A Cell Tower of Your Very Own

Major Carriers Sell a Personal Device That Improves Signal

Up until a few weeks ago, Mike Gillin was a tough man to get a hold of.

His basement apartment in Smithtown, N.Y. is a virtual black hole for cellular signals. AT&T Inc.'s cellular service is just good enough that Mr. Gillin's iPhone would ring when dialed—but the calls would usually fail to connect. Text messages would arrive hours, or even days, late. Friends trying to reach him would have to switch back and forth between dialing his land line and his cellphone in an effort to get through.

"It was always a process of calling one number, and then the other and hoping I answered one," says Mr. Gillin, 35-year-old email systems manager. "It was always a pain."

So it's no wonder that in May Mr. Gillin jumped at the chance to buy AT&T's 3G Microcell—a textbook-size cellphone gadget known as a femtocell that helps with unreliable cellular service. Think of it as a personal cellphone tower. It operates on the same technological principle, receiving an incoming call signal via the home's DSL or cable Internet connection, and then broadcasting the signal to the user's cellphone.

Never heard of a femtocell? Many other cellphone users haven't, either. Major cellular carriers do virtually no advertising for the devices—a rare example of reticence in an industry that spends heavily on ads. Industry experts say big carriers are reluctant to highlight a product that calls attention to the problem of spotty network coverage.

AT&T has been rolling out the 3G Microcell, which provides a full signal to a surrounding area of up to 5,000 square feet, as an answer for customers in areas with poor reception. The price is $149.99.

Verizon Wireless's femtocell, the "Network Extender," is priced at $99.99; Verizon doesn't sell it in stores. Sprint Nextel Corp. sells its Airave for $99.99 with a mandatory $4.99 monthly charge to customers who ask a service representative. T-Mobile USA doesn't sell the device.

The carriers say they put limited marketing behind the devices because they don't see them as mass-market products, although useful in certain situations. "It is designed largely for customers who—because of architectural issues or location geography—want enhanced calling," a Verizon spokesman says. Sprint says the femtocell "helps enhance" coverage and notes there are situations where reception problems are out of the carrier's control. AT&T says it plans to offer the 3G Microcell in a direct marketing campaign to customers facing unique physical or geographic obstructions.

The carriers have been sensitive to criticism of poor coverage and the propensity for dropped phone calls. AT&T still faces reception issues in New York and San Francisco, largely due to the popularity and data- hungry demands of Apple Inc.'s iPhone. AT&T says it is working on improving coverage in those areas, and expects to have upgrades in both cities later this year. The two cities were among the first to get the 3G Microcell following the April launch. AT&T's device improves signals for both data and voice; those from Verizon and Sprint boost only voice quality.

As for the devices' potential health risks, some experts say they are probably no worse—and may be less—than the still-unproven risks posed by regular cellphone signals. Industry observers note femtocells are no more harmful than the typical Wi-Fi hotspot, and may be less harmful than a cellphone because they aren't held close to the body.

"At this point, there's no conclusive evidence showing all these radio signals are hurting people," says Harry Wong, analyst at research firm Parks Associates.

Film director Barry Sonnenfeld purchased Verizon's Network Extender nearly a year ago for his East Hampton, N.Y., house, which doubles as a home theater where he screens projects. Mr. Sonnenfeld, who uses three major wireless carriers—Verizon Wireless for his BlackBerry Bold, AT&T for his iPhone and Sprint for his Evo 4G—says service is bad in the area. "Verizon is sketchy and AT&T is profoundly bad," says Mr. Sonnenfeld. He says with the Verizon device, the BlackBerry has full bars; he says he is planning to buy AT&T's device, too.

Femtocells can be a pain to set up. Activation can take up to 90 minutes, and Mr. Gillin says he occasionally has to reboot it. And because the device relies on a global positioning system to confirm its location in a service area, it needs a clear line of sight to the sky.

The devices have to be in areas where the carrier already offers service, so they won't work overseas. AT&T, on the first weekend after the launch of the iPhone 4 last month, had a system outage that left some 3G Microcells from activating.

For customers on limited-call plans, the carriers also offer an option to pay an additional monthly fee and get unlimited calls using the femtocell. Some consumers have bristled at paying extra to improve what they believe are the carriers' own coverage problems. The carriers say fees cover the cost of running wireless traffic from the femtocell back to their networks.

Some people who have the devices say the improved service is worth the cost. David Nowicki, a marketing executive for Airvana Inc., which is working on a data femtocell for Sprint, says he personally uses all of his competitors' devices because his North Andover, Mass., home sits between two hills that interfere with cellular signals. "You have a part of the network that's dedicated to you," he says.