Furuno 821, 841 Selecting Unit of Measurement for Range, Selecting Bearing Reference, Watchman

5)Press the [ENT] key followed by the [MENU] key. ES appears at the top right side on the display when the echo stretch feature is on.

Note 1: This function magnifies not only tar- gets but also sea clutter and radar interference. For this reason be sure the controls for adjust- ment of sea clutter and radar interference are properly adjusted before activating the echo stretch.

Note 2: Echo stretch is inoperative on ranges from 0.25 to 0.75 nautical miles. ES appears in reverse video when you try to turn on the echo stretch in those ranges.

Note 3: When the echo stretch function is se- lected, Interference Rejection level #3, along with the Noise Rejection circuits, are automati- cally enabled. These can be turned off via menu selection if desired.

2.24Selecting Unit of Measurement for Range

The unit of measurement for the VRM and cursor can be nautical miles, kilometers, or statute miles. You may select unit desired as follows.

1)Press the [MENU] key.

2)Select Mode & Function and press the [ENT] key.

3)Select VRM Unit to nm, km, or sm.

4)Press [ENT] followed by [MENU] key.

2.25Selecting Bearing Reference

Bearing can be displayed relative to north (relative bearing) or relative to true north (true bearing) as follows. (True bearing re- quires heading sensor input.)

1)Press the [MENU] key.

2)Select Mode & Function and press the [ENT] key.

3)Select EBL Ref.

4)Select Rel(ative) or True.

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

2.26 Watchman

How watchman works

The watchman function periodically trans- mits the radar for about one minute to check for targets in a guard zone. If it finds change in the zone from the previous transmission it sounds the aural alarm, cancels the watch- man function, and transmits the radar con- tinuously. This feature is useful when you do not need the radar’s function continu- ously but want to be alerted to radar targets in a specific area.

Tx St-by Tx St-by

1 min 5, 10 or 1 min	5, 10 or
20 min	20 min

Watchman starts.

Figure 2-21 How watchman works

Turning on watchman

1)Create a guard zone (usually 360 degrees) with the guard alarm function.

2)Press the [MENU] key.

3)Select Mode & Function and press the [ENT] key.

4)Select Watchman.

5)Select watchman rest interval (amount of time until next rotation of antenna); 5 minutes, 10 minutes or 20 minutes.

6)Press the [ENT] key followed by the [MENU] key. Then, WATCHMAN ap- pears, and the radar transmits for one minute and then goes into stand-by.

Canceling watchman

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