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<br /> Association of Telecommunications Officers and and lattice,or self-support towers,which have three or four
<br /> Administrators, the U.S.Conference of Mayors, the National sides of open-framed steel supports. Some cellular antennas can
<br /> League of Cities,and the National Association of Counties have occupy space on other types of communication towers when the
<br /> filed similar objections. engineering is feasible.This is known as using a donor site to
<br /> troubleshoot a small gap or dead spot within the grid.A micro-
<br /> Nature of the Technology cell or repeater facility is installed on a preexisting tower to
<br /> Low-power mobile radio communication,also known as cellular ensure that transmissions within that area are clear.Antennas
<br /> communication, is accomplished by linking a wireless network can also be placed on rooftops and other building features if the
<br /> of radio wave transmitting devices(portable phones,pagers,or building's height can accommodate their service area. In
<br /> car phones) to the conventional ground-wired communications addition,antennas have been mounted on silos,water tanks,
<br /> system (telephone lines) through a series of short-range, windmills,and smokestacks.As cellular use proliferates and the
<br /> contiguous cells that are part of an evolving cell grid. technology improves, the trend toward shorter towers and Iess
<br /> For example,a portable phone transmits a signal to the obtrusive mounting fixtures is likely to prevail.
<br /> nearest cellular antenna.The call is relayed from the antenna to Antennas are of three types:omnidirectional,directional,and
<br /> the nearest land-based telephone line or microwave dish,and microwave. Omnidirectional antennas,also called whip
<br /> then to a central switching computer. From there„the call is antennas,serve a 360-degree area. Directional antennas,also
<br /> sent to its destination,either a land-based telephone via the known as panel antennas or rectangular antennas,are used to
<br /> land-based line or another mobile communication device via the achieve transmission or reception in a specific direction.
<br /> closest cellular antenna. Microwave antennas are used to link different types of
<br /> Calls can originate or be received from a wireless source telecommunications facilities,such as when a portable phone
<br /> because antennas share a fixed number of frequencies across the user calls a conventional telephone number.
<br /> cellular grid.In other words,while a caller may dial her destina-
<br /> tion number from within the radius of one cell antenna,she may Screening, Landscaping, and Setbacks
<br /> travel into the radius of another during the call.The call proceeds The most common objection to cellular towers and antennas is
<br /> uninterrupted as the transmission is"patched”from one antenna their aesthetic impact. Residents, many of whom use the
<br /> to the next.While the caller is moving,the cellular antennas are technology,do not want to see the towers cluttering their
<br /> automatically locating an unoccupied frequency on the next landscape or degrading property values.Planners and industry
<br /> antenna,thus enabling continued transmission. professionals have gone to great lengths to screen,conceal,and
<br /> When a caller cannot successfully place or maintain a call, set back towers and their associated buildings.All the
<br /> either he is out of range or the nearest antenna is at full ordinances reviewed contain some son of requirement for
<br /> capacity.Cellular tower technology differs from satellite, maintaining existing vegetation or installing landscaping for the
<br /> microwave,or land-based communications in that it is based on purpose of screening the base of the tower and the storage
<br /> a network of short-range cell sites with a fixed capacity.If the building.Towers can also be camouflaged to blend with the
<br /> cells are not linked by cellular towers, microwave dishes,or surrounding environment through the use of color,materials,
<br /> ground-wired towers,transmission will fail. Similarly,if a cell is and design. For instance,Jefferson Parish,Louisiana, requires
<br /> crowded by too many users,it must be"split" into two cells, that all cellular towers be disguised as trees:
<br /> each having its own radius;thus,only the cellular antennas of 1.The entire facility must be aesthetically and architecturally
<br /> separate carriers can share space on the same tower. It is compatible with its environment.The use of residentially
<br /> physically impossible for a single carrier to deliver service compatible materials such as wood,brick,or stucco is
<br /> successfully if its antennas are not dispersed. required for associated support buildings,which shall be
<br /> Most local regulations require that all technically available designed to architecturally match the exterior of residential
<br /> space on existing towers within the jurisdiction be used before structures within the neighborhood.In no case will metal
<br /> new towers are erected.In other words,cellular carriers must exteriors be allowed for accessory buildings.
<br /> lease space to other carriers on their towers;the cellular industry 2.The tower itself must be of such design and treated with an
<br /> considers this leasing arrangement to be a less-than-ideal architectural material so that it is camouflaged to resemble a
<br /> solution.As the demand for cellular telecommunications woody tree with a single trunk and branches on its upper part.
<br /> increases,cells in a given area must be subdivided,or additional
<br /> carriers must be permitted to operate there.The end result is the Setback distances can be guided by aesthetic and safety
<br /> need for more towers. concerns. Most are expressed as a percentage of the tower
<br /> height. In the Pensacola, Florida,ordinance, the setback serves a
<br /> Towers and Antennas primarily aesthetic purpose:
<br /> Towers may need to range in height from 50 to 200 feet so that (71he distance between the base of the communications towers
<br /> antennas can overcome the challenges posed to communications and any residential zoning district or any historical or
<br /> by local topography.The required height is usually proportional to architecturally significant building must equal 20 percent of the
<br /> a combination of the distance antennas can cover and the demand tower height.
<br /> within their radius.Higher towers generally cover a larger
<br /> geographic area,but have a lower service demand,and are known Safety-oriented setbacks establish a clear zone for falling
<br /> as coverage sites. Shorter towers,known as capacity sites,cover tower debris or the worst-case scenario, the tower's collapse.
<br /> smaller areas with a more concentrated demand.Tower height can Falling zones for cowers vary with their design.At most,they
<br /> also vary according to engineering requirements for a specific site will collapse to a distance equal to their full height, but many
<br /> or the technical capabilities of the antennas being mounted. are designed to collapse first toward their base.The Oldham
<br /> In addition to dedicated, free-standing cellular towers County, Kentucky,setback provisions are designed with falling
<br /> (monopoles), there are guyed towers (anchored with guy wires) zones in mind:
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