NationMaster - Encyclopedia: Cellular repeater

A cellular repeater, cell phone repeater, or wireless cellular signal booster, called a bi-directional amplifier (BDA) in the wireless telecommunications industry, is a device used to boost the cell phone reception to the local area by the usage of a reception antenna, a signal amplifier and an internal rebroadcast antenna. These are similar to the cellular broadcast towers used to broadcast by the network providers, but are much smaller, usually intended for use by one building. Modern cellular repeater amplifiers work by rebroadcasting cellular signals inside the building. The systems usually use an external, directional antenna to collect the best cellular signal, which is then transmitted to an amplifier unit which amplifies the signal, and retransmits it locally, providing significantly improved signal strength. The more advanced models often also allow multiple cell phones to use the same repeater at the same time, so are suitable for commercial as well as home use. Image File history File links Download high resolution version (600x630, 66 KB) Summary Description: A typical compact cellular repeater with directional antenna Source: Clear Voice Images, courtesy of http://www. ... Image File history File links Download high resolution version (600x630, 66 KB) Summary Description: A typical compact cellular repeater with directional antenna Source: Clear Voice Images, courtesy of http://www. ... Clear Voice is a registered trademark of Telecom Technologies (USA) LLC for their range of home and office cellular repeaters (also known as cell boosters or bi-directional amplifiers). ... Look up boost in Wiktionary, the free dictionary. ... Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna or aerial is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. ... Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ... Log-periodic dipole array A directional antenna is an antenna which transmits or receives maximum power in a particular direction. ... Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ... In telecommunications, and particularly in radio, signal strength is the measure of how strongly a transmitted signal is being received, measured, or predicted, at a reference point that is a significant distance from the transmitting antenna. ... Cellular redirects here. ...

The market for cellular repeaters is expected to grow rapidly in the US over the coming years. This is due to the combination of the poor network coverage in some areas, and the large scale departure from the land-line system. By 2007 the CTIA (Cellular Telecommunications & Internet Association) predict that 30% of phone users in the US will be mobile only - more than 60 million lines. This combined with the low population density (compared with Europe and Japan); the fact that only 41% of the US population is urban; the low cell site density; and the fact that the cell network is split into over ten major providers means that many people will have to use some method to improve their home signal. It has been suggested that Rain fade be merged into this article or section. ... CTIA can stand for: The Color Television Interface Adapter for Atari computers Cellular Telecommunications & Internet Association This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... A cellular radio network is a radio network made up of a number of radio cells (or just cells) each served by a fixed transmitter, normally known as a base station. ...

Other advantages of cellular repeaters include an increase in the cell phone's battery life and a lower level of radiation emitted by the handset - both caused by the lower power required to broadcast the signal to the local bi-directional amplifier, due to its proximity to the phone.

1 Typical components
2 Reasons for weak signal
3 Different operating frequencies
4 See also
5 External links

Typical components

External directional antenna

Although some of the less expensive models do not include an external directional antenna they are crucial to providing significant signal strength gain. This is because the antenna can be oriented and located outside to provide the best possible signal, usually aligned with the nearest cell tower. Generally speaking the larger the external antenna the better the signal - although even a small, correctly oriented external antenna should provide better signal than the internal antenna on any cell phone. These can either be fitted by professionals or will include a signal strength monitor for easy alignment. Log-periodic dipole array A directional antenna is an antenna which transmits or receives maximum power in a particular direction. ... Log-periodic dipole array A directional antenna is an antenna which transmits or receives maximum power in a particular direction. ... Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ...

Internal rebroadcast antenna

The better systems will generally include an internal monopole antenna (although the type of antenna is far from standardised) for rebroadcasting the signal internally - the advantage of using a monopole antenna is that the signal will be equally distributed in all directions (subject, of course, to attenuation from obstacles). Due to the fact that all radio antennas are intrinsically polarized, the cell phones will perform best when their antennas are oriented parallel to the booster's antenna - although within reasonable proximity the booster's signal will be strong enough that the orientation of the cell phone's antenna will not make a significant difference in usability. Wikipedia does not have an article with this exact name. ... This article treats polarization in electrodynamics. ... Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ...

Signal amplifier

All modern models will include a signal amplifier. Even the cheaper home-use models now provide around 30dB gain and many of the more expensive models provide over 50dB. However, it should be noted that since the decibel scale is measured on a logarithmic scale a 30dB gain represents a one thousand fold signal power increase - meaning the total amplification of a repeater with greater than around 50dB is likely to be useless without a good, well aligned antenna. This is due to the difficulty of filtering the correct signal out from the background noise, which will be amplified equally, and the limiting maximum signal power of the amplifier (typically from around 5 dBm or 3.2 mW). The power gain is calculated by the following equation: Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ... Generally, an amplifier is any device that will use a small amount of energy to control a larger amount of energy. ... In electronics, gain is usually taken as the mean ratio of the signal output of a system to the signal input of the system. ... The decibel (dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power) relative to a specified or implied reference level. ... A logarithmic scale is a scale of measurement that uses the logarithm of a physical quantity instead of the quantity itself. ... The correct title of this article is . ...

$quad P_mathrm{dB} = 10 log_{10} left(frac{P}{P_0} right)$

Reasons for weak signal

Rural areas

In many rural areas the housing density is too low to make construction of a new base station commercially viable. In these cases it is unlikely that the service provider will do anything to improve reception, due to the high cost of erecting a new tower. As a result, the only way to obtain strong cell phone signal in these areas is usually to install a home cellular repeater. In flat rural areas the signal is unlikely to suffer from multipath interference, so will just be heavily attenuated by the distance. In these cases the installation of a cellular repeater will generally massively increase signal strength just due to the amplifier, even a great distance from the broadcast towers. The term base station can be used in the context of land surveying, wireless computer networking, and wireless communications. ... Multipath interference is a phenomenon in the physics of waves whereby a wave from a source travels to a detector via two or more paths and, under the right condition, the two (or more) components of the wave interfere. ...

Building construction material

Some construction materials very rapidly attenuate cell phone signal strength. Older buildings, such as churches, which use lead in their roofing material will very effectively block any signal. Any building which has a significant thickness of concrete or amount of metal used in its production will attenuate the signal somewhat. Some solid foam insulation used for roofs or exterior wall has foil backing, which can reduce transmittance. Some materials have peaks in their absorption spectra which massively decrease signal strength. Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ... Electromagnetic radiation may be characterised by its wavelength. ...

Building size

Large buildings, such as warehouses, hospitals and factories, often have no cellular reception further than a few meters from the outside wall. Low signal strength is also often the case in underground areas such as basements and in shops and restaurants located towards the centre of shopping malls. This is caused by both the fact that the signal is attenuated heavily as it enters the building and the interference as the signal is reflected by the objects inside the building. For this reason in these cases an external antenna is usually desirable. McArthur Glen Designer Outlet, Swindon, England, a shopping mall built within a disused railway engine works. ...

Multipath interference

Even in urban areas which usually have strong cellular signals throughout, there are often dead zones caused by destructive interference of waves which have taken different paths (caused by the signal bouncing off buildings etc.). These usually have an area of a few blocks and will usually only affect one of the two frequency ranges used by cell phones. This is because the different wavelengths of the different frequencies interfere destructively at different points. Directional antennae are very helpful at overcoming this since they can be placed at points of constructive interference and aligned so as not to receive the destructive signal. See Multipath interference for more. This page is about the oceanic phenomenon; see The Dead Zone for the novel by Stephen King. ... Interference of two circular waves - Wavelength (decreasing bottom to top) and Wave centers distance (increasing to the right). ... Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ... Log-periodic dipole array A directional antenna is an antenna which transmits or receives maximum power in a particular direction. ... Interference of two circular waves - Wavelength (decreasing bottom to top) and Wave centers distance (increasing to the right). ... Multipath interference is a phenomenon in the physics of waves whereby a wave from a source travels to a detector via two or more paths and, under the right condition, the two (or more) components of the wave interfere. ...

Diffraction and general attenuation

The longer wavelengths have the advantage of being able to diffract to a greater degree so are less reliant on line of sight to obtain a good signal, but still attenuate significantly. Because the frequencies which cell phones use are too high to reflect off the ionosphere as shortwave radio waves do, cell phone waves cannot travel via the ionospohere. The wavelength is the distance between repeating units of a wave pattern. ... Cellular redirects here. ... Relationship of the atmosphere and ionosphere The ionosphere is the part of the atmosphere that is ionized by solar radiation. ... This article is about an album. ...

See Diffraction and Attenuation for more. The intensity pattern formed on a screen by diffraction from a square aperture Diffraction refers to various phenomena associated with wave propagation, such as the bending, spreading and interference of waves passing by an object or aperture that disrupts the wave. ... Attenuation is the reduction in amplitude and intensity of a signal with respect to distance traveled through a medium. ...

Different operating frequencies

There are two frequency bands used by mobile telephones in the U.S. They are around 850 MHz and 1900 MHz. Many cellular repeaters only work with one of the two radio bands, although dual band models are available. Network operators normally only use one of the two frequency bands available, apart from Cingular, who uses the old 850 MHz AT&T network as well as their original 1900 MHz one. A band is a small section of the spectrum of radio communication frequencies, in which channels are usually used or set aside for the same purpose. ... In mobile phones, dual band refers to functionality that allows a cellphone to support two frequency bands out of the four major GSM bands. ... Cingular Wireless is the largest United States mobile phone company, with headquarters in Atlanta, Georgia, United States. ... AT&T Inc. ...

850 MHz

Used by Verizon Wireless, Pace Wireless, Cellular One and Alltel. Frequencies range 824 MHz to 894 MHz and are classified as Ultra High Frequency or UHF electromagnetic radiation. Cingular (since they purchased AT&T) uses this frequency as well as the 1900 MHz - this is why cell phones by this provider often find two networks. Verizon Wireless is the largest American wireless company and largest wireless data provider, based on revenues. ... Cellular One is the trade name of the cellular service offered by Western Wireless. ... Alltel (NYSE: AT) is an American telecommunications company with headquarters in Little Rock, Arkansas. ... Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz and 3. ... Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. ... Cingular Wireless is the largest United States mobile phone company, with headquarters in Atlanta, Georgia, United States. ... AT&T Inc. ... Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ...

1900 MHz

Used by T-Mobile, Sprint PCS, Cingular, Virgin Mobile, Dobson Communications and some Verizon markets. Frequencies range from 1850 MHz to 1990 MHz and are sometimes classified as belonging to the low energy microwave region of the electromagnetic spectrum, although they are also known as ultra-high frequency waves, due to the overlap of the ranges. T-Mobile logo T-Mobile is a multinational mobile phone operator. ... This article is about the telecommunications company; see sprints for the running term. ... Cingular Wireless is the largest United States mobile phone company, with headquarters in Atlanta, Georgia, United States. ... Virgin Mobile Ltd is a mobile phone service provider operating in the United Kingdom, Australia, Canada, South Africa, the United States and France. ... Dobson Cellular is a wireless telecommunications (i. ... This article or section should include material from Bell Atlantic This article or section should include material from GTE Verizon Communications (NYSE: VZ) is a local exchange telephone company formed by the merger of Bell Atlantic, a former Bell Operating Company, and GTE, which was the largest independant local exchange... Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) frequencies, but relatively short for radio waves. ... Legend Î³ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... This article is about the radio frequency. ...

FCC approval

Although there are some products on the market which are still pending FCC approval, they should have no problem gaining it. Although a license was originally required to broadcast at cell phone frequencies, it is legal to use the low power devices available today for home and small scale use in commercial areas (offices, shops, bars etc.). Many models already have FCC approval. The abbreviation FCC can refer to: Face-centered cubic (usually fcc), a crystallographic structure Federal Communications Commission, a US government organization Farm Credit Corporation/Farm Credit Canada, a Canadian government organization Families with Children from China, an adoption support organization Florida Christian College, a college in central Florida Fresno City... Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ... The abbreviation FCC can refer to: Face-centered cubic (usually fcc), a crystallographic structure Federal Communications Commission, a US government organization Farm Credit Corporation/Farm Credit Canada, a Canadian government organization Families with Children from China, an adoption support organization Florida Christian College, a college in central Florida Fresno City...

External links

This article may require more external links, but within the Wikipedia's content policies.
Please improve this article by adding appropriate external links. Please remove this tag when this is done. (talk)

Dead Cell Zones Web site listing poor coverage areas in USA including information on the causes of poor indoor coverage

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