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Doppler radio direction finding, also known as Doppler DF, is a radio direction-finding method that generates accurate bearing information with minimal electronics. It is best suited to applications in VHF and UHF frequencies and takes only a short time to indicate a direction. This makes it suitable for measuring the location of the vast ...
If so, one of the three jammers would put out a warbling tone on that frequency, making verbal instructions impossible. Carried by 101 Sqn Lancasters based at Ludford Magna and from March 1945 by 462 Sqn RAAF, operating from RAF Foulsham. [4] These aircraft carried an 8th crew member. [5]
The basic concept used a loop antenna, in its most basic form simply a circular loop of wire with a circumference decided by the frequency range of the signals to be detected. When the loop is aligned at right angles to the signal, the signal in the two halves of the loop cancels out, producing a sudden drop in output known as a "null".
A portable, battery operated GT-302 Accumatic automatic direction finder for marine use. Radio direction finding, radio direction finder, or RDF, was once the primary aviation navigational aid. (Range and Direction Finding was the abbreviation used to describe the predecessor to radar. [2])
Ultra high frequency (UHF) is the ITU designation [1] [2] for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (one decimeter).
The simplest klystron tube is the two-cavity klystron. In this tube there are two microwave cavity resonators, the "catcher" and the "buncher". When used as an amplifier, the weak microwave signal to be amplified is applied to the buncher cavity through a coaxial cable or waveguide, and the amplified signal is extracted from the catcher cavity.
Coincidence rangefinders were important elements of fire control systems for long-range naval guns and land-based coastal artillery circa 1890–1960. They were also used in rangefinder cameras . A stereoscopic rangefinder looks similar, but has two eyepieces and uses a different principle, based on binocular vision .
Repeaters are found mainly in the VHF 6-meter (50–54 MHz), 2-meter (144–148 MHz), 1.25-meter band (1 1 ⁄ 4 meters) (220–225 MHz) and the UHF 70 centimeter (420–450 MHz) bands, but can be used on almost any frequency pair above 28 MHz. In some areas, 33 centimeters (902–928 MHz) and 23 centimeters (1.24–1.3 GHz) are also used for ...