2.21 Echo Trails

You can show the trails of targets in after- glow. 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 sec- onds to select a different trail time, among 15 sec, 30 sec, 1 min, 3min, 6 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

 

(requires gyro)

Figure 2-17 Appearance of echo trails

Fixed time trails

When the elapsed time clock counts up to the trail time selected, the elapsed time dis- play 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)Select Backlight/Brilliance and press the [ENT] key.

3)Select Echo Trails.

4)Select brilliance.

5)Press the [ENT] key followed by the [MENU] key.

Canceling echo trails

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

2.22The Navigation Data Display

Navigation data can be displayed at the screen bottom if this radar receives naviga- tion input in NMEA 0183 format. Naviga- tion data includes

position in latitude and longitude or Lo- ran-C time differences (TDs)

bearing and range to a waypoint selected on the navigator

cross track error (XTE—the amount in nautical miles and the direction the ves- sel if off course)

depth

speed.

If the navigation data include the destina- tion data, waypoint position is denoted on the radar display by a dashed ring.

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Furuno 821, 841 manual Echo Trails, Navigation Data Display