 Radio Tower of NKR Leimen-Ochsenbach, Germany A Non-Directional Beacon (NDB) is a radio broadcast station in a known location, used as an aviation or marine navigational aid. As the name implies, the signal does not include internal directional information, in contrast to newer navigational aids such as VHF omnidirectional range (VOR). NDB signals follow the curvature of the earth, so they can be received at much greater distances at lower altitudes, a major advantage over VOR. However, the NDB signal is affected more by atmospheric conditions, mountainous terrain, coastal refraction and electrical storms, particularly at long range. Even with the advent of VHF omnidirectional range (VOR) systems and Global Positioning System (GPS) navigation, NDBs continue to be the most widely-used radio navigational aid worldwide. Image File history File links Question_book-3. ...
Image File history File links Size of this preview: 342 × 600 pixelsFull resolution (1024 × 1795 pixel, file size: 246 KB, MIME type: image/jpeg) Antenna tower of NDB NKR Leimen-Ochsenbach, Germany, photographed by myself on July 9th, 2006 Permission is granted to copy, distribute and/or modify this document...
Image File history File links Size of this preview: 342 × 600 pixelsFull resolution (1024 × 1795 pixel, file size: 246 KB, MIME type: image/jpeg) Antenna tower of NDB NKR Leimen-Ochsenbach, Germany, photographed by myself on July 9th, 2006 Permission is granted to copy, distribute and/or modify this document...
Table of geography, hydrography, and navigation, from the 1728 Cyclopaedia. ...
D-VOR (Doppler VOR) ground station, co-located with DME. VOR, short for VHF Omni-directional Radio Range, is a type of radio navigation system for aircraft. ...
D-VOR (Doppler VOR) ground station, co-located with DME. VOR, short for VHF Omni-directional Radio Range, is a type of radio navigation system for aircraft. ...
GPS redirects here. ...
Radio navigation is the application of radio frequencies to determining a position on the earth. ...
NDB usage for aviation is standardized by ICAO Annex 10 which specifies that NDBs be operated on a frequency between 190 kHz and 1750 kHz[1] although normally all NDBs in North America operate between 190 kHz and 535 kHz[1]. Each NDB is identified by a one, two, or three-letter Morse code callsign. In Canada, some of the identifiers include numbers. North American NDBs are categorized by power output, with low power rated at less than 50 watts, medium from 50 W to 2,000 W and high being over 2,000 W.[2][3] The International Civil Aviation Organization (ICAO), an agency of the United Nations, codifies the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth. ...
This article is about the SI unit of frequency. ...
North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ...
1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting telegraphic information, using standardized sequences of short and long elements to represent the letters, numerals, punctuation and special characters of a message. ...
For other uses, see Watt (disambiguation). ...
Automatic Direction Finding equipment NDB navigation actually consists of two parts – the Automatic Direction Finding (or ADF) equipment on the aircraft that detects an NDB's signal, and the NDB transmitter itself. The ADF can also locate transmitters in the standard AM mediumwave broadcast band (530 kHz to 1700 kHz at 10 kHz increments in the Americas, 531 kHz to 1602 kHz at 9 kHz increments in the rest of the world). AM broadcasting is radio broadcasting using Amplitude Modulation. ...
Mediumwave radio transmissions serves as the most common band for broadcasting. ...
ADF equipment determines the direction to the NDB station relative to the aircraft. This may be displayed on a relative bearing indicator (RBI). This display looks like a compass card with a needle superimposed, except that the card is fixed with the 0 degree position corresponding to the centreline of the aircraft. In order to track toward an NDB with no wind the aircraft is flown so that the needle points to the 0 degree position, the aircraft will then fly directly to the NDB. Similarly, the aircraft will track directly away from the NDB if the needle is maintained on the 180 degree mark. With a crosswind, the needle must be maintained to the left or right of the 0 or 180 position by an amount corresponding to the drift due to the crosswind. A Relative bearing indicator shows the bearing of some source relative to a vehicle carrying a detector. ...
When tracking to or from an NDB it is also usual that the aircraft track on a specific bearing. To do this it is necessary to correlate the RBI reading with the compass heading. Having determined the drift, the aircraft must be flown so that the compass heading is the required bearing adjusted for drift at the same time as the RBI reading is 0 or 180 plus or minus drift as required. An NDB may also be used to locate a position along the aircraft track. When the needle reaches a RBI reading corresponding to the required bearing then the aircraft is at the position. However, using a separate RBI and compass this requires considerable mental calculation to determine the appropriate relative bearing.
To simplify this task a compass card is added to the RBI to form a 'Radio Magnetic Indicator', RMI. The ADF needle is then referenced immediately to the aircraft heading which reduces the necessity for mental calculation.
The principles of ADFs are not strictly limited to NDB usage; such systems are also used to detect the location of a broadcast signal for many other purposes, such as the location of emergency beacons.
Use of Non-Directional Beacons Download high resolution version (1024x768, 260 KB) A NDB of Beijing Capital Internation Airport. ...
Download high resolution version (1024x768, 260 KB) A NDB of Beijing Capital Internation Airport. ...
The Localizer station at Hanover/Langenhagen International Airport in Hanover, Germany. ...
Beijing Capital International Airport (Simplified Chinese: ; Traditional Chinese: ; Pinyin: ) (IATA: PEK, ICAO: ZBAA) is the main international airport that serves the capital city of Beijing, Peoples Republic of China. ...
The Localizer station at Hanover/Langenhagen International Airport in Hanover, Germany. ...
This article or section does not adequately cite its references or sources. ...
Airways A bearing is a line passing through the station that points in a specific direction, such as 270 degrees (due West). NDB bearings provide a charted, consistent method for defining paths aircraft can fly. In this fashion, NDBs can, like VORs, define 'airways' in the sky. Aircraft follow these pre-defined routes to complete a flight plan. Airways are numbered and standardized on charts; for example, J24 (juliet) is a high-altitude airway, and V119 (victor) is a low-altitude airway. Pilots follow these routes by tracking radials across various navigation stations, and turning at some. While most airways in the United States are based on VORs, NDB airways are common elsewhere, especially in the developing world and in lightly-populated areas of developed countries, like the Canadian Arctic, since they can have a long range and are much less expensive to operate than VORs. In navigation, a bearing is the clockwise angle between a reference direction (or a datum line) and the direction to an object. ...
For the movie, see Flightplan. ...
The red line indicates the 10°C isotherm in July, commonly used to define the Arctic region border Satellite image of the Arctic surface The Arctic is the region around the Earths North Pole, opposite the Antarctic region around the South Pole. ...
All standard airways are plotted on aeronautical charts, such as U.S. sectional charts. An aeronautical chart is a map designed to assist in navigation of aircraft, much as nautical charts do for watercraft, or a roadmap for drivers. ...
Fixes The ability to intercept fixes is a long-used application of NDBs. A fix is, literally, a point in the sky. These fixes are computed by drawing lines through navigation stations until they intercept, creating a triangle with the fix as one vertex: Plotting fixes in this manner allows a pilot to determine his rough horizontal location. This usage is important in situations where other navigational equipment, such as VORs with distance measuring equipment (DME), have failed. Image File history File links I drew this for the Non-directional Beacon article, it is a diagram of an airspace fix {PD} File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
D-VOR/DME ground station DME by itself Distance Measuring Equipment (DME) is a transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals. ...
Instrument Landing Systems NDBs are most commonly used as markers for an instrument landing system (ILS) approach and standard approaches. NDBs may designate the starting area for an ILS approach or a path to follow for a standard terminal arrival procedure, or STAR. In the United States, an NDB is often combined with the outer marker beacon in the ILS approach (called a Locator Outer Marker, or LOM); in Canada, low-powered NDBs have replaced marker beacons entirely. The Localizer station at Hanover/Langenhagen International Airport in Hanover, Germany. ...
In aviation, a Standard Terminal Arrival Route, also known as a Standard Terminal Arrival or simply a STAR, is a published procedure followed by aircraft on an IFR flight plan just before reaching a destination airport. ...
A Locator Outer Marker, or LOM, is a navigation aid used as part of an ILS instrument approach for aircraft in the United States. ...
Technical
 One of the wooden poles of NDB HDL at Plankstadt, Germany NDBs typically operate in the frequency range from 190 kHz to 535kHz (although they are allocated frequencies from 190 to 1750 kHz) and transmit a carrier modulated by either 400 or 1020 Hz. NDBs have a variety of owners, mostly governmental agencies and airport authorities. Image File history File links Size of this preview: 450 × 600 pixelsFull resolution (1536 × 2048 pixel, file size: 376 KB, MIME type: image/jpeg)Antenna mast of NDB HDL Plankstadt, Germany, photographed by myself on July 9th, 2006 Permission is granted to copy, distribute and/or modify this document under...
Image File history File links Size of this preview: 450 × 600 pixelsFull resolution (1536 × 2048 pixel, file size: 376 KB, MIME type: image/jpeg)Antenna mast of NDB HDL Plankstadt, Germany, photographed by myself on July 9th, 2006 Permission is granted to copy, distribute and/or modify this document under...
For other uses, see Frequency (disambiguation). ...
This article is about the SI unit of frequency. ...
In telecommunications, modulation is the process of varying a periodic waveform, i. ...
Other information transmitted by an NDB Apart from Morse Code Identity of either 400Hz or 1020Hz, the NDB may broadcast: - Airfield Terminal Information Service or ATIS
- Airfield Weather Information Service, or AWIS, or, in an emergency i.e. Air-Ground-Air Communication failure, an Air Traffic Controller using a Press-To-Talk (PTT) function, may modulate the carrier with voice. The pilot uses their ADF receiver to hear instructions from the Tower.
- Automated Weather Observation or AWOS
- Meteorological Information Broadcast or VOLMET
- Transcribed Weather Broadcast or TWEB
- PIP monitoring. If an NDB has a problem ie. Lower than normal power output i.e. half of its usual output power. Failure of mains, or standby transmitter is in operation, the NDB may be programmed to transmit an extra 'PIP' (a Morse dot), to alert pilots and others that the beacon may be unreliable for navigation.
Determining distance from an NDB Station To determine the distance in relation to a NDB station in nautical miles, you use this simple method: - Turn the aircraft so that the station is directly off one of the wingtips.
- Then fly that heading while timing how long it takes to cross a specific number of NDB bearing.
- Use the formula: Time to station = 60 x number of minutes flown / degrees of bearing change
- Now use your flight computer to calculate the distance the aircraft is from the station by determining a time*speed = distance calculation with a flight computer.
Common adverse effects Navigation using an ADF to track NDBs is subject to several common effects: - Night effect: radio waves can be reflected back by the ionosphere can cause fluctuations 30 to 60 nautical miles (approx. 54 to 108 km) from the transmitter, especially just before sunrise and just after sunset (more common on frequencies above 350 kHz)
- Terrain effect: high terrain like mountains and cliffs can reflect radio waves, giving erroneous readings; magnetic deposits can also cause erroneous readings
- Electrical effect: electrical storms, and sometimes also electrical interference (from a ground-based source or from a source within the aircraft) can cause the ADF needle to deflect towards the electrical source
- Shoreline effect: low-frequency radio waves will refract or bend near a shoreline, especially if they are close to parallel to it
- Bank effect: when the aircraft is banked, the needle reading will be offset
While pilots study these effects during initial training, trying to compensate for them in flight is very difficult; instead, pilots generally simply choose a heading that seems to average out any fluctuations.
Monitoring NDBs Besides their use in aircraft navigation, NDBs are also popular with long-distance radio enthusiasts ("DXers"). Because NDBs are generally low-power (usually 25 watts), they normally cannot be heard over long distances, but favorable conditions in the ionosphere can allow NDB signals to travel much farther than normal. Because of this, radio DXers interested in picking up distant signals enjoy listening to faraway NDBs. Also, since the band allocated to NDBs is free of broadcast stations and their associated interference, and because most NDBs do little more than transmit their Morse Code callsign, they are very easy to identify, making NDB monitoring a very entertaining niche within the DXing hobby. Relationship of the atmosphere and ionosphere The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation. ...
In North America, the NDB band is from 190 to 435 kHz and from 510 to 530 kHz. In Europe, there is a longwave broadcasting band from 150 to 280 kHz, so the European NDB band is from 280 kHz to 530 kHz with a gap between 495 and 505 kHz because 500 kHz is the international maritime distress (emergency) frequency. This article does not cite any references or sources. ...
Beginning in the early 20th century, the radio frequency of 500 kilohertz (kHz) has been an international (calling and) distress frequency for Morse code maritime communication. ...
The beacons that are between 510 kHz and 530 kHz can sometimes be heard on AM radios that can tune below the beginning of the AM broadcast band. (For example, the "HEH" beacon in Newark, Ohio at 524 kHz is within the bandwidth of most AM radios, and the "OH" beacon in Columbus, Ohio at 515 kHz can also be heard on some AM radios). But for the most part, reception of NDBs requires a shortwave radio which can receive frequencies below 530 kHz (the longwave band). Most so-called "shortwave" radios also include mediumwave and longwave, and they can usually receive all frequencies from 150 kHz to 30 MHz, which makes them ideal for listening to NDBs.
The best time to be able to hear NDBs that are very far away (which is called "DX") is the last three hours before sunrise. Also, reception of NDBs is best during the fall and winter because during the spring and summer, there is a very high level of atmospheric noise (static) on the longwave band.
See also It has been suggested that Air traffic control#Instrument Flight Rules (IFR) be merged into this article or section. ...
D-VOR (Doppler VOR) ground station, co-located with DME. VOR, short for VHF Omni-directional Radio Range, is a type of radio navigation system for aircraft. ...
D-VOR/DME ground station DME by itself Distance Measuring Equipment (DME) is a transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals. ...
GPS redirects here. ...
The Localizer station at Hanover/Langenhagen International Airport in Hanover, Germany. ...
GNSS - Global Navigation Satellite System In 1994 in a meeting of the ECAC, a satellite strategy was approved, with as targets: - firstly developing items for an European supplement on the current satellite systems, now called GNSS-1 - secondly designing and defining future satellite systems for civil use (called GNSS-2...
References - ^ a b U.S. FAA Aeronautical Information Manual Chapter 1. Setion 1. 1-1-2
- ^ Florida International University/NASA ALLSTAR Network
- ^ Canada Flight Supplement
- International Civil Aviation Organization (2000). Annex 10 — Aeronautical Telecommunications, Vol. I (Radio Navigation Aids) (5th ed.).
- U.S. Federal Aviation Administration (2004). Aeronautical Information Manual, § 1-1-2.[1]
This article is about the American space agency. ...
The Canada Flight Supplement with its current blue cover since Nav Canada took over publication. ...
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