Buying an antenna for a high-definition television seems as out of place as using a rotary phone to make a call.

But some consumers are spending thousands of dollars on LCD or plasma TVs and hooking them up to $50 antennas that don't look much different from what grandpa had on top of his black-and-white picture tube.

They're not doing it for the nostalgia.

Local TV channels, broadcast in HD over-the-air, offer superior picture quality over the often-compressed signals sent by cable and satellite TV companies. You may also get "extra" channels that cable and satellite systems don't carry.

For instance, KXII-TV currently offers three digital channels: Channel 12.1 (KXII/CBS) is broadcast in HDTV; Channel 12.2 is My Texoma; Channel 12.3 is Fox Texoma, and it provides Fox network programming in HD as well.

And the best part? Over-the-air HD is free.

"Eighty-year-old technology is being redesigned and rejiggered to deliver the best picture quality," said Richard Schneider, president of Antennas Direct. "It's an interesting irony."

A few years ago, Schneider started an assembly line in his garage and sold antennas out of the trunk of his car. Now his Eureka, Mo.-based company has seven employees and did $1.4 million in sales last year. He expects revenue to double in 2007.

"People thought I was nuts. They were laughing at me when I told them I was starting an antenna company," Schneider said.

Before cable and satellite existed, people relied on antennas to receive analog signals from local TV stations' broadcasting towers. Stations still send out analog signals, but most now transmit HD digital signals as well. (Congress has ordered broadcasters to shut off old-style analog TV broadcasts by Feb. 17, 2009.)

Consumers who can get a digital signal from an antenna will get an excellent picture, said Steve Wilson, principal analyst for consumer electronics at ABI Research.

One major difference with a digital over-the-air signal is it doesn't get snowy and fuzzy like the old analog signal. Instead, the picture will turn into tiny blocks and go black.

"You either get it or you don't," said Dale Cripps, founder and co-publisher of HDTV Magazine. "Some people can receive it with rabbit ears, it depends where you are."

Schneider recommends indoor antennas only for customers within 25 miles
of a station's broadcast tower. An outdoor antenna will grab a signal from up to 70 miles away as long as no mountains are in the way, he said.

These digital transmissions are not, however, being sent out on familiar channel numbers. KXII-TV (Channel 12 in the analog world) is broadcast on Channel 20 digitally. But information sent along with the signal tells your receiver that it is getting "12.1," "12.2" and "12.3."

The Consumer Electronics Association maintains the AntennaWeb site that tells how far an address is from towers and recommends what type of antenna to use.

"When you're using an antenna to get an HD signal you will be able to receive true broadcast-quality HD," said Megan Pollock, spokeswoman for the group. "Some of the cable and satellite companies may choose to compress the HD signal."

Compression involves removing some data from the digital signal. This is done so that the providers will have enough room to send hundreds of other channels through the same cable line or satellite transmission.

The difference in picture quality is a matter of opinion, said Robert Mercer, spokesman for satellite provider DirecTV Inc.

"We believe the DirecTV HD signal is superior to any source, whether it's over-the-air or from your friendly neighborhood cable company," Mercer said.

Others disagree.

Self-described TV fanatic Kevin Holtz, of suburban Cleveland, chose an antenna because he didn't want to pay his satellite provider extra for local broadcast channels.

Holtz, 30, can't get the signal from one local network affiliate or a public broadcasting station but said the rest of the stations come in clearer than they would through satellite. He uses a $60 antenna for a 40-inch Sony LCD, which retails for about $3,000.

"Over-the-air everything is perfect," Holtz said.

Another downside to using just an antenna is that only local channels are available, meaning no ESPN, TNT, CNN or Discovery Channel. Some consumers partner an antenna with cable or satellite service.

Many people aren't aware that they can get HD over the airwaves, Wilson said. He estimates there are 10 million households with HDTVs and that fewer than 2 million of them use antennas. Including homes with analog sets, 15 million of the 110 million households in the United States use antennas.

HD antenna prices range from $20 to $150 for indoor and outdoor versions. The many models of available indoor antennas look more like a fleet of spaceships than the rabbit ears of old. Brand names include Terk, RadioShack, Philips, Audiovox, Jensen and Magnavox.

Those really interested in saving a buck and who have a little MacGyver in them could make their own antenna. Steve Mezick of Portland, Ore., created one out of cardboard and tinfoil.

"I decided to build it because the design looked exceedingly simple. I scrounged up stuff around the house and put one together," said Mezick, a bowling alley mechanic who repairs pin spotters.

The 30-year-old has since upgraded his original design using a wire baking sheet, clothes hanger and wood. He mounted it to the side of his house and gets all of his local stations.

"It works brilliantly," he said.

But you don't necessarily need a space-age design to receive the new digital channels. Any antenna capable of receiving analog VHF and UHF channels can be used to hook up to an HDTV receiver. So if you have an unused antenna on the roof or in an attic, it may be all you need to open up a new world of television.

The Associated Press contributed to this report.