Performance Analysis of Microwave Radio Refractivity on Radio Field Strength and Radio Horizon Distance Over Akure, Nigeria

摘要

Surface radio refractivity studies are being carried out in Akure, (7.15°N, 5.12°E) South-Western Nigeria, by in-situ measurement of atmospheric pressure, temperature, and relative humidity using Wireless Weather Station (Integrated Sensor Suit, ISS). Five years of measurement (January, 2007-December, 2011) were used to compute the surface radio refractivity and its diurnal, daily, seasonal and yearly variations are analyzed. The results were then used to compute radio horizon distance. (R_(DH)) and examine the field strength (FSV) variability. Results obtained show that the surface radio refractivity, N_s, varies with the time of the day as well as the seasons of the year. High values of N_s were recorded in the morning and evening hours while the values were minima around 1,500 h local time. An average value of surface radio refractivity of 364.74 N-units was obtained for this location. The annual maximum mean of FSV is 15.24dB and the minimum is 2.20dB. This implies that the output of a receiving antenna in Akure may generally be subject to variations not less than 2 dB in a year, but can be as high as 15 dB.