Section 7 True and False Echoes on Display  7-6 
 
 
 
 
 
 
 
 
 
 
 
 
 
Under rain, the targets that enter within sea clutter may be more difficult to detect. 
 
 
7.3.3  Coping with sea clutter and rain/snow clutter 
Under the conditions of rough ocean due to bad weather, the use of S band radar is effective because 
of its comparatively low influence from sea clutter and low attenuation against raindrops. When an X 
band radar is used, the use of short pulse is effective by reducing the applied pulse width since a 
reduction of the pulse width reduces the influence of interfering waves and also increases the effect of 
interfering wave rejection function. The effect of interfering wave control can be enhanced further by 
setting various items of Radar signal information.   
By using the observation scene selection function, the optimum setting values can also be retrieved 
according to various conditions such as weather (the setting value for Storm or Rain is recommended 
for stormy weather).   
For the description  of the observation  scene button, refer to "5.3.7 Adjusting  to optimal images 
(Selection of observation scenes)". While these settings are effective, targets, particularly, those that 
move at high speed may not be recognised visually. 
   
Detection range while it is not raining (NM) 
Detection range while it is raining (NM) 
Precipitation of 16mm/hr Pulse length 0.05µs 
Precipitation of 4mm/hr Pulse length 0.05µs 
Precipitation of 16mm/hr Pulse length 0.8µs 
Precipitation of 4mm/hr Pulse length 0.8µs 
 
Decreased Target Detection Range by 
X Band Radar due to Precipitation
   
Detection range while it is not raining (NM) 
Precipitation of 16mm/hr Pulse length 0.05µs 
Precipitation of 4mm/hr Pulse length 0.05µs 
Precipitation of 16mm/hr Pulse length 
0.8µs 
Precipitation of 4mm/hr Pulse length 
0.8µs 
Decreased Target Detection Range b
y S Band Radar due to Precipitation 
Detection range while it is raining (NM)