Hollywood has been fighting tooth and nail precisely to prevent you from doing this. If your TV does not have an OTA tuner, there are a few digital OTA tuners for sale, mostly from China (they look like set top boxes). None have really stellar reviews. Something like this:
A more generic solution would be something like a HDHomeRun, which converts OTA signals to an MPEG2 or h.264 stream sent over your network. Then any device which can decode those streams can "tune in" to those channels. Unfortunately, the software side is usually lacking (unless you have a media server like Kodi). Windows Media Center used to be the simplest/most reliable way to get this to work, but Microsoft got rid of it with Windows 8 (probably under pressure from Hollywood - they do not want you to be able to manipulate digital streams like this, they want you to watch when they say you can watch, or buy the blu-ray).