Satellite radio ( Eng. Satellite radio ) - a digital radio broadcasting using a communications satellite . Satellite radio is also called radio stations that are part of a digital television multiplex transmitted via satellite. They can be listened to using a digital television receiver after tuning by switching it to radio mode; You can connect to the receiver, instead of the TV, an external amplifier with speakers. There is also an automotive satellite radio system described below.
The advantage of satellite radio is that it covers a larger geographical area than the signals of conventional ( VHF / FM ) radio stations , providing high sound quality and many additional services. Satellite radio operates in any place where there is direct visibility between the receiving antenna and the broadcasting satellite (except in cases of serious obstacles, such as a tunnel or building) - the listener has the opportunity to listen to any channel throughout the coverage area.
Since the technology requires the use of a commercial satellite for signal propagation, satellite radio services are provided by commercial companies and are provided in the form of packets (sets) of various channels that are provided for a monthly fee .
Currently, satellite radio is provided by the following companies: WorldSpace in Europe , Asia and Africa , Sirius XM Radio in North America (contains two networks after the merger). All companies use closed and incompatible signals, which require their own equipment for decoding and playback. Companies provide news, weather, sports, and several music channels.
Content
Technology
For satellite radio, the frequency is 2.3 GHz in the S-band in North America , and also partially 1.4 GHz in the L-band (DAB band, i.e. digital radio ). The so-called direct satellite broadcasting is used . The received signal is strong enough to use the small built-in satellite dishes to receive it. The spherical shape of the Earth limits the propagation of the signal, but the satellite’s orbit makes two or three satellites sufficient to cover the entire continent .
A local repeater , similar in function to the amplifier of a broadcasting transmitter, makes it possible to receive a signal even in places where there is no direct visibility with a satellite, for example, behind a skyscraper in a big city. Large tunnels may also have repeaters. Repeaters also allow you to broadcast local channels, such as information about traffic jams or weather, but this is not currently implemented.
Each receiver has an ESN (electronic serial number) - a unique identifier that identifies each device. When the device is activated, after subscribing to the software package, a special authorization code is sent in the digital broadcast stream, which tells the receiver to open access to paid channels. Most companies have at least one free channel ( en: free to air or “in the clear”, ITC) that can be used for testing.
Most (if not all) of the existing satellite radio broadcasting systems are closed (not using a common standard) and use different codecs for encoding audio information , different types of modulation , as well as various encryption and access control methods for channels.
Like many radio stations, satellite radio simultaneously transmits transmission data with the name of the author and the name of each song or program (similar to RDS ) and, possibly, the name of the channel.
USA and Canada
In the US and Canada, one holding company, Sirius XM Radio , operates on two satellite radio networks after the merger (XM acquired by Sirius in July 2008). Both services are provided only by subscription. XM uses geostationary satellites with a fixed position, and Sirius uses geosynchronous satellites in the highly elliptical orbit of the Tundra passing through the North and South American continents. Roughly speaking, the difference is that the signal from Sirius has a larger angle in the northern part of the USA, and even more in Canada. (A larger angle can cause signal loss in cities and, especially, in garages, tunnels and other indoor structures).
Both services are available mainly in receivers in cars, but both provide a choice of equipment that makes it possible to listen to them on home equipment, portable devices and through the Internet on a computer.
One of the main advantages of satellite radio is the fact that it is not localized: drivers can receive the same programs anywhere in the service coverage (the popularity of the Sirius XM radio among truckers will prove to you stopping at any parking of heavy vehicles). In addition, both satellite services can transmit something that is simply impossible to transmit to regular commercial radio stations: specialized channels can include such things as discussions of family relationships, radio plays, classical music or live broadcasts.
The coverage area for both services is mainly the United States (including Alaska ), Canada, and northern Mexico .
The future of satellite radio in Russia
On March 10, 2011, a meeting of the State Commission on Radio Frequencies was held under the chairmanship of the Minister of Telecom and Mass Communications of the Russian Federation Igor Shchegolev. The course of implementation of measures for the conversion of the radio frequency spectrum for 2010 and plans for 2011 were examined in detail. In the course of the work, the question of using the radio frequency band 2350–2360 MHz for the development and creation in Russia of satellite direct digital audio broadcasting (STZV) systems was considered. A source
See also
- Satellite television
Links
- Orbitcast.com - All Things Satellite Radio
- GetSiriusInfo.com Source for SIRIUS news and info
- [1] Digital Insurrection Satellite Radio Info
- Getting Satellite Radio One subscriber's easy how-to guide
- Digital Home Canada Canadian Satellite Radio Information and Discussion forums.
USA and Canada
- XM Satellite Radio XM Satellite Radio (owned by Sirius XM Radio)
- Sirius Satellite Radio Sirius Satellite Radio
Asia, Africa and Europe
- 1worldspace company