I'm using the automotive magnetic roof mount antenna in the window of my apartment. It's not stuck to anything, it's just sort of leaning against a book, angled out the window. It does work, on and off. I can be listening for awhile and then it will loose the signal and most of the time a little moving around of the antenna will bring the signal back. My questions are why can the signal be good for an hour straight, then all of a sudden gone? Would the Sirius indoor antenna improve the signal staying locked in and why? Is there something built inside the indoor antenna that would make it work better than the magnetic auto rooftop antenna? This is a Sportster 4 radio. Thank you.