We may be able to get away with nails because we are not going above 1Ghz. At that frequency one quarter wavelength is about 3 inches. Go much above that frequency and 2 inch nails start looking like a short, which would reflect and mess up the readings.
Bill Franklin [email protected] > Nails versus dielectric fasteners has been debated for years now and I don't > think anyone has come up with a definitive rule. I know of two facilities > that > use nails for their shelters without ill effects (there are probably more); > other folks prefer all-dielectric material. Whether you can get away with > metal fasteners probably depends on how many you have, and how long they are > compared with the shortest wavelength you need to measure. In other words, > what do they really DO to the RF field you need to keep undisturbed? THAT is > the thing to watch out for. > > My opinion, natch, and not my employers'. > > Cortland > > > We built a 3 Meter site a few years back - maybe some of our > experiences will help. We built it using all wood framing with nails > no bigger than 16 penny (about 2" to 2 1/4"). We have two windows > with plastic frames (to let in some light), a ridge vent that is made of > cardboard (for ventilation), and a ridge pole that is made of plywood. > The outer surface is plastic house siding. We used asphalt roof shingles. >
