Aereo, a service that streams local broadcast networks to mobile devices, is broadening the range of its fight against content providers. A week after filing a countersuit against ABC, NBC, CBS, and other channels that had sued it for copyright infringement, the company has filed a second lawsuit — this one against PBS, Fox, Univision Communications, and local channels WPIX and WNET. As in the previous suit, Aereo is seeking a declaration that its service is not infringing copyright. This action was widely expected, and means that Aereo has now countersued all the major plaintiffs in the original suit.

Shortly before Aereo was supposed to launch, a number of local networks backed by the National Association of Broadcasters sued the company, claiming that by collecting over-the-air signals and rebroadcasting them with tiny antennas, Aereo far exceeded the scope of normal public broadcast laws. For its part, Aereo seems confident — almost aggressive — and hasn't let its legal trouble delay the March 14th launch: it's currently operating by invitation only in the New York metropolitan area.