Microwave transmission in the context of "Line of sight"

A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for information transfer of, for example, a digital bit stream, from one or several senders to one or several receivers. A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second.

Communicating an information signal across distance requires some form of pathway or medium. These pathways, called communication channels, use two types of media: Transmission line-based telecommunications cable (e.g. twisted-pair, coaxial, and fiber-optic cable) and broadcast (e.g. microwave, satellite, radio, and infrared).

A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity. It functions similarly to a searchlight or flashlight reflector to direct radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest gains, meaning that they can produce the narrowest beamwidths, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the wavelength of the radio waves used, so parabolic antennas are used in the high frequency part of the radio spectrum, at UHF and microwave (SHF) frequencies, at which the wavelengths are small enough that conveniently sized reflectors can be used.

Parabolic antennas are used as high-gain antennas for point-to-point communications, in applications such as microwave relay links that carry telephone and television signals between nearby cities, wireless WAN/LAN links for data communications, satellite communications, and spacecraft communication antennas. They are also used in radio telescopes.

The public switched telephone network (PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. It provides infrastructure and services for public telephony. The PSTN consists of telephone lines, fiber-optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables interconnected by switching centers, such as central offices, network tandems, and international gateways, which allow telephone users to communicate with each other.

Originally a network of fixed-line analog telephone systems, the PSTN is now predominantly digital in its core network and includes terrestrial cellular, satellite, and landline systems. These interconnected networks enable global communication, allowing calls to be made to and from nearly any telephone worldwide. Many of these networks are progressively transitioning to Internet Protocol to carry their telephony traffic.

A low-noise block downconverter (LNB) is the receiving device mounted on satellite dishes used for satellite TV reception, which collects the radio waves from the dish and converts them to a signal which is sent through a cable to the receiver inside the building. Also called a low-noise block, low-noise converter (LNC), or even low-noise downconverter (LND), the device is sometimes inaccurately called a low-noise amplifier (LNA).

The LNB is a combination of low-noise amplifier, frequency mixer, local oscillator and intermediate frequency (IF) amplifier. It serves as the RF front end of the satellite receiver, receiving the microwave signal from the satellite collected by the dish, amplifying it, and downconverting the block of frequencies to a lower block of intermediate frequencies (IF). This downconversion allows the signal to be carried to the indoor satellite TV receiver using relatively cheap coaxial cable; if the signal remained at its original microwave frequency it would require an expensive and impractical waveguide line.

Home Box Office (HBO) is an American premium television network and service, which is the flagship property of namesake parent-subsidiary Home Box Office, Inc., itself a unit owned by Warner Bros. Discovery. The overall Home Box Office business unit is based at Warner Bros. Discovery's corporate headquarters inside 30 Hudson Yards in Manhattan. Programming featured on the service consists primarily of theatrically released motion pictures and original television programs as well as made-for-cable movies, documentaries, occasional comedy, and concert specials, and periodic interstitial programs (consisting of short films and making-of documentaries).

HBO is the oldest subscription television service in the United States still in operation, as well as the country's first cable-originated television content service (both as a regional microwave- and national satellite-transmitted service). HBO pioneered modern pay television upon its launch on November 8, 1972: it was the first television service to be directly transmitted and distributed to individual cable television systems, and was the conceptual blueprint for the "premium channel", pay television services sold to subscribers for an extra monthly fee that do not accept traditional advertising and present their programming without editing for objectionable material. It eventually became the first television channel in the world to begin transmitting via satellite—expanding the growing regional pay service, originally available to cable and multipoint distribution service (MDS) providers in the northern Mid-Atlantic and southern New England, into a national television service—in September 1975, and, alongside sister channel Cinemax, was among the first two American pay television services to offer complimentary multiplexed channels in August 1991.

Telecommunications engineering is a subfield of electronics engineering which seeks to design and devise systems of communication at a distance. The work ranges from basic circuit design to strategic mass developments. A telecommunication engineer is responsible for designing and overseeing the installation of telecommunications equipment and facilities, such as complex electronic switching system, and other plain old telephone service facilities, optical fiber cabling, IP networks, and microwave transmission systems. Telecommunications engineering also overlaps with broadcast engineering.

Telecommunication is a diverse field of engineering connected to electronic, civil and systems engineering. Ultimately, telecom engineers are responsible for providing high-speed data transmission services. They use a variety of equipment and transport media to design the telecom network infrastructure; the most common media used by wired telecommunications today are twisted pair, coaxial cables, and optical fibers. Telecommunications engineers also provide solutions revolving around wireless modes of communication and information transfer, such as wireless telephony services, radio and satellite communications, internet, Wi-Fi and broadband technologies.

India's telecommunication network is the second largest in the world by number of telephone users (both fixed and mobile phones) with over 1.19 billion subscribers as of September 2024. It has one of the lowest call tariffs in the world enabled by multiple large-scale telecom operators and the ensuant hyper-competition between them. India has the world's second largest Internet user-base with over 949.21 million broadband internet subscribers as of September 2024.

Major sectors of the Indian telecommunication industry are the telephone, internet and television broadcast industries in the country which are involved in an ongoing process of developing into a next-generation network, increasingly employing an extensive array of modern network infrastructure such as digital telephone exchanges, network switching subsystems, media gateways and signaling gateways at the core, interconnected by a wide variety of transmission systems using optical fiber or microwave radio relay networks. The access network, which connects the subscriber to the core, is highly diversified with different copper-pair, optical fiber and wireless technologies. Satellite television, a relatively new broadcasting technology has attained significant popularity in the Television segment. The introduction of private FM has boosted radio broadcasting in India. Telecommunication in India has been greatly supported by the Indian National Satellite System system of the country, one of the largest domestic satellite systems in the world. India possesses a diversified communications system, which links all parts of the country by telephone, Internet, radio, television and satellite. India's participation in global telecommunications and spectrum policy discussions is supported by the ITU-APT Foundation of India (IAFI), a sector member of ITU-R, ITU-T, and ITU-D.