Antenna Control (Hand Control)

Mode Switch INDICATOR DISPLAYS The mode switch is practically self-explanatory. In the trainer, this switch sets up one of the basic operating modes available, such as search, bomb director, or fire control. Receiver Gain Control The receiver gain control is one of the most important controls available to the operator, whether the pilot in the aircraft or an operator on a trainer. This control, if not properly adjusted, will prevent the entire system from operating at peak performance. Some radar systems include a built-in test function, which provides a reasonable check of the adjustment of the receiver gain control. This control is normally adjusted for best definition of the weakest target available. There is only one acceptable method for adjusting this control to obtain peak detection, which provides maximum range. In each particular radar, this method is part of the minimum performance test. Antenna Control (Hand Control) The hand control of an actual radar installation allows the operator to select manual search operation and selection of targets. Through the use of this control, the operator may command the radar to acquire and/or release the target. The 11D13A has two controls, one for azimuth and one for range. During automatic search, these controls have two functions---(1) to position the antenna in elevation and azimuth, and (2) to select the area to be searched in relation to the horizon. You can see that these controls and the receiver gain control are very important because they will affect target detection performance. The hand controls have complete control of the antenna during manual search, and, in addition, also control the acquisition symbol to acquire the target. Auxiliary Controls Through the use of a scan switch in an operational radar, the operator may select either full azimuth or sector scan. The trainer, likewise, incorporates a scan switch that may be used to select the type of scan desired. In the trainer, the selections are automatic sweep at a 6-RPM rate, variable sweep from zero to 6 RPM manually controlled, or sector scan. A description of the indicator displays (PPI or B-scope) in the three basic modes of operation and the submodes of fire control is given in the following paragraphs. The indicators are used to monitor system performance during simulated operation in all weather conditions. Basic Search In the basic search mode, information is displayed on the PPI only. As shown in figure 3-10, the PPI scan presentation may be a maplike picture of the earth’s surface being seamed. The range sweep line rotates in synchronization with the antenna through a full 360-degree cycle. Targets appear on the face of the CRT as an intensified light spot. The range of the target is indicated by its position on the radius of the range sweep line, and target azimuth position is indicated by the angle of the sweep line at the time the target is painted. The top of the scope is 0 degree, and may indicate dead ahead. If 1,000-yard marks are selected, the two range marks shown in the figure are 1,000 yards apart. The first range mark, which starts from the center of the scope and moves outward toward the edge of the scope face, indicates targets from zero to 1,000 yards. There are two targets shown in figure 3-10 that are between the 1,000- and 2,000-yard marks. Other targets are shown at greater ranges and at different Figure 3-10.-PPI scan presentation basic search. 3-11