Première analyse des mesures de propagation oblique effectuées à Gometz-La-Ville sur le signal du satellite SIRIO 1

This paper discusses the results of measurements on the emissions of the Italian satellitesirio 1, carried out at the Gometz-la-Ville earth station during a one year period in order to assess the quality of future Earth-satellite links at frequencies above 10 GHz. The contributions of rain and snow to the measured attenuation are determined. The results are compared with those obtained by theccir prediction method. The attenuation due to a wet plane radome is evaluated. The variations of polarization decoupling as a function of attenuation are compared with those predicted by theoretical models and a method for determining the quality of the liaison when the same frequency is used on two orthogonal polarizations is proposed.     

Sur les méthodes de calcul de l’exposant linéique de propagation et d’impédance caractéristique des câbles aériens et enterrés

The propagation constant of a line or a cable, and its characteristic impedance represent two parameters which are needed in order to calculate the variation as a function of the time of a current induced by an emp.For the aerial lines expressions which take into account the presence of the soil could be developed but the case of the buried conductors is of a more difficult approach. The aim of this study is to present solutions introduced by different authors and to compare them with a calculation method for the propagation constant using iterations, proposed by the authors. If this value is known it is shown that the characteristic impedance calculation of buried cables can be improved by avoiding the necessity to compute with a reasonable precision the impedance of the ground.