With its cobblestone streets and 18th-century architecture, Charleston is a living portrait of simpler times - an image that has made the city one of the most popular travel destinations in the world.
Amid so much history, the digital age seems a foreign concept. But it's not magic that lets visitors map their way through South of Broad on their smartphones, or allows Market Street merchants to use iPads as wireless cash registers.
Those connections are powered by a network of wireless infrastructure that, for the sake of historic preservation, has been melded almost seamlessly into the landscape of Colonial-era buildings and church steeples in the past several years.
There are a few conspicuous telecommunications towers in downtown Charleston, such as the one on Charlotte and East Bay streets, that broadcast signals of all types. But many cellphone carriers' antennas are stashed on the rooftops of some of the oldest and tallest buildings in the city, striking a creative balance of historic preservation and modern connectivity.
Other antennas are concealed in what are called stealth towers, which are essentially decoy structures such as signs, flagpoles and even fake trees.
"Basically, cellphone technology is radio technology. A cellphone is basically a two-way radio, and the technology is really several radio cabinets that are attached to antennas," said Mark Wilson, spokesman for T-Mobile. "The challenge is to make the antennas as visibly unobtrusive as possible. Usually the best method is to put them on a roof, but sometimes we will use camouflage technology whereby we will put them in a church steeple or in a sign, or things of that nature."
Karen Schulz, a spokeswoman for Verizon Wireless, said the company has a number of towers hidden in flagpoles and other decoy structures around the city. She said she couldn't specify their locations for security reasons.
"It's really interesting because we can do a lot with towers these days that we've not been able to do before," Schulz said. "There are definitely more options now when we are servicing really historic locations or highly dense populations."
Wilson said most companies generally prefer to use existing rooftops for their antennas.
"It's less visibly obtrusive, it's frankly a little bit cheaper, and oftentimes it's an abbreviated zoning process," he said.
Several of downtown Charleston's tallest buildings, including the Francis Marion Hotel, the Mills House Wyndham Grand Hotel and the Fort Sumter House, lease space on their roofs to a third-party telecommunications operator such as American Tower Corp. Those operators develop the infrastructure needed for radio transmission and sublease it to multiple cellphone carriers.
Felcor, the management company of the Mills House, earns about $150,000 in additional revenue each year for leasing rooftop space to American Tower Corp, said Felcor spokeswoman Abby Salami.
She called it "a very symbiotic relationship" because providing rooftop space allows wireless phone companies to meet the city's design restrictions, while the hotel can profit from space it wouldn't use otherwise.
"There is no monitoring of the companies, or anything like that. We just provide American Tower Corp. with the space to lease and they handle everything else," she said.
While it may be easier to get the city to approve a rooftop antenna rather than a new stealth tower, the approval process still can be a speed-bump to the rapidly changing industry.
In Charleston, any changes to historic buildings, even to the rooftops, must be approved by the city's architectural review board. So, cellphone carriers are routinely applying for permission to upgrade their rooftop facilities to keep up with their competitors.
"People are now relying on their wireless phones for everything. ... And the explosion of data use is almost beyond comprehension," Wilson said. "T-Mobile and most other carriers are in the process of upgrading their communications networks really in response to consumer demand."
Schulz and Wilson said their companies don't feel restricted by cities' design rules, however, because most municipalities understand the importance of providing widespread coverage.
"Governments understand how critical wireless infrastructure is," Wilson said. "There must be roads, airports and electricity, and there also now needs to be wireless access. It creates and supports an enormous amount of jobs, and so I think it's in everyone's interest to increase and accelerate that connectivity."
Reach Abigail Darlington at 937-5906 and follow her on Twitter @A_Big_Gail