The antenna should go to the back of the tv and not involve the hdmi cables. So yes , it’s probably in the antenna connections somewhere . You say the antenna meter( which I think is the power inserter) shows a signal so I’ll assume the amplifier for the jack antenna is on. Remove and check connections and also settings on any signal distribution box ( box of many buttons (BOMB) . Wire temporary cable from the power inserter or meter , the last known source of a good signal, to the tv. If that works the problem is in the cable between.