Comcast unveiled nearly 200 Wi-Fi hot spots in Sonoma County on Thursday, surprising some city officials who said they were unaware the company had been building a network that gives its customers free access to the Internet away from their homes.

Comcast said it intends to continue expanding the network, which already lines much of the Bay Area and extends into several cities in the Central Valley.

"The goal is not to build a network that covers every square inch. The goal is to extend the Internet experience of the home to the outside world," Comcast spokesman Bryan Byrd said.

The service is provided by small antennas and routers inside businesses and on outside poles where Comcast already has equipment, which usually fall outside any ordinances of local jurisdictions.

The hot spots cover much of north central Santa Rosa and smaller sections of seven other cities in Sonoma County, according to a map published on Comcast's website.

The network includes a dozen hot spots in Sebastopol, where citizens concerned about the health effects of radiation from wireless radio devices fought previous Wi-Fi proposals and PG&E's introduction of SmartMeters.

Officials with the EMF Safety Network, which was founded in Sebastopol, did not immediately return telephone calls and emails seeking comment Thursday.

Four years ago, Sebastopol blocked local Internet service provider Sonic.net from installing Wi-Fi hot spots in town over emissions concerns.

Comcast did not contact most cities in advance, including Sebastopol, because the hot spots are regulated only by Comcast's statewide franchise agreement, Byrd said. The radio waves fall within emission standards established by the Federal Communications Commission, he said.

Sebastopol officials were surprised to learn of the rollout.

"It is possible some members in our community would have concerns about Wi-Fi, given recent history," said Mayor Guy Wilson. "I will accept as true what Comcast says relative to their legal right to do these technological installations. If Comcast does not have the right to do that, somebody will speak up."

The range of the signal is about 200 yards and the quality of the reception depends on such physical barriers as walls.

Wi-Fi networks allow customers with smartphones and tablets to connect to the Internet without using up limited minutes or data on a cellphone plan, Byrd said.

Comcast Internet customers will have free access to the Wi-Fi hot spots. Non-customers can get access to one free session and then pay for subsequent service. The cost is $2.95 an hour, $7.95 a day or $19.95 a week.

To view a map of local Wi-Fi hot spots, visit www.xfinity.com/wifi and go to "Find a Hot Spot."

"This is not a ubiquitous network that covers every edge of the city," Byrd said.

"We are not done. We are continuing to add hot spots every week. That network will continue to grow."

So far, the number of Comcast hot spots include Santa Rosa, 90; Sebastopol, 12; Windsor, 30; Healdsburg, 7; Rohnert Park, 5; Cotati, 6; Petaluma, 10; Sonoma, 20; Glen Ellen, 1; Kenwood, 2; Graton, 1; Forestville, 1; Bodega Bay, 4; and Guerneville, 1.

Comcast has 2.2 million TV and Internet customers in Northern California, Byrd said.

You can reach Staff Writer Bob Norberg at 521-5206 or bob.norberg@pressdemocrat.com.