Furuno FAR-2107(-BB) - Manual (Page 52)

1. RADAR OPERATION
1-30
Note: The detection range is reduced when the A/C RAIN is used to show
targets in rain. Generally, the amount of rain, TX pulse length and TX
frequency are factors in determining how the detection range is affected.
The figures shown below illustrate this occurrence.
16 mm/h rain - short pulse
4 mm/h rain - short pulse
16 mm/h rain - long pulse
4 mm/h rain - long pulse
Reduction of rain to first detection due to rain at S-band
Reduction of rain to first detection due to rain at X-band
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reproduce Information from its International Standard IEC 62388 ed.1.0 (2007). All such extracts
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IEC 62388 ed.1.0 Copyright © 2007 IEC Geneva, Switzerland.www.iec.ch
Reduction of Range of First Detection (NM)
Original Range of First Detection (NM)
14
16
12
10
8
6
4
2
0
0 2 4 6 8 10 12 14 16
16
12
10
8
6
4
2
0
14
0 2 4 6 8 10 12 14 16
Original Range of First Detection (NM)
Reduction of Range of First Detection (NM)
16 mm/h rain - short pulse
4 mm/h rain - short pulse
16 mm/h rain - long pulse
4 mm/h rain - long pulse
16 mm/h rain - short pulse
4 mm/h rain - short pulse
16 mm/h rain - long pulse
4 mm/h rain - long pulse
4 mm/h rain (short pulse)
16 mm/h rain (short pulse)
16 mm/h rain (long pulse)
4 mm/h rain (short pulse)
4 mm/h rain (short pulse)
4 mm/h rain (long pulse)
16 mm/h rain (short pulse)
16 mm/h rain (long pulse)
How to read the graph
Using the X-band graph as an example, here is how to read the graphs.
A radar target detected in rain on the 8 nm range scale can only be detected at
the ranges shown below:
4 mm/h rain (short pulse):
approx 7.5 nm
16 mm/h rain (short pulse): approx 5.6 nm
4 mm/h rain (long pulse):
approx 2.6 nm
16 mm/h rain (long pulse): approx 0.9 nm