Raymarine Marine GPS System User Manual page 101

RayTech Navigator User's Guide
Controls to Adjust the Radar Picture
Control Option
GAIN GAIN
SEA
RAIN
FTC
SEA SEA
MULTI TUNE
TARGETS INT REJ
EXPANSION
WAKES
Identifying False Echo Returns
Not all echoes are direct returns to the radar antenna. Occasionally
signals appear at positions where there is no actual target. These are
called false echoes, and may be caused by side lobes, ghost images,
indirect echoes or multiple echoes.
This subsection briefly describes the echo patterns that can be
produced by false echoes and the likely cause. It should be noted that
the radar operator, through observation, practice, and experience, can
generally detect these conditions very quickly. These effects can
usually be minimized using the radar controls.
5-10
Function
Controls the strength of the target returns
Reduces sea returns
Reduces close rain or snow returns
Reduces distant rain or snow returns
Reduces sea returns
Fine tunes the receiver
Turns interference rejection on/off
Turns target expansion on/off
Turns wakes on/off and selects wakes length
Default Setting
AUTO
AUTO-HARBOR
OFF
OFF
AUTO-HARBOR
AUTO
ON
OFF
OFF