"The main reason for the gap is probably availability," Horrigan said. "However, rural users are adopting broadband at a faster rate than urban and suburban ones."

For increasing numbers of rural users like Thompson, adopting broadband means using fixed wireless. Such service is usually supplied by small, local Internet service providers that rely on unlicensed versions of Wi-Fi that have increased power levels and are tuned to avoid interfering with licensed devices. The subscriber is given a radio and mounts a fixed antenna with a line of sight to the provider's transmission antenna, which usually has a range of six to eight miles.

There are a couple thousand fixed-wireless providers in the U.S., most of them mom-and-pop operations with a few hundred users, explained Tom Sanders, head of The Final Mile Inc., a consulting company in Asheville, N.C. They often barter for antenna space on hilltop houses, otherwise charging between US$50 and $75 monthly for as much as several megabits per second of wireless connectivity.

"Every one of the providers say they have more callers than they can serve," Sanders noted.

"We continue to see a subscriber growth of 10 percent or greater every year," agreed Douglas Campbell, vice president of AMA TechTel Communications. Based in Amarillo, TechTel covers 20,000 square miles in west Texas and eastern New Mexico, and it takes Campbell six hours to drive across the coverage area. In terms of subscribers, TechTel is also one of the largest fixed-wireless Internet service providers, with 18,000 subscribers (including Thompson and Clarendon College) in an area of about 66,000 households. Residential subscriptions start at $44 monthly for 512Kbit/sec., and the fee covers the customer's antenna and radio, Campbell explained.