Towerstream Wednesday announced that its first network using WiMAX technology is operational in the Windy City. Instead of choosing a new market to deploy the new technology, Towerstream has opted to launch in one of its established markets using Alvarion non-line-of-sight gear to augment its existing network point-to-point and point-to-multipoint networks.

Towerstream is a metropolitan wireless ISP, selling T-1 and fiber equivalents to businesses over broadband wireless links delivered from the tops of skyscrapers. Until now, Towerstream has used proprietary point-to-multipoint gear in the 5.8 GHz unlicensed bands, but such connections depended on direct line of sight between customer and base station. That limited the carrier’s footprint in markets such as Chicago, where other tall buildings could block Towerstream’s signal.

After the FCC started allowing operators to use the 3.65 GHz frequencies, Towerstream began experimenting with WiMAX equipment tuned to the new frequencies. Towerstream CEO Jeff Thompson said the equipment has two major advantages over the current proprietary gear it uses: It can bend around buildings due to smart antenna technologies, and it fits neatly into the global WiMAX ecosystem, allowing Towerstream to leverage the scale of hundreds of worldwide WiMAX deployments to procure cheap equipment.

Alvarion’s BreezeMAX 3650 kit is technically the same base station it uses in its 2.5 GHz and 3.5 GHz deployments, but because it is tuned to a non-standard frequency, it officially won’t qualify as WiMAX technology. The WiMAX Forum has no plans to certify the band, as it is entirely unique the U.S., but Forum officials said 3.65 GHz operators will still be able to tap into the same equipment economies of scale as “certified” operators because the infrastructure is identical. What they won’t be able to take advantage of is WiMAX’s embedded-device ambitions, as the 3.65 GHz market isn’t big enough to justify large numbers of consumer electronics. Towerstream, however, is indifferent to that market, as it plans to use the equipment solely for access, which requires only easy-to-manufacture gateway modems.

Alvarion was a busy vendor this week and last, announcing two other new contracts in the 3.65 GHz market. It is supplying both 2.5 GHz and 3.65 GHz gear to Wisper Wireless, a WISP with a footprint of 550,000 in western Minnesota. Last week, Alvarion announced a deal with Azulstar to deploy its 3.65 GHz equipment in western Michigan and New Mexico.