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  2. Leaky feeder - Wikipedia

    en.wikipedia.org/wiki/Leaky_feeder

    Diagram of leaky feeder cable. A leaky feeder is a communications system used in underground mines and inside tunnels. [1] Manufacturers and cabling professionals use the term "radiating cable" [2] [3] [better source needed] [4] as this implies that the cable is designed to radiate: something that a typical coaxial cable is generally not intended to do.

  3. Antenna feed - Wikipedia

    en.wikipedia.org/wiki/Antenna_feed

    In a radio antenna, the feed line (feedline), or feeder, is the cable or other transmission line that connects the antenna with the radio transmitter or receiver.In a transmitting antenna, it feeds the radio frequency (RF) current from the transmitter to the antenna, where the energy in the current is radiated as radio waves.

  4. Radiation-absorbent material - Wikipedia

    en.wikipedia.org/wiki/Radiation-absorbent_material

    For low-frequency damping in military applications, this distance is often 60 cm (24 in), while high-frequency panels are as short as 7.5 to 10 cm (3 to 4 in). An example of a high-frequency application would be the police radar (speed-measuring radar K and Ka band), the pyramids would have a dimension around 10 cm (4 in) long and a 5 cm × 5 ...

  5. Fractal antenna - Wikipedia

    en.wikipedia.org/wiki/Fractal_antenna

    A fractal antenna is an antenna that uses a fractal, self-similar design to maximize the effective length, or increase the perimeter (on inside sections or the outer structure), of material that can receive or transmit electromagnetic radiation within a given total surface area or volume.

  6. Path loss - Wikipedia

    en.wikipedia.org/wiki/Path_loss

    Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space (which usually takes the shape of an ever-increasing sphere), absorption losses (sometimes called penetration losses), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radiowave front is obstructed by an opaque ...

  7. Corona discharge - Wikipedia

    en.wikipedia.org/wiki/Corona_discharge

    Coronas can generate audible and radio-frequency noise, particularly near electric power transmission lines. Therefore, power transmission equipment is designed to minimize the formation of corona discharge. Corona discharge is generally undesirable in: Electric power transmission, where it causes: Power loss; Audible noise

  8. Critical band - Wikipedia

    en.wikipedia.org/wiki/Critical_band

    The auditory filter of an impaired ear is flatter and broader compared to a normal ear. This is because the frequency selectivity and the tuning of the basilar membrane is reduced as the outer hair cells are damaged. When only the outer hair cells are damaged the filter is broader on the low frequency side.

  9. 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 ...