Some notes on wireless methods of investigating the electrical structure of the upper atmosphere. I

Various direct wireless methods of measuring the "effective" height of the atmospheric ionized layer are discussed and compared. For a layer of horizontal stratification, and under conditions for which the influence of the earth's magnetic field may be neglected, the general equivalence of the quantities measured by the various methods is demonstrated. The effective height in such cases is shown to be greater than the maximum height reached by the atmospheric ray. Proposals for using these methods to obtain information concerning the gradient of ionization in the layer are put forward.