That equipment used to show radar information is called, a display, or an indicator. Figure 15 1 is a generic representation of an FAA planned-position-indicator (ppi) display of the type to be found at an ASR facility. Formal academic literature may refer to this as a ?? (rho-theta) display, where ? denotes the radius of a circle, and ?, the angle of the radius; these dimensions are, of course, the range and azimuth, Shown on the illustrated display are range marks, a video map, normal video, and ARTS alphanumerics. The basic principles of ppi displays were addressed in Chapter 4. This chapter will deal principally with the ppi display, and associated equipment; however, some mention of other types is worthwhile, if only to provide the reader with some ability to participate in intelligent discussions with those in branches of the radar field other than air traffic control.

Figure 15 1: An FAA PPI Display.

Many attribute microwave technology as the most important development in radar; others assign the importance to sensitive receivers. However, no part of radar technology could have been of any use without the cathode ray tube (crt), the means of displaying the received echoes. The history of this device began substantially earlier than one might expect; it is traceable to an English scientist, Sir William Crookes, in 1875, Crookes built a device in which a beam was made to pass through a space, under the...