In the same week that NBCUniversal placed a big bet on ad-supported streaming, top local TV station owner Sinclair Broadcast Group has launched its long-gestating service Stirr.

The free, ad-supported offering inlcudes local, location-based content as well as 20 national networks, including Cheddar (finance), Buzzr (game shows), Stadium (sports) and CONtv (Comic-Con) and the family-friendly Dove Channel. STIRR is launching on iOS and Android devices, Amazon FireTV, Apple TV, Roku and via its website.

Stirr has also developed original channel for movies, sports, lifestyle and city content. The streaming service plans to add new linear networks each month, growing to more than 50 by the end of this year.

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Local channel Stirr City offers 24/7 programming tailored to where a viewer lives. Its content mix will include live local news, local and regional sports, entertainment and city-focused lifestyle programming, all of it generated by the local Sinclair station.

For several years, local TV stations have been buffeted by massive viewing shifts and cord-cutting, with a host of industry and technological hurdles standing in the way of full over-the-top streaming of local signals. Sinclair and other station groups have long agitated for regulations established in the 20th Century to be eased, giving broadcasters a fair chance to compete with tech rivals.

“We are entering a new era of broadcast television and our number one priority at Sinclair is to help advance the industry and increase access to broadcast content in the midst of a digital age,” said Sinclair CEO Christopher Ripley. “With the launch of STIRR, we intend to offer audiences an easy, convenient and free way to watch live local and national channels, as well as access a deep selection of on-demand programming.”

Sinclair has steadily acquired station assets to emerge this decade as the largest station owner in America. It also has national properties such as the Tennis Channel and digital assets such as the streaming news channel Circa. The company is also seen as a top bidder for Fox’s regional sports networks, which Disney must divest as a condition of regulators’ OK of its Fox deal.

Nexstar’s pending deal to acquire Tribune Media would make it the No. 1 local TV station owner, if regulators approve the merger. Sinclair’s deal to acquire Tribune was rebuffed by the FCC last summer, more than a year after it was initially proposed.