What are unwanted echoes and signals appear on Radar screen?

Written by Amit Sharma

The navigator must be able to recognize various abnormal echoes and effects on the radarscope so as not to be confused by their presence.


Indirect or false echoes are caused by reflection of the main lobe of the radar beam off ship’s structures such as stacks and kingposts. When such reflection does occur, the echo will return from a legitimate radar contact to the antenna by the same indirect path. Consequently, the echo will appear on the PPI at the bearing of the reflecting surface. This indirect echo will appear on the PPI at the same range as the direct echo received , assuming that the additional distance by the indirect path is negligible.

Characteristics by which indirect echoes may be recognized are summarized  as  follows:

About the author

Amit Sharma

Graduated from M.E.R.I. Mumbai (Mumbai University), After a brief sailing founded this website with the idea to bring the maritime education online which must be free and available for all at all times and to find basic solutions that are of extreme importance to a seafarer by our innovative ideas.