VHF OmniRange (VOR)

Question 1

What does VOR stand for?

Answer 1

VHF OmniRange

Question 2

The aviation industry uses three navigation systems that operate in VHF frequency band:

Answer 2

VOR, Localizer, and Marker Beacons

Question 3

The VOR operates on what frequencies?

Answer 3

108.00MHz to 117.95MHz

Question 4

A receiver on the aircraft receives the energy and demodulates the signal. That results in what?

Answer 4

A 30Hz sine wave called the Variable Signal

Question 5

What is the varying energy transmitted as from a VOR station?

Answer 5

a Variable Signal

Question 6

For the aircraft to determine the field direction:

Answer 6

the transmitted signal is Amplitude Modulated with a reference signal of varying frequency centered on 9.96KHz

Question 7

What do Radials do?

Answer 7

Give imaginary lines on the ground that radiate in all directions from the VOR station

Question 8

What depicts the VOR radials on Sectional Charts?

Answer 8

Compass Roses

Question 9

What is the short range navigation system used throughout most of the world?

Answer 9

VOR

Question 10

A well designed and installed VOR receiver can be accurate to within:

Answer 10

One compass degree

Question 11

What does CDI stand for?

Answer 11

Course Directing Indicator

Question 12

What does a CDI do?

Answer 12

Allows pilots to select and determine their relationship to the selected course

Question 13

What does OBS stand for?

Answer 13

Omni Bearing Selector

Question 14

What does the pilot use an OBS for?

Answer 14

to set the course

Question 15

What was one of the early ways to indicate VOR bearings?

Answer 15

on a Radio Magnetic Indicator (RMI)

Question 16

What does the RMI show?

Answer 16

the heading on the compass card and the bearing to the VOR station

Question 17

What does RMI not have?

Answer 17

A CDI needle

Question 18

Each dot on the CDI represents:

Answer 18

30 micro Amps and two degrees of course error

Question 19

How else can VOR information be displayed?

Answer 19

on a Horizontal Situation Indicator (HSI)
Also known as a
Pictorial Navigation Indicator (PNI)

Question 20

VHF navigation receivers are almost identical in appearance to VHF communication receivers. A key difference is that:

Answer 20

a Navigation Transceiver does not have a squelch control. They do have an extra output for the navigation signal and an identification filter

Question 21

How are VOR stations identified?

Answer 21

a 1020 Hz Morse Code signal which makes the voice transmissions more understandable

Question 22

What is the heart of the VOR system?

Answer 22

the receiver

Question 23

What is a Localizer or LOC?

Answer 23

a system used to guide the aircraft down to the runway and is part of the ILS

Question 24

What does ILS stand far?

Answer 24

Instrument Landing System

Question 25

What is commonly used in light/smaller aircraft?

Answer 25

a transceiver. And in some systems is combined with VHF comm. Transceiver

Question 26

What do many large aircraft use?

Answer 26

an Integrated Flight Management System that includes both navigation and communication functions

Question 27

How many antennas does the VHF Nav system use?

Answer 27

two antennas typically mounted one to each side of the airframe

Question 28

What type of aircraft is the Whip style antenna used on?

Answer 28

light or slower flying aircraft that have less of a drag loading on the antenna

Question 29

What is the Whip style antenna normally mounted on?

Answer 29

the vertical stabilizer

Question 30

The Towel Bar style antenna is mounted where?

Answer 30

to either sides of the vertical stabilizer or fuselage

Question 31

What style type antenna is used on higher speed aircraft?

Answer 31

The V style It has a larger footprint and more aerodynamic shape to reduce drag

Question 32

Where is the optimum placement of the V antenna?

Answer 32

forward on top of the fuselage

Question 33

What are Blade style antennas normally used for?

Answer 33

high speed aircraft and mounted to each side of the vertical stabilizer

Question 34

What type of aircraft are Blade style antennas found on?

Answer 34

business type and transport category aircraft

Question 35

VOR testing must be done how often and by whom are they usually performed and logged by?

Answer 35

within the last 30 days usually performed and logged by the pilot

Question 36

What does VOT mean?

Answer 36

VOR Test Facility

Question 37

VOR test readings should not be greater than:

Answer 37

+/- 4 degrees from the desired heading +/- 6 degrees is check is done in the air

Question 38

If the needle moves erratically, darting left and right, this typically is due to:

Answer 38

an internal component (a resolver) that turns with the OBS

Question 39

Anytime a VOR ground station is being worked on, what happens?

Answer 39

the technician turns off the audio ident which warns the pilot not to use the station for navigation

Question 40

If the VOR needle is swinging side to side slowly it is called:

Answer 40

course bends

Question 41

If the VOR needle is swinging side to side fast it is called:

Answer 41

course scalloping

Question 42

What does NOTAM stand for?

Answer 42

Notice to Airmen a notice stating that certain radials of a VOR are unusable

Question 43

What causes both needles to move together like windshield wipers?

Answer 43

propeller or rotor modulation

Question 44

What is propeller or rotor modulation?

Answer 44

the signal from the ground station passed thru the propeller and is "chopped" in the spinning blades

Question 45

For propeller driven aircraft, be sure that the VOR antenna is mounted:

Answer 45

in the location suggested by the airframe manufacturer

Question 46

Rotor modulation in helicopters is more troublesome because:

Answer 46

the rotor blades cover a larger area. this problem is known and filters in radios are provided and intended for helicopter operation