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2-16

2.21 Echo Trails

You can show the trails of targets in
afterglow. This function is useful for alerting
you to possible collision situations.

Starting echo trail

Press the [TRAIL] key to start the echo trail
function. Afterglow starts extending from
targets and "TRAIL" and the echo trail time
appear at the top right-hand corner of the
display. Press the key again within 3
seconds to select a different trail time,
among 15 sec, 30 sec, 1 min, 3 min, 6 min,
15 min, 30 min, and continuous. In
continuous plotting the time elapsed
appears at the top right corner on the
display.

Note:

 If the range is changed, trails are

painted anew with the newly selected
range.

True trails

Relative trails

Figure 2-18 Appearance of echo trails

Fixed time trails

When the elapsed time clock counts up to
the trail time selected, the elapsed time
display freezes. The oldest portions of trails
are erased so only the latest trail, equal in
length to the trail time selected, is shown.
Then, trails start extending again. For
example, the one minute trail time is
selected. When the elapsed time display
freezes at 60 seconds, all but the latest one
minute of trails are erased and then trailing
continues.

Continuous trail

The maximum continuous trail time is 99
minutes and 59 seconds. When the
elapsed time clock counts up to that time
the elapsed time display is reset to zero, all
trails are erased and then trailing is
restarted.

Adjusting brilliance of afterglow

The brilliance of the trails' afterglow can be
set on the Backlight/Brilliance menu.

1. Press the [MENU] key.

2. Press the omnipad at 6 o’clock to

select Backlight/Brilliance and press
the [ENT] key.

3. Press the omnipad at 6 o’clock to

select Echo Trail.

4. Select brilliance level, 1 or 2 as desired.

2 is the highest level.

5. Press the [ENT] key followed by the

[MENU] key.

Canceling echo trails

Press the [TRAIL] key to erase the TRAIL
indication.

Summary of Contents for 851 MARK-2

Page 1: ...MARINE RADAR MODEL 851 MARK 2...

Page 2: ...p h o n e 0 7 9 8 6 5 2 1 1 1 Te l e f a x 0 7 9 8 6 5 4 2 0 0 Yo u r L o c a l A g e n t D e a l e r A l l r i g h t s r e s e r v e d P U B N o O M E 3 4 9 0 0 M O D E L 8 5 1 M A R K 2 Y O S H F I...

Page 3: ...hile the antenna unit is being serviced Prevent the potential risk of someone begin struck by the rotating antenna and expo sure to RF radiation hazard WARNING Do not disassemble or modify the equipme...

Page 4: ...rd 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 Navigatio...

Page 5: ...iii MENU TREE A 1 SPECIFICATIONS SP 1 INDEX index 1 Declaration of Conformity...

Page 6: ...emphasized 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 varie...

Page 7: ...Alarm Buzzer OP03 169 Rectifier RU 3423 Navigation Device Echo Sounder Gyro compass Ship s Mains 100 110 115 VAC 200 220 230 VAC 1 50 60 Hz Ship s Mains 12 24 VDC Option MODEL 851 MARK 2 Antenna unit...

Page 8: ...on 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...

Page 9: ...at 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 r...

Page 10: ...s radar range Plots targets trails Opens closes menus Turns the VRM on off Turns the EBL on off ENT MENU ECHO HM OFF RANGE TONE BRILL EBL VRM TRAIL RINGS GUARD OFF CENTER DISP MODE ST BY TX POWER Eras...

Page 11: ...EBL CURSOR 0 675NM 232 5 R 0 681NM 308 7 R AUTO Figure 2 2 Display indications 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 dis...

Page 12: ...utomatically 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 T...

Page 13: ...4 Display for adjustment of GAIN STC A C RAIN and FTC 2 Press the omnipad at 6 o clock 12 o clock to select item to adjust Current selection is circumscribed by dashed rectangle 3 Press the ENT key 4...

Page 14: ...justment 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 c...

Page 15: ...r Figure 2 7 Tuning indicator Note When you switch from manual to automatic wait 4 seconds before closing the MENU Otherwise automatic tuning may not work properly Manual tuning The default tuning met...

Page 16: ...ways to measure the bearing to a target by the cursor and by the EBL Electronic Bearing Line By cursor Operate the omnipad to bisect the target with the cursor intersection The bearing to the target a...

Page 17: ...course with your vessel 2 12 Menu Operation The menu consisting of six sub menus mostly contains less often used functions which once preset do not require regular adjustment To open or close the menu...

Page 18: ...ring the guard zone or OUT alarm to targets exiting the guard zone 4 Selects VRM unit nm km or sm 5 Selects EBL reference relative to the ship s heading or true 6 Selects ranges to use At least two ar...

Page 19: ...the display mode changes in one of the sequences shown below depending on equipment connected and menu settings Window Display Nav Display WIDE ZOOM ON OFF VRM EBL CURSOR NM R NM R VRM EBL CURSOR NM R...

Page 20: ...area for the zoom picture 1 Press the DISP MODE key to select the window display The area selector a solid circle appears 2 Use the omnipad to place the area selector on the area to zoom Note When yo...

Page 21: ...intained at the 0 degree position while the heading line moves in accordance with ship s yawing and course change This mode is useful to avoid smearing of picture during course change WPT UP waypoint...

Page 22: ...LARM OUT ALARM Guard zone Figure 2 14 In and out alarms Setting the guard zone 1 Mentally create the guard zone you want to display See Figure 2 15 1 2 Operate the omnipad to set cursor on top bottom...

Page 23: ...Drag cursor here Figure 2 15 How to set a guard zone 2 17 Suppressing Radar Interference Radar interference may occur when near another shipborne radar operating in the same frequency band as your ra...

Page 24: ...ress the omnipad at 6 o clock to select P L IR NR Radar Mode and press the ENT key 3 Press the omnipad at 6 o clock to select Pulselength 4 Press the omnipad at 3 o clock 9 o clock to select SHORT or...

Page 25: ...ezes The oldest portions of trails are erased so only the latest trail equal in length to the trail time selected is shown Then trails start extending again For example the one minute trail time is se...

Page 26: ...omnipad at 6 o clock to select Nav Data and press the ENT key NAV DATA MENU Select item and option by keys 1 Navigator 2 Nav Data Disp 3 Pos Disp Mode 4 Depth Unit 5 Temp Unit 6 STBY Display Press HM...

Page 27: ...echo stretch function Echo stretch OFF Echo stretch ON Distant echo Figure 2 21 Echo stretch Turning echo stretch on or off 1 Press the MENU key 2 Press the omnipad at 6 o clock to select P L IR NR Ra...

Page 28: ...by the MENU key 2 26 Watchman How watchman works The watchman function periodically transmits the radar for about one minute to check for targets in a guard zone If it finds change in the zone from t...

Page 29: ...the ENT key Current selection is underlined 5 Press the ENT key 6 Repeat steps 4 and 5 to disable or enable other ranges 7 When finished press the MENU key 2 29 Displaying Navigation Data During Stan...

Page 30: ...an be output to the navigator connected to this radar by pressing and holding down the HM OFF key 2 31 Displaying Cursor Position Range and Bearing to Cursor The cursor data indication at the bottom o...

Page 31: ...an upper layer of warm dry air over a surface layer of cold moist air Radar waves bend downward and thus increase the ranges at which targets may be detected Sub refraction Sub refraction is the reve...

Page 32: ...re less subject to changes in aspect These types of targets have three flat smooth surfaces mutually at right angles Some radar buoys are arranged this way so as to deliberately increase their detecti...

Page 33: ...breakwater A second a third or more echoes may be observed on the display at double triple or other multiples of the actual range of the target as shown in Figure 3 4 Multiple reflection echoes can b...

Page 34: ...nd their shapes may indicate they are not direct echoes Heading marker Indirect echo True echo Heading marker Indirect echo True echo Direct path Target Indirect path Obstruction mast funnel etc Anten...

Page 35: ...dditional 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 9500 MHz 920...

Page 36: ...to the minimum Care should be exercised as a wanted target in sea clutter may be obscured Note also that in clutter conditions the first few dots of the SART response may not be detectable irrespectiv...

Page 37: ...e same frequency as that of the triggering radar in which case it is superimposed on the ship s radar display automatically The racon signal appears on the PPI as a radial line originating at a point...

Page 38: ...rips and plugs in antenna unit LCD Display unit connectors Check point Check for corrorded or loosened nuts and bolts If necessary clean and repaint them thickly Replace them if heavily corroded Check...

Page 39: ...gain with FTC and STC off a key is pressed But the control panel does not light nothing appears on the display or display contrast is poor characters are distorted the antenna does not rotate charact...

Page 40: ...perating properly 4 To escape from the test press the MENU key The ROM and RAM are automatically checked If NG No Good appears to the right of ROM or RAM indication contact your dealer for advice NMEA...

Page 41: ...gth SHORT LONG 2 Int Reject OFF 1 2 3 3 Noise Reject OFF ON 4 Echo Stretch OFF ON 5 Radar Mode CU WPT UP 1 Navigator ALL GPS LC 2 Nav Data Disp OFF ON 3 Pos Disp Mode L L TD 4 Depth Unit M FA FT 5 Tem...

Page 42: ...Radiator Slotted wave guide array 2 Polarization Horizontal 3 Antenna Rotation Speed 24 rpm nominal 4 Radiator Length 100 cm 5 Horizontal Beamwidth 2 4 nominal 6 Vertical Beamwidth 25 nominal 7 Sidel...

Page 43: ...rval Display Mode HU Interference Rejection IR Variable Range Marker VRM Electronic Bearing Line EBL Stand by ST BY Guard Alarm G IN G OUT Echo Stretch ES Range and Bearing to Cursor Bearing or L L Po...

Page 44: ...to 70 C IEC 60945 Display Unit 15 C to 55 C 2 Relative Humidity 93 2 at 40 C 3 Waterproofing Scanner Unit IPX6 IEC 60529 Display Unit IPX5 4 Bearing Vibration IEC 60945 7 COATING COLOR 1 Display Unit...

Page 45: ...11 Display mode 2 10 E EBL 2 2 2 7 EBL reference 2 19 EBL key 2 1 2 7 ECHO key 2 1 2 4 ENT key 2 1 Echo stretch 2 18 Echo trail 2 16 F FTC 2 4 2 6 3 6 Fuse 4 2 G GUARD key 2 1 2 13 GAIN 2 4 3 6 Guard...

Page 46: ...ing 2 6 Selecting 2 3 Range resolution 3 2 S ST BY TX key 2 3 STC 2 4 Self test 4 3 Side lobe echoes 3 3 Sub refraction 3 1 Super refraction 3 1 System configuration v T Tone 2 3 TONE key 2 1 2 3 TRAI...

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