Furuno FMD-1712 - Manual (Page 17)

9
1.20 Target Trails
Target trails are simulated afterglow of
target echoes that represent their
movements relative to own ship. This
feature is useful for monitoring targets’
movement.
3M TRAIL Trail time
(3 min)
Target trail
Figure 1-17 Target trails
Starting target trail
Press the [TRAIL] key to start the echo trail
function. "TRAIL" and the target trail time
appear at the top right-hand corner on the
screen, and then afterglow starts extending
from all targets. When the internal clock
counts up to the trail time selected, the
oldest portions of trails are erased so only
the latest trail, equal in length to the trail
time selected, is shown. For continuous
trails the maximum trail time is 99 minutes
and 59 seconds, at which point all trails are
erased and then restarted.
Canceling target trail
Press the [TRAIL] key to erase target trails
and target trail indications.
Trail time
1. Press the [MENU] key to open the
menu.
2. Select TRAIL TIME (on page 2 of the
menu).
3. Select target trail time desired;
continuous, 30 seconds, 1, 3 or 6 min as
appropriate.
4. Press the [MENU] key to register your
selection and close the menu.
Trail brilliance
1. Press the [MENU] key to open the
menu.
2. Select TRAIL BRILL (on page 2 of the
menu).
3. Select HIGH or LOW as appropriate.
4. Press the [MENU] key to register your
selection and close the menu.
1.21 Guard Alarm Zone
The guard alarm allows the operator to set
the desired range and bearing for a guard
zone. When ships, islands, landmasses, etc.
violate the guard zone the offending target
flashes and an aural alarm sounds to call
the operator’s attention. The alarm is
triggered against targets entering or exiting
the guard zone depending on guard zone
type as below.
* The alarm should not be relied upon as the
sole means for detecting possible collision
situations.
* STC, FTC and GAIN controls should be
properly adjusted to be sure the alarm
system does not overlook target echoes
.
CAUTION
How guard zone type is determined
After the guard zone is set, the radar starts
searching for targets inside the guard zone
for about 8 to 12 seconds. The results of the
search are shown at the top right-hand
corner of the display as “G (IN)” or “G
(OUT).”
G (IN): This is the inward guard alarm and it
means no target was found in the guard
zone. The guard alarm will be triggered by
targets entering the guard zone.
G (OUT): This is the outward guard alarm
and it means a target was found in the
guard zone. The guard alarm will be
triggered by targets exiting the guard zone.