The broadcast nets would like to think of themselves as all-embracing, capable of casting as wide a net as necessary to snare the next smash.

But when it comes to developing, producing and scheduling a hit series, each has its limitations.

For better or worse, the Big Four broadcasters possess fairly immutable strains of DNA, and while each offers examples of brand-busting hits (think “American Idol” on counterculture Fox), certain shows simply have a better chance at succeeding on certain networks.

It’s hard to imagine “Everybody Loves Raymond” doing as well on a net other than CBS, “Friends” flourishing away from NBC or “Prison Break” busting out anywhere but Fox.

Landing the right show on the right net, then, is an important part of the “hit” equation — but the best fit isn’t always the most obvious suspect.

As 20th Century Fox TV president Gary Newman says, success also rides on who wants a show most.

“Every net has a show working that you wouldn’t necessarily think of them first,” he says. “It’s more important than ever to land a show at the right net, but it might be the right net because of their passion and commitment for the project.”

He adds that the decision on a network begins with the pitch, following discussions with the writer.

“We have conversations about where we see it fitting in, and typically have a best place in mind,” Newman says. “We may go to a network preemptively, but more often we shop it.

“It’s not until you sit in the room and gauge their reaction and the questions they ask that you know where it should go.”

Another studio exec says he’s recently seen more examples of nets not wanting to be pigeonholed.

“They’re now all after the same 18-49 audience,” he says. “It’s not as simple as saying a traditional show goes to CBS or a hip show to NBC.

“They’re bound to overlap, and they do.”

Over the years, CBS could count on a core following among older viewers and strength outside of the big cities, while ABC fared well in bigger cities while also appealing to suburban families. NBC has come to excel among urban, affluent white-collar crowds, and Fox consistently skews younger and more male.

But these road maps don’t always lead to success, and a hit show can redfine a struggling net.

A rudderless NBC, for example, hadn’t developed a hit drama for years until it connected with an unlikely one, “Heroes,” last fall.

The tale of ordinary people with extraordinary powers instantly became not only the net’s youngest drama but also its most male-skewing — this in a fall when NBC also launched the glossy “Studio 60 on the Sunset Strip” and “Kidnapped,” which fared well among upscale auds but drew puny overall numbers.

“Heroes” paired with “Deal or No Deal,” a not-so-upscale gameshow, to give NBC its strongest night.

Tim Kring, creator of “Heroes,” believes his was the right show at the right time for NBC.

“I think the fact that they found themselves suddenly having gone from first place to fourth, they were very willing to take a chance on what was seemingly a bold idea,” Kring says. “And I think it was really important for them to try and reinvent and go for a different audience.”

(The “Heroes” success has informed the net’s fall roster, with NBC adding a time-traveler drama and a new take on “The Bionic Woman.”)

Joining “Heroes” as rookie successes of the 2006-07 season were a pair of ABC series — “Ugly Betty” and “Brothers & Sisters” — that fit perfectly into a brand that crystalized with “Desperate Housewives” three years ago.

The audience for both “Betty” and “Brothers” is heavily female and upscale, and they tap into the comedy and family elements that worked with “Housewives.”

While NBC hasn’t produced an upscale hit scripted show in recent years (excepting “The Office”), ABC has excelled and is now the leader in these categories.

At CBS, the desire is to break out of the creative cul-de-sac the net created for itself as a result of devoting well over half of its schedule to crime-solving procedurals.

“It’s a case of the 80/20 rule, where 20% of the audience is contributing to 80% of the ratings,” says Brad Adgate, an analyst at research firm Horizon Media. “You want to put on something that viewers outside your core might find (while) channel surfing.”

“Jericho,” about a Kansas town coping with the aftermath of a nuclear bombing, was a step in that direction this past season, but its serial format didn’t go over well with Eye auds that had grown accustomed to neatly resolved endings.

Fox, whose key scripted shows remain edgy (“24,” “The Simpsons,” “House”), struggled with its development last season, most believe, because series like courtroom drama “Justice” and domestic comedy “Happy Hour” were too generic.

And while it has seemingly returned to its roots with fall shows like the “Terminator”-inspired “Sarah Connor Chronicles” and “New Amsterdam,” about an immortal detective, it’s playing it safe in comedy. “Back to You,” starring Kelsey Grammer and Patricia Heaton as bickering news anchors, is about as un-Fox as you can get.

“Of all the nets, they’re not as concerned about their mold,” says Adgate. “Maybe because they’re younger, they will try stuff and are more likely to go in another direction.”

Newman of 20th, which produces “Back to You,” admits that “CBS seemed like the natural place for it,” but that Fox “blew everyone away with their passion and financial commitment.”

Whether it works as well on Fox remains to be seen, and Newman still laments that another of his studio’s comedies, Reba McEntire starrer “Reba,” never realized its full potential.

“The WB didn’t really know how to communicate with advertisers or expand their audience to make it work,” he says. “I’m convinced that it could have been a big hit on CBS or ABC.”