RCA 32'' TV .....Good Picture but No Sound

Question

I have DISH Network satelite tv service. TV is located in the master bedroom. The problem is when I connect a coaxial cable to the antenna input and turn on the DISH unit, I get a good picture but static hissing sound. I cannot hear the program's sound at all. I even tried the DVD player through the same connection and get the same results. So what I do to get some use out of a ''good'' tv (while watching a DVD movie) is goto the audio menu and set the tv to ''external speakers with fixed output mode'' and send the signal through my receiver. This works just fine but I cannot watch DISH satelite on this tv because of the static noise. I have have the service technicians here at the house on three separate occasions with no solutions. I had DIRECTV before DISH and the tv worked just fine. The veiwing channel was 3, as opposed to 60 for DISH. Please help if you can!kenrama