VOR operates in the 108.0 MHz–117.95 MHz band to provide aircraft avionics ability to determine the azimuth (direction/compass heading) the aircraft would have to fly to the VOR, or the azimuth the aircraft is flying from a VOR.

VORs are transmitters that support non-precision (lateral guidance only) approach and en-route procedures. VORs support the low-altitude Victor Airways, high- altitude Jet Routes, conventional-STARs and Departure Procedures (DPs), and Instrument Approach Procedures (IAPs). VORs are also used to define Class B airspace sectors - that is, a volume of airspace controlled by an air traffic controller. 

Conversion to DVOR (Dopplerization)

There are numerous VORs that have signal restrictions due to encroachment of obstacles that block the transmission of VOR signals. These restrictions seriously impact en-route, arrival, and departure procedures. Natural encroachment happens when trees, located outside the boundaries of the FAA-controlled area where the VOR is located, have grown tall enough to cause interference to the VOR signal. Similar interference can be caused by many synthetic obstacles such as newly constructed tall buildings; nearby industrial parks with a high concentration of metal buildings; overhead transmission lines; towers for radio, television, and cell service; and wind farms. Dopplerizing a VOR can mitigate signal-in-space restrictions caused by reflections from obstacles. The FAA procures and installs Doppler VOR (DVOR) electronic kits and antenna kits to dopplerize a conventional VOR. Dopplerization will continue as needed until the DVT program provides new DVORs that will replace conventional VORs as needed.