hi, i'm going to be building a HTPC with a avertv pci tv tuner which has an atsc tuner and an ntsc tuner, both coax, a s-video port, and is clearQAM capable. Now i seem to understand if i get comcast basic cable for this, i will get normal analog channels and local hd channels no problem. My question is, if i get comcast digital cable, do i need a STB to decode the digital cable channels (either HD or non-HD), or will the ATSC tuner already do this? Lastly, i've read that i couldn't do hd channels (local or encrypted) over coax, so how is it possible that these cards and tvs with just coax in can get local hd? is it just dumbed down to SD quality over the coax? Any help is appreciated.