Get ready for new TV era.

Since the first days of television, the method of beaming pictures into our living rooms hasn’t changed much. But on Feb. 17, 2009, television stations across the country will hit the off button on this time-tested technology and switch to new transmitters, sending computerized digital signals through the air. When the change comes, the estimated 30 million televisions that use traditional antennas will go to snow without a digital converter box. The cable industry is spending $200 million to educate customers, and Congress has set aside $1.5 billion to help subsidize the purchase of converter boxes.

Still, half of American viewers don’t know the storm is coming, according to a poll conducted last month by the Cable & Telecommunications Association for Marketing. For the 1 in 5 American households that still use rabbit ears or antennas on the roof, “the day of reckoning is coming,” said Barry Umansky, a communications professor at Ball State University in Muncie, Ind.

Not enough spectrum for all those signalsThe switch to all-digital television, and a similar switch in the wireless communications industry, is partly a repercussion of the terrorist attacks of Sept. 11, 2001, when police and fire communications channels were clogged by too much traffic. The Federal Communications Commission first ordered the eventual transition in 1996, but Congress didn’t set a deadline until the the 9/11 Commission reported that first-responder systems needed a major upgrade.

The problem, said Umansky, a longtime broadcast industry lawyer, is that “America’s seemingly wide-open skies are chock full of radio signals, and there just aren’t enough frequencies for all the people who need to use them.” By taking back the analog frequencies, the government will “allow the nation’s airwaves to be used by firefighters, police and other first responders to help the nation when there might be a natural or manmade disaster,” said Todd Sedmak, communications director of the National Telecommunications and Information Administration.