Before purchasing any equipment, I want to be certain I will be able to get to at least some satallites because I live in a village full of large trees. I have made an angle finder from a couple of paint stirring sticks and a protractor. I cannot see the horizon, but from a south facing second floor window, if I keep the lower leg of the finder level, would the angle between the legs be valid for finding a satellite?

Eg - elevation of AMC3 is 39.9d. If the line of sight angle from dish to the top of a tree equals or exceeds this angle, I should be able to receive a signal, correct?

Also, in determining the angle, how much space should be allowed over the top of an object as a margin for errror?

Thanks for any help.