This fall's TV schedule will be full of twenty-somethings looking for love, singers searching out fame and dinosaurs hunting down dinner -- and if that's not enough, there promises to be a heap of drama behind the scenes.

What unfolds at NBC and ABC will be among the most closely watched developments of the 2011-12 season. Both have relatively new entertainment chiefs in Bob Greenblatt and Paul Lee, who made major changes to their prime-time schedules in hopes of resurrecting ratings and satisfying management at Comcast Corp and Walt Disney Co.

Fox and CBS, with stronger schedules, will be under less scrutiny, but all four broadcast networks could feel the heat from advertisers who signed pricey deals for commercial time. Last spring, during the dealmaking period, commercial rates rose around 10 percent from a year earlier.

The trouble is that concerns over the economy have intensified since advertisers made those deals -- today there is far more talk about a double-dip recession -- and they could be taking a hard look at spending plans.

Along Madison Avenue, anticipation is running high for The X Factor, a new musical competition from Simon Cowell that Fox hopes will be a blockbuster along the lines of American Idol. Advertisers paid up to $400,000 for 30-second spots and it boasts a clutch of blue-chip corporate sponsors, including Pepsi and Chevrolet.

Other shows that are generating buzz -- for better or worse -- include ABC's Pan Am and Charlie's Angels, NBC's The Playboy Club, Smash and Prime Suspect, and Fox's Terra Nova, a costly Steven Spielberg-produced dinosaur drama burdened with high expectations.

Last year, more than three-quarters of the new shows were canceled and several barely lasted a month, the most notable being Lonestar, a high profile con-man drama that Fox abandoned after two episodes.

Look, all these guys are under pressure, said Brad Adgate, senior vice president of research at advertising firm Horizon Media. You get next day ratings and must immediately make million dollar decisions. Every day there is a hero and every day there is a goat. But there's probably more pressure on ABC than anybody.

Now president of ABC Entertainment, Lee spent 7 years running ABC Family until he was promoted in July 2010. This is his second full TV season running ABC, but the first one in which he's been involved from development through scheduling.

Lee can bank on the popular comedy Modern Family and Grey's Anatomy is still a top rated drama, but this will be the last season of the long-running Desperate Housewives and there are already some major holes in the lineup.

His problem is that there aren't a lot of building blocks there, said David Scardino, entertainment specialist at media agency RPA. I don't know how much patience Disney is going to have with him.

NBC's Greenblatt, meanwhile, should have some breathing room. Comcast hired him away from Showtime, where he had a solid track record, and has indicated it does not expect to revive NBC's fortunes in one season. For 2011-12, Greenblatt will bring out a hefty 12 new shows, including Smash, a midseason musical set on Broadway that will star Katherine McPhee from American Idol.

Comcast is at least paying lip service to the fact that this won't be turned around overnight, Scardino said.

The biggest surprise of the TV season may be if either ABC or NBC manage to move up in the ratings. That would mean beating out either News Corp's Fox, with several blockbuster hits, or CBS Corp's CBS, with the strongest top-to-bottom schedule in the business.

Another shocker would be if the four broadcast networks can arrest the steady decline in their collective audience.

One reason for the drop in viewership at the broadcast networks is the increasing competition from cable TV, with its critical and popular hits such as Mad Men, Breaking Bad, and Justified. Advertisers are well aware of the trend and swallowed huge price increases from the cable networks during the spring negotiations.

It remains to be seen whether advertisers will start to back away from pricey deals in general, exercising options that allow them to cancel.

There is always a lag between what the economy is doing currently and where the budgets are -- since budgets are done early, said Scardino. If I was on the network side, I would be nervous.

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