Investigation of the Attenuation of Electromagnetic Waves and the Distances Reached by Radio Stations in the Wave Band from 200 to 2000 Meters

Abstract

The paper gives the results of a large number of field strength measurements in which the relative radiation characteristics of the transmitting and receiving stations remain constant even on changinig their distance. The constant of attenuation as a function of the wavelength was determined for the propagation of waves over land from these measurements. The method used eliminates the errors in the absolute determination of the received field strength. The attenuation values that were obtained were used for the calculation of the received field strengths as a function of wavelength and distance in two examples (long-wave Zeppelin and long-wave airplane station). We see that it is more important to use a long wave over land than over water. The best waves as regards propagation and radiation can be deduced from this work. The dependence of the internal efficiency of the antenna circuit and of disturbing reflections on the wavelength must be considered especially carefully. The results of the work make possible the numerical calculation of the range of radio waves over land in the wave band between 200 and 2000 meters. They should be more reliable than the rule-of-thumb methods hitherto used.