A new filing with the Federal Communications Commission reveals how seriously Google is focusing on its plans for a wireless version of Fiber, its high-speed internet service.

The company has been testing a new wireless-transmission technology using the 3.5-GHz band in Kansas City, but the heavily redacted FCC filing suggests that it wants to dramatically expand to testing "experimental transmitters" at up to 24 US locations, including Provo, Utah, Omaha, Nebraska, and Boulder, Colorado, for a period of 24 months.

Google is requesting authorization to operate between the 3.4 and 3.8 GHz band.

"We are working to test the viability of a wireless network that relies on newly available spectrum," a spokesperson tells Business Insider. "The project is in early stages today, but we hope this technology can one day help deliver more abundant Internet access to consumers."

Google Fiber's original plan to spread super-fast internet across the US involved running high-bandwidth fiber-optic cable directly to each home that its network would serve. That process has so far proved to be expensive and slow-moving.

Since it announced the acquisition of point-to-point wireless-internet company Webpass earlier this summer, the Fiber team has started turning more of its attention to a using a new approach that will pair existing fiber with its own wireless technology.

The company has even delayed its Fiber rollout plans in two Silicon Valley cities as it looks for cheaper, wireless alternatives, according to the San Jose Mercury News.

Although several of the cities that Google wants to test are already Fiber cities, the tests will be non-commercial for now. All of the end-user devices used for testing will be in the hands of Google employees, contractors, and "'trusted testers' selected by Google on a volunteer basis without payment."