direction finder


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direction finder,

electronic device used to determine the position of a ship or aircraft. In a simple direction finder a radio receiver is equipped with a revolving directional antenna. The antenna receives the strongest radio signal when it is pointing directly at a transmitter. By determining the direction of two land-based transmitters, a navigator may plot his position by triangulation. Direction finders have been replaced in many applications with more accurate systems, such as radarradar,
system or technique for detecting the position, movement, and nature of a remote object by means of radio waves reflected from its surface. Although most radar units use microwave frequencies, the principle of radar is not confined to any particular frequency range.
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 and satellite navigation systems (see satellite, artificialsatellite, artificial,
object constructed by humans and placed in orbit around the earth or other celestial body (see also space probe). The satellite is lifted from the earth's surface by a rocket and, once placed in orbit, maintains its motion without further rocket propulsion.
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).

Direction Finder

 

an instrument used in marine and air navigation to determine the direction in degrees to external reference points such as coastal or floating objects, heavenly bodies, and so on.

direction finder

[də′rek·shən ‚fīnd·ər]
(navigation)

direction finder (DF)

A radio receiver equipped with a directional sensing antenna used to take bearings on a radio transmitter. Specialized radio direction finders are used in aircraft as air navigation aids. Others are ground based, primarily to obtain a “fix” on a pilot requesting orientation assistance or to locate downed aircraft. UDFs (ultrahigh frequency direction finders) receive signals in the ultrahigh frequency radio broadcast band; VDFs in the very high frequency band; and UVDFs (UHD/VHD direction finder) in both bands. See automatic direction finder.
References in periodicals archive ?
The light-cone direction finder improves the localisation of multiple radio signals and the rejection of spurious signals in a complex electromagnetic environment and is significantly superior to current systems.
The direction finder enhances several radio signal localisation and rejection of spurious signals within a complex electromagnetic environment.
Final approval by the Korea Communications Commission came earlier this month with the granting of a license to Apple to offer so-called location-based services, which include functions such as maps and direction finders that are available on the iPhone.
Radio Direction Finders (RDFs) were once the primary method for ships and aircraft to navigate; most of us have seen pictures of World War II airplanes with the familiar loop antenna projecting out of the fuselage, ready to direct the fighter or bomber home after a mission.
Voice-Enabled Mobile Devices Two forces are driving speech technology in the car: Automobile manufacturers are embedding speech in the dashboard, and independent vendors provide car add-ons such as cell-phone holders and interactive direction finders.
The system consists of three primary components: transmitters, receivers and direction finders.
The 11-year-old posts will be uprooted this month and 16 metal direction finders put in their place as part of a multi-million pound Stratford initiative.
Other equipment that Rockwell Collins will be providing includes: Communication Management Units, Satellite Communications Systems, VHF and HF transceivers, VHF Omnidirectional Radio, Distance Measuring Equipment, Automatic Direction Finders, Multi Mode Receivers, Mode S Transponders, Cockpit Voice Recorders, Flight Data Recorders, Emergency Locator Transmitters, Flight Deck Printers and the Data Management Units.
Expert Wiley covers the latest technologies, first defining electronic intelligence and giving its capabilities and limitations and then covering ELINT implications of range equations and radar constraints, characteristics of ELINT interception systems, the probability of intercept, antennas and direction finders, emitter locations, estimation of power at the transmitter, antenna parameters, "low probability of intercept" (LPI) radar and ELINT, antenna scan analysis, intrapulse analysis, pulse repetition interval analysis, deinterleaving pulse trains, measurement and analysis of carrier frequency, determining ELINT parameter limits, and working with ELINT data files.
In addition to codebreaking, B-Dienst operated a network of direction finders that fixed the approximate locations of radio transmissions in the Atlantic.
It seemed to me that Wales had some pretty good direction finders of their own.
They will be equipped with forward-looking infrared and high-resolution digital day/night-vision cameras, satellite communication and navigation systems, digital map devices, Tetra digital radios, collision warning systems, tactical direction finders, digital flight management systems and GSM telephones.

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