HOME TheInfoList.com
Providing Lists of Related Topics to Help You Find Great Stuff
[::MainTopicLength::#1500] [::ListTopicLength::#1000] [::ListLength::#15] [::ListAdRepeat::#3]

Cellular Network
A CELLULAR NETWORK or MOBILE NETWORK is a communication network where the last link is wireless. The network is distributed over land areas called cells, each served by at least one fixed-location transceiver , but more normally three cell sites or base stations . These base stations provide the cell with the network coverage which can be used for transmission of voice, data and others. A cell typically uses a different set of frequencies from neighboring cells, to avoid interference and provide guaranteed service quality within each cell. When joined together these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones , pagers , etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission
[...More...]

"Cellular Network" on:
Wikipedia
Google
Yahoo

picture info

Whip Antenna
A WHIP ANTENNA is an antenna consisting of a straight flexible wire or rod. The bottom end of the whip is connected to the radio receiver or transmitter . The antenna is designed to be flexible so that it does not break easily,and the name is derived from the whip -like motion that it exhibits when disturbed. Whip antennas for portable radios are often made of a series of interlocking telescoping metal tubes, so they can be retracted when not in use. Longer ones, made for mounting on vehicles and structures, are made of a flexible fiberglass rod around a wire core and can be up to 35 ft (10 m) long. The length of the whip antenna is determined by the wavelength of the radio waves it is used with. The most common type is the quarter-wave whip, which is approximately one-quarter of a wavelength long. Whips are the most common type of monopole antenna , and are used in the HF , VHF and UHF radio bands
[...More...]

"Whip Antenna" on:
Wikipedia
Google
Yahoo

Antenna Gain
In electromagnetics , an antenna's POWER GAIN or simply GAIN is a key performance number which combines the antenna 's directivity and electrical efficiency . In a transmitting antenna, the gain describes how well the antenna converts input power into radio waves headed in a specified direction. In a receiving antenna, the gain describes how well the antenna converts radio waves arriving from a specified direction into electrical power. When no direction is specified, "gain" is understood to refer to the peak value of the gain, the gain in the direction of the antenna's main lobe . A plot of the gain as a function of direction is called the radiation pattern . Antenna gain is usually defined as the ratio of the power produced by the antenna from a far-field source on the antenna's beam axis to the power produced by a hypothetical lossless isotropic antenna , which is equally sensitive to signals from all directions
[...More...]

"Antenna Gain" on:
Wikipedia
Google
Yahoo

ITU Radio Regulations
The ITU RADIO REGULATIONS (short: RR) regulates on law of nations scale radiocommunication services and the utilisation of radio frequencies. It is the supplementation to the Constitution and Convention of the International Telecommunication Union
International Telecommunication Union
(ITU Constitution and Convention). In line to the ITU Constitution and Convention and the ITU International Telecommunication Regulations (ITR), this ITU Radio Regulations belong to the basic documents of the International Telecommunication Union
International Telecommunication Union
. The ITU Radio Regulations comprise and regulate the part of the allocated electromagnetic spectrum (also: radio frequency spectrum ) from 9 kHz to 275 GHz
[...More...]

"ITU Radio Regulations" on:
Wikipedia
Google
Yahoo

Antenna Boresight
In telecommunications and radar engineering, ANTENNA BORESIGHT is the axis of maximum gain (maximum radiated power) of a directional antenna . For most antennas the boresight is the axis of symmetry of the antenna. For example, for axial-fed dish antennas , the antenna boresight is the axis of symmetry of the parabolic dish, and the antenna radiation pattern (the main lobe) is symmetrical about the boresight axis. Most antennas boresight axis is fixed by their shape and cannot be changed. However phased array antennas can electronically steer the beam, changing the angle of the boresight by shifting the relative phase of the radio waves emitted by different antenna elements, and even radiate beams in multiple directions (multiple boresights). The term boresight came from high-gain antennas such as parabolic dishes, which produce narrow, pencil-shaped beams which are difficult to aim accurately at a distant receiving antenna
[...More...]

"Antenna Boresight" on:
Wikipedia
Google
Yahoo

Ground Plane
In electrical engineering , a GROUND PLANE is an electrically conductive surface, usually connected to electrical ground . The term has two different meanings in separate areas of electrical engineering. In antenna theory, a ground plane is a conducting surface large in comparison to the wavelength , such as the Earth, which is connected to the transmitter 's ground wire and serves as a reflecting surface for radio waves . In printed circuit boards , a ground plane is a large area of copper foil on the board which is connected to the power supply ground terminal and serves as a return path for current from different components on the board. CONTENTS * 1 Radio antenna theory * 2 Printed circuit boards * 3 See also * 4 References RADIO ANTENNA THEORYIn telecommunication , a ground plane is a flat or nearly flat horizontal conducting surface that serves as part of an antenna , to reflect the radio waves from the other antenna elements
[...More...]

"Ground Plane" on:
Wikipedia
Google
Yahoo

Main Lobe
In a radio antenna\'s radiation pattern , the MAIN LOBE, or MAIN BEAM is the lobe containing the maximum power . This is the lobe that exhibits the greatest field strength . The radiation pattern of most antennas shows a pattern of "lobes" at various angles, directions where the radiated signal strength reaches a maximum, separated by "nulls ", angles at which the radiation falls to zero. In a directional antenna in which the objective is to emit the radio waves in one direction, the lobe in that direction is designed to have higher field strength than the others, so on a graph of the radiation pattern it appears biggest; this is the main lobe. The other lobes are called "sidelobes ", and usually represent unwanted radiation in undesired directions. The sidelobe in the opposite direction from the main lobe is called the "backlobe"
[...More...]

"Main Lobe" on:
Wikipedia
Google
Yahoo

Focal Cloud
A FOCAL CLOUD is the collection of focal points of an imperfect lens or parabolic reflector whether optical , electrostatic or electromagnetic. This includes parabolic antennas and lens-type reflective antennas of all kinds. The effect is analogous to the circle of confusion in photography. In a perfect lens or parabolic reflector, rays parallel to the device's axis striking the lens or reflector all pass through a single point, the focal point . In an imperfectly constructed lens or reflector, rays passing through different parts of the element do not converge to a single point but have different focal points. The set of these focal points forms a region called the focal cloud. The diameter of the focal cloud determines the maximum resolution of the optical system. Lens-reflector artifacts, geometry and other imperfections determine the actual diameter of the focal cloud
[...More...]

"Focal Cloud" on:
Wikipedia
Google
Yahoo

Wireless Electronic Devices And Health
The World Health Organization (WHO) has acknowledged the "anxiety and speculation" regarding electromagnetic fields (EMFs) and their alleged effects on public health. In response to public concern, the WHO established the International EMF Project in 1996 to assess the scientific evidence of possible health effects of EMF in the frequency range from 0 to 300 GHz. They have stated that although extensive research has been conducted into possible health effects of exposure to many parts of the frequency spectrum, all reviews conducted so far have indicated that, as long as exposures are below the limits recommended in the ICNIRP (1998) EMF guidelines, which cover the full frequency range from 0–300 GHz, such exposures do not produce any known adverse health effect. Stronger or more frequent exposures to EMF can be unhealthy, and in fact serve as the basis for electromagnetic weaponry
[...More...]

"Wireless Electronic Devices And Health" on:
Wikipedia
Google
Yahoo

picture info

Radio
RADIO is the technology of using radio waves to carry information, such as sound, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude , frequency , phase , or pulse width . When radio waves strike an electrical conductor , the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form. Radio
Radio
systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation ). Radio
Radio
systems also need an antenna to convert electric currents into radio waves , and radio waves into an electric current. An antenna can be used for both transmitting and receiving
[...More...]

"Radio" on:
Wikipedia
Google
Yahoo

Radio Masts And Towers
RADIO MASTS AND TOWERS are, typically, tall structures designed to support antennas (also known as aerials) for telecommunications and broadcasting , including television . There are two main types: guyed and self-supporting structures. They are among the tallest man-made structures. Masts are often named after the broadcasting organizations that originally built them or currently use them. In the case of a mast radiator or radiating tower, the whole mast or tower is itself the transmitting antenna
[...More...]

"Radio Masts And Towers" on:
Wikipedia
Google
Yahoo

Mobile Phone Radiation And Health
The effect of MOBILE PHONE RADIATION ON HUMAN HEALTH is a subject of interest and study worldwide, as a result of the enormous increase in mobile phone usage throughout the world. As of 2015 , there were 7.4 billion subscriptions worldwide, though the actual number of users is lower as many users own more than one mobile phone. Mobile phones use electromagnetic radiation in the microwave range (450–2100 MHz). Other digital wireless systems , such as data communication networks, produce similar radiation. Mobile phone use does not increase the risk of getting brain cancer or other head tumors
[...More...]

"Mobile Phone Radiation And Health" on:
Wikipedia
Google
Yahoo

picture info

Near And Far Field
The NEAR FIELD and FAR FIELD are regions of the electromagnetic field around an object, such as a transmitting antenna , or the result of radiation scattering off an object. Non-radiative 'near-field' behaviours of electromagnetic fields dominate close to the antenna or scattering object, while electromagnetic radiation 'far-field' behaviours dominate at greater distances. Far-field E and B field strength decreases inversely with distance from the source, resulting in an inverse-square law for the radiated power intensity of electromagnetic radiation . By contrast, near-field E and B strength decrease more rapidly with distance (with inverse-distance squared or cubed), resulting in relative lack of near-field effects within a few wavelengths of the radiator
[...More...]

"Near And Far Field" on:
Wikipedia
Google
Yahoo

picture info

Vertical Plane
VERTICAL PLANE is used in radio to plot an antenna's relative field strength perpendicular to the ground (which directly affects a station's coverage area) on a polar graph . Normally the maximum of 1.000 or 0 dB is at the side (unless there is beam tilt ), which is labeled 0°, to 90° at the top and −90° at the bottom. Other field strengths are expressed as a decimal less than 1.000, a percentage less than 100%, or decibels less than 0 dB. Most broadcast antennas use either line-of-sight or ground wave propagation (a slight refraction towards the ground) to reach their nearby listeners, and thus want a low angle in the vertical plane. Short wave transmitters want a somewhat higher elevation angle in the vertical plane to encourage skywave propagation, which would refract or reflect radio waves off the ionosphere and back to the ground at a great distance from the transmitter
[...More...]

"Vertical Plane" on:
Wikipedia
Google
Yahoo

Antenna Equivalent Radius
The EQUIVALENT RADIUS of an antenna conductor is defined as: r e = exp { 1 L 2 ln x y d x d y } {displaystyle r_{e}=exp left{{1 over L^{2}}oint _{ell }oint _{ell }ln vert {boldsymbol {x}}-{boldsymbol {y}}vert ;dx;dyright}} where {displaystyle scriptstyle ell } denotes the conductor's circumference , L {displaystyle scriptstyle {L}} is the length of the circumference, x {displaystyle scriptstyle {boldsymbol {x}}} and y {displaystyle scriptstyle {boldsymbol {y}}} are vectors locating points along the circumference, and d x {displaystyle scriptstyle {dx}} and d y {displaystyle scriptstyle {dy}} are differentials segments along it
[...More...]

"Antenna Equivalent Radius" on:
Wikipedia
Google
Yahoo

Antenna Factor
In electromagnetics , the ANTENNA FACTOR is defined as the ratio of the electric field strength to the voltage V (units: V or µV) induced across the terminals of an antenna . The voltage measured at the output terminals of an antenna is not the actual field intensity due to actual antenna gain , aperture characteristics , and loading effects
[...More...]

"Antenna Factor" on:
Wikipedia
Google
Yahoo
.