Furuno FAR-1513 Operator's Manual page 38

1. OPERATIONAL OVERVIEW
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 MAN].
2. While observing the A/C RAIN level indicator, rotate the ADJUST knob clockwise
to increase the A/C SEA or counter-clockwise to decrease it. 100 levels (0-100)
are available.
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:
16
16 mm/h rain - short pulse
4 mm/h rain - short pulse
14
16 mm/h rain - long pulse
4 mm/h rain - long pulse
12
10
8
6
4
2
0
0 2
Reduction of rain to first detection due to rain at X-band
The author thanks the International Electrotechnical Commission (IEC) for permission to reproduce Information from its Interantional
Standard IEC 62388 ed.1.0 (2007). All such extracts are copyright of IEC, Geneva, Switzerland. All rights reserved. Further
information on the IEC is available from www.iec.ch. IEC has no responsibility for the placement and context in which the extracts
and contents are reproduced by the author, or is IC in any way responsible for the other content or accuracy therein.
Accordingly, the short pulse may be preferable in rain on ranges less than 10 NM.
1-22
Level bar
4 6 8
Original range of first detection (NM)
Place arrow inside window
to adjust A/C RAIN.
10 12 14
4 mm/h rain (short pulse)
4 mm/h rain (long pulse)
16 mm/h rain (short pulse)
16 mm/h rain (long pulse)
16