I work as a systems engineeron next-generation weather satellites, so I know a little about satellite communications. Unlike XM which uses geosynchronous satellites, Sirius has three birds in a 'tundra orbit' which is highly elliptical and gives each satellite about 16 hours over the Northern Hemisphere each day. Therefore you should be able to receive the carrier from two birds at all times, although it is an S-ban,line-of-sight signal. There is a delay between the two carriers that your Sirius receiver decodes, which should give you a four-second buffer. Theoretically it should work a little better than XM in areas with obstructions (buildings, trees, mountains, etc). I am guessing that your trouble lies with the antenna. Try a different model antenna.

 

i am putting my vote in for xm, i have never had alot of time w/ sirus but i have nothing but god to say about xm. the only time it drops is when driving under a bridge or a tunnel. also has opie and anthony, those guys are great!