McDonnell Douglas A-4E Skyhawk, Manual

Page: 35 / 99

7. Sensors
AN/APG-53A Radar System
The search mode presentation displays range
versus azimuth. Either 0- to 20-mile range or 0- to
40-mile range in nautical miles may be selected.
The range in use is shown by a flag-type marker in
the plan-view aircraft at the bottom of the scope.
The indicator face is divided by horizontal lines,
each representing one-fifth of the total range.
This gives a calibration line every 8 miles for LONG
and 4 miles for SHORT.
In SRCH, the radar antenna is programmed to
sweep 60 degrees in azimuth using a 5 degree
cone of radiation at the elevation angle (antenna
tilt) selected by the pilot. Vertical marks on the zero
elevation line of the reticle show the approximate
bearing to any point on the display. The marks
represent 6, 18, and 30 degrees each side of
center. The antenna elevation is set by the pilot and
may be varied from 10 degrees above to 15
degrees below the flight path (angle-of-attack
switch ON).