Radiobeacon

A radio beacon is a radio station that automatically and continuously sends signals as an aid to air and sea navigation.

Types

There are basically two types of basic beacons:

Navigation scheme using an NDB.

• NDB (Non-Directional Beacon, non-directional beacon): This radio is the oldest and the simplest of both. The station sends a radio signal, of fixed frequency, which can be captured from all directions. Using an ADF instrument Automatic Direction Finder) aboard the plane, the pilot can select the frequency of that radio station, which knows by the navigation charts and observe the needle of the instrument, which indicates in which direction the radiofaro is located. The NDBs are located along the main airline routes, and especially in the vicinity of the airports, where they are still very useful for the pilots when they perform approach manoeuvres with little or no visibility. The emission is made in average frequency and the range is about 30 nautical miles (about 50 kilometers).

A VOR radio in Beijing.

• VOR (Very High Frequency Omnidirectional Range, Very high frequency omnidirectional radiophar): it is a more modern and more complete radiophare than the previous one. The station sends a double signal, of which one is fixed, comparable to that of the NDB. The other is a signal that is issued through a device that rotates fast and continuously at 360 degrees. This way the plane receives a double signal from the station in question. The VOR instrument on board, once the pilot has selected its frequency, as indicated by the navigation letters, informs not only of the direction in which the radio is located, but also on which radial the plane is flying over the station. The radial is the flight direction expressed in degrees of the Earth sphere, in which the VOR transmitter becomes the center. Thus, a plane may be flying directly to a VOR in the radial 270 (output), which means that it is approaching the station in the east-west direction, while another plane may also be flying directly to the VOR, but in the radial 180 (output), in which case it approaches the station in the north-south direction. This allows you to fly accurately on increasingly dense routes and approaches. The VOR radio broadcast is made in very high frequency (VHF) and its range is about 80 miles (about 140 kilometers).

The VOR has in many cases incorporated a DME device Distance Measuring Equipment, that is, remote metering equipment), which allows the pilot, if his instrument also has this system, to know the exact distance from the plane to the VOR. The importance of this additional data is evident. The distance identification is performed by the device on board comparing the two radio signals received from the VOR. When a VOR radiophare has the distance measurement system is called VOR/DME. On the contrary, there are also broadcasters that are only DME, that is, they serve exclusively to know the distance. These stations are usually located in the areas of the airports to facilitate approach manoeuvres.

Some VORs used by civil aviation are at the same time radiofares of military use. In such case they are called VORTAC (the term TAC refers to TacticalI mean, tactical.

The VOR, like the NDB, serves as much help to navigation when it flies towards it as when the plane moves away. Both instruments are also used to determine a position, which is done by establishing intersections that result from the point where the addresses are crossed from or to two stations.

Both radionavigation systems are still in widespread use around the world, although it is expected that in the coming years they will begin to be used in a declining fashion following the advent of the GPS Global Positioning System, global positioning system) that allows the position of an aircraft to be known with great accuracy through satellite signals.