As per the OP. It is an old Sony but HDTV Ready, meaning that is ready to process the HDTV higher resolution signals but it does not have an ATSC tuner otherwise it would be an HDTV TV set , instead of just a Ready one.

The FTA Satellite stores sell a Converter box for 55 cad that allows you to receive the new Digital signals (all from US are now Digital only) but it would only be in SD resolution since they are intended for the Old CRT Tv's. Those also have a passthrough capability that passes the analog signal to the TV , which in some cases is very handy and convenient.

For what you want , Samsung for instance makes ATSC standalone tuners that obviously send an HDTV signal via Component at least to the TV. But I have no idea where to buy thsoe locally.

BTW , As usual I almost forget, Welcome to the forum.