Figure 141.
Broad and Narrow Horizontal Beams.
b. Now notice in Part B of Figure 141 how a narrow horizontal beam
gives more accurate azimuth information. The indicator tells the operator
that the bomber is exactly 40 degrees east. Fighters directed to intercept
an enemy jet using information from this set can head straight toward the
target.
c. Remember, then, that a radar set must have a narrow horizontal beam
to give accurate azimuth information.
18. A narrow vertical beam gives accurate height information.
a. To provide accurate elevation information, the radar set must have a
narrow vertical beam. You can see the reason by comparing the two height-
finding sets shown in Figure 142. Notice that the set in Part A of Figure
142 sends out a broad vertical beam. The beam is so broad that even when
the antenna is pointed at an angle of 40 degrees, it picks up a plane that
is at an angle of 15 degrees.
The operator of the set knows, of course,
that the enemy plane is there, but is not able to determine the exact
height.
If this information is used to aim and fire antiaircraft guns
automatically, the guns will miss the target because of the inaccurate
information.
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