
264
RADAR AND ARPA MANUAL
6 Use the most open scale appropriate.
7 When it is not necessary to display the rings, good
practice dictates that they should be switched off in
order to prolong the life of the phosphor area on
which they paint (see Section 2.6.1.2).
6.9.9 Bearing accuracy
As stated in Section 6.9.3, the IMO Performance Stan-
dards require that the means provided for measuring
bearings should enable the bearing of a target whose
echo appears at the edge of the display to be measured
with an accuracy of ± 1° or better.
It is essential to appreciate that the permitted error of
±1° refers only to the measurement of the angle (whose ...