Wireless networking startup Meraki plans to deliver free wireless Internet access, supported by advertising, across San Francisco by the end of the year, it announced Friday.

An earlier attempt by Google and EarthLink to offer free city-wide Wi-Fi access in San Francisco foundered in August when EarthLink pulled out. They had planned a two-tier service, with faster, paid access provided by EarthLink and a more limited, advertising-funded service to be offered by Google. The search engine giant is also an investor in Meraki.

Meraki will base the service on an existing project covering parts of the city, Free the Net, which has signed up 40,000 users over an area of 5 square kilometers since it began last March.

To avoid the need for extensive cabling, Meraki will build the backbone of the network using a mesh network of solar-powered wireless repeaters installed on rooftops. The nodes will use some of their wireless capacity to offer Internet access to those nearby, and the rest to haul traffic back, via adjacent nodes, to the network's core.

The company is looking for city residents willing to put a repeater on their roof. Those hosting a repeater will get free access to the service -- but so will their neighbors -- although for them, the signal may not be as strong. Although devices are shared, Meraki aims to deliver data rates of around 1M bps (bits per second) to each user.

Meraki will pay the cost of rolling out the service, and no public funds are involved, it said. Investors have offered the company an additional US$20 million in venture capital to fund the move, it announced Friday.

Ozone in Paris offers a similar wireless Internet service based on a network of wireless repeaters. Its service is only free for those who host repeaters, though: others must pay €18 (US$26) a month.