VOR – VHF Omnidirectional Range stands for Very High Frequency Omni-directional Range officially adopted by ICAO in 1960 developed by the United States in 1937 and put in use by them in 1946 is a short range navigation system for Airplanes that helps an Airplane in receiving signals from a ground transmitter to determine its position and choose or maintain its course in flight. It uses frequencies in the bandwidth of 108.0 to 117.95 Mhz (Megahertz)
The principe of a VOR is bearing measurement by phase comparison. It uses a phase antenna that transmits 30 times a second and sends out a 30Hz reference signal in all directions. The phase difference between the reference signal and the signal amplitude is the bearing from the VOR station to the receiver relative to magnetic north. The signal works on the line of sight philosophy between the transmitter and the receiver upto a range of 200 miles and gives the Aircraft its position with respect to bearing and distance in Nautical miles.
The Ground station or a beacon as the pilots call it will usually be identified by a 3 letter code like DPN for Delhi, BBB for Mumbai or JFK for a place like New York Kennedy International Airport.
Did you know that a VOR shares its frequency bandwidth with the ILS signals ??
If yes tell us the bandwidth and we will throw some light on it in the next write up as well, till then Happy VOR Hunting as we call it.