It works with a TV tuner, so it's dependent on the channels broadcasting in your area. You can use TVFool[0] to see estimated channel strength in your specific location.

[0] http://tvfool.com/index.php?option=com_wrapper&Itemid=29

Go to https://www.plex.tv/features/live-tv-dvr/ and click on "View channels in your area"

They discuss TV tuner cards they support.

Suggests this is means local over air TV. So whatever you get by just plugging antenna into your TV directly.

You get whatever channels you have now.

It works with a tuner or antenna