Radio masts and towers

Radio masts and towers are tall structures built to hold up antennas for sending and receiving messages and shows, like television. They help us talk to each other and watch shows from far away. There are two main kinds: ones that are held up by wires and ones that stand on their own. These towers are some of the tallest things people have ever built. Often, they are named after the companies that first built them or still use them today.

A special kind of tower is called a mast radiator. In this type, the whole tower is powered up and works like the antenna itself to send out signals. These towers are very important for making sure we can get the information and entertainment we need every day.

Terminology

The words "mast" and "tower" are often used to mean the same thing. But in building terms, a tower stands on its own, while a mast needs extra support with wires called guy-wires.

A mast is a guyed mast. It is a thin structure that cannot stand alone and uses wires called guy lines to stay steady. Masts can be placed on the ground or on top of buildings. They are usually made of steel and are cheaper to build, but they need extra space for the wires.

A tower is a structure that can stand by itself. It can also be placed on a building’s roof. Towers do not need extra space for wires, so they are often used in cities where space is limited.

There are some special designs that are a mix of both. For example:

The Gerbrandy tower has a tower that stands alone with a mast on top that needs wires for support.

The Blaw-Knox towers have a part that needs wires at the bottom and a part that stands alone at the top.

The Zendstation Smilde is a tall tower with a mast on top that uses wires to stay steady.

The Torre de Collserola is a tower that needs wires, and it also has a mast on top that needs wires.

History

See also: History of broadcasting

In the late 1800s, Guglielmo Marconi began testing ways to send radio communication signals. He learned that the higher he placed his antenna, the farther the signal could travel. Soon after, radio started being used for sending messages over long distances.

As radio technology grew, new types of antennas were developed. Early radio stations used big antennas made of wires between tall towers. Later, single masts were used, where the mast itself acted as the antenna. By the 1930s, a special tower design called the Blaw-Knox tower was used, but it had some problems with signal quality.

When FM radio and television broadcasting began in the 1940s and 1950s, even taller masts were needed. These newer signals could only travel straight lines, so taller towers helped send them farther.

Materials

Radio masts and towers are often made from different materials, each chosen for its strengths.

Steel lattice: Steel lattices are the most common type of construction. They are strong, light, and can resist wind well while using fewer materials. These structures can be built with triangular or square shapes. Some have supporting cables that help them stay steady in windy conditions.

Tubular steel, reinforced concrete, fiberglass, carbon fiber, and wood: Other materials like steel tubes, strong concrete, lightweight fiberglass, very strong carbon fiber, and even wood are also used. Each material has its own benefits, like looking cleaner, being very sturdy, or blending in with natural surroundings. Wood, for example, is now being used more because it helps the environment.

Other types of antenna supports and structures

Poles

Shorter towers can be made from wooden poles, much like old telegraph poles. Sometimes, metal poles made of galvanized steel are used instead. These can also be called monopoles.

Buildings

Sometimes, antennas are placed on the roofs of tall buildings. In North America, you can find antennas on famous buildings such as the Empire State Building, the Willis Tower, Prudential Tower, 4 Times Square, and One World Trade Center. In Europe, especially in London, antennas are also placed on buildings for radio and television broadcasts.

Disguised cell-sites

Some cell towers are designed to look like everyday objects, such as trees, chimneys, or water tanks. This helps them blend into the surroundings and not stand out as tall, bare towers. These hidden towers are called "stealth towers" or "concealed cell sites". They can even look like cacti in places like the Coronado National Forest in the United States.

Mast radiators

Main article: Mast radiator

A special kind of tower is called a mast radiator, where the entire tower acts as an antenna. These are often used for long or medium wave radio broadcasts.

Telescopic, pump-up and tiltover towers

Main article: Cell on wheels

Telescopic masts can be raised quickly and are often used for temporary radio links, like during news events or emergencies. There are two main types: pump-up masts, which are raised using air or fluid pressure, and telescopic lattice masts, which are raised using a winch. Some of these can even be lowered flat to the ground for easy transport and setup.

Balloons and kites

Sometimes, a balloon or a kite is used to hold an antenna high in the air. This method is used by the military or radio hobbyists. For example, a television program called TV Martí used a balloon to send signals to Cuba.

Drones

In 2013, people started exploring the use of drones for communication purposes.

Other special structures

See also: List of spans § Antenna spans across valleys

For very low frequency radio signals, wires are sometimes stretched across valleys and supported by small towers or anchors. For extremely low frequency signals, special antennas called ground dipoles are used, which don’t need tall towers at all.

Design features

Radio masts and towers are special tall structures that help hold up antennas for things like TV and phone signals. There are two main types: guyed masts, which have wires holding them up, and self-supporting towers. Building a guyed mast is usually cheaper, but it needs more space. Self-supporting towers take up less space but can cost more.

These structures sometimes have lights to warn airplanes, especially if they are very tall. There are rules about how tall they can be and what colors they need to be painted to stay safe. Sometimes, tall towers can be dangerous for birds, and there have been efforts to find ways to protect them.

Catastrophic collapses

Main article: List of catastrophic collapses of radio masts and towers

Some very tall radio masts and towers have fallen down in big accidents. These structures are important for sending TV and radio signals, but sometimes they can collapse because of strong winds, storms, or other problems. When this happens, it can affect many people who depend on those signals.