Signal Strength Variation and Propagation Profiles of UHF Radio Wave Channel in Ondo State, Nigeria

This study investigated the received signal strength and the propagation profiles for UHF channel 23, broadcast signal in Ondo State, Nigeria, at various elevation levels. The signal strength was measured quantitatively across the state along several routes with the aid of a digital field strength meter. A global positioning system (GPS) receiver was used to determine the elevation above ground level, the geographic coordinates and the line of sight of the various data points from the base station. Data obtained were used to plot the elevation and propagation profiles of the signal along measurement's routes. Results showed that the signal strength was strongest towards the northern parts with respect to distance compared to other routes with the same distance contrary to inverse square law. The threshold signal level for the station was 20dBµV which was recorded up to 50km line of sight from the transmitter towards the northern parts of the state where higher levels of elevation of data locations were recorded and 42km towards the southern parts with lower values of elevation. The propagation profiles for all the routes follow the elevation pattern of the study areas, with some farther locations recording higher signal strength compared to closer locations to the transmitter contrary to theoretical expectation. The overall results show that elevation above ground level is a key factor to be considered for UHF transmission and reception (location of transmitters, transmitting antenna's height, directivity and gain. Others are, transmitter output power, receiving antenna's height and gain) in the study areas.