Transmission tower
In contrast to a transmission mast , a transmission tower is a tower structure designed as a free-standing structure that either serves to accommodate transmission antennas or directly as a transmission antenna ( self-radiating transmission tower ).
Construction forms
There are also constructions that consist of a free-standing tower on which a guyed transmission mast stands, so-called hybrid towers . However, such structures are very rare. Transmitting towers are either as a steel truss construction or designed as a reinforced concrete structure. In earlier years, wooden towers were also common, but today - with the exception of the transmission tower in Gleiwitz - they have completely disappeared.
Further embodiments are glass fiber constructions. They are sometimes implemented as transmission towers for NDBs or medium wave transmitters of low power.
A special form of the transmission tower is the telescopic mast , with the help of which an antenna carrier can be realized in a very short time. Telescopic masts are mainly used to set up radio links for reporting major events and to replace antenna supports destroyed by disasters.
A tethered balloon or kite can also be used for short-term implementation of an antenna carrier . On the one hand, he can carry a corresponding transmitting antenna, or on the other hand , hold an antenna wire (for VLF , LW or MW ) at an appropriate height. Such an arrangement is sometimes used by military agencies or radio amateurs. The American broadcaster Radio and TV Martí used a tethered balloon as a permanent broadcasting device, which broadcast a television program for Cuba using such a balloon, but has now broadcast it from a converted aircraft.
Transmission towers can be designed as a grounded or as an isolated construction. Insulated transmission towers are used as antennas for long and medium wave. However, such constructions are rather rare, since guyed transmission masts have better radiation properties. Well-known isolated transmission towers are the Berlin radio tower , the Blosenberg tower in Beromünster , the transmission towers in Junglinster or the Dobl transmitter in Styria. Transmission towers isolated from earth are never constructed as concrete towers due to the limited load capacity of the insulators.
Equipment of transmission towers
A suitable means of access must always be provided for access to components that require maintenance, such as antennas, guy guying, operating rooms or flight safety lights. In the case of small transmission towers and those where there are only a few facilities, this is usually implemented in the form of a fixed ladder that is attached both inside and outside the structure. For towers with a larger cross-section and requiring more frequent maintenance, a staircase and often an elevator are installed. This elevator is implemented as a conventional cable elevator for transmission towers in reinforced concrete construction. Elevators in free-standing steel lattice towers are occasionally and in guyed transmission masts are almost always implemented as climbing elevators for reasons of tower statics . In principle, elevator systems can also be installed in self-radiating transmission towers that are insulated from earth. However, this is usually not done because of the mostly small number of facilities that require maintenance and the rarity of their ascent, which either requires an interruption of the transmission operation or has to be done via special isolated platforms.
Transmission towers that have other installations in addition to radio equipment, such as water supply systems or tourist facilities, always have a staircase and in almost all cases an elevator. As a rule, however, the tourist cannot choose between the stairwell and the elevator.
Grounded transmission towers made of steel and concrete are often used to accommodate transmission antennas in the VHF range and directional radio antennas . Occasionally they are also used to hold wire antennas for longitudinal, long and medium wave, as well as support towers of dipole walls for short wave directional radiators (in this application almost always as a steel tower). Concrete towers are mostly used to support transmitting antennas for VHF radio, television, directional radio and cellular radio . Smaller towers are often composed of precast concrete parts, while larger towers are usually made of in- situ concrete .
Special form of the television tower
Some transmission towers - in particular those for directional radio in concrete construction - have a high-level operating room accessible via an elevator to accommodate transmission devices. In other cases, the transmitters are located in a building next to the transmission tower. In the case of VHF transmission systems, this is usually immediately next to the transmission tower, in the case of transmitters for long, medium and short wave, for radiation-related reasons, this is usually at a distance of 30 to 600 meters. Instead, in these cases there is a little house with the tuning elements of the resonance transformer next to (or under) the transmission tower, the so-called tuning house . In some towers, instead or in addition, there are high-altitude rooms with tourist facilities, such as a viewing platform and a tower restaurant .
Such towers are usually referred to as television towers , even if they are not used to broadcast television programs. There are also transmission towers that are also used as water towers, such as the television tower in Heidelberg .
Construction work
The type of construction of a transmission tower or whether a guyed transmission mast should be used instead of a free-standing tower depends on many factors. For transmission systems for frequencies below 3 MHz, the guyed transmission mast is usually preferred - either isolated from the ground, with a trap antenna or top feed . Nowadays, a reinforced concrete tower is almost always used for transmission towers with tourist facilities. In Germany, this also applies to radio relay systems , since concrete towers fluctuate less than steel towers when the wind is the same. For other transmission towers with pure VHF and directional radio applications, the choice of the type of antenna carrier is not always comprehensible, as the aesthetic appearance of the construction and offers from the corresponding companies sometimes play a role.
The guyed transmission mast is usually used for very tall structures (see also the list of the tallest structures in the world ). In some cases it is possible to mount transmitting antennas for radio services in the VHF range on the roofs of tall buildings. This is often used in North America in particular (transmission antennas on the Empire State Building or the Sears Tower ), but such systems are also quite common in Europe, especially for cellular services and low-power VHF transmitters.
Also pylons can possibly serve to accommodate transmission antennas. Mostly these are cellular antennas or directional antennas of the respective energy supply company . However, other systems have also been installed, such as a radar system from the Hamburg Waterways and Shipping Office on a mast at Elbe crossing 1 .
High transmission towers must be equipped with flight safety lights. Feeding them is not a problem with earthed constructions. In the case of isolated towers, the power is supplied via a cable laid in a choke coil which, if necessary with a capacitor connected in parallel, forms a blocking circuit for the transmission frequency and which is connected between the tower and earth.
Collapse of transmission towers and transmission masts
Transmission towers and transmission masts collapsed again and again, be it due to natural events such as storms, fire as a result of renovation work or sabotage / terrorist attacks. (Please complete list)
| place | date | Design of the transmission mast | height | Cause of misfortune | Remarks |
|---|---|---|---|---|---|
| Nauen , Germany | March 30, 1912 | guyed steel truss mast | 200 m | Storm | |
| Norddeich Mole , Germany | November 25, 1925 | guyed steel truss mast | ? | Storm | 3 transmission masts affected |
| Transmitter Magdeburger Platz, Berlin, Germany | July 1926 | Guyed steel framework mast on the house roof | ? | rusty pardune | |
| western transmitter mast of Zeesen transmitter , Germany | 1927 | guyed steel truss mast | 210 m | Collapse during construction | |
| Munich- Stadelheim , Germany | November 23, 1930 | freestanding wooden tower | 75 m | Storm | 2 towers affected, bent at a height of approx. 25 meters |
| Langenberg , Germany | October 10, 1935 | free-standing timber lattice tower | 150 m | Windpants | replaced by a triangular antenna |
| Liechtenstein-Haberfeld transmitter | November 21, 1938 | Foehn storm | |||
| Utbremen transmission tower | 1939 | free-standing timber lattice tower | 90 m | lightning strike | replaced by steel tower |
| western tower of the Fécamp transmitter of Radio Normandie | November 7, 1940 | free-standing steel lattice tower | 113 m | Storm | [1] |
| Langenberg , Germany | 1949 | guyed tubular steel mast | 51 m | Storm | 2 masts of a triangular antenna destroyed |
| Transmitter mast Schwerin-Möwenburgstrasse, Schwerin, Germany | February 10, 1949 | guyed steel truss mast | 120 m | Storm | |
| Hamburg-Billwerder , Germany | December 1949 | guyed steel truss mast | 198 m | Storm | partial destruction of a transmission tower under construction |
| WOAI , Selma (San Antonio), USA | 1957/1958 | guyed steel truss mast | 50 m | Plane collision | |
| Ochsenkopf , Germany | January 1958 | guyed tubular steel mast | 50 m | icing | replaced by reinforced concrete tower |
| KOBR transmission mast , Caprock, New Mexico, USA | 1960 | guyed steel truss mast | 490.7 m | Storm | Replacement by new construction of the same height |
| LORAN-C transmission tower Carolina Beach , Carolina Beach, USA | 1961 | free-standing steel lattice tower | 190.5 m | Storm | Tower had roof capacity, although not designed for it |
| Transmission tower Villebon-sur-Yvette , France | December 10, 1961 | guyed steel truss mast | ? | Terrorist attack | |
| LORAN-C transmitter mast Ejde , Ejde, Faroe Islands | 1962 | guyed steel truss mast | 190.5 m | Material defect | |
| LORAN-C transmission tower Angissq , Angissq, Greenland | August 1964 | guyed steel truss mast | 411.48 m | Material defect | A defective bolt in a tensioning insulator led to the collapse, replacement with a 214-meter-high transmitter mast |
| LORAN-C transmission tower Yap , Yap, Micronesia | 1964 | guyed steel truss mast | 304.8 m | Collapse during construction | |
| LORAN-C transmission tower Iwo Jima, Japan | 1965 | Guyed steel framework mast | 411.48 m | Maintenance work | collapsing mast also destroyed the transmitter building, 6 dead |
| KXJB TV mast , North Dakota, USA | February 14, 1966 | guyed steel truss mast | 627.89 m | Helicopter collision | |
| WNBC / WCBS Tower, High Island, New York, USA | August 27, 1967 | guyed steel truss mast | 161 m | Plane collision | |
| Waltham television broadcast tower, Melton Mowbray, Leicestershire, UK | 1967 | guyed tubular steel mast | 290 m | ? | |
| KELO transmission mast , Rowena, South Dakota, USA | 1968 | guyed steel truss mast | 609.6 m | Plane collision | |
| WAEO Tower , Starks, Wisconsin, USA | 17th November 1968 | guyed steel truss mast | 524.25 m | Plane collision | |
| Marnach , Luxembourg | 17th January 1969 | ? | 220 m | ? | |
| Emley Moor , UK | March 19, 1969 | guyed steel truss mast | 385 m | icing | |
| Long wave transmitter Orlunda , Sweden | July 12, 1970 | guyed steel truss mast | 250 m | Lightning strike (destruction of the base point insulator) | |
| KOIN TV station in Portland, Oregon, USA | February 28, 1971 | Guyed steel truss masts | 304.8 m and 213.4 m | icing | two masts collapsed |
| Koenigs Wusterhausen , Germany | November 15, 1972 | free-standing steel tower | 243 m | Storm | |
| ?, City of Kennett, USA | 1973 | ? | 21.33 m | ? | |
| Brest-Roc Trédudon transmitter mast | February 1974 | guyed steel truss mast | 220 m | attack | |
| KELO transmission mast , Rowena, South Dakota, USA | 1975 | guyed steel truss mast | 609.6 m | Blizzard | |
| Droitwich transmitter , UK | 2nd January 1976 | guyed steel truss mast | ? | Storm | |
| Transmission mast SL3, Burg , Germany | 18th February 1976 | guyed steel truss mast | 350 m | Material defect | |
| Broadcasting station Pic de Nore , Pradelles-Cabardès , France | 2nd December 1976 | Reinforced concrete tower | ? | Storm | Tip broken off; replaced by a new tower |
| KSLA transmission mast, USA | 1977 | guyed steel truss mast | 521 m | ? | |
| Nebraska Education Transmitter Tower Angora, Angora, Nebraska, USA | February 1978 | guyed steel truss mast | 456.9 m | icing | |
| WJJY-TV transmission mast , Bluffs, Illinois, USA | March 26, 1978 | guyed steel truss mast | 491 m | icing | |
| WJJY-TV transmission mast , Bluffs, Illinois, USA | March 26, 1978 | guyed steel truss mast | 491 m | icing | |
| WALL TV mast , Decatur, IL USA | March 26, 1978 | guyed steel truss mast | 400.5 m | icing | |
| Zehlendorf , Germany | May 21, 1978 | guyed steel truss mast | 352 m | Plane collision | |
| CKVR television broadcast tower, Barrie, Ontario, Canada | 1978 | ? | 65.58 m | Plane collision | |
| Vysílač Krašov , Bezvěrov, Czech Republic | 1979 | guyed steel truss mast | 305 m | icing | Mast was previously damaged |
| Blåbärskullen , Sunne, Sweden | December 27, 1979 | guyed steel truss mast | 323 m | icing | Tip with transmitting antennas bent, today's height 274 meters |
| LORAN-C transmission mast Jan Mayen , Jan Mayen, Norway | October 8, 1980 | guyed steel truss mast | 190.5 m | icing | |
| Cyclops relay station | ? | guyed steel truss mast | 88 m | a guy rope melted as a result of the high electrical field strength, and a storm that occurred at the same time caused the mast to collapse | |
| Dudelange transmission tower | July 31, 1981 | free-standing steel lattice tower | 285 m | Plane collision | A Belgian Mirage collided with the transmission tower, the pilot and two people on the ground died |
| Senior Road Tower , Missouri City , Texas, USA | 1982 | guyed steel truss mast | ? | ? | |
| ?, UNITED STATES | 1982 | guyed steel truss mast | 305 m | ? | |
| Wavre , Belgium | October 13, 1983 | guyed transmitter mast | ? | Storm | |
| CKX TV transmission tower , Canada | 1983 | guyed transmitter mast | 411.5 m | icing | |
| Bielstein (Teutoburg Forest, near Hermannsdenkmal) | Bielstein, Germany 51 ° 54 '20 "N, 08 ° 49' 20" E | January 15, 1985 | Guyed tubular steelwork mast | 298 m | At 6:26 a.m., the icy transmitter mast collapsed and was completely destroyed. The tearing off of a strap that was weakened by a fatigue crack and that connected one of the upper guy ropes to the mast led to the accident at night. | In September 1986 the new 302 meter high (since April 2006, 298 meter) transmission mast was completed. |
| Radio Caroline & Radio Monique mast on board MV Ross Revenge, off the English coast | November 25, 1987 | Steel framework mast | approx. 92 m | Storm | highest mast ever erected on a ship; was replaced by a horizontal wire antenna between two shorter masts |
| Vännäsmasten , Vännäs , Sweden | 1987/88 | guyed steel framework mast? | ? m | icing | Replacement with a 323 meter high hybrid tower |
| ?, Missouri, USA | 1988 | guyed steel truss mast | 609.6 m | ? | |
| Auburn , North Carolina, USA | December 1989 | guyed steel truss mast | 609.3 m | icing | |
| Konstantynów transmission tower , Poland | August 8, 1991 | guyed steel truss mast | 648.38 m | Maintenance work | was new plant in Solec Kujawski replaced |
| WCIX transmission tower, Homestead, Florida, USA | 1992 | guyed steel truss mast | 609 m | Hurricane Andrew | |
| COMMSTA Miami, Miami, Florida, USA | 1992 | guyed steel truss mast | 91.44 m | Hurricane Andrew | 2 masts collapsed |
| LORAN-C transmitter mast Cape Race , Cape Race, Canada | 2nd February 1993 | guyed steel truss mast | 411.48 m | defective bolt in a guy insulator led to the collapse | |
| LORAN-C Transmitter Mast Kargaburan , Kargaburan, Turkey | February 25, 1993 | guyed steel truss mast | 190.5 m | Snowstorm | |
| WCOV transmission tower, Montgomery, USA | 1996 | ? | 242 m | tornado | |
| Langenberg , Germany | September 2, 1996 | guyed steel truss mast | 160 m | Maintenance work | |
| Channel 39 KXTX transmission tower, Cedar Hill, Texas, USA | October 12, 1996 | guyed steel truss mast | 468 m | Maintenance work | 3 workers were killed when the tower collapsed during a moderate gust of wind |
| ?, UNITED STATES | December 31, 1996 | ? | 195.1 m | Material defect | |
| KNOE transmission tower , Louisiana , USA | March 20, 1997 | guyed steel truss mast | 606.25 m | Maintenance work | 1 dead, 2 injured after workers failed to install makeshift bracing |
| Transmitter Grigoripol, Moldova | 1997 | guyed steel truss mast | 350 m, 250 m | icing | 2 masts collapsed [2] |
| KXJB TV mast , North Dakota, USA | April 6, 1997 | guyed steel truss mast | 627.89 m | icing | |
| WLBT-TV transmission mast , Mississippi, USA | October 23, 1997 | guyed steel truss mast | 609.3 m | Material defect | |
| WKY transmission mast, USA | June 13, 1998 | guyed steel truss mast | 292.9 m | tornado | |
| Avala TV tower , Serbia | April 30, 1999 | Reinforced concrete tower (with viewing platform) | 202.87 m | US bombing raid | |
| WMRD transmission tower, Saint Petersburg, Florida, USA | April 2000 | guyed steel truss mast | 207.3 m | ? | |
| WNWI 1080 transmission tower, Oak Lawn (Chicago), Illinois, USA | July 9, 2000 | guyed steel truss mast | 61 m | sabotage | two masts collapsed |
| KXEO / KWWR transmission mast, Mexico, MO, USA | August 23, 2000 | guyed steel truss mast | 122.8 m | Storm | |
| CBC transmission tower, Shawinigan, Quebec, Canada | April 22, 2001 | guyed steel truss mast | 371 m | blown up after plane collision | |
| North mast of the Angara radio station, Angara, Russia | June 6, 2001 | guyed steel truss mast (support mast of a T-antenna) | 205 m | poor condition of the guy ropes | |
| Broadcasting station Krasny Bor , Krasny Bor, Russia | November 5, 2001 | guyed steel truss mast | 257.5 m | Helicopter collision | |
| ?, Hemingford, Nebraska, USA | 2002 | guyed steel truss mast | 609.6 m | Maintenance work | |
| WVAH transmission tower, Scott Depot, West Virginia, USA | February 19, 2003 | guyed steel truss mast | 473 m | icing | |
| WPAY FM transmission tower, Portsmouth, Ohio, USA | February 19, 2003 | guyed steel truss mast | 200.9 m | icing | |
| WMBD transmission tower, Peoria, Illinois, USA | May 10, 2003 | free-standing steel lattice tower | ? | tornado | 3 towers affected |
| KETV-TV transmission tower, Omaha, Nebraska, USA | July 2003 | guyed steel truss mast | 415.1 m | Renovation works | |
| Utrecht, Netherlands | September 8, 2003 | guyed steel truss mast | 45 m | felled when felling trees | |
| KDUH / CH4 TV transmission mast, Hemingford, Nebraska, USA | September 24, 2003 | guyed steel truss mast | 599 m | Maintenance work | |
| Peterborough , UK | October 30, 2004 | guyed steel truss mast | 163 m | Fire | |
| KFID mast, Los Angeles , USA | December 19, 2004 | guyed transmitter mast | 195.1 m | Plane collision | |
| Torre VIP de Rádio & TV, São Bernardo do Campo, Brazil | August 23, 2006 | guyed transmitter mast | 174 m | Maintenance work | 1 person was killed |
| KATV transmission tower , Redfield, Arkansas, USA | January 11, 2008 | guyed transmitter mast | 609.6 m | Maintenance work (replacement of guy ropes) | |
| Freinberg , Linz, Austria | before April 2008 | guyed transmitter mast | Crack in the support insulator at the base of the mast was discovered and splinted quickly, no collapse; Mast was exchanged in 2008 | ||
| WEAU-TV / WAAX-FM transmission tower , Fairchild, Wisconsin, USA | March 22, 2011 | guyed transmitter mast | 609.6 m | icing | |
| Smilde transmission tower , Hoogersmilde, Drenthe , Netherlands | July 15, 2011 | Concrete tower (height 80 m) with guyed transmitter mast on top | 303.5 m | Fire in the transmitter mast | Collapse of the steel transmission mast, the concrete tower was damaged, but remained standing |
| Transmitter Felsberg-Berus , Felsberg-Berus, Germany | August 8, 2012 | guyed transmitter mast | 280 m | ? | Tip kinked |
| Umsetzer Boll, Oberndorf-Boll, Germany | November 2, 2012 | free-standing steel lattice tower | 30 m | Collision with truck [3] |
