As @Strega said, only the TVs have a built in tuner. But there are network tuners that work with Roku devices. Silicon Dust sells some, and as he also mentioned the Tablo is another. I have a SD HDHomeRun Flex 4K on my network, and it gets both the existing ATSC 1.0 stations but also the new ATSC 3.0 stations that are currently being tested. In my area (near Seattle) I have ten different 3.0 stations online, although none are actually broadcasting anything in 4K yet. But if you want to watch the 4K stations, you need the Ultra 4800/4802, as it's the only one that supports AC-4 audio, which is the ATSC 3.0 standard audio codec.
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