A Note on the Theory of Night Errors in Adcock Direction-Finding Systems

The paper deals with the theory of night errors (i.e. those errors which cannot be estimated owing to their variation from minute to minute and their dependence on factors not easily determined) in wireless direction-finding systems, and has arisen out of experimental work carried out at H.M. Signal School, Portsmouth. Expressions are described for the errors which may be obtained as a result of the presence of both ground and atmospheric waves. The fixed Adcock system is shown to be less liable to error than loop systems, but there are substantial zones in which, for certain conditions of the atmospheric or indirect ray from transmitter, the fixed Adcock system is subject to blurred minima and to errors of bearing. These zones increase with increase of spacing between the aerials, and the maximum error occurs when the intensities of the ground and atmospheric waves are approximately equal. The rotating Adcock system, however, is shown to be free from blurred minima and errors due to night effect.