I am in Northern Ireland and for years I have been getting Freeview (channels 52-58) and Saorview (Irish Freeview channels 42-43). They come via separate aerials, a diplexer and distribution amp to three TVs. Recently the signal became unreliable and a contractor installed a new broadband diplexer to combine the two separate aerial feeds. One of the TVs worked fine but the other two stopped receiving Freeview and only received Saorview. The contractor checked the outputs from the distribution amp and they were fine. He then changed the Coax cable to one of the two TVs and it started receiving both Freeview and Saorview. Does anyone know why cable would carry one set of channels and not others?