Abstract:
For proper radio link design and for any location where propagation is intended, a accurate
prediction of the distribution of effective earth radius factor (k-factor) is required. Traditionally,
a median value of 4/3 is assumed for communication design purposes, but in reality the true kfactor
values differ for different locations globally. In this study, the mean diurnal, seasonal and
annual variation of effective earth radius factor (k-factor) are investigated over Akure, South
Western Nigeria, for a period of five years, January 2007 to December 2011. Data from the ongoing
measurement of some meteorological parameters of the troposphere at the location were
used for the study. The measurements were carried out using facilities of the
Communication/Atmospheric Physics Research Group of the Department of Physics, the Federal
University of Technology, Akure. The results indicate that the diurnal variation of k - factor over
Akure during rainy season is majorly as a result of the contribution of the dry term of the
refractivity, while the diurnal variation of k – factor in the dry season showed strong dependence
on the wet term of the refractivity. k-factor values were generally high during the rainy season
compared to dry season where k-factor values were lower.The median value of k-factor for the
five calendar years in the height range (50, 100, 150 and 200) m are: 1.49, 1.46, 1.50 and 1.47
respectively, and the propagation condition in this geographical zone is mostly super refractive
