3D155 Volume 2 URE Flashcards
Learn Important Stuff In Volume Two
The airport surveillance radar (ASR) is used in which air traffic control (ATC) radar mission?
Terminal Control Area
Azimuth resolution is directly related to what radar set characteristic?
Antenna beam width
The airport surveillance radar transmitter site should be located more than 1/2 mile from the primary instrument approach path and touch-down point so that these areas
do not fall within receiver recovery time.
The point designated as touchdown for a precision approach radar (PAR) is normally how many feet from the end of the runway?
1,000 exclusive of any overruns.
Siting a precision approach radar (PAR) for multiple runway approaches can cause you to locate the unit outside the optimum coverage areas If this occur what would be the best location for the radar system?
A position where it gives the best coverage to your most important runway.
In the AN/GPN-22 precision approach radar (PAR) system, frequency diversity is used in the scan mode to eliminate
large target fluctuations and provide target enhancement.
In the AN/GPN-22 precision approach radar (PAR) system, frequency diversity is accomplished by transmitting two 1 microsecond (usec) pulses that are composed of two X-band frequencies separated by
37 MHz
In the AN/GPN-22 precision approach radar (PAR), the coherent and non-coherent input to the moving target indicator (MTI) detector is outputted as
bipolar video
Once a track is established in the AN/GPN-22 precision approach radar (PAR), what device uses error data obtained from the receive signal to predict where the target will be during the next track interval?
Target Data Computer (TDC)
How many narrow band filters does the AN/GPN-22 precision approach radar (PAR) employ to convert a shift in intermediate frequency (IF) to a range error signal?
24
In the AN/GPN-22 precision approach radar (PAR), the operational program is locked to the real-time radar operations by the interrupt command signal from the
dual channel receiver processor
At what interval does the AN/GPN-22 precision approach radar’s (PAR) target data computer (TDC) perform system fault monitoring?
Once every 2 seconds.
In the AN/GPN-22 precision approach radar (PAR), what are the three modes of operation with respect to data loop operation?
Command, input, and output.
In the AN/GPN-22 precision approach radar (PAR), the data loop interface logic circuitry used in each of the subsystems is commonly called
repeater logic.
The target data computer in the AN/GPN-22 precision approach radar (PAR) processes the site parameter panel data once
every 2 seconds.
The AN/GPN-22 precision approach radar (PAR) required input voltage is 3-phase,
208 VAC
AN/GPN-22 precision approach radar (PAR) emergency power is supplied by a
12-volt, direct current (VDC) battery.
On the AN/GPN-22 precision approach radar (PAR) radar set controls (RSC), an ‘OVER TEMP’ fault lamp indicates
excessive current draw or insufficient cooling.
What capability makes the traveling wave tube (TWT) much more versatile than the magnetron?
It is a wide band amplifier and not an oscillator.
What is the original source of the continuous wave (CW) radio frequency (RF) drive in the AN/GPN-22 precision approach radar (PAR)?
37-megahertz (MHz) crystal oscillator.
In the AN/GPN-22 precision approach radar (PAR), the stabilized master oscillator (STAMO) multiplies the continuous wave (CW) transmitter drive signal to the
X-band
The purpose of the traveling wave tube (TWT) radar modulator A6 in the AN/GPN-22 precision approach radar (PAR) transmitter is to
provide voltage amplification and trigger shaping to the TWT modulator trigger.
In the scan mode, the AN/GPN-22 precision approach radar (PAR) can direct the radio frequency (RF) beam to how many separate beam positions?
439
Which of the following is an off-line test performed on the antenna position control unit (APCU) in the AN/GPN-22 precision approach radar (PAR)?
Rebound
The AN/GPN-22 precision approach radar (PAR) transmit/receive (T/R) section
prevents receiver damage by the transmitter high-power pulse.
As the range increases, the sensitivity time control (STC) attenuation in the AN/GPN-22 precision approach radar (PAR) is stepped down in what increments?
10dB
What is the total number of automatic alignment procedures to be performed by the timing generator during dead time in the AN/GPN-22 precision approach radar (PAR)?
Eight
Which AN/GPN-22 precision approach radar (PAR) dual-redundant receiver module performs the filtering, limiting, phase detection, analog-to-digital (A/D) conversion, decommutation, and integration of the azimuth and elevation signals?
Error detector
In the AN/GPN-22 precision approach radar (PAR), the non-coherent mode of operation is used to
detect a target in the presence of moving cutter such as rain.
All of the front panel switches in the special test section of the dual redundant receiver of the AN/GPN-22 precision approach radar (PAR) are disabled during normal operation except for the
LN/LM switch
In the dual redundant receiver of the AN/GPN-22 precision approach radar (PAR) which of the following best describes the fault hierarchy for the automatic fault testing?
Modules that affect the testing of others are tested first.
In the AN/GPN-22 precision approach radar (PAR) signal data converter (SDC), what permits the comparison of echoes from three radar receive periods?
Conversion of bipolar video to a digital form.
In the AN/GPN-22 precision approach radar (PAR), what is the output of the signal data converter (SDC) to the indicator group?
Unipolar video
In single cancellation, what happens to the pulse train after it is time-aligned with the next range scan?
The second range scan is subtracted from the first.
How many radar scans does double cancellation require?
Three
In the AN/GPN-22 precision approach radar (PAR), how many scan periods are required to perform video integration in the signal data converter (SDC)?
Three
What identifies and blanks returns from targets beyond the operating range of the radar?
Second-time-around reduction circuits.
What type of multiplexing is used in the closure, analog, digital, and video/trigger/data channels of the AN/GPN-22 precision approach radar (PAR)?
Time division
Which multiplexing process is used when we combine five different channels into one common channel?
Frequency-division
The most common method of modulation used in remoting is
Amplitude Modulation (AM)
In the AN/GPN-22 precision approach radar (PAR) remoting system, what two types of modulation does the analog data undergo?
Pulse code modulation (PCM) and AM
Which converter is used in both the AN/GPN-22 precision approach radar (PAR) shelter and radar approach control (RAPCON) remoting equipment to convert the parallel 32-bit data words to serial data and back again?
Digital-to-digital (D/D)
In the AN/GPN-22 precision approach radar (PAR) remoting system, which channel is not remoted to the radar unit?
Video/triggers/data
What AN/GPN-22 precision approach radar (PAR) remoting channel is multiplexed but does not modulate a subcarrier, since the frequency range of the information makes it suitable for direct transmission?
Video/triggers/data
Where are the modulated subcarriers that represent the various types of inputs to the AN/GPN-22 precision approach radar (PAR) remoting circuits summed?
Remoting common channel
In the remoting section of the AN/GPN-22 precision approach radar (PAR), what is the purpose of the line driver equalizer circuits?
Frequency compensates the response for cable length.
In remoting signals, line attenuation is greatest at the
higher frequencies.
The precision approach radar (PAR) indicator system indicates an aircraft’s
elevation, range, and azimuth
The precision approach radar (PAR) indicator system displays the decision height cursor
along the elevation glidepath.
Th precision approach radar (PAR) indicator system displays the reference reflector
in azimuth only
The primary function of the refresh memory (RM) in the precision approach radar (PAR) indicator system is to
maintain a flicker-free presentation for the display.
In the precision approach radar (PAR) indicator the top presents elevation versus
range data and the bottom half presents azimuth versus range.
When using the AN/UPM-145 Radar Test Set, you must reduce the input with attenuators if input power exceeds
50 dBm
The AN/UPM-145 output frequency can be adjusted between
8.4 and 10 GHz
After initial turn-on, what is the recommended warm-up period for the AN/UPM-145 Radar Test Set before performing any tests?
5 minutes.
What receiver parameter does minimum discernable signal (MDS) check?
Receiver sensitivity.
The AN/GPN-20 airport surveillance radar (ASR) primary power input is 3-phse,
120/208 VAC
The AN/GPN-20 airport surveillance radar (ASR) provides emergency obstruction light operation for a minimum of
10 minutes.
What effectively eliminates moving target indicator (MTI) blind speeds at the speeds seen in air traffic control?
Staggered pulse repetition frequency (PRF)
Blind speed is a target speed at which successive radar returns changes phase by
180 degrees.
In dual frequency diversity mode, the overall AN/GPN-20 airport surveillance radar (ASR) system timing is derived from the
selected master channel.
In the AN/GPN-20 airport surveillance radar (ASR) transmitter, what causes the magnetron to oscillate?
High-voltage negative pulse from the pule transformer.
What is used to regulate the output of the AN/GPN-20 airport surveillance radar (ASR) transmitter’s high voltage power supply?
Conduction time of six silicon controlled rectifiers (SCRs)
The output voltage adjustment for the AN/GPN-20 airport surveillance radar (ASR) high voltage power supply is located
on the transmitter front panel.
What AN/GPN-20 airport surveillance radar (ASR) meter is a good indicator of the transmitter output power?
Magnetron current.
The time necessary to quickly disconnect the transmitter and connect the receiver to the antenna is called
transmitter/receiver (TR) recovery time
A diplexer enables the use of two
operating systems with one antenna.
Which component consists of two radio frequency (RF) filters?
Diplexer
Radio frequency (RF) to the antenna makes the transition from fixed to rotating waveguide within the
rotary joint.
When the horizontal plane of the transmitted beam of an airport surveillance radar (ASR) is on a target for less time, the
greater is the azimuth resolution.
What is the ideal horizontal beam width for the AN/GPN-20 airport surveillance radar (ASR) antenna at the half power point?
1.5 degrees
A passive feedhorn is used to achieve greater control over
received ground reflections
How will the final optimum tilt angle for the AN/GPN-20 airport surveillance radar (ASR) antenna be determined?
Survey and flight check
To change the AN/GPN-20 airport surveillance radar (ASR) receiver stable local oscillator (STALO) frequency you must
change the internal very high frequency (VHF) oscillator crystal.
The AN/GPN-20 airport surveillance radar (ASR) preamplifiers are designed for stability at the
intermediate frequency (IF), with low noise figure.
The AN/GPN-20 airport surveillance radar (ASR) normal intermediate frequency (IF) amplifier provides IF
amplification, bandpass filtering, video detection, and video amplification.
The AN/GPN-20 airport surveillance radar’s (ASR) log amplifier is a nonlinear device that
amplifies all echo returns to near equal output levels.
The phase of the AN/GPN-20 airport surveillance radar’s (ASR) locked coherent oscillator (COHO) signal is determined by the
magnetron pulse.
A phase detector that produces a large change in output voltage for a small change in input signal phase will
have good moving target visibility.
Most moving target indicator (MTI) phase detectors are designed to develop a
triangular output characteristic.
What should be the basis for adjusting the intermediate frequency (IF) gain in the AN/GPN-20 airport surveillance radar (ASR)?
Signal-to-noise ratio.
The point at which sensitivity time control (STC) wave shape ends is the
radio frequency (RF) or intermediate frequency (IF) baseline.
Antilog circuits may be used to reduce the gain of
noise.
In the AN/GPN-20 airport surveillance radar (ASR), what two signals are mixed in the automatic frequency control (AFC) mixer to produce a signal representative of the difference between the magnetron and stable local oscillator (STALO) frequency?
Attenuated transmitter pulse and STALO original
In the AN/GPN-20 airport surveillance radar (ASR), at what limit from center frequency does the automatic frequency control (AFC) circuitry stop tuning and shut off the transmitter high voltage?
+/-4 MHz
The aster timing signal in the AN/GPN-20 airport surveillance radar (ASR) video processor, establishes the basic radar-timing period (range cell) of
.467 usec
What circuit in the AN/GPN-20 airport surveillance radar (ASR) video processor converts bipolar analog video into a digital form?
Quantizer
In the AN/GPN-20 airport surveillance radar (ASR) video processor, either log or normal video is selected for input in to the moving target indicator (MTI)/normal enhancer circuit by the
normal log fast time constant (FTC) card
What is a measure of the ability to detect a small moving target in ground clutter?
Subclutter visibility
What function of AN/GPN-20 airport surveillance radar (ASR) range azimuth gating (RAG) is used to indicate runway, air route, or approach pattern?
Azimuth strobe gating
The maximum amount of land line allowed between the AN/GPN-20 airport surveillance radar (ASR) and operations site is
12,000 feet
For how many minute is the AN/GPN-20 airport surveillance radar (ASR) control memory energized by the temporary power supply when a power failure occurs?
10
What AN/TPX-42A air traffic control identification friend or foe/selective identification feature (IFF/SIF) component generates ode interrogation triggers?
Coder-synchronizer
In the AN/TPX-42A’s range azimuth beacon monitor (RABM), which device isolates the receiver input from the transmitter output?
Diplexer.
What is the frequency of the transmitted output signal from the range azimuth beacon monitor (RABM)?
1090 MHz
In the AN/TPX-42A transfer switching drawer assembly (TSDA), the amplitude normalizer circuits limit inputs to how many volts before routing the signals to other circuits?
5
In the AN/TPX-42A, which trigger is used to develop the interrogator side lobe suppression (ISLS) switching trigger?
P1
An interrogator side-lobe suppression (ISLS) diplexer is used in lieu of an ISLS switch when the radar system has
only one DC-coupled rotary joint for IFF/SIF.
How does turning the AN/TPX-42A’s gain time control (GTC) switch, on the front panel of the interrogator/receiver (I/R) unit, from OFF to ON affect the receiver’s gain?
Reduces the gain of close-in replies.
What type of information does selective identification feature (SIF) Mode C reply represent?
Altitude
In the AN/TPX-42A video signal processor, what is the name of the new azimuth computed between the on-target (OT) and end-of-target (EOT) azimuths?
Beamsplit azimuth
One of the functions of the AN/TPX-42A line-compensator assembly is to
reestablish a 3:1 ratio between triggers and video.
What component in the AN/TPX-42A video signal processor monitors for the possible interference condition called garble?
Reply detection unit
The reply buffer used with the AN/TPX-42A video signal processor (VSP) memory unit can hold up to how many reply messages per pulse recurrence time (PRT)?
32
Which switch on the AN/TPX-42A interrogator set control (B-box) determines how long the video signal processor (VSP) is allowed to process video?
Range Select.
On the interrogator set control (B-box), if the TARGET LOAD indicator comes on, it’s indicating that the programmable indicator data processor (PIDP) II is processing more than
300 targets.
What is the primary advantage of having two operator keyboards for each control indicator group?
Enables one controller to ‘work’ active traffic and the remaining controller to perform flight data entry/modification, handoffs, etc.
What function of the programmable indicator data processor (PIDP) II alerts the controller should the selected tracked targets deviate greater than +-300 feet from the controller assigned or current altitude?
Altitude monitoring
In the event of a power loss the uninterruptible power supply is capable of operating the entire programmable indicator data processor (PIDP) II OL-475 equipment rack for period of how many minutes?
10
What device is used to specify a screen location to off center the sweep origin of an OD-153 indicator?
Position entry module
In the programmable indicator data processor (PIDP) II, what service does the low-altitude alerting system perform?
When a tracked target enters one of 1024 geographic sectors and is at or below the altitude set for the sector, the tracked target begins to flash and the audible alarm is sounded.
To maintain synchronization with air route traffic control center (ARTCC) equipment, an interfacility communications adapter (ICA) at idle
transmits a pattern of ones and zeroes continually until the start of data.
If the programmable indicator data processor (PIDP) II operation program detects a data transmission error from an air route traffic control center (ARTCC), the message is
ignored.
In the programmable indicator data processor (PIDP) II display interface, how often does a sector interrupt occur?
Every 11.25 degrees from north (0degrees)
In the programmable indicator data processor (PIDP) II display interface, what message causes the display to update the targets in its memory so that a wedge follows the sweep around the cathode ray tube (CRT)?
Sector number message
In a 2-line character block on the OD-153 airport surveillance radar (ASR) indicator, the second line consists of three decimal digits representing
reported altitude in hundreds of feet.
On the OD-153 airport surveillance radar (ASR) indicator display, the identification position (I/P) or special position identifier (SPI) target symbol may be best described as a
continually expanding and shrinking circle.
When the system computer is disengaged, the OD-153 airport surveillance radar (ASR) indicator operates as
a conventional plan-position indicator (PPI).
When off-line is selected on the digital bright radar indicator tower equipment’s (DBRITE) digital scan converter (DSC) control panel, what mode is available for presentation?
built-in tests.
Which boards are in digital bright radar indicator tower equipment’s (DBRITE) digital scan converter (DSC)?
Interface, PPI, synthetic.
What is the maximum number of digital bright radar indicator tower equipment’s (DBRITE) display units that can be driven by a digital scan converter (DSC)?
Four
The type of remote control unit (RCU) used with the digital bright radar indicator tower equipment’s (DBRITE) is determined by the
type of automation system connected to the digital scan converter (DSC) cabinet.
In the digital bright radar indicator tower equipment’s (DBRITE) system, when a built-in test (BIT) function detects a circuit failure, an error code that corresponds to the failure is shown on
the BIT readout panel of the DSC containing the fault.
On the digital scan converter (DSC) control panel of the digital bright radar indicator tower equipment’s (DBRITE), the off-line built-in test BIT) is disabled by setting the
BIT TEST switch to ONLINE.
