Low frequency or low freq or LF refers to radio frequencies (RF) in the range of 30 kHz–300 kHz. In Europe, and parts of Northern Africa and of Asia, part of the LF spectrum is used for AM broadcasting as the longwave band. In the western hemisphere, its main use is for aircraft beacon, navigation (LORAN), information, and weather systems. Time signal stations MSF, DCF77, JJY and WWVB are found in this band. Also known as the kilometer band or ki...
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Low frequency or low freq or LF refers to radio frequencies (RF) in the range of 30 kHz–300 kHz. In Europe, and parts of Northern Africa and of Asia, part of the LF spectrum is used for AM broadcasting as the longwave band. In the western hemisphere, its main use is for aircraft beacon, navigation (LORAN), information, and weather systems. Time signal stations MSF, DCF77, JJY and WWVB are found in this band. Also known as the kilometer band or kilometer wave as the wavelengths range from ten to one kilometers.
Low frequency radio signals can follow the curvature of the earth. Radio waves reaching the receiver by this route are called ground waves. Their strength is not reduced by absorption as much as in higher frequencies. Ground wave can cover an area with a radius of 2000 km about the transmitting antenna.
Propagation by reflection (the actual mechanism is one of refraction) from the ionosphere is also possible. The reflection can take place at the D layer (50–90 km) or the E layer...
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