Fermi and Swift see 'shockingly bright' burst

A record-setting blast of gamma rays from a dying star in a distant galaxy has wowed astronomers around the world. The eruption, which is classified as a gamma-ray burst, or GRB, and designated GRB 130427A, produced the highest-energy ...

GPS Jamming Devices Pose Many Threats (w/ Video)

(PhysOrg.com) -- The latest GPS jamming devices are now being used by car thieves in the UK to render stolen cars and trucks undetectable by law enforcement. These devices also pose a threat to airlines and US military overseas.

Astronomers discover a new black hole in our galaxy

(Phys.org)—NASA's Swift satellite recently detected a rising tide of high-energy X-rays from a source toward the center of our Milky Way galaxy. The outburst, produced by a rare X-ray nova, announced the presence of a previously ...

Students develop an affordable everyday radio telescope

(Phys.org)—A team of undergraduates from the Indian Institute of Science Education and Research (IISER) at the College of Engineering in Trivandrum, India, has designed and constructed a portable college-level radio telescope ...

Watch a real-time map of Starlink satellites orbiting Earth

In an effort to enhance the educational outreach of Starlink constellation, an interactive global map of SpaceX Starlink internet satellites provides live coverage of every satellite in orbit around the Earth.

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Satellite radio

A satellite radio or subscription radio (SR) is a digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than terrestrial radio signals.

For now, satellite radio offers a meaningful alternative to ground-based radio services in some countries, notably the United States. Mobile services, such as Sirius, XM, and Worldspace, allow listeners to roam across an entire continent, listening to the same audio programming anywhere they go. Other services, such as Music Choice or Muzak's satellite-delivered content, require a fixed-location receiver and a dish antenna. In all cases, the antenna must have a clear view to the satellites. In areas where tall buildings, bridges, or even parking garages obscure the signal, repeaters can be placed to make the signal available to listeners.

Radio services are usually provided by commercial ventures and are subscription-based. The various services are proprietary signals, requiring specialized hardware for decoding and playback. Providers usually carry a variety of news, weather, sports, and music channels, with the music channels generally being commercial-free.

In areas with a relatively high population density, it is easier and less expensive to reach the bulk of the population with terrestrial broadcasts. Thus in the UK and some other countries, the contemporary evolution of radio services is focused on Digital Audio Broadcasting (DAB) services or HD Radio, rather than satellite radio.

This text uses material from Wikipedia, licensed under CC BY-SA