I can't remember the exact distances, but if the GV is stationary, it's something like 1.5K, if it's moving, I think it's 3K, and if parked under a tree, it's quite hard to see as the tree blocks some of the icon. These numbers change in a Storch. When in them, you can see GV's icons further away.
I do not know if this is changeable or not, maybe. I know plane icons can be adjusted with a setting.