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It is possible to also get a bad picture if the signal strength of the TV transmitter is too high. An attenuator inserted in the antenna lead-in wire may be used if the television receiver displays signs of overload in the RF front end. Strong out-of-band signals may also affect television reception and may require band-pass filters to reduce ...
The antennas contained in mobile phones, including smartphones, emit radiofrequency (RF) radiation (non-ionizing "radio waves" such as microwaves); the parts of the head or body nearest to the antenna can absorb this energy and convert it to heat or to synchronised molecular vibrations (the term 'heat', properly applies only to disordered molecular motion).
The field strength of electromagnetic radiation is measured in volts per meter (V/m). [2] The most common health hazard of radiation is sunburn, which causes between approximately 100,000 and 1 million new skin cancers annually in the United States. [3] [4]
In telecommunications, [1] particularly in radio frequency engineering, signal strength refers to the transmitter power output as received by a reference antenna at a distance from the transmitting antenna. High-powered transmissions, such as those used in broadcasting, are expressed in dB-millivolts per metre (dBmV/m).
Outdoor antennas provide up to a 15 dB gain in signal strength and 15-20 dB greater rejection of ghost signals in analog TV. [6] Combined with a signal increase of 14 dB due to height and 11 dB due to lack of attenuating building walls, an outdoor antenna can result in a signal strength increase of up to 40 dB at the TV receiver. [6] Outdoor ...
HDTV antenna amplifiers counteract poor picture and sound on local TV broadcasts caused by a degraded cable signal, which may occur when you use an extra-long run of cable or a line that runs ...
In telecommunications, the (digital) cliff effect or brick-wall effect is a sudden loss of digital signal reception.Unlike analog signals, which gradually fade when signal strength decreases or electromagnetic interference or multipath increases, a digital signal provides data which is either perfect or non-existent at the receiving end.
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 ...