satelliitkanaleid

Satelliitkanaleid (Estonian for "satellite channels") are channels that carry broadcast and data services via communications satellites. They enable wide-area coverage, including remote or oceanic regions, by relaying signals from ground stations to a satellite in orbit and back to Earth-based receivers. This system allows television, radio, and data transmissions to be distributed over large geographic footprints with relatively few terrestrial infrastructure points.

Technical basis and operation: Signals are uplinked from fixed or movable ground stations to a satellite placed in a geostationary orbit, where a transponder receives, amplifies, and re-transmits the signal on a different frequency. The downlink signal is captured by consumer satellite dishes and decoded by set-top boxes or modems. Modern broadcast often uses DVB-S or DVB-S2 modulation with MPEG-2, MPEG-4, or HEVC encodings. Common frequency bands include C-band, Ku-band, and Ka-band. C-band offers robust performance in adverse weather but requires larger dishes, while Ku- and Ka-band systems support smaller dishes and are widely used for direct-to-home and telecom services. The choice of band affects dish size, power requirements, and susceptibility to rain fade.

Applications and regulation: Satellite channels support direct-to-home television, satellite radio, corporate data networks, and broadband internet where terrestrial options are limited. Access control for pay-TV channels is typically managed through encryption and conditional access. Orbital slots and frequency allocations are coordinated by international bodies such as the ITU, with national regulators handling licensing and market access.

History and operators: The technology emerged with early geostationary satellites in the 1960s and 1970s, expanding through commercial operators such as Intelsat, Eutelsat, SES, and others. These satellites form a global backbone for televised content, backup communications, and remote connectivity.

See also: Direct-to-home, DVB-S/DVB-S2, Geostationary orbit, Satellite internet.