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Terrestrial television

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Terrestrial television, often called over-the-air (OTA) or broadcast television, is a method of transmitting video and audio content via radio waves. These waves travel from an Earth-based transmitter at a TV station to a receiver equipped with an antenna.

Rabbit-ears dipole antenna with UHF loop 20090204
Rabbit-ears dipole antenna with UHF loop 20090204

This technology differs significantly from other delivery methods. Satellite television, or direct broadcast satellite (DBS), receives signals from overhead satellites. Cable television delivers content through physical wires. Internet Protocol television (IPTV) uses internet streams or networks. Terrestrial broadcasting remains a foundational technology for global media distribution.

The mechanism of terrestrial television relies on specific electromagnetic frequencies. Stations broadcast on channels within the Very High Frequency (VHF) and Ultra High Frequency (UHF) bands. These bands typically range from about 52 to 600 MHz. Because these radio waves travel by line of sight, reception is usually limited by the visual horizon. However, special atmospheric conditions known as tropospheric ducting can sometimes allow signals to travel hundreds of kilometers.

Antenna
Antenna

In some regions, free-to-air repeaters or signal boosters are used to rebroadcast signals. These devices use unused channels to extend coverage to areas with marginal reception.

Television broadcasting has evolved through several distinct technological stages. The earliest era used mechanical scan technology, which produced insufficient picture quality for widespread public use. Following World War II, the advent of electronic scan technology allowed television to become a common household item. For many years, broadcasts were limited to greyscale, commonly called black and white. This changed in the 1960s with the transition to color television. Later, the industry moved from analog signals to digital terrestrial television (DTT), which uses digital data rather than continuous waves.

History shows that terrestrial television was the first broadcasting technology. The BBC began broadcasting in 1929, and by 1930, many radio stations aired experimental television programs. In Asia, experiments began in Japan as early as 1939 through the NHK Broadcasting Institute of Technology. Although World War II interrupted these efforts, NHK began regular broadcasting in 1953. That same year, Nippon TV became Asia's first commercial broadcaster. In the Philippines, the Alto Broadcasting System launched the first commercial station in Southeast Asia in October 1953.

Different regions developed unique technical standards to manage their broadcasts. In the Americas and Japan, the National Television System Committee (NTSC) standard was used for decades. The NTSC originally defined a black-and-white system with 525 lines of vertical resolution. In Europe, many countries utilized the PAL color system. The United Kingdom transitioned from its old 405-line VHF system to UHF broadcasts in 1964. Recently, many nations have moved to the Digital Video Broadcasting—Terrestrial (DVB-T) standard. For example, the European Union decided in 2005 to cease all analog transmissions by 2012.

North America has largely adopted the Advanced Television Systems Committee (ATSC) standards for digital high-definition transmission. In the United States, the FCC set a final deadline for the analog switch-off on June 12, 2009. Canada followed with a deadline of August 31, 2011, for metropolitan areas. Mexico discontinued its analog terrestrial service on December 31, 2015. A newer standard, ATSC 3.0, launched in select U.S. markets in 2020. This IP-based system is not backward compatible with the older ATSC 1.0 standard. However, it supports advanced features like 4K UHD resolution and immersive audio.

Despite the rise of internet streaming, terrestrial television remains globally significant. As of 2020, an estimated 1.6 billion people worldwide receive television through terrestrial means. Indonesia represents the largest market, with approximately 250 million viewers. In the United States, while many use cable or streaming, about 14% of households still use an antenna. This technology connects to broader digital systems through modern standards. For instance, ATSC 3.0 allows for hybrid broadcast-broadband services. This creates a connection between traditional broadcasting and interactive internet-like features.

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