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What is the primary function of the VOR system?
What is the primary function of the VOR system?
Which frequency band does the VOR system operate within?
Which frequency band does the VOR system operate within?
How does the VOR system determine the bearing of an aircraft?
How does the VOR system determine the bearing of an aircraft?
What role does the sub-carrier frequency play in the VOR signal?
What role does the sub-carrier frequency play in the VOR signal?
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In the context of VOR, what does the term 'omni-directional' refer to?
In the context of VOR, what does the term 'omni-directional' refer to?
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What concept is likened to a VOR system when explaining its function?
What concept is likened to a VOR system when explaining its function?
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What is a characteristic advantage of the VOR system in terms of signal reliability?
What is a characteristic advantage of the VOR system in terms of signal reliability?
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Which of the following describes the output of conventional VOR equipment?
Which of the following describes the output of conventional VOR equipment?
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What is the primary purpose of RMI (Radio Magnetic Indicator) in the context of VOR?
What is the primary purpose of RMI (Radio Magnetic Indicator) in the context of VOR?
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How many possible radials can a VOR beacon produce?
How many possible radials can a VOR beacon produce?
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What does the vertical movement of the CDI needle indicate when navigating using VOR?
What does the vertical movement of the CDI needle indicate when navigating using VOR?
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Each dot on the Course Deviation Indicator represents what deviation from the desired course?
Each dot on the Course Deviation Indicator represents what deviation from the desired course?
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In a VOR system, what is the role of the phase comparator in the detection process?
In a VOR system, what is the role of the phase comparator in the detection process?
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Which type of antenna is primarily used for receiving VOR signals in the VHF band?
Which type of antenna is primarily used for receiving VOR signals in the VHF band?
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How is a TO-FROM indication determined for a VOR station?
How is a TO-FROM indication determined for a VOR station?
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What happens when the VOR receiver detects a problem within the system?
What happens when the VOR receiver detects a problem within the system?
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What is the purpose of the flight control computer (FCC) in the ILS system?
What is the purpose of the flight control computer (FCC) in the ILS system?
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What does the term 'RMI' stand for, and what is its primary function?
What does the term 'RMI' stand for, and what is its primary function?
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What two signals are compared in the phase comparator within a VOR system?
What two signals are compared in the phase comparator within a VOR system?
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What does the term 'bearing' refer to in terms of aircraft navigation?
What does the term 'bearing' refer to in terms of aircraft navigation?
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Which component is responsible for monitoring the reliability of the VOR system?
Which component is responsible for monitoring the reliability of the VOR system?
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What type of data does the VOR station provide for navigating along a selected track?
What type of data does the VOR station provide for navigating along a selected track?
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In which frequency band does the VOR system primarily operate?
In which frequency band does the VOR system primarily operate?
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What is the primary function of the bearings displayed on the electronic flight display instrument system?
What is the primary function of the bearings displayed on the electronic flight display instrument system?
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How does the VOR system convey flight commands to the pilot when there is a course deviation?
How does the VOR system convey flight commands to the pilot when there is a course deviation?
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What would trigger a warning FLAG from the Flight Warning Computer regarding the VOR system?
What would trigger a warning FLAG from the Flight Warning Computer regarding the VOR system?
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Which of the following best describes the role of RMI (Radio Magnetic Indicator) in VOR navigation?
Which of the following best describes the role of RMI (Radio Magnetic Indicator) in VOR navigation?
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What is the function of the LOC/VOR antenna in the VOR system?
What is the function of the LOC/VOR antenna in the VOR system?
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Which of these components on the flight display assists in visualizing course deviations?
Which of these components on the flight display assists in visualizing course deviations?
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What action is taken if the VOR system experiences failure during flight?
What action is taken if the VOR system experiences failure during flight?
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What type of signal does the VOR aircraft receiver compare to determine the bearing?
What type of signal does the VOR aircraft receiver compare to determine the bearing?
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How does the VOR aircraft control unit identify the ground station frequency?
How does the VOR aircraft control unit identify the ground station frequency?
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What is the primary function of the Radio Magnetic Indicator (RMI) in VOR aircraft equipment?
What is the primary function of the Radio Magnetic Indicator (RMI) in VOR aircraft equipment?
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What is the minimum altitude a pilot must fly to receive VOR signals?
What is the minimum altitude a pilot must fly to receive VOR signals?
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What relationship exists between the amplitude modulated signal and the frequency modulated signal in VOR?
What relationship exists between the amplitude modulated signal and the frequency modulated signal in VOR?
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What does the TO-FROM indicator on the VOR indicate when flying to the VOR station?
What does the TO-FROM indicator on the VOR indicate when flying to the VOR station?
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Which component of the VOR system is responsible for receiving the modulated signals from the ground station?
Which component of the VOR system is responsible for receiving the modulated signals from the ground station?
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What does the rotating course card on the VOR display indicate?
What does the rotating course card on the VOR display indicate?
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What kind of diagram is used to represent the omni directional radiation of VOR signals?
What kind of diagram is used to represent the omni directional radiation of VOR signals?
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What fundamental principle does the VOR station utilize to determine the aircraft's bearing?
What fundamental principle does the VOR station utilize to determine the aircraft's bearing?
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Which frequency modulation technique is employed to distinguish the variable phase signal in a conventional VOR?
Which frequency modulation technique is employed to distinguish the variable phase signal in a conventional VOR?
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How are the channels spaced within the VOR system's operational frequency band?
How are the channels spaced within the VOR system's operational frequency band?
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What characteristic of the VOR system ensures that it functions reliably at all times?
What characteristic of the VOR system ensures that it functions reliably at all times?
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Which analogy is used to explain the function of a VOR station?
Which analogy is used to explain the function of a VOR station?
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What is the role of the sub-carrier frequency in the VOR system?
What is the role of the sub-carrier frequency in the VOR system?
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What is the effect of the speed of rotation of the VOR signal on an aircraft's navigation?
What is the effect of the speed of rotation of the VOR signal on an aircraft's navigation?
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What type of energy is radiated by a VOR station?
What type of energy is radiated by a VOR station?
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How many possible radials can a VOR beacon provide for navigation?
How many possible radials can a VOR beacon provide for navigation?
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What happens when the VOR receiver encounters a malfunction?
What happens when the VOR receiver encounters a malfunction?
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What characteristic of the VOR system allows an aircraft’s receiver to detect the same phase on all bearings around it?
What characteristic of the VOR system allows an aircraft’s receiver to detect the same phase on all bearings around it?
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Which statement accurately describes the strength of the variable phase signal compared to the omni-directional signal in the VOR system?
Which statement accurately describes the strength of the variable phase signal compared to the omni-directional signal in the VOR system?
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What specific role does the 30 Hz component of the VOR transmission play within the receiver?
What specific role does the 30 Hz component of the VOR transmission play within the receiver?
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How often does the aerial rotate to transmit the variable phase signal in a VOR system?
How often does the aerial rotate to transmit the variable phase signal in a VOR system?
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What type of diagram is associated with the omni-directional radiation characteristics of the VOR system?
What type of diagram is associated with the omni-directional radiation characteristics of the VOR system?
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Which component of the VOR aircraft equipment is responsible for displaying bearing information?
Which component of the VOR aircraft equipment is responsible for displaying bearing information?
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In the VOR system, what does a phase difference of 180º signify?
In the VOR system, what does a phase difference of 180º signify?
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Which component allows the pilot to manually adjust the course to fly in the VOR system?
Which component allows the pilot to manually adjust the course to fly in the VOR system?
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What is the minimum altitude a pilot must maintain to receive VOR signals?
What is the minimum altitude a pilot must maintain to receive VOR signals?
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What does the TO-FROM indicator signify when the triangle arrow points up?
What does the TO-FROM indicator signify when the triangle arrow points up?
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How does the Course Deviation Indicator (CDI) needle indicate the required direction for course correction?
How does the Course Deviation Indicator (CDI) needle indicate the required direction for course correction?
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What does each horizontal dot on the Course Deviation Indicator signify?
What does each horizontal dot on the Course Deviation Indicator signify?
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What role does the Flight Warning Computer (FWC) play in the operation of the ILS system?
What role does the Flight Warning Computer (FWC) play in the operation of the ILS system?
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How does the VOR receiver initially process the incoming signal?
How does the VOR receiver initially process the incoming signal?
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What electrical signal is generated when the variable 30 Hz signal detects a phase difference?
What electrical signal is generated when the variable 30 Hz signal detects a phase difference?
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Which component of the VOR system is specifically responsible for mixing signals to create an intermediate frequency (IF) signal?
Which component of the VOR system is specifically responsible for mixing signals to create an intermediate frequency (IF) signal?
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What does the red warning flag on the VOR instrument indicate?
What does the red warning flag on the VOR instrument indicate?
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What type of antennas are commonly used for receiving localizer signals in the VOR system?
What type of antennas are commonly used for receiving localizer signals in the VOR system?
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Which component collaborates with the autopilot to convert ILS deviation data into appropriate flying commands?
Which component collaborates with the autopilot to convert ILS deviation data into appropriate flying commands?
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In VOR operations, what does the TO-FROM indicator represent?
In VOR operations, what does the TO-FROM indicator represent?
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What is the main function of the Flight Warning Computer (FWC) in relation to the VOR system?
What is the main function of the Flight Warning Computer (FWC) in relation to the VOR system?
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How does the VOR system convey flying commands when there is a course deviation?
How does the VOR system convey flying commands when there is a course deviation?
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What type of information is primarily displayed on the electronic flight display instrument system concerning VOR?
What type of information is primarily displayed on the electronic flight display instrument system concerning VOR?
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What action does the Flight Warning Computer take when it detects a failure in the VOR system?
What action does the Flight Warning Computer take when it detects a failure in the VOR system?
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Which of these components provides the essential reception of VOR signals within an aircraft's navigation system?
Which of these components provides the essential reception of VOR signals within an aircraft's navigation system?
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Which component is primarily responsible for converting VOR bearing data into commands for the autopilot?
Which component is primarily responsible for converting VOR bearing data into commands for the autopilot?
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In a VOR system, what is the role of the control unit?
In a VOR system, what is the role of the control unit?
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What type of display component assists pilots in visualizing course deviations in relation to VOR navigation?
What type of display component assists pilots in visualizing course deviations in relation to VOR navigation?
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Which of the following best describes the data converted from VOR bearing into flying commands?
Which of the following best describes the data converted from VOR bearing into flying commands?
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Which term refers to the specific paths tracked according to the deviation from a selected course in VOR navigation?
Which term refers to the specific paths tracked according to the deviation from a selected course in VOR navigation?
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Study Notes
VHF Omni Range (VOR)
- VOR operates in the 108-118 MHz band
- Channels are spaced at 50 kHz
- This band overlaps with ILS localizer frequencies (first even decimals)
- VOR creates an infinite number of tracks (360 possible radials) from a beacon
- VOR is unaffected by static and night effects, usable 24 hours
- VOR aircraft equipment includes a receiver, control unit, and indicator
- The receiver picks up signals from ground station antennas at the selected frequency
- The pilot tunes the required VOR frequency and identifies the station using the audio signal
- A minimum altitude of 1000 feet above ground level is required for VOR signal reception
Learning Outcomes
- Working of VOR System
- VOR Aircraft Equipment
- VOR Airborne Loading
- Principle of Automatic Flight Control (Auto Pilot)
Introduction
- The VOR System operates in the 108-118 MHz band with 50kHz spaced channels
- The 108-118 MHz band shares frequencies with ILS localizers.
- The VOR radiates an infinite number of tracks (360 radials)
- It is unaffected by static and night effects and is usable 24 hours.
VOR Ground Beacons
- Various ground beacon locations are shown on an airfield layout
Omni Radial Concept
- VOR beacon is central
- Radials extend outwards from the beacon
- Each radial represents a bearing.
Light House Vs VOR
- A simple analogy for VOR is a lighthouse emitting an omni-directional pulse of light when the beam is pointing north.
- If the rotation speed of the lighthouse beam is known, a distant observer can record the time between the omni directional flash and seeing the beam, to determine bearing.
- VOR stations use VHF energy modulated by a reference phase signal (omni directional) and a variable phase signal that is similar to a rotating beam
Conventional VOR (CVOR) Spectrum
- 30 Hz Amplitude Modulation (AM) - variable phase signal (from physical or electronic rotation)
- 9960 Hz AM - a sub-carrier frequency modulated at 30 Hz with ±480 Hz.
- The 30 Hz signal is the reference phase
VOR Frequency Spectrum
- The VOR spectrum has both a 30 Hz reference signal, and a variable signal
- It utilizes Amplitude Modulation (AM)
Reference Phase Signal
- The VOR carrier signal is Amplitude Modulated (AM) by a 9960 Hz sub-carrier frequency modulated at 30 Hz.
- VOR omni-directional radiation has a circular horizontal polar diagram.
- Aircraft receivers detect the same phase on all bearings around the transmitter. At a given range from the transmitter, an aircraft’s receiver will detect the same phase on all bearings around it
- The 30 Hz component from the transmission is used as a reference for phase comparison which provides bearing.
Reference Signal - Same Phase in All Directions
- The reference signal (30Hz) has the same phase in all directions.
Variable Phase Signal
- This signal is transmitted on the station frequency by an aerial that rotates either physically or electronically 30 times per second.
- The signal is weaker than the omni-directional signal.
- The phase of this signal changes as the aircraft position changes around the circle. The phase can be compared with the FM omni directional signal and displayed to the pilot
Bearing by Phase Comparison
- The phase difference between the reference (30Hz) and variable (30Hz) signals is used to determine bearing.
VOR Ground Antenna
- An image of a VOR ground antenna is provided
VOR Aircraft Equipment
- The aircraft receiver gathers signals from ground station VOR antennas at the selected frequency.
- The bearing information is processed and displayed on Radio Magnetic Indicator (RMI).
- Pilots must fly at a minimum altitude of 1000 ft above ground level to receive VOR signals.
- The pilot tunes the required VOR frequency and identifies the station via the audio signal.
- Pilots can simultaneously switch to VHF radio communication
VOR Indicators
- Omni Bearing Selector (OBS)
- Rotating Course Card
- Omni Bearing Selector
- TO-FROM indicator
- Course Deviation Indicator (CDI)
- Horizontal Dots
Rotating Course Card
- Calibrated from 0 to 360 degrees, indicating the selected VOR bearing for flight.
Omni Bearing Selector (OBS Knob)
- Used to rotate the course card manually to the desired flight point.
TO-FROM Indicator
- Triangle arrow points UP when flying toward the VOR station and DOWN when flying away from it.
CDl (Course Deviation Indicator)
- Needle moves left or right, showing the direction to turn the aircraft back to course.. Indicators show the direction, to turn the aircraft to return to the desired course.
Horizontal Dots
- At the center; each dot represents 2 degrees of deviation from the desired course.
Aerials
- VEE-dipole (whip antennas) are often used for receiving localizer and VOR signals. They are typically located near the aircraft tail.
VOR Station TO-FROM Indicator
- The TO-FROM indicator shows the aircraft’s position relative to the selected VOR station radial.
Example 3-3: Bearing Calculation
- Illustrative examples are provided showing how to determine bearing using the VOR system and its display.
VOR Airborne Loading
- The receiver sends the signal to the preselector for selecting the required VOR frequency and filtering out other frequency components.
- After the preselector, the signal goes to the mixer to mix with the synthesizer frequency to produce an Intermediate Frequency (IF) signal.
- The detector demodulates the IF signal to return to the original signal.
Airborne Loading Diagram
- A diagram illustrates the circuit for VOR airborne loading
- Components include the preselector, mixer, detector, filter, phase comparator, RMI, and synchronizer
The Detected Signal
- The detected signal is applied to two separate circuits.
- The 30Hz variable signal is filtered, amplified and detected. A separate circuit detects the reference 30Hz signal.
- The variable 30Hz and reference 30Hz signals are compared for phase difference in a phase comparator.
- The detected phase difference is converted into voltage that can be applied to the RMI.
Course Deviation, TO/FROM Indications, VOR Equipment, Warnings
- Course deviation, TO/FROM indicators, and related parameters are derived from phase comparisons of 30 Hz signals.
- VOR equipment can detect system problems. A warning flag, typically red, appears on the instrument face.
Auto Pilot
- The ILS interface uses Flight Control Computer (FCC) that monitors ILS deviations—this is applied to the autopilot which converts deviations into instructions for automatic landing.
- Localiser and glideslope deviations appear on the electronic flight display instrument system.
- Flight Warning Computer (FWC) monitors ILS functions and issues warning signals to the pilot.
ILS Auto Pilot Diagram
- A diagram shows the connections between the Flight Control Computer (FCC), Flight Warning Computer (FWC), receivers, and displays.
Auto Pilot
- VOR interface uses the Flight Control Computer (FCC) to monitor VOR bearing and course deviation from the selected track
- The information is converted into commands for following the track
- VOR bearing data, course deviation paths, and distance measurements are displayed on the electronic flight display instrument system
- Flight Warning Computer (FWC) monitors the VOR reliability and issues a warning flag for failures
VOR Auto Pilot Diagram
- A wiring diagram illustrates the communications between VOR components as well as other systems such as other Flight Displays.
The End
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Description
Test your knowledge on the VHF Omni Range (VOR) System and its functionalities. This quiz covers the operation, aircraft equipment, and principle of automatic flight control related to VOR. Learn about frequency bands, channel spacing, and the practical applications of VOR in aviation.
