I just got an HDTV (sony KDL55HX800) and upgraded Brighthouse cable service to HD with cable box. I have the box connected to the TV via an HDMI cable and it looks great with tons of HD channels. However, a direct coax connection to the TV provides additional channels that are not available thru the cable box. I'd like to split the coax line so that I can connect to each separately so that I can switch between the 2 inputs on the TV. Unfortunately, the split isn't working. When on the splitter, the TV cannot find all the same channels that it can find when connected directly. Any ideas?