Furuno Radar Detector 851 MARK 2 User Manual
MARINE RADAR  
MODEL 851 MARK-2  
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SAFETY INSTRUCTIONS  
WARNING  
WARNING  
Do not open the equipment.  
Do not disassemble or modify 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.  
Fire, electrical shock or serious injury can  
result.  
ELECTRICAL  
SHOCK  
Turn off the power immediately if water  
leaks into the equipment or the  
HAZARD  
equipment is emitting smoke or fire.  
Wear a safety belt and hard  
hat when working on the  
antenna unit.  
Fire or equipment damage can result if a  
different cable is used.  
Serious injury or death can  
result if someone falls from  
the radar antenna mast.  
Keep heater away from equipment.  
Heat can alter equipment shape and melt  
the power cord, which can cause fire or  
electrical shock.  
Stay away from transmitting  
antenna.  
The radar antenna emits mi-  
crowave 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.  
CAUTION  
Use the proper fuse.  
Use of a wrong fuse can result in fire or  
permanent equipment damage.  
Turn off the radar power  
switch before servicing the  
antenna unit. Post a warn-  
ing sign near the switch  
indicating it should not be  
turned on while the antenna  
unit is being serviced.  
A warning label is attatched to the  
display unit. 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.  
Prevent the potential risk of  
someone begin struck by the  
rotating antenna and expo-  
sure to RF radiation hazard.  
Name: Warning Label (2)  
Type: 03-129-1001-0  
Code No.: 100-236-740  
i
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TABLE OF CONTENTS  
FOREWORD..........................................iv  
SYSTEM CONFIGURATION ..................v  
2.18 Suppressing Noise  
Interference ............................. 2-15  
2.19 Selecting Pulselength............. 2-15  
2.20 Off Centering the Display....... 2-15  
2.21 Echo Trails............................. 2-16  
2.22 Navigation Data Display......... 2-17  
2.23 Echo Stretch (magnifying  
1. PRINCIPLE OF OPERATION  
1.1 What is Radar?...........................1-1  
1.2 How Ships Determined Position  
Before Radar..............................1-1  
1.3 How Radar Determines Range...1-1  
1.4 How Radar Determines  
long range echoes).................. 2-18  
2.24 Selecting Unit of  
Bearing.......................................1-1  
1.5 Radar Wave Speed and Antenna  
Rotation Speed ..........................1-2  
1.6 The Radar Display......................1-2  
Measurement for Range .......... 2-19  
2.25 Selecting Bearing Reference.. 2-19  
2.26 Watchman.............................. 2-19  
2.27 Erasing the Heading Marker... 2-20  
2.28 Deselecting Ranges............... 2-20  
2.29 Displaying Navigation Data  
2. OPERATION  
2.1 Control Description.....................2-1  
2.2 Display Indications and  
During Stand-by....................... 2-20  
2.30 Outputting Cursor Position to  
Navigator ................................. 2-21  
2.31 Displaying Cursor Position,  
Markers......................................2-2  
2.3 Turning the Radar On and Off ....2-2  
2.4 Transmitting................................2-3  
2.5 Selecting the Range ...................2-3  
2.6 Adjusting LCD Backlighting and  
Display Tone...............................2-3  
Range and Bearing to Cursor .. 2-21  
2.32 Visual Alarm Indications......... 2-21  
3. INTERPRETING THE DISPLAY  
3.1 The Radar Wave and Radar  
2.7 Adjusting Control Panel  
Illumination.................................2-4  
2.8 Adjusting GAIN, STC, A.C RAIN  
and FTC.....................................2-4  
2.9 Tuning the Receiver ...................2-6  
2.10 Measuring the Range ...............2-6  
2.11 Measuring the Bearing .............2-7  
2.12 Menu Operation........................2-8  
2.13 Selecting the Display Mode ....2-10  
2.14 The Window Display............... 2-11  
2.15 Selecting the Presentation  
Horizon ...................................... 3-1  
3.2 Target Properties and Radar  
Wave Reflection......................... 3-2  
3.3 Range Resolution ...................... 3-2  
3.4 Bearing Resolution..................... 3-2  
3.5 False Echoes ............................. 3-3  
3.6 SART ......................................... 3-5  
3.7 Racon (Radar Beacon) .............. 3-7  
4. MAINTENANCE &  
TROUBLESHOOTING  
Mode........................................2-12  
2.16 Guard Alarm...........................2-12  
2.17 Suppressing Radar  
4.1 Preventative Maintenance.......... 4-1  
4.2 Replacing the Fuse.................... 4-2  
4.3 Troubleshooting ......................... 4-2  
4.4 Test ............................................ 4-3  
4.5 Replacing the magnetron........... 4-3  
Interference..............................2-14  
ii  
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MENU TREE....................................... A-1  
SPECIFICATIONS............................SP-1  
INDEX.......................................... index-1  
Declaration of Conformity  
iii  
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FOREWORD  
Features  
Congratulations on your choice of the  
FURUNO Marine Radar MODEL 851  
MARK-2. We are confident you will see why  
the FURUNO name has become synonymous  
with quality and reliability.  
Your radar has a large variety of functions, all  
contained in a remarkably small cabinet.  
The main features of the MODEL 851  
MARK-2 are:  
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.  
• Traditional FURUNO reliability and quality  
in a compact, lightweight and low-cost  
radar.  
• Smartly styled, light-weight and compact  
antenna fits even on small yachts.  
Your radar is designed and constructed to  
meet the rigorous demands of the marine  
environment. However, no machine can  
perform its intended function unless properly  
installed and maintained. Please carefully  
read and follow the recommended procedures  
for installation, operation and maintenance.  
• Durable brushless antenna motor.  
• High definition 8" LCD raster-scan display.  
• 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.  
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 FURUNO  
representative or other qualified technician.  
The importance of a thorough installation  
cannot be overemphasized.  
• Watchman feature periodically transmits  
the radar to check for radar targets which  
may be entering (or exiting) the alarm  
zone.  
We would appreciate hearing from you, the  
end-user, about whether we are achieving our  
purposes.  
• Ship’s position in latitude and longitude (or  
Loran C Time Differences), range and  
bearing to a waypoint, ship’s speed,  
heading and course can be shown in the  
bottom text area. (Requires a navigation  
aid which can output such data in NMEA  
0183 format.)  
Thank you for considering and purchasing  
FURUNO equipment.  
• Zoom feature provided.  
• Omnipad makes the selection of target and  
menu items easy.  
iv  
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SYSTEM CONFIGURATION  
enna unit  
Navigation Device  
Echo Sounder  
Remote Display  
FMD-811  
Gyro Converter  
AD-100  
Gyro-  
compass  
External Alarm  
Buzzer OP03-169  
Integrated Heading  
Sensor PG-1000  
Rectifier  
RU-3423  
Option  
Ship's Mains  
Ship's Mains  
12-24 VDC  
100/110/115 VAC  
200/220/230 VAC  
1φ, 50/60 Hz  
MODEL 851 MARK-2  
v
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1. PRINCIPLE OF OPERATION  
1.1 What is Radar?  
1.3 How Radar Determines  
Range  
The term "RADAR" is an acronym meaning  
RAdio Detection And Ranging. It is a  
device which measures the time it takes for  
a pulsed signal to be reflected back from  
an object.  
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  
1.2 How Ships Determined  
Position Before Radar  
The use of echoes to determine position  
did not begin with radar. Ships would sound  
a short blast on their whistles, fire a shot, or  
strike a bell as an aid to navigation when  
running in fog near a rugged shoreline. 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.  
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 in  
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 antenna is pointing when it emits an  
electronic pulse and then receives a  
returning echo. Each time the antenna  
rotates pulses are transmitted in the full  
360 degree circle, each pulse at a slightly  
different bearing from the previous one.  
Therefore, if one knows the direction in  
which the signal is sent out, one knows the  
direction from which the echo must return.  
1-1  
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1.5 Radar Wave Speed and  
Antenna Rotation Speed  
1.6 The Radar Display  
Targets are 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.  
The speed of the radar waves out to the  
target and back again as echoes is  
extremely fast compared to the speed of  
rotation of the antenna. By the time radar  
echoes have returned to the antenna, the  
amount of antenna rotation after initial  
transmission of the radar pulse is  
extremely small.  
With a continuous display of the images of  
targets, the motion of the transmitting ship  
is also displayed.  
Heading marker  
Targets  
Range and bearing  
of a target, relative  
to own ship, are  
A
D
A
D
readable on the PPI.  
B
B
C
C
Own ship  
in center  
Own ship  
(radar)  
(A) Bird's eye view of situation  
(B) Radar picture of (A)  
Figure 1-1 How radar works  
1-2  
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2. OPERATION  
2.1 Control Description  
Omnipad  
Shifts cursor, VRM  
and EBL; selects  
items and options  
on menu.  
Registers selection  
on menus.  
ENT  
MENU  
Opens/closes menus.  
HM  
OFF  
Adjusts GAIN,  
STC, A.C RAIN  
and FTC.  
ECHO  
Erases heading marker;  
selects cursor data (Lat/Long, R/B);  
outputs cursor position.  
Selects radar range.  
RANGE  
BRILL  
VRM  
TONE  
EBL  
Adjusts display brilliance.  
Turns the VRM on/off.  
Adjusts display  
tone.  
Turns the EBL  
on/off.  
Plots targets' trails.  
RINGS  
TRAIL  
Turns the range  
rings on/off.  
OFF  
CENTER  
GUARD  
Off centers  
the display.  
Sets guard  
zone area.  
DISP  
MODE  
ST-BY  
TX  
Sets radar in stand-by;  
transmits radar pulse.  
Selects display mode;  
erases heading error  
indication.  
Turns power on/off.  
POWER  
Figure 2-1 Control panel  
2-1  
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2.2 Display Indications and Markers  
Heading (requires  
heading data)  
Echo trail, AUTO tuning  
Range  
Echo trail elapsed time,  
echo trail time, tuning  
indicator  
AUTO  
HDG 326.8˚  
NM  
TRAIL  
0:00  
15S  
G ( IN )  
FTC1  
1.5  
Range ring interval  
0.5  
CU  
Presentation mode  
Off center  
Guard zone  
OFF  
CENTER  
ES  
IR  
FTC  
SP  
Pulsewidth  
Heading marker  
(rain clutter suppressor)  
Echo stretch  
Interference rejector  
Guard zone  
area  
Range rings  
Cursor  
EBL  
VRM  
Range and bearing to  
cursor or cursor position in  
latitude and longitude may  
be displayed by pressing  
the [HM OFF] key.  
VRM  
EBL  
+ CURSOR  
0.675NM 232.5˚R 0.681NM 308.7˚R  
}
EBL  
bearing  
Cursor  
range  
Cursor  
VRM  
range  
bearing  
Figure 2-2 Display indications  
Note: When the power is reapplied within a  
certain amount of time and circuits  
remain charged, the warmup process  
is skipped—you can transmit without  
one and a half minutes st-by time.  
2.3 Turning the Radar On and  
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.  
!
WARNING  
The radar antenna emits high frequency radio  
radiation which can be harmful, particularly to  
your eyes. Never look directly at the antenna  
from a distance of less than three feet when  
the radar is in operation. Always make sure  
no one is near the antenna before turning on  
the radar.  
2-2  
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Note: When the heading signal is lost, the  
HDG readout at the top of the screen  
shows ***.*. This warning stays on  
when the heading signal is restored  
to warn the operator that the readout  
may be unreliable. After confirming  
the heading readout (if necessary,  
adjust it), the warning may be erased  
by pressing the [DISP MODE] key.  
Tips for selecting the range  
• When navigating in or around crowded  
harbors, select a short range to watch  
for possible 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.  
2.4 Transmitting  
2.6 Adjusting LCD  
Backlighting and Display  
Tone  
After the power is turned on and the  
magnetron has warmed up, ST-BY (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.  
The [BRILL] key adjusts the LCD  
backlighting in eight levels, including off.  
The [TONE] key adjusts the tone (contrast)  
of the display in 32 levels, including off.  
Press the [ST-BY TX] key to transmit.  
When transmitting, any echoes reflected  
from targets appear on the display. This  
radar displays echoes in four tones of gray  
according to echo strength.  
Procedure  
1. Press the [BRILL] key (or [TONE] key).  
The display shown in Figure 2-3  
appears.  
BRILL  
UP  
When you won’t be using the radar for an  
extended period but want to keep it in a  
state of readiness, press the [ST-BY TX]  
key to set the radar in stand-by.  
TONE  
DOWN  
TONE  
UP  
Item selected  
for adjustment  
BRILL  
DOWN  
Tone  
setting  
19  
7
2.5 Selecting the Range  
LCD brilliance  
setting  
<MENU> TO EXIT  
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.  
Figure 2-3 Display for adjustment of  
brilliance and tone  
2. Press the [BRILL] key (or [TONE] key)  
to set level. For fine adjustment, press  
omnipad at 12 o'clock/6 o'clock for  
brilliance and 3 o'clock/9 o'clock for  
tone.  
Procedure  
Press the [– RANGE +] key. The range and  
range ring interval appear at the top left  
corner on the display.  
2-3  
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2. Press the omnipad at 6 o’clock/12  
o’clock to select item to adjust. Current  
selection is circumscribed by dashed  
rectangle.  
2.7 Adjusting Control Panel  
Illumination  
Procedure  
1. Press the [MENU] key.  
3. Press the [ENT] key.  
2. Press the omnipad at 6 o’clock to  
select Backlight/Brilliance and press  
the [ENT] key.  
4. Press the omnipad at 3 o’clock/9  
o’clock to set level.  
5. Press the [ECHO] key to finish.  
3. Press the omnipad at 6 o’clock to  
select Panel.  
How to adjust the GAIN (sensitivity)  
4. Press the omnipad at 3 o’clock/9  
o’clock to select illumination level; 4 is  
the highest.  
The GAIN works in precisely the same  
manner as the volume control of a  
broadcast receiver, amplifying the signals  
received.  
5. Press the [ENT] key followed by the  
[MENU] key.  
You can adjust the GAIN automatically or  
manually. If you select AUTO, the GAIN  
automatically adjusted. The range of the  
GAIN adjustment is from 1 to 3; 3 is the  
highest. For manual adjustment, adjust the  
sensitivity on the highest range—the  
background noise is clearer on that range.  
The range of GAIN adjustment is from 01  
to 41. The proper setting is such that the  
background noise is just visible on the  
screen. If you set up for too little GAIN,  
weak echoes may be missed.  
2.8 Adjusting GAIN, STC, A.C  
RAIN and FTC  
General procedure  
The [ECHO] key enables adjustment of the  
GAIN, STC, A.C RAIN and FTC.  
1. Press the [ECHO] key. The following  
display appears.  
Select auto or manual by  
pressing the omnipad at  
6 o'clock or 12 o'clock and  
pressing [ENT] key.  
On the contrary excessive GAIN 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.  
AUTO  
[
[
MAN  
01  
GAIN◆  
Item selected  
for adjustment  
◆
AUTO 1 2 3  
MAN  
STC  
Select auto or  
manual by  
A.C  
RAIN  
FTC  
00  
0 1 2  
pressing the  
omnipad at  
6 o'clock or  
12 o'clock and  
pressing [ENT]  
key.  
01  
ECHO KEY  
TO EXIT  
Select item/option  
by pressing appropriate  
omnipad arrow.  
Current level  
Figure 2-4 Display for adjustment of GAIN,  
STC, A.C RAIN and FTC  
2-4  
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How to adjust STC (suppressing  
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  
antenna 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  
left-hand figure in Figure 2-5).  
Sea clutter at  
display center  
STC adjusted;  
sea clutter suppressed.  
Figure 2-5 Effect of STC  
How to adjust A.C RAIN and FTC  
(suppressing rain clutter)  
The STC reduces the amplification of  
echoes at short ranges (where clutter is the  
greatest) and progressively increases  
amplification as the range increases, so  
amplification will be normal at those ranges  
where there is no sea clutter. The control is  
effective up to about 4 miles.  
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 2-6 shows the  
appearance of rain clutter on the display.  
STC can be adjusted automatically or  
manually. If you select AUTO, the STC  
automatically adjusted. The range of STC  
adjustment is from 1 to 3; 3 is the highest.  
For manual adjustment, first adjust the gain  
and then transmit on short range. The  
range of STC adjustment is from 00 to 50.  
Adjust the STC level such that the clutter is  
broken up into small dots, and small targets  
become distinguishable. If the setting 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 so clutter has  
Adjusting A.C RAIN  
When rain clutter masks echoes over a  
wide range, raise the A.C RAIN slightly to  
distinguish targets from the clutter.  
disappeared to leeward, but a little is still  
visible windward.  
Appearance of  
rain clutter  
A.C RAIN adjusted;  
rain clutter suppressed.  
If there is no clutter visible on the display,  
turn off the circuit.  
Figure 2-6 Effect of A.C RAIN  
2-5  
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Adjusting FTC  
Manual tuning  
To suppress rain clutter from heavy storms  
or scattered rain clutter, adjust the FTC  
among 0, 1 and 2 (0 is off). The FTC circuit  
splits up these unwanted echoes into a  
speckled pattern, making recognition of  
solid targets easier. FTC and selected level  
appear at the top right-hand corner of the  
display when the circuit is turned on.  
The default tuning method is automatic. To  
switch to manual tuning;  
1. Press the [MENU] key to open the  
menu.  
2. Press the omnipad at 6 o’clock to  
select Tuning.  
3. Press the omnipad at 3 o’clock to  
select MANUAL.  
Note: In addition to reducing clutter, the  
FTC 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  
required.  
4. Press the [ENT] key followed by the  
[MENU] key.  
How to tune manually  
While pressing and holding down the [HM  
OFF] key, press the 9 o'clock or 3 o'clock  
position on the omnipad to tune. Tune to  
show the longest tuning indicator.  
2.9 Tuning the Receiver  
2.10 Measuring the Range  
The receiver can be tuned automatically or  
manually. For automatic tuning the receiver  
is tuned each time you switch from stand-  
by to transmit. For manual tuning, the  
receiver is properly tuned when the longest  
tuning indicator appears. (However, the  
length of the indicator changes with the  
number of radar echoes, range and other  
factors.)  
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 rings  
Press the [RINGS] key to display the range  
rings. Count the number of rings between  
the center of the display and the target.  
Check the range ring interval (at the top left  
corner) and judge the distance of the echo  
from the inner edge of the nearest ring.  
Tuning  
indicator  
AUTO  
1.5NM  
0.5  
By cursor  
Figure 2-7 Tuning indicator  
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 of the  
display.  
Note:When you switch from manual to  
automatic, wait 4 seconds before  
closing the MENU. Otherwise  
automatic tuning may not work  
properly.  
2-6  
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By VRM  
2.11 Measuring the Bearing  
1. Press the [VRM] key to display the  
VRM.  
There are two ways to measure the bearing  
to a target: by the cursor, and by the EBL  
(Electronic Bearing Line).  
2. Press the omnipad to place the VRM  
on the inside edge of the target.  
By cursor  
3. Check the VRM readout at the bottom  
left-hand corner of the display to find  
the range to the target.  
Operate the omnipad to bisect the target  
with the cursor intersection. The bearing to  
the target appears at the bottom right-hand  
corner of the display.  
Note: The VRM is automatically anchored  
if the omnipad is not operated within  
about 10 seconds.  
By EBL  
To erase the VRM, press and hold down  
the [VRM] key for about two seconds.  
1. Press the [EBL] key to display the EBL.  
1.5NM  
2. Press the omnipad to bisect the target  
with the EBL.  
0.5  
3. Check the EBL readout at the bottom  
left-hand corner of the display to find  
the bearing to the target.  
Target  
VRM  
Note: The EBL is automatically anchored if  
the omnipad is not operated within  
about 10 seconds.  
To erase the EBL, press and hold down  
the [EBL] key for about two seconds.  
1.5NM  
0.5  
VRM  
+ CURSOR  
VRM  
range  
0.675NM
0.675NM 308.7˚R  
Target  
EBL  
Figure 2-8 Measuring range by the VRM  
EBL  
+ CURSOR  
300.1˚R  
0.675NM 300.1˚R  
EBL  
bearing  
Figure 2-9 Measuring bearing by the EBL  
2-7  
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Tips for measuring the bearing  
2.12 Menu Operation  
• Bearing measurements of smaller  
targets are more accurate; the center of  
larger target echoes is not as easily  
identified.  
The menu, consisting of six sub menus,  
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 and options on the menu with the  
omnipad.  
• 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.  
Basic menu operation  
1. Press the [MENU] key to open the main  
menu.  
◆ MAIN MENU ◆  
Select item by ◆◆ keys  
and press ENT key.  
1. Backlight/Brilliance  
2. P/L, IR, NR & Radar Mode  
3. Nav Data  
Target on Collision course with your  
vessel?  
4. Mode & Function  
5. Tuning  
AUTO MANUAL  
6. Self Check  
7. Installation Setup 1  
You can determine if a target might be  
on a collision course with your vessel by  
placing the EBL on the target. If it tracks  
along the EBL as it approaches the  
screen center it may be on a collision  
course with your vessel.  
. . . . . . . . . . . . . . . . . . .  
Press HM-OFF to temporarily  
hide menu.  
<Press MENU key to escape>  
Figure 2-10 Main menu  
2. Press the omnipad at 6 o’clock/12  
o’clock to select menu and press the  
[ENT] key.  
3. Press the omnipad at 6 o’clock/12  
o’clock to select a menu item.  
4. Press the omnipad at 3 o’clock/9  
o’clock to select an option.  
5. Press the [ENT] key to register  
selection.  
6. Press the [MENU] key to close the  
menu.  
2-8  
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Menu description  
Table 2-1 Menu description  
Menu  
Function  
1. Selects control panel backlighting; four is  
maximum backlighting.  
2. Selects brilliance for echo trails and  
markers; two is maximum brilliance.  
◆ BACKLIGHT/BRILLIANCE MENU ◆  
Select item and option  
by ◆◆keys.  
1. Panel  
1 2 3 4  
1 2  
2. Echo Trail  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Press HM-OFF to temporarily  
hide menu.  
<Press MENU for main menu.>  
1. Selects pulselength for 1.5 and 3 mile  
ranges.  
◆ P/L, IR, NR & Radar Mode ◆  
Select item and option  
2. Selects radar interference rejector level; 3  
provides highest degree of rejection.  
3. Turns noise rejector on/off.  
4. Turns echo stretch on/off.  
5. Selects presentation mode for CU or  
WPT-UP.  
by ◆◆keys.  
1. Pulselength  
2. Int Reject  
3. Noise Reject  
4. Echo Stretch  
5. Radar Mode  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Press HM-OFF to temporarily  
hide menu.  
SHORT LONG  
OFF 1 2 3  
OFF ON  
OFF ON  
CU WPT-UP  
<Press MENU for main menu.>  
1. Selects navigator among GPS, Loran C and  
all navigators available. In the "ALL" setting  
the radar selects a navigator in order of  
navigator accuracy–GPS, Loran and other.  
2. Turns navigation data display on/off.  
3. Selects position display format; latitude and  
longitude or Loran C TDs.  
◆ NAV DATA MENU ◆  
Select item and option  
by ◆◆keys.  
1. Navigator  
ALL GPS LC  
OFF ON  
2. Nav Data Disp  
3. Pos Disp Mode  
4. Depth Unit  
L/L TD  
M FA FT  
˚C ˚F  
NORM NAV  
4. Selects unit of measurement for depth;  
meters, feet or fathoms.  
5. Temp Unit  
6. STBY Display  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Press HM-OFF to temporarily  
hide menu.  
5. Selects unit of water temperature  
measurement; ˚C or ˚F.  
6. Selects what to display during stand-by;  
navigation data (requires navigation input)  
and "STBY".  
<Press MENU for main menu.>  
1. Selects window display format; zoom or  
wide.  
◆ MODE & FUNCTION MENU ◆  
Select item and option  
2. Selects watchman interval among 5 min,  
10 min and 20 min.  
by ◆◆keys.  
Zoom Wide  
OFF 5' 10' 20'  
IN OUT  
1. Window Display  
2. Watchman  
3. Alarm Mode  
4. VRM Unit  
5. EBL Ref  
3. Selects alarm mode; IN (alarm to targets  
entering the guard zone, or OUT (alarm to  
targets exiting the guard zone.  
4. Selects VRM unit; nm, km or sm.  
5. Selects EBL reference; relative to the  
ship's heading or true.  
NM KM SM  
REL TRUE  
1/8 1/4 1/2 3/4 1 1.5  
6. Range  
2 3 4 6 8 12 16 24 36 48  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Press HM-OFF to temporarily  
hide menu.  
6. Selects ranges to use. (At least two are  
selected.)  
Select range to enable (disable) and press  
[ENT] key.  
<Press MENU for main menu.>  
Tuning  
Self Check  
Selects AUTO or MANUAL tuning.  
Checks the radar system for proper operation.  
Default settings shown in reverse video.  
*
2-9  
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2.13 Selecting the Display  
Mode  
Each time the key is pressed the display  
mode changes in one of the sequences  
shown below, depending on equipment  
connected and menu settings.  
The display mode may be selected with the  
[DISP MODE] key. Four modes are  
available (with navigation input): Normal,  
Normal + Window, Normal + Nav Data, and  
Normal + Window + Nav Data.  
Window Display  
Nav Display  
WIDE / ZOOM  
ON OFF  
/
ZOOM  
Window display  
(Zoom or Wide)  
VRM  
EBL  
+CURSOR  
***.**NM ***.*˚ R  
VRM  
EBL  
+CURSOR  
***.**NM ***.*˚ R  
**.** NM ***.*˚R  
**.** NM ***.*˚R  
Normal  
Normal + Window  
Window Display  
Nav Display  
WIDE / ZOOM  
ON OFF  
/
ZOOM  
Nav data  
VRM  
EBL  
+CURSOR  
***.**NM ***.*˚ R  
VRM  
EBL  
+CURSOR  
***.**NM ***.*˚ R  
**.** NM ***.*˚R  
**.** NM ***.*˚R  
Normal + Nav Data  
Normal + Window + Nav Data  
Figure 2-11 Display modes  
2-10  
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2.14 The Window Display  
3. Press the [ENT] key to confirm the  
zoom area in the window display. The  
area selector becomes a dashed circle  
and the cursor can be moved  
independently.  
The window display appears at the bottom  
left (or right) 1/4 of the display. Two types of  
window displays are available: zoom and  
wide. Zoom doubles the size of the area  
selected by the operator, and wide (range-  
up) compresses and displays the entire  
radar picture from the next higher range.  
To reselect area to zoom, press [ENT] or  
[DISP MODE] and follow steps 2 and 3.  
Area selector (1/4 or 1/3 of range)  
Note 1: The zoom display does not  
function on the 0.125 and 0.25 nm  
ranges.  
Note 2: The wide display does not function  
Window  
display  
area  
on the 48 nm range.  
Zoom  
Zoom  
VRM  
VRM EBL  
**.** NM ***.*˚R  
+CURSOR  
***.**NM ***.*˚ R  
EBL  
**.** NM ***.*˚R  
+CURSOR  
***.**NM ***.*˚ R  
Selecting the type of window  
display  
(2) Use the omnipad  
to select area to zoom  
and press [ENT].  
(1) Press [DISP MODE]  
to select the window  
display.  
1. Press the [MENU] key.  
Figure 2-12 How to select  
the area to zoom  
2. Press the omnipad at 6 o’clock to  
select Mode & Function and press the  
[ENT] key.  
3. Press the omnipad at 6 o’clock to  
select Window Display to Zoom or  
Wide as appropriate.  
Wide display  
The entire picture on  
the next higher range.  
4. Press the [ENT] key followed by the  
[MENU] key.  
WIDE  
VRM  
**.** NM ***.*˚R  
EBL  
+CURSOR  
***.**NM ***.*˚ R  
Selecting the area for the zoom  
picture  
Figure 2-13 Example of wide display  
1. Press the [DISP MODE] key to select  
the window display. The area selector, a  
solid circle, appears.  
2. Use the omnipad to place the area  
selector on the area to zoom.  
Note: When you place the area selector  
behind the window display, the  
window display shifts right (or left) so  
you may view the circle cursor.  
2-11  
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WPT-UP (waypoint-up)  
2.15 Selecting the  
Presentation Mode  
An azimuth stabilized display in which the  
line connecting the center with the top of  
the display indicates the bearing to the  
“TO” waypoint, which is selected on the  
navigational equipment connected to the  
radar. When navigating a route and own  
ship enters the arrival zone of a waypoint,  
the radar displays the bearing to the next  
“TO” waypoint.  
This radar provides four presentation  
modes: head-up, course-up (course-up or  
waypoint-up; selectable on menu), north-  
up and true motion (requires heading  
sensor). Press the [DISP MODE] and [HM  
OFF] keys together to select a presentation  
mode. Each time the keys are pressed, if  
heading signal is input to the radar, the  
presentation mode changes in the  
Procedure  
sequence of HU, CU (or WU), NU, TM. If  
there is no heading signal input to the radar,  
the presentation mode is always HU.  
1. Press the [MENU] key to open the  
menu.  
2. Press the omnipad at 6 o’clock to  
select 2. P/L, IR, NR & Radar Mode.  
Note: TM does not function on the 48 nm  
range.  
3. Press the [ENT] key.  
CU  
(course-up)  
NU  
TM  
HU  
(head-up)  
4. Press the omnipad at 6 o’clock to  
select Radar Mode.  
WPT-UP  
(waypoint-up)  
(north-up) (true motion)  
5. Press the omnipad at 3 o’clock/9  
o’clock to select the option CU or  
WPT-UP as desired.  
Selecting course-up mode for CU  
or WPT-UP  
6. Press the [ENT] key followed by the  
[MENU] key.  
You may select WPT-UP instead of CU on  
the menu.  
CU (course-up)  
2.16 Guard Alarm  
An azimuth stabilized display in which a  
line connecting the center with the top of  
the display indicates own ship’s intended  
course (namely, own ship’s previous  
heading just before this mode has been  
selected).  
The guard alarm allows the operator to set  
the desired range and bearing for a guard  
zone. When ships, islands, landmasses,  
etc. enter (or exit, depending on type of  
guard zone in use) the guard zone an  
audible alarm sounds to call the operator’s  
attention. The alarm is very effective as an  
anticollision aid when using an autopilot or  
navigating in narrow channels.  
Target pips are painted at their measured  
distances and in their directions relative to  
the intended course which is maintained at  
the 0-degree position while the heading  
line moves in accordance with ship’s  
yawing and course change. This mode is  
useful to avoid smearing of picture during  
course change.  
2-12  
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Setting the guard zone  
CAUTION  
1. Mentally create the guard zone you  
want to display. See Figure 2-15 (1).  
The guard alarm is a useful anti-collision aid,  
but does not relieve the operator of the  
responsibility to also keep a visual lookout  
for possible collision situations. The alarm  
should never be used as the sole means for  
detecting possible collision situations.  
2. Operate the omnipad to set cursor on  
top (bottom) left edge of the guard zone.  
Press the [GUARD] key. *G (IN) (or G  
(OUT)), with asterisk blinking, appears  
at the top right-hand corner on the  
display. (The asterisk indicates the  
guard zone is partially set.) See Figure  
2-15 (2).  
Selecting guard zone type  
The guard alarm can be set to sound on  
targets entering (guard in) or exiting (guard  
out) the guard zone. Select type of guard  
zone as follows.  
3. Operate the omnipad to set cursor on  
bottom (top) right edge of the guard  
zone and press the [GUARD] key. The  
asterisk disappears. See Figure 2-15  
(3).  
1. Press the [MENU] key to display the  
menu.  
2. Press the omnipad at 6 o’clock to  
select Mode & Function and press the  
[ENT] key.  
4. Guard zone appears on the display.  
See Figure 2-15 (4).  
3. Press the omnipad at 6 o’clock to  
select Alarm Mode.  
Silencing the audible alarm  
Any ships, landmasses, etc. coming into  
(or going out of) the guard zone will trigger  
the audible alarm and display the guard  
zone in reverse video. You can silence the  
alarm by pressing the [GUARD] key. When  
this is done, G (ACKN) replaces G (IN) (or  
G (OUT)).  
4. Press the omnipad at 3 o’clock/9  
o’clock to select IN or OUT as  
appropriate.  
5. Press the [ENT] key followed by the  
[MENU] key.  
Press the [GUARD] key again to reactivate  
the alarm. G (IN) (or G (OUT)) replaces G  
(ACKN).  
Dashed line:  
no alarm  
Guard  
zone  
IN ALARM  
OUT ALARM  
Figure 2-14 In and out alarms  
2-13  
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Canceling the guard zone  
2.17 Suppressing Radar  
Interference  
Press and hold down the [GUARD] key  
until the guard zone disappears.  
Radar interference may occur when near  
another shipborne radar operating in the  
same frequency band as your radar. Its on-  
screen 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 2-16  
illustrates interference in the form of curved  
spokes. Interference effects are  
Notes on the guard alarm  
• When the radar range is less than one  
half of the guard zone range, the guard  
zone disappears from the display and  
G (IN) (or G (OUT)) is displayed in  
reverse video. If this happens, raise the  
range to redisplay the guard zone.  
distinguishable from normal echoes  
because they do not appear in the same  
place on successive rotations of the  
antenna.  
• A target echo does not always mean a  
landmass, reef, ships or surface objects  
but can imply returns from sea surface  
or precipitation. As the level of these  
returns varies with environment, the  
operator should properly adjust the STC,  
GAIN (sensitivity), A. C RAIN and FTC  
to be sure the alarm system does not  
overlook target echoes.  
Figure 2-16 Radar interference  
Asterisk blinking  
Four levels of interference are available,  
including off. 3 provides the highest level of  
rejection.  
Guard zone  
to set  
* G (IN)  
Procedure  
Drag cursor  
here.  
1. Press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select P/L, IR, NR & Radar Mode and  
press the [ENT] key.  
(1) Mentally create  
the guard zone to set.  
(2) Drag cursor to  
top left corner of  
zone and press  
[GUARD].  
3. Press the omnipad at 6 o’clock to  
select Int Reject.  
G (IN)  
G (IN)  
4. Press the omnipad at 3 o’clock/9  
o’clock to select level desired; 3  
provides the greatest degree of  
interference rejection.  
Guard  
zone  
Drag cursor  
here.  
5. Press [ENT] and [MENU] keys.  
(4) Guard zone  
completed.  
(3) Drag cursor to  
bottom right corner  
of zone and press  
[GUARD].  
IR appears at the top right corner on the  
display when the interference rejection  
circuit is turned on.  
Figure 2-15 How to set a guard zone  
2-14  
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2.18 Suppressing Noise  
Interference  
4. Press the omnipad at 3 o’clock/9  
o’clock to select SHORT or LONG as  
appropriate.  
Noise interference appears on the screen  
as many bright dots. These dots can be  
suppressed by turning on the noise rejector.  
Note however that there are some forms of  
noise interference which this radar cannot  
suppress.  
5. Press [ENT] and [MENU] keys.  
SP or MP for 1.5 NM range, or MP or LP for  
3 NM range appears at the upper left-hand  
corner.  
2.20 Off Centering the Display  
Procedure  
Note: This function is not available on the  
1. Press the [MENU] key.  
48 nm range.  
2. Press the omnipad at 6 o’clock to  
select P/L, IR, NR & Radar Mode and  
press the [ENT] key.  
Your vessel’s position can be shifted  
anywhere in the effective display area. The  
primary advantage of the off centered  
display is that for any range setting, the  
view ahead of your vessel can be extended  
without changing the range or size of  
targets.  
3. Press the omnipad at 6 o’clock to  
select Noise Reject.  
4. Press the omnipad at 3 o’clock/9  
o’clock to select ON or OFF as  
appropriate.  
Procedure  
5. Press the [ENT] key followed by the  
[MENU] key.  
1. Locate the cursor where you want to  
the screen center to be.  
2.19 Selecting Pulselength  
2. Press the [OFF CENTER] key.  
OFF CENTER appears at the top left  
corner on the display when the display is  
off centered.  
Pulselength is the transmission time of a  
single radar pulse. The longer the  
pulselength the greater the detection range  
capability, however range accuracy and  
range resolution are reduced.  
3. To cancel the off center display, press  
the [OFF CENTER] key again.  
Pulselength can be selected to short or  
long on the 1.5 and 3 nautical mile ranges.  
1. Press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select P/L, IR, NR & Radar Mode and  
press the [ENT] key.  
Cursor  
Cursor  
(2) Press [OFF CENTER] key;  
cursor location becomes  
own ship's position.  
(1) Place cursor  
where desired.  
3. Press the omnipad at 6 o’clock to  
select Pulselength.  
Figure 2-17 Off centering the display  
2-15  
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Fixed time trails  
2.21 Echo Trails  
You can show the trails of targets in  
afterglow. This function is useful for alerting  
you to possible collision situations.  
When the elapsed time clock counts up to  
the trail time selected, the elapsed time  
display freezes. The oldest portions of trails  
are erased so only the latest trail, equal in  
length to the trail time selected, is shown.  
Then, trails start extending again. For  
example, the one minute trail time is  
selected. When the elapsed time display  
freezes at 60 seconds, all but the latest one  
minute of trails are erased and then trailing  
continues.  
Starting echo trail  
Press the [TRAIL] key to start the echo trail  
function. Afterglow starts extending from  
targets and "TRAIL" and the echo trail time  
appear at the top right-hand corner of the  
display. Press the key again within 3  
seconds to select a different trail time,  
among 15 sec, 30 sec, 1 min, 3 min, 6 min,  
15 min, 30 min, and continuous. In  
continuous plotting the time elapsed  
appears at the top right corner on the  
display.  
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, all  
trails are erased and then trailing is  
restarted.  
Note: If the range is changed, trails are  
painted anew with the newly selected  
range.  
Adjusting brilliance of afterglow  
The brilliance of the trails' afterglow can be  
set on the Backlight/Brilliance menu.  
1. Press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select Backlight/Brilliance and press  
the [ENT] key.  
True trails  
Relative trails  
Figure 2-18 Appearance of echo trails  
3. Press the omnipad at 6 o’clock to  
select Echo Trail.  
4. Select brilliance level, 1 or 2 as desired.  
2 is the highest level.  
5. Press the [ENT] key followed by the  
[MENU] key.  
Canceling echo trails  
Press the [TRAIL] key to erase the TRAIL  
indication.  
2-16  
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Setting up the nav data display  
2.22 Navigation Data Display  
1. Press the [MENU] key.  
Navigation data can be displayed at the  
screen bottom if this radar receives  
appropriate navigation input in NMEA 0183  
format. Navigation data includes  
2. Press the omnipad at 6 o’clock to  
select Nav Data and press the [ENT]  
key.  
• Position in latitude and longitude or  
◆ NAV DATA MENU ◆  
Loran-C time differences (TDs)  
Select item and option  
by ◆◆ keys.  
• Bearing and range to a waypoint  
1. Navigator  
ALL GPS LC  
OFF ON  
L/L TD  
M FA FT  
˚C ˚F  
2. Nav Data Disp  
3. Pos Disp Mode  
4. Depth Unit  
5. Temp Unit  
6. STBY Display  
selected on the navigator  
• Cross track error (XTE-the amount in  
nautical miles and the direction the  
vessel if off course)  
NORM NAV  
. . . . . . . . . . . . . . . . . . .  
Press HM-OFF to temporarily  
hide menu.  
• Depth  
• Speed  
<Press MENU for main menu.>  
If the navigation data includes the  
destination data, waypoint position is  
denoted on the radar display by a dashed  
ring.  
Figure 2-20 Nav data menu  
3. Press the omnipad at 6 o'clock to  
select Navigator.  
Waypoint position  
4. Press the omnipad at 3 o'clock/9  
o'clock to select ALL, GPS or LC as  
appropriate and press the [ENT] key.  
(Select ALL if several navigators are  
connected to the radar. In this case,  
position data is selected in order of  
GPS, Loran C and other.)  
AUTO  
HDG 326.8˚  
1.5NM  
0.5  
5. Press the omnipad at 6 o'clock to  
select Nav Data Disp.  
6. Press the omnipad at 3 o'clock/9  
o'clock to select ON or OFF as  
appropriate and press the [ENT] key.  
DEPTH  
XTE  
SPD  
350.0m  
0.05NML 30.0KT  
7. Press the omnipad at 6 o'clock to  
select Pos Disp Mode.  
WAYPOINT  
POSI L/L  
66˚ 04. 00N  
166˚ 04. 00E  
1.8NM  
25˚M  
VRM  
EBL  
+ CURSOR  
0.646 NM 308.7˚R  
8. Press the omnipad at 3 o'clock/9  
o'clock to select L/L (latitude and  
longitude) or TD (Loran C) as  
0.675NM 240.1˚R  
Figure 2-19 Sample nav data display  
appropriate and press the [ENT] key.  
9. Press the omnipad at 6 o'clock to  
select Depth Unit.  
2-17  
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10. Press the omnipad at 3 o'clock/9  
o'clock to select M (meters), FA  
(fathoms) or FT (feet) as desired and  
press the [ENT] key.  
Turning echo stretch on or off  
1. Press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select P/L, IR, NR & Radar Mode and  
press the [ENT] key.  
11. Press the omnipad at 6 o'clock to  
select Temp Unit.  
3. Press the omnipad at 6 o’clock to  
select Echo Stretch.  
12. Press the omnipad at 3 o'clock/9  
o'clock to select °C or °F as desired  
and press the [ENT] key.  
4. Press the omnipad at 3 o’clock/9  
o’clock to select ON or OFF as  
appropriate.  
13. Press the omnipad at 6 o'clock to  
select STBY Display.  
5. Press the [ENT] key followed by the  
[MENU] key. ES appears at the top  
right side on the display when the echo  
stretch feature is on.  
14. Press the omnipad at 3 o'clock/9  
o'clock to select NORM (navigational  
data is not displayed) or NAV  
(navigational data is displayed as  
desired) and press the [ENT] key.  
Note 1: 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  
15. Press the [MENU] key to escape.  
2.23 Echo Stretch (magnifying  
long range echoes)  
activating the echo stretch.  
Normally, the reflected echoes from long  
range targets appear on the display as  
weaker and smaller blips even though they  
are compensated by the radar’s internal  
circuitry. To stretch long range echoes, in  
the range direction, turn on the echo  
stretch function.  
Note 2: Echo stretch is inoperative on  
ranges from 0.125 to 0.5 nautical  
miles.  
Note 3: When the echo stretch function is  
selected, the equipment  
automatically selects interference  
rejection level #3 and turns on the  
noise rejector. These can be turned  
off via the menu if desired.  
Distant echo  
Echo stretch OFF  
Echo stretch ON  
Figure 2-21 Echo stretch  
2-18  
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2.24 Selecting Unit of  
2.26 Watchman  
How watchman works  
Measurement for Range  
The unit of measurement for the VRM and  
cursor can be nautical miles, kilometers, or  
statute miles. You may select unit desired  
as follows.  
The watchman function periodically  
transmits the radar for about one minute to  
check for targets in a guard zone. If it finds  
change in the zone from the previous  
transmission it sounds the aural alarm,  
cancels the watchman function, and  
1. Press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select Mode & Function and press the  
[ENT] key.  
transmits 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.  
3. Press the omnipad at 6 o’clock to  
select VRM Unit.  
Tx  
St-by  
Tx  
St-by  
4. Press the omnipad at 3 o’clock/9  
o’clock to select NM, KM, or SM as  
desired.  
1 min  
5, 10 or  
20 min  
1 min  
5, 10 or  
20 min  
Watchman  
starts.  
5. Press [ENT] followed by [MENU] key.  
Figure 2-22 How watchman works  
2.25 Selecting Bearing  
Reference  
Turning on watchman  
1. Create a guard zone (usually 360  
degrees) with the guard alarm function.  
Bearing can be displayed relative to ship’s  
heading (relative bearing) or relative to true  
north (true bearing) as follows. (True  
2. Press the [MENU] key.  
3. Press the omnipad at 6 o’clock to  
select Mode & Function and press the  
[ENT] key.  
bearing requires heading sensor input.)  
1. Press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select Mode & Function and press the  
[ENT] key.  
4. Press the omnipad at 6 o’clock to  
select Watchman.  
5. Press the omnipad at 3 o’clock/9  
o’clock to select watchman rest interval  
(amount of time until next rotation of  
antenna); 5 minutes, 10 minutes or 20  
minutes as desired.  
3. Press the omnipad at 6 o’clock to  
select EBL Ref.  
4. Press the omnipad at 3 o’clock/9  
o’clock to select REL(ATIVE) or TRUE  
as appropriate.  
6. Press the [ENT] key followed by the  
[MENU] key. Then, WATCHMAN  
appears, and the radar transmits for  
one minute and then goes into stand-  
by.  
5. Press the [ENT] key followed by the  
[MENU] key.  
2-19  
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Canceling watchman  
6. Repeat steps 4 and 5 to disable (or  
enable) other ranges.  
1. Press the [MENU] key.  
7. When finished, press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select Mode & Function and press the  
[ENT] key.  
2.29 Displaying Navigation  
Data During Stand-by  
3. Press the omnipad at 6 o’clock to  
select Watchman.  
Various navigation data can be displayed  
during stand-by. A barometer is built in this  
radar; atmospheric pressure appears, in  
graph form, on the navigation data display  
during stand-by. If your navigation aid can  
output data in NMEA 0183 data format,  
your vessel’s position in latitude and  
longitude, the range and bearing to  
4. Press the omnipad at 3 o’clock/9  
o’clock to select OFF.  
5. Press the [ENT] key followed by the  
[MENU] key.  
2.27 Erasing the Heading  
Marker  
waypoint, speed, course, date, time and  
cross track error may be input to this radar,  
and be seen in the bottom text area during  
stand-by. Further, with video sounder input,  
depth may be displayed, both digitally and  
in graph form.  
The heading marker continuously appears  
on the display and shows your vessel’s  
heading. When this mark obscures a target  
echo, you can temporarily erase it by  
pressing and holding down the [HM OFF]  
key. Release the key to redisplay the  
marker.  
CAUTION  
The barometer and depth displays are intended  
as reference. Any data displayed by them should  
be used with extreme caution.  
2.28 Deselecting Ranges  
This radar has 16 ranges, some which you  
may not require. You can deselect up to  
fourteen ranges as follows.  
Procedure  
1. Press the [MENU] key.  
1. Press the [MENU] key.  
2. Press the omnipad at 6 o’clock to  
select the Nav Data and press the  
[ENT] key.  
2. Press the omnipad at 6 o’clock to  
select Mode & Function and press the  
[ENT] key.  
3. Press the omnipad at 6 o’clock to  
select STBY Display.  
3. Select Range and press the [ENT] key.  
Active ranges appear in reverse video.  
4. Press the omnipad at 3 o’clock/9  
o’clock to select NAV and press the  
[ENT] key.  
4. Press the omnipad at 3 o’clock/9  
o’clock to select range to disable (or  
enable) and press the [ENT] key.  
Current selection is underlined.  
5. Press the [MENU] key.  
5. Press the [ENT] key.  
2-20  
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2.31 Displaying Cursor  
Position, Range and  
Bearing to Cursor  
Note 1: The depth display scale changes  
automatically with depth and the  
maximum depth is 1,000 meters.  
Note 2: The barometer display is updated  
hourly, thus the data shown may  
not be the latest.  
The cursor data indication at the bottom of  
the display can show cursor position in  
latitude and longitude or the range and  
bearing from own ship to the cursor. You  
can select the indication desired by  
pressing the [HM OFF] key.  
ST–BY  
(mbar/hPa)  
(MIN)  
2
1
0
1020  
1010  
1000  
990  
Navigation data is required to display  
latitude/longitude position.  
500  
1000  
(m)  
-12 -9 -6 -3  
(HOUR)  
BAROMETER  
DEPTH  
2.32 Visual Alarm Indications  
DATE  
TIME  
TEMP  
CRS  
This radar display various visual alarms to  
alert you to error.  
08.22  
15:19  
30.0˚C  
0.0˚M  
DEPTH  
827 m  
WAYPOINT  
XTE  
SPD  
0.6NM R 30.0KT  
Table 2-2 Visual alarm indications  
POSI L/L  
65˚43.98N  
165˚43.96E  
12.0NM 114.8˚R  
Error  
Visual alarm  
XTE  
XTE  
No heading pulse  
No bearing pulse  
HD SIG MISSING  
BRG SIG MISSING  
L
R
(NM) 0.5  
0.5  
1
0
1
Heading signal  
turned off  
***.* (appears as  
heading)  
Figure 2-23 Navigation data display during  
stand-by  
2.30 Outputting Cursor  
Position to Navigator  
The heading signal visual alarm may be  
cleared by pressing the [DISP MODE] key.  
Cursor position (NMEA0183 data sentence  
TLL) can be output to the navigator  
connected to this radar by pressing and  
holding down the [HM OFF] key.  
2-21  
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3. INTERPRETING THE DISPLAY  
Sub-refraction  
As an aid to navigation, radar can be a very  
valuable tool. No other electronic  
Sub-refraction is the reverse condition of  
super-refraction; a layer of cold air is above  
a layer of warm air. Radar waves bend  
upward and thus decrease the ranges at  
which targets may be detected.  
navigation aid can give you the ability to  
spot vessels coming at you in the fog, or  
tell you the location of the inlet to the  
harbor in the pitch black of night.  
To help you understand what your radar  
can (and cannot) do for you this chapter  
covers  
Radar horizon  
Radar is essentially a “line-of-sight”  
phenomenon. That means you have just  
about the same range to horizon with a  
radar as you do with your own eyes.  
However under normal atmospheric  
conditions, the radar horizon is 6% greater  
than the optical horizon. Therefore, if the  
target does not rise above the horizon the  
radar beam cannot be reflected from the  
target.  
• the characteristics of the radar wave  
• target properties and radar wave  
reflection  
• range and bearing resolution, and  
• false echoes.  
3.1 The Radar Wave and Radar  
Horizon  
How the radar wave travels  
The distance to the horizon from the  
antenna, under normal conditions, is  
calculated by the following formula.  
The radar wave tends to travel in straight  
lines at the speed of light. However, it is  
subject to bending or refraction in the  
atmosphere, the amount depending on  
region and density.  
Rmax = 2.2 × h1 + h2  
Where Rmax: Radar horizon (mile), h1:  
Antenna height (meters), h2: Target height  
(meters)  
Super-refraction  
Super-refraction is a condition in which  
there is an upper layer of warm dry air over  
a surface layer of cold, moist air. Radar  
waves bend downward and thus increase  
the ranges at which targets may be  
detected.  
D
Horizon  
h2  
Wave  
path  
h1  
Figure 3-1 Radar horizon  
3-1  
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3.2 Target Properties and  
Radar Wave Reflection  
3.3 Range Resolution  
Range resolution is a measure of the  
capability of a radar to display as separate  
pips the echoes received from two targets  
which are on the same bearing and are  
close together.  
Generally, larger targets can be seen on  
the radar display at greater ranges,  
provided line-of-sight exists between the  
scanner and target. However, a large target  
with poor reflecting properties may not be  
detected as easily as a smaller target with  
better reflecting properties. For example,  
you might expect a lighthouse to be a good  
radar target because of its size. In actuality  
the return echo is weak since the conical  
shape diffuses most of the radiated energy.  
The main factor which affects range  
resolution is pulselength. Two targets on  
the same bearing, close together, cannot  
be seen as two distinct echoes on the  
display unless they are separated by a  
distance greater than one-half the  
pulselength.  
Radar is able to display two  
A ship whose hull is made of conducting  
materials, such as steel, will return a  
relatively strong echo.  
Transmitted  
radar  
pulse  
distinct target echoes.  
Target  
On the other hand, hulls made from wood  
or fiberglass return much weaker echoes.  
Transmitted  
radar  
Vertical surfaces, such as a cliff, are good  
targets provided they face the radar.  
Conversely, horizontal and smooth  
surfaces such as mudbanks, sandy  
beaches, and gently sloping hills make  
poor targets because they disperse rather  
than reflect most of the energy that strikes  
them.  
Target  
pulse  
Radar cannot display targets as  
separate echoes because they  
are within the pulselength.  
Figure 3-2 Range resolution  
The strongest radar echoes known come  
from built-up areas, docks, etc., because  
these targets are less subject to changes in  
aspect. These types of targets have three  
flat, smooth surfaces mutually at right  
angles. Some radar buoys are arranged  
this way so as to deliberately increase their  
detection range.  
3.4 Bearing Resolution  
Bearing resolution is a measure of the  
capability of a radar to display as separate  
targets the echoes received from two  
targets which are at the same range and  
are close together.  
The principal factor which affects bearing  
resolution is horizontal beamwidth. Two  
targets at the same range must be  
separated by more than one beamwidth to  
appear as separate pips.  
3-2  
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True  
echo  
Radar is able to display two  
distinct target echoes.  
Target  
Horizontal  
beamwidth  
Direction of  
scanner rotation  
Target  
Target  
Own ship  
Multiple  
echo  
Horizontal  
beamwidth  
Figure 3-4 Multiple echoes  
Direction of  
scanner rotation  
Radar cannot display targets as  
separate echoes because they  
are within the beamwidth.  
Side-lobe echoes  
Every time the antenna rotates, some  
radiation escapes on each side of the  
beam-called “side-lobes.” If a target exists  
where it can be detected by the 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 3-5. 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 STC.  
Figure 3-3 Bearing resolution  
3.5 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.  
True echo  
Main-lobe  
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 3-4. Multiple reflection echoes can  
be reduced and often removed by  
Side-lobe  
Spurious  
target  
Antenna  
Figure 3-5 Side-lobe echoes  
decreasing the sensitivity or properly  
adjusting the STC.  
3-3  
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Indirect echoes  
Blind and shadow sectors  
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 3-6  
illustrates the effect of an indirect echo.  
Indirect echoes may be recognized as  
follows:  
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 3-7.  
Vessel taller  
than whart  
Mast, etc. in path  
of radar beam  
Wharf  
• they usually occur in a shadow sector  
• they appear on the bearing of the  
obstruction but at the range of the  
legitimate contact  
Wharf  
• when plotted, their movements are  
Blind sector  
(no echo)  
Size of blind sector  
depends on target  
size and range.  
usually abnormal, and  
• their shapes may indicate they are not  
direct echoes.  
Figure 3-7 Blind and shadow sectors  
Heading  
marker  
Target  
Direct  
path  
Indirect  
path  
Obstruction  
(mast, funnel,  
etc.)  
Antenna  
True  
echo  
Indirect  
echo  
Target  
Indirect  
path  
Direct  
path  
Heading  
marker  
True  
echo  
Own  
ship  
Bridge  
Indirect  
echo  
Indirect  
echo  
Figure 3-6 Indirect echoes  
3-4  
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Screen A:When SART  
is distant  
Screen B:When SART  
is close  
3.6 SART  
Lines of 12 dots  
are displayed in  
concentric arcs.  
Note: The SART (Search and Rescue  
Transponder) information below is  
excerpted from IMO SN/Circ 197  
Operation of Marine Radar for SART  
Detection.  
Radar antenna  
beamwidth  
Echo of SART  
24 NM  
Echo of  
SART  
1.5 NM  
Position of  
SART  
Own ship's  
position  
Own ship's  
position  
A Search and Rescue Transponder  
Position of  
SART  
SART mark  
length  
(SART) may be triggered by any X-Band (3  
cm) radar within a range of approximately  
8 nm. Each radar pulse received causes it  
to transmit a response which is swept  
repetitively across the complete radar  
frequency band. When interrogated, it first  
sweeps rapidly (0.4 µs) through the band  
before beginning a relatively slow sweep  
(7.5 µs) through the band back to the  
starting frequency. This process is  
Radar receiver  
bandwidth  
9500 MHz  
9200 MHz  
Sweep time  
7.5 µs  
95 µs  
Low speed sweep signal  
High speed sweep signal  
Sweep start  
Figure 3-8 Appearance of SART signal  
on the radar display  
repeated for a total of twelve complete  
cycles. At some point in each sweep, the  
SART frequency will match that of the  
interrogating radar and be within the pass  
band of the radar receiver. If the SART is  
within range, the frequency match during  
each of the 12 slow sweeps will produce a  
response on the radar display, thus a line  
of 12 dots equally spaced by about 0.64  
nautical miles will be shown.  
General procedure for detecting  
SART response  
1. Use the range scale of 6 or 12 nm as  
the spacing between the SART  
responses is about 0.6 nm (1125 m) to  
distinguish the SART.  
2. Turn off the automatic clutter  
suppression.  
3. Turn off the Interference Rejector.  
When the range to the SART is reduced to  
about 1 nm, the radar display may show  
also the 12 responses generated during  
the fast sweeps. These additional dot  
responses, which also are equally spaced  
by 0.64 nm, will be interspersed with the  
original line of 12 dots. They will appear  
slightly weaker and smaller than the  
original dots.  
General remarks on receiving  
SART  
SART range errors  
When responses from only the 12 low  
frequency sweeps are visible (when the  
SART is at a range greater than about 1  
nm), the position at which the first dot is  
displayed may be as much as 0.64 nm  
beyond the true position of the SART.  
When the range closes so that the fast  
sweep responses are seen also, the first of  
these will be no more than 150 meters  
beyond the true position.  
3-5  
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Radar bandwidth  
STC control  
This is normally matched to the radar  
pulselength and is usually switched with  
the range scale and the associated  
pulselength. Narrow bandwidths of 3-5  
MHz are used with long pulses on long  
range and wide bandwidths of 10-25 MHz  
with short pulses on short ranges.  
For optimum range SART detection, this  
control should be set to the minimum. Care  
should be exercised as a wanted target in  
sea clutter may be obscured. Note also that  
in clutter conditions the first few dots of the  
SART response may not be detectable,  
irrespective of the setting of the anti-clutter  
sea control. In this case, the position of the  
SART may be estimated by measuring 9.5  
nm miles from the furthest dot back  
Any radar bandwidth of less than 5 MHz  
will attenuate the SART signal slightly, so it  
is preferable to use a medium bandwidth to  
ensure optimum detection of the SART.  
towards own ship.  
Some sets have automatic/manual anti-  
clutter sea control facilities in which case  
the operator should switch to manual.  
Radar side lobes  
As the SART is approached, sidelobes  
from the radar antenna may show the  
SART responses as a series of arcs or  
concentric rings. These can be removed by  
the use of the anti-clutter sea control  
although it may be operationally useful to  
observe the sidelobes as they may be  
easier to detect in clutter conditions and  
also they will confirm that the SART is near  
to the ship.  
FTC control  
This should be used normally (to break up  
areas of rain) when trying to detect a SART  
response which, being a series of dots, is  
not affected by the action of the anti-clutter  
rain circuitry. Note that Racon responses,  
which are often in the form of a long flash,  
will be affected by the use of this control.  
Some sets have automatic/manual anti-  
clutter rain control facilities in which case  
the operator should switch to manual.  
GAIN  
For maximum range SART detection the  
normal gain setting for long range detection  
should be used, that is, with background  
noise speckle visible.  
When the range to the SART is reduced to  
about 1 nm, the radar display may show  
also the 12 responses generated during  
the fast sweeps. These additional dot  
responses, which also are equally spaced  
by 0.64 nm, will be interspersed with the  
original line of 12 dots. They will appear  
slightly weaker and smaller than the  
original dots.  
3-6  
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3.7 Racon (Radar Beacon)  
A racon is a radar transponder which emits  
a characteristic signal when triggered by a  
ship’s radar (usually only the 3 centimeter  
band). The signal may be emitted on the  
same frequency as that of the triggering  
radar, in which case it is superimposed on  
the ship's radar display automatically.  
The racon signal appears on the PPI as a  
radial line originating at a point just beyond  
the position of the radar beacon or as a  
Morse code signal (see figure below)  
displayed radially from just beyond the  
beacon.  
Racon  
Figure 3-9 Appearance of racon signal  
on the display  
3-7  
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4. MAINTENANCE &  
TROUBLESHOOTING  
This chapter tells you how to keep your  
4.1 Preventative  
radar in good working order. Before  
reviewing this chapter please read the  
safety information which follows.  
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.  
WARNING  
Only qualified personnel should  
work inside the equipment.  
Do not open the equipment.  
RF RADIATION HAZARD  
The radar antenna emits high  
frequency radio radiation which  
A maintenance program should be  
established and should at least include the  
items listed in Table 4-1.  
can be harmful, particularly to your eyes.  
Never look directly into the antenna from a  
distance of less than 1 m 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.  
Table 4-1 Recommended maintenance program  
Item  
Check point  
Period  
Remarks  
Exposed  
nuts and  
bolts on  
Check for corrorded or loosened nuts  
and bolts. If necessary, clean and  
repaint them thickly. Replace them if  
3 to 6  
months  
Sealing compound may be used  
instead of paint. Apply a small  
amount of grease between nuts  
and bolts for easy removal in future.  
antenna unit heavily corroded.  
Antenna  
radiator  
Check for dirt and cracks on radiator  
Do not use plastic solvent (acetone)  
for cleaning. If you need to remove  
ice from antenna unit, use a  
wooden hammer or plastic head  
hammer. Crack on the unit may  
cause water ingress, causing  
surface. thick dirt should be wiped off  
with soft cloth dampened with fresh  
water. If a crack is found, apply a slight  
amount of sealing compound or  
adhesive as a temporary remedy, then  
call for repair.  
serious damages to internal circuits.  
Terminal  
strips and  
plugs in  
Open antenna cover to check terminal  
strip and plug connections inside. Also  
check the rubber gasket of antenna  
When closing antenna covers in  
position, be careful not to catch  
loose wires between covers and  
unit.  
antenna unit covers for deterioration.  
LCD The LCD will, in time, accumulate a  
Do not use chemical cleaners to  
clean any part of the display unit;  
they can remove paint and  
markings.  
coating of dust which tends to dim the  
picture. Wipe LCD lightly with a soft  
cloth.  
Display unit Check for tight connection and  
6 months  
to 1 year  
If corroded, contact your dealer  
for replacement.  
connectors  
corrosion.  
4-1  
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4.2 Replacing the Fuse  
4.3 Troubleshooting  
The fuse in the power cable protects the  
equipment against reverse polarity of ship’s  
mains, overcurrent, 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.  
Table 4-2 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.  
24/32 VDC  
12 VDC  
:5 A fuse  
:10 A fuse  
Table 4-2 Troubleshooting table  
If...  
Then...  
But...  
you pressed the  
[POWER] key to  
turn on the radar  
try adjusting the control panel backlighting  
on the Brilliance/Backlighting menu.  
battery may have discharged.  
the control panel does not  
light  
check fuse in power cable.  
try adjusting the tone.  
(Extreme ambient temperature may affect  
display tone.)  
nothing appears on the  
display or display contrast  
is poor  
request service.  
characters are distorted  
the radar has  
warmed up and you  
pressed the  
the problem may be in antenna unit.  
Request service.  
the antenna does not  
rotate  
[ST-BYTX] key to  
transmit  
have a qualified technician check the set.  
check signal cable for damage.  
characters and indications  
are abnormal  
you have adjusted  
the gain with FTC  
and STC off  
neither noise nor targets  
appear (indications and  
markers do)  
check signal cable for damage.  
neither indications nor  
markers appear  
(noise and targets do)  
the problem may be in the antenna unit.  
Request service.  
the sweep (radial line  
sweeping around the  
display) is not  
synchronized with  
antenna rotation  
request service.  
there is no change in  
sensitivity.  
a key is pressed  
key may be faulty. Request service.  
nothing happens  
4-2  
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4.4 Test  
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.  
The self test facility checks the keyboard,  
ROM and RAM for proper operation. You  
may run the test as follows.  
NMEA data can be displayed on the test  
screen as follows;  
1. Press the [MENU] key.  
2. Select Self Check. The following  
display appears.  
1. Press the [+] key. NMEA data appears  
on the upper half of the screen.  
2. Press the [TONE] key to select input  
source; NAV, HDG or E/S.  
3. To display the NMEA data over the  
entire screen, press the [-] key three  
times.  
4. To erase the NMEA data, press the [+]  
key.  
M851  
SELF TEST  
KEY Board TEST :  
Press each key and  
note that the cor-  
responding key on  
the screen turns  
black.  
4.5 Replacing the  
Magnetron  
When the magnetron has expired distant  
targets cannot be seen on the display. When  
you feel long range performance has  
Prog. No. 03591371**  
ROM : OK  
decreased contact a FURUNO agent or  
dealer about replacement of the magnetron.  
RAM : OK  
On Hours 000008.3H  
Tx Hours 000007.9H  
Magnetron type: MG5248  
(Code No. 000-116-121)  
<MENU> = MAIN MENU  
**: Program version no.  
Figure 4-1 Test screen  
3. To check the keyboard, press each key  
except the [MENU] key. Its  
corresponding location on the display  
lights in black if the key is operating  
properly.  
4. To escape from the test, press the  
[MENU] key.  
4-3  
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MENU TREE  
[MENU] key  
1. Backlight/Brilliance  
1. Panel (1, 2, 3, 4)  
2. Echo trail (1, 2)  
2. P/L, IR, NR & Radar Mode  
1. Pulselength (SHORT, LONG)  
2. Int Reject (OFF, 1, 2, 3)  
3. Noise Reject (OFF, ON)  
4. Echo Stretch (OFF, ON)  
5. Radar Mode (CU, WPT-UP)  
3. Nav Data  
1. Navigator (ALL, GPS, LC)  
2. Nav Data Disp (OFF, ON)  
3. Pos Disp Mode (L/L, TD)  
4. Depth Unit (M, FA, FT)  
5. Temp Unit ( C, F)  
6. STBY Display (NORM, NAV)  
4. Mode & Function  
1. Window Display (Zoom, Wide)  
2. Watchman (OFF, 5', 10', 20')  
3. Alarm Mode (IN, OUT)  
4. VRM Unit (NM, KM, SM)  
5. EBL Ref (REL, TRUE)  
6. Range (1/8, 1/4, 1/2, 3/4, 1, 1.5, 2, 3,  
4, 6, 8, 12, 16, 24, 36, 48)  
5. Tuning (AUTO, MANUAL)  
6. Self Check (Checks equiment for proper operation.)  
7. Installation Setup 1 (For installation use.)  
Default settings shown in bold italic.  
A-1  
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SPECIFICATIONS OF MARINE RADAR  
MODEL 851 MARK-2  
1. GENERAL  
(1) Indication System  
PPI Daylight display, raster scan, 4 tones in monochrome  
(2) Range, Pulse Length (PL) & Pulse Repetition Rate (PRR)  
Range (nm)  
Pulse Length (µs)  
PRR (Hz  
approx.)  
2100  
0.125 to 1.5  
1.5 to 3  
0.08  
0.3  
1200  
3 to 48  
0.8  
800  
(3) Range Resolution  
32 m  
(4) Bearing Resolution  
(5) Minimum Range  
2.7º  
27 m  
(6) Bearing Accuracy  
(7) Range Ring Accuracy  
Within ±1º  
1 % of range or 8 m, whichever is the greater  
2. SCANNER UNIT  
(1) Radiator  
Slotted wave-guide array  
Horizontal  
(2) Polarization  
(3) Antenna Rotation Speed  
(4) Radiator Length  
(5) Horizontal Beamwidth  
(6) Vertical Beamwidth  
(7) Sidelobe Attenuation  
(8) Bearing Wind  
24 rpm nominal  
100 cm  
2.4° nominal  
25° nominal  
less than -24 dB, -30 dB outside of main-lobe  
51.5 m/s (100 knots) relative  
3. TRANSCEIVER MODULE  
(1) Frequency and Modulation 9410 MHz ±30MHz (X band), P0N  
(2) Peak Output Power  
(3) Modulator  
4 kW nominal  
FET Switching Method  
60 MHz  
(4) Intermediate Frequency  
(5) Tuning  
Automatic  
(6) Magnetron  
MG5248 or E3571/E3571A  
MIC (Microwave IC)  
10 MHz  
(7) Receiver Front End  
(8) Bandwidth  
(9) Duplexer  
Circulator with diode limiter  
90 seconds approx.  
(10) Time of Heat-up  
SP - 1  
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4. DISPLAY UNIT  
(1) Picture Tube  
(2) Effective Area  
8 inch rectangular monochrome LCD, 122.4 mm x 163.1 mm  
481(H) x 640(V) dots, Effective radar display area: 481 x 481 dots  
(3) Range, Range Interval, Number of Rings  
Range (NM) 0.125 0.25 0.5 0.75 1 1.5 2  
Ring Interval (NM) 0.0625 0.125 0.125 0.25 0.25 0.5 0.5 1  
Number of Rings  
(4) Markers  
3
4
1
4
6
2
3
8 12 16 24 36 48  
2
4
3
4
4
4
6 12 12  
2
2
4
3
4
3
4
3
4
3
4
Heading Line, Bearing Scale, Range Rings,  
Variable Range Marker (VRM), Electronic Bearing Line (EBL),  
Tuning Bar, Alarm Zone,  
Waypoint Mark (navigation input required)  
North Mark (heading sensor input required)  
Range, Range Ring Interval, Display Mode (HU),  
Interference Rejection (IR), Variable Range Marker (VRM),  
Electronic Bearing Line (EBL), Stand-by (ST-BY),  
Guard Alarm (G(IN), G(OUT)), Echo Stretch (ES),  
Range and Bearing to Cursor, *Bearing or L/L Position,  
Echo Tailing (TRAIL), Trailing Time, Trailing Elapsed Time,  
Watchman (WATCHMAN), Zoomed Display (ZOOM)  
*Ship’s speed (SPD), **Water temperature, **Water depth  
*: Navigation data required, **: Echo sounder data required  
IEC 61162-1 adopted  
(5) Alphanumeric Indications  
(6) Input Data  
Own ship’s position:  
Ship’s speed:  
GGA>RMA>RMC>GLL  
RMA>RMC>VTG>VBW  
Bearing (True):  
Bearing (Magnetic):  
Course (True):  
HDT>HDG*1>HDM*1  
HDM>HDG*1>HDT*1  
RMA>RMC>VTG  
Course (Magnetic):  
VTG>RMA  
Waypoint (Range, Bearing): RMB>BWC>BWR  
Loran time difference:  
Water depth  
RMA>GLC>GTD  
DPT>DBK>DBS>DBT  
MTW  
Water Temperature  
*1: calculated by magnetic drift  
(7) Output Data  
Alarm signal  
Radar signal  
12 VDC, 100 mA or less  
For radar remote display  
SP - 2  
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5. POWER SUPPLY  
(1) Rated Voltage/Current  
(2) Rectifier (option)  
12-24 VDC: 5.0-2.5 A  
100/110/115/200/220/230 VAC, 1 phase, 50/60 Hz  
6. ENVIRONMENTAL CONDITION  
(1) Ambient Temperature  
(IEC 60945)  
Scanner Unit: -25°C to +70°C  
Display Unit: -15°C to +55°C  
93 % ±2% at +40°C  
Scanner Unit: IPX6  
Display Unit: IPX5  
IEC 60945  
(2) Relative Humidity  
(3) Waterproofing  
(IEC 60529)  
(4) Bearing Vibration  
7. COATING COLOR  
(1) Display Unit  
Panel: N3.0, Chassis: 2.5GY5/1.5  
N9.5 (upper), 2.5PB3.5/10 (lower)  
(2) Scanner Unit  
8. COMPASS SAFE DISTANCE  
(1) Display Unit  
Standard: 0.70 m  
Standard: 1.00 m  
Steering: 0.50 m  
Steering: 0.75 m  
(2) Scanner Unit  
SP - 3  
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INDEX  
A
F
A.C RAIN.....................................................2-5  
FTC............................................... 2-4-2-6, 3-6  
B
Fuse ............................................................ 4-2  
G
BRILL key............................................ 2-1, 2-3  
Backlight/Brilliance menu ............................2-9  
Backlightings ...............................................2-3  
Bearing measurement.................................2-7  
Bearing resolution........................................3-2  
Blind and shadow sectors ...........................3-4  
Illumination ..................................................2-4  
C
GUARD key........................................2-1, 2-13  
GAIN ....................................................2-4, 3-6  
Guard alarm......................................2-12-2-14  
H
HM OFF key.......................................2-1, 2-21  
Heading marker .................................2-2, 2-20  
Head-up mode .......................................... 2-12  
I
Curse-up mode..........................................2-12  
Control panel ...............................................2-1  
Cursor..........................................................2-2  
Cursor position ..........................................2-21  
Cursor range................................................2-2  
D
Indirect echoes............................................ 3-4  
M
MENU key................................................... 2-1  
Maintenance ............................................... 4-1  
Menu .....................................................2-8-2-9  
Menu tree....................................................A-1  
Mode & Function menu............................... 2-9  
Multiple echoes........................................... 3-3  
N
DISP MODE key........................ 2-1, 2-10-2-11  
Display mode.............................................2-10  
E
EBL...................................................... 2-2, 2-7  
EBL reference............................................2-19  
EBL key ............................................... 2-1, 2-7  
ECHO key............................................ 2-1, 2-4  
ENT key.......................................................2-1  
Echo stretch...............................................2-18  
Echo trail....................................................2-16  
Nav Data menu........................................... 2-9  
Navigation data......................................... 2-17  
Noise rejection .......................................... 2-15  
O
OFF CENTER key .............................2-1, 2-15  
Omnipad...................................................... 2-1  
Index-1  
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P
W
P/L, IR, & Radar menu ................................2-9  
POWER key ................................................2-1  
Post Disp Mode .........................................2-17  
Pulselength................................................2-15  
R
WPT-UP mode.......................................... 2-12  
Watchman................................................. 2-19  
Wide display.............................................. 2-11  
Window Display ........................................ 2-11  
Z
RANGE key ......................................... 2-1, 2-3  
RINGS key........................................... 2-1, 2-6  
Radar horizon..............................................3-1  
Radar wave .................................................3-1  
Range  
Zoom display............................................. 2-11  
Measuring................................................2-6  
Selecting..................................................2-3  
Range resolution .........................................3-2  
S
ST-BY TX key..............................................2-3  
STC .............................................................2-4  
Self test........................................................4-3  
Side-lobe echoes.........................................3-3  
Sub-refraction..............................................3-1  
Super-refraction...........................................3-1  
System configuration......................................v  
T
Tone.............................................................2-3  
TONE key............................................ 2-1, 2-3  
TRAIL key.......................................... 2-1, 2-16  
Troubleshooting...........................................4-2  
Tuning..........................................................2-6  
V
VRM..................................................... 2-2, 2-7  
VRM key.............................................. 2-1, 2-7  
Index-2  
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