Roy Lewallen wrote:
wrote:
. . .there is foil on the back of my attic roofing. . .
I want to operate most VHF but I like 20 CW and 10 FM and 6 meters -
440 mhz both SSB and FM. So I've been trying to come up with an antenna
to cover that. I have the antennas pretty much decided but Bingo -- the
roofing material problem pops up and I don't have any idea how much
signal I will lose through that stuff. If it is a few DB and messes the
pattern up a little I don't care, but if it is 20 db and won't tune I
do care. . .
Does anyone have any experience with this kind of attic. I have heard
everything from it wont work to people that said it worked better than
in other standard plywood attics.
The whole range of reports could be completely true. There are many
variables involved, including but not limited to the width of the batts,
whether and how much they overlap or how far they're spaced, how far and
how they're oriented relative to the antenna, the type of antenna, the
frequency, possibly the thickness of the aluminum, and the directions
and elevation angles of desired communication.
Hi Roy,
This may be known only to people who live where the sun actually appears
in the sky on regular occasions. What Frank is talking about is not
ordinary foil-backed insulation batts. It is now very common in the
South for the plywood sheeting used in roof structures to be completely
covered with a bonded aluminum foil which serves as a radiant barrier.
The only gaps are the small cracks between the plywood sheets. It is not
the same as a completely solid sheet of aluminum, but the continuous
aluminum pieces are much larger, and the gaps are much smaller than
those that would be found in a typical installation of foil-backed
insulation.
Your answer of "it depends" is of course completely correct.
73,
Gene
W4SZ