Furuno 851 MARK-2 User Manual 2
MARINE RADAR
MODEL 851 MARK-2
(
C
9-52, Ashihara-cho,
Nishinomiya, Japan
Telephone: 0798-65-2111
Telefax: 0798-65-4200
All rights reserved.
Printed in Japan
Your Local Agent/Dealer
FIRST EDITION : JUN. 2000
D : JUL. 9, 2001
PUB. No. OME-34900
YOSH)
MODEL 851 MARK-2
SAFETY INSTRUCTIONS
ELECTRICAL
SHOCK
HAZARD
WARNING
Do not open the equipment.
Hazardous voltage which can
cause electrical shock, burn or
serious injury exists inside the
equipment. Only qualified
personnel should work inside
the equipment.
Wear a safety belt and hard
hat when working on the
antenna unit.
Serious injury or death can
result if someone falls from
the radar antenna mast.
Stay away from transmitting
antenna.
The radar antenna emits microwave radiation which can
be harmful to the human body,
particularly the eyes. Never
look directly into the antenna
radiator from a distance of
less than 1 m when the radar
is in operation.
WARNING
Do not disassemble or modify the
equipment.
Fire, electrical shock or serious injury can
result.
Turn off the power immediately if water
leaks into the equipment or the
equipment is emitting smoke or fire.
Fire or equipment damage can result if a
different cable is used.
Keep heater away from equipment.
Heat can alter equipment shape and melt
the power cord, which can cause fire or
electrical shock.
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 warning sign near the switch
indicating it should not be
turned on while the antenna
unit is being serviced.
Prevent the potential risk of
someone begin struck by the
rotating antenna and exposure to RF radiation hazard.
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.
Name: Warning Label (2)
Type: 03-129-1001-0
Code No.: 100-236-740
i
TABLE OF CONTENTS
FOREWORD.......................................... iv
SYSTEM CONFIGURATION .................. v
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
Bearing.......................................1-1
1.5 Radar Wave Speed and Antenna
Rotation Speed ..........................1-2
1.6 The Radar Display...................... 1-2
2. OPERATION
2.1 Control Description..................... 2-1
2.2 Display Indications and
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
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
Mode........................................ 2-12
2.16 Guard Alarm ...........................2-12
2.17 Suppressing Radar
Interference..............................2-14
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
long range echoes) .................. 2-18
2.24 Selecting Unit of
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
During Stand-by....................... 2-20
2.30 Outputting Cursor Position to
Navigator ................................. 2-21
2.31 Displaying Cursor Position,
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
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
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
ii
MENU TREE....................................... A-1
SPECIFICATIONS............................SP-1
INDEX.......................................... index-1
Declaration of Conformity
iii
FOREWORD
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.
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 properly
installed and maintained. Please carefully
read and follow the recommended procedures
for installation, operation and maintenance.
While this unit can be installed by the
purchaser, any purchaser who has doubts
about his or her technical abilities may wish to
have the unit installed by a FURUNO
representative or other qualified technician.
The importance of a thorough installation
cannot be overemphasized.
Features
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:
• 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.
• 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.
• 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.
Thank you for considering and purchasing
FURUNO equipment.
iv
• 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.)
• Zoom feature provided.
• Omnipad makes the selection of target and
menu items easy.
SYSTEM CONFIGURATION
Antenna unit
Navigation Device
Echo Sounder
Gyrocompass
Integrated Heading
Sensor PG-1000
Gyro Converter
AD-100
Option
Ship's Mains
12-24 VDC
Remote Display
FMD-811
External Alarm
Buzzer OP03-169
Rectifier
RU-3423
Ship's Mains
100/110/115 V A C
200/220/230 V A C
1φ, 50/60 Hz
MODEL 851 MARK-2
v
1. PRINCIPLE OF OPERATION
1.1 What is Radar?
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.
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.
1.3 How Radar Determines Range
Radar determines the distance to the target
by calculating the time difference between
the transmission of a radar signal and the
reception of the reflected echo. It is a
known fact that radar waves travel at a
nearly constant speed of 162,000 nautical
miles per second. Therefore the time
required for a transmitted signal to travel to
the target and return as an echo to the
source is a measure of the distance to the
target. Note that the echo makes a
complete round trip, but only half the time
of travel is needed to determine the oneway 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
1.5 Radar Wave Speed and
1.6 The Radar Display
Antenna Rotation Speed
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.
Targets
A
D
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.
With a continuous display of the images of
targets, the motion of the transmitting ship
is also displayed.
Heading marker
Range and bearing
of a target, relative
to own ship, are
A
D
readable on the PPI.
B
C
Own ship
(radar)
(A) Bird's eye view of situation
B
C
Own ship
in center
(B) Radar picture of (A)
Figure 1-1 How radar works
1-2
2. OPERATION
2.1 Control Description
Omnipad
Shifts cursor, VRM
and EBL; selects
items and options
on menu.
Registers selection
on menus.
Adjusts GAIN,
STC, A.C RAIN
and FTC.
Adjusts display
tone.
Turns the EBL
on/off.
Plots targets' trails.
Sets guard
zone area.
ENT
ECHO
TONE
EBL
TRAIL
GUARD
RANGE
MENU
HM
OFF
BRILL
VRM
RINGS
OFF
CENTER
Opens/closes menus.
Erases heading marker;
selects cursor data (Lat/Long, R/B);
outputs cursor position.
Selects radar range.
Adjusts display brilliance.
Turns the VRM on/off.
Turns the range
rings on/off.
Off centers
the display.
Selects display mode;
erases heading error
indication.
DISP
MODE
ST-BY
TX
POWER
Figure 2-1 Control panel
Sets radar in stand-by;
transmits radar pulse.
Turns power on/off.
2-1
2.2 Display Indications and Markers
Heading (requires
heading data)
Range
Range ring interval
Presentation mode
Off center
Pulsewidth
Heading marker
CU
OFF
CENTER
SP
1.5
0.5
HDG 326.8˚
NM
TRAIL
0:00
15S
AUTO
G ( IN )
FTC1
ES
IR
Echo trail, AUTO tuning
Echo trail elapsed time,
echo trail time, tuning
indicator
Guard zone
FTC
(rain clutter suppressor)
Echo stretch
Guard zone
area
Cursor
EBL
VRM EBL + CURSOR
0.675
NM
VRM
range
232.5˚
EBL
bearing
R
0.681NM 308.7˚
Figure 2-2 Display indications
Cursor
range
R
Cursor
bearing
Interference rejector
Range rings
VRM
Range and bearing to
cursor or cursor position in
latitude and longitude may
}
be displayed by pressing
the [HM OFF] key.
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.
2-2
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.
!
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.
WARNING
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
After the power is turned on and the
magnetron has warmed up, ST-BY (StandBy) appears at the screen center. This
means the radar is now fully operational. In
stand-by the radar is available for use at
anytime—but no radar waves are being
transmitted.
Press the [ST-BY TX] key to transmit.
When transmitting, any echoes reflected
from targets appear on the display. This
radar displays echoes in four tones of gray
according to echo strength.
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.
2.6 Adjusting LCD Backlighting and Display Tone
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.
Procedure
1. Press the [BRILL] key (or [TONE] key).
The display shown in Figure 2-3
appears.
BRILL
UP
TONE
DOWN
TONE
UP
Item selected
for adjustment
2.5 Selecting the Range
The range selected automatically
determines the range ring interval, the
number of range rings, pulselength and
pulse repetition rate, for optimal detection
capability in short to long ranges.
Procedure
Press the [– RANGE +] key. The range and
range ring interval appear at the top left
corner on the display.
BRILL
Tone
setting
19 7
DOWN
<MENU> TO EXIT
LCD brilliance
setting
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.
2-3
2.7 Adjusting Control Panel Illumination
Procedure
2. Press the omnipad at 6 o’clock/12
o’clock to select item to adjust. Current
selection is circumscribed by dashed
rectangle.
1. Press the [MENU] key.
2. Press the omnipad at 6 o’clock to
select Backlight/Brilliance and press
the [ENT] key.
3. Press the omnipad at 6 o’clock to
select Panel.
4. Press the omnipad at 3 o’clock/9
o’clock to select illumination level; 4 is
the highest.
5. Press the [ENT] key followed by the
[MENU] key.
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.
AUTO
[
GAIN
STC
A.C RAIN
ECHO KEY
TO EXIT
◆
◆
FTC
01
[
MAN
AUTO 1 2 3
MAN
01
00
0 1 2
Item selected
for adjustment
Select auto or
manual by
pressing the
omnipad at
6 o'clock or
12 o'clock and
pressing [ENT]
key .
3. 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.
How to adjust the GAIN (sensitivity)
The GAIN works in precisely the same
manner as the volume control of a
broadcast receiver, amplifying the signals
received.
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.
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.
Select item/option
by pressing appropriate
omnipad arrow.
Figure 2-4 Display for adjustment of GAIN,
STC, A.C RAIN and FTC
Current level
2-4
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).
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.
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
disappeared to leeward, but a little is still
visible windward.
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 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.
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.
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
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.
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.
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.
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
The receiver can be tuned automatically or
manually. For automatic tuning the receiver
is tuned each time you switch from standby 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.)
1.5
0.5
Note:
NM
Figure 2-7 Tuning indicator
When you switch from manual to
automatic, wait 4 seconds before
closing the MENU. Otherwise
automatic tuning may not work
properly.
indicator
Tuning
AUTO
2.10 Measuring the Range
You can measure the range to a target
three ways: by the range rings, by the
cursor, and by the VRM (Variable Range
Marker).
By range 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.
By cursor
Operate the omnipad to place the cursor
intersection on the inside edge of the target
echo. The range to the target, as well as
the bearing, appears at the bottom of the
display.
2-6
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