chapter  10
VHF omnidirectional range
Pages 4

VOR is a short/medium-range navigation system

operating in the 108-117.95 MHz range of

frequencies. This means that the radio waves are

now propagated as space waves. The problems

that were encountered with ground and sky waves

in the LF and MF ranges are no longer present

with a VHF system. VOR navigation aids are

identified by unique three-letter codes (derived

from their name, e.g. London VOR is called

LON, Dover VOR is called DVR etc.). The code

is modulated onto the carrier wave as a 1020 Hz

tone that the crew can listen to as a Morse code

signal. Some VOR navigation aids have an

automatic voice identification announcement that

provides the name of the station; this alternates

with the Morse code signal. The location of the

VOR navigation aids (specified by latitude and

longitude) together with their carrier wave

frequencies is provided on navigation charts as

with ADF.