Tim Bedison / Fort Worth Star-Telegram

HACKENSACK, N.J. Why pay for high-definition television service each month?

Why not receive an HD signal over the air with (gasp) a TV antenna?

There is one catch you need to have the right equipment. But once you have it, you can receive high-definition TV over the air at no cost. It's a thrifty option for both consumers and small businesses.

OK. There's more than one catch. You can't get a vast number of cable channels, so if you're hooked on HBO or the History Channel, you won't be happy going this route. If you don't watch much TV, but would enjoy a crisp high-definition picture without a monthly cable bill, then read on.

Most TVs sold today have a built-in tuner, called an ATSC tuner, that's able to receive both high-definition and "regular" digital signals over the airwaves. If you have an older HD set without a tuner (sometimes called HD-ready TV), you need to purchase a decent external tuner for about $180 (Samsung's model DTB-H260F gets high marks from reviewers) to receive HDTV over the air.

Before you begin, check the Consumer Electronics Association Web site http://www.antennaweb.org. Besides a trove of helpful information, you can enter your street address and it will estimate the number of over-the-air channels you are likely to receive.

You can go retro here and install a large outdoor antenna, or you can choose a small indoor antenna, which is a tempting option. Although some electronics experts warn that you won't get quite as good reception.

But the indoor antennas have many fans among TV geeks. They have advanced far beyond rabbit ears, although even rabbit ears can pull in an HD signal. In fact, many experts pointed out that companies like to market antennas as "HD antennas," but they really aren't any different from any other antennas.

The CNET Web site (http://www.cnet.com) advises, "If you still have an old-school UHF/VHF antenna, give it a try before coughing up the extra cash for a dedicated HD antenna."

The smaller indoor units range from $10 up, but most everyone agrees that $50 will get you a state-of-the-art indoor antenna. (Radio Shack's model 15-1880 is recommended by people who have tested numerous models.)

The prices on outdoor models are $30 and up. And prices of those large flat-panel TVs keep dropping. You can purchase a 27-inch HDTV with a built-in tuner for $500.