Empirical Field Strength Model for Terrestrial Broadcast in VHF Band in Makurdi City, Benue State, Nigeria

Abstract

The ability to predict the minimum power a transmitter must radiate to give an acceptable quality of coverage over a predetermined service area is very imperative. This work adapted some field strength models that are best suitable for Makurdi city in Benue State, Nigeria. Some existing field strength models are optimised to suit Makurdi city using a VHF television signal of Nigeria Television Authority (NTA), Makurdi. The models are free space, Hata, ITU-R P.529-3 and ERC Report 68 models. NTA, Makurdi transmits at a frequency of 210.25 MHz for video signal. Measurement of the video signal levels was done along four radial routes from the transmitting station. A digital signal level meter and Global Positioning System (GPS) was used to measure the signal level of the transmitted signal from the station along these routes and to measure the corresponding distances away from the base of the transmitting antenna respectively. The results obtained, after processing and computation of the data; show that the free space model gives more accurate prediction for field strength in Makurdi city, after general modification, with the correction factor of -29.85 and Root Mean Square Error of 4.12 dBµV/m