YUMA - Pvt. Ashley Christopher, a member of the Arizona National Guard for only a year, and Sgt. 1st Class Henry Castillo, who has served more than two decades, reflect the diversity of Guard volunteers supporting the Border Patrol's Southwest border clampdown.

But they say all the guardsmen share a sense of mission, and none consider the new job to be a hardship.

"Just to wear the uniform is a blessing," said Castillo, 46, an ex-Marine with 26 years in the Guard. He was repairing a generator set Wednesday, one of a half-dozen guardsmen working in the Border Patrol's air-conditioned motor pool maintenance shop here.

"I've been on flood duties, fire duties, airport duties, any kind of duty they can come up with, I've volunteered for every one of them, and my employers are very good about that," Castillo said.

The plan President Bush outlined last month calls for placing 6,000 soldier like Castillo and Christopher in non-law enforcement roles assisting the Border Patrol along the 2,000-mile border with Mexico this year.

For up to two years, the Guard will take over support jobs that now tie up immigration agents, monitoring sensors, radios and border cameras and dispatching agents in the field to intercept smugglers guiding illegal immigrants and drug traffickers. Guardsmen also will work on improvements like fencing, lighting, roads or vehicle barriers while the Border Patrol recruits 6,000 more agents to beef up to about 18,000.

Arizona, with about 375 miles of the Mexican border, has been the nation's busiest entry point for illegal crossings. More than 300 Arizona National Guardsmen should be on duty by month's end, said Maj. Paul Aguirre, a spokesman for the state Guard, supplemented by hundreds from other states.

Across the entire border with Mexico, the goal is to have 2,500 troops in place by June 30 and 6,000 by Sept. 1, said Kristine Munn of the National Guard Bureau.

Munn could not provide a state-by-state breakdown, but officials said previously that Arizona was likely to receive 40 percent of the total. Most will be assigned within the larger Tucson sector.

Border Patrol officials say it's too soon to say how many agents will be freed up, though Yuma Sector Chief Ronald Colburn has said the ideal would be a one-for-one exchange - an agent on the line for every guardsman who arrives for behind-the-scenes work.

Nevertheless, the impact of the National Guard's arrival has been felt already.

"They've been a tremendous amount of help in shoring up our necessary infrastructure projects, and we believe they're already starting to show some impact here in the sector," said Border Patrol spokesman Chris Van Wagenen.

"They're very good guys. Each one of them seems to be very dedicated to what they're doing, and they seem quite pleased to be part of this project," he said. "It makes it very easy to work with them because they want to be here."

The motor pool crew certainly feels that way.

"We're all here to give Border Patrol and Customs whatever assistance they need," said Sgt. 1st Class Raymond Wong, a battalion motor sergeant - an Army-trained mechanic - from Phoenix, who was working with Christopher and a Border Patrol mechanic replacing worn motor mounts beneath a hoisted patrol vehicle.

"The better we work on their equipment, the better their equipment is, the better job that they will be able to perform out there, and safety is No. 1 for the agents out in the field," Wong said. "So that's our objective, to make sure their equipment is operational and safe for them to operate in the field and enforce the laws of our country."

In the Yuma sector's communications center, a combination of Border Patrol agents, civilian employees and other previously deployed National Guard members continuously monitor 25 cameras atop 50-foot poles that span the border from Andrade, Calif., to San Luis, Ariz.

Those assigned to the motor pool here include Spc. Rodney Paguia, a saxophone and bass player who is playing a different tune in Yuma - servicing vehicles - and Sgt. 1st Class James Allen, a federal correctional officer, guardsman for 22 years and a generator mechanic who served in Iraq with Castillo and also was there during the Gulf War.

"It's much better here than it is in Iraq," Allen offered.

For Christopher, 22, being deployed to Yuma isn't bad, and family and friends in Phoenix are only a phone call away as she bunks down in her hotel room each night.

"Sure, I could be hanging out at home, but you accept that when you join the Army," Christopher said. "We could be sleeping in tents, so it could always be worse."