
THE RADAR SYSTEM - OPERATIONAL PRINCIPLES
55
number of traces for any set of values can be obtained by
using the relationship set out in Section 2.4.4 for cal-
culating the number of strikes per point target and sub-
stituting the angular width of the heading marker for
that of the horizontal beam width.
A number of methods have been used to operate the
heading marker switch. One such method uses a small
cam on a rotating part of the aerial unit to depress the
switch as it goes past once during each revolution of the
aerial. In all systems it is possible to adjust the point at
which contact is made over a range of azimuth of about
5° to 10° s ...