VHF Omnidirectional Range (VOR) - Ch 4

Question 1

VHF Omnidirectional Range

Answer 1

108.00 - 117.95MHZ 
Terminal Ones (close to AP): 108-112
En Route: 112-118
3 Letter Ident 
0.05 separation 
Bearings from VORs are magnetic bearing 
Variation applied at the station

Question 2

ILS Frequency Range

Answer 2

108-112MHZ

Odd number first after decimal

Question 3

2 Types of VOR

Answer 3

Conventional VOR (CVOR)

Doppler VOR (DVOR)

Question 4

Conventional VOR

Answer 4

Reference: Frequency Modulated

Variable: Amplitude Modulated

Question 5

Doppler VOR

Answer 5

Reference: Amplitude Modulated

Variable: Frequency Modulated

Question 6

DVOR

Answer 6

More accurate, newer and more modern

Better for use in confined areas

Less susceptible to siting errors and thus better for using in confined areas

Question 7

VOR Self Checking

Answer 7

Check for any drifting of the signal I.e:

• more than +/- 1 degree
• Signal must be no less than 15%
• Monitor itself to make sure that it is working

If not satisfied, it will remove ident and shut down the transmitter

Question 8

Cone of Confusion

Answer 8

35 degrees either side

ICAO: No more than 50 degrees

Question 9

Types of VOR

Answer 9

• En Route
• Terminal (TVOR)
• Test VOR (VOT)

Can be used to transmit ATIS - airfield wx

Question 10

Equipment for VOR

Answer 10

An Antenna
VOR receiver + control unit
Indicator System (RMI, OBI, HSI)

Question 11

RMI

Answer 11

QDM - Points at beacon

QDR - Tail of arrow, radial that the AC is on (from beacon)

Question 12

OBI

Answer 12

Either TO/FROM beacon
Full scale deflection = 10 degrees either side
Each Dot = 2 degrees
TO/FROM Indicator

Question 13

HSI

Answer 13

Horizontal situation indicator
5 dots - 2 degrees for each dot
AC HDG will be relevant for these questions

Question 14

Range

Answer 14

Proportional to the power of the signal
Range = 1.23 ( square root of RX + square root of Tx)
Limited by line of sight