For masts near a half-wavelength high (180 electrical degrees) the mast has a voltage maximum (antinode) near its base, which results in strong electric fields in the earth above the ground wires near the mast where the displacement current enters the ground. This can cause significant dielectric power losses in the earth. To reduce this loss these antennas often use a conductive copper ground screen around the mast connected to the buried ground wires, either laying on the ground or elevated a few feet, to shield the ground from the electric field. Another solution is to increase the number of ground wires near the mast and bury them very shallowly in a surface layer of asphalt pavement, which has low dielectric losses.