Before Oprah Winfrey jetted off this month to Washington for the Kennedy Center Honors, then to Sydney for overseas tapings of her talk show, she had a simple request for the security staff at her house near Los Angeles:

"Can you all make sure that I have the capabilities to get my own channel on my own TV?"

It would be a tad embarrassing, she teased, if she had to dash to a neighbor’s house to see the start of OWN, her new cable channel.

Indeed.

After all, Winfrey is about to make history by ending her blockbuster, one-hour talk fest, "The Oprah Winfrey Show," and starting OWN, short for the Oprah Winfrey Network, that will speak for her 24 hours a day. OWN makes its debut on New Year’s Day, and its success hinges on fans being able to track down Winfrey on the upper reaches of the cable dial. On the DirecTV setup in Winfrey’s own home, her network will be on Channel 279, a big leap from Channel 7, where the current show is shown in New York, Los Angeles, Chicago and other major cities.

Winfrey’s move from broadcast to cable is a transformative moment for the television business, marking the first time a talk-show host has taken over an entire channel. The stakes couldn’t be higher for Winfrey and the coterie of television veterans that has assembled around her. For someone who has enjoyed outsize victories in almost every venture she has pursued, OWN will be the ultimate test of her power.

"I’m prepared for all the critics, I’m prepared for all the naysayers and the ya-da-ya’s," Winfrey says by telephone from Sydney. "The real truth is this: Everything I’ve ever done has prepared me for this moment, for this launch.

"I look at this launch as the birthing of a baby, not the raising of a child," she continues, managing expectations about the sure-to-be-low-rated early days of OWN. Child-rearing will mostly have to wait until after she tapes her final episode of "The Oprah Winfrey Show" in May.

"It’s a long-term process," she says, "and I have the vision to see what this network can be in three years, in five years, in 10 years, as an institution of hope and inspiration."

At its core, OWN will try to embody Winfrey’s "live your best life" philosophy, and it will aim at the same audience as her current show — women from the ages of 25 to 54, says Christina Norman, the channel’s chief executive.

But OWN’s three-year gestation has been unusually arduous. Early on, Winfrey’s partner in the joint venture, Discovery Communications, grew frustrated, and as boardroom tensions boiled over early last year she considered backing out altogether. The relationship has improved markedly since then. But as recently as late November, some producers working with OWN still doubted that the channel would actually come to life in January.

Now, without a doubt, it’s coming. But it brings clear risks for Winfrey. She is swapping her broadcast stage — where nearly 7 million fans watch her every day — for a cable platform that will be, at least at first, much smaller. For a time, she says, she lived in fear about the channel, even though she had fostered the idea for OWN for the better part of 20 years. And questions linger among some observers — like OWN’s future competitors at Bravo, Lifetime, WE tv and elsewhere — about her level of commitment to the channel.

Winfrey says she’s worried only about how well OWN is doing in "letting people know where the channel is." (This month, Oprah.com features an OWN countdown clock and a channel-finder tool.)

That aside, she says she’s pleased with her lineup of shows and the energy of OWN’s 140-odd workers.

"I’m about as calm as a person who’s about to give birth to such a humongous baby can be," she says.

Technically, Winfrey is adopting, not giving birth. With the flip of a control-room switch, OWN will replace the Discovery Health Channel in almost 80 million homes. OWN is hoped to be everything that Discovery Health was not: widely known, well supported and highly rated.

In the winter of 2007, the new chief executive of Discovery Communications, David Zaslav, surveyed the dozen channels that Discovery owned — he liked to call it beachfront real estate — for areas of growth. He concluded that the Discovery Health Channel should be first in line for remodeling. "For a couple of months, we were walking in circles," he recalls. "’What do we put on this great platform?’ The home run was, could we find something to put on that would break through the noisy and cluttered marketplace?

"If it was really strong," he adds, "then we could also get a subscriber fee."

Subscriber fees, which cable and satellite carriers pay to channels and then pass along in bills to their customers each month, have turned channel owners like Discovery, NBC Universal and Viacom into much-envied media powerhouses. But Discovery was earning only 2 to 7 cents a month per subscriber for Discovery Health, analysts estimate, making it merely a shack on Zaslav’s beachfront. By contrast, of Discovery’s three big assets, the flagship Discovery Channel earned about 33 cents a month per subscriber, according to the research firm SNL Kagan; TLC, about 16 cents; and Animal Planet, 9 cents.

Zaslav started contemplating a partnership. Benjamin Swinburne, a media analyst at Morgan Stanley, says that this strategy was unique. "Very few other media companies," he says, "are willing to take chips off the table and admit that they can do more with a partner than on their own."

Zaslav’s epiphany for an Oprah-branded channel came at his suburban New York home, while he was flipping through his wife’s copy of O: The Oprah Magazine, the hugely successful joint venture between Winfrey and Hearst. His wife, Pam, had a habit of attaching Post-it notes to its pages, which got Zaslav thinking about Winfrey’s enduring brand.

"Oprah and her magazine stand for this idea — a shared idea we all have — a shared hope we all have," he says, "of living your best life." He could think of no equivalent on cable television. After barely three months on the job, he requested a meeting with Winfrey through her agents at the Creative Artists Agency.

"I’ve got a big idea," he recalls telling them.

At that first meeting, in April 2007, Winfrey shared the origin of her own big idea. The name OWN, she recalls, first came up in a 1992 conversation with her life partner, Stedman Graham. Winfrey was bemoaning the confrontational talk shows that were in vogue at the time, "and Stedman was saying, ‘If you don’t like it, you should start your own network."’ He wrote down "Oprah Winfrey Network," and she noticed that the initials spelled the word "own."

Winfrey has given herself to cable once before, in a much more limited way. Ten years ago, she was a co-founder of Oxygen, an ambitious channel for women that also counted Geraldine Laybourne, Marcy Carsey, Tom Werner and Caryn Mandabach as backers. The channel couldn’t find a voice or a loyal audience, and in 2007 was sold to NBC Universal, where it is now best known for reality shows like "The Bad Girls Club."

"As we all know, that didn’t work out for me," Winfrey says of Oxygen. "It was a great lesson for me: Don’t partner when you’re not allowed to be in charge and make a decision."

At Oxygen, she was an investor; at OWN, she is the chairwoman. The partnership with Zaslav, she says, "has been ideal."

(Discovery has entered into two other joint ventures since OWN was conceived — one with Hasbro for a children’s channel called the Hub and another with Sony and IMAX for a 3-D television network.)

For the 50-50 joint venture with Winfrey, which was announced in January 2008, Discovery proffered its health channel and $100 million in startup cash. Winfrey contributed her brand name, her 25-year library and her website, Oprah.com.

Crucially, the deal did not call for Winfrey to give up "The Oprah Winfrey Show," the syndicated cash cow that had her under contract. Though the daytime pie was shrinking, Winfrey still had the biggest slice by far.

Once the partnership began, a long, hard slog ensued. Executives came, executives went. So, too, did concepts for shows. A vague 2009 premiere date was pushed back, and then the partners stopped giving a premiere date at all. The channel was paralyzed.

All the while, Winfrey kept her distance. She had 130 hours of her talk show to tape each year, so she had committed to only 35 hours of original programming on OWN. Investors wondered if her heart was in it — and sometimes she wondered the same. "The first year, I’d go to meeting after meeting and I’d see all these sorts of promo materials put together of what OWN could be," Winfrey recalls. "Finally I said: ‘I’m tired of talking about what it can be; I want us to actually do something."’

Winfrey persuaded the former Viacom chief Tom Freston to be an adviser. Amid an executive reshuffling at OWN at the end of 2008, Freston helped to bring in Norman as the chief executive. Together, they became Winfrey’s cable television tutors — and the building blocks for the channel that viewers will see in January. (Freston, who is fond of exotic travel, is working for OWN part time, giving rise to a joke at the network that "the only person living their ‘best life’ is Tom.")

"It takes a while to get a team right," says Norman, playing down the false starts.

Freston reiterated that in a separate interview. "I don’t think it’s unlike what would happen at a normal startup," he said.

OWN’s lowest point was in April 2009, when the joint venture was almost scuttled. In another Chicago meeting with Winfrey, Zaslav painted a bleak picture of the advertising market, which had deteriorated during the recession. Then, turning more rosy, he proposed that OWN could be a much bigger business if she was accessible to viewers only on cable. In essence, he pressed her to commit or quit.

"I think what Zaslav would have wanted, ideally, was for me to take the ‘Oprah’ show to cable," Winfrey says. "But I felt like the show had its day, its moment, its time."

In the fall of 2009, as Winfrey began another season of her talk show, OWN still lacked a premiere date. Backstage, there was a gnawing suspicion in the television industry that OWN was doomed. But, undeterred, Norman’s team was working on pilots for reality programs of all stripes, all of them with themes that would fit right in on an afternoon of "Oprah": Take charge of your life, look beyond yourself, and "dream it, do it."

"This brand and this network are really about asking people to fulfill themselves," Norman said in August 2009.

Then, in November, everything changed. More than anything else, what OWN needed was someone who understood Oprah and her audience, and in the first week of that month, that’s what it added: one of Winfrey’s most trusted producers at Harpo Productions, Lisa Erspamer, was named chief creative officer. That was a tremor on the broadcasting landscape. The earthquake came two weeks later, when Winfrey told her adoring audience that she would be ceasing her daytime talk show.

Now OWN would be quite literally her next act — and her only act.

Looking back, Winfrey says, "I would have wanted to bring more people from my Harpo team" to OWN, Erspamer among them. "I think if I had been able to do that, I think this process would have gone a lot faster."

But, she continues, "I had the ‘Oprah’ show to finish; I had obligations, responsibilities; I wanted to end it in the best possible way."

Discovery promptly rewrote its contract with Winfrey. She would not re-create her talk show on cable, but she would appear for at least 70 hours a year, up from 35 in the original contract. She would travel the world for an interview series called "Oprah’s Next Chapter," to be shown in prime time, and she would pop in to other shows, like "Your OWN Show" — a reality competition to groom the next Oprah, with the winner getting a gig on OWN, naturally. The channel would start on Jan. 1, 2011, allowing for nine months of overlap between the talk show and the cable channel.

Overnight, OWN had become a much more ambitious endeavor. "The kind of programming we are producing is certainly different from what the original expectation was," Norman says now, citing her plan for 600 hours of original programming in 2011 and another 600 hours of acquired programming, like old episodes of "Trading Spaces." The original plan, she acknowledges, called for a lot less of each.

In the short run, that ambition ended up costing Discovery, but executives there are confident that Winfrey’s deeper commitment will make the asset more valuable over time. In August, the company lent OWN a further $89 million, which is to be paid back with interest as soon as the channel turns a profit. Five years from now, Winfrey can start to sell parts of her stake in OWN, in 10 percent increments — up to a certain level, while maintaining a minimum ownership stake — according to three people with direct knowledge of the deal who requested anonymity because the terms had not been made public.

More immediately, after 25 years on free over-the-air television, the Queen of All Media is effectively prying open the cable cash register. "By putting a subscriber fee together with this 80-million-subscriber platform, we have a chance to create some real value — big value," Zaslav says.

Norman, who worked at MTV and VH1 for 17 years, put it another way: Fees, she says, are "the mother lode."

Years ago, Discovery executives imagined earning 50 cents per subscriber for OWN. That could happen someday if Winfrey’s viewers flock to the channel, some analysts say, but expectations have been tempered for the time being. In current negotiations with carriers, OWN is offering a free year or two before starting a 20- to 30-cent fee per subscriber, according to the people with direct knowledge of the terms.

Some distributors have agreed to those terms, but others are balking, at least at the moment. While OWN could turn a profit by 2013, Swinburne said, "this is going to take five years to become really meaningful to Discovery’s stock." His current forecast for OWN has the channel posting $220 million in revenue at a 34 percent profit margin by 2015.

For OWN, the priority now is getting the programming right — finding the channel’s "voice," in television-speak. "It will take us a while," Zaslav says. Discovery Health ranked No. 41 among women 25 to 54 this year, and he would like to see its replacement creep up that chart each year.

So Winfrey’s baby will start out taking baby steps.

As if to rebut concerns about her commitment, all the parties involved say that she has been intimately involved in the programming. The tent-pole series, on Week One, will be "Master Class," a series of profiles of moguls and personalities like Jay-Z and Diane Sawyer that features Winfrey in each episode, and "Season 25: Oprah Behind the Scenes," a weekly documentary about the making of her existing talk show. But she "will not be on in a substantial role until September," Freston cautions, echoing other executives who say the channel should be judged not by its first week, but by its first year — or its second. Or its third.

"By 2013, we should be cracking," Winfrey says when reminded that 2012 would be her first full year of "Oprah’s Next Chapter." Because of her talk show, she says, "I have not been able to devote the amount of time and energy that I could and should be able to do in the future."

Already, the "Oprah" show has been a test-bed of sorts for OWN, as it was in May when Winfrey was interviewing Sarah Ferguson, the Duchess of York, who had been caught on camera a month earlier selling access to her former husband, Prince Andrew. Ferguson’s reputation was in shatters, and she was nearly in tears.

"I just had this epiphany," Winfrey said to Ferguson. "You on that tape — that is a spiritually, morally bankrupted person."

"That’s genius," Ferguson responded, moved by the encounter.

Winfrey almost immediately imagined an OWN show about Ferguson rebuilding her life. She recalled calling up Norman and saying, "I don’t want to ask her, but I think that this would make a really great TV show."

The resulting documentary series, which Winfrey named "Finding Sarah," is upbeat and inspirational. And, it features two of Winfrey’s friends, Dr. Phil McGraw and Suze Orman, helping Ferguson piece together her life.

OWN will also feature repeats of the syndicated "Dr. Phil" and, come September, reruns of "The Oprah Winfrey Show." Other "Oprah" regulars like Gayle King, Peter Walsh and Dr. Laura Berman have their own shows on the cable channel’s schedule, and in September, the former talk show star Rosie O’Donnell will return to daytime with an as-yet-untitled OWN talk show.

Amid this talent hunt, Winfrey has become a roving ambassador for the network, and has further cemented her link to its success — or failure.

For a moment in the telephone interview, she sounded as if she was giving away TV shows as if they were Pontiacs, as she so famously did for an entire studio audience in 2004.

"I look at everything now through the prism of, ‘This could make a very good TV show!"’ she says. At a recent dinner, she says, that’s what she kept thinking as she chatted up Bono of U2.

"Would you like a TV show?" she asked him.