Radio Refractivity and the Effective Earth Radius Factor (k-factor)
For ease of geometrical analysis, these waves are represented as straight lines then compensation is done by assuming an imaginary earth radius, otherwise referred to as effective earth radius, [r.sub.e] .
where k is the effective earth radius factor and [r.sub.e] is the effective earth radius and [r.sub.o] is the true earth radius and [dn/dh] is the refractive index gradient.
If the choice of both the median and effective values of the effective earth radius factor for link design is not appropriate for the particular topographical setting, the signal may be obstructed by the Earth and consequently little or no signal is detected at the receiver.
Previous Work on the Effective Earth Radius Factor in Africa
From the distribution modeling results, we conclude that just as in [19,21,22], the distribution of the effective earth radius factor for South Africa is bell-shaped, centered almost symmetrically around a median value, [[mu].sub.k].
Baker, "Predicting the long-term average of the effective earth radius factor for South Africa using ground based observations," SAIEE Africa Research Journal, Vol.
Baker, "A novel semi-empirical model of the effective earth radius factor," IEEE Transactions on Broadcasting, Vol.
Ajewole, "Variation of radio refractivity and effective earth radius factor (k-factor) over Akure, South Western Nigeria," IEEE, 978-1-4244-5118-0/11, 2011.
Afullo, "Effective earth radius factor characterization for line-of-sight paths in Botswana," IEEE AFRICON Proceedings, 227-232, 2004.
Afullo, "Effective earth radius factor measurement and modeling for radio link design in Botswana," SAIEE Africa Research Journal, Vol.