Onwa KR-1338C v.1 User Manual
KR-1338/1668
OPERATOR'S MANUAL
KR-1338/1668
10.4 TFT LCD COLOR MARINE RADAR
SAFETY INSTRUCTIONS
"DANGER","WARNING" and "CAUTION" notices throughout this manual. It is the
responsibility of the operator and the installer of the equipment to read, understand and
follows these notices. If you have any questions regarding these safety instructions,
please contact a ONWA agent or dealer.
WARNING
Do not open the equipment.
Hazardous voltage which can cause electrical shock, burn or serious injury exists
inside the equipment. Only qualified personnel should work inside the equipment.
Wear a safety belt and hard hat when working on the antenna unit.
Serious injury or death can result if someone falls from the radar antenna mast.
Stay away from transmitting antenna.
The radar antenna emits microwave radiation which can be harmful to the human
body, particularly the eyes. Never look directly into the antenna radiator from a
distance of less than 1 m when the radar is in operation.
Turn off the radar power switch before servicing the antenna unit. Post a
warning sign near the switch indicating it should not be turned on while the
antenna unit is being serviced.
Prevent the potential risk of someone begin struck by the rotating antenna and
exposure to the RF radiation hazard.
Do not disassemble or modify the equipment.
Fire electrical shock or serious injury can result.
Turn off the power immediately if water leaks into the equipment or the equipment is
emitting smoke or fire.
Continued use of the equipment can cause fire or electrical shock.
Do not place liquid-filled containers on the top of the equipment.
Fire or electrical shock can result if a liquid spills into the equipment.
CAUTION
Use the proper fuse.
Use of a wrong fuse can result in fire or permanent equipment damage.
Do not use the equipment for other than its intended purpose.
Personal injury can result if the equipment is used as a chair or stepping stool, for example.
Do not objects on the top of the equipment.
The equipment can overheat or personal injury can result if the object falls.
TABLE OF CONTENTS
FOREWORD 1
Features 1
Model KR-1338 SPECIFICATION 2
Model KR-1668 SPECIFICATION 4
CONFIGERATION OF KR-1338/1668 8
1. PRINCIPLE OF OPERATION 9
1.1 What is Radar? 9
1.2 How Ships Determined Position Before Radar 9
1.3 How Radar Determines Range 9
1.4 How Radar Determines Bearing 9
1.5 Radar Wave Speed and Antenna Rotation Speed 9
1.6 The Radar Display 10
2. BASIC OPERATION 11
2.1 Control Description 11
2.2 Display Indication and Markes 12
2.3Turning the Radar On and Off
2.4 Transmitting 13
2.5 Stand-by 13
2.6 Selecting the Range 14
2.7 Adjusting Picture Brilliance 14
2.8 Setup display color 15
2.9 Adjusting Receiver Sensitivity 16
13
2.10 Adjusting the A/C SEA Control (reducing sea clutter) 16
2.11 Apply the A/C RAIN (reducing rain clutter) 18
2.12 Erasing the Heading Line, North Mark 18
2.13 Measuring the Range 19
2.14 Measuring the Bearing 20
2.15 Using the Offset EBL 21
2.16 Shifting (off centering) the Pcture 23
2.17 Zoom 23
3. MENU OPERATION 25
3.1 Basic Menu Operation 25
3.2 Selecting the Presentation Mode 25
3.3 Magnifying Long Range Echoes (echo stretch) 26
3.4 Echo Trail 27
3.5 Suppressing Radar Interference 28
3.6 Selecting Pulsewidth 29
3.7 Guard Alarm 30
3.8 Watchman 32
3.9 Display Navigation Data 33
3.10 OTHER MENU Description 34
3.11 Function Keys
3.12 Suppressing Noise 36
3.13 Adjusting Brilliance of Markers 36
3.14 Outputting Target Position 36
35
4. FALSE ECHOES 37
4.1 Multiple Echoes 37
4.2 Side-lobe Echoes 37
4.3 Indirect ECHOES 38
4.4 Blind and Shadow Sectors 39
5. MAINTENANCE & TROUBLESHOOTING 40
5.1 Preventative Maintenance 41
5.2 Replacing the Fuse 41
5.3 Troubleshooting 41
5.4 Self Test 41
5.5 Life Expectancy of Magnetron 43
6. INSTALLATION 44
6.1 Antenna Unit Installation Sitting handling considerations 44
6.2 Display Unit Installation Mounting considerations 52
6.3 Exchange of Fuse for 24/32V Power Supply 54
6.4 Checking the Installation 54
6.5 Adjustments 54
MENU TREE 60
ARPA 61
KR-1338/1668 OUTSIDE DRAWING 71
KR-1338/1668 INTERCONNECTION 74
FOREWORD
Thank you for your choice of ONWA MODEL KR-1338/1668 Marine Radar. The
radar is designed and constructed to meet the rigorous demands of the marine environment. However, no machine can perform its intended function unless properfly
installed and maintained. Please carefully read and follow the recommended procedures for installation, operation and maintenance. While this unit can be installed
by the purchaser, any purchaser who has doubts about his or her technical abilities
may wish to have the unit installed by a ONWA representative or other qualified
techician. The importance of a through installation can not be overemphasized.
We would appreciate hearing form you, the end user, about whether user, about
user, about whether we are achieving our purposes. Thank you for considering and
purchasing ONWA equipment.
Features
Your radar has a large variety of functions, all contained in a remarkably small
cabinet.
The main features of the MODEL KR-1338 are.
Traditional ONWA reliability and quality in a compact, lightweight and low-cost
radar.
Durable brushless antenna motor.
On-screen alphanumeric readout of all operational information.
Standard features include EBL (Electronic Bearing Line), VRM (Variable Range
Marker), Guard Alarm, Display Off Center, and Echo Trail.
Watchman feature periodically transmits the radar to check for radar targets
which may be entering the alarm zone.
Ship s position in latitude and longitude and range and bearing to waypoint,
and ship's speed/ heading/course can be shown in the ottom text area.(Requires
a navigation aid which can output such data in IEC 1162 format.)
Zoom feature provided.
1
KR-1338 SPECIFICATION
ANTENNA UNIT
1. Radiator : Slotted waveguide array
2. Radiator length : 55 cm
3. Horizontal beamwidth : 4
4. Vertical beamwidth : 25
5. Sidelobe :
Within 20 off mainlobe; less than -18 dB
Outside 20 off mainlobe; less than -23 dB
6. Polarization : Horizontal
7. Antenna rotation speed : 24 rpm( 2)
8. Wind resistance : Relative wing speed 100 knots(51.5 m/s)
TRANSCEIVER MODULE
(contained in radome)
1. Transmitting tube : MSF1421B or MAF1421B
2. Frequency : 9410 MHz 30MHz
3. Peak output power : 4kW nominal
4. Pulselength & pulse repetition rate :
0.08 S, 2100 Hz (0.125, 0.25, 0.5, 0.75, 1.5nm)
0.3 S, 1200 Hz (1.5, 2, 3nm)
0.8 S, 600 Hz (3, 4, 6, 8, 12, 16, 24, 36nm)
5. Warm up time : 1:30 minutes
6. Modulator : FET switching method
7. I.F. : 60MHz
8. Tuning : Automatic or manual
9. Receiver front end : MIC (Microwave IC)
10. Bandwidth :
Tx pulselength 0.3 S and 0.08 S : 25MHz
Tx pulselength 0.8 S : 3MHz
11. Duplexer : Circulator with diode limiter
2
DISPLAY UNIT
1. Indication system : LCD digital display
2. Display : 10.4 LED backlight, 32-bit TFT Color LCD Display
3. Range scale (nm) :
Range, Range interval and no. of Rings:
0.125(0.0625,2), 0.25(0.125,4), 0.75(0.25,3), 1(0.25,4), 1.5(0.5,3), 2(0.5,4),
3(1,3), 4(1,4), 6(2,3), 8(2,4), 12(3,4), 16(4,4), 24(6,4), 36(12,3)
4. Bearing resolution : 4
5. Bearing accuracy : Within 1
6. Range discrimination : Better than 30 m
7. Range ring accuracy : 0.9% or range in use or 8 m, whichever is larger
8. Minimum range : Better than 25 m
9. Markers :
Heading line, Bearing scale, Range ring, VRM, EBL Tuning indicator,
Cursor, Alarm zone, North mark (heading sensor input required)
10. Alphanumeric indication :
Range, Range ring interval, Pulselength, Interference rejection (IR), VRM,
EBL, Stand-by (ST-BY), Radar alarm, Echo stretch (ES), Range to cursor,
Bearing to cursor, Echo trailing (TRAIL), Trail time, Trail elapsed time,
Navigation data (navigation input required), heading (HDG, heading sensor
input required)
11. Vibration :
Vibration Total amplitude :
1 to 12.5 Hz 1.6mm
12.5 to 25 Hz 0.38mm
25 to 30 Hz 0.10mm
12. Temperature :
Antenna unit; -25 to + 70
Display unit; -10 to + 50
13. Humidity :
Relative humidity 93% or less at + 40
14. Power supply & power consumption : 12V, 24V or 32VDC (10.5V to 40
VDC) 60W
15. Compass safe distance :
Display unit 0.75m 0.6m
Standard Compass
Steering Compass
1.75m3.1mAntenna unit
3
KR-1668 SPECIFICATION
ANTENNA UNIT
1. Radiator : Slotted waveguide array
2. Radiator length : 120 cm
3. Horizontal beamwidth : 1.9
4. Vertical beamwidth : 22
5. Sidelobe :
Within 20 off mainlobe; less than -24 dB
Outside 20 off mainlobe; less than -30 dB
6. Polarization : Horizontal
7. Antenna rotation speed : 24 rpm
8. Wind resistance : Relative wing speed 100 knots(51.5 m/s)
TRANSCEIVER MODULE
(contained in antenna)
1. Transmitting tube : MAF1421 or MSF1421
2. Peak output power : 4kW nominal
3. Pulselength & pulse repetition rate :
0.08 S, 2100 Hz (0.125, 0.25, 0.5, 0.75, 1.5nm)
0.3 S, 1200 Hz (1.5, 2, 3nm)
0.8 S, 600 Hz (3, 4, 6, 8, 12, 16, 24, 36, 48, 64nm)
4. Bandwidth :
Tx pulselength 0.3 S and 0.08 S : 25MHz
Tx pulselength 0.8 S : 5 MHz
5. Other : See KR-1338
4
DISPLAY UNIT
1. Range scale (nm) :
Range, Range interval and no. of Rings:
0.125(0.0625,2), 0.25(0.125,4), 0.75(0.25,3), 1(0.25,4), 1.5(0.5,3), 2(0.5,4),
3(1,3), 4(1,4), 6(2,3), 8(2,4), 12(3,4), 16(4,4), 24(6,4), 36(12,3), 48(12,4),
64(16,4)
2. Compass safe distance :
Standard Compass
Steering Compass
Display unit 0.75m 0.6m
0.74m1.0mAntenna unit
3. Power supply & power consumption : 12V, 24V or 32VDC (10.5V to 40VDC)
60W
5
INTERFACE IEC 1162(NMEA0183)
(Input)
Own ship`s position: GGA>RMA>RMC>GLL
Speed: RMA>RMC>VIG>VHW
Heading (True): HDT>HDG*>HDT*>VHW>VHW*
Course (True): RMA>RMC>VTG
Course (Magnetic): VTG>RMA*>RMC
Waypoint (Range, Bearing): RMB>BWC>BWR
Loran time difference: RMA>GLC>GTD
Water depth: DPT>DBT
Water temperature: MDA>MTW
XTE: RMB>XTE>APB
*: Calculated value based Magnetic variation.
(Output)
TLL: On using TLL Key.
RSD: An interval of four seconds.
TTM: ARPA
6
ARPA FUNCTION( )Require Heading Data Input
1. Acquisition
Instant selection of auto or manual acquisition in 0.2 ~ 16nm, relative
speed 100KT.
2. Tracking
Automatic tracking of up to 10 acquired targets betwen 0.1 to 16 nm.
3. Prediction of target motion
True or relative vectors, time scaled.
4. Past position
10 past positions of tracked targets.
5. Alarm Lost target. CPA/TCPA
6. Automatic tracking range
0.1 ~ 16nm
7. Target information (one target selected)
Distance and bearing from own ship to target
Moving direction and speed
CPA (estimated Closest Time to CPA)
8. Vector length 30 sec.~30 min.
9. Plotting interval 15 sec.~6 min.
7
CONFIGERATION OF KR-1338/1668
ANTENNA UNIT
Antenna cable
KRC-003-10/15/20
10/15/20m
Pin
Pin
Display UNIT
8
1. PRINCIPLE OF OPERATION
1.1 What is Radar?
The term "RADAR" is an acronym meaning "RAdio Detection And Ranging".
Although the basic principles of radar were developed during World War II,
echoes as an aid to navigation is not a new development.
1.2 How Ships Determined Position Before Radar
Before the invention of radar, when running in fog near a rugged shoreline,
ships would sound a short blast on their whistles, fire a shot, or strike a bell.
The time between the origination of the sound and the returning of the echo
indicated how far the ship was from the cliffs or the shore. The direction from
which the echo was heard indicated the relative bearing of the shore.
1.3 How Radar Determines Range
Radar determines the distance to the target by calculating the time difference
between the transmission of a radar signal and the reception of the reflected
echo. It is a known fact that radar waves travel at a nearly constant speed of
162,000 nautical miles per second. Therefore the time required for a transmitted
signal to travel to the target and return as an echo to the source is a measure
of the distance to the target. Note that the echo makes a complete round trip,
but only half the time of travel is needed to determine the one-way distance to
the target. This radar automatically takes this into account it making the range
calculation.
1.4 How Radar Determines Bearing
The bearing to a target found by the radar is determined by the direction in
which the radar scanner antenna is pointing when it emits an electronic pulse
and then eceives a returning echo. Each time the scanner rotates pulses are
transmitted in the full 360 degree circle, each pulse at a slightly differentbearing
from the previous one. Therefore, if one knows the direction in whichthe signal
is sent out, one knows the direction from which the echo must return.
1.5 Radar Wave Speed and Antenna Rotation Speed
Note that the speed of the radar waves out to the target and back again as echoes
is extremely fast compared to the speed of totation of the antenna. By the time
radar echoes have returned to the scanner, the amount of scanner rotation after
initial transmitting of the radar pulse is extremely small.
9
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.
Targets
Own ship
(radar)
(A) Bird's eye view of situation (B) Radar picture of (A)
Own ship
in center
Heading line
Figure 1-1 How radar works
Range and bearing of
a target, relative to own
ship, are readable on
the PPI
10
2. BASIC OPERATION
2.1 Control Description
Brief press:
Displays the data of target
selected with the cursor
Long press:
Terminates plotting of the target
selected with the cursor.
Opens/closes menus.
Selects
EBL1/EBL2/VRM1/VRM2
Control:
Adjusts sensitivity.
Switch:
Temporarily erases heading
line (and north mark if displayed).
Control:
Reduces sea clutter.
Switch*:
(Long press) Shifts your vessel`s
position to cursor location.
(Brief press) Doubles size of
area between your vessel and
location selected by cursor.
Control:
Reduces rain clutter.
Switch*:
Displaces the EBL origin.
Lights when the economy mode
is on.
Omnipad
Shifts cursor, VRM and EBL;
select items and options on
menu.
(1) Acquires the target selected
with the ominipad.
(2) Registers selection on
menus.
Sets guard zone area.
Sets radar range.
Enables/erases
EBL1/EBL2/EBL3/EBL4.
Outputs target position data.
Automatically reduces sea and
rain clutters.
Adjusts display brilliance.
Sets radar in stand-by;
transmits radar pulse.
Turns power on/off.
*Default switch function.
Figure 2-1 Control panel
11
2.2 Display Indication and Markers
Echo trail elapsed time
Heading (requires heading data)
Range
Range ring interval
Pulselength
Display mode
Cursor
Guard zone
EBL1
VRM1
Heading line
.125NM
.0625
SP
HU
HDG
234.5
TRAIL
25:38
AUTO
30M
G OUT
*
ZOOM
ES
OFFCENTER
Tuning indicator
Echo trail time
Guard zone
Zoom
Echo Stretch
Off center
EBL2
Range ring
VRM2
North mark
A/C AUTO
EBL1 bearing
EBL2 bearing
A/C
AUTO
EBL
R
345.6
23.0
R
1.5 NM
13.5
0.06
NM
R
0.142
Cursor bearing
Cursor range
Figure 2-2 Display indications
IR2
VRM
0.048NM
0.100NM
Interference rejector
VRM1 range
VRM2 range
12
2.3 Turning the Radar On/Off
Press the [POWER] key to turn the radar on or off.
The control panel lights and a timer displays the time remaining for warm up of
the magnetron (the device which produces radar pulses), counting down from 1:30
to 0:01.
2.4 Transmitting
After the power is turned on and the magnetron has warmed up, STAND-BY
appears at the screen center. This means the radar is now fully operational. In
stand-by the radar is available for use at anytime - but no radar waves are being
transmitted. Press the [ST-BY/TX] key to transmit. When transmitting, any echoes
from targets appear on the display. This radar displays echoes in eight tones of
green according to echo strength.
2.5 Stand-by
When you won't be using the radar for an extended period, but you want to keep
it in a state of readiness, place it in stand-by by pressing the [ST-BY/TX] key.
The display shows "STAND-BY,"navigtion data, or goes into the economy
mode depending on menu setting. (More on menu operation later.)
Economy mode
The CRT can be set to automatically turn itself off when in stand-by, to reduce
power consumption. This feature is called the "economy mode." Power consumption in the economy mode is 28W. When economy mode is no, the lamp next to the [POWER] key lights.
Navigation data display during stand-by
If a navigation aid inputs navigation data to this radar, navigation data can be
displayed during stand-by. You can turn the navigation data display on/off through the menu. Figure 2-3 shows a typical navigation data display during standby.
Note 1:Availability of a particular display item depends on incoming data.
Note 2:When Range to Waypoint reaches 0.1nm, the WPT mark jumps to dead
ahead even though a difference may exist between heading and BRG to WPT.
Note 3:When cross track error exceeds 1 nm on either side, the XTE mark starts blinking.
13
Speed
Depth
To Waypoint
bearing heading
Time-to-go to
TO Waypoint
Bearing TO Waypoint
Range to TO Waypoint
SPEED
DEPTH
Heading
N
L XTE
10.5
125
TRIP
Kt
TEMPERATURE
m
E
HDG
092.5
180.0 M
CRS
TTG
WPT
BRG 45.0 M
RNG 12.0NM
OWN SHIP
LAT 30 00. 00N
LON 135 00.00E
XTE
R 0.3NM
W
000.3nm
+17.3
01:08
ST-BY
Time-to-go to Stand-by
Trip distance since power on
Course
S
Ship s position in
'
latitude and longitude
Cross Track Error
Mark
XTE R
direction and amount
of error.
" " shows
1.0 1.0
0.5 0.5
Figure 2-3 Typical navigation data display
during stand-by
2.6 Selecting the Range
The range selected automatically determines the range ring interval, the number
of range rings, pulselecgth and pulse repetition rate, for optimal detection
capability in short to long ranges. You can select which ranges and pulselength
(for 1 mile range) to use through the menu. The range, range ring interval and
pulselength appear at the botton left-hand corner of the display.
To select a range;
When navigating in or around crowded harbors, select a short range to watch for
possi ble collision situations.
If you select a lower range while on open water, increase the range occasionally
to watch for vessels that may be heading your way.
2.7 Adjusting Picture Brilliance
The [BRILL] key adjusts the brilliance of the radar picture in eight levels.
Press the [BRILL] key to set the brilliance level.
The current level momentarily appears on the screen.
14
2.8 Setup display color
In order to adapt to the different environments, the radar echo display the background color and echo color can be set by users themselves, there are five kinds of
background colors and three kinds of echo colors available. Setting methods are
as follows:
1.By menu
1) Press [MENU] key open main menu;
2) Select ''OTHER MENU'' and press [ACQ/ENTER] key;
3) Press [ ]or [ ] key select ''22.Color setting'' & press [ACQ/ENTER] key
open the color setup menu;
Color setting
Background setting
Black/green
Black/red Blut/white
DK blue/white White/green
2.Echo Color Yellow Green
Press [MENU] key to escape
4) Press [ ] or [ ]key select ''Background Color'' or ''Echo Color'',use [ ] or
[ ] select color desired and press [ACQ/ENTER] key ;
5) Press [MENU] key to close the menu.
2.Using the function key
The function keys [ F1 ] function default setting for ''Background Color'' ,[F2]
key default setting for ''Echo Color''. Directly on the keyboard you can press
these two keys select the desired color setting.
15
2.9 Adjusting Receiver Sensitivity
The [GAIN] control adjusts the sensitivity of the receiver. It works in precisely
the same manner as the volume control of a broadcast receiver, amplifying the
signals received. The proper setting is such that the background noise is just
visible on the screen. If you set up for too little sensitivity, weak echoes may
be missed. On the other hand excessive sensitivity yields too much background
noise; strong targets may be missed because of the poor contrast between desired
echoes and the background noise on the display. To adjust receiver sensitivity,
transmit on long range, and adjust the [GAIN] control so background noise is
just visible on the screen.
2.10 Adjusting the A/C SEA Control (reducing sea clutter)
Echoes from waves can be troublesome, covering the central part of the display
with random signals known as "sea clutter." The higher the waves, and the higher
the scanner above the water, the further the clutter will extend. Sea clutter appears
on the display as many small echoes which might affect radar performance. (See
the Figure 2-3.) When sea clutter masks the picture, adjust the A/C SEA control to
reduce the clutter.
How the A/C SEA control works
The [A/C SEA] control reduces the amplification of echoes at short ranges (where
clutter is the greatest) and progressively increases amplification will be normal at
those ranges where there is no sea clutter.
16
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 conRol until clutter has disappeared to leeward, but a little is still visible windward.
1. Confirm that the sensitivity is properly adjusted, and then transmit on short
range.
2. Adjust the [A/C SEA] control so small targets are distinguishable but some
clutter remains on the display.
Sea clutter at
display center
A/C SEA control adjusted;
sea clutter suppressed.
Figure 2-4 How to adjust the STC control
Tip for adjusting the A/C SEA
A common mistake is to over-adjust the circuit so all the clutter is removed. As
an example set up for maximum STC. You will see how the center of the display
becomes dark. This dark zone can be dangerous (targets may be missed),
especially if the sensitivity is not properly adjusted. Always leave a little clutter
visible on the display to be sure weak echoes will not be suppressed. If there is
no clutter visible on the display, turn off the circuit.
17
2.11 Apply the A/C RAIN (reducing rain clutter)
The vertical beamwidth of the antenna is designed to see surface targets even
when the ship is rolling. However, by this design the unit will also detect rain
clutter (rain, snow, hail, etc.) in the same manner as normal targets. Figure 2-4
Shows the appearance of rain clutter on the Display.
Adjusting A/C RAIN
When rain clutter masks echoes, adjust the [A/C RAIN] Control, This control splits up these unwanted echoes into a speckled pattem, making recognition of soild
targets easier.
Appearance of rain clutter A/C RAIN control adjusted;
rain clutter suppressed.
Figure 2-5 Effect of A/C RAIN
Note: In addition to reducing clutter, the [A/C RAIN] control can be
used in fine weather to clarify the picture when navigating in
confined waters. However, with the circuit activated the receiver is
less sensitive. Therefore, turn off the circuit when its function is not
required.
Automatic adjustments of A/C SEA and A/C RAIN
Push the [A/C Auto] key. "A/C Auto"appearstat the bottom left-hand corner of
the display when the A/C AUTO circuit is on. You can fine tune by adjusting the
[A/C SEA], [A/C RAIN] and [GAIN] controls.
2.12 Erasing the Heading Line, North Mark
The heading line or north mark (available with gyrocompass connection) may occasionally mask a target. To view the target, you can temporarily erase the heading
line and north mark by pressing and holding down the [GAIN (HM OFF)] control.
Release the control to re-display the marks.
18
Heading
Line
North mark
Figure 2-6 Heading line and north mark
2.13 Measuring the Range
You can measure the range to a target three ways: by the range rings, by the
cursor, and by the VRM (Variable Range Marker).
By range ring
Count the number of rings between the center of the display and the target.
Check the range ring interval and judge the distance of the echo from the echo
from the inner edge of the nearest ring.
By cursor
Operate the omnipad to place the cursor intersection on the inside edge of the
garget echo, The range to the target, as well as the bearing, appears at the
bottom right-hand corner of the display.
By VRM
1. Press the [EBL/VRM SELECT] key to circumscribe a VRM readout (at the
bottom center).Each press of the key selects the readout of EBL1,EBL2,VRM1
or VRM2 in that order.
EBL
345.6 R
23.0 R
Figure 2-7 Display bottom, showing location
of EBL and VRM readouts
2. Press the [EBL/VRM CONTROL] key enable control of the VRM by the
omnipad.
3. Operate the omnipad to place the outside edge of the VRM on the inside
VRM
5.3 NM
12.5 NM
edge of the target.
4. Check the VRM readout at the bottom right-hand corner of the display to
find the range to the target.
5. To erase the VRM, press and hold down the [EBL/VRM CONTROL] key .
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