On Monday's "NBC Nightly News," a weather-beaten David Bloom had a dramatic story for Tom Brokaw from Iraq:

"A couple of hours ago, we came under a brief Iraqi artillery or mortar strike," Bloom said in a green-tinted picture, perched atop his tank recovery vehicle. Suddenly there was footage of Bloom that had played a few hours earlier on MSNBC: "We're under attack right now!"

Across the dial at MSNBC, Sen. John McCain was discussing war strategy with Chris Matthews, while on CNBC, Forrest Sawyer was interviewing Peter Arnett in Baghdad. A moment later, Brokaw was chatting up Arnett for the NBC newscast.

While all the networks are on a 24-hour war footing, only NBC is blanketing the airwaves with a three-pronged approach that milks every drop of its operation. "Our people are exhausted," says David Verdi, executive director of NBC News, who acts like an air traffic controller from the Secaucus, N.J., control room. "Everyone wants Bloom all the time."

And Bloom, 39, a White House correspondent turned co-anchor of "Weekend Today," is trying to accommodate them. "Given the fact that we're filing at all hours of the day and night, you try to pace yourself and get a little bit of sleep," Bloom says from Iraq, where he's embedded with the Army's 3rd Infantry Division. In his M88 tank vehicle, "you're sleeping with your knees propped up around you."

Unlike the news divisions at CBS and ABC, which are largely reduced to updates if their corporate bosses put on soaps, sports and sitcoms, NBC can showcase its top people on two cable outlets. "We're greater than the sum of our parts," Brokaw says. "We don't have to stop and start. We're up and running at all times.

"No one wishes a war on the world, but when a large event like this happens, as it did with 9/11, it allows us to consolidate our resources."

NBC News President Neal Shapiro says the triple-team approach "is encoded in our DNA now." The seamless switching back and forth "to me is a technological miracle. . . . If people didn't get to see David Bloom's report on 'Nightly News,' it's not going to vanish into the ether."

If the NBC honchos sound as if they're gushing over Bloom, that's because they're thrilled with his boyish enthusiasm and the mobile satellite platform that transmits crisp pictures at up to 50 mph. Other network stars are emerging as intrepid war correspondents -- ABC's Ted Koppel, CBS's Scott Pelley, CNN's Walt Rodgers, Fox's Oliver North -- but Bloom is seen zipping through the desert so often that he's become Iraq's unofficial travel guide.

On Monday, for example, Bloom was on at 2:22 a.m. (MSNBC), 6:35, 7:09 and 8:04 ("Today"), 10:43 (NBC), 10:47 (MSNBC), 11:12 (NBC), 12:31 p.m. (simulcast on NBC and MSNBC), 12:36 and 2:33 (MSNBC), 6:37 ("Nightly News"), 8:07 and 9:35 (MSNBC) -- talking about everything from Baghdad invasion routes to tension among the troops.

Yesterday Bloom was wearing goggles, tan fatigues and suspenders as he reported from a sandstorm, his thick shock of graying hair whipping in the wind. He hit MSNBC so often that the network assembled a collage of his hour-by-hour appearances, and Brokaw replayed the report in an NBC noontime special.

But cable is a voracious beast, and Bloom's subject matter -- some Army mechanics trying to fix a Bradley Fighting Vehicle engine yesterday -- can seem less than momentous when there's no fighting going on.

"We're here to tell the soldiers' stories," Bloom says. "There's a deep yearning on the part of the American people to understand what it's like for these soldiers. If we come back a couple of hours later and the guys are more beaten down by a sandstorm, I think that's news. Man, the sacrifices these soldiers are going through, whether you believe in the merits of the war or not."

NBC, with its mass audience of millions, casts a far bigger shadow than the niche cable channels. If Arnett is reporting on MSNBC and bombs start falling in Baghdad, he is quickly switched to the broadcast network.

In putting together "Nightly News," says Brokaw, he is very conscious of MSNBC: "I keep my eye on what they're doing all day long so we can take the best of that for our broadcast, along with what we're doing independently. It keeps our military analysts and commentators on top of their game as well."

As for the fatigue factor, Brokaw says: "Adrenaline is a powerful drug."

It helps to have a backup act. NBC frequently picks up the MSNBC war feed, particularly in the late-night and early-morning hours. If Brokaw is anchoring live coverage during the day, he can take an hour off to prepare for the evening news while NBC picks up MSNBC'S Brian Williams from Kuwait to fill the gap.

At the same time, NBC is using its top-rated news division to try to boost its weaker cable partners.

MSNBC, which has a news alliance with The Washington Post, has been a perennial also-ran in the cable wars, trailing Fox and CNN by substantial margins as it constantly changes identities. Just before the war, the Microsoft-NBC network dumped liberal Phil Donahue and hired a number of conservatives, including former House majority leader Dick Armey and radio talk show host Michael Savage.

If viewers are exposed to such MSNBC anchors as Lester Holt and John Seigenthaler, while checking out its war coverage, Shapiro says, "that's bound to have a halo effect."

CNBC is primarily a business channel whose ratings have dropped from Wall Street's peak in 2000, but it is doing plenty of Pentagon updates and war talk during the day (such as the impact of past wars on stock prices) before switching to war-saturated talk shows at night.

When the first cruise missiles hit Baghdad last Wednesday night, NBC beat the other broadcast networks by drawing 18.2 million viewers, plus 4 million on MSNBC (about half the viewership of Fox News or CNN) and 902,000 on CNBC. Some rival network executives are grumbling about NBC's decision to trumpet these numbers in a full-page New York Times ad, saying this was unseemly in time of war.

On Thursday night, NBC aired two hours of its most popular sitcoms, leaving analysts to wonder whether the cable alternative allows NBC to ghettoize its war coverage without jeopardizing its lucrative entertainment shows. Brokaw says he stays in touch with former "Today" producer Jeff Zucker, president of NBC Entertainment, and has been able to break into regular programming when necessary.

"As a news guy, you'd always like to be on," Shapiro says. On Monday night, when NBC aired "Fear Factor" and the Miss USA pageant, "there was nothing overwhelmingly compelling for prime time," he says. "We still generated a lot of good material" for cable.

Brokaw says he sympathizes with CBS and Dan Rather, whose coverage has often been shrunk to updates and cut-ins to accommodate the NCAA college basketball tournament.

"I know how frustrating that must be for him," Brokaw says. "They've got 100 pounds of capacity and five-pound bags to put it in. We don't have that problem."

David Bloom, left, and Brian Williams report on the war for NBC, MSNBC and CNBC; right, MSNBC anchor Lester Holt.Perennial Bloom: The reporter's dispatches appear on newscasts around the clock on one or another of NBC's three channels.