This is my report.
Also, this is the outdoor antenna I am using:
https://www.amazon.com/RCA-Compact-O...rca+tv+antenna
The condition of the antenna is great. It's only been up on the roof for about 2 months and shows no sign of wear or breakage.
I don't believe trees and buildings are a factor. There are many other channels coming from the same place (Empire State Building) that have no issues. Also, if a tree or building was in the way I would have a constant reception problem, not a problem that comes and goes.