Some Observations of Short Period Radio Fading

The data presented are the product of an investigation started at the beginning of 1928 with the object of studying the short-period fading of radio broadcast transmissions. Particular attention was paid to those intensity changes which take place during periods ranging from a few seconds to several minutes. Various antenna combinations were used in making simultaneous records in order to separate the effects of various causes of fading. The data secured partly confirm the conclusions of previous investigations, partly point to other sources of fading. Varying intensity of the indirect ray and interference between indirect and ground rays are evidenced as in earlier experiments, but rotation of the plane of polarization of the indirect ray is also shown to be a considerable factor and there are suggestions of lateral direction shifts of the indirect rays and of their arrival by multiple paths.