DVR in Plex or other app supported?

[Dennis_H]

I am getting a TerraMaster F2-221 for home use and to mostly stream MP4/MKV and FLAC files to my devices. So far those consist of Firesticks and RPI3 with DACs. I would also like to be able to use this as an Over The Air DVR. I would probably have to use PLEX, but am open. Anyone connect a Tuner to this box and have it work as a PVR? I haven't done this yet and am hoping to have some pointers on what tuner will work, and if there is enough power to do this.
Any other ideas?