Measurements of VHF Signal Strength for Terrestrial Broadcast Service in Minna, North Central Nigeria

Abstract

Preliminary calculations including the expected signal strength at the receiver is required for the design of a radio communication system in order to predict the behaviour of the radio signal. Signal strength measurement was made from a broadcasting station transmitting at a frequency of 91.2 MHz along a 7.15 Km path. Results from the experiment reveal that received signal strength (RSS) values were higher during the wet season as compared to lower values recorded during the dry season for the link. Also, the RSS was higher during the morning and evening/night hours while lower values were recorded during the afternoon time. Signal attenuation caused by atmospheric and environmental losses was calculated and for the dry season, average clear-air attenuation fluctuated between -1 dB to 0.6 dB while wet season values fluctuated between -1.5 dB and 0.9 dB. Also, the RSS was modeled using ITU-R P.526-12 to predict path losses due to diffraction over the earth’s curvature and result obtained show that this model underestimated the RSS for the radio link while 4 (0.22%) corresponded to cases of enhanced field strength out of the measured 1777 field strength data.