Today I bought a used TiVo Series 3 HD. I plan on using this unit for OTA channels. Allow me to explain my situation. I currently have comcast internet only. However, the cable line that comes in for my internet, I've been using a splitter on it, one line goes to my modem and the other to my Vizio TV. My Vizio TV has a built-in digital tuner, and I have been getting OTA channels through the cable wire the entire time with no issues. So today, after I bought my TiVO S3 HD, I thought the mentioned above would work as well for the TiVo. I ran the set up and the channel guide for "antenna". No channels were found using the pre-existing cable I've been using that has been working for my Vizio TV. Now, the question is, do I actually have to use an antenna if I'm on antenna mode. I mean, the OTA channels are coming over the coaxial cable just fine for my Vizio TV. Please advise. Second question. My friend who work for comcast has just about every channel for free. He's willing to get me a cable card to use with my box. Obviously we don't live under the same roof, what are the likelihood that the cable card he gets for me will work with my box. I don't have a subscription and don't plan on getting one. Thank you everyone.