Furuno 821, 841 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 First Edition AUG Useable Environment Safety ArrangementsElectrical Shock Hazard Ground both the Display Unit and the Antenna UnitTable of Contents Foreword FeaturesDisplay Unit SPECIFICATIONS- ModelAntenna Unit Transceiver Module contained in radomeVibration Power supply & power consumptionProtection features Warm-up time Modulator switching methodReceiver front end MIC Michoeave IC Bandwidth 7 MHz Duplexer Ambiont temperatureInterface Nmea Model 821/841 Page Model 821/841 ConfigurationPrinciple of Operation How radar works Control Description OperationTurning the Radar On Off Display Indications and MarkersSelecting the Range Adjusting LCD Backlighting and Display ToneAdjusting Control Panel Brilliance TransmittingSTC MAN Auto Adjusting GAIN, STC, A/C Rain and FTCHow to tune manually Tuning the ReceiverAdjusting A/C Rain Adjusting FTCMeasuring the Bearing Measuring the RangeTarget on collision course with your vessel? Menu OperationMenu description 11 Display modes Selecting the Display ModeWindow Display Selecting the Presentation ModeCU course-up WPT-UP waypoint-up Guard AlarmGuard Suppressing Radar InterferenceOff Centering the Display Suppressing Noise InterferenceSelecting Pulselength Navigation Data Display Echo TrailsPress the Menu key Select Nav Data and press the ENT key Echo Stretch magnifying long range echoesSelecting Bearing Reference Selecting Unit of Measurement for RangeWatchman Deselecting Ranges Erasing the Heading MarkerDisplaying Navigation Data During Stand-by Outputting Cursor Position to Navigator Visual Alarm IndicationsDisplaying Cursor Position, Range and Bearing to Cursor Super-refraction Interpreting the DisplayRadar Wave and Radar Horizon Target Properties and Radar Wave ReflectionRange Resolution Bearing ResolutionFalse Echoes Multiple echoes Blind and shadow sectors Nautical Chart and Radar PictureTroubleshooting procedure Maintenance & TroubleshootingSafety Information Forming any maintenance orReplacing the Fuse Preventative MaintenanceTroubleshooting table TroubleshootingSelf Test Self TestAntenna Unit Installation InstallationMounting platform Removing packing materialsVent tube How to fasten the radome base To the mounting platform Ships bow Removing packing materials 10 Antenna unit Model 841, inside view, shield cover removed 12 Optional mounting bracket installation for sailboat Display Unit Installation 13 How to mount the display unit 14 Display unit, rear view Procedure Option connectorInstallation Check List Displaying the Installation Menus Initial Adjustment of PictureRelative Bearing Alignment Entering Initial SettingsSweep Timing Closing the Installation MenusSignal cable connection Page Page Page Page Page Page Page