When Is Guy Wire Needed On Mast Service

Tall structure designed to back up antennas

Radio masts and towers are typically tall structures designed to support antennas for telecommunication and dissemination, including television. There are 2 chief types: guyed and cocky-supporting structures. They are among the tallest human-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.

Radio Tower in Yekaterinburg, Lunacharskogo 212

Mast or tower? [edit]

A radio mast base showing how nigh all lateral support is provided past the guy-wires

The terms "mast" and "belfry" are often used interchangeably. However, in structural engineering terms, a tower is a cocky-supporting or cantilevered structure, while a mast is held upwards by stays or guys. Broadcast engineers in the Uk use the same terminology. A mast is a ground-based or rooftop construction that supports antennas at a elevation where they can satisfactorily send or receive radio waves. Typical masts are of steel lattice or tubular steel construction. Masts themselves play no part in the transmission of mobile telecommunication. Masts (to employ the ceremonious engineering terminology) tend to be cheaper to build but require an extended area surrounding them to suit the guy wires. Towers are more than commonly used in cities where land is in short supply.

The Tokyo Skytree, the tallest freestanding belfry in the globe, in 2012

There are a few borderline designs that are partly gratuitous-standing and partly guyed, chosen additionally guyed towers. For example:

The Gerbrandy tower consists of a self-supporting tower with a guyed mast on summit.
The few remaining Blaw-Knox towers do the opposite: they have a guyed lower department surmounted by a freestanding part.
Zendstation Smilde, a tall tower with a guyed mast on summit with guys which become to ground.
Torre de Collserola, a guyed tower with a guyed mast on tiptop where the belfry portion is non free-standing.

History [edit]

The beginning experiments in radio communication were conducted by Guglielmo Marconi beginning in 1894. In 1895–1896 he invented the vertical monopole or Marconi antenna, which was initially a wire suspended from a tall wooden pole. He found that the higher the antenna was suspended, the further he could transmit, the first recognition of the demand for acme in antennas. Radio began to exist used commercially for radiotelegraphic advice around 1900. During the beginning 20 years of radio, long distance radio stations used long wavelengths in the very low frequency band, and so fifty-fifty the tallest antennas were electrically short and had very low radiation resistance of v-25 Ohms, causing excessive power losses in the ground system. Radiotelegraphy stations used huge capacitively-toploaded flattop antennas consisting of horizontal wires strung between multiple 100–300 meters (330–980 ft) steel towers to increase efficiency.^[one]

AM radio broadcasting began effectually 1920. The allocation of the medium wave frequencies for dissemination raised the possibility of using single vertical masts without top loading. The antenna used for dissemination through the 1920s was the T-antenna, which consisted of 2 masts with a wire topload strung betwixt them, requiring twice the structure costs and country surface area of a single mast.^[1] In 1924 Stuart Ballantine published two historic papers which led to the evolution of the single mast antenna.^[1] In the first he derived the radiation resistance of a vertical conductor over a basis plane.^[2] He institute that the radiations resistance increased to a maximum at a length of 1⁄2 wavelength, then a mast around that length had an input resistance that was much higher than the ground resistance, reducing the fraction of transmitter power that was lost in the basis system without using a capacitive peak-load. In a 2d paper the same year he showed that the amount of power radiated horizontally in ground waves reached a maximum at a mast top of 5⁄viii wavelength.^[3]

By 1930 the expense of the T-antenna led broadcasters to adopt the mast radiator antenna, in which the metal structure of the mast itself functions as the antenna.^[four] One of the start types used was the diamond cantilever or Blaw-Knox tower. This had a diamond (rhombohedral) shape which made it rigid, so only one set of guy lines was needed, at its wide waist. The pointed lower end of the antenna concluded in a large ceramic insulator in the course of a brawl-and-socket articulation on a concrete base, relieving angle moments on the construction. The first, a 665 pes (203 m) half-moving ridge mast was installed at radio station WABC'southward 50 kW Wayne, New Jersey transmitter in 1931.^[five] ^[6] During the 1930s it was found that the diamond shape of the Blaw-Knox tower had an unfavorable current distribution which increased the ability emitted at high angles, causing multipath fading in the listening area.^[4] By the 1940s the AM broadcast industry had abandoned the Blaw-Knox design for the narrow, uniform cross section lattice mast used today, which had a better radiations pattern.

The rising of FM radio and goggle box dissemination in the 1940s and 50s created a need for fifty-fifty taller masts. The earlier AM broadcasting used LF and MF bands, where radio waves propagate as ground waves which follow the contour of the Globe. The ground-hugging waves allowed the signals to travel beyond the horizon, out to hundreds of kilometers. However the newer FM and TV transmitters used the VHF band, in which radio waves travel by line-of-sight, and then they are limited by the visual horizon. The only manner to cover larger areas is to raise the antenna loftier plenty so it has a line-of-sight path to them.

Until August eight, 1991, the Warsaw radio mast was the earth'due south tallest supported structure on land; its collapse left the KVLY/KTHI-TV mast equally the tallest. There are over l radio structures in the Usa that are 600 g (1968.5 ft) or taller.^[7]

Materials [edit]

Steel lattice [edit]

The Desa Coalfields Antenna Tower, behind the trees, is the tallest antenna tower in Malaysia, with the elevation of 95.3 m (313 ft), located at the front of the Sungai Buloh Prison

The steel lattice is the near widespread course of construction. It provides great strength, depression weight and current of air resistance, and economy in the utilise of materials. Lattices of triangular cross-section are most common, and square lattices are also widely used. Guyed masts are often used; the supporting guy lines conduct lateral forces such as wind loads, allowing the mast to be very narrow and simply constructed.

When built every bit a tower, the structure may be parallel-sided or taper over part or all of its pinnacle. When constructed of several sections which taper exponentially with height, in the manner of the Eiffel Tower, the belfry is said to exist an Eiffelized one. The Crystal Palace tower in London is an case.

Tubular steel [edit]

Guyed masts are sometimes also constructed out of steel tubes. This construction type has the advantage that cables and other components can be protected from atmospheric condition inside the tube and consequently the structure may look cleaner. These masts are mainly used for FM-/TV-broadcasting, merely sometimes also every bit mast radiator. The big mast of Mühlacker transmitting station is a adept example of this. A disadvantage of this mast type is that it is much more than affected by winds than masts with open up bodies. Several tubular guyed masts have complanate. In the Britain, the Emley Moor and Waltham Tv set stations masts collapsed in the 1960s. In Federal republic of germany the Bielstein transmitter collapsed in 1985. Tubular masts were non congenital in all countries. In Germany, France, Great britain, Czech republic, Slovakia, Japan and the Soviet Union, many tubular guyed masts were built, while in that location are nearly none in Poland or North America.

Several tubular guyed masts were congenital in cities in Russia and Ukraine. These masts featured horizontal crossbars running from the central mast construction to the guys and were built in the 1960s. The crossbars of these masts are equipped with a gangway that holds smaller antennas, though their main purpose is oscillation damping. The design designation of these masts is 30107 KM and they are exclusively used for FM and TV and are betwixt 150–200-metre (490–660 ft) tall with one exception. The exception being the mast in Vinnytsia which has top of 354 m (1161 ft) and is currently the tallest guyed tubular mast in the world afterwards the Belmont transmitting station was reduced in height in 2010.

Reinforced concrete [edit]

Reinforced concrete towers are relatively expensive to build but provide a loftier caste of mechanical rigidity in potent winds. This can be important when antennas with narrow beamwidths are used, such as those used for microwave point-to-point links, and when the structure is to exist occupied past people.

In the 1950s, AT&T congenital numerous concrete towers, more resembling silos than towers, for its showtime transcontinental microwave route.^[8] ^[9]

In Germany and the Netherlands virtually towers constructed for betoken-to-indicate microwave links are built of reinforced physical, while in the UK most are lattice towers.

Concrete towers can form prestigious landmarks, such as the CN Belfry in Toronto, Canada. In addition to accommodating technical staff, these buildings may have public areas such as ascertainment decks or restaurants.

The Stuttgart TV tower was the offset tower in the world to be built in reinforced physical. It was designed in 1956 past the local civil engineer Fritz Leonhardt.

Fiberglass [edit]

Fiberglass poles are occasionally used for low-power non-directional beacons or medium-wave broadcast transmitters.

Carbon Fiber [edit]

Carbon fibre monopoles and towers have traditionally been too expensive but contempo developments in the way the carbon fibre tow is spun have resulted in solutions that offer strengths exceeding steel (x times) for a fraction of the weight (70% less^[10]) which has allowed monopoles and towers to be congenital in locations that were too expensive or difficult to admission with the heavy lifting equipment that is needed for a steel structure.

Overall a carbon fiber structure is 40 - 50% faster to be erected compared to traditional building materials.

Wood [edit]

Wood has been superseded in use by metallic and composites for belfry structure. Many wood towers were congenital in the United kingdom during World War II because of a shortage of steel. In Federal republic of germany earlier World War II wooden towers were used at about all medium-wave transmission sites which accept all been demolished, except for the Gliwice Radio Tower.

Ferryside television relay station is an instance of a Tv set relay transmitter using a wooden pole.

Other types of antenna supports and structures [edit]

Poles [edit]

Shorter masts may consist of a self-supporting or guyed wooden pole, similar to a telegraph pole. Sometimes self-supporting tubular galvanized steel poles are used: these may be termed monopoles.

Buildings [edit]

In some cases, it is possible to install transmitting antennas on the roofs of tall buildings. In North America, for instance, at that place are transmitting antennas on the Empire State Edifice, the Willis Tower, Prudential Tower, 4 Times Square, and One Globe Trade Middle. The Northward Tower of the original World Trade Center also had a 110-metre (360 ft) telecommunications antenna atop its roof, constructed in 1978–1979, and began transmission in 1980. When the buildings collapsed, several local Goggle box and radio stations were knocked off the air until fill-in transmitters could exist put into service.^[11] Such facilities besides exist in Europe, peculiarly for portable radio services and low-power FM radio stations. In London, the BBC erected in 1936 a mast for broadcasting early television on ane of the towers of a Victorian edifice, the Alexandra Palace. It is still in use.

This 100-foot (30 m) alpine cross conceals equipment for T-Mobile at Epiphany Lutheran Church in Lake Worth, Florida, US. Completed in Dec 2009.

Disguised cell-sites [edit]

Disguised prison cell sites sometimes tin can be introduced into environments that require a depression-impact visual outcome, by being made to expect like trees, chimneys or other common structures.

Many people view bare cellphone towers as ugly and an intrusion into their neighbourhoods. Even though people increasingly depend upon cellular communications, they are opposed to the blank towers spoiling otherwise scenic views. Many companies offering to 'hide' cellphone towers in, or as, trees, church towers, flag poles, water tanks and other features.^[12] There are many providers that offer these services equally part of the normal tower installation and maintenance service. These are generally called "stealth towers" or "stealth installations", or simply curtained cell sites.

Communications tower, at the horizon on the right, camouflaged as a tall tree.

The level of detail and realism achieved past bearded cellphone towers is remarkably high; for example, such towers disguised as copse are nearly indistinguishable from the existent matter.^[13] Such towers can exist placed unobtrusively in national parks and other such protected places, such as towers disguised as cacti in United States' Coronado National Forest.^[14]

Fifty-fifty when disguised, however, such towers tin can create controversy; a tower doubling as a flagpole attracted controversy in 2004 in relation to the U.Southward. Presidential campaign of that year, and highlighted the sentiment that such disguises serve more to allow the installation of such towers in subterfuge away from public scrutiny rather than to serve towards the adornment of the landscape.^[15]

Mast radiators [edit]

A mast radiator or mast antenna is a radio tower or mast in which the whole structure is an antenna. Mast antennas are the transmitting antennas typical for long or medium wave broadcasting.

Structurally, the only difference is that some mast radiators require the mast base to be insulated from the ground. In the instance of an insulated tower, at that place will usually be one insulator supporting each leg. Some mast antenna designs do non require insulation, nonetheless, and then base insulation is not an essential characteristic.

Scope, pump-up and tiltover towers [edit]

A special course of the radio tower is the telescopic mast. These tin be erected very quickly. Scope masts are used predominantly in setting up temporary radio links for reporting on major news events, and for temporary communications in emergencies. They are also used in tactical military networks. They can save money by needing to withstand high winds simply when raised, and as such are widely used in amateur radio.

Telescopic masts consist of 2 or more concentric sections and come in two primary types:

Pump-up masts are frequently used on vehicles, and are raised to their full elevation pneumatically or hydraulically. They are usually only strong enough to back up adequately small antennas.
Scope lattice masts are raised by ways of a winch, which may exist powered past mitt or an electric motor. These tend to cater for greater heights and loads than the pump-upwards blazon. When retracted, the whole assembly can sometimes be lowered to a horizontal position by means of a second tiltover winch. This enables antennas to be fitted and adjusted at basis level before winching the mast up.

Balloons and kites [edit]

A tethered balloon or a kite can serve as a temporary support. It can bear an antenna or a wire (for VLF, LW or MW) upward to an advisable summit. Such an organisation is used occasionally past armed services agencies or radio amateurs. The American broadcasters TV Martí broadcast a television program to Cuba by means of such a balloon.

Drones [edit]

In 2013, involvement began in using unmanned aerial vehicles (drones) for telecom purposes.^[16]

Other special structures [edit]

For two VLF transmitters wire antennas spun across deep valleys are used. The wires are supported by small masts or towers or rock anchors. The aforementioned technique was also used at Criggion radio station.

For ELF transmitters ground dipole antennas are used. Such structures require no tall masts. They consist of two electrodes buried deep in the ground at least a few dozen kilometres apart. From the transmitter building to the electrodes, overhead feeder lines run. These lines look similar power lines of the 10 kV level, and are installed on like pylons.

Blueprint features [edit]

Economic and aesthetic considerations [edit]

The toll of a mast or tower is roughly proportional to the foursquare of its height.^{[ commendation needed ]}
A guyed mast is cheaper to build than a self-supporting tower of equal superlative.
A guyed mast needs additional land to adapt the guys, and is thus all-time suited to rural locations where land is relatively cheap. An unguyed tower will fit into a much smaller plot.
A steel lattice tower is cheaper to build than a concrete belfry of equal pinnacle.
Two small towers may be less intrusive, visually, than one big 1, especially if they await identical.
Towers wait less ugly if they and the antennas mounted on them appear symmetrical.
Concrete towers can exist built with aesthetic design, especially in Continental Europe. They are sometimes built in prominent places and include observation decks or restaurants.

Masts for HF/shortwave antennas [edit]

For transmissions in the shortwave range, there is little to be gained by raising the antenna more than a few wavelengths above basis level. Shortwave transmitters rarely use masts taller than nigh 100 metres.

Access for riggers [edit]

Because masts, towers and the antennas mounted on them crave maintenance, access to the whole of the construction is necessary. Pocket-size structures are typically accessed with a ladder. Larger structures, which tend to require more frequent maintenance, may have stairs and sometimes a lift, likewise called a service lift.

Aircraft alert features [edit]

Tall structures in excess of certain legislated heights are often equipped with aircraft alert lamps, usually red, to warn pilots of the structure'south existence. In the past, ruggedized and under-run filament lamps were used to maximize the bulb life. Alternatively, neon lamps were used. Nowadays such lamps tend to use LED arrays.

Summit requirements vary beyond states and countries, and may include boosted rules such as requiring a white flashing strobe in the daytime and pulsating cherry-red fixtures at night. Structures over a certain height may also exist required to exist painted with contrasting color schemes such as white and orange or white and red to make them more visible against the sky.

Light pollution and nuisance lighting [edit]

In some countries where light pollution is a business organization, tower heights may be restricted then as to reduce or eliminate the need for shipping alarm lights. For example, in the United States the 1996 Telecommunication Act allows local jurisdictions to set maximum heights for towers, such as limiting belfry height to below 200 feet (61 m) and therefore not requiring aircraft illumination under US Federal Communications Commission (FCC) rules.

Current of air-induced oscillations [edit]

One problem with radio masts is the danger of wind-induced oscillations. This is especially a business organisation with steel tube construction. One tin can reduce this past building cylindrical daze-mounts into the construction. 1 finds such daze-mounts, which look similar cylinders thicker than the mast, for example, at the radio masts of DHO38 in Saterland. At that place are besides constructions, which consist of a free-continuing tower, usually from reinforced concrete, onto which a guyed radio mast is installed. Ane case is the Gerbrandy Tower in Lopik, Netherlands. Further towers of this building method tin be found near Smilde, Netherlands and the Fernsehturm in Waldenburg, Germany.

Run a risk to birds [edit]

Radio, television receiver and cell towers accept been documented to pose a hazard to birds. Reports have been issued documenting known bird fatalities and calling for enquiry to find ways to minimize the hazard that communications towers can pose to birds.^[17] ^[eighteen]

In that location have also been instances of rare birds nesting in prison cell towers and thereby preventing repair piece of work due to legislation intended to protect them.^[19] ^[xx]

Catastrophic collapses [edit]

See as well [edit]

Antenna (radio)
Lattice belfry (likewise lists radio towers built of wood)
Mast radiator
Targeting Towers
Telecom infrastructure sharing
Tower assortment
Transmitter station
Prison cell site
Measurement tower
Mobile cell sites
Cell on wheels
Personal RF safety monitor

References [edit]

^ ^a ^b ^c Laport, Edmund A. (1952). Radio Antenna Engineering. McGraw-Hill Book Co. pp. 77–78.
^ Ballantine, Stuart (December 1924). "On the Optimum Transmitting Wave Length for a Vertical Antenna over Perfect Earth". Proceedings of the Institute of Radio Engineers. Institute of Electrical and Electronics Engineers. 12 (half-dozen): 833–839. doi:x.1109/JRPROC.1924.220011. S2CID 51639724.
^ Ballantine, Stuart (December 1924). "On the Radiations Resistance of a Simple Vertical Antenna at Wave Lengths beneath the Primal". Proceedings of the Establish of Radio Engineers. Found of Electric and Electronics Engineers. 12 (6): 823–832. doi:10.1109/JRPROC.1924.220010. S2CID 51654399.
^ ^a ^b Laport, Edmund A. (1952). Radio Antenna Engineering science. McGraw-Hill Book Co. pp. 79–81.
^ "Half wave mast antenna: A 665 pes construction which constitutes a new departure" (PDF). Radio-Craft. Mount Morris, Illinois: Techni-Craft Publishing Corp. 3 (5): 269. November 1931. Retrieved August 31, 2014.
^ Siemens, Frederick (December 1931). "WABC'south New "Wire-less" Antenna" (PDF). Radio News. New York: Teck Publishing Corp. viii (6): 462–463. Retrieved May 26, 2015.
^ "Diagrams". SkyscraperPage. Skyscraper Source Media. {{cite spider web}}: CS1 maint: url-status (link)
^ Weishan, Wayne (May 26, 2008). LaFrance, Albert (ed.). "AT&T'southward Concrete Microwave Towers". The Microwave Radio and Coaxial Cable Networks of the Bell System . Retrieved 2021-03-26 . {{cite web}}: CS1 maint: url-status (link)
^ Michaels, Terry (July 31, 2010). LaFrance, Albert (ed.). "The Stations of AT&T's First Transcontinental Microwave Radio Route". The Microwave Radio and Coaxial Cable Networks of the Bell System. Archived from the original on 2021-02-11. Retrieved 2021-03-26 .
^ "edotco Pioneers the First Carbon Fibre Tower in Asia". edotco. 2016-08-08. Retrieved 2021-08-11 .
^ "Some New York City TV and radio stations off the air afterward Globe Trade Centre collapse". Archived from the original on 2006-12-31.
^ "CARC - UNC-Charlotte - Course grand Clean Room Facilities". ece.uncc.edu. Archived from the original on 12 September 2006.
^ Armstrong, Due west.P. (2004). "Cell Phone Trees". Wayne's Word. Archived from the original on 2019-08-eleven.
^ Wunderlich, Marv; Wunderlich, Elaine. "Sabino Canyon Recreational Area inside the Coronado National Woods". Marlaine Services. {{cite web}}: CS1 maint: url-status (link)
^ Conway, Bruce. "Stealth Cell towers and the 2004 U.S. Presidential Elections". Lightwatcher. Archived from the original on 2007-02-17.
^ Jones, Trahern (2013-04-27). "Telecom-equipped drones could revolutionize wireless market". The Arizona Republic. {{cite web}}: CS1 maint: url-status (link)
^ Shire, Gavin G.; Karen Brown; Gerald Winegrad (June 2000). "Communication Towers: A Deadly Take chances to Birds" (PDF). American Bird Conservancy. Earthjustice. Retrieved 2010-09-29 .
^ "Avian Collisions at Communication Towers - Sources of Data". U.S. Fish and Wildlife Service. June 1, 2009. Retrieved 2010-08-xiii .
^ "Nesting falcon hits Vodafone customers in Southampton". BBC News. 15 Apr 2013. Retrieved twenty May 2013.
^ Ray, Pecker (17 April 2013). "Aroused Birds fire back: Vulture cousins menace Britain city's mobiles". The Register. Retrieved 20 May 2013.

Farther reading [edit]

Sreevidya, South., and Subramanian, N., Artful Appraisal to Antenna Towers, Periodical of Architectural Engineering, American Guild of Civil Engineers, Vol. 9, No. three, September 2003, pp. 102–108

External links [edit]

All US Towers over 200 feet, transmitting on sure frequencies, or have certain transmitters over a sure power, must be registered in the US. This is the online directory.
The Manual Gallery: Broadcast Transmission Sites in the UK
The Manual Gallery: Amalgam Stayed Masts
Scott Fybush, international belfry photographer who has documented thousands of towers in his travels
Tom Bosscher of Western Michigan'southward website on towers of Michigan
Mike Fitzpatrick's NECRAT.U.s.a. tower based website contains tower pictures from New England, New York, and beyond.
Turkish towers (in Turkish)
Amateur Radio Belfry construction project
Displays over 12,000 80+ meter tall towers used in air current resource assessment
French towers (in French)
The Legal Mural When a Tower Collapses
Richard Moore'south Anorak Zone Photograph Gallery of United kingdom TV and Radio transmission sites
Mobile Phone Masts & Radio Base of operations Station Planning U.k.
Various Advice Masts &Towers in Atlanta, Georgia, Us
Britain masts and towers at thebigtower.com
Searchable map of all registered transmitters in Commonwealth of australia