The "TV" input is for the internal TV tuner.
You are using an external tuner, so you have to use one of the HDMI inputs. I believe the only other way to do it is if your tuner has a RF out to connect to the Antenna input of the TV.
You also have the option of renaming the HDMI input.
I have a HDMI cable from my HD Receiver to the TV (Samsung 55" TV Model: LN55B650T1FXZC s/n: AYQC3CNS400159X Version CN01) but in the Media list, if I select "TV" it shows only snow. I have to go down to HDMI1/DV1 to make the TV show. There are FOUR HDMI plugins on the back; 3 together and one on the "side." None of the 4 allows TV viewing with "TV" as the Source.
How can I make Source "TV" show the TV?