A display used with a radar set, the aerial of which is continuously rotating.
The screen, of the long persistence type, is excited only while the beam of the aerial system is within a narrow sector which can be selected at will.
Note: A sector display can be used in conjunction with either an A-scan display or a P.P.I.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM