Tenants at 165 Pinehurst Ave. have something most modern Americans would envy: impeccable cell phone service. But it comes with a cost. They worry their building in northern Manhattan is going to collapse. Their reception is so crisp because of two cell phone base stations and 20 antennas on their building's roof, sending and receiving thousands of calls each day for T-Mobile and AT&T. To the cell phone providers, this hub -- and others like it -- are essential to accommodating the explosion of mobile data and voice communications. But the tenants, as much as they like their clear reception, are in an uproar because they argue that their 82-year-old building cannot bear the weight of the base stations on its roof. 'Before this went up, we were told we couldn't come up here, because it wasn't stable enough for human weight,' Meg Gibson, a longtime tenant, said. The tenants did not mind much when the first base station, which belongs to T-Mobile, went up in 2006, but grew concerned when the second one, owned by AT&T, was installed last fall. Gibson said her roof had a 'chronic problem' of disrepair, and alerted the city to her concerns. The Buildings Department issued a notice of violation to the landlord, Shahram Mobasser, for failing to maintain the buildings' walls, and, in a report, noted four large cracks beneath the base station's support beams, though a city engineer concluded that it was hard to determine the cause of the cracks. The Buildings Department approved the landlord's application to erect the AT&T base station last summer, after determining, a spokeswoman said, that the plans complied with the building code. The tenants are suing the landlord for allowing the stations to be installed. But industry experts said it was highly unlikely that the base stations were causing the structural harm that the tenants claim. Roger Entner, a wireless industry analyst with Nielsen, said the cell phone antennas were relatively light and the base stations not unduly heavy. 'The base station only weighs a couple of hundred pounds -- it's like three fat men,' he said. 'If that is cracking the stuff, the building has way bigger problems.' Representatives from T-Mobile and AT&T said they were exacting in installing equipment safely, with the approval of structural engineers and in accordance with building codes. By law, the ultimate responsibility of the building's maintenance falls with the property owner, a spokeswoman for the Buildings Department said. 