154.3.6. To remove the interference of Sea Level Wave caused by the Sea Wave(1) When the wave becomes high due to heavy wind, the ECHO(Sea Clutter) due to the wave is displayed onPPI screen, then it will be difficult to detect the image of the target.(2) Turn (Sea Clutter) to the right to remove the echo image by wave.The status that shows Sea Level Relection The status that shows Sea Level Reflection isis strong due to Wave. being suppressed. (The Target is also suppressed)4.3.7. To operate the alert function Set the guide zone in order to use the alert. Guard Zone means [Zone] to be set on PPI screen.(1) Guard Zone SettingIn bottom of the screen, the functionof GUARD:RingFan is shown andin bottom-right of the screen, CRSData is shown with the distance &bearing of the cursor based on theposition of own ship.Press to select Ring or Fanfunction.a) How to set up Alert Zone based on the positionof own ship as selecting Ring function.The message of Press ENT to setis shown onto a screen with a red-ring mark.Adjust the Alert Zone controlling therea-ring.The alert zone is set up and thesound is ringing, if it has a target inthe zone.b) By selecting Fan function, how to set up aspecific zone onto a heading of PPI screen.Put the cursor onto top-left in aspecific zone to be controlled byusing a bearing button.Press ENT to set is shown in ascreen.Move the cursor to bottom-right in aspecific zone to mark the fanning-shape.The alert zone is set up and thesound is ringing, if it has a target inthe zone.ATTENTION※ If you set the removal function of Sea Level Wave up to removal of all Sea LevelReflection at short distance, it causes intereference in detecting images due to thetarget of vessel and dangerous things as well as the wave images beingsuppressed.※ When you use the removal function of Sea Level Wave, you make sure it should bethe optimistic set of suppression.