They have a radar to refer to. They are not radar controllers. Pretty
much any class D near a larger class C or B airport will have a scope in
the cab. Get away from a larger radar facility and there's no radar for
that smaller airport to have in the first place. And some airports
bought their own radar and had it added to the system. That's happened
here in Montana.

An aside: Lake Lawn Lodge (in Wisconsin) actually had their own radar
on the roof of their FBO. It looked like a boat radar (and I never
saw it in operation -- by the time I started flying in there, they
were on their way out of business), and I don't know what they could
actually SEE with it -- but it's the only uncontrolled field I've ever
seen with radar!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"