Extra channels- Olevia vs. Polaroid

I just bought an Olevia 37" 237T LCD tv, and after the initial scanning I saw a few channels that I have not seen before from my standard cable service (Time Warner). E.g. 85-3 and 120-12. They are local broadcast network channels like Fox & PBS etc. But they do look sharper than the regular 3 to 11 feed. And the display info show either 720p or 1080i. Could these be actually HD, even though I have not subscribed to HD, and is not using any cable box?
My 1-year old Polaroid FLM 3232 (32" LCD) cannot pick up any of these extra channels. What makes the difference? Looking at the specs, the only relevant difference is 1080i for the Olevia, an 720p for the Polaroid.
What part of the spec would tell me a TV can pick up those extra channels?

Most Olevias have a QUAM tuners. I can pick up 13 hi def channels on standard RCN cable in PA.

What you are seeing with the dashes are called sub channels and some cable companies have a lot of them.

I get about 50 more stations on my Olevia, then on my non QUAM tuner TV.