pls send the ppt of seminar fm direction finder

A radio address locator (RDF) is a device for finding direction, or leading, to a radio source. The act of measuring the direction is known as radio direction detection or, sometimes, simply, direction finding (DF). Using two or more measurements from different locations, the location of an unknown transmitter can be determined; Alternatively, by using two or more measurements of known transmitters, the location of a vehicle can be determined. RDF is widely used as a radionavigation system, especially with ships and airplanes.

RDF systems can be used with any radio source, although the size of the receiving antennas is a function of the wavelength of the signal; Very long wavelengths require very large antennas, and are generally used only in ground-based systems. These wavelengths are however very useful for sea navigation, as they can travel very long distances and "over the horizon", which is valuable for ships when the line of sight may be only a few tens of kilometers. For aerial use, where the horizon can be extended to hundreds of kilometers, higher frequencies can be used, allowing the use of much smaller antennas. An automatic address finder, often able to be tuned to commercial AM radio transmitters, is a feature of almost all modern aircraft.

FM Direction Finder has extensive applications such as boat navigation, aircraft, missiles, radar, tracking satellites and other astronomical radio sources. In the field of communications, some requirements might be to cross the intensity, direction and positioning of the transmitters used in a cluster of a GSM network. It can be used to locate radio sources that temporarily block any communication network. It is also widely used in spectrum management to verify the growth of transmitters in specific regions such as radio astronomical observatories, etc. In the past, several direction finders have been built. Different techniques have been used in different instruments. These instruments could be broadly classified into vector or scalar radio direction locators. Vector types require both amplitude and phase information of the electromagnetic field at the antenna aperture, while scalar types require only amplitude information. In general, these instruments employ these measurements at various points in the three-dimensional space.