Radio beacons: Difference between revisions

A [http://en.wikipedia.org/wiki/Radio radio] is a generic term for the transmission of electromagnetic waves. In the above comparisons, a radio beacon is the one that is shouting or that is laying out the ropes. A beacon can include information, it can even send out music. Two-way communication is possible where the equipment on-board questions equipment on-ground or the beacon is used for ATIS or Tower communication.

[[File:Radio beacon NDB.png|frame|Equipment finds the direction of the strongest signal of the NDB and shows this on a compass rose.]]

[[File:Pictogram NDB.png|frame|NDB symbol]]

A NDB is sensitive for weather and ground influences, it can get reflected and distorted making a bearing less reliable. As a distance measuring tool the NDB is not quite suited. But it's perfect to find fixes on a map and can be used for point-to-point navigation. Next to that it is cheep to operate.

The [http://en.wikipedia.org/wiki/Low_frequency_radio_range Low Frequency Radio Range ('''LFR''')] is a [[NDB]] that operates at a frequency of 190 to 535 kHz, the [http://en.wikipedia.org/wiki/Long_wave long wave] frequency and a bit above. Across the world there are plenty of LFR stations but it is claimed that LFR is phased out.

There are two ways to figure out where the [[NDB]] is relative to the aircraft. Rotating an antenna '''manually''' until finding the direction of the strongest signal (loudest transmission) or have this done '''automatically''' (or electronically). The equipment (or person) to do so is called a [http://en.wikipedia.org/wiki/Radio_direction_finder Radio Direction Finder ('''RDF''')].

An '''ADF''' is ''not'' a radio station, is the the equipment on board of the aircraft to perform [[RDF]] automatically, the Automatic Direction Finder (ADF). Often [[NDB]] stations are called ADF stations but that is technically incorrect.

[[File:Radio beacon VOR.png|frame|The VOR beacon tells the equipment what course to fly to intercept the beacon.]]

[[File:Pictogram_VOR.png|frame|VOR symbol]]

While it is more expensive to operate a VOR station compared with a [[NDB]] the benefits are obvious. The signal is less hindered by unwanted reflections and other interferences, when the signal is received it is accurate, it takes away confusion about North, since it's oriented True North, it can be used for automated flight and the receivers are more reliable.

[[File:Pictogram_VOR-DME.png|frame|VOR-DME symbol]]

Distance Measuring Equipment ('''[[DME]]''') uses the same frequencies as a [[VOR]]. A DME tells the equipment on board of the aircraft the distance towards the transponder. There is two-way communication between the equipment on-board and the DME station to calculate the result.

For position finding only one VOR-DME station is needed since it gives the radial towards the station and the distance. Knowing the position of the VOR-DME station on the map will give the position of the aircraft on that map.

An '''[[ILS]]''' ''can'' be used as a [[NDB]] beacon but it's range is limited and depends very much on the position of the aircraft towards the station (and runway). The LOC signal of an ILS transmits only one radial, the heading towards the runway. It should only be used as a system for landing and not for navigation.

The military uses a slightly different system as the civilian version. The military uses something named '''[[TACAN]]''' that operates in the frequency band 960-1215 MHz overlapping the VOR frequency range. It combines a [[VOR-DME]] and includes an azimuth feature that provides more accurate navigation.

[[File:Pictogram_VORTAC.png|frame|VORTAC symbol]]

Often the [[VOR-DME]] part of the [[TACAN]] is also made available for civilian navigation. If so, the beacon is called a '''VORTAC''', but the use is as a normal [[VOR-DME]], in the normal frequency range. The range of the beacon varies. Most have the same range as a [[VOR-DME]] but many will have different ranges.

[[Radio navigation]]

*http://en.wikipedia.org/wiki/Radio_navigation

*http://en.wikipedia.org/wiki/RNAV

  This chapter to be removed after being "done".