Some Experiments on Night Errors for Long Waves

This paper describes the results of experiments on night errors observed for a 19.7-kc station located at a distance of 148 km, and compares them with the results of theoretical analysis. Cyclic variations of bearings, mostly two, are noticed at sunset and the same at sunrise in inverse way, the maximum shifts being about 30 deg. At the moments when the maximum shifts occur, the bearings are distinctly observed, while they are broad at others. From observations using a horizontal loop and a unidirectional antenna, polarization angles and intensities of space waves are found after Eckersley´s process, assuming or empirically determining phase differences between surface and space waves, incident angles of space waves, and intensities of reflected waves on the ground. It is pointed out that the observed and theoretical values of bearings and their broadnesses are in good agreement.