I suggest checking your TV aerial cable connectors, they could be corroded from the weather.
That's a you thing. Worked fine for me when I still had a TV and gave me HD content which definitely was improved (if not necessarily new).
Strictly speaking it's a "my parents" thing. I've only streamed for a few years now.
I get the impression it's a bit of a postcode lottery i.e. if you're the wrong side of a hill etc.