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 more limited sound quality than FM stations on the FM broadcast band. During the daytime, reception is usually limited to more local stations, though this is dependent on the signal conditions and quality of radio receiver used. Improved signal propagation at night allows the reception of much longer distance signals. This can cause increased interference because on most channels multiple transmitters operate simultaneously worldwide. In addition, amplitude modulation (AM) is often more prone to interference by various electronic devices, especially power supplies and computers. Strong transmitters cover larger areas than on the FM broadcast band but require more energy and longer antennas. Digital modes are possible but have not reached momentum yet.
The Warsaw Radio Mast was a radio mast located near Gąbin, Poland, and the world's tallest structure at 2,120 ft from 1974 until its collapse on 8 August 1991. The mast was designed for extreme height in order to broadcast Communist propaganda around the world, including to the remotest areas such as Antarctica. As of 2023, it was the third-tallest structure ever built, after the Burj Khalifa tower in the United Arab Emirates in 2009, and Merdeka 118 tower in Malaysia in 2022.
WLW is a commercial news–talk radio station licensed to Cincinnati, Ohio. Owned by iHeartMedia, WLW is a clear-channel station, often identifying itself as “The Big One”. Its studios are located in Sycamore Township.
A guyed mast or guyed tower is a tall thin vertical structure that depends on guy lines for stability. The mast itself has the compressive strength to support its own weight, but does not have the shear strength to stand unsupported. It requires guy lines to stay upright and to resist lateral forces such as wind loads. Guy lines are usually spaced at equal angles about the structure's base.
A guy-wire, guy-line, guy-rope, down guy, or stay, also called simply a guy, is a tensioned cable designed to add stability to a free-standing structure. They are used commonly for ship masts, radio masts, wind turbines, utility poles, and tents. A thin vertical mast supported by guy wires is called a guyed mast. Structures that support antennas are frequently of a lattice construction and are called "towers". One end of the guy is attached to the structure, and the other is anchored to the ground at some distance from the mast or tower base. The tension in the diagonal guy-wire, combined with the compression and buckling strength of the structure, allows the structure to withstand lateral loads such as wind or the weight of cantilevered structures. They are installed radially, usually at equal angles about the structure, in trios and quads. As the tower leans a bit due to the wind force, the increased guy tension is resolved into a compression force in the tower or mast and a lateral force that resists the wind load. For example, antenna masts are often held up by three guy-wires at 120° angles. Structures with predictable lateral loads, such as electrical utility poles, may require only a single guy-wire to offset the lateral pull of the electrical wires, at a spot where the wires change direction.
The Lakihegy Tower is a 314-metre-high (1,031 ft) radio mast at Szigetszentmiklós-Lakihegy in Hungary. The Blaw-Knox type tower was built in 1933 and was one of Europe's tallest structures at the time of construction. It was designed to provide broadcast coverage for Hungary with a 120 kW transmitter. It was built for the purpose of transmitting the radio station "Budapest I.", which it served until 1977.
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.
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.
The RKS Liblice 2 are two 355 m (1,165 ft) tall guyed masts located east of Prague near Liblice, in close proximity of the RKS Liblice 1. These lattice steel towers are built 120 m (390 ft) apart from each other, what formed a slightly directional radiation pattern directed towards Spanish Madrid transmitter on the same frequency. The masts carry a special anti-fading cage aerials. Designed by Jan Šťovíček, these supertall towers currently stand as the tallest towers in the world used for broadcasting in the medium-wave range. RKS Liblice-2 was built in 1976, and was used for broadcasting on 639 kHz until December 31st, 2021. During construction, two new transmitter devices of the type Tesla SRV 750 with an output power of 750 kW were installed. At first, these transmitters were switched in parallel for a transmission power of 1500 kW, after 1990 only 750 kW was used for broadcasting.
The Vakarel Transmitter was a large broadcasting facility for long- and medium wave near Vakarel, Bulgaria. The Vakarel Transmitter was inaugurated in 1937. It had one directional antenna consisting of three guyed masts and another consisting of two masts.
The folded unipole antenna is a type of monopole mast radiator antenna used as a transmitting antenna mainly in the medium wave band for AM radio broadcasting stations. It consists of a vertical metal rod or mast mounted over and connected at its base to a grounding system consisting of buried wires. The mast is surrounded by a "skirt" of vertical wires electrically attached at or near the top of the mast. The skirt wires are connected by a metal ring near the mast base, and the feedline feeding power from the transmitter is connected between the ring and the ground.
An umbrella antenna is a capacitively 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 MF, 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 wire frame of a giant umbrella hence the name.
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 or Sender Golm 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.
The Riga LVRTC Transmitter was a mediumwave transmitter in Ulbroka near Riga, Latvia, which broadcast on 945 kHz a music program in DRM-simulcast mode, which was receivable at night time in wide parts of Europe. It used as an antenna two guyed mast radiators. One of them was a 125 m-tall (410 ft) guyed lattice mast. The other smaller tower stays a Blaw-Knox Radiator. It is one of the few existing Blaw-Knox Radiators in Europe. Other towers of this type exist at Lisnagarvey, Northern Ireland, Lakihegy, Hungary, Vakarel, Bulgaria and Stara Zagora, Bulgaria.
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.
WFEA is a commercial AM radio station in Manchester, New Hampshire, airing a talk radio format. It is owned and operated by Saga Communications of New England LLC, which also owns 95.7 WZID and 96.5 WMLL. WFEA's studios and offices are on North Commercial Street in Manchester.
In radio systems, many different antenna types are used whose properties are especially crafted for particular applications. Antennas can be classified in various ways. The list below groups together antennas under common operating principles, following the way antennas are classified in many engineering textbooks.
