I was curious to find out how big the XM Radio constellation is because I was so impressed with our reception on our Thanksgiving trip to the mountains. On our way back from the cabin we rented, we took some roads that were in between mountains and deep in the trees and we never lost reception.
Well, the XM Radio wikipedia entry has lots of great info, but it wasn't immediately obvious how big their constellation is or current orbits. While searching around, I bumped into the decode systems page which led me to VITA.
I know nothing about VITA - perhaps they are scum; however, the interesting bit to me is that there is a group of volunteers that have a license for a satellite constellation. Interesting. Serendipity do day.