Pt/Sinais de Radio: Difference between revisions

[[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 [http://en.wikipedia.org/wiki/Non-directional_beacon Non-Directional Beacon ('''NDB''')] is the most basic type of radio beacon. The equipment on board of our aircraft will have to figure out where it is. Any (music) radio station is also a NDB. The typical frequencies of a NDB can be found on the [http://en.wikipedia.org/wiki/Medium_wave AM Medium band] (530 kHz to 1700 kHz) but during flight planning we shall discover NDB's outside this range.

It ''is'' possible to calculate the distance towards a NDB station. For that a pilot flies on a 90 degree angle opposite the station (one wing-tip pointing towards the station). The pilot measures the time it takes to fly a number of degrees on the compass. From the time it takes, the number of degrees and the ground speed the pilot can calculate the distance towards the station.

Very modern receivers can estimate the distance towards a NDB station by the azimuth towards the station.

In the Americas the navigational NDB's operate 530 kHz to 1700 kHz with 10 kHz increments. The rest of the world uses 531 kHz to 1602 kHz with 9 kHz increments. NDB's outside these ranges most probably serve also other purposes, like music stations or DGPS stations.

The range of a typical NDB can be up to 75 NM. When using [[LFR]] the range can be bigger but less accurate. The higher the aircraft the longer the range.

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 is good enough to find fixes on a map and can be used for point-to-point navigation. It is cheap to operate.