Satellite Radio

http://www.timboucher.com

Satellite radio is a digital radio that uses communications satellite which covers a lot greater range than terrestrial radio signals. It is strong enough not to need a satellite dish to receive but does require an antenna, which must have a clear view to the satellites (‘repeaters’ can be used in tall buildings, bridges or parking garages). Thanks to that you can enjoy the same program independent where you go (assuming you stay on the same continent, due to Earth being round you would need around 2 or 3 satellites to cover the whole planet). Pretty much meaning that you don’t have to change the radio every hour or so scanning through the hiss like you do with your regular FM radio. The material is beamed up via a centralized hub to one of the networked satellite and from there either straight to your radio receiver or to the ground repeaters. Satellite radios are the main providers of background music in hotels, retail chains (mainly in America though as their use is more expensive than DAB or HD Radios in high density areas). They also provide Radio to American and Canadian airlines. Not as a set rule but in most of the cases – satellite radio is superior to all FM and AM radios as they are using AAC+ codec which is favorable to analogue signals. There are 2 main providers of satellite radio – 1worldspace and Sirius XM Radio (Until recently there were 2 large Satellite radio providers in America – Sirius and XM. They merged in 29th of July 2008 and started sharing all their channels on the 29th of November as a new Sirius XM Radio).

1 WORLDSPACE

1Worldspace was founded by Noah. A. Samara in 1990 with a mission to provide satellite radio to the emerging markets of Asia and Africa. They use 2 satellites AfriStar 1 and AsiaStar. AfriStar was put to orbit in 1998 and covers Africa, Middle East, Mediterranean countries and some of Europe. AsiaStar was launched in 2000 and serves India, China, southern Russia and Southeast Asia. They also have another satellite, AmeriStar ready but not yet launched, which will cover South America and parts of Mexico (they are not planning to move to the American market as they’ve invested in Sirius XM and have a contract to share any technological development). Satellites are in fixed positions and cover around 14 million km2 (Please see the graph below).

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On the ground they are supported by 3 components ROC (Regional Operations Centre), TCR (Telemetry, Command and ranging) and CSM (Communication System Monitoring) which are monitored 24/7. Because reception might be difficult in urban areas – they’ve been licensed to build terrestrial repeating transmitters in Italy, Germany and Switzerland. 1Worldspace will be using ESDR (ETSI Satellite Digital Radio – where satellite transmits audio, mobile TV, info and graphics directly to mobile and handheld devices). Their receivers use StarMan chipsets to receive the signals. According to 1worldspace they have a potential of about 4.6 billion listeners.

Sirius XM Radio

Sirius XM Radio Inc. is the company that came from the merging of XM Radio and Sirius in July 2008. Sirius was officially launched in 1 of July 2002 as pay-for-service radio. The original name was Satellite CD Radio, Inc. which was changed to Sirius in November 18, 1999. XM was started in 1992 and dedicated to developing satellite-based digital radio service and called American Mobile Radio Corporation. They changed their name to XM Satellite Radio holdings, Inc in 1997. Official service was launched in September 25, 2001. After the merged they now have over 19 million subscribers.At the same time  they still broadcast to different audiences as neither of their receivers is capable of receiving rival material. XM broadcasts 170 channels using aac+ codec, Sirius 130 channels using Pac. They currently have 7 satellites in orbit: 4 of XM’s (They are Boeing HS 702 Satellites called Rock (launched 2001), Roll (2001), Rhythm (2005) and Blues (2006). Their GEO (Geostationary Earth Orbit) is stationary at 35764 km above Earth. Rhythm and Blues are used now and Rock and Roll serve as backups) and 3 of Sirius’s (Sirius originally used three SS/L-1300 satellites to form an inclined elliptical path that would spend about 16 hours over US, meaning there is always at least on satellite over US. They were installed in 2000. They bought a 4th satellite- GEO for its superior quality in 2006. It is currently in construction).

As you can see from the graph – they continue to get more and more subscribers. Partly because they have struck deals with major car manufacturers (General Motors and Honda) and partnered with car audio companies (Pioneer, Alpine, Sony, Motorola etc.).

www.orbitcast.com

Multichannel possibilities

Some of their audio content is pre-processed using Neural Audio processors that are optimised for the AAC+ codec. The system is called XM HD Surround Sound. This allows them to broadcast multichannel audio, which saw XM Radio launch 2 round the clock 5.1 Surround audio channels in 2006 (they now have 6 surround radios). This is a matrix system. Please see the picture below.

www.neuralaudio.com

The first wave of home audio systems capable of playing XM HD Surround Sound are now arriving at retailers. XM HD Surround Sound manufacturing partners include Yamaha, Pioneer, Onkyo, and Denon. These systems will carry the XM-Ready and Neural Surround logos. Home audio systems with XM HD Surround will deliver the full surround experience with six discrete channels of digital full fidelity. A good thing also is that since being backwardly compatible with regular radios these broadcasts can also be heard on any existing mono, stereo, or matrix type receiver. Obviously missing out all the surround information so I dont really know why you’d want to do that…

All taken to account – satellite radio is here to stay. Like cable TV for regular TV it will complement the terrestrial radios. On the positive side: most of the them allow you to pause, rewind and even record the show or music + they provide you with information about the song, band or sports results. Even more – they don’t have commercials screaming at you every 15 minutes. The only downside I can find to this system is that it’s a subscription service, while almost all other radio types are free.