Figure 5-20 -- Improved Precision Approach RADAR Trainer (IPART).
Special Circuits, Equipment, and Tolerances
A basic PPI display shows all types of RADAR echoes--both fixed and moving targets.
Ground targets normally displayed as strong echoes and weather echoes could mask
echoes from aircraft flying over these areas. Any echo that is undesirable or that
prevents the controller from observing aircraft is called clutter. Sometimes it is called
noise because it is analogous to static of a radio receiver. When it comes from the
ground or sea, it may be called ground return or sea return respectively. Special circuits
have been added to the basic RADAR components to eliminate or reduce clutter.
Special Circuits
Many factors affect RADAR control. As an example, the amount of reflective surface of
an aircraft determines the size of RADAR return. Remember there are limitations to
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