Furuno FAR-1416, Operator'S Manual

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1. OPERATIONAL OVERVIEW
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1.20.2 How to manually reduce rain clutter
The vertical beam width of the antenna is designed to see
surface targets even when the ship is rolling. However, by
this design the unit will also detect rain clutter (rain, snow, or
hail) in the same manner as normal targets.
The A/C RAIN control adjusts the receiver sensitivity as the
A/C SEA control does but rather in a longer time period (lon-
ger range). The higher the setting the greater the anti-clutter
effect. When echoes from precipitation mask solid targets,
adjust the A/C RAIN control to split up these unwanted
echoes into a speckled pattern, making recognition of solid
targets easier. Be careful remove all rain clutter, because you
can erase weak echoes. Further, the possibility of losing
weak echoes is greater when you use both A/C RAIN and A/
C SEA to reduce clutter.
How to fine-tune sea clutter reduction from the control unit (RCU-029)
Rotate the AC/RAIN knob ( F2 ). Rotate anticlockwise to decrease the AC/SEA, or
clockwise to increase the A/C SEA.
How to fine-tune sea clutter reduction from the on-screen box
1. Select the [RAIN] indication at the top-right of the screen, then press the left but-
ton to select [RAIN(M)].
2. While observing the A/C RAIN level indicator, rotate the scrollwheel downward
to increase the A/C SEA or upward to decrease it. 100 levels (0 to 100) are avail-
able.
Note: The detection range is reduced when the RAIN is used to show targets in rain.
Generally, the amount of rain, TX pulse length and TX frequency are factors in deter-
mining how the detection range is affected. The figure below illustrates this.
How to interpret the graph
Using the graph below as an example, a radar target originally detected on the 8 NM
range can only be detected in rain at the ranges shown below:
Rain clutter at
screen center
A/C RAIN control
adjusted;
rain clutter reduced
Place arrow inside window
to adjust A/C RAIN.
A/C RAIN adjustment method
(RAIN AUTO or RAIN MAN)
RAIN MAN
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