I want to get rid of cable and put a Roku Express+ on my old Sony. However, there are times when I don't want to stream, just view OTA. So beside the Roku, would I also have to attach a converter box & antenna? And would I have to change the input on the tv settings menu when I don't want to stream? Buying a new tv is not an option, so a clear, simple explanation to this 64 yr. old granny would be greatly appreciated!