In what insiders say is the beginning of a new holy war between Fox and Nielsen, the Fox Television Stations group Wednesday announced a long-term deal with Nielsen rival Rentrak that is the first to cover local TV ratings for an entire network-owned TV station group. It’s not the first time a major TV network has agreed to license Rentrak’s ratings -- in March, CBS announced a deal with Rentrak that included local TV ratings for four of its local station markets -- but this is the first to cover all the local markets it operates in. The Fox deal affects 28 owned stations operating in 18 local TV markets from New York City to Ocala-Gainesville, Fla. The agreement provides Fox with access to Rentrak's StationView Essentials software and TV ratings information including Rentrak's single-source auto and political ratings. An executive familiar with the deal said it’s not simply a hedge to develop an alternative source for TV ratings, but is part of a bigger fallout with Nielsen over its contract, and also relates to Nielsen’s push to introduce a controversial new “hybrid” method of measuring local TV audiences that has had many local broadcasters up in arms. An aggressive position by the National Association of Broadcasters in February convinced Nielsen to delay a rollout of the method, which would add “broadband-only homes” into its local TV measurement samples, effectively reducing the number of “traditional” TV households, which many local broadcasters believe could negatively impact their ratings “currency,” leading to lower advertising rates and revenues.