I am using a dte-7100 receiver and it seems whenever I lock in H signals. I am unable to manually enter and tune vertical signals. For some reason it won't let me switch. I have it slaved VIA Openbox. Even when the channel on the openbox is on the desired polarity the digitrans will not tune in that polarity. I am not sure if there is a setting I need to switch but it is very inconvenient.