Direct broadcast satellite (DBS) operators use satellites to transmit video programming to subscribers, who must buy or rent a small parabolic dish antenna and pay a subscription fee to receive the programming service. DBS meets consumer demand for entertainment programming, Internet connectivity, and multimedia applications.
DBS offers more programming choices for consumers and a platform for the development of new services, including video on demand, interactive TV, Internet messaging services, and personalized on-demand stock quotes. Much of the growing popularity of DBS is attributable to the programming choices available to consumers as well as the picture quality provided by digital technology.
And like cable television systems, DBS offers programming in the high-definition television (HDTV) format. One of the most popular DBS services is DirecTV, a unit of Hughes Electronics, which markets the service worldwide. First introduced in the United States in 1994, DirecTV offers over 225 channels and has over 10 million customers.
The satellite service requires the user to have an 18-inch dish, a digital set-top decoder box, and a remote control. The system features an on-screen guide that lets users scan and select programming choices using the remote. Customers also can use the remote control to instantly order pay-per-view movies, as well as set parental controls and spending limits.
The DirecTV installation includes an access card, which provides security and encryption information and allows customers to control the use of the system. The access card also enables DirecTV to capture billing information. Astandard telephone connection is also used to download billing information from the decoder box to the DirecTV billing center. This telephone line link enables DirecTV subscribers to order pay-per-view transmission as desired.
DirecTV allows users to integrate local broadcast channels with satellite-based transmissions. In markets where broadcast or cable systems are in place, users can maintain a basic cable subscription or connect a broadcast antenna to the DirecTV digital receiver to receive local and network broadcasts. Aswitch built into the remote control enables consumers to instantly switch between DirecTV and local stations.
HDTV programming from DirecTV is delivered from its 119° west longitude orbital slot location. To receive HDTV programming, consumers must have an HDTV set with a built-in DirecTV receiver or a DirecTV-enabled HDTV settop converter box. Asmall elliptical satellite dish is needed to receive HDTV programming from the 119° orbital slot location, as well as core DirecTV programming from the 101° orbital location.
Internet access is provided via two services. The older service is DirecPC, a product that uses DirecTV technology in conjunction with a PC to deliver high-bandwidth, satellitebased access to the Internet. The DirecPC package includes a satellite dish and an expansion card designed for a PC’s input-output (I/O) bus. This receiver card transmits data from the Internet to the computer at 400 kbps, a rate 14 times faster than that of a 28.8-kbps modem connection.
Users connect to the Internet service provider (ISP) through a modem connection, but the ISP is responsible for routing data through the satellite uplink and transmitting the data to the receiver card and into the computer (Figure D-2). The service also provides users with the option to “narrowcast” software from the head end of a network to branch users during off-peak hours.
Additionally, DirecPC transmits television broadcasts from major networks, such as CNN and ESPN, to the user’s computer system. The company’s newer service, DirecWAY, offers a two-way broadband connection that offers 400 kbps on the downlink and about 150 kbps on the uplink, which eliminates the need for a modem and separate phone line.
A new dish antenna provides access to the Internet and cable programming. Abusiness- class DirecWAY service is also available. Multiple-seat account options (2 seats is the entry-level service; 5-, 10-, and 20-seat options are available), LAN software routing, and firewall security are offered as part of the business class service.
DBS operates in the Ku band, the group of frequencies from 12 to 18 GHz. TV shows and movies are stored on tape or in digital form at a video server, while live events are broadcast directly to a satellite (Figure D-3). Stored programs are sent to the uplink (ground-to-satellite) center manually via tape or electronically from the video server over fiberoptic cable. Live events also pass through the uplink center.
There, all programs—whether live or stored—are digitized (or redigitized) and compressed before they are uplinked to the satellites. All DBS systems use the MPEG-2 compression scheme because it supports a wide range of compression ratios and data rates. It is capable of delivering a clean, high-resolution video signal and CD-quality sound.
The satellites broadcast over 200 channels simultaneously via the downlink. The home satellite dish picks up all the channels and sends them via a cable to a set-top decoder. The set-top decoder tunes one channel, decodes the video, and sends an analog signal to the TV.
More than 1 million U.S. residents have installed small TV satellite dishes to receive programming via satellite services. At this writing, there are four direct broadcast satellite systems in operation: PrimeStar, EchoStar, Digital Satellite Service (DSS), and AlphStar. DirectTV uses DSS and PrimeStar. Ordering PrimeStar service is similar to ordering cable: After the order is placed, a technician installs the dish and activates programming.
DSS, EchoStar, and AlphaStar services also give users the option of installing the dish themselves. The dish must be placed so that it can capture a clean signal from the nearest satellite—usually on the roof, facing south. To activate service, the user calls the programming provider to obtain a unique satellite dish address.
The key component of the DBS system is the dish antenna, which comes in various sizes. Dish size depends on the strength of the satellite signal; the stronger the signal, the smaller the dish can be. Users select the dish according to their geographic proximity to the satellite source. This also explains why it is necessary to install the dish so that it points in a specific direction.
If the satellite sits on the southern horizon, the dish must be pointed south. The user also needs a receiver-decoder unit, which tunes in one channel from the multitude of channels it receives from the dish. The decoder then decompresses and decodes the video signal in real time so that the programs can be watched on the television set. These set-top units also may include a phone-line connection for pay-per-view ordering and Internet access.
Taping DBS programs requires the settop unit to be tuned to the correct channel. To make recording easier, some receiver-decoders include an event scheduler and an on-screen programming guide.
As with most audio-video components, DBS units come with a remote control. Some manufacturers offer a universal remote that also can be used to operate the TV and VCR. The accessories available for DBS systems deal with secondary and tertiary installations.
Users can buy additional receiver-decoder units or multiroom distribution kits, which use either cable or radio frequencies to transmit the signals from the original set-top unit to other rooms. Some kits enable the VCR to be plugged into the distributor.
Each of the four DBS systems currently available provides similar core services. The differences lie mainly in the availability of premium movie channels, audio channels, pay-perview events, Internet services, and custom features. With more than 200 channels to choose from, the onscreen programming guide can become an important factor when selecting a service.
Most guides enable users to sort the available programming based on content area—such as sports, movies, comedies—or list favorite channels at the top of the menu. Depending on the equipment selected, users can even store the favorite-channel profiles of multiple family members. Parental lockout enables adults to block specific channels or programming with a specific content rating or to set a maximum pay-per-view spending limit.
Channel-blocking options are protected by passwords; with multiprofile units, parents can customize the system for each child. The addition of digital television recording systems such as TiVo allows viewers to easily find and schedule their favorite television shows automatically and digitally record or store up to 35 hours of video content without the use of videotape.
Such systems provide the ability to pause, rewind, replay, and slow motion live shows. An advanced programming guide allows viewers to check program listings up to 14 days in advance.
Despite increases in the number of subscribers to DBS systems in recent years, CATV systems remain the dominant supplier in what is called the “multichannel video program distribution” (MVPD) market. The FCC has regulatory authority over DBS and is charged with implementing the Satellite Home Viewer Improvement Act of 1999 (SHVIA).
This law provides that after December 31, 2001, each satellite carrier providing television broadcast signals to subscribers within the local market of a television broadcast station of a primary transmission made by that station shall carry on request the signals of all television broadcast stations located within that local market.
Until January 1, 2002, satellite carriers were granted a royalty-free copyright license to retransmit broadcast signals on a station-by-station basis, subject to obtaining a broadcaster’s retransmission consent. This transition period was intended to provide the satellite industry with time to begin providing local signals into local markets—in effect, providing local-into-local satellite service.
While DBS competes well against cable television in terms of television programming, it may not be able to compete with cable on the data front. In contrast with the finite bandwidth available to wireless and satellite systems, the terrestrial broadband pipe technologies available to cable systems offer bandwidth that is virtually limitless for almost all current practical purposes.
Duplication of this pipe requires an investment of tens of billions of dollars and therefore would be impractical. Realizing this, DBS services limit downlink throughput per subscriber at about 400 kbps and reserve the right to limit bandwidth-hogging activities, such as audio and video streaming, and automatic file exchange applications. These restrictions are justified as being necessary to preserve an adequate level of service for all subscribers.