Why does Earth have two stargates?
I think this was covered in the series, but when I tried to find it in the Stargate wiki, I couldn't find it.
Why is it that incoming wormholes seem to always connect with the SGC stargate? Why don't SGC teams ever end up connecting to the Russian gate when they dial home? Since they're dialing coordinates and not a specific gate, how do they distinguish between one gate and the other?