As you've probably gleaned from TV commercials and the offers flooding your mailbox, the cable and satellite companies are pushing services that promise a broad selection of programming plus enhanced picture and sound quality. So even if you're not in the market for a new TV set, you may be mulling over a new service provider.

There are three ways to get TV signals into your home: an off-air antenna, cable, and satellite. Most households currently subscribe to cable, but satellite continues to gain ground. Antennas, the least common choice, are often used to supplement satellite or cable.

People in an "unserved" household--those living in rural areas where an acceptable TV signal cannot be received via a common rooftop antenna--can pick up East or West Coast feeds of major networks from a satellite provider. According to the FCC, you should be able to confirm your status through the satellite provider from which you're getting your setup. Note that satellite does not carry the community and school channels that cable must supply.

For much of the country, cable remains the only way to receive all local programming, including broadcast-network channels such as ABC, CBS, NBC, Fox, UPN, WB, and PBS.

What's available

An antenna offers limited programming, with none of the premium channels you can get via cable or satellite. Don't expect top-quality reception unless you have close, unobstructed access to the TV stations' transmitters.

Analog cable usually has better, and more consistent, quality than you'll get with an antenna, but quality still varies by station. Analog cable also has a wide variety of programming, including premium channels such as HBO and Showtime.

Digital cable offers improved picture and sound quality, along with up to 200 or so channels, with extensive movie and sports programming (much of it not available on analog cable at any price) and commercial-free music. To receive HD programming, you need a special HD-capable cable box and an HD-ready TV. Check with your cable company to see how much HD content it currently provides; in some areas, the cable provider doesn't yet offer much.

Spiraling costs are a chronic complaint from cable subscribers. Unfortunately, most viewers can't switch to another cable provider. In most areas, there's only one company offering service. Where there is competition between cable companies, prices tend to be lower.

With satellite TV you have a choice of providers: DirecTV and EchoStar's Dish Network both operate nationwide. Like digital cable, satellite gives you picture and sound quality that's comparable to DVD plus up to 200 channels of programming, including commercial-free CD-quality music channels. Movie and sports programming is strong, with a wide range of choices. Local channels, excluding community programming, are available at extra cost in many but not all areas.

Satellite TV requires a dish that's mounted outdoors and a receiver that sits near your TV. The equipment will work with only one provider's signals. To get HD broadcasts, you need a second or larger dish and an HD-capable satellite receiver. HD programming is largely limited to premium channels like HBO and Showtime. The major networks' HD programming is generally not available via satellite, but you may be able to get it using a roof antenna.

Important features

A cable box is necessary to view premium (scrambled) channels on analog cable. Some cable companies require that you rent a box even for basic packages; otherwise, you can plug the cable directly into most TVs. When a box is required, you need one for each TV.

For digital cable, you have to rent a digital cable box for each TV on which you want to view the digital offerings (you can have analog cable on other sets). Digital cable is the only way to get video-on-demand, which lets you watch programs whenever you like.

The number and type of audio and video output jacks on the cable box or receiver make a difference in the quality of your picture and in what equipment you can connect. The lowest-quality connection is radio-frequency (RF), which is the typical antenna-type connector. A composite-video output is better; better still are S-video outputs, provided your TV is appropriately equipped to accept these connections, which can take advantage of the higher visual resolution of the digital video source. HD-capable equipment will also have component-video output, which provides the best-quality connection of all. Satellite receivers or digital-cable boxes with Dolby Digital audio capability have optical or coaxial output for a direct connection to a Dolby Digital audio receiver.

Some remote controls accompanying the receiver are infrared, like TV remotes, requiring a line of sight to the box. Others use a radio-frequency signal, which can pass through walls, allowing the receiver to be placed in an unobtrusive, central location and controlled from anywhere in the house.

Remotes typically include a program-description button, which activates an onscreen program-description banner. The program guide helps you sort through the hundreds of channels. Program guide with picture lets you continue to watch one program while you scan the onscreen channel guide for another. Some receivers have a keyword search: You can enter the full or partial name of a program or performer and search automatically through the listings.

How to choose

Performance differences. If you are a cable-TV subscriber, the odds are your cable company is trying to sell you on digital cable. A supplement to your regular (analog) service, it provides more channels and promises a superior picture and sound. Assuming you can receive digital cable (at this point, almost all cable customers can), upgrading your service is as simple as placing a phone call and arranging for installation of a new cable box. Satellite service requires an unobstructed view of the satellite; you then choose between DirectTV and EchoStar's Dish Network.

Recommendations. Off-air reception via an antenna is the only way to get essentially free TV service, even for HD broadcasts.

If you're an occasional TV watcher who's generally satisfied with the channel selection you've had for years, analog cable, with its relatively low monthly bill, may be all you need.

If you now have analog cable but want more channels or better picture and sound quality, you can upgrade to digital cable (at a higher price) or switch to satellite-(higher-priced than analog cable for all but basic satellite packages). Both offer much more choice, especially for movies, sports, and foreign-language programs. Find out the program offerings in your area, including whether digital cable is available (or when it will be) and if local channels are available on satellite. Community channels are available only on cable, though.