High-definition television watchers in the Roanoke area know there's a gaping hole in local coverage: HD programming from WSLS, the local NBC affiliate, isn't available over cable TV.

It's not as if you can't get NBC in HD. WSLS has been broadcasting its HDTV signal since April 2002 from a transmitter on Poor Mountain, but Roanoke-area viewers without the right antenna and converter box can't get it.

That's because Media General, which owns WSLS, has not reached an agreement with either Cox Communications or Adelphia Communications to have them carry the station's HD signal. The cable companies do carry WSLS' standard-definition programming.

In most cases, cable companies and TV stations sign what's known as a retransmission agreement that benefits everyone: The cable companies get more programming for their customers, and the networks get more exposure for their programs - and, of course, their advertising.

But HDTV is different, and in the case of Media General and local cable companies, the differences have led Cox corporate spokeswoman Amy Kohn to say, simply, "Our negotiations are really at an impasse." (Adelphia spokeswoman Erica Stull said her company does not discuss ongoing negotiations.)

The digital signal that makes HDTV possible carries more information than a traditional, analog signal. That additional bandwidth opens more possibilities for television stations - a second or even third "channel" in the same amount of space.

But cable companies' "pipes" are only so large, and they want to offer content from as many stations as possible. To that end, they compress an HD signal to fit more channels into your living room.

Cable companies also limit the amount of bandwidth they give each station. As Kohn said, "There was some language in our proposed agreement that would call for things they [WSLS] can and can't do with their digital spectrum."

And that, said WSLS station manager Kathy Mohn, won't fly.

"We've taken the position that if a cable operator wants to carry our digital signal, it should at least agree to carry it in the same form that we transmit it, with nothing added and nothing deleted," she said. "We don't want an intermediary dictating what we can and cannot carry, period."

Kohn said that Cox's offer is no different from what it provides the other stations in the market, all of which Cox carries.

"It would prevent them [WSLS] from deploying a pay-per-view service or an on-demand service, or reselling the spectrum to another provider," she explained. "And that's really standard in the industry."

Mohn reiterated that any restriction is unacceptable. "We have phenomenal plans" for HDTV, she said. The station might use the additional bandwidth "for new services, such as weather and traffic information, extended news, repeated programs or extended coverage of public events."

But it should be the station's choice, not the cable company's. "We just do not want to have to have our plans approved or rejected by any carrier," she said.

The issue for Cox is exactly what that added content might be.

Michael Pedelty, local spokesman for Cox Communications, said that what WSLS wants is "outside the bounds of what we think is reasonable to carry."

But Mohn believes that Cox simply wants to avoid conflicts with its other content providers. "My thinking is that they want to protect the channels that they have - that they're paying for," she said. "I'm sure if we devised a way to do a home shopping network they would find that in conflict."

Another roadblock is money. Normally retransmission agreements don't involve any, except in the form of "media buys" where the cable company runs commercials on the station.

Both sides alluded to the issue, but none was willing to give specifics.

Pedelty came closest: "It's safe to say that they want money or some other consideration that we're just not able to give."

WSLS' Mohn pointed out that the cable operators get a terrific deal on local content.

"Cable operators pay for most of the channels that they carry," she said. "They pay nothing, however, for the local broadcast channels."

She would not specify what kind of money Media General was looking for, if any, although she said, "It certainly would be nice to get some kind of compensation." After all, she points out, as the manager of a television station, "I'm the one that invested $3 million in high definition."

For Cox's part, Kohn doesn't think the cable company should pay for something that's given away free. "We have this issue at times with broadcasters wanting us to pay for their free over-the-air signal," she said.

Although, she added, "That doesn't mean we're not willing to compensate them in some way."

Will cable TV viewers here without an HD antenna ever be able to get "ER" in high definition? The roadblocks are a-plenty.

"Compensation is an issue," Mohn said. "Content is an issue. Bandwidth is an issue. Freedom to build our high-definition programs without having anyone dictate is an issue."

Still, Pedelty is an optimist. "We'd absolutely love to have them on. We're not saying it's our way or the highway - we're open to discussion."