I recently had a problem with noise on my new DCT 5100 Motorola HD decoder. I never had noise with my previous Non-HD decoder. I read a thread that said I should check my Coaxial Splitter and make sure that it was a 2Ghz capable. I had a 900Mhz installed. I switched them and that fixed the problem. Why did this fix the problem? Is HD and Digital Audio broadcast at higher frequencies?