Kab, I took a large section of nylon screening (black) that I had and laid it on the dish. It did not block the signal, WA Fl. I don't know if there would be a difference if it was a distance from the dish and not right on it. Then there's this post from 2008...
Just to give an update to this post..
The installer came out the other day and set up my dish inside my screened in porch. After he was done I ran through all my signal strengths and they all seem to be very strong. It doesn't look like the screen is blocking the signal to me, and if it is, its too small to detect IMO.
rkick you weren't joking about the temps and humidity, good grief!!!