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  2. Radio frequency - Wikipedia

    en.wikipedia.org/wiki/Radio_frequency

    Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in ...

  3. Fresnel zone - Wikipedia

    en.wikipedia.org/wiki/Fresnel_zone

    This means objects which are clear of the line of sight path will still potentially block parts of the signal. To maximize signal strength, one needs to minimize the effect of obstruction loss by removing obstacles from both the direct radio frequency line of sight (RF LoS) line and also the area around it within the primary Fresnel zone. The ...

  4. Radio repeater - Wikipedia

    en.wikipedia.org/wiki/Radio_repeater

    A radio repeater is a combination of a radio receiver and a radio transmitter that receives a signal and retransmits it, so that two-way radio signals can cover longer distances. A repeater sited at a high elevation can allow two mobile stations, otherwise out of line-of-sight propagation range of each other, to communicate. [ 1 ]

  5. Radio wave - Wikipedia

    en.wikipedia.org/wiki/Radio_wave

    The radio spectrum is divided into a number of radio bands on the basis of frequency, allocated to different uses. Higher-frequency, shorter-wavelength radio waves are called microwaves. Diagram of the electric fields (E) and magnetic fields (H) of radio waves emitted by a monopole radio transmitting antenna (small dark vertical line in the ...

  6. Radiolocation - Wikipedia

    en.wikipedia.org/wiki/Radiolocation

    Radiolocation, also known as radiolocating or radiopositioning, is the process of finding the location of something through the use of radio waves.It generally refers to passive, particularly radar—as well as detecting buried cables, water mains, and other public utilities.

  7. Radio receiver - Wikipedia

    en.wikipedia.org/wiki/Radio_receiver

    In the simplest type of radio receiver, called a tuned radio frequency (TRF) receiver, the three functions above are performed consecutively: [9] (1) the mix of radio signals from the antenna is filtered to extract the signal of the desired transmitter; (2) this oscillating voltage is sent through a radio frequency (RF) amplifier to increase ...

  8. Skip distance - Wikipedia

    en.wikipedia.org/wiki/Skip_distance

    A skip distance is the distance a radio wave travels, usually including a hop in the ionosphere.A skip distance is a distance on the Earth's surface between the two points where radio waves from a transmitter, refracted downwards by different layers of the ionosphere, fall.

  9. Antenna (radio) - Wikipedia

    en.wikipedia.org/wiki/Antenna_(radio)

    [1] [2] It is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. [1] In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio