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?
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