jbntx wrote on Dec 14^th, 2010 at 8:13pm:

What are we supposed to be seeing through that "radar" anyway? Is that the ground or straight ahead? What use is it at 30,000ft

It is good when you fly at night in mountainous areas. But the only mountain the radar would really warn you about at that altitude is Mt. Everest (29,500ft) and K2 (27,000ft), mainly because it only measures things from a particular altitude down.  You can wee this as when you get lower, the terrain's 'peaks' will increase in size and brightness on the screen.