Hi just had a guy over to talk about adding solar PV arrary to our residence. Big company been around for a while but all he had was a compas and if I want to do an indepth study of the site I have to sign on the dotted line! I remember seeing somewhere that there is a simple device that will let you know if there is a problem with shading from surround trees and or buildings. Any body remember what it is called or a web site that talks about it? I could swear I saw someone's ad that would rent it out by the day for some fixed fee. Just can't seem to find it today.