Dual-to-Single Sirius Satellite Antenna?

[MogulB]

I was wondering if anyone has come across this. I've been searching in vain for a reverse splitter that would allow me to hook up 2 Sirius Satellite Antennas (into 1 line) into my module. Right now, I have one antenna installed in my X5 spoiler. While the stealth factor is great, the signal quality seems a bit degraded ever since I re-located it from the rooftop into the spoiler. I live in SoCal and for me there quite a few 'dead' spots around town where the stereo goes into "Acquiring" mode . Well, I want to fix that! I was wondering if anyone has added a second antenna to their module with success. I would, of course, install the second antenna into the spoiler too with the hopes of a decrease in dropouts and increase in signal capture strength. Any help would be appreciated Thanks!!!