PERFORMANCE MONITORING

In mode 4, the reply video pulse is checked by the RT for proper pulse spacing and width. A single reply pulse is forwarded to the computer for further decoding. The mode 4 decoded video is applied to the synchronizer, where two pulses spaced 12 or 28 microseconds apart are generated for display by the radar set. PERFORMANCE MONITORING.— The IFF interrogator set includes performance monitoring circuits in each of the boxes. When a fault is detected, a signal is sent through the synchronizer to the control box. This signal will cause a FAULT light to illuminate instead of the normal CHAL light. When the TEST-CHAL CC switch is set to TEST, the IFF interrogator and the IFF transponder are linked together. This is done by disabling the normal suppression, ISLS, and RSLS operations. The trigger timing is also modified to place the zero-range replies at approximately 4 nautical miles on the radar display. In this configuration, the two sets are checked by each other for proper performance. REVIEW QUESTIONS Q1. What type of search radar is the APS-115B? Q2. What is the tilt range of the AS-2146/ APS-115? Q3. Q4. Q5. Q6. Q7. Q8. Q9. Q10. Q11. Q12. Q13. Q14. Which control switch on the C-7511A/ APS-115 is used to select the antenna sector mode? How many functional subsections are in a RT-889/APS-115? What is the scan rate of the AS-2146/APS-115 in the long pulse mode of operation? How many operating modes are available on the 11D13A? What is the minimum range in fire control operations? In the fire control (automatic search) mode, what name is given to the 1/4-inch scan line? At what closing rate will lock on be lost in the fire control (automatic track) mode? What indication on the scope indicates breakaway? What are the five modes used in IFF opera- tions? What antenna(s) is/are used by the IFF transponder system? The APX-76 interrogator uses what carrier frequency for transmission? What light illuminates when one of the APX-76 components fail? 3-23