Furuno FAR-21 7-BB Series, Operator'S Manual

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1. RADAR OPERATION
1-47
1.28.4 Saving, copying target trails
By turning on the functions TRAIL RESTART and TRAIL COPY, you may
continue painting target trails whenever the range scale is changed. The amount
of range change determines how the radar paints trails. See the table below for
details. Note however that if the previous range is restored within 10 seconds
and the amount of range change is within 1/3, trails continue as before.
If trails become difficult to view trails, you may delete them. For details, see
paragraph 1.28.9.
Amount of range change How trails are processed
Large (ex. 3 nm → 12 nm) Trails continue on targets which were within the
previous range scale; trails are not initiated for
targets which were not within the previous range.
Within 1/3 of previous range
(ex. 3 nm
→ 1.5 nm)
Trails continue on targets which were in the
previous range scale.
Within 1/4 of previous range
(ex. 3 nm
→ 0.75 nm)
Trails are restarted.
(a) Previous range
(b) New range
No trail generated
for target not within
previous range
1. Roll the trackball to place the arrow on the TRAIL MODE box at the bottom
right corner of the screen.
2. Push the right button to display the TRAIL menu.
3. Roll the wheel to choose 5 TRAIL RESTART and then push the wheel or the
left button.
4. Roll the wheel to choose ON or OFF as appropriate and then push the wheel
or the left button.
ON: Trails start extending on the newly selected range.
OFF: Trails extend only on the range where they were initiated.
5. Roll the wheel to choose 6 TRAIL COPY and then push the wheel or the left
button.
6. Roll the wheel to choose ON or OFF as appropriate and then push the wheel
or the left button.
7. Push the right button to close the menu.