Define "maintain". If you mean "pay the guy who installed it to keep it in good working order", there's no problem. But if you mean "pay the guy who installed it to record everything that comes off the antenna then set up a commercial service to redistribute that content anywhere in the world to a device of your choosing" then it's a probably illegal. On an individual basis it's also pretty inconsequential, so as a practical matter, it's not a concern.
But if you were the owner of a big enough building and were also charging people for the wire service to their apartments - and beyond - it gets more problematic. Indeed, a variation on this is what the Supreme Court ruled against decades ago. And if you do this on a truly industrial-sized basis (as Aero did) then expect the hammer to drop.
But if you were the owner of a big enough building and were also charging people for the wire service to their apartments - and beyond - it gets more problematic. Indeed, a variation on this is what the Supreme Court ruled against decades ago. And if you do this on a truly industrial-sized basis (as Aero did) then expect the hammer to drop.