Connecting outdoor HD antenna?

In Tivo Series 3 HD DVR what is the effect on connecting both antenna and Cable coming from the wall?

• because antenna connection is optional to add, so if I connect both of them at the back of HD DVR what will happen? is there specific program that will be added?

• Answer:

  This double input is what gives the tivo the ability to record and watch two channels at once. If you hook up the antenna you'll only get the local HD channels. If this is your only source of HD, then that's a good choice. I split my cable before the HD cable box and 1. Run the plain cable split into one input and then 2. run the outlet of the HD box into the other input. This works real well for me.