Satellite phone

A satellite telephone, satellite phone, or satphone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites. They provide similar functionality to terrestrial mobile telephones; voice, short messaging service and low-bandwidth internet access are supported through most systems.

Depending on the architecture of a particular system, coverage may include the entire Earth or only specific regions.

The mobile equipment, also known as a terminal, varies widely. Early satellite phone handsets had a size and weight comparable to that of a late-1980s or early-1990s mobile phone, but usually with a large retractable antenna. More recent satellite phones are similar in size to a regular mobile phone while some prototype satellite phones have no distinguishable difference from an ordinary smartphone. Satphones are popular on expeditions into remote areas where terrestrial cellular service is unavailable.

A fixed installation, such as one used aboard a ship, may include large, rugged, rack-mounted electronics, and a steerable microwave antenna on the mast that automatically tracks the overhead satellites. Smaller installations using VoIP over a two-way satellite broadband service such as BGAN or VSAT bring the costs within the reach of leisure vessel owners. Internet service satellite phones have notoriously poor reception indoors, though it may be possible to get a consistent signal near a window or in the top floor of a building if the roof is sufficiently thin. The phones have connectors for external antennas that can be installed in vehicles and buildings. The systems also allow for the use of repeaters, much like terrestrial mobile phone systems.