Surface Radio Refractivity Variation over North-Western Nigeria

Abstract

Good knowledge of refractivity profile is essential for good planning of communication links, surface refractivity profile of a station is particularly required for enhanced planning and performance prediction of terrestrial radio links especially in tropical regions where ITU-R has called for such local propagation data. the monthly and seasonal variability of surface radio refractivity over North-western Nigeria was investigated for a period of five years (2008-2010). the monthly mean surface radio refractiivity (Ns) was recorded in dry season and 368 N-units in wet season. Average value of about 328 n-units is observed with annual range of 80 N-units in the n0rth-western Nigeria. The result of the investigationalso showed that relative humidity and temperature have major influence on the variation of surface radio refractivity while pressure has relatively less influence on Ns variability. The surface refractivity profile shows that for a transmitter height of 200 metres radio horizon distance is between 60.5 km in wet season and 58.4 km in dry season in North-western, Nigeria. Therefore, terrestrial radio communication links must be planned in line with the findings of this research work for best performance in the north-western Nigeria