trex88i

Newbie here also and starting to design an extensive system for the house, so I came to this forum to review options and similar setups I'm looking to try and implement. I was planning on either doing HDMI out from the box to either a Coax distribution throughout the house to all TVs or possibly HDMI over wifi to 1 or 2 main TVs. I'm a career Network Admin for 20+ years and I understand most network technology, but haven't dabbled much in TV signaling, but my question would be, why couldn't you use a HDMI to Coax modulator or HDMI to DVB-T modulator for this distribution?