QUANTIFICATION OF ELECTRIC FIELDS AND COVERAGE AREAS OF

TRANSMITTERS FOR DEPLOYING ADVANCED TRAVELLER

SYSTEM IN NIGERIA

BY

ADENODI, RAPHAEL ADEWALE PHY/97/9931 BSc (Ed), M. Tech.

A THESIS IN THE DEPARTMENT OF , SCHOOL OF SCIENCES, SUBMITTED TO THE SCHOOL OF POST GRADUATE STUDIES

IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF DOCTOR OF PHILOSOPHY (Ph. D) IN PHYSICS OF THE FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE, ONDO STATE IN NIGERIA.

JULY, 2014 ABSTRACT

There has been a downturn in the number of medium frequency - amplitude modulated (MF - AM) stations currently operating in Nigeria. This is due to the widespread use of frequency modulation (FM) band for broadcasting and the establishment of more stations.

Technically speaking, the decline was also motivated by the fact that noise inherent in the AM signal compared to that of FM and TV is huge. This study is aimed at assessing the coverage areas of some MF – AM transmitters over the Nigerian landmass. To achieve this, the electric field strengths of the radio signals were measured along some routes around the transmitters during the rainy and dry seasons and these were interpolated to generate primary, secondary and fringe coverage areas which were geo-referenced on the maps of the owner states. The seasonal variations in the coverage areas were deduced. The study also identified the possible locations of radio beacons for full Advanced Traveller Information Systems (ATIS) coverage of the states. The mean electric field strength in wet and dry seasons are 3.83 ± 0.62 mV/m and 3.06 ± 0.43 mV/m for Oyo

Radio, 4.05 ± 0.75 mV/m and 3.04 ± 0.32 mV/m for Kwara Radio, 3.36 ± 0.45 mV/m and 3.89 ±

0.54 mV/m for Voice of Ekiti, and 3.34 ± 0.46 mV/m and 3.13 ± 0.56 mV/m for Federal Radio

Corporation of Nigeria. The values are 3.28 ± 0.45 mV/m, 3.88 ± 0.30 mV/m and 3.90 ± 0.82 mV/m around Radio Jigawa, Radio Benue and Kano Radio respectively. Results obtained from the study also reveal that signals from digital MF - AM transmitter provide wider coverage area compared to signals from analogue transmitter of the same transmitter power. It is also revealed from the study that MF - AM signals can still be used satisfactorily for radio broadcasting and

ATIS if the signals are digitized.

CHAPTER 1

1.0 INTRODUCTION

1.1 Background Information

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation and includes the visible light. The medium wave frequency (MF) lies between 300 and 3000 kHz

(Seybold, 2005). Typical services available on this frequency band includes; mobile, navigation and broadcasting. Radio broadcasting is undertaken in the frequency range 525 - 1705 kHz in the medium wave band. The medium frequency amplitude modulated (MF-AM) band had been one of the most used broadcasting techniques for decades, allowing information to arrive at innumerable listeners within the localities. It exhibits covert coverage, which ensures no skip zone.

Wider coverage and better audio quality attract increased listeners’ interest and more patronage.

Analogue MF-AM has noisy audio quality and the coverage area is restricted by the ground electrical parameters and obstructions along the radio paths. Other communication services such as frequency modulated (FM) ; television and the Internet have replaced the MF-AM services in recent years. This has led to the reduction in the number of its transmitters operation in

Nigeria. Digital MF-AM transmitter provides wider coverage area and better audio quality compared to analogue of the same transmitter power (Melo et. al., 2007).

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