Refractivity variations and propagation at Ultra High Frequency

Abstract

Present framework is established to deal with the refractivity variations normally affected the radio waves propagation at different frequencies, ranges and different environments. To deal such kind of effects, many researchers proposed several methodologies. One method is to use the parameters from meteorology to investigate these effects of variations in refractivity on propagation. These variations are region specific and we have selected a region of one kilometer height over the English Channel. We have constructed different modified refractivity profiles based on the local meteorological data. We have recorded more than 48 million received signal strength from a communication links of 50 km operating at 2015 MHz in the Ultra High Frequency band giving path loss between transmitting and receiving stations of the experimental setup. We have used parabolic wave equation method to simulate an hourly value of signal strength and compared the obtained simulated loss to the experimental loss. The analysis is made to compute refractivity distribution of standard (STD) and ITU (International Telecommunication Union) refractivity profiles for various evaporation ducts. It is found that a standard refractivity profile is better than the ITU refractivity profiles for the region at 2015 MHz. Further, it is inferred from the analysis of results that 10 m evaporation duct height is the dominant among all evaporation duct heights considered in the research. Keywords: Refractive index, Refractivity, Parabolic wave equation, Propagation, UHF, Antennas