.4 Adjustments ...................................... 26
3.5 Magnetron Heater Voltage ................ 28
SPECIFICATIONS
OUTLINE DRAWINGS
INTERCONNECTION DIAGRAM
SCHEMATIC DIAGRAMS

iv
FOREWORD
A Word to the Owner of the
MODEL 1623
Congratulations on your choice of the
MODEL 1623 Marine Radar.
For over 50 years FURUNO Electric
Company has enjoyed an enviable reputation
for innovative and dependable marine
electronics equipment. This dedication to
excellence is furthered by our extensive
global network of agents and dealers.
Your radar is designed and constructed to
meet the rigorous demands of the marine
environment. However, no machine can
perform its intended function unless installed,
operated and maintained properly. Please
carefully read and follow the recommended
procedures for installation, operation, and
maintenance.
We would appreciate hearing from you, the
end-user, about whether we are achieving our
purposes.
Thank you for considering and purchasing
FURUNO equipment.
Features
Your radar has a large variety of functions, all
contained in a rugged plastic case. All
controls respond immediately to the
operator’s command and each time a key is
pressed the corresponding change can be
seen on the screen.
The main features of the MODEL 1623 are
• Daylight viewing radar specially designed
for small craft and sailing yachts.
• Traditional FURUNO reliability and quality
in a compact, light-weight and low-cost
radar.
• Compact and light-weight radome
antenna with precision 34 cm center-fed
radiator.
• High definition 6-inch monochrome LCD
display.
• Automatic control of sensitivity (gain),
tuning and A/C SEA for simplified
operation.
• Targets can be displayed in grey tones on
a white background or vice versa, for
optimal viewing under any lighting
conditions.
• On-screen alphanumeric readout of all
operational information.
• User programmable data displays.
• [PROG] key provides menu shortcut.
• Standard features include Display Shift,
EBL, Echo Stretch, Echo Trail, Guard
Alarm, Interference Rejector, VRM, Zoom.
• Guard zone watches for targets entering
(or exiting) a guard zone.
• Operates on 12 V or 24 V DC power.

v
SYSTEM CONFIGURATION
DISPLAY
UNIT
RDP-141
GPS RECEIVER
GP-310B/320B
EXTERNAL
BUZZER
OP03-136
SHIP'S MAINS
12/24 VDC
WIND INDICATOR,
SPEED INDICATOR
RECTIFIER
PR-62
SHIP'S MAINS
100/110/115/220/230 VAC
NAVIGATOR
or ECHO SOUNDER
(NMEA 0183)
: Standard supply
: Optional supply
ESC
MENU
MODE
GAIN
ALARM
RANGE
MARKPROG
POWER
BRILL
MODEL 1623
MARINE RADAR
FURUNO
ANTENNA UNIT
RSB-0060

vi
EQUIPMENT LISTS
Standard supply
Name Type Code No. Qty Remarks
Antenna Unit RSB-0060 −1
Display Unit RDP-141 −1
Installation Materials 1 set
Spare Parts SP03-09800 000-085-441 1 set Fuses (2 pcs.)
Installation Materials
Name Type Code No. Qty Remarks
Antenna Cable (10 m) MJ-A10SPF-0003-100
Antenna Cable (15 m) MJ-A10SPF-0009-150
Antenna Cable (20 m) MJ-A10SPF-0009-200
1
Power Cable Assy. MJ-A3SPF-0013-035 1 Connector, fuse, 3.5 m
Hex Head Bolt M10X25 000-862-308 4 For antenna unit
Dummy Film 03-118-1103-0 100-185-380 1 set For display unit
Tapping Screw 5X20 000-802-081 4 For display unit
EMI Core RFC-10 000-141-085 1 For antenna cable
Washer Head Screw M4X15 000-881-448 1 For antenna cable
Fixing Band 03-146-0101-0 100-277-850 1 For antenna cable

vii
Optional Equipment
Name Type Code No. Qty Remarks
NMEA Cable Assy. MJ-A6SPF0003-050 000-117-603 1 Connector at a end, 5 m
NMEA Distribution
Cable Assy. MJ-A15A7F0004-005 000-145-690 1
Antenna Cable Assy. 03S9175 000-130-034 1 Connector at one end,
24 V spec. only.
Radome Mounting
Bracket OP03-93 008-445-080 1 For sailboat
External Buzzer OP03-136 000-086-443 1 Connector at one end, 1 m
PR-62 000-013-484 100 VAC
PR-62 000-013-485 110 VAC
PR-62 000-013-486 220 VAC
Rectifier
PR-62 000-013-487
1
230 VAC

1
1. OPERATION
1.1 Controls
Cursor Pad
Chooses menu items;
adjusts VRM, EBL and cursor.
Opens/closes menu;
escapes from current
operation.
Chooses display mode.
Adjusts gain.
Chooses radar range.
Enables/disables guard alarm.
Displays user-programmed
pop-up window.
Long press: Turns power on/off.
Momentary press: Adjusts display contrast
and brilliance.
Displays Mark menu to
adjust EBL and VRM;
output cursor latitude and
longitude position to a
navigator.
ESC
MENU
MODE
GAIN
ALARM
RANGE
MARKPROG
POWER
BRILL
MODEL 1623
MARINE RADAR
FURUNO
Display unit
How to remove the hard cover
Place your thumbs at the center of the cover, and then lift the cover while
pressing it with your thumbs.

2
1.2 Indications
3M TRAIL
G(IN)
FTC
ES H
IR H
EBL
VRM 45.0°
1.25 nm
RNG 06.2nm
BRG 283.2°
TTG: 02H21M
1.5
nm
0.5
ZOOM
Range
Range ring
interval
Zoom
(flashing)
Echo trails setting
Guard alarm (IN or OUT)
Rain clutter suppressor
Echo stretch
Interference rejector
Guard
zone
Cursor
EBL
Range rings
Range, bearing and
time-to-go to cursor
location
(Cursor latitude and
longitude position
also available if radar
is interfaced with
a navigator.)
EBL bearing
VRM range
VRM
Watchman
Heading line
WATCHMAN
SIM
Simulation mode
Indications

3
1.3 Turning Power On/Off
Press the [POWER/BRILL] key more than
one second to turn on the power. The unit
beeps, the startup screen appears, and then
the equipment checks the ROM and RAM for
proper operation and displays program
number.
Note: The ROM and RAM check shows OK
or NG (No Good). If NG appears, try to press
any key except the [POWER/BRILL] key to
start operation. However, the equipment may
not work properly. Contact your dealer for
advice.
XX = Program version no.
ROM : OK RAM : OK
Program No: 0359183-0XX
MODEL 1623
FURUNO ELECTRIC CO., LTD.
Startup screen
After the completion of the startup test, a
timer displays the time remaining for warm up
of the magnetron (the device which transmits
radar pulses), counting down from 1:00 to
0:00.
To turn off the power, press and hold down
the [POWER/BRILL] key until the screen
goes blank. The time remaining until power is
turned off is counted down on the screen.
Provided that the radar was once in use with
the magnetron still warm, you can put the
radar into TRANSMIT status without the
one-minute stand-by.
If the power switch was turned off by mistake
and you want to restart the radar promptly do
the following:
1. Press the [POWER/BRILL] key not later
than five seconds after power-off.
2. Press the [MODE] key to put the radar
into TRANSMIT status.
Quick Start
Note: The example screens shown in this
manual may not match the screens you see
on your display. The screen you see depends
on your system configuration and equipment
settings.
1.4 Transmitting, Standby
After the power is turned on and the
magnetron has warmed up, “ST-BY”
(Stand-By) appears at the screen center,
indicating the radar is ready to transmit radar
pulses.
Use the [MODE] key to toggle between
transmit and standby. Echoes appear in four
levels of digitized video according to echo
strength. When a target is beneath a marker
(VRM, EBL, heading line, range ring) the part
of the marker where the target lies is
displayed in reverse video.
Note: If you press the [MODE] key before
ST-BY appears, the buzzer sounds and the
radar does not transmit pulses. Wait until
ST-BY appears.
1.5 Adjusting Display
Contrast, Brilliance
1. Press the [POWER/BRILL] key
momentarily to show the
brilliance/contrast adjustment window.
CONT: 4
LOW HIGH
BRILL:
LOW HIGH
9
BRILL/CONTRAST
[MODE]: TX/ST-BY
Brilliance/contrast adjustment window
2. Press ◄or ►to adjust contrast.
3. Press ▲or ▼to adjust brilliance.
4. Press the [MODE] key to escape.

4
Note 1: Windows other than those on menus
are erased when there is no operation within
about seven seconds.
Note 2: When the power is reapplied after
turning off the equipment with minimum
brilliance, the radar starts up with minimum
brilliance, after the initial start up. Adjust the
brilliance as necessary.
1.6 Choosing the Range
The range selected automatically determines
the range ring interval, the number of range
rings and pulse repetition rate.
Press the [RANGE+] or [RANGE-] key to
select a range. The range and range ring
interval appear at the top left corner on the
screen.
Range
Range ring
interval
6.0 nm
2.0
RNG 03.2nm
BRG 60.2°
TTG: 02H21M
Location of range and range ring
interval indications
1.7 Receiver Sensitivity
The [GAIN] key 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.
You can adjust the sensitivity manually, or let
the unit do it automatically. In either case, the
proper setting is such that the background
noise is just visible on the screen. For manual
adjustment, use the highest range since the
background noise is clearer.
If you set up for too little sensitivity, weak
echoes may be missed. On the other hand
excessive sensitivity yields too much
background noise; weak targets may be
missed because of the poor contrast between
desired echoes and the background noise on
the display.
1. Press the [GAIN] key once or twice to
show the display below.
GAIN
20
[GAIN] : A/C SEA MENU
[MENU/ESC] : EXIT
AUTO : MODERATE
MANU
Gain adjustment window
2. Use ▲or ▼to choose AUTO or MANU
as appropriate.
3. Do one of the following depending on the
choice you made at step 2.
Automatic adjustment
a) Press ►to open the automatic gain
options window.
ROUGH
MODERATE
CALM
Automatic gain options
b) Choose ROUGH, MODERATE or
CALM depending on sea conditions.
c) Press ◄to close the window.
Manual adjustment
While observing the screen and the tuning
bar, use ◄or ►to set the gain. The
setting range is 0-100.
4. Press the [MENU/ESC] key to finish.

5
1.8 Suppressing Sea Clutter
In rough weather, returns from the sea
surface, called sea clutter, are received over
several miles around own ship and mask
nearby targets. This situation can be
improved by properly suppressing the sea
clutter with the A/C SEA control.
In most cases suppress the clutter until it has
disappeared to leeward, but a little is still
visible windward. If the setting is 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.
A common mistake is too over-suppress sea
clutter so that the surface clutter is completely
removed. You can see how dangerous this
can be by setting up for maximum A/C SEA: A
dark zone will be created near the center of
the screen, causing a loss of close-in targets.
This dark zone is even more dangerous if the
sensitivity has not been properly adjusted.
Always leave a little sea clutter visible on the
screen. If no clutter is observed (on very calm
waters), turn off the A/C SEA circuit.
Sea clutter at screen center
1. Press the [GAIN] key once or twice to
show the display below.
A/C SEA
20
[GAIN] : A/C RAIN MENU
[MENU/ESC] : EXIT
AUTO : MODERATE
MANU
A/C SEA adjustment window
2. Use ▲or ▼to choose AUTO or MANU
as appropriate.
The auto A/C SEA can erase weak targets.
CAUTION
3. Do one of the following depending on the
choice you made at step 2.
Automatic adjustment
a) Press ►to open the automatic A/C
SEA options window.
ROUGH
MODERATE
CALM
A/C SEA options
b) Choose ROUGH, MODERATE or
CALM depending on sea conditions.
c) Press ◄to close the window.
Manual adjustment
While observing the screen and the tuning
bar, use ◄or ►to set the A/C SEA. The
setting range is 0-100.
4. Press the [MENU/ESC] key to finish.

6
1.9 Suppressing 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
antenna will also pick up rain clutter (rain,
snow, or hail) in the same manner as normal
targets. The illustration below shows the
appearance of rain clutter on the display.
The A/C RAIN control adjusts the receiver
sensitivity as the A/C SEA control does but
rather in a longer time period (longer range).
The higher the setting the greater the
anti-clutter effect.
Rain clutter at screen center
1. Press the [GAIN] key once or twice to
show the display below.
A/C RAIN
[GAIN] : GAIN MENU
[MENU/ESC] : EXIT
65
A/C RAIN adjustment window
2. While observing the screen and the tuning
bar, use ◄or ►to adjust the A/C RAIN.
The setting range is 0-100.
3. Press the [MENU/ESC] key to finish.
1.10 Measuring the Range
The bearing to a target can be measured by
the range rings, by the cursor and by the
VRM (Variable Range Marker).
Measuring range by the range rings
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 inner edge of the nearest
ring.
Note: The range rings can be turned on or off
with RINGS on page 1 of the System menu.
Measuring range by VRM
1. Press the [MARK] key to show the Mark
menu.
MARK MENU
[GAIN] : EBL
[ALARM] : VRM
MARK] : OUTPUT TLL
Mark menu
2. Press the [ALARM] key to display the
VRM, which is a dashed line to
distinguish it from the heading line.
“VRM,” displayed in reverse video,
appears at the bottom left corner.
3. Operate the cursor pad to place the VRM
on the inside edge of the target.
4. Check the VRM readout at the bottom left
corner on the screen to find the range to
the target.
To fix the VRM on the screen, press the
[MENU/ESC] key. To erase the VRM, press
the [ALARM] key.
6.0
nm
2.0
VRM 2.91 nm
Target
VRM
VRM
range
Range, bearing
and time-to-go
to cursor
location
RNG 2.91nm
BRG 45.62°
TTG: 02H21M
Cursor
How to measure the range with the
VRM and cursor

7
1.11 Measuring the Bearing
The bearing to a target can be measured with
the cursor and the EBL (Electronic Bearing
Line).
Measuring bearing with the cursor
Use the cursor pad to place the cursor on the
inside edge of the target.
Measuring bearing with the EBL
1. Press the [MARK] key to show the Mark
menu.
MARK MENU
[GAIN] : EBL
[ALARM] : VRM
MARK] : OUTPUT TLL
Mark menu
2. Press the [GAIN] key to show the EBL.
3. Operate the cursor pad to bisect the
target with the EBL.
4. Check the EBL readout at the bottom left
corner on the screen to find the bearing to
the target.
To fix the EBL on the screen, press the
[MENU/ESC] key. To erase the EBL, press
the [GAIN] key.
6.0 nm
2.0
EBL 45.62 °
EBL
bearing
RNG 2.22nm
BRG 45.62°
TTG: 02H21M
Range, bearing
and time-to-go
to cursor
location
Target
EBL Cursor
Measuring range by the EBL and cursor
1.12 Shifting the Display
Own ship position, or sweep origin, can be
displaced manually or automatically to
expand the view filed without switch to a
longer range. The default shift method is
manual. For automatic shift, see SHIFT
MODE on page 16.
1. Use the cursor pad to place the cursor
where you want to shift own ship position.
2. Press the [MODE] key to show the
Display Mode menu.
SELECT DISPLAY MODE
[MENU/ESC] : Exit
SHIFT (MANUAL)*
NORMAL
ZOOM
NAV DISP OFF ON
* AUTO may appear instead of MANUAL
depending on menu setting.
Display mode menu
3. Use ▲to choose SHIFT (MANUAL).
Note: If SHIFT (AUTO) is shown, open
the System menu and set SHIFT MODE
to MANUAL. For further details, see
paragraph 1.30.
4. Press the [MENU/ESC] key to close the
menu.
Select where to shift Shifted display
with the cursor.
How shift works
To cancel the shifted display, open the
Display Mode menu, choose NORMAL and
then press the [MENU/ESC] key.

8
1.13 Zoom
The zoom feature allows you to double the
size of the area between your boat and any
location within the current range to take a
closer look at an area of interest.
1. Use the cursor pad to place the cursor
where you want to zoom.
2. Press the [MODE] key to show the display
mode menu.
SELECT DISPLAY MODE
[MENU/ESC] : Exit
SHIFT (MANUAL)*
NORMAL
ZOOM
NAV DISP OFF ON
* AUTO may appear instead of MANUAL
depending on menu setting.
Display mode menu
3. Use ▲or ▼to choose ZOOM.
4. Press the [MENU/ESC] key to close the
menu.
To cancel the shifted display, open the
Display Mode menu, choose NORMAL and
then press the [MENU/ESC] key.
1.14 User Menu Overview
The User menu contains 11 items which the
user may set according to conditions.
1. Press the [MENU] key to open the User
menu.
P
(1/3)
INT REJECTION LOW
ECHO STRETCH : LOW
FTC : OFF
NOISE REJECTION: LOW
[MENU/ESC] : Exit
*
* = "P" shows current function of PROG key
User menu, page 1
2. Use ▲or ▼to scroll the menu to display
desired item in reverse video.
Page 2
(3/3)
Page 3
WATCHMAN OFF
HUE : DAY
PANEL DIMMER : OFF
HDG LINE OFF
[MENU/ESC] : Exit
(2/3)
ECHO TRAIL OFF
TRAIL BRILL : LOW
RESET TRIPLOG : OFF
GO TO SYSTEM MENU
[MENU/ESC] : Exit
User menu, page 2 and page 3
3. Press ►to show the options window for
the item selected. For example, the
illustration below shows the options
window for the interference rejector.
OFF
LOW
MED
HIGH
Interference rejector options
4. Use ▲or ▼to select option desired.
5. Press ◄to continue menu operation, or
press the [MENU/ESC] key to register
your selection and close the User menu.
User menu description
Item Description
INT
REJECTION
Rejects radar interference.
ECHO
STRETCH
Stretches echoes in range
direction or range and bearing
direction.
FTC Reduces rain clutter.
NOISE
REJECTION
Rejects noise.
WATCHMAN Periodically checks for targets
in guard zone.
HUE Chooses picture color.
PANEL
DIMMER
Adjusts panel backlighting.
HDG LINE
OFF
Temporarily turns the heading
line off.
ECHO TRAIL Shows echo movement.
TRAIL BRILL Adjusts trail brilliance.
RESET TRIP
LOG
Resets distance run.

9
1.15 Heading Line
The heading line indicates the ship’s heading
and it is the solid line which appears at zero
degrees on the bearing scale.
To temporarily erase the heading line to look
at targets existing dead ahead of own ship,
do the following:
1. Press the [MENU/ESC] key to open the
User menu.
2. Choose HDG LINE OFF from page 2.
3. Press ►to turn the heading line off. The
line stays off while ►is pressed.
4. Press the [MENU/ESC] key to close the
menu.
1.16 Interference Rejector
Mutual radar interference may occur in the
vicinity of another shipborne radar operating
in the same frequency band (9 GHz). It is
seen on the screen as a number of bright
spikes either in irregular patterns or in the
form of usually curved spoke-like dotted lines
extending from the center to the edge of the
picture. This type of interference can be
reduced by activating the interference rejector
circuit. "IR” and the rejection level indicator “L,
M or H” appear at the top right corner when
the interference rejector circuit is on.
Appearance of interference
Turn off the interference rejector when no
interference exists, to avoid missing small
targets.
1. Press the [MENU/ESC] key to open the
User menu.
2. Choose INT REJECTION from page 1.
3. Press ►to open the options window.
4. Choose OFF, LOW, MED or HIGH as
appropriate.
5. Press the [MENU/ESC] key to finish.
1.17 Noise Rejector
The noise rejector suppresses white noise,
which appears on the screen as many dots
scattered randomly over the display.
1. Press the [MENU/ESC] key to open the
User menu.
2. Choose NOISE REJECTION from page 1.
3. Press ►to open the options window.
4. Choose OFF, LOW, MED or HIGH as
appropriate.
5. Press the [MENU/ESC] key to close the
menu.
1.18 Echo Trail, Trail Brilliance
Echo trails are simulated afterglow of target
echoes that represent their movements
relative to own ship.
3M TRAIL
Trail time (3 min)
Echo trail
Echo trails
1. Press the [MENU/ESC] key to open the
User menu.
2. Choose ECHO TRAIL from page 3.
3. Press ►to open the options window.
OFF
30sec
1min
3min
6min
CONT
Echo trail options
4. Choose appropriate time.

10
5. Press ◄to close the options window.
6. Press ▼to choose TRAIL BRILL.
7. Press ►to open the options window.
8. Choose LOW or HIGH as appropriate.
9. Press the [MENU/ESC] key to close the
menu.
1.19 Echo Stretch
On long ranges target echoes tend to shrink
in the range direction, making them difficult to
see. On short and medium ranges such as
1.5, 3 and 6 nm range scales, the same sized
targets get smaller on screen as they
approach own ship. This is due to the
inherent property of the radiation pattern
produced by the antenna. To enhance target
video, use the echo stretch feature.
1. Press the [MENU/ESC] key to open the
User menu.
2. Choose ECHO STRETCH from page 1.
3. Press ►to open the options window.
4. Choose OFF, LOW or HIGH as
appropriate. LOW stretches echoes in the
bearing direction; HIGH stretches echoes
in the range and bearing directions. The
display shows “ES L” or “ES H” depending
on your selection.
5. Press the [MENU/ESC] key to close the
menu.
Echo
ES L ES H
Brg dir. Brg dir.
Rng
dir.
Echo Stretch Echo Stretch Echo Stretch
OFF LOW HIGH
How echo stretch works
1.20 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, the audio alarm
sounds to call your attention. The alarm will
sound on targets entering or exiting the zone
depending on zone status after setting the
alarm.
*The alarm should not be relied upon as the
sole means for detecting possible collision
situations.
*A/C SEA, A/C RAIN, FTC and GAIN controls
should be properly adjusted to be sure the
alarm system does not overlook target echoes.
NOTICE
Setting a guard zone
1. Operate the cursor pad to place the
cursor at the top left corner for the zone
and then press the [ALARM] key.
2. Operate the cursor pad to place the
cursor at the bottom right corner for the
zone and then press the [ALARM] key.
Guard
zone
to set
* GUARD
1) Drag cursor to
top left corner for
zone and press
[ALARM].
Asterisk blinking
Drag cursor
here.
Mentally create
the guard zone to set.
2) Drag cursor to
bottom right corner
for zone and press
[ALARM].
Guard zone completed.
Guard
zone
Drag cursor
here.
* GUARD
GUARD
How to set a guard zone

11
How guard zone type is determined
After the guard zone is set, the system
checks for the existence of targets inside the
guard zone, which takes about 8 to 12
seconds. When the check is completed,
“G(IN)” or “G(OUT)” replaces GUARD at the
top right corner.
G(IN): When no target exists in the zone,
"G(IN)" appears. The audio alarm sounds to
targets which enter the guard zone.
G(OUT): If there are targets in the guard
zone, "G(OUT)" appears. The audio alarm
sounds on all targets which exit from the
guard zone.
(a) Inward target alarm (b) Outward target alarm
Inward and outward alarms
Note: When the radar range is less than one
half of the guard zone range, the guard zone
disappears and the indication "UP RNG"
replaces G(IN) or G(OUT). If this happens,
raise the range to redisplay the guard zone.
Silencing the audio alarm
When a target violates the guard zone, the
target flashes and the audio alarm sounds.
You can silence the audio alarm with the
[ALARM] key. When this is done, GUARD
(displayed in reverse video) replaces G(IN) or
G(OUT) and the guard zone is displayed in
reverse video. This means the guard alarm is
temporarily deactivated. Press the key again
to reactivate the guard alarm.
Canceling the guard zone and guard
alarm
Press and hold down the [ALARM] key until
the guard zone is erased.
1.21 Watchman
The watchman function periodically transmits
the radar for about one minute to check for
targets in a guard zone. If change is found in
the zone from the previous transmission, the
audio alarm sounds, watchman is canceled
and the radar transmits. This feature is useful
when you do not need to observe the radar
continuously but want to be alerted to radar
targets in a specific area, namely, the guard
zone. When the radar starts transmitting, the
buzzer sounds to alert you.
1. Press the [MENU/ESC] key to open the
User menu.
2. Choose WATCHMAN from page 2.
3. Press ►to open the options window.
OFF
5min
10min
20min
Watchman time options
4. Choose appropriate time out, that is, the
amount of time the radar is in stand-by,
among 5, 10 and 20 minutes.
5. Press the [MENU/ESC] key to close the
menu.
1.22 Suppressing Long-range
Rain Clutter
In adverse weather, clouds, rain or snow
produce spray-like spurious echoes which
impair target detection over a long distance.
These echoes can be suppressed by turning
on the FTC.
1. Press the [MENU/ESC] key to open the
User menu.
2. Choose FTC from page 1.
3. Press ►to open the options window.
4. Choose OFF or ON as appropriate.
5. Press the [MENU/ESC] key to close the
menu.