I know this is an old thread at this point, but still referenced I'm sure. I just wanted to throw in my two cents that in an indoor environment where humidity doesn't get out of control, kiln-dried wood, especially laminated plywood, is essentially identical to a plastic. The moisture content is negligible and the wood is electromagnetically inert. That's why antennae work from the inside of wood-framed houses with wood sheathing. The same wouldn't hold true for either outdoor environments or indoor environments that suffer high humidity, where the porous wood might absorb moisture and become an electrolytic medium. For my ideal antenna paradigm, which is to embed it within a wood-framed wall and thus eliminate any outward appearance of it, wood is an ideal building material. But for an even further, probably superfluous, measure to prevent interference, I've used nylon bolts and rubber washers to completely insulate the antenna connections from the wooden substrate.