The balloon-borne, vertical-wire antenna system used for measurement of the atmospheric conduction current above the boundary layer of the earth was introduced by Kasemir (1960) and has been utilized by several investigators to measure globally representative values of the air-earth current. The values of the atmospheric conduction current density measured by this technology and presented in the literature (~2 pA/m2) ought to be multiplied by a factor of 2 to correct for physical processes at the antenna boundary. An analysis of the interaction of the balloon-borne, vertical-wire antenna with the atmospheric electrical environment shows that this technology can be employed to produce reliable measurements of the atmospheric conduction current; however, some of the reported measurements exhibit a possible deviation in performance, some of which can be explained by our analysis. The solution for the conducting spheroid is further developed in the appendix to obtain additional results. Analytical solutions are found for the electric field, conductor charging, and current measurements when the polar conductivities are unequal. Electric field enhancement factors for spheroids and approximate solutions for spheroids and other elongated objects are given. The distribution of induced charge along the axis of spheroids is shown to be linear and the solution indicates a similar induced charge distribution along all long conductors. The theory indicates that the 45¿ cone of protection rule probably overestimates the area protected by tall conductors.