Oblique-incidence measurements of the heights at which ionospheric scattering of VHF radio waves occurs

Indirect measurements of the heights at which ionospheric scattering of VHF waves occurs, using the technique of measureing the differences in the times of arrival of tropospheric and ionospheric pulses received over an 810-km oblique-incidence path, were made by the National Bureau of Standards in November 1952 and in January 1953. These measurements show approximate heights of 86 km and 70 km, respectively, for the night-time hours and the midday hours. The accuracy of the heights obtained in this way are subject to uncertainties about the actual tropospheric delays.