local channels install

[shaun-ohio]

well i did discover one thing, about my install yesterday, that if i run a direct coax from the ota into an a/b switch, which along with the sat coax also, that i can watch the local channels, which the installer said i could not get, so i am using an a/b switch now, i get abc,cbs,nbc, along with 5 other pbs channels, still cant pick up pax which is only 5 miles from here or wb or fox, i brought the diplexer inside and hooked up both coaxes to it and all i could get was the sat signal no ota channels, so perhaps the diplexer is bad or what?