Radio masts and towers

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Tokyo Tower Tokyo Tower M4854.jpg
Tokyo Tower

Radio masts and towers are, typically, tall structures designed to support antennas for telecommunications and broadcasting, including television. There are two main types: guyed and self-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.

Contents

In the case of a mast radiator or radiating tower, the whole mast or tower is itself the transmitting antenna.

Mast or tower?

A radio mast base showing how virtually all lateral support is provided by the guy-wires Tower base.jpg
A radio mast base showing how virtually all lateral support is provided by the guy-wires

The terms "mast" and "tower" are often used interchangeably. However, in structural engineering terms, a tower is a self-supporting or cantilevered structure, while a mast is held up by stays or guys. Broadcast engineers in the UK use the same terminology. A mast is a ground-based or rooftop structure that supports antennas at a height 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 telecommunications. Masts (to use the civil engineering terminology) tend to be cheaper to build but require an extended area surrounding them to accommodate the guy wires. Towers are more commonly used in cities where land is in short supply.

The Tokyo Skytree, the tallest freestanding tower in the world, in 2012 Tokyo Sky Tree 2012 IV.JPG
The Tokyo Skytree, the tallest freestanding tower in the world, in 2012

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

History

The first 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 need for height in antennas. Radio began to be used commercially for radiotelegraphic communication around 1900. During the first 20 years of radio, long distance radio stations used long wavelengths in the very low frequency band, so even the tallest antennas were electrically short and had very low radiation resistance of 5-25 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. [1]

Multiwire broadcast T-antenna of early AM station WBZ, Springfield, Massachusetts, 1925. Wire T antenna station WBZ 1925.jpg
Multiwire broadcast T-antenna of early AM station WBZ, Springfield, Massachusetts, 1925.

AM radio broadcasting began around 1920. The allocation of the medium wave frequencies for broadcasting raised the possibility of using single vertical masts without top loading. The antenna used for broadcasting through the 1920s was the T-antenna, which consisted of two masts with a wire topload strung between them, requiring twice the construction costs and land area of a single mast. [1] In 1924 Stuart Ballantine published two historic papers which led to the development of the single mast antenna. [1] In the first he derived the radiation resistance of a vertical conductor over a ground plane. [2] He found that the radiation resistance increased to a maximum at a length of 12  wavelength, so 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 ground system without using a capacitive top-load. In a second paper the same year he showed that the amount of power radiated horizontally in ground waves reached a maximum at a mast height of 58  wavelength. [3]

Masts of the Rugby VLF transmitter near Rugby, England Hillmorton radio masts.jpg
Masts of the Rugby VLF transmitter near Rugby, England

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. [4] One of the first 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 ended in a large ceramic insulator in the form of a ball-and-socket joint on a concrete base, relieving bending moments on the structure. The first, a 665 foot (203 m) half-wave mast was installed at radio station WABC's 50 kW Wayne, New Jersey transmitter in 1931. [5] [6] During the 1930s it was found that the diamond shape of the Blaw-Knox tower had an unfavorable current distribution which increased the power 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 radiation pattern.

The rise of FM radio and television broadcasting in the 1940s and 50s created a need for even taller masts. The earlier AM broadcasting used LF and MF bands, where radio waves propagate as ground waves which follow the contour of the Earth. 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, so they are limited by the visual horizon. The only way to cover larger areas is to raise the antenna high enough so it has a line-of-sight path to them.

Until August 8, 1991, the Warsaw radio mast was the world's tallest supported structure on land; its collapse left the KVLY/KTHI-TV mast as the tallest. There are over 50 radio structures in the United States that are 600 m (1968.5 ft) or taller. [7]

Materials

Steel lattice

Russian TV tower, Penza Russian TV tower (Penza).JPG
Russian TV tower, Penza

The steel lattice is the most widespread form of construction. It provides great strength, low weight and wind resistance, and economy in the use 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 carry lateral forces such as wind loads, allowing the mast to be very narrow and simply constructed.

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

Tubular steel

Typical 200 foot (61 m) triangular guyed lattice mast of an AM radio station in Mount Vernon, Washington, US KBRC antenna tower guy wires.JPG
Typical 200 foot (61 m) triangular guyed lattice mast of an AM radio station in Mount Vernon, Washington, US

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 weather inside the tube and consequently the structure may look cleaner. These masts are mainly used for FM-/TV-broadcasting, but sometimes also as mast radiator. The big mast of Mühlacker transmitting station is a good example of this. A disadvantage of this mast type is that it is much more affected by winds than masts with open bodies. Several tubular guyed masts have collapsed. In the UK, the Emley Moor and Waltham TV stations masts collapsed in the 1960s. In Germany the Bielstein transmitter collapsed in 1985. Tubular masts were not built in all countries. In Germany, France, UK, Czech Republic, Slovakia, Japan and the Soviet Union, many tubular guyed masts were built, while there are nearly none in Poland or North America.

In several cities in Russia and Ukraine several tubular guyed masts with crossbars running from the mast structure to the guys were built in the 1960s. All these masts, which are designed as 30107 KM, are exclusively used for FM and TV transmission and, except for the mast in Vinnytsia, are between 150–200-metre (490–660 ft) tall. The crossbars of these masts are equipped with a gangway that holds smaller antennas, though their main purpose is oscillation damping.

Reinforced concrete

TV Tower in Stuttgart, Germany: the first reinforced-concrete TV tower. Fernsehturm stuttgart.jpg
TV Tower in Stuttgart, Germany: the first reinforced-concrete TV tower.

Reinforced concrete towers are relatively expensive to build but provide a high degree of mechanical rigidity in strong 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 be occupied by people.

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

In Germany and the Netherlands most towers constructed for point-to-point microwave links are built of reinforced concrete, while in the UK most are lattice towers.

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

The Stuttgart TV tower was the first tower in the world to be built in reinforced concrete. It was designed in 1956 by the local civil engineer Fritz Leonhardt.

Milad Tower, Tehran, Iran Bordzhe Milad.jpg
Milad Tower, Tehran, Iran

Fiberglass and other composite materials

Fiberglass poles are occasionally used for low-power non-directional beacons or medium-wave broadcast transmitters. Carbon fibre monopoles and towers have traditionally been too expensive but recent developments in the way the carbon fibre tow is spun have resulted in solutions that offer strengths similar or exceeding steel for a fraction of the weight which has allowed monopoles and towers to be built in locations that were too expensive or difficult to access with the heavy lifting equipment that is needed for a steel structure.

Kamzik TV Tower, overlooking Bratislava, Slovakia. Bratislava, Stare Mesto, Slavin, pohled na vysilac Kamzik.jpg
Kamzík TV Tower, overlooking Bratislava, Slovakia.

Wood

Wood has been superseded in use by metal and composites for tower construction. Many wood towers were built in the UK during World War II because of a shortage of steel. In Germany before World War II wooden towers were used at nearly all medium-wave transmission sites which have all been demolished, except for the Gliwice Radio Tower.

Ferryside television relay station is an example of a TV relay transmitter using a wooden pole.

Other types of antenna supports and structures

Poles

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

In some cases, it is possible to install transmitting antennas on the roofs of tall buildings. In North America, for instance, there are transmitting antennas on the Empire State Building, the Willis Tower, 4 Times Square, and One World Trade Center. The North 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 TV and radio stations were knocked off the air until backup transmitters could be put into service. [10] Such facilities also exist in Europe, particularly for portable radio services and low-power FM radio stations. In London, the BBC erected in 1936 a mast for broadcasting early television on one of the towers of a Victorian building, the Alexandra Palace. It is still in use.

This 100-foot (30 m) tall cross conceals equipment for T-Mobile at Epiphany Lutheran Church in Lake Worth, Florida, US. Completed in December 2009. Finishing cross view.JPG
This 100-foot (30 m) tall cross conceals equipment for T-Mobile at Epiphany Lutheran Church in Lake Worth, Florida, US. Completed in December 2009.

Disguised cell-sites

Disguised cell sites sometimes can be introduced into environments that require a low-impact visual outcome, by being made to look 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 bare towers spoiling otherwise scenic views. Many companies offer to 'hide' cellphone towers in, or as, trees, church towers, flag poles, water tanks and other features. [11] There are many providers that offer these services as part of the normal tower installation and maintenance service. These are generally called "stealth towers" or "stealth installations", or simply concealed cell sites.

Communications tower, at the horizon on the right, camouflaged as a tall tree. Wuzhen Xizha 2009-17.jpg
Communications tower, at the horizon on the right, camouflaged as a tall tree.

The level of detail and realism achieved by disguised cellphone towers is remarkably high; for example, such towers disguised as trees are nearly indistinguishable from the real thing, even for local wildlife (who additionally benefit from the artificial flora). [12] Such towers can be placed unobtrusively in national parks and other such protected places, such as towers disguised as cacti in United States' Coronado National Forest. [13]

Even when disguised, however, such towers can create controversy; a tower doubling as a flagpole attracted controversy in 2004 in relation to the U.S. 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 beautification of the landscape. [14]

Mast radiators

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 case of an insulated tower, there will usually be one insulator supporting each leg. Some mast antenna designs do not require insulation, however, so base insulation is not an essential feature.

Telescopic, pump-up and tiltover towers

A special form of the radio tower is the telescopic mast. These can be erected very quickly. Telescopic 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 only when raised, and as such are widely used in amateur radio.

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

Balloons and kites

A tethered balloon or a kite can serve as a temporary support. It can carry an antenna or a wire (for VLF, LW or MW) up to an appropriate height. Such an arrangement is used occasionally by military agencies or radio amateurs. The American broadcasters TV Martí broadcast a television program to Cuba by means of such a balloon.

Drones

In 2013, interest began in using unmanned aerial vehicles (drones) for telecom purposes. [15]

Other special structures

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 same 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 like power lines of the 10 kV level, and are installed on similar pylons.

Design features

Economic and aesthetic considerations

Felsenegg-Girstel TV-tower Felsenegg - Girstel IMG 3263.jpg
Felsenegg-Girstel TV-tower
Uetliberg TV-tower Limmattal - Swisscom-Tower - Uetlibergturm IMG 1652.JPG
Uetliberg TV-tower
A radio amateur's do it yourself steel-lattice tower AmateurRadioAntenna.JPG
A radio amateur's do it yourself steel-lattice tower

Masts for HF/shortwave antennas

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

Access for riggers

Because masts, towers and the antennas mounted on them require maintenance, access to the whole of the structure is necessary. Small structures are typically accessed with a ladder. Larger structures, which tend to require more frequent maintenance, may have stairs and sometimes a lift, also called a service elevator.

Aircraft warning features

Tall structures in excess of certain legislated heights are often equipped with aircraft warning lamps, usually red, to warn pilots of the structure's 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.

Height requirements vary across states and countries, and may include additional rules such as requiring a white flashing strobe in the daytime and pulsating red fixtures at night. Structures over a certain height may also be required to be 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

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

Wind-induced oscillations

One problem with radio masts is the danger of wind-induced oscillations. This is particularly a concern with steel tube construction. One can reduce this by building cylindrical shock-mounts into the construction. One finds such shock-mounts, which look like cylinders thicker than the mast, for example, at the radio masts of DHO38 in Saterland. There are also constructions, which consist of a free-standing tower, usually from reinforced concrete, onto which a guyed radio mast is installed. One example is the Gerbrandy Tower in Lopik, Netherlands. Further towers of this building method can be found near Smilde, Netherlands and the Fernsehturm in Waldenburg, Germany.

Hazard to birds

Radio, television and cell towers have been documented to pose a hazard to birds. Reports have been issued documenting known bird fatalities and calling for research to find ways to minimize the hazard that communications towers can pose to birds. [16] [17]

There have also been instances of rare birds nesting in cell towers and thereby preventing repair work due to legislation intended to protect them. [18] [19]

Catastrophic collapses

See also

Related Research Articles

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Medium wave (MW) is the part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. The spectrum provides about 120 channels with limited sound quality. During daytime, only local stations can be received. Propagation in the night allows strong signals within a range of about 2000 km. This can cause massive interference because on most channels, about 20 to 50 transmitters operate simultaneously worldwide. In addition to that, amplitude modulation (AM) is prone to interference by all sorts of electronic devices, especially power supplies and computers. Strong transmitters cover larger areas than on the FM broadcast band but require more energy. Digital modes are possible but have not reached the momentum yet.

Radio clock type of clock which self-synchronizes its time using dedicated radio transmitters

A radio clock or radio-controlled clock (RCC) is a clock or watch that is automatically synchronized to a time code transmitted by a radio transmitter connected to a time standard such as an atomic clock. Such a clock may be synchronized to the time sent by a single transmitter, such as many national or regional time transmitters, or may use the multiple transmitters used by satellite navigation systems such as GPS. Such systems may be used to automatically set clocks or for any purpose where accurate time is needed. RC clocks may include any feature available for a clock, such as alarm function, display of ambient temperature and humidity, broadcast radio reception, etc.

Warsaw radio mast former radio mast in Poland

The Warsaw Radio Mast was a telecommunications tower located near the town of Gąbin, central Poland, and the world's tallest structure at 646.38 metres (2,120.7 ft) from 1974 until its collapse on 8 August 1991. It was the second tallest structure ever built, being surpassed as the tallest by the Burj Khalifa tower in the United Arab Emirates, completed in 2009.

Sender Zehlendorf

Sender Zehlendorf is a radio transmission facility which has been in service since 1936, when a short wave transmitter was built in Zehlendorf as part of the establishment of permanent radio services. This Zehlendorf site, which until the end of World War II was referred to as the Rehmate Radio Transmission Centre, had 26 different antennas.

Roumoules radio transmitter

The Roumoules transmitter is the main broadcasting facility for longwave and mediumwave broadcasting of Radio Monte Carlo near Roumoules, France and is owned by Monaco Media Diffusion. The 1000 and 2000kW transmitters installed are among the most powerful in the world and can be received well at nighttime throughout Europe.

Mühlacker radio transmitter

The Mühlacker Broadcasting Transmission Facility is a radio transmission facility near Mühlacker, Germany, first put into service on November 21, 1930. It uses two guyed steel tube masts as aerials and one guyed steel framework mast, which are insulated against ground. It has two transmission aerials for shortwave and one free standing steel framework tower for directional radio services. The shortwave transmitter was shut off on October 19, 2004. The medium wave transmitter was switched off in January 2012.

Ismaning radio transmitter Architectural structure

The Transmitter Ismaning was a large radio transmitting station near Ismaning, Bavaria, Germany. It was inaugurated in 1932. From 1932 to 1934 this transmitter used a T-antenna as transmitting antenna, which was spun between two 115-metre-high free-standing wooden lattice towers, which were 240 metres apart. As this antenna had an unfavourable vertical radiation pattern, which produced much skywave resulting in a too small fading-free reception area at night, in 1934 a new antenna was installed. Therefore, one of the towers was dismantled and rebuilt on a 39-metre-high (128 ft) wooden lattice base. While this work took place, an L-Antenna was used, which was spun between the other tower and a small auxiliary wooden tower. It became defunct in 1977 and was destroyed in 1983.

The Monte Ceneri transmitter was first established as the nationwide medium-wave radio transmission station for Italian-speaking Switzerland in 1933. Located on Monte Ceneri in Ticino, it broadcast on a frequency of 558 kHz.

Blaw-Knox tower

The Blaw-Knox company was a manufacturer of steel structures and construction equipment based in Pittsburgh, Pennsylvania. The company is today best known for its radio towers, most of which were constructed during the 1930s in the United States. Although Blaw-Knox built many kinds of towers, the term Blaw-Knox tower usually refers to the company's unusual "diamond cantilever" design, which is stabilized by guy wires attached only at the vertical center of the mast, where its cross-section is widest. During the 1930s AM radio broadcasting stations adopted single mast radiator antennas, and the Blaw-Knox design was the first type used. A 1942 advertisement claims that 70% of all radio towers in the US at the time were built by Blaw-Knox.

Peterborough transmitting station

The Peterborough transmitting station is a broadcasting and telecommunications facility at Morborne Hill, near Peterborough,.

Mast radiator Radio antenna consisting of a vertical mast in which the mast structure is energized and functions as the antenna

A mast radiator is a radio mast or tower in which the metal structure itself is energized and functions as an antenna. This design, first used widely in the 1930s, is commonly used for transmitting antennas operating at low frequencies, in the LF and MF bands, in particular those used for AM radio broadcasting stations. The conductive steel mast is electrically connected to the transmitter. Its base is usually mounted on a nonconductive support to insulate it from the ground. A mast radiator is a form of monopole antenna.

Partially guyed tower Tower structure

A partially guyed tower is a tower structure which consists of a free-standing basement, in most cases of concrete or of lattice steel with a guyed mast on the top. The anchor basements of the guyed mast can be on the top of the tower or on the ground.

An umbrella antenna is a top-loaded wire monopole antenna, consisting in most cases of a mast fed at the ground end, to which a number of radial wires are connected at the top, sloping downwards. They are used as transmitting antennas below 1 MHz, in the LF and particularly the VLF bands, at frequencies sufficiently low that it is impractical or infeasible to build a full size quarter-wave monopole antenna. The outer end of each radial wire, sloping down from the top of the antenna, is connected by an insulator to a supporting rope or (usually) insulated cable anchored to the ground; the radial wires can also support the mast as guy wires. The radial wires make the antenna look like the frame of a giant umbrella – without the cloth – hence the name.

Wiederau transmitter architectural structure

The Wiederau transmitter is the oldest broadcasting facility in Saxony. It is located near Wiederau, a village which is part of the municipality of Pegau, and is used for medium-wave, FM and Television broadcasting.

Golm transmitter was a medium wave broadcasting facility on the area of a former Reichsarbeitsdienst officer candidate school at Kuhforter Damm in Golm near Potsdam. It entered service in 1948 as the central broadcast transmitter for Brandenburg state. Until 1979 it used a wooden lattice tower of 98 m (322 ft) height with a horizontal wooden cross on its top as its antenna support. The ends of the beams of this cross were connected with wires. From the centre of each of these horizontal wires, a vertical wire was run down to the antenna tuner which was located in a building under the feet of the tower construction. The antenna of Golm transmitter consisted therefore of 4 T-antennas connected in parallel, forming an omnidirectional antenna with a natural wavelength of 528 m. The transmitter was built from second-hand parts obtained by dismantling a site in Reichenbach, Upper Lusatia. Test transmissions were undertaken on 16 April 1948, and from 1 May 1948 the facility operated on 564 kHz.

Ravensburg-Horgenzell transmitter architectural structure

Ravensburg-Horgenzell transmitter was a mediumwave broadcasting facility of Deutsche Telekom used for transmitting the program of Deutschlandfunk on the area of community Horgenzell northwest of Ravensburg in Baden-Württemberg. It was inaugurated on August 23, 1951 and used until 1959 for transmitting the radio programme of SWF with a transmission power of 40 kW on 1538 kHz. As antenna, it used a 120 metre tall guyed ground-fed lattice steel mast radiator at 47°47'10" N and 9°31'16" E.

Hoher Meissner transmitter is a facility for FM and TV broadcasting on Hoher Meissner mountain in Northern Hesse. The transmitter was inaugurated in 1952.

Lisnagarvey transmitting station facility for mediumwave broadcasting located in the townland of Magherageery

The Lisnagarvey transmitting station is a facility for mediumwave broadcasting located in the townland of Magherageery, on the southern edge of Lisburn, Northern Ireland. It is close to Sprucefield shopping centre and about one mile from the middle of Lisburn.

Col de la Madone transmitter is a very large broadcasting centre operated by Radio Monte Carlo north of Fontbonne, near Nice and Monaco, in France. It was established in 1965 and was used until completion of Roumoules radio transmitter for longwave broadcasting, using 3 320 metres tall guyed mast radiators, which do not exist any more. It was used for broadcasting on 702 kHz and 1467 kHz. Both antennas consist of 2 guyed mast radiators insulated against ground. The masts of the antenna for 1467 kHz are 101 metres tall and oriented in North-South direction. The masts of the antenna for 702 kHz are oriented in East-West direction pointing towards Milan, as it is used for transmitting a radio program in Italian language toward Italy. The western mast of this antenna, which acts as reflector, has a height of 250 metres while the eastern mast which is the radiator is 215 metres taller. A bit souther, there is close to a military radar site a centre for FM-broadcasting and on Mount Angel there is a 146 metres tall partially guyed tower, which consists of a grounded lattice tower as basement and a guyed mast radiator insulated against ground as top. It was built in 1946 and first used for mediumwave broadcasting, but is today used for TV-broadcasting. Nearby there is also the shortwave transmitter of RMC with several dipole walls.

Emley Moor transmitting station telecommunications and broadcasting facility in Yorkshire, England

The Emley Moor transmitting station is a telecommunications and broadcasting facility on Emley Moor, 1 mile (1.6 km) west of the village centre of Emley, mid-way between the villages of Kirkburton and West Bretton, in turn between Huddersfield and Wakefield, West Yorkshire, England. It is made up of a 1,084-foot-tall (330.4 m) concrete tower and apparatus which began transmitting in 1971. It is protected under UK law as a Grade II listed building. It is the tallest freestanding structure in the United Kingdom, seventh-tallest freestanding structure and fourth-tallest tower in Europe outside Russia, and 24th-tallest tower in the world.

References

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  2. 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 Electronic Engineers. 12 (6): 833–839. doi:10.1109/JRPROC.1924.220011 . Retrieved 15 April 2020.
  3. Ballantine, Stuart (December 1924). "On the Radiation Resistance of a Simple Vertical Antenna at Wave Lengths below the Fundamental". Proceedings of the Institute of Radio Engineers. Institute of Electrical and Electronic Engineers. 12 (6): 823–832. doi:10.1109/JRPROC.1924.220010 . Retrieved 18 April 2020.
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  10. "Some New York City TV and radio stations off the air after World Trade Center collapse". Archived from the original on 2006-12-31.
  11. "CARC - UNC-Charlotte - Class 1000 Clean Room Facilities". ece.uncc.edu. Archived from the original on 12 September 2006.
  12. "Cell Phone Trees". waynesword.palomar.edu.
  13. "Today". marlaine.com.
  14. "Stealth towers". lightwatcher.com.
  15. "Telecom-equipped drones could revolutionize wireless market". azcentral.com.
  16. Shire, Gavin G.; Karen Brown; Gerald Winegrad (June 2000). "Communication Towers: A Deadly Hazard to Birds" (PDF). American Bird Conservancy. Earthjustice. Retrieved 2010-09-29.
  17. "Avian Collisions at Communication Towers - Sources of Information". U.S. Fish and Wildlife Service. June 1, 2009. Retrieved 2010-08-13.
  18. "Nesting falcon hits Vodafone customers in Southampton". BBC News. 15 April 2013. Retrieved 20 May 2013.
  19. Ray, Bill (17 April 2013). "Angry Birds fire back: Vulture cousins menace UK city's mobiles". The Register. Retrieved 20 May 2013.

Further reading