Furuno 1932 MARK-2 manual Selecting the Range, Adjusting Picture Brilliance

Note1: Availability of a particular display item depends on incoming data.

Note2: When Range to Waypoint reaches 0.1 nm, the WPT marker jumps to dead ahead even though a difference may exist between heading and BRG to WPT.

Note3: When cross track error exceeds 1 nm on either side, the XTE mark starts blinking.

2.5 Selecting the Range

The range selected automatically determines the range ring interval, the number of range rings, pulselength and pulse repetition rate, for optimal 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 cor- ner of the display.

To select a range;

Press the [- RANGE +] key . The range and range ring interval appear at the top left cor- ner of the display.

Tips for selecting the range

¡When navigating in or around crowded harbors, select a short range to watch for possible 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.

2.6 Adjusting Picture Brilliance

The [BRILL] key adjusts the brilliance of the radar picture in sixteen levels. The current level momentarily appears on the screen whenever the [BRILL] key is pressed.

2.7Adjusting 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 back- ground noise is just visible on the screen. If you set up for too little sensitivity, weak ech- oes may be missed. On the other hand ex- cessive 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 back- ground noise is just visible on the screen.

2.8Adjusting the A/C SEA Control

(reducing sea clutter)

Echoes from waves can be troublesome, cov- ering the central part of the display with ran- dom signals known as “sea clutter .” The higher the waves, and the higher the scan- ner above the water , the further the clutter will extend. Sea clutter appears on the dis- play as many small echoes which might af- fect radar performance. (See the left-hand figure in 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 amplifi- cation of echoes at short ranges (where clut- ter is the greatest) and progressively increases amplification as the range in- creases, so amplification will be normal at those ranges where there is no sea clutter.

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