Analysis of Radio Wave Propagation Models for Interference Mitigation in Frequency Modulation (FM) Broadcasting at the VHF Band

Frequency Modulation (FM), in the VHF band, remains an essential medium for mass communication in the region, especially in developing nations where the radio serves as a vital source of information, education, as well as entertainment materials. In spite of its superior quality sound, along with the capacity to withstand noise, FM is presently experiencing immense interference because of the complex aspects of the propagation of radio waves, crowding of radio stations due to the increase in the number of radio stations, and changed environmental conditions. In this paper, the analytical aspects of radio waves’ propagation will be discussed as an attempt to reduce the levels of interferences that exist between radio stations that operate on close frequency parameters within the VHF frequency band. In particular, the study will seek to examine the propagation of Dominion FM with frequency 106.1 MHz and Fresh FM with frequency 105.9 MHz, both of which operate within Ibadan, the capital of Oyo State in Nigeria. The two radio stations operate close frequency parameters, which make them most appropriate to be included in the study. The research will be conducted through field studies along selected routes using the Software Defined Radio (SDR) devices, where the households will be assessed by measuring the Signal to Noise Ratio (SNR), and using the relationship between the radio signal and the signal frequency, the power will be expressed in terms of the received signal power, which will be used to evaluate the propagation of the radio waves in the two regions, and the results will be used to construct the percentage of signal strength between the two radio stations, thereby enabling the calculation of the Signal to Interference Ratio (SIR). The study results reveal scenarios that are most susceptible to interferences, while the investigation also evaluated the appropriateness of the radio propagation models for improving the Performance of the two radio stations within the FM frequency band in the VHF band in Nigeria generally.