Spatial Variability of VHF FM Radio Signals with Surface Refractivity Values in Niger State, Nigeria

Abstract

Radio refractivity N exerts considerable influence on radio signals at Very High Frequency (VHF) and higher frequency bands. In particular, surface refractivity correlates positively with radio field strength, and knowledge of its temporal and/or spatial variability is important in predicting performance of terrestrial radio networks, especially at VHF frequencies. In this work, measurement of electric field strength of Frequency Modulated (FM) radio signals in Niger State, Nigeria was carried out at the onset and peak of the wet season; variation of surface radio refractivity was obtained in Minna, Niger State based on concurrent measurement of surface air temperature, pressure and relative humidity. Variation of electric field strength of FM radio signals in the wet season is found to agree in general with the observed variation of surface radio refractivity, N_s, in Niger State, Nigeria.

Keywords: Electric field strength, surface radio refractivity, propagation