Tag Archives: Refractivity

Effect of Secondary Radioclimatic Variables on Signal Propagation in Nsukka, Nigeria (Published)

This study presents the effects of Radioclimatic variables on signal propagation in Nsukka, Nigeria. The primary Radioclimatic data used in the study include temperature, pressure and humidity or water vapour pressure, while secondary radioclimatic data includes refractivity (N), refractive index (n) and effective earth’s radius (k-factor). The measurements of the primary variables were made at time interval of 30 minutes daily from August 2013 to July 2014. The results obtained show seasonal variation of the temperature and relative humidity. This leads to the increase in the values of radio refractivity and refractive index. The results also, show that the k-factor values for those months were at the range 1.555 – 1.653. This high values of k-factor is an indicator to the possible causes of signal interference in the study area.

Keywords: Nsukka, Refractivity, k-factor, refractive index

Atmospheric Refractivity over Abuja, Nigeria (Published)

Atmospheric refractivity at Abuja was investigated for disturbed days and quiet days during dry and rainy season. The result of the investigation showed that refractivity variation for disturbed and quiet days during dry and wet season over Abuja are governed by the changes in atmospheric parameters which conversely cause changes in refractive index. The correlation of refractivity with pressure, temperature and relative humidity for disturbed and quiet days indicated that relative humidity and pressure as well as temperature have great correlation effect for disturbed and quiet day in wet season as well as in dry season.

Keywords: Atmospheric Parameters, Correlation, Refractivity

A Test of the Relationship between Refractivity and Radio Signal Propagation for Dry Particulates (Review Completed - Accepted)

Radio waves or radio signals propagate through the atmosphere in wireless communication. They are affected mostly by variability in radio refractivity which leads to a decrease in their speed or rate of propagation which eventually cause propagation delay or attenuation in the troposphere. The hourly averages of radio refractivity for dry particulates during dry season (January) were calculated from the data obtained from the Nigeria Meteorological Agency (NIMET) when UHF broadcast signal measurement was taken for each hour throughout the whole day in Akure, Ondo state, Nigeria. However, the statistical correlation (with a correlation coefficient of -0.97) reveals that at different points when the refractivity was high (most especially at night and in the morning when the humidity was high) the signal strength was low and at the points when the refractivity was low (most especially during the day when the humidity was low due to high temperature) the signal strength was higher. Therefore, the higher the refractivity the lesser the signal strength at the point of observation in the troposphere i.e. they are inversely proportional to each other

Keywords: Dry particulates, Radio Signal, Refractivity, Troposphere