Digital television, with its sharper pictures and potential for greater interactivity, has been widely available for several years.

But some of you out there in TV Land still watch the same way people did when The Ed Sullivan Show introduced Americans to mop tops and the upper half of Elvis Presley - via an antenna that receives analog broadcast signals.

If you're still wrapping tinfoil around rabbit ears, brace yourself.

Three days after Valentine's Day in 2009, your analog-only sets will no longer work. That's the day the federal government is ending transmission of analog broadcast signals. It may sound far away, but in the next several months, you will start to see advertising and other campaigns aimed at educating consumers about the transition from analog to digital TV.

The federal government is requiring the switch because it wants to give some of the spectrum previously used to transmit analog broadcast signals to police, fire and other emergency officials so they can communicate more efficiently.

But the bigger motivation is money. The government plans to auction off an estimated $10 billion worth of spectrum previously used for analog broadcast signals.

Cable and satellite customers should not have to do anything to prepare for the change. Satellite transmissions already are digital, and about half of all cable customers get digital service. The other half receive analog service, but the National Cable and Telecommunications Association, the industry's primary trade group, has pledged that those customers continue to get TV after Feb. 17, 2009, probably by converting the digital signal to analog.

"We intend to offer analog feeds for a number of years, certainly beyond 2009, and we'll ensure that all of our customers, including those with analog TV sets, will be able to watch their favorite channels" after the transition, Comcast spokeswoman Jenni Moyer said.

(Many cable companies, including Comcast Corp., also are shifting TV channels such as HBO from analog service to digital only, which has confused some consumers. But those changes are not related to the 2009 transition, which affects only broadcast content - the kind delivered over the air, usually from your local TV station - not cable content.)

About 20 million homes do not subscribe to cable or satellite. They are thought to have 45 million TV sets that get only analog broadcast signals. Cable or satellite customers have an estimated 28 million additional analog TV sets not hooked up to their pay-TV service.

"All this tempest in a teapot is about this dying medium," said Gerald R. Faulhaber, a professor at the University of Pennsylvania's Wharton School and a former chief economist at the Federal Communications Commission.

But TV is such a big part of daily life that broadcasters, cable companies and government officials say they are pushing to make sure no set goes dark in 2009.

"It's almost an essential service in this country for news and information," said Bill Weber, WHYY TV12 vice president and chief technology officer. "It's almost like saying you can't have a telephone."

If you get television via antenna now, several choices will ensure that you can still watch after Feb. 17, 2009.

You can get a box that will convert the new digital signal to analog so that your current TV set will still work.

The federal government has set aside about $1.4 billion for $40 coupons that are expected to lower the cost of a converter boxes to less than $50. The National Telecommunications and Information Administration, a unit of the U.S. Department of Commerce, will mail the coupons to requesting homes beginning in January 2008.

The allotted funds are not expected to pay for enough converter boxes for every analog set in the country, so get yours early. For more information, see: http://go.philly.com/dtv.

You also can buy a digital television set.

Jeannine Kenney, a senior policy analyst for Consumers Union, an advocacy group, said consumers should assess their own needs before going to the store. Retailers are phasing out the sale of analog sets, because they will no longer work after the transition. But Kenney believes some people may want to buy them and then use a coupon to get a converter box, a cheaper option than buying a digital set.

If you want to buy a digital set, be aware that you do not need a high-definition set. A sales representative may try to convince you otherwise, but you need high-def only if you crave crystal-clear pictures on a big screen. Standard digital, which still offers better pictures than analog, will do for everyone else.

A third option is to sign up for cable or satellite service.

Most area broadcasters have been sending out digital signals for several years. Jim Barger, director of operations at NBC10, expressed confidence that the transition will go smoothly.

"I think it will be a lot less painful than people think it's going to be," he said. "Most people are getting their signals through cable. It's the second or third TV in their home that may work with rabbit ears."

Contact staff writer Miriam Hill at 215-854-5520 or hillmb@phillynews.com.