Sources of error in U-Adcock high-frequency direction-finding

It is well known that errors in high-frequency direction-finding using U-Adcock systems arise from a number of independent causes. Experiments have been carried out to assess their relative importance, and statistical methods have been used to calculate the respective contributions to the total variance of error in a series of typical check bearings on known transmitters. The variance component, normally attributed to wave-interference errors, has been studied particularly, and the contributions from observational error and the effect of ground resistivity variations over the d.f. site have been estimated.