Furuno 841 MARK-2 manual Measuring the Range, Measuring the Bearing

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2.10 Measuring the Range

You can measure the range to a target three ways: by the range rings, by the cursor, and by the VRM (Variable Range Marker).

By range rings

Press the [RINGS] key to display the range rings. Count the number of rings between the center of the display and the target. Check the range ring interval (at the top left corner) and judge the distance of the echo from the inner edge of the nearest ring.

By cursor

Operate the cursor pad 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 dis- play.

By VRM

1)Press the [VRM] key to display the VRM.

2)Press the cursor pad to place the VRM on the inside edge of the target. (The cur- sor appears and is linked with the VRM, allowing you to measure both range and bearing to the target.)

3)Check the VRM readout at the bottom left-hand corner of the display to find the range to the target.

Note: The VRM is automatically anchored when no cursor pad key is operated within about 10 seconds.

To erase the VRM, press and hold down the [VRM] key for about three seconds.

1.5NM

0.5

Target

VRM

VRM

VRM

EBL

+ CURSOR

0.675NM 220.9°R

0.675NM 308.7°R

range

 

 

 

Figure 2-8 Measuring range by the VRM

2.11 Measuring the Bearing

There are two ways to measure the bearing to a target: by the cursor, and by the EBL (Electronic Bearing Line).

By cursor

Operate the cursor pad to bisect the target with the cursor intersection. The bearing to the target appears at the bottom right-hand corner of the display.

By EBL

1)Press the [EBL] key to display the EBL.

2)Press the cursor pad to bisect the target with the EBL. (The cursor appears and is linked with the EBL, allowing you to measure both bearing and range to the target.)

3)Check the EBL readout at the bottom left- hand corner of the display to find the bear- ing to the target.

Note: The EBL is automatically anchored when no cursor pad key is operated within about 10 seconds.

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Contents Marine Radar B . N o . O M E 3 4 4 4 Safety Instructions Do not open the equipment Stay away from transmitting antennaDo not disassemble or modify the equipment Do not operate the equipment with wet handsIii Use the correct fuseTable of Contents Features ForewordSpecifications Antenna UnitTransceiver Module contained in radome Display UnitInterface Nmea Installation Materials CP03-15xx Accessories FP03-05900Equipment List Complete SetOptional Equipment Configuration Model 841 MARK-2Principle of Operation How radar works Operation Control DescriptionDisplay Indications and Markers Turning the Radar On and Off5NM 675NM 220.9R 0.646NM 308.7RAdjusting LCD Backlighting and Display Tone Adjusting Control Panel BrillianceTransmitting Selecting the RangeSTC MAN Auto Adjusting GAIN, STC, A/C Rain and FTCGeneral procedure Tuning the Receiver Adjusting A/C RainAdjusting FTC How to tune manuallyMeasuring the Range Measuring the BearingSee the table on the next Menu OperationPress the Menu key to open the menu. The main menu appears Menu description Menu FunctionSelecting the Display Mode 11 Display modesSelecting the Presentation Mode Window DisplayCourse-up, you may select CU or WPT- UP, on the menu CU course-upGuard Alarm Setting the guard zoneSilencing the audible alarm WPT-UP waypoint-upCanceling the guard zone Suppressing Radar InterferenceSelecting Pulselength Suppressing Noise InterferenceOff Centering the Display Echo Trails Navigation Data DisplaySetting up the nav data display Echo Stretch magnifying long range echoesPress the Menu key Select Nav Data and press the ENT key Turning echo stretch on or offSelecting Unit of Measurement for Range Selecting Bearing ReferenceWatchman Turning on watchmanCanceling watchman Erasing the Heading MarkerDeselecting Ranges Displaying Navigation Data During Stand-byVisual Alarm Indications Error Visual alarmOutputting Cursor Position to Navigator Displaying Cursor Position, Range and Bearing to CursorInterpreting the Display Radar Wave and Radar HorizonTarget Properties and Radar Wave Reflection Super-refractionBearing Resolution Range ResolutionFalse Echoes Multiple echoesSide-lobe echoes Indirect echoesNautical Chart and Radar Picture Maintenance & Troubleshooting Safety InformationPeriod Check point Remarks Preventative MaintenanceReplacing the Fuse Troubleshooting But ThenSelf Test Self TestMounting Antenna Unit InstallationSiting, handling considerations Holes for antenna unit Parallel with the fore and aft lineDisplay Unit Installation Mounting considerationsMounting procedure Display unit is designed to be mounted on a tabletopSignal cable connection ConnectionsTo connect external equipment to the OP- Tion connector For E/SNavigation aid, video sounder connection Heading Sensor ConnectionInstallation Check List RadarFollow the procedure below to obtain proper radar picture Initial Adjustment of PictureDisplaying the Installation Menus Sweep Timing Entering Initial SettingsRelative Bearing Alignment Closing the Installation Menus Press the Menu key and turn off the powerPage Page Page Page Page Page