If I use Plex DVR and live streaming with a digital tuner and antenna, can I get channels like AMC and FX?
An antenna means over the air broadcasts (OTA) - and unless AMC and FX are being broadcast over the air then you won’t get them.
I believe both of the channels you list are cable channels and likely won’t be available OTA. For a listing of what channels are available in your area, check out http://www.antennaweb.org/ This will also tell you how far away the towers are and what antenna type is recommended.
