Fourth quarter, six second left, Steelers and Ravens are tied 17-17. Jeff Reed lines up for the winning field goal, boots it ... it's long enough ... it's high enough ... and your TV loses its signal.

It's every Steelers fan's worst nightmare, and it's a concern shared by America's television broadcasters, wary of what might happen after televisions abandon the analog spectrum for a digital feed on Feb. 17, 2009.

But is it a realistic concern?

Maybe.

Last year, a new generation of wireless device being tested by the Federal Communications Commission caused nearby television sets to go on the blink. Subsequent tests of similar devices have yielded unexpected power failures.

The devices are meant to search for the "white space" between the digital signals, a buffer zone of empty bandwidth that prevents two signals from interfering with each other (kind of like radio signals do when you're between two geographic centers). Internet titans such as Google and Microsoft want to use the empty airwaves to create an ultrafast wireless Internet transmission spectrum, one that would allow transfer rates of gigabits per second, rather than megabits per second.

The catch is that the technology isn't there -- yet. Tech giants say the scanners are the future of the Internet, "Wi-Fi on steroids," bringing high speeds to rural areas still neglected by major broadband players such as Comcast or Verizon. But could the high-speed Internet of the future interfere with the television of the future?

"The only business model we have is based on our ability to deliver clear picture to our viewers," said Dennis Wharton, a vice president with the National Association of Broadcasters, which represents more than a thousand local TV stations. "Anything that threatens that model threatens our business."

Next year, all TV broadcasters -- from KDKA to WTAE to WPXI -- will be required to transmit on the digital spectrum. Because digital signals take up less airwave space than analog signals, there will be more buffer room between the signals for whoever wants to transmit there (wireless microphones, for example, already use bits of that spectrum). Google and Microsoft -- and Dell, HP, Samsung and others members of the so-called White Spaces Coalition -- hope to come up with devices that can reliably detect digital television transmissions, as well as other "incumbent" spectrum users, such as nearby wireless sound systems. If they can detect the transmissions, the devices also should be able to zero in on soft spots between the transmissions, and use that empty space to transmit cell phone and Internet data through the airwaves.

They want to access that bandwidth because there's only so much unlicensed bandwidth available, and those bands -- 2.4GHz, for instance -- are being quickly filled with other devices, such as cordless telephones.

Right now, the FCC is trying to come up with a set of guidelines by which these "white space" scanners and transmitters would abide. If it does that by the end of 2008, devices could be in the market by next year.

Edmond Thomas, partner in the law firm of Harris Wiltshire & Grannis and adviser to the White Spaces coalition, said the broadcasters' interference concerns were hugely overblown.

"The broadcasters have never supported any use of TV spectrum that didn't have a TV application," he said. "They want to reserve to themselves the spectrum for future use."

He also noted that for whatever consternation the broadcasters are expressing, the television makers themselves are on board with the technology.

Philips Electronics, for example, wants to incorporate the white space scanners into future television models. Presumably, that's so the TVs could send digital images around the house, to other devices.

Philips wants to use the technology to make sure "TV is a better experience," Mr. Thomas said. Would they do that if they thought the technology would interfere with its own products?

For a year, the broadcasters have been feuding with the tech giants over that white space usage. Broadcasters, having already invested millions in a new digital infrastructure, don't want to run the risk -- however small -- that wireless Internet and cell phone users will be interfering with their signals.

The broadcasters say Google, Microsoft and the like could buy up a chunk of bandwidth, just like conventional phone providers, such as AT&T and Verizon, did during the FCC's recent $19 billion auction of the 700-megahertz band. But such an investment essentially would force Google and Microsoft to get into the wireless service provider business when all they really want to do is build the devices.

The devices then would be used to detect and transmit via other Internet or wireless service providers, giving consumers a choice, says Eric Bangeman, technology writer and editor with Ars Technica.

And that's the whole point.

"Right now, we have a broadband duopoly -- your DSL and cable provider -- and you get to choose between the two," he said. "The idea is to make wireless broadband ubiquitous," via the unlicensed spectrum.

Mr. Bangeman said some of the ancillary concerns -- that the white-space scanners would interfere with wireless microphones, for example -- could be easily addressed. The microphones could be outfitted with beacons, and if the white space device detected a beacon on one frequency, it would scan for another open channel.