4G Signal Dies in Walmart Stores
You walk into the Walmart store and your wireless 4G device comes to almost a screeching halt. This is not uncommon inside the newer Walmart buildings. It is caused by the corrugated metal roofs they use. If you stand back in a corner and look up inside the store, it is nothing more than a warehouse that fills the visual field of the human eye with decorations to give the illusion of a real department store, when in essence, it is nothing more than a warehouse building. The metal roof acts the same as a faraday cage, which the shorter the wavelength, the more shielded the signal is.