JB wrote:
there's nothing between the antenna and the sky
other than the roof decking and shingles. I don't expect them to add a
lot of attenuation, but I
could be wrong.

Maybe 3' makes a big difference. I have always seen a difference between
antennas in the attic or stretched out on the roof, and antennas even a few
feed above the roof. I don't know if it was shingles or what. It would
really be interesting to see what kind of shingles are transparent. I have
seen antenna farms hidden behind fake gables.

Well, there's nothing like ground truth, JB, so I'll defer to your
experience vs my conjecture. Possibilities for further RF attenuation
might be the materials in use. Those little rocks used for color and
grip. Fiberglass is used a lot for the base, but there may be other
fabrics too. It's a composite material, who knows, there might be carbon
in it as well.

- 73 de Mike N3LI -