My problem was that in the living room of our house "only" an antenna signal from the satellite dish arrived on the roof and I could not thus use the full functionality of the TWIN-SAT receiver with hard disk recorder. The option, a second antenna cable from the roof through the entire house to move into the living room, turned out as my wife lodged their veto! ;-) Fortunately someone has invented this device, which I could connect without problems and put into operation so that I can now, for example, to record a program and watch another program, whether horizontal or vertical digital channels! The antenna cable from the roof to the living room with us about 30-35 meters long and the signal (even with HD channels) takes the Stacker De-Stacker without any quality loss to the receiver. Just buy it !!!!!