DESCRIBE ANTENNA CIRCUITRY USING A SCHEMATIC DIAGRAM SOURCE PP

Question 1

Ant. Circuit Diagrams - Objective

Answer 1

Enabling Objective Given a knowledge test, DESCRIBE antenna circuitry using a schematic diagram, within specified time.

Question 2

Ant. Circuit Diagrams - A1 Modes of Op. - Azimuth & Tilt

Answer 2

Antenna (A1) Modes of Operation *Azimuth and Tilt Modes: oFour azimuth modes: STOP, SCAN, SECTOR, and AUTO oTwo tilt modes: MANUAL and AUTO

Question 3

Ant. Circuit Diagrams - A1 Modes of Op. - STOP

Answer 3

Antenna (A1) Modes of Operation *STOP: oAntenna is positioned to correspond with azimuth control (A5B2).

Question 4

Ant. Circuit Diagrams - A1 Modes of Op. - STOP - K2 & K4

Answer 4

Antenna (A1) Modes of Operation *STOP: oAntenna control switch energizes K2 and K4.

Question 5

Ant. Circuit Diagrams - A1 Modes of Op. - STOP - Error

Answer 5

Antenna (A1) Modes of Operation *STOP: oWhen A5B2 and A1B4 are not in correspondence, an azimuth error signal is produced. §Applied via K4 to amplifiers U3 and U7

Question 6

Ant. Circuit Diagrams - A1 Modes of Op. - STOP - Gen.

Answer 6

Antenna (A1) Modes of Operation *STOP: oGenerator §A rate generator (tachometer) driven by the motor §Develops a 400 Hz azimuth rate feedback

Question 7

Ant. Circuit Diagrams - A1 Modes of Op. - SECTOR - Feed

Answer 7

Antenna (A1) Modes of Operation *SECTOR: oAntenna reflector assembly rotates in reverse direction until opposite sector limit reached. oThe azimuth rate feedback is summed at U3 as in STOP and SCAN.

Question 7

Ant. Circuit Diagrams - A1 Modes of Op. - SECTOR - Rel.

Answer 7

Antenna (A1) Modes of Operation *SECTOR: oRelationship

Question 8

Ant. Circuit Diagrams - A1 Modes of Op. - SCAN (2)

Answer 8

Antenna (A1) Modes of Operation *SCAN, cont.: oAzimuth rate feedback signal developed and coupled to U3 via R5 and energized contacts of K2. oThe two voltages are algebraically summed at U3.

Question 8

Ant. Circuit Diagrams - A1 Modes of Op. - STOP - Gen. (2)

Answer 8

Antenna (A1) Modes of Operation *STOP: oGenerator, cont. §Azimuth rate feedback signal coupled to U3 via K2. §It is algebraically summed with error signal.

Question 8

Ant. Circuit Diagrams - A1 Modes of Op. - SCAN

Answer 8

Antenna (A1) Modes of Operation *SCAN: oAntenna reflector assembly driven clockwise (CW) at 6 rpm. §K3 energizes while K2 and K4 de-energize. §9 volts alternating current (VAC) from T1-3 applied to U3 and U7.

Question 9

Ant. Circuit Diagrams - A1 Modes of Op. - SCAN (3)

Answer 9

Antenna (A1) Modes of Operation *SCAN, cont.

Question 10

Ant. Circuit Diagrams - A1 Modes of Op. - SECTOR - Width

Answer 10

Antenna (A1) Modes of Operation *SECTOR: oWidth control §Amplitude of sector width reference signal set by sector width control. §Its phase shifts 180 degrees when K3 changes states.

Question 11

Ant. Circuit Diagrams - A1 Modes of Op. - SECTOR - Ref.

Answer 11

Antenna (A1) Modes of Operation *SECTOR: oReflector assembly §Algebraic sum equals 0 V. §U2A toggles. §Q1 changes state. §K3 changes state. §Direction of rotation reverses.

Question 12

Ant. Circuit Diagrams - A1 Modes of Op. - Antenna Tilt

Answer 12

Antenna (A1) Modes of Operation *Antenna Tilt Circuitry - Positions reflector between: o-15 and +10 degrees in MANUAL o-20 and +20 degrees in gyro stabilization or AUTO

Question 13

Ant. Circuit Diagrams - A1 Modes of Op. - Ant. Tilt - Man.

Answer 13

Antenna (A1) Modes of Operation *Antenna Tilt Circuitry: oMANUAL §Corresponds with setting of antenna tilt control (A5B1) and functions like azimuth drive assembly in STOP

Question 14

Ant. Circuit Diagrams - A1 Modes of Op. - Ant. Tilt - Man. (2)

Answer 14

Antenna (A1) Modes of Operation *Antenna Tilt Circuitry: oMANUAL, cont. §A5B1 is repositioned. §Tilt control transformer (A1B3) no longer in correspondence. §An error signal is produced.

A1B3 applied to amplifiers U4 & U6 via R31. vThis establishes volts per degree-of-tilt.

Question 15

Ant. Circuit Diagrams - A1 Modes of Op. - Ant. Tilt - Man. (3)

Answer 15

Antenna (A1) Modes of Operation *Antenna Tilt Circuitry: oMANUAL, cont. §Amplified output of U4 and U6 drives tilt motor generator (A1B2). §Tilt error and rate feedback signals decrease in amplitude.

Question 16

Ant. Circuit Diagrams - A1 Modes of Op. - Gyroscope

Answer 16

Antenna (A1) Modes of Operation *Simulated Gyroscope (Gyro) (A7): oAircraft pitch and roll maneuvers are simulated by two resolvers. oCircuitry automatically compensates for these maneuvers by driving reflector in opposite direction.

Question 16

Ant. Circuit Diagrams - A1 Modes of Op. - Tilt Limit (2)

Answer 16

Antenna (A1) Modes of Operation *Tilt Limit Switches, cont.: oWhen S2 or S3 open, tilt rate feedback (LOW) is removed. oMaximum tilt rate feedback (HI) is algebraically summed. oTilt motor generator (A1B2) slows.

Question 17

Ant. Circuit Diagrams - A1 Modes of Op. - Tilt Limit Switch

Answer 17

Antenna (A1) Modes of Operation *Tilt Limit Switches (A1S2 and A1S3): oNormally Closed (NC) microswitches oPrevent antenna reflector assembly from driving against mechanical stops with excessive force

Question 18

Ant. Circuit Diagrams - A1 Modes of Op. - Gyroscope (2)

Answer 18

Antenna (A1) Modes of Operation *Simulated Gyroscope (Gyro) (A7), cont.: oInformation enabled when ANT STAB switch (A5S21) placed in GYRO position.oOutputs of simulated Gyro resolvers applied to tilt stabilization resolver.

Question 19

Ant. Circuit Diagrams - A1 Modes of Op. - Gyroscope (3)

Answer 19

Antenna (A1) Modes of Operation *Simulated Gyroscope (Gyro) (A7), cont.: oCombines simulated Gyro inputs and antenna reflector assembly position information oOutputs STAB ERROR signal to R31 via energized relay K8 §STAB and TILT ERROR signals algebraically summed across R30, R31, & R33. §U4 and U6 amplify signal which drives reflector to compensate for aircraft maneuvers.

Question 20

Which of the following are antenna (A1) azimuth modes of operation? Select all that apply.
KEEPS OUTPUT CONTSTANT
USES A MOSFET
HAS GOOD STAGE ISOLATION
CONTROLS THE GAIN

Question 20

Match each antenna (A1) mode of operation with its function. CHARACTERISTICS : SENSITIVITY SIGNAL-TO NOISE RATIO SELECTIVITY FIDELITY DEFINITION: THE ABILITY TO SEPARATE A DESIRED FREQUENCY FROM ALL OTHER FREQUENCEIES THE AMPLITUDE OF A DESIRRED SIGNAL AS COMPARIED TO THE NOISE AMPLITUDE THE ABILITY OF A RECEIVER TO REPRODUCE WEAK SIGNALS THE ABILITY TO ACCURATELY REPRODUCE, IN ITS OUTPUT THE SIGNAL THAT APPEARS AT ITS INPUT

Question 21

Simulated Gyro information is enabled when the ANT STAB switch is placed in the GYRO position.

Question 21

Ant. Circuit Diagrams - Assoc. Ant. Circuitry - Sweep

Answer 21

Associated Antenna (A1) Circuitry *Sweep Resolver (A1B5): oReceives reference sweep from synchronizer (A3) oProduces X- and Y-resolved sweep signals used in indicator (A4)

Question 22

Ant. Circuit Diagrams - Assoc. Ant. Circuitry - Debouncer

Answer 22

Associated Antenna (A1) Circuitry *Heading Marker Debouncer (U5): oBlocks spurious signals from heading marker switch (A1S1) §Signal must be 40 ms long to pass heading marker debouncer. §Trigger applied to synchronizer (A3) to develop heading marker on indicator (A4).

Question 22

Ant. Circuit Diagrams - Assoc. Ant. Circuitry - Power Supply

Answer 22

Associated Antenna (A1) Circuitry *Power Supply Inverter Group (A1PS1): oSupplies antenna (A1) with all required operating voltages §Input: 115 VAC 60 Hz §Output: +5, +15, +12, -12, +28, +40, and -40 VDC oContains DC-to-AC (direct current-to-alternating current) static inverter oReduces 115 to 26 VAC 400 Hz via a stepdown transformer

Question 23

The power supply inverter group (A1PS1) supplies the antenna (A1) with all required operating voltages.

Question 24

True or False - The sweep resolver (A1B5) transmits the reference sweep from the synchronizer (A3).

Answer 24

The answer is False. The sweep resolver (A1B5) receives the reference sweep from the synchronizer (A3) and produces the X- and Y-resolved sweep signals used in the indicator (A4).

Question 25

Ant. Circuit Diagrams - Antenna (A1) Safety Procedures

Answer 25

Antenna (A1) Safety Procedures *Ensure all jewelry has been removed. *When taking measurements, do not allow loose clothing to contact moving parts.

Question 26

Ant. Circuit Diagrams - Antenna (A1) Safe. Proc. - Warning

Answer 26

High voltages and currents are present whenever the antenna (A1) unit is powered up. Be sure to have equipment set up properly for the measurements to be taken to avoid damage to equipment or harm to personnel.

Question 26

When working around an antenna, do not allow any loose clothing to encounter moving parts.

Question 27

Ant. Circuit Diagrams - Theoretical TS. - No Azimuth - 4-2

Answer 27

Theoretical Troubleshooting *No Antenna (A1) Azimuth Rotation oTable 4-2, Fault 4 ANT: §There is no antenna (A1) azimuth rotation. §Major Test Point (MTP) A1TP5 waveform missing.

Question 28

Ant. Circuit Diagrams - Theoretical TS. - No Ant. - 4-12

Answer 28

Theoretical Troubleshooting *No Antenna (A1) Azimuth Rotation oTable 4-12, Step 3-1:

Question 28

When troubleshooting the antenna (A1) with no azimuth rotation, use step 3-1 from Table 4-12.

Question 29

Perform BITE test is the first maintenance procedure from Table 4-12 when troubleshooting the antenna (A1) with no azimuth rotation.

Question 30

Which antenna (A1) mode of operation drives the antenna reflector back and forth around the setting of the azimuth control (A5B2)?A.SECTOR B.SCAN C.STOP D.AUTO

Answer 30

The correct answer is A. The width of the sector is set by the sector width control (A5R1), from 40 to 140 degrees. The direction the antenna reflector assembly rotates depends on the phase of the azimuth drive voltage.

Question 31

The sweep resolver (A1B5) receives the reference sweep from the synchronizer (A3) and produces the X- and Y-resolved sweep signals used in the indicator (A4).

Question 31

To follow antenna (A1) safety procedures, be sure to have test equipment set up properly for the measurements to be taken to avoid damage to equipment or harm to personnel.

Question 32

When troubleshooting the antenna (A1) with no azimuth rotation, the next maintenance procedure to take after performing a BITE test is to observe waveform at U7 (OUT).