Selecting Unit Of Measurement For Range; Selecting Bearing Reference; Watchman - Furuno 821 Operator's Manual

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.
2.24 Selecting 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.
2.25 Selecting 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.
18
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.
St-by
Tx
1 min
5, 10 or
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
Tx
St-by
1 min 5, 10 or
20 min