Furuno FR-7252 Selecting the Range, Adjusting Picture Brilliance, Adjusting Receiver Sensitivity

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Note 1:Availability of a particular display item depends on incoming data.

Note 2:When Range to Waypoint reaches 0.1 nm, 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.

2.6 Selecting the Range

The range selected automatically determines the range ring interval, the number of range rings, pulselength and pulse repetition rate, for opti- mal detection capability in short to long ranges.

You can select which ranges and pulselength (for 1.5 and 3 mile ranges) to use through the menu. The range, range ring interval and pulselength appear at the top left-hand 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

ÁWhen navigating in or around crowded har- bors, select a short range to watch for pos- sible collision situations.

ÁIf 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 sixteen levels.

Press the [BRILL] key to set the brilliance level. The current level momentarily appears on the screen.

2.8 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 tar- gets may be missed because of the poor con- trast between desired echoes and the background noise on the display.

To adjust receiver sensitivity, transmit on long range, and adjust the [GAIN] control so back- ground noise is just visible on the screen.

2.9Adjusting the A/C SEA Control (reducing sea clutter)

Echoes from waves can be troublesome, cover- ing the central part of the display with random signals known as “sea clutter”. The higher the waves, and the higher the antenna above the wa- ter, the further the clutter will extend. Sea clut- ter appears on the display as many small echoes which might affect radar performance. (See the left-hand figure in Figure 2-4.) When sea clut- ter masks the picture, adjust the A/C SEA con- trol to reduce the clutter.

How the A/C SEA control works

The [A/C SEA] control reduces the amplifica- tion of echoes at short ranges (where clutter is the greatest) and progressively increases am- plification as the range increases, so amplifica- tion will be normal at those ranges where there is no sea clutter.

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Contents Marine Radar 00080819803 Safety Instructions Use the proper fuse Compliance with R&TTE Directive 1999/5/EC Sart Search and Rescue Transponder IiiSummary to detect Sart response Features ForewordTable of Contents Menu Tree ViiiSystem Configuration This page is intentionally left blank How Radar Determines Bearing What is Radar?How Radar Determines Range Radar DisplayHow radar works Basic Operation Control DescriptionDisplay Indications and Markers Turning the Radar On/Off Stand-byTransmitting Adjusting Picture Brilliance Adjusting Receiver SensitivitySelecting the Range Adjusting A/C Rain Adjusting the A/C Rain Control Reducing rain clutterAdjusting the A/C SEA control Tip for adjusting the A/C SEASelecting the Presentation Mode Erasing the Heading Marker, North MarkerMeasuring the Range Measuring the BearingPredicting collision course Using the Offset EBLTips for measuring bearing Measuring range and bearing between two targetsZoom Cancelling zoomCancelling shifted picture Shifting off centering the PictureThis page is intentionally left blank Index Lines Adjusting the index lines intervalBasic Menu Operation Turning the index lines on/offSelecting Pulsewidth Suppressing Radar InterferenceDisplaying Navigation Data To turn navigation data on or offGuard Alarm Echo TrailCancelling the guard zone and alarm Setting a guard zoneSilencing the audible alarm PreparationHow watchman works Cancelling watchmanWatchman Turning on watchmanOther Menu Description DescriptionFunction Keys Tuning the ReceiverAdjusting Brilliance of Markers Suppressing Second-Trace EchoesMultiple Echoes Side-lobe EchoesIndirect Echoes Blind and Shadow SectorsMaintenance & Troubleshooting Troubleshooting Page This page is intentionally left blank ARP-10 Option Keys Used for Auto Plotter Principal specificationsGeneral ARP-10 Menu operationActivating the Auto Plotter ARP menuAutomatic Acquisition Setting auto acquisition areaManual Acquisition Deactivating the auto plotterIndividual targets Terminating Tracking of TargetsDisplaying Target Data All targetsVector length Mode and Length of VectorsTrue or relative vector Past position displaySpecifications of Marine Radar FR-7062/7112/7252Display Unit Environmental Condition Dimensions and Mass Index Page