I have Sirius XM radio in both of my cars. It works everywhere, except some overpasses and all tunnels. No matter the direction I am traveling. So my wife wanted to use it at home. I purchased a small unit with a cable and presumably, a patch antenna on a hinged box. The orientation and angle of the antenna are super critical, and even then, doesn't always work, with continuous dropouts. Is it just the antenna, or is the receiver just a piece of junk? If it is the antenna, how do I get or make one that works. I have the antenna outside, pointed to the South.