AF 160, 162-171, 183, 184 CONFIG 4 01 Page 23 Sep 25/9434-43-00
(f)
AF 183, 184; GND CLTR SPRS in ON - the GND CLTR SPRS switch enables the ground clutter suppression (GCS) circuitry. The switch is spring loaded to the OFF position. RF return signals that are determined to have a high probability of originating from the ground are automatically removed from the display. Weak weather targets may be removed as well. The GCS may be used in all ranges.
(g)
AF 183, 184; GND SPRS in ON - the GND SPRS switch enables the ground clutter suppression (GCS) circuitry. The switch is spring-loaded to the OFF position. RF return signals that are determined to have a high probability of originating from the ground are automatically removed from the display. Weak weather targets may be removed as well. The GCS may be used in all ranges. 1) TILT control - Tilts the antenna radiator up or down a
maximum of 15 degrees from the zero reference position. Antenna tilt in + or - degrees is displayed in the lower RH corner of the weather radar indicators.
2) GAIN control - R/T gain is manually controlled in the WX, WX+T and MAP modes when the GAIN control is rotated out of the CAL (calibrate) position. Gain decreases with CCW rotation of the GAIN control. When the GAIN control is in the CAL position no gain message is present in slot 10. The first gain message CCW of CAL is MAX, then -1 thru -7 to MIN in the most CCW position.
(12) Antenna Functions (Fig. 3)
(a)
The Radar Antenna is a split-axis type mount, having its elevation axis mounted on the scan axis. It is stabilized by a microprocessor-controlled digital servo loop located in the receiver/transmitter unit. The antenna can be manually tilted | 15 degrees from the horizontal (zero-degrees) and is stabilized over a combined tilt, pitch, and roll input of | 45 degrees.
(b)
The antenna unit consists of the antenna pedestal and the antenna flat plate radiator. The pedestal itself contains two independent power supplies, motor drivers, receiver/monitor drivers, incremental and zero monitors to provide command signals to the scan and elevation stepper motors.
(c)
The flat plate radiator develops the required pencil beam radiation pattern by means of phase reinforcement/cancellation of energy from adjacent slots in the planar array.
EFFECTIVITY
AF 160, 162-171, 183, 184 CONFIG 4 01 Page 24 Sep 25/9434-43-00
(d)
The motor driver provides an interface with the power supply to pass the binary encoded scan and elevation drive signals from the R/T to the receiver/monitor driver, and the scan and elevation monitor signals from the receiver/monitor driver to the system R/T. The receiver/monitor driver buffers and translates the binary encoded scan and elevation drive signals to provide motor positioning control signals to the motor driver. It also buffers the incremental and zero monitor signals and provides a binary encoded output to the R/T for interpretation. When commanded by the receiver/monitor driver, the motor driver provides drive voltages to incrementally rotate the scan and elevation stepper motors to move the antenna | 90 degrees in scan and | 40 degrees in elevation in 0.25-degree steps.
(e)
Incremental monitors track the motor shaft rotation of the scan and elevation stepper motors from a zero reference point to provide constant monitoring for use by the selected receiver/transmitter.
(f)
Zero monitors provide a reference synchronizing point for the scan and elevation stepper motors from which incremental changes in antenna position can be measured by the incremental monitors.
(g)
Scan and elevation toggle switches provide a manual means of disabling the input power to the scan and elevation stepper motors. When the pedestal cover is closed, the switches are tripped to ON position by the cover. This prevents the switches from being inadvertently left in OFF position and disabling the antenna drive.
(13) Receiver/Transmitter Functions (Fig. 3)
(a)
The R/T unit is a lightweight airborne unit consisting of transmitter, receiver, video processing circuitry, a central processing unit (CPU), input/output circuits, system monitoring circuitry, and power supply.
(b)
The source of the RF transmission is in the R/T unit driver, where a signal is generated and applied to the power amplifier. In the power amplifier, the signal is amplified and split into two separate signals. The multiplier frequency multiplies the signals from the power amplifier in two stages and recombines them to obtain the 125-watt transmitter output signal.
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本文链接地址：747飞机维护手册AMM CHAPTER 34 - NAVIGATION 第34章导航3(108)
