FURUNO MARK-3 1761 marine radar OPERATOR'S MANUAL
Below you will find brief information for marine radar MARK-3 1761. The MARK-3 1761 marine radar is a compact, lightweight, and low-cost radar that is designed to meet the rigorous demands of the marine environment. It features a durable brushless antenna motor, on-screen alphanumeric readout of all operational information, and a variety of standard features, including EBL, VRM, Guard Alarm, Display Off Center, and Echo Trail. The MARK-3 1761 also includes a Watchman feature that periodically transmits the radar to check for radar targets that may be entering the alarm zone. Additionally the MARK-3 1761 can display ship's position in latitude and longitude, range and bearing to a waypoint, and ship's speed/heading/course.
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9 - 5 2 , A s h i h a r a - c h o ,
N i s h i n o m i y a , J a p a n
T e l e p h o n e : 0 7 9 8 - 6 5 - 2 1 1 1
T e l e f a x : 0 7 9 8 - 6 5 - 4 2 0 0
A l l r i g h t s r e s e r v e d .
Printed in Japan
( Y O S H )
P U B . N o . O M E - 3 4 8 1 0
M O D E L 1 7 6 1 M A R K - 3
Y o u r L o c a l A g e n t / D e a l e r
F I R S T E D I T I O N : A U G . 1 9 9 8
SAFETY INSTRUCTIONS
DANGER
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.
Radio Frequency Radiation Hazard
The radar antenna emits electromagnetic radio frequency (RF) energy which can be harmful, particularly to your eyes. Never look directly into the antenna aperture from a close distance while the radar is in operation or expose yourself to the transmitting antenna at a close distance.
Distances at which RF radiation levels of 100 and 10 W/m 2 exist are given in the table below.
Note: If the antenna unit is installed at a close distance in front of the wheel house, your administration may require halt of transmission within a certain sector of antenna revolution. This is possible—Ask your FURUNO representative or dealer to provide this feature.
M O D E L
1 7 6 1 M K 3
R a d i a t o r t y p e
X N 1 0 A
D i s t a
1 0 0 n c e t o
W / m 2 p o i n t
0 .
2 m
D i s t a n c e
1 0 W / m 2 t o p o i n t
W o r s t c a s e 3 .
0 m
i
DANGER
Before turning on the radar make sure no one is near the scanner unit.
Prevent the potential risk of someone begin struck by the rotating antenna and exposure to RF radiation hazard.
WARNING
Use the proper fuse.
Fuse rating is shown in the chapter 5.
Use of a wrong fuse can result in equipment damage
Do not operate the equipment with wet hands.
Electrical shock can result.
WARNING
Do not open the equipment.
Improper handling can result in electrical shock. Only qualified personnel shold work inside the equipment.
Do not disassemble or modify the equipment.
Fire electrical shock or serious injury can result.
Turn off the power immediately if water leaks into the equipment or the equipment is emitting smoke or fire.
Continued use of the equipment can cause fire or electrical shock.
Do not place liquid-filled containers on the top of the equipment.
Fire or electrical shock can result if a liquid spills into the equipment.
CAUTION
Do not use the equipment for other than its intended purpose.
Use of the equipment as a stepping stool, for example, can result in personal injury or equipment damage.
No one navigation device should ever be solely replied upon for the navigation of a vessel.
Always confirm position against all available aids to navigation, for safety of vessel and crew.
Two warning labels are attached to the display unit and scanner unit. Do not remove these labels.
If labels are peeling off or are illegible, contact a FURUNO agent or dealer.
<Display Unit>
Name: Warning Label (1)
Type: 86-003-1011-0
Code no.: 100-236-230
WARNING
To avoid electrical shock, do not remove cover. No user-serviceable parts inside.
<Scanner Unit>
Name: Radiation Warning
Label
Type: 03-142-3201-0
Code no.: 100-266-890
WARNING
Radiation hazard. Only qualified personnel should work inside scanner.
Confirm that TX has stopped before opening scanner.
ii
FOREWORD
Congratulations on your choice of the
FURUNO MODEL 1761 MARK-3 Marine Radar. 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 through installation can not be overemphasized.
We would appreciate hearing from you, the end-user, about whether we are achieving our purposes.
Thank you for considering and purchasing
FURUNO equipment.
Features
Your radar has a large variety of functions, all contained in a remarkably small cabinet.
The main features of the MODEL 1761
MARK-3 are:
¡
Traditional FURUNO reliability and quality in a compact, lightweight and low-cost radar.
¡
Durable brushless antenna motor.
¡
On-screen alphanumeric readout of all operational information.
¡
Standard features include EBL (Electronic
Bearing Line), VRM (Variable Range
Marker), Guard Alarm, Display Off Center, and Echo Trail.
¡
Watchman feature periodically transmits the radar to check for radar targets which may be entering the alarm zone.
¡
Ship’s position in latitude and longitude, range and bearing to a waypoint, and ship’s speed/heading/course can be shown in the bottom text area. (Requires a navigation aid which can output such data in IEC 61162 format.)
¡
Zoom feature provided.
iii
TABLE OF CONTENTS
FOREWORD .............................. iii
MENU TREE ............................... v
TABLE OF CONTENTS BY
INDICATION, MARKER ............. vi
SYSTEM CONFIGURATION..... vii
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 .............................. 1-1
1.6 The Radar Display ......................... 1-1
2. OPERATION
2.1 Control Description ......................... 2-1
2.2 Turning the Radar On/Off ............... 2-2
2.3 Transmitting .................................... 2-2
2.4 Stand-by ......................................... 2-2
2.5 Selecting the Range ....................... 2-2
2.6 Adjusting Picture Brilliance ............. 2-2
2.7 Adjusting Receiver Sensitivity ........ 2-2
2.8 Adjusting the A/C SEA Control
(reducing sea clutter) ..................... 2-3
2.9 Adjusting the A/C RAIN Control
(reducing rain clutter) ..................... 2-4
2.10 Adjusting FTC ............................... 2-4
2.11 Turning the Radar Receiver ......... 2-4
2.12 Erasing the Heading Marker ........ 2-4
2.13 Select the Cursor Data Display .... 2-5
2.14 Turning the Range Ring On/Off ... 2-5
2.15 Measuring the Range ................... 2-5
2.16 Measuring the Bearing ................. 2-5
2.17 Shifting and Zooming the Display ......
..................................................... 2-6
2.18 Menu Operation ........................... 2-7
2.19 Echo Stretch ................................. 2-8
2.20 Suppressing Radar Interference .. 2-8
2.21 Adjusting Control Panel Brilliance ......
..................................................... 2-8
2.22 Selecting Ranges ......................... 2-9
2.23 EBL/Cursor Bearing Reference ... 2-9
2.24 Guard Alarm ................................. 2-9
2.25 Watchman .................................. 2-10
2.26 Plotting ........................................ 2-11
2.27 Navigation Data Display .............. 2-11
3. FALSE ECHOES
3.1 Multiple Echoes .............................. 3-1
3.2 Side-lobe Echoes ........................... 3-1
3.3 Indirect Echoes .............................. 3-2
3.4 Blind and Shadow Sectors ............. 3-2
3.5 SART (Search and Rescue
Transponder) ................................. 3-3
4. MAINTENANCE & TROUBLE-
SHOOTING
4.1 Preventive Maintenance ................ 4-1
4.2 Replacing the Fuse ........................ 4-1
4.3 Troubleshooting .............................. 4-2
4.4 Life Expectancy of Magnetron ....... 4-3
SPECIFICATIONS ................ SP-1
INDEX .....................................IN-1
iv
MENU TREE
MENU KEY
1. ECHO STRETCH (ON, OFF)
2. I. REJECT (OFF, ON)
3. PANEL DIMMER (0, 1, 2, 3, 4)
4. PLOT INTVL (CONT, 30S, 1M, 3M, 6M)
5. PLOT BRILL (LOW,
@
HIGH)
6. RANGE (NM) set with (RING)
(1/4, 1/2, 3/4, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 48)
7. WATCHMAN (OFF, 5M, 10M, 20M)
8. NAV DATA (ON, OFF)
9. EBL/+CURSOR (TRUE, REL)
v
TABLE OF CONTENTS BY
INDICATION, MARKER
Plotting (P.2-11)
MAG (or GYRO) BEARING (option)
Heading marker (P.2-4)
Range (P.2-2)
Range ring interval (P.2-2)
Shift (or Zoom) (P.2-6)
Watchman (P.2-10)
12 NM
3.0 NM
SHIFT
Elapsed time (P.2-11)
Plotting interval (P.2-11)
Tuning indicator (P.2-11)
Echo stretch (P.2-8)
Guard alarm (P.3-4)
MAG 115.0¡
WATCHMAN
PLOT 3M
18:25 ES
*
GUARD
FTC
IR
FTC (P.2-4)
Interference rejector (P.2-8)
EBL (P.2-6)
Guard zone (P.2-9)
Cursor (P.2-5, 6)
Range ring (P.2-3, 2-5)
EBL1 bearing (P.2-6)
EBL
9.05 NM
Cursor data(P.2-5)
Bearing /Range or
Latitude/Longitude
VRM
2.62 NM
VRM range (P.2-5)
vi
SYSTEM CONFIGURATION
Scanner Unit
XN10A-RSB-0070-065
Navigation device
IEC 61162* (In/Out)
Gyrocompass
Gyro Converter
AD-100
Intergrated Heading
Sensor PG-1000
Display Unit
RDP-099
12 VDC: 10A
24/32 VDC: 5A
*Equivalent to NMEA 0183
Option
12/24/32 VDC
External Alarm
Buzzer OP03-21
Rectifier
RU-3423
115/230 VAC
vii
1. PRINCIPLE OF OPERATION
1.1 What is Radar?
The term “RADAR” is an acronym meaning
RAdio Detection And Ranging. Although the basic principles of radar were developed during World War II, echoes as an aid to navigation is not a new development.
1.2 How Ships Determined
Position Before Radar
Before the invention of radar, when running in fog near a rugged shoreline, ships would sound a short blast on their whistles, fire a shot, or strike a bell. The time between the origination of the sound and the returning of the echo indicated how far the ship was from the cliffs or the shore. The direction from which the echo was heard indicated the relative bearing of the shore.
1.4 How Radar Determines
Bearing
The bearing to a target found by the radar is determined by the direction in which the radar scanner antenna is pointing when it emits an electronic pulse and then receives a returning echo. Each time the scanner 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.
1.5 Radar Wave Speed and
Scanner Rotation Speed
Note that the speed of the radar waves out to the target and back again as echoes is extremely fast compared to the speed of rotation of the scanner. By the time radar echoes have returned to the scanner, the amount of scanner rotation after initial transmission of the radar pulse is extremely small.
1.3 How Radar Determines
Range
Radar determines the distance to the target by calculating the time difference between the transmission of a radar signal and the reception of the reflected echo. It is a known fact that radar waves travel at a nearly constant speed of 162,000 nautical miles per second.
Therefore the time required for a transmitted signal to travel to the target and return as an echo to the source is a measure of the distance to the target. Note that the echo makes a complete round trip, but only half the time of travel is needed to determine the one-way distance to the target. This radar automatically takes this into account in making the range calculation.
1.6 The Radar Display
The range and bearing of a target is displayed on what is called a Plan Position Indicator
(PPI). This display is essentially a polar diagram, with the transmitting ship’s position at the center. Images of target echoes are received and displayed at their relative bearings, and at their distance from the PPI center.
With a continuous display of the images of targets, the motion of the transmitting ship is also displayed.
1-1
1-2
A
D
Targets
A
Heading marker
D
Range and bearing of a target, relative to own ship, are readable on the PPI.
B
C
B
C
Own ship
(radar)
(A) Bird's eye view of situation
Own ship in center
(B) Radar picture of (A)
Figure 1-1 How radar works
2. OPERATION
2.1 Control Description
Turns power on.
Press together with [STBY/TX] key to turn power off.
Alternates between stand-by and transmit.
Lights (in green) to show the radar is in the "echonomy
(stand-by)" mode.
Adjusts the brightness of the screen.
Selects radar range.
The "+" and "-" touchpads select a higher and lower range, respectively.
Selets items during the menu display.
Shifts the display; turns the zoom function on, and restores normal picture, in that order.
Turns the Electronic Bearing
Line (EBL) on and off.
Turns on and off the guard zone alarm.
GAIN
POWER
OFF
STBY
T X
ECONOMY
PUSH/HM OFF
A/C SEA
PUSH/PLOT
A/C RAIN
BRILL
PUSH/FTC
RANGE
SHIFT
ZOOM
EBL
RING
VRM
GUARD MENU
(Control) Adjusts sensitivity of radar
receiver.
(Switch) 1. Temporarily erases heading
marker.
2. Change + cursor data from
R/B to L/L and vice versa.
(Control) Reduces sea clutter caused
by waves.
(Switch) Turns on/off the radar
target plotting
(Control) Reduces rain clutters.
(Switch) Suppresses heavy
precipitation.
Turns the fixed range rings on and off.
Turns the Variable Range Marker
(VRM) on and off.
Turns the menu display on and off.
Figure 2-1 Control panel
Trackball
(1) Shifts cursor, EBL and VRM.
(2) Sets guard zone.
(3) Selects items and options on menu.
(4) Shifts origin of EBL and VRM.
2-1
2.2 Turning the Radar On/Off
After confirming there are no crew near the scanner unit, press the [POWER] key to turn on the power.
The front panel will light up. The magnetron takes about two minutes and thirty seconds to warm up before the radar can be operated. The time remaining for warm up of the magnetron appears at the center of the display, counting down from 2:29 to 0:01.
To turn off the radar, press the [POWER] and
[TX] key together.
2.3 Transmitting
After the power is turned on and the magnetron has warmed up, the message “ST-BY”
(Stand-By) appears at the center of the display, showing the radar is ready to transmit.
However, no targets will appear on the screen until the radar is transmitting by pressing the
[TX] key (TX is short for “transmit). In standby the radar is available for use at anytime but no radar waves are being transmit.
2.5
Selecting the Range
The range selected automatically determines the fixed range ring interval, the number of fixed range rings, pulselength, and pulse repetition rate, for optimal detection in short to long ranges. The range and ring interval appear at the top left corner of the display.
Selecting the range
Press the [- RANGE +] key. The range and range ring interval appear at the top left corner on the display.
Tips for selecting the range
• When navigating in or around crowded harbors, select a short range to watch for possible collision situation.
• 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
Stand-by
When you won’t be using the radar for an extended period, but you want to keep it in a state of readiness, place it in stand-by by pressing the [TX] key. The display shows
“STBY,” (default setting) or goes into the economy mode. (You can select stand-by condition on the menu. )
2.6
Adjusting Picture
Brilliance
The [BRILL] key adjusts the brilliance of the radar picture in eight levels.
Press the [BRILL] key to set the brilliance level.
Economy mode
The CRT can be set to automatically turn itself off when in stand-by, to reduce power consumption. This feature is called the
“economy mode”. When the economy mode is on, the “ECONOMY” indication under the
[TX] key lights.
2.7
Adjusting Receiver
Sensitivity
The [GAIN] control adjusts the sensitivity of the receiver. It works in precisely the same manner as the volume control of a broadcast receiver, amplifying the signals received.
The proper setting is such that the background noise is just visible on the screen. If you set up noise is just visible on the screen.
If you set up for too little sensitivity, weak echoes may be missed. On the other hand excessive sensitivity yields too much background noise; strong targets may be missed because of the poor contrast between desired
2-2
echoes and the background noise on the display.
To adjust receiver sensitivity, transmit on long range, and adjust the [GAIN] control so background noise is just visible on the screen.
Tips on adjusting GAIN
• In certain circumstances it may be useful to reduce the gain slightly to improve range resolution, clear up the picture, or reduce clutter caused by rain or snow.
• 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 radially. With reduction in the gain setting, the echoes may be made to appear as separate pips on the display.
• When sailing or cruising in crowded regions a slight reduction in gain often helps to clear up the picture. This should be done carefully, otherwise weak targets may be missed.
• Echoes from ships inside a squall or storm may be obscured if the gain is at its normal setting, since the clutter may have masked, but not completely, echoes from the targets.
Note: In all cases, return the gain to its original position after any temporary reduction is no longer required.
How the A/C SEA control works
The [A/C SEA] control reduces the amplification of echoes at short ranges (where clutter is the greatest) and progressively increases amplification as the range increases, so amplification will be normal at those ranges where there is no sea clutter.
Adjusting the A/C SEA control
The proper setting of the A/C SEA should be such that the clutter is broken up into small dots, and small targets become distinguishable.
If the control is set too low, targets will be hidden in the clutter, while if it is set too high, both sea clutter and targets will disappear from the display. In most cases adjust the control until clutter has disappeared to leeward, but a little is still visible windward.
1. Confirm that the sensitivity is properly adjusted, and then transmit on short range.
2. Adjust the [A/C SEA] control so small targets are distinguishable but some clutter remains on the display.
2.8
Adjusting the A/C SEA
Control
(reducing sea clutter)
Echoes from waves can be troublesome, covering the central part of the display with random signals known as “sea clutter”. The higher the waves, and the higher the 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 2-2.) When sea clutter masks the picture, adjust the A/C SEA control to reduce the clutter.
Sea clutter at display center
A/C SEA control adjusted; sea clutter suppressed.
Figure 2-2 How to adjust the A/C SEA control
Tip for adjusting the A/C SEA
A common mistake is to over-adjust the circuit so all the removed. As an example set up for maximum A/C SEA. You will see how the center of the display becomes dark. This dark zone can be dangerous (targets may be missed), especially if the sensitivity is not properly adjusted. Always leave a little clutter visible on the display to be sure weak echoes will not be suppressed. If there is no clutter visible on the display, turn off the circuit.
2-3
2.9 Adjusting the A/C RAIN
Control
(reducing rain clutter)
The vertical beamwidth of the antenna is designed to see surface targets even when the ship is rolling. However, by this design the unit will also detect rain clutter (rain, snow, hail, etc.) in the same manner as normal targets. Figure 2-3 shows the appearance of rain clutter on the display.
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.
Adjusting A/C RAIN
When rain clutter masks echoes, adjust the
[A/C RAIN] control. This control splits up these unwanted echoes into a speckled pattern, marking recognition of solid targets easier.
2.11 Tuning the Radar Receiver
The radar receiver is tuned automatically each time you turn on the power, thus there is no front panel control for adjustment of the receiver. To show the automatic tuning circuit is working, a tuning bar displays tuning condition.
2.12 Erasing the Heading
Marker
The heading marker may occasionally mask a target. To view the target, you can temporarily erase the heading marker by pressing and holding down the [GAIN (HM OFF)] control. Release the control to re-display the markers.
Appearance of rain clutter
A/C RAIN control adjusted; rain clutter suppressed.
Figure 2-3 Effect of A/C RAIN
Note: In addition to reducing clutter, the [A/C
RAIN] control can be used in fine weather to clarify the picture when navigating in confined waters. However, with the circuit activated the receiver is less sensitive. Therefore, turn off the circuit when its function is not required.
Heading marker
Figure 2-4 Heading marker
2.10 Adjusting FTC
To suppress rain clutter from heavy storms or scattered rain clutter, press the [A/C RAIN] control ([FTC] switch). The FTC circuit splits up these unwanted echoes into a speckled pattern, marking recognition of solid targets easier. “FTC” appears at the top right-hand corner of the display when the circuit is turned on.
2-4
2.13 Select the Cursor Data
Display
When connecting with NAV (IEC61162 format) and gyro converter (IEC61162 or AD-
10 format), this radar can show the cursor position by Latitude/longitude at bottom of screen.
Each time pressing [HM OFF] key, the data will change from Range/Bearing to Latitude/ longitude and vice versa.
When the cursor position is displayed by Latitude/Longitude, pressing the [HM OFF] key outputs L/L data of the cursor position (TLL) to the plotter. Then Range/Bearing are displayed instead of L/L.
Measuring by VRM
1. Press the [VRM] key to display a VRM.
(The VRM is the dotted ring.)
2. Place the VRM on the inside edge of the target by operating the trackball.
3. Press the [VRM] key again to fix the VRM to the position.
4. Check the range readout to find the range to the target. To erase the VRM, press and hold down the [VRM] key for about three seconds.
Range
Range ring interval
Target
Cursor
6.0 NM
2.0
VRM
2.14 Turning the Range Ring
On/Off
When range rings obscures a target, you can erase them by pressing the [RING] key.
2.15 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).
Measuring range by range rings
Count the number of rings between the center of the display and the target. Check the range ring interval and judge the distance of the echo from the inner edge of the nearest ring.
To turn the rings on or off, press the [RING] key.
315.1°R
4.0 NM
VRM
4.0 NM
VRM range
Cursor range
Figure 2-5 Measuring Range by the Cursor and the VRM
Unit of range measurement
You can display the range readouts of the
VRM and the cursor in nautical miles or kilometers. This is done at installation.
2.16 Measuring the Bearing
There are two ways to measure the bearing to a target: by the cursor, and by the EBL
(Electronic Bearing Range).
Measuring range by cursor
Operator the trackball 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.
Measuring bearing by cursor
Operate the trackball to bisect the target with the cursor intersection. The bearing to the target appears at the bottom of the display.
Measuring by EBL
1. Press the [EBL] key to display an EBL.
(The EBL is the dotted line.)
2-5
2. Position the EBL so it bisects the target by operating the trackball.
3. Press the [EBL] key again to fix the EBL to the position.
4. Check the bearing readout to find the bearing of the target. To erase the EBL, press and hold down the [EBL] key for about three seconds.
MAG (or GYRO) BEARING*
6.0 NM
2.0
MAG115.0°
Target
Cursor
EBL
• Bearings of stationary or slower moving targets are more accurate than bearings of faster moving targets.
• To minimize bearing errors keep echoes in the outer half of the picture by changing the range scale; angular difference becomes difficult to resolve as a target approaches the center of the display.
2.17 Shifting and Zooming the
Display
The [SHIFT/ZOOM] key has two functions: display shifting and display zoom. Each time the key is pressed the function changes in the following sequence.
Normal
Shift Zoom
EBL
40.0° R 41.5°R
4.0 NM
EBL1 bearing
R: Relative Bearing
T: True Bearing*
Cursor Bearing
R: Relative Bearing
T: True Bearing*
*: Heading sensor
(or gyrocompass)
connection required
Figure 2-6 Measuring Bearing by the EBL and Cursor
The bearing measured by the cursor or the
EBL can be displayed in relative or true bearings (heading sensor or gyrocompass connection required). Relative bearings are relative to the bow of the vessel, and true bearings are relative to the True North. The indication “MAG” (or GYRO”) and the heading sensor (or gyrocompass) bearing (your ship’s bearing) appear at the top of the screen.
Note that the bearing to the cursor always varies with trackball operation. The EBL and its indication, however, are automatically fixed when the [EBL] key is pressed or 10 seconds elapses without trackball operation.
Tips on measuring bearing
• Bearing measurements of smaller targets pips are more accurate; the center of larger target pips is not as easily identified.
Figure 2-7 SHIFT/ZOOM key sequence
Zoom
The zoom feature allows you to double the area between own ship and an arbitrary location, to take a closer look at an area of interest without changing the range.
1. Operate the trackball to place the cursor on the target you want or area you want to zoom.
2-6
Shift
The own ship’s position can be shifted to any position within the current range. The primary advantage of the shifted display is that for any range setting, the view ahead of your own ship can be extended without changing the range.
Place the cursor on area you wish to shift to the screen center and then press the [SHIFT/
ZOOM] key. The indication “SHIFT” appears.
To restore normal operation press the key twice.
Note: If the cursor is not within the current range when the key is pressed, an audible beep sounds and the outermost range ring blinks twice , even if the range rings are off.
2. Press the [SHIFT/ZOOM] key. The indication “ZOOM” appears and brinks.
3. To turn off the zoom, press the [SHIFT/
ZOOM] key again, or change the range.
(Normal display)
Place cursor where desired.
2.18 Menu Operation
The menu, consisting of 9 items, 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 menus by using the trackball, then select item with the [RANGE] key.
Note: Current selections shown in reverse video.
Cursor
Press the
[SHIFT/ZOOM] key.
SHIFT
Press the
[SHIFT/ZOOM]
key.
Press the
[SHIFT/ZOOM] key.
ZOOM
Display shifts.
Display magnifies.
Figure 2-8 Shifting and zooming the display
MENU
SEL MENU BY TRKBALL:
ITEMS WITH RANGE KEY
¡
ECHO STRETCH
2 I. REJECT
3 PANEL DIMMER
4 PLOT INTVL
5 PLOT BRILL
6 RANGE (NM)
SET WITH
(RING)
7 WATCHMAN
8 NAV DATA
9 EBL/+CURSOR
ON
OFF
ON OFF
0 1 2 3 4
CONT 30S 1M 3M 6M
LOW HIGH
1/4 1/2 3/4 1 1.5 2 3
4 6 8 12 16 24 36 48
OFF 5M 10M 20M
ON
OFF
TRUE
REL
Figure 2-9 MENU Display
Table 2-1 Menu Description
4
5
2
3
N o .
1
M e n u
E C H O S T R E T C H
6
7
I N T E R F E R E N C E
R E J E C T I O N
P A N E L D I M M E R
P
P
R
L
L
O
O
A N
T
T
G E
W A T C
I N
B
T
R I
E
L
R
L I
H M A N
V A
A N
L
C E
F u n c t i o n
A c t i v a e c h o e t e s s a l e n n g t d h r e l e a s e s w i s e f o r t h e e b e t t e r c d h o i s t s t a n r e t c c e .
h f u n c t i o n , w h i c h s t r e t c h e s
R e d u c e s o r e il m i n a t e s r a d a r i n t e r f e r e n c e .
A d j u s t s t h e b a c k il g h t i n g o f t h e f r o n t p a n e l i n f i v e s t e p s .
C h a n g e s a n d c o n t i t h e n u o u p l o s .
t t i n g i n t e r v a l i n f i v e s t e p s ; 3 0 s e c .
, 1 m i n .
, 3 m i n .
, 6 m i n .
A d j u s t s t h e b r i g h t n e s s o f t h e p l o t t e d e c h o e s .
P r e s e t s t h e v i d e o .
r a n g e s y o u w a n t t o u s e .
T h e p r e s e t r a n g e s a r e i n r e v e r s e
1 .
2 .
W i t h
M i n i t h e m u m
[ R A N G E ] n u m b e r o k e y , f p l a c e w a n t
P r e s s r a n g e t o s s t h e i s e
[ l e c t a
R ll
I N r a o r
G ] n g d e k e e s .
s y e l t e c t .
o s e l e c t r a n g e i s t t h e w o o r
.
u n d e r il n e d e s e l e c t .
u n d e r t h e r a n g e y o u
M a x i m u m n u m b e r o f
T u r n s o n a n d s e l e c t s t h e w a t c h m a n i n t e r v a l .
1 .
2 .
S
P e r e l
" E C e s c s
O t t
N i n t e r v a l h e
O
[
M
M
Y "
E
(
N i n
5
U m
] i d i c a n k e t i
.
, y o
1 0 n t o il m a c t g i h n t
.
i v s o r a t
2 0 m i n .
) e a f t e r t h e t h e w i w a t c h r a d a t h r m t h a n e t r a n
[ R A N m s o m i d t e s
.
G E f o r
]
T h e a k e y .
b o u t s e c o n d s .
3 0
F a c t o r y s e t t i n g
O F F
O F F
O N
3
C O N T
L O W
1 / 4
1 / 2
4
8
1
2
1 6
4 8
8 N A V D A T A
9 E B L / + C U R S O R B E A R I N G
T u r n s t h e n a v i g a t i o n d a t a d i s p l a y ( n a v i g a t i o n i n p u t r e q u i r e d ) o n a n d o f f .
S e l e c t c o m p a s s t h s e o r b g e a r y r o i n g c o m e a m p a s s u s r e d b y t h e c o n n e c t i o n
E B L r e q u o r i r e c u r s o r d ) o r r e i n l a t r u t i v e e ( m a g n e b e a r i n g .
t i c
" T R
" R E
U E
L " :
" r
: e r e l a t l a t i v i e v e t o t o t t h e h e b
T r o w u e o f
N o r t h t h e v e s s e l
O F F
R E L
2-7
2.19 Echo Stretch
Normally, the reflected echoes from long distance targets appear on the screen as weaker and smaller blips even through they are compensated by the radar’s internal circuitry. The
Echo Stretch function magnifies these small blips.
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “1. ECHO
STRETCH”.
3. Press the [RANGE] key to select “ON”.
The indication “ES” appears at the upper right-hand side of the screen and the echoes are doubled lengthwise.
To turn off the echo stretch, select “OFF” on the MENU display.
Note 1: This function magnifies not only targets but also sea clutter and radar interference are properly adjusted before activating the echo stretch.
Note 2: This function is inactivate on short ranges, that is 0.25 to 1 nautical miles. “ES” appears in reverse video when the echo stretch is turned on in those ranges.
2.20 Suppressing Radar
Interference
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 (or the edge) to the edge (or the center) of the display. Figure 2-11 illustrates interference in the form of curved spokes, Interference effects are distinguishable from normal echoes because they do not appear in the same place on successive rotations of the scanner.
Figure 2-10 Radar interference
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “2. I. RE-
JECT”.
3. Press the [RANGE] key to select “ON”.
(Factory setting is ON.)
The indication “IR” appears at the upper righthand side of the screen. Press the [MENU] key again to erase the menu display.
2.21 Adjusting Control Panel
Brilliance
Adjusts the backlighting of the front panel in five steps.
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “3. PANEL
DIMMER”.
3. Press the [RANGE] key to select level desired.
4. Press the [MENU] key again to erase the menu.
2-8
2.22 Selecting Ranges
This radar has 14 ranges, some which you may not require. You can select or deselect ranges as follows.
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “6.
RANGE”.
3. Press the [RANGE] key to place the underline under the range you want to select or deselect.
4. Press the [RING] key to select or deselect.
5. Repeat step 4 and 5.
Maximum number of ranges is all ranges.
Minimum number of ranges is two.
2.23 EBL/Cursor Bearing
Reference
EBL and cursor bearing can be displayed relative to own ship’s heading (Relative) or with reference to North (True).
Note: Magnetic compass or gyrocompass connection required for true bearing.
1. Press the [MENU] key to open the menu.
2. Operate the trackball to select “9. EBL/
+CURSOR”
3. Press the [RANGE] key to select “TRUE” or “REL (Relative)”.
2.24 Guard Alarm
The alarm allows the operator to set the desired range (0 to maximum range) and bearing (0 to 360 degrees) for a guard zone, called
Auto In/Out alarm. When ships, islands, landmasses, etc. go into (or go out of) the guard zone an audible alarm sounds to call the operator’s attention.
Before setting the alarm, be sure the [GAIN] control is properly adjusted, because the audible alarm sounds when the fifth or more level quantization echoes go into or go out of the guard zone.
1. Mentally create the guard zone you want to display on-screen. See Figure 2-12.
2. Set upper (lower) left edge of the guard zone with the cursor, and press the
[GUARD] key.
The indication “*GUARD” (asterisk blinking) appears at the upper right-hand side of the screen. See Figure 2-12 (2). The asterisk indicates the guard zone is partially set, but the alarm function has not been actuated. It disappears once the guard zone is set completely.
3. Moving the trackball clockwise, set the lower (upper) right edge of the guard zone. The guard zone now appears on the display and alarm function has been actuated, See Figure 2-12 (3).
Note: To create a 360 degree guard zone, rotate the cursor counterclockwise instead of clockwise.
4. Press the [GUARD] key again. The asterisk disappears and the alarm function is actuated after three to five antenna scannings, and then, the indication
“GUARD” is replaced by “G(IN)” or
“G(OUT)”.
5. Any ships, landmasses, etc. coming into or going out of the guard zone will trigger the audible alarm. If the audible alarm sounds you can silence it by pressing the
[GUARD] key. When this is done the indication “GUARD” appears in reverse video.
6. Press the [GUARD] key again to restore the audible alarm. “GUARD” lights in normal video.
7. To cancel both the guard zone and the audible alarm, press and hold down the
[GUARD] key for three seconds.
Note 1: When the range is less than the half of the guard zone range, the guard zone disappears from the screen and “UP RANGE” indication appears. If this happens, select a range which will again display the guard zone on the screen.
2-9
Note 2: 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 A/C SEA, A/C RAIN, FTC and
GAIN to be sure target echoes within the guard zone are not overlooked by the alarm system.
Note: The audible alarm does not sound for the target originally existing the zone.
Case 2: When no targets exist inside the zone, the alarm zone is automatically set to
“Auto In Alarm” mode and the indication
“GUARD” is replaced by “G (IN)”. The audible alarm sounds only on targets which go into the zone. See Figure 2-13 (2).
A
B
Asterisk blinking
Guard zone to set
D
C
A
* G (IN)
Dashed line: no alarm
Drag cursor here.
Guard zone
IN ALARM OUT ALARM
Figure 2-12 Auto In/Out Alarm
(1) Mentally create the guard zone to set.
(2) Drag cursor to top left corner of zone and press
[GUARD].
2.25
Watchman
G (IN)
Guard zone
G (IN)
Drag cursor here.
(4) Guard zone completed.
(3) Drag cursor to bottom right corner of zone and press
[GUARD].
Figure 2-11 Setting Guard Zone
C
The watchman function turns on the radar and transmits its for about 30 seconds at a predetermined interval to check for targets in a guard zone. This feature is useful when you do not need the radar’s function continuously but want to be alerted to radar targets in an area.
When the watchman feature is on, an internal timer turns on the radar every 5, 10 or 20 minutes and the radar transmits for 30 seconds to check for the existence of radar targets in a guard zone.
Auto In/Out Alarm
When the guard zone is set completely, the radar starts searching for targets inside the guard zone for 8 to 12 seconds. The indication “GUARD” appears during this period.
Case 1: When there are targets inside the zone, the alarm zone is automatically set to
“Auto Out Alarm” mode and the indication
“GUARD” is replaced by “G (OUT)”. The audible alarm sounds only on targets which go out of the zone or disappear. See Figure 2-
13 (1).
Tx
St-by
Tx
St-by
1 min
5, 10 or
20 min
1 min 5, 10 or
20 min
Watchman starts.
Figure 2-13How watchman works
2-10
1. Determine the guard zone (usually 360 degrees) with the guard alarm function.
2. Press the [MENU] key to open the menu.
3. Operate the trackball to select “7.
WATCHMAN” .
4. Press the [RANGE] key to select a transmission interval.
5. Press the [MENU] key to actuate the watchman mode. The indication “WATCH-
MAN” appears and the radar transmits for one minute and then turns to stand-by, and “ECHONOMY” lights.
Note: The antenna radiator does not rotate in the “ECHONOMY” (stand-by) mode. However, the radiator rotates continuously during the watchman mode.
6. The radar automatically starts transmitting after the time selected at step 4 has passed. It transmits for one minute approximately and examines the guard zone for change.
(a) If the condition is unchanged, the radar automatically returns to stand-by again and continues operating in the watchman mode.
(b) If the condition differs from the previous one, the radar sounds an audible alarm, cancels the watchman mode and transmits continuously.
7. To cancel the watchman mode manually, press any key.
2.26 Plotting
This function plots the movement of other ships relative to your own ship.
Press the [PLOT (A/C RAIN)] control to start plotting. The indication “PLOT” and a timer appear at the top right-hand corner of the screen and movement of all targets is plotted. The timer counts up from 0:01 to 99:59, whereupon the timer indication freezes but plotting continues. Targets initially are updated every 15 seconds. However, you can select intervals of 30 seconds, 1 minute, 3 minutes or 6 minutes through the MENU display (Refer to Chapter 3). The plotting interval (except for 15 seconds) appears to the right of the indication PLOT.
If the range is changed during plotting, plotting begins anew with the newly selected range. To cancel plotting, press the [PLOT] key.
Plotting Interval
(30 sec., 1min.,3min., 6min.)
PLOT
0:25
PLOT 3M
18:25
Timer
Figure 2-14 Plotting Indications
Plot Brilliance
The brilliance of plotted echoes is selectable through the MENU display. Press the [MENU] key and select “5. PLOT BRILLIANCE”.
2.27 Navigation Data Display
Navigation data can be displayed on the screen if your radar receives navigation input form a Loran-C, NNSS (satellite navigator) or GPS navigator whose output formats is IEC 61162 or FURUNO CIF. Data displayable include own ship’s position in latitude and longitude (or Loran-C time differences (TDs)), bearing and range to a waypoint selected on the nav aid, own ship’s speed, heading and course, In addition, if a heading sensor or gyrocompass is also connected, a line connects a waypoint (selected on navaid), denoted by a dashed ring, with the own ship’s position.
To return the navigation data display on or off, press the [MENU] key and select “8. NAV
DATA”.
To display TDs instead of L/L, press the
[GAIN] control. Press the control again to restore L/L.
2-11
If the output format is FURUNO CIF a jumper wire must be connected to “JUP1” on the SPU
Board in the display unit. Note that for CIF format the bearing measurement method
(Magnetic or True) does not appear for bearing to waypoint data.
MAG 115.0°
12
NM
3.0NM
GUARD
IR
Waypoint
Own ships position
(latitude and longitude)
Ship's heading
LL
34°38.99S
WP
6.0 NM
SPD
4.3 KT
135°19.22E
171.6° M
HD 115.0° CRS 118.0°
EBL
48.1°R
315.1° R
9.05 NM
VRM
2.62 NM
Range to Waypoint
Bearing to Waypoint
M:Magnetic
T:True
(M or T appear in CIF format.)
Ship's speed
Ship's course
Figure 2-15 Navigation Data on the Screen
2-12
3. 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.
3.1 Multiple Echoes
Multiple echoes occur when a short range, strong echo is received from a ship, bridge, or breakwater. A second, a third or more echoes may be observed on the display at double, triple or other multiples of the actual range of the target as shown in Figure 4-1.
Multiple reflection echoes can be reduced and often removed by decreasing the sensitivity or properly adjusting the A/C SEA.
True echo
3.2 Side-lobe Echoes
Every time the scanner 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 4-2.
Side-lobes show usually only at short ranges and from strong targets. They can be reduced through careful reduction of the sensitivity or proper adjustment of the A/C SEA.
True echo
Main-lobe
Side-lobe
Sprious target
Antenna
Figure 3-2 Side-lobe echoes
Own ship
Multiple echo
Figure 3-1 Multiple echoes
3-1
3.3 Indirect Echoes
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 scanner by the same indirect path. The echo will appear on the same bearing of the reflected surface, but at the same range as the direct echo. Figure
4-3 illustrates the effect of an indirect echo.
Indirect echoes may be recognized as follows:
• they usually occur in a shadow sector
• they appear on the bearing of the obstruction but at the range of the legitimate contact
• when plotted, their movements are usually abnormal, and
• their shapes may indicate they are not direct echoes.
Direct path
Target
Heading marker
3.4 Blind and Shadow Sectors
Funnels, stacks, masts, or derricks in the path of antenna may reduce the intensity of the radar beam. If the angle subtended at the antenna is more than a few degrees a blind sector may be produced. Within the blind sector small targets at close range may not be detected while larger targets at much greater ranges may be detected. See Figure
4-4.
Figure 3-4 Blind and shadow sectors
Indirect path
Indirect path
Scanner
Obstruction
(mast, funnel.
etc.)
Target
Direct path
Indirect echo
Own ship
Heading marker
True echo
Bridge
True echo
Indirect echo
Figure 3-3 Indirect echoes
Indirect echo
3-2
3.5 SART (Search and Rescue
Transponder)
A Search and Rescue Transponder (SART) may be triggered by any X-Band (3 cm) radar within a range of approximately 8 n.miles.
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
µ s) through the band before beginning a relatively slow sweep (7.5
µ s) through the band back to the starting frequency. This process is 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.
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.
Showing SART marks on the radar display
To show the SART marks only on the radar display, detune the radar receiver manually.
This erases or weakens all normal radar echoes, but, the SART marks are not erased because the SART response signal scans over all frequencies in the 9 GHz band. When the radar approaches the SART in operation, the
SART marks will enlarge to large arcs, blurring a large part of the screen. Reduce the sensitivity and adjust the sea clutter control of the radar.
Summary to detect SART response
1. Use 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.
Screen A: When SART
is distant
Echo of SART
24 NM
Screen B: When SART
is close
Lines of 12 dots are displayed in concentric arcs.
Radar antenna beamwidth
1.5 NM
Echo of
SART
Position of
SART
Own ship's position
9500 MHz
9200 MHz
SART mark length
7.5
µ s
Sweep time
95
µ s
Own ship's position
Position of
Radar receiver bandwidth
SART
Sweep start
Low speed sweep signal
High speed sweep signal
Figure 3-5 SART display
General remarks on receiving SART
Radar range scale
When looking for a SART it is preferable to use either the 6 or 12 nautical mile range scale. This is because the total displayed length of the SART response of 12 (or 24) dots may extend approximately 9.5 nautical miles beyond the position of the SART and it is necessary to see a number of response dots to distinguish the SART from other responses.
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 mush 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.
3-3
4. MAINTENANCE & TROUBLESHOOTING
This chapter tells you how to keep your radar in good working order. Before reviewing this chapter please read the safety information which follows.
DANGER
Turn off the power before performing any maintenance or troubleshooting procedure.
4.1 Preventive Maintenance
Regular maintenance is important for good performance. Always keep the equipment as free as possible from dirt, dust, and water splashes. Make sure all screws securing the components are properly tightened.
A maintenance program should be established and should at least include the items listed in Table 4-1.
Hazardous voltages can shock, burn or cause death.
Only qualified personnel totally famillier with electrical circuits should work inside the units.
RF RADIATION HAZARD
The radar scanner emits high frequency radio radiation which can be harmful, particularly to your eyes.
Never look directly into the scanner from a distance of less than two feet when the radar is in operation as you could injure the cornea of your eyes. Always make sure the radar is set to stand-by or is turned off before starting work on the scanner unit.
4.2 Replacing the Fuse
The fuse on the rear panel of the display 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 the equipment may result and void the warranty.
12V: 10A fuse
24/32V: 5A fuse
CAUTION
Use the proper fuse.
Use of a wrong fuse can result in equipment damage.
Table 4-1 Recommended maintenance program
P
3
e
t
r i
o
o d
6 m o n t h s
6 t o m o n t h s
1 y e a r
I t e m
E x p o s e d n u t s b o l t s a n d o n s c a n n e r u n i t s r a d
D c c a i s n n e r i a p l t a o r y o n n e c u n i t o r s t
C
R
h e
C h e e c k p l
c k
a c
p o i
f o r e c o r r o d e d .
n t
c o r r o d e d t h e m o r l o o s e n e d n u t s c l e a n a n d a n d b o l t s .
r e p a i
I f n t n e c e s s a r y , t h e m t h i c k l y .
i f h e a v li y
R e m a r k s
i
S e n s a t e il n g a d c o m o f p a p i o u n t .
n d
A p m a y p l y a b e s m u a s ll e d a m o a n d u b n o l t t o f s g f o r r e e a s e a s y b e t w r e m o e e n v a l n u t s i n f u t u r e .
C h e c k r a d i a t o r f o r d s u r f i r t a c a e n
.
d
T c h i r a c k c k s d i r t o n s h o u l d b e w i p e d o f f w i t h s o f t c l o t h d a m c a r a m c o p e k u i n s t n e f o o f d u s w i t h n e d a
, il a n f r e p p g s l h y w a a s t e r .
il g h t
I f c o m p o u n d a o r a d h e s i v e r e m e d y , a s t h e n a t e c a ll m f p o o r r a r y r e p a i r .
D o n
( a c e t o t o n u s e e ) p f o r l a c s t i c l e a n s o l v i n g .
e
I f n t y o u n e e u n i t , d t o u s e r e m o v e a w t p l h a e s t i c u n i t h e a d m a y o h c o d i c e e n a m m e r .
a u s e f r o m a n t e n n a h a m m e r o r o n w
C a t r e r a c k i n g r e s s , d a m a g e s c a u s i n g t o i n t e s e r n a l r i o u s c i r c u i t s .
C h e c k f o r c o r r o s i o n .
t i g h t c o n n e c t i o n a n d I f f o r c o r r o d e d , r e p l a c e c m e o n n t .
t a c t y o u r d e a l e r
4-1
4.3 Troubleshooting
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.
Table 4-2 Troubleshooting table t
[
I f .
.
.
y o u
[ P O p r e s
W E R s
] e k d e t h e y t o o n t h e r a d a r t u r n t h e w a r m e d p y o u
R o f f a h r
T e
X e
A s
I N k e
] r a d a r s g h a v e a i n a d w i t h j u
A s t e d
/ C y k e i e d a n d s y u p t h e t o a n d y o u t r a n s m i t p h
A / C r e a s s s
S E A e d t
B
n
u
h e o t
t .
.
.
c o n t r o l il g h t p a n e l d o e s
T h e n .
.
.
•
•
• t r il g y h a d t i n j u s g o t i n n g t h e t h e O c
T o n t r o l
H E R S p a n e l m e n u b
.
a c k b a t t e r y c h e c k f m a y u s e i n h a v e p o w d e r i s c c h a r g e d .
a b l e .
• t r y a d j u s t i n g t h e b r li il a n c e .
n o t h i n g t h e d i s a p p l a y p e a r o r d s i s o n p l a y c o n t r a s t i s p o o r c h a r a c t e r s d i s t o r t e d a r e • r e q u e s t s e r v i c e .
t h e s c a n n e r r o t a t e d o e s n o t c h a r a c t e r s i n d i c a t i o n s a b n o r m a l a n d a r e
•
• t h e p r o b l e m
R e q u e s t h a v e s e t .
a s e r v m a q u a il f i e d y i c e .
b e i n s c a n n e r t e c h n i c i a n c h e u n i t .
c k t h e t n a e r i t g h e
( i n d i c e t s r a t i n o i s e o n s n o r a p p e a r a n d m a r k e r s d o )
• c h e c k s i g n a l c a b l e f o r d a m a g e n a e n i d t m a r h k e e r t a r r s i n d i c a t i o n s n o r
( n o i s e g e a p p e a r t s d o )
• c h e c k s i g n a l c a b l e f o r d a m a g e .
.
t h e s w e s w e e p e p i n g
( r a d i a l a r o u n d d i s p l a s y n c h r y ) o n i s i z n o t e d w i t h il n e t h e s c a n n e r r o t a t i o n t h e r e i s n o s e n s i t i v i t y c h a n g e i n n o t h i n g h a p p e n s
•
•
• t h e u n i t .
p r o b l e m
R e q u e s t r e k q u e s t e y m a y s e r b e m a y s e v i c e .
r v i c e .
f a u l t y .
b e i n t h e
R e q u e s t s c a n n e r s e r v i c e .
4-2
4.4 Life Expectancy of
Magnetron
The following table shows the life expectancy of the magnetrons.
Table 4-3 Life expectancy of magnetrons
M a g n e t r o n T y p e
M
E
G
3 5
5
7
2
1
4 8
C o d e N o .
L i f e e x p e c t a n c y
0 0 0 1 1 6 1 2 1
0 0 0 1 3 7 5 2 9
2 , 0 0 0 3 , 0 0 0 h o u r s
( I n c l u d i n g s t a n d b y )
4-3
SPECIFICATIONS OF MARINE RADAR
MODEL 1761 MARK-3
1. GENERAL
1.1. Indication System PPI Daylight display, raster scan, 8 tones in monochrome
1.2. Range, Pulselength (PL) & Pulse Repetition Rate (PRR)
PL PRR
Range (nautical miles)
1.3. Range Resolution 41 m
1.5. Minimum Range
1.6. Bearing Accuracy
39 m (0.25 NM range)
Within 1º
1.7. Range Ring Accuracy 0.9 % of range or 8 m, whichever is the greater
2. ANTENNA UNIT
2.1. Radiator
2.2. Polarization
Slotted waveguide array
Horizontal
2.3. Antenna Rotation Speed 24 rpm or 48 rpm nominal
2.4. Radiator Length 100 cm (XN-10A)
2.6. Vertical 27°
2.7. Sidelobe Attenuation Within ±20° of main-lobe: less than -24 dB
Outside ±20° of main-lobe: less than -30 dB
3. TRANSCEIVER MODULE
3.1. Frequency
3.2. Modulation
3.3. Peak Output Power
3.4. Modulator
9410 MHz ±30MHz (X band)
P0N
4 kW nominal
FET Switching Method
3.5. Intermediate Frequency 60 MHz
3.6. Tuning
3.7. Receiver Front End
3.8. Bandwidth
3.9. Duplexer
Automatic
MIC (Microwave IC)
Tx pulselength 0.08
µs and 0.3 µs: 7 MHz
Tx pulselength 0.8
µs: 3 MHz
Circulator with diode limiter
SP - 1
E3481S01B
4. DISPLAY UNIT
4.1. Indication System
4.2. Picture Tube
PPI Daylight display, raster scan, 8 tones in monochrome
7 inch rectangular monochrome CRT
Effective display area more than 100 mm
4.3. Range, Range Interval, Number of Rings
4.1. Markers of 2 4 3 4 3 4 3 4 3 4 4 4 4 4
Heading Line, Bearing Scale, Range Rings,
Variable Range Marker (VRM),
Electric Bearing Line (EBL), Tuning Bar, Cursor, Alarm Zone,
Waypoint Mark (navigation input required),
North Mark (heading sensor input required)
4.2. Alphanumeric Indications Range, Range Ring Interval, Interference Rejection (IR),
Stand-by (ST-BY), Radar Alarm (G(IN), G(OUT), G(ACKN)),
Range, Bearing and Latitude/Longitude of Cursor,
Echo Stretch (ES), Echo Plot (PLOT), Plot Elapsed Time,
Navigation Data (navigation input required),
4.3. Input Data
Own ship’s position:
4.4. Output Data
NMEA0183 (Ver.1.5/2.0), current loop
GGA>RMA>RMC>GLL (accept GLL in NMEA Version1.5 only)
Speed: RMA>RMC>VTG>VHW
Heading (True): HDT>HDG
*1
>HDM
*1
>VHW>VHW
*1
Heading (Magnetic): HDM>HDG
*1
>HDT
*1
>VHW>VHW
*1
Course (True):
Course (Magnetic):
RMA>RMC>VTG
VTG>RMC>RMA
Waypoint (Range, Bearing): RMB>BWC>BWR
Loran time difference: RMA>GLC>GTD
*1: calculated by magnetic drift.
NMEA 0183 (Version 1.5/2.0), RS-422
5. ENVIRONMENTAL CONDITION
5.1. Ambient Temperature Antenna Unit: -25°C to +70°C
5.2. Relative Humidity
5.3. Waterproofing
Display Unit: -15°C to +55°C
95 % or less at +40°C
Antenna Unit: IPX6
Display Unit: IPX4
6. POWER SUPPLY & POWER CONSUMPTION
6.1. Power Supply
6.2. Voltage and Current
6.3. Power Consumption
12-32 VDC (10.2 to 40.0 VDC), 58 W approx.
XN-10A (24rpm): 12 VDC: 4.5 A, 24 VDC: 2.0 A, 32 VDC: 2.0 A
XN-10A (24rpm): 70 W to 90 W (100 kt)
SP - 2
E3481S01B
7. COATING COLOR
7.1. Display Unit Panel: N3.0, Chassis: 2.5GY5/1.5
N9.5
8. COMPASS SAFE DISTANCE
Standard: 0.50 m Steering: 0.40 m
Standard: 1.00 m Steering: 0.75 m
SP - 3
E3481S01B
A
A/C RAIN control .................................... 2-4
A/C SEA control .................................... 2-3
B
Bearing measurement ............................. 2-5
Blind sectors ............................................ 3-2
Brilliance ........................................... 2-2, 2-8
BRILL key ................................................ 2-2
E
EBL ........................................................ 2-5
Echo stretch ............................................ 2-8
Economy mode ....................................... 2-2
F
Fuse ........................................................ 4-1
G
Gain control ............................................. 2-2
Guard alarm .......................................... 2-9
Guard key ................................................ 2-9
Guard zone ............................................. 2-9
H
I
Heading marker ....................................... 2-4
Indirect echoes ........................................ 3-2
Interference ........................................... 2-8
M
Magnetron .............................................. 4-3
Maintenance ............................................ 4-1
Multiple Echoes ....................................... 3-1
Menu tree .................................................. v
N
Navigation data .................................... 2-11
Noise ....................................................... 3-8
North marker ........................................... 2-4
P
Plotting interval ....................................... 2-11
Plotting timer .......................................... 2-11
POWER key ............................................ 2-2
Power on/off ............................................ 2-2
R
Range key ............................................... 2-2
Range measurement ............................... 2-5
Range rings ............................................. 2-5
Index
S
SART ....................................................... 3-2
Sensitivity ................................................ 2-2
Shadow Sectors ...................................... 3-2
Side-lobe Echoes .................................. 3-1
Stand-by .................................................. 2-2
ST BY/TX key .......................................... 2-2
System configuration ................................. vii
T
Transmitting ............................................ 2-2
Troubleshooting .................................... 4-2
V
VRM ........................................................ 2-5
W
Watchman ............................................. 2-10
Z
Zoom ....................................................... 2-6
IN-1

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Key features
- Compact size
- Lightweight
- Durable brushless antenna motor
- On-screen alphanumeric readout
- Standard features: EBL, VRM, Guard Alarm, Display Off Center, Echo Trail
- Watchman feature
- Navigation Data Display
- Zoom feature