Thursday, June 10, 2010

Satellite Car Audio

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, such as HD Radio, rather than satellite radio.

Business applications

Satellite radio, particularly in the United States, has become a major provider of background music to businesses such as hotels, retail chains, and restaurants. Compared to old-line competitors such as Muzak, satellite radio's significantly lower price, commercial-free channel variety, and more reliable technology make it a very attractive option. Both North American satellite radio providers offer business subscriptions, though given the merger of XM Satellite Radio with Sirius, the future of XM for Business is uncertain. Sirius's commercial services are provided nationally by third-party partner Applied Media Technologies Corporation. Satellite radio has a large following within the truck driving community as well. The advantage of driving from coast to coast without losing signal is an obvious advantage. Both providers offer programming aimed at trucking professionals.

System design

Satellite radio uses the 2.3 GHz S band in North America and generally shares the 1.4 GHz L band with local Digital Audio Broadcasting (DAB) stations elsewhere. It is a type of direct broadcast satellite and is strong enough that it requires no satellite dish to receive. Curvature of the earth limits the reach of the signal, but due to the high orbit of the satellites, two or three are usually sufficient to provide coverage for an entire continent.

Local repeaters similar to broadcast translator boosters enable signals to be available even if the view of the satellite is blocked, for example, by skyscrapers in a large town. Major tunnels can also have repeaters. This method also allows local programming to be transmitted such as traffic and weather in most major metropolitan areas, as of March 2004.

Each receiver has an Electronic Serial Number (ESN) Radio ID to identify it. When a unit is activated with a subscription, an authorization code is sent in the digital stream telling the receiver to allow access to the blocked channels. Most services have at least one "free to air" or "in the clear" (ITC) channel as a test. For example, Sirius uses channel 184, Sirius Weather & Emergency.

Most (if not all) of the systems in use now are proprietary, using different codecs for audio data compression, different modulation techniques, and/or different methods for encryption and conditional access.

Like other radio services, satellite radio also transmits program-associated data (PAD or metadata), with the artist and title of each song or program and possibly the name of the channel.

United States

In the United States, two companies operate satellite radio services: XM Satellite Radio and Sirius Satellite Radio, though these companies are merging. A monthly fee is charged for both services (as of 2005, Sirius also offers a one-time fee of nearly $500 valid for the lifetime of the equipment). Some XM music channels have commercials, while Sirius is commercial-free. Both services have commercial-free music stations, as well as talk and news stations, some of which include commercials. XM uses fixed-location geostationary satellites in two positions, and Sirius uses three geosynchronous satellites in highly elliptical orbits passing over North and South America, to transmit the digital streams. The net difference is that the Sirius signal comes from a higher elevation angle in the northern part of the U.S. and even more so in Canada. (This higher angle makes Sirius' signal less likely to drop out on cities, but more likely to drop out in parking garages, gas stations, tunnels, and other covered spaces.)

Both services are available mainly via portable receivers in automobiles, but both have many accessories so one can listen at home through a home stereo, with a portable boombox, or online through a personal computer. Both services now have some form of receiver that is completely portable.

Satellite radio's chief asset is the fact that it is not localized: drivers can receive the same programming anywhere in the footprint of the service. A stop at any truck stop will demonstrate the popularity of XM among long-haul drivers. In addition, both XM and Sirius carry programming that is simply not feasible on commercial radio stations. Specialty stations cover things such as family talk, radio drama, classical music, and live events.

The footprint of both Sirius and XM is only the United States (including Alaska), Canada, and the upper third of Mexico; it does not cover Hawaii as satellite TV does.

Success so far

As of Feb 28,2008 XM claims over 9 million subscribers, while Sirius claimed 7.6 million as of October 30, 2007. One critical factor for the success of satellite radio is the deployment of in-car receivers. Both Sirius and XM have attempted to convince automakers to equip vehicles with their receiver. As of 2007, the following manufacturers offer satellite radio as original Sirius has an exclusive contract for VW and Audi vehicles from 2007 through 2012[citation needed]. Those brands previously offered both services. GM, Honda and Suzuki are all major investors in XM; Sirius is not offered as options in their vehicles.[1] Bentley and Rolls-Royce come not only with receivers and lifetime subscriptions for Sirius service. XM is featured in select Harley-Davidson motorcycle models, while Sirius can be heard in several brands of recreational vehicles and boats.

One of the challenges for satellite radio has been to move away from cars and into the homes of consumers.[citation needed] Several portable satellite radio receivers have been made for this purpose. XM satellite radio has developed the XM2go line of "Walkman-like" portable receivers, such as the Delphi MyFi, the Pioneer AirWare and Giant International's Tao. Polk Audio makes a component-style home XM Reference Tuner[2] and a tabletop entertainment system, the I-Sonic[3], with XM capability. Sirius has developed the Kenwood Portable Satellite Radio Tuner, Sirius S50, Here2Anywhere and the Sirius Stiletto 100.[4] The Pioneer Inno and Samsung Helix for XM were among the first portable receivers to offer the ability of recording live content for playback later. Thus allowing for satellite radio to compete more fully with MP3 players.

While key agreements with automobile manufacturers are still being made, both companies have made the leap away from satellite radio only in the car and into the homes of consumers. One bump in the road to becoming more widely used in the home was both Sirius and XM running into legal issues in early 2006 with the FCC about their internal FM Transmitters. This required Sirius and XM to pull several of their models off the shelf and fix the problem. The FCC was claiming that the emissions of the internal FM Transmitters were too powerful and needed to be lowered. With these changes any customer buying a new satellite radio receiver doesn't achieve nearly the broadcast distance as the old models. Since this is a key point in the ability to use a satellite radio in the home (i.e. by taking the signal received and then broadcasting it to multiple points throughout the home at the same time and avoid having to bring the satellite radio with them as they move around the home) it has led many subscribers to use an external Personal Fm transmitter like the Whole House FM Transmitter, C Crane, Griffin Technology, etc. to replace the lower powered internal FM Transmitter. Since these external FM Transmitters are Part 15 compliant they can broadcast the signal further than the new internal FM Transmitters now included in the satellite radios and still be legal. These external FM transmitters may prevent a slow down in the progress already made into the home consumer market for Sirius and XM satellite radio.


On November 1, 2004, the Canadian Radio-television and Telecommunications Commission (CRTC) began hearing applications for Canada's first satellite radio operations. Three applications were filed: one by Standard Broadcasting and the CBC in partnership with Sirius, one by Canadian Satellite Radio in partnership with XM, and one at the last minute by CHUM Limited and Astral Media.

The first two would use the same systems already set up for the U.S., while CHUM's application is for a subscription radio service delivered through existing terrestrial DAB transmitters rather than directly by satellite (although satellites would be used to deliver programming to the transmitters). The CHUM service is all-Canadian; the other two applications propose to offer a mix of Canadian-produced channels and existing channels from their American partner services.

A small "gray market" already exists for Sirius and XM receivers in Canada in which a Canadian would have an American order their receiver and setup.

On June 16, 2005, the CRTC approved all three services.[5]

In its decision, the CRTC required the following conditions from the satellite radio licensees:

A minimum of eight channels must be produced in Canada, and for each Canadian channel, nine foreign channels can be broadcast.

At least 85% of the content on the Canadian-produced channels (whether musical or spoken word) must be Canadian.

At least 25% of the Canadian channels must be French-language stations.

At least 25% of the music aired on the Canadian channels must be new Canadian music.

At least 25% of the music played on the Canadian channels must be from up-and-coming Canadian artists.

These conditions were an extension of the existing Canadian content rules applicable to all broadcasters in Canada. The applicants had until 13 November

2005, to notify the CRTC of their decision. Both companies managed to negotiate the standards a little to their favor, and in return, they would instead play 50% French content as opposed to 25%. Also, XM Canada succeeded in getting an extra five channels of National Hockey League Play-by-Play onto their platform, without an additional channel creation, by agreeing to cover every Canadian team's game during the season.

CHUM appealed the decision, claiming they would not survive if Sirius and XM [] both were allowed in the Canadian market, and that the licence conditions regarding Canadian content imposed on Canadian Satellite Radio and Sirius Canada were too lax. Canadian Satellite Radio and Sirius Canada countered that CHUM was simply trying to create a monopoly in the Canadian market.

In late August 2005, Heritage Minister Liza Frulla asked the Federal Cabinet to review the CRTC decision and possibly send it back to the CRTC for further review. Lobbyists complained that the CRTC decision did not require enough Canadian content from the broadcasters. The broadcasters responded by promising to add additional Canadian and French content.

After vigorous lobbying from both sides, the Federal Cabinet officially accepted the CRTC decision on September 10, 2005.


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