UHF Wave Propagation Losses Beyond 40 Percent Fresnel Zone Radius in South-South, Nigeria

Wireless signal deterioration in major sub-urban locations has been cause of concern to stakeholders. This study, therefore, under-take empirical study of the characteristics and issues of electromagnetic wave propagation under line-of-sight (LOS) signal transmission in Akwa Ibom State. The intent is to determine areas and causes of wireless signal fluctuation within 40 percent FZ level. . The investigation was restricted to line-of-sight (LOS) links at frequency range of 2.1GHz in the Southern part of Nigeria (lat.40321 and 50331North) and (long.70251 and 80251),. Line-of-sight (LOS) signal measurements were carried out in randomly selected ten Local Government Councils in Akwa Ibom state. From the results obtained, the measured and calculated values of the Fresnel Zone clearance were in congruence. The variance between measured and calculated values ranged from 0.31m to 1.88m for 0.6 zones. Furthermore, from 0.22m to 3.13m, for 1.0 FZ number, and 0.26m to 3.03m, for 2.0 FZ number. Determined variation between the measured 1.0 FZ radius and 60 per cent no-obstruction radius at 1.0 FZ number was carried out. This showed lost radius index range of 2.06m to 9.12m. This analysis was done only for 1.0 zone number, since it was considered intermediate between the other two zones (0.6 and 2.0). The study further deduced that maximum signal strength was received between the ranges of 0.6 to 1.0 peak numbers for all locations. At 1.0 and 2.0 zone radius, the overall signal sent out were cut-off by some perceived obstructions along the line-of-sight path. The calculated and the measured path loss vary from 112.6dB to 134.2dB and 109.5dB to 130.2dB respectively, while their differences vary from 2.3dB to 4.0dB. The result further indicates that the strongest signal strength was established in Etinan at -80dB, and signal-to-noise ratio of 9dB as the lowest. The root means square error (RMS) index for path loss range from 2.28dB to 4.87dB. Comparatively, these results show a good agreement with earlier studies. The study inferred that urbanization, afforestation, etc. , have contributed largely to attenuation of signal strength along these routes. Relevant recommendations for further studies were made relating to signal obstruction caused by afforestation and urbanization.