Bill Bracken hasn't had Thanksgiving off in years, but at least he can sleep late. He reports for work Thursday at 2 a.m. Most of his co-workers have to be there at midnight.

Bracken is the supervising producer of the Macy's Thanksgiving Day Parade telecast on NBC a TV event that stretches back a half-century.

This is the eighth year Bracken has joined executive producer Brad Lachman to create the paradecast, and, in between other projects (notably their "Jennifer Lopez in Concert" special that NBC aired Tuesday), they began planning their Thanksgiving feast in August.

Since then, they have rallied a crew of more than 100 NBC engineers, camera operators, sound technicians, lighting personnel and stagehands. They have welcomed back as hosts the Today show's Katie Couric, Matt Lauer and Al Roker. They have let anyone who asks know the 9-11 attacks won't stop the parade or influence how it's televised.

And in their temporary quarters at NBC in Rockefeller Center, they have faced the many challenges of this 75th annual cavalcade.

These include: 15 giant character balloons, more than two dozen floats, 12 marching bands, 21 themed clown groups, 14 entertainment groups, as well as celebrities, the Rockettes and, of course, Santa Claus all coursing down a 21/2-mile route from Manhattan's Upper West Side to Herald Square, where Macy's department store happens to be.

"This is not like covering something at an arena," notes the 41-year-old Bracken, who began his career as a That's Incredible! researcher. "And we can't say, 'Stop! Back it up!' Once it starts, that parade keeps coming, no matter what."

That's why, in the wee hours before the parade, almost every part of it is given a dry run. And that's why Bracken and his colleagues will have a long day.

From midnight to 3 a.m., crews set up final camera positions as well as the host platform at 34th Street and Broadway.

From 3 to 5 a.m., each band does a practice march through the Herald Square performance area.

From 5 to 7 a.m., a caravan of golf carts  each labeled as the float for which it's subbing pass before the cameras for a start-to-finish technical rehearsal.

At 7 a.m., ensembles from the four featured Broadway musicals rehearse.

At 8:15, the big opening number has a final run-through. Then, at 8:30, there's a practice ribbon-cutting uptown.

"Then everybody takes a break until 8:55," says Bracken, "and we're on the air at 9."

Couric, Lauer and Roker arrive about 6 a.m. after days of poring over a dictionary-thick briefing book organized with hard facts and giddy descriptions.

The hosts, Bracken says, "have to know what's coming in the parade, and they have to be able to adapt when something changes. They're not just reading the TelePrompTer. They've very much involved."

The parade starts at 77th Street and Central Park West, where five cameras cover the ribbon-cutting as well as interviews by Roker.

At 10 a.m., the procession reaches Herald Square, under the watchful eyes of Couric and Lauer. By then, Roker will have joined them after zipping downtown with a police escort.

There, NBC deploys 11 cameras as well as its encampment of broadcast trailers and trucks.

One trailer contains the control-room lair of Lachman, Bracken and director Gary Halverson (another Macy's parade veteran whose far-flung credits include Friends and Metropolitan Opera broadcasts). They will track the parade's progress, and make moment-to-moment adjustments to keep the show flowing and on schedule.

The occasional glitch adds to their fun. Bracken remembers how, one year, the audio board went kaput. Everything went silent just before a commercial break. That gave engineers 150 seconds to fix the problem. They did, with seven seconds to spare.

If they hadn't? "We could have routed all the audio through the mixing board of the separate music truck," Bracken says. "You have to have a backup."

Three hours after it began, the show is over. The broadcast is still unreeling on tape-delay for each of the westward time zones. But at 12:01 p.m. Eastern in the production trailer, "hopefully, there will be a lot of congratulations and backslapping," says Bracken.

A good show just another reason for him to be thankful.