WiMax at a thousand feet in the Big Apple (photos)

CNET took a behind-the-scenes tour at the top of the Empire State Building in New York City with TowerStream, a company that provides high-speed Internet service to businesses in 11 markets using WiMax technology. The company has placed several antennas on skyscrapers in New York City so it can sell affordable high-speed connections to businesses throughout the city.

Wireless service providers rent space on top of tall skyscrapers, such as the Empire State Building, and then route the wireless traffic onto fiber that runs down the building into the ground and out to the Internet or across the telephone network.

Wireless radios and antennas are placed on a platform that is not accessible to the general public. To get to the platform, people must crawl through a window. Warning signs are placed all around the area that say, "Radio frequency fields at this point exceed FCC rules for human exposure."

This picture shows TowerStream radios that are stacked on top of each other on a pole. Using the radios seen here in the photo, TowerStream provides a point-to-point wireless connection using WiMax technology to rooftops of its business clients. The service is a replacement for dedicated T1 lines, DSL, or cable modem service that businesses purchase for high-speed Internet access. When setting up a wireless link for the first time, technicians must carefully tweak the direction of the antenna so that it points to another antenna on the other side of the connection to receive the signal.

TowerStream's antennas sit on a platform that is 1,000 feet above the streets of Manhattan. It is just below the observation deck where the public can get panoramic views of the city. This is also the tier of the Empire State Building where the flood lights sit that are used to illuminate the top of the Empire State Building at night. Different color filters are used for different occasions. In addition to a regular schedule of colors, colors of New York's sports teams are often used on the nights they have home games.

Real estate on skyscrapers, such as the Empire State Building, is difficult to get, and it's expensive. TowerStream spent two years negotiating its contract with the building and finally installed its gear in 2004. CEO Jeff Thompson wouldn't say how much the company pays to rent the space. But he said there were enough zeros in the number to make him queasy.

Cellular phone providers, TV broadcasters, and other companies transmitting wireless signals also have radios on the building. Cell phone operators typically place their radios much lower--around 125 feet to 200 feet. The lower the radio, the more capacity it can deliver to their individual cell sites, Thompson explained. TowerStream's radios are placed at 1,000 feet to ensure the company can reach every rooftop in New York City. Major TV broadcasters, which also transmit over long distances, are also on this level. This picture shows some of their equipment, which transmits TV signals in high definition.

TowerStream CEO Jeff Thompson said the company is exploring ways it can use its point-to-point WiMax wireless service to provide backhaul for service providers that might want to create Wi-Fi hot zones in densely populated cities like New York.

Thompson said that the point-to-point wireless technology has advanced so much over the past decade that today it's a true competitor to fiber connections. The benefit of wireless broadband is that it can be deployed at a much lower cost. In this photo, Thompson points toward Brooklyn, where TowerStream has set up a 200Mbps wireless link that was established between radios on the Citi Corp. building in Long Island City across the East River and a building in Brooklyn 14 miles away.

TowerStream uses a meshed architecture with radios on the tops of other buildings nearby to build its network. This means that the radio nodes work together as a single network to form a mesh or cloud that provides coverage for the entire city. TowerStream typically has 8 to 10 points of presence or radio clusters on rooftops in every major city where it places radios. It then has two or three places in each city where it connects the wireless network to a fiber link it leases from companies, such as Level 3.