Reradiation
Encyclopedia
In telecommunication
, the term reradiation has the following meanings:
Near-field
effects of an AM antenna
may extend out two miles (3 km) or more. Cellular
and Microwave
towers within this radius can reflect the AM signal out at a different frequency
. This process results in interfering frequencies called reradiation.
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
, the term reradiation has the following meanings:
- Electromagnetic radiationElectromagnetic radiationElectromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...
, at the same or different wavelengths, i.e., frequencies, of energy received from an incident wave. - Undesirable radiation of signals locally generated in a radioRadioRadio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
receiver. This type of radiation might cause interferenceInterference (communication)In communications and electronics, especially in telecommunications, interference is anything which alters, modifies, or disrupts a signal as it travels along a channel between a source and a receiver. The term typically refers to the addition of unwanted signals to a useful signal...
or reveal the location of the device.
Near-field
Near and far field
The near field and far field and the transition zone are regions of the electromagnetic radiation field that emanates from a transmitting antenna, or as a result of radiation scattering off an object...
effects of an AM antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
may extend out two miles (3 km) or more. Cellular
Cellular
Cellular may refer to:*Cellular automaton, a model in discrete mathematics*Cellular , a 2004 movie*Cellular frequencies, assigned to networks operating in cellular RF bands*Cellular manufacturing...
and Microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
towers within this radius can reflect the AM signal out at a different frequency
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
. This process results in interfering frequencies called reradiation.