To the casual observer, the man walking the halls at the Domain at Tempe apartment community looked like something out of a science fiction movie. Sure, the 300-unit building catering to students at Arizona State University had seen its fair share of OMG! moments in the hallways and common areas, but this was a little bit different: The visitor was walking at a slow, steady, measured pace throughout the community wearing a high-tech communications backpack that sported four different antennae, all of which connected into a tablet PC that generated real-time thermal images. Students wondered if this was security on the prowl for contraband space heaters, or perhaps an undercover agent looking for violators of the building’s no smoking policy?

As it turns out, the man in the strange suit was simply a cell phone service auditor, hired by the Domain’s developer, Ultimate Student Living (USL), to conduct a full-spectrum analysis of cell phone coverage on the property that included real-time, foot-by-foot data on reception for cell phone users who subscribe to AT&T, Sprint, T-Mobile, or Verizon as their primary carrier. “The auditing service is really cool,” says Jeff Horton, IT director for Ocoee, Fla.–based USL, a student housing developer with projects in Arizona, Indiana, South Carolina, Kentucky, Ohio, and Maryland. “The auditor takes a CAD drawing of the site and pre-plans an entire walk path through every floor, which is then linked to the computer via USB to an enhanced cell spectrum tester. The output is essentially a heat map of all four carriers showing decibel penetration at any point on the property.”

That heat map quickly told Horton that dead zones at the property were going to necessitate the installation of a distributed antenna system (or DAS, also commonly known as a repeater) in order to boost reception quality for Domain at Tempe’s residents. His predicament isn’t an isolated one: Multifamily apartment buildings have long struggled with cell phone reception in units that are typically encased in tons of steel, concrete, and other signal-blocking construction materials. Certain materials that have sprung from the green building movement—including low-E glass windows, which commonly employ metallic oxide coatings—can also hamper cell reception in smaller mid-rise and garden-style communities, so even as developers have sought to create smarter and more environmentally friendly apartment buildings, cell phone coverage has suffered.