On that map, that's probably one of the best spots for a human base, you get those telsa generators up and you've got yourself an awesome base. I've never lost as a human while playing that map with the base there. You can't see it, but there's a turret in the far right corner that takes on any aliens below who are trying to launch projectiles at the base.
And for everyone interested in this game, you should check out
Natural Selection too, its half-life, so you gotta pay for that. Personally I like Tremulous better though, Natural Selection uses the Half-Life engine...which is Quake 2 based, Tremulous uses the Quake 3 engine. Another reason I like Tremulous better is the whole "opensource" and "freeware" thing.
IRC is: #tremulous on irc.quakenet.org