A year after passing an ordinance limiting the height of church steeples and bell towers, Bloomington has tweaked its regulations by imposing design requirements to make it clear that the same bell tower can't be replicated over and over again on church grounds all over town.

It's not that churches have gone mad for bell towers. The new rule is aimed at providers of cell phone service who are looking for places to hide wireless antennas in residential areas.

After T-Mobile last year masked its equipment in a simple three-legged bell tower erected at CrossPoint Church near 98th Street and France Avenue, the company came back to the city and proposed more towers. When it suggested that the new towers might be copies of the one at CrossPoint, city officials got busy drawing up the new ordinance.

"What we don't want is cookie-cutter tube towers," said Bob Hawbaker, the city's manager of planning and economic development. "We need to figure out creative ways to allow wireless providers to penetrate residential areas without putting up a lot of ugly towers in neighborhoods."

That's why church steeples and bell towers have become popular places for wireless providers to hide their antennas. Mark Wilson, T-Mobile's external affairs manager for the region that includes the Twin Cities, said by phone from Chicago that the problem has gotten bigger now that an estimated 15 percent of Americans have dumped their land lines in favor of cell-service only.

When cell phone is the only way to reach 911 or other essential services, he said, that makes it even more important for wireless providers to make sure that there are no dead zones in residential areas.

But cell towers can reach as high as 45 feet to 65 feet, making them difficult to hide in neighborhoods that are mostly houses.

"It's difficult to install a new monopole [antenna] in a residential area, so we're always looking for creative ways to provide that coverage," Wilson said. "We've used smokestacks on schools, steeples on churches. They're very successful."

Wilson said Bloomington's new requirement that bell towers or steeples must be architecturally compatible with the church buildings and not be copies of other towers in the city will make it more expensive for his firm to design and build those towers. (Hawbaker said a bell tower that hides a wireless antenna can cost $250,000.) But Wilson said he doesn't object to the city's new rule.

"Our main objective is to provide the best quality coverage for our customers," he said. "Bloomington has been open to working with us, so we're happy to be working with them. If they want more architectural diversity and bell towers that are more architecturally harmonious with churches, we can do that."

Bloomington has two cell towers hidden in church bell towers or steeples. A third has been approved, and at least three more proposals are expected, city senior planner Glen Markegard told the City Council recently.

While the actual antennas hidden in towers are fairly small, the accompanying equipment on the ground that must be hidden and protected can range in bulk from three refrigerator-sized boxes to a single 12-by-20-foot unit.

Bloomington's poster child for good design is a Verizon antenna that's proposed for Oak Hill Lutheran Brethren Church at 90th Street and France Avenue. The antenna would be hidden in a brick bell tower joined to one end of the church building, matching the existing architecture.

Verizon "knew the ordinance was coming and hired an architect," Markegard told the council. "The church and the city were holding out for a good design."

The Rev. Nick Mundis said Verizon must get the city's approval for the tower before his congregation votes on whether to accept it. Verizon would build the tower and pay the church monthly rent, but the church also would have to commit to keep the equipment there for a number of years.

Verizon and its architect made a presentation to the church council, and the plans were well-received, Mundis said. "It does look really nice."

Mary Jane Smetanka • 612-673-7380