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Terrestial VHF / UHF Signal Strength Levels in Eastern Obolo and Ikot Abasi Communities of Akwa Ibom State, Nigeria

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Terrestial VHF / UHF Signal Strength Levels in Eastern Obolo and Ikot Abasi Communities of Akwa Ibom State, Nigeria IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 14, Issue 5, Ser. I (Sep.-Oct. 2019), PP 12-25 www.iosrjournals.org Terrestial VHF / UHF Signal Strength Levels in Eastern Obolo and Ikot Abasi Communities of Akwa Ibom State, Nigeria Aniefiok Otu Akpan Physics Department, Akwa Ibom State University, Nigeria Corresponding Author: Aniefiok Otu Akpan Abstract: Signal strength levels from Akwa Ibom Broadcasting Corporation (AKBC) television (Channel 45) and Nigerian Television Authority (NTA) channel 12 have been measured with a view to establishing the primary, secondary and fringe service areas of these signals at some locations in Eastern Obolo and Ikot Abasi Local Government Areas of Akwa Ibom State. Eastern Obolo and Ikot Abasi are densely forest zones that empty into the creeks that lead to the Atlantic Ocean in Akwa Ibom State. Propagation of electromagnetic waves in these areas has been quite challenging. CATV was used to measure signals of the TV station in dB, dBµv and dBmv. Signals received from this TV station at different locations of the study area using Radio Frequency Analyser with 24 channels spectrum ranging from 46-870MHz and an outdoor television antenna, 59(L) x 8.5(W) x 11(H) on a 10m pole showed that the signal strength received from VHF channel 45 ranged from 22dBµv to 51dBµv in Ikot Abasi and Eastern Obolo. 31.5dBµv signal was received by more than 55% of the area covered but others, especially the rural communities had signal below this value. In terms of path loss prediction, this closely agreed with Egli model when comparing the standard and calculated path loss. There was a drop in the received signals to about 11dB further in rural areas with thick vegetation. The poor signal received in these areas is not unconnected with the attenuations along the path of propagation from Uyo where the stations are located to these areas. The presence of thick vegetation, the atmosphere and other natural activities have greatly influenced the propagation of the signal. Some of the residents in these rural locations fell within the fringe zone while minority were in the secondary coverage zone as indicated in channel 12. These stations need to do more to boost the signal strength in the rural setting of this study. Keyword: Eastern Obolo, Ikot Abasi, Television Channel, UHF/VHF Signal, Signal propagation. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 28-10-2019 Date of Acceptance: 12-11-2019 ----------------------------------------------------------------------------------------------------------------------------- ---------- I. Introduction The television has become an important tool for information dissemination. It‟s importance in today‟s modern society cannot be over emphasized which include enhancement of communication and promoting education just to mention a few. Frequency bands such as VHF (Very High Frequency) and UHF (Ultra High Frequency) bands are assigned to stations for terrestrial broadcasting. As viewers tune to broadcast stations within and outside their localities, what is expected is the television to faithfully reproduce the exact audio and video features transmitted by the broadcasting station‟s transmitter. The structural content or shape of object, the tonal content or relative brightness, the motion of the object or kinematic content, sound, color or chromatic content and lastly the stereoscopic content also known as perspective should all be intact (Kenedy & David,1999). These contents are direct function of how good the signal is at the point of reception. In other word, they reflect the signal strength at such point. The signals are electromagnetic in nature and as such are subject to natural or man-made phenomena. Factors like the presence of hills, buildings, vegetation and the atmosphere have been found to have great influence on the propagation of this signal in different regions. The areas of reception have been classified into primary, secondary and fringe service area (Ajewole et al,2014), (Oyetunji,2013). Based on environmental influences, the signal may decreases from primary to fringe zone. When an electric current flows through a conductor, it produces a time-varying electric field which in turn acts as a source of magnetic field. These two fields created can sustain and interact with each other giving rise a special form of energy known as electromagnetic wave (Griffith, 1999). According to Maxwell‟s equations, both electric and magnetic fields which form the electromagnetic disturbance are sinusoidal functions of time and position, and characterized by frequency and wavelength. These equations and direction of propagation define the basic principle undergirding the operation of electromagnetic wave as a combination of Gauss‟s law of electric fields, Gauss‟s law of magnetic fields, Ampere‟s law and Faraday‟s law (Griffith, 1999). The equations are as follows: DOI: 10.9790/2834-1405011225 www.iosrjournals.org 12 | Page Terrestial VHF / UHF Signal Strength Levels in Eastern Obolo and Ikot Abasi Communities of ∮ 퐸. 푑퐴 = 푄푒푛푐푙/휖˳ (1) Equation (1) implies that the surface integral of E over any closed surface equals 1/휖 multiplied by the total charge Qencl , where E is the electric field and A represents the area. (ii) ∮ 퐵. 푑퐴 = 0. (2) Equation (2) states that the surface integral of B over any closed surface is zero, where B is the magnetic field. 푑Φ (iii) ∮ 퐵. 푑푙 = 휇˳(푖˛ + 휀˳ 퐸) (3) 푑푡 This is also known as Ampere‟s law. It implies that both conduction and displacement current act as sources of magnetic field; where 휀˳ is the permittivity of free space, 휇˳ the permeability of free space, and Φ퐸 the electric flux. 푑Φ (iv) ∮ 퐸. 푑푙 = − 퐸 (4) 푑푡 Equation (4) is Faraday‟s law and implies that a changing magnetic flux induces an electric field. The Heaviside version of this equation using Laplace transform is shown in Equations (5) to (8) below: ∇. 퐸 = 0 (5) 휕퐵 ∇xE = − (6) 휕푡 ∇. 퐵 = 0 (7) 휇˳휖˳휕퐸 ∇푋퐸 = (8) 휕푡 Deploying the curl of curl to these equations, we obtain Equations (9) and (10) as presented below: 휕 휇˳휖˳휕²퐸 ∇x ∇xE = − ∇xB = − (9) 휕푡 휕푡² 휕 휇˳휖˳휕²퐸 ∇x ∇xB = − ∇xE = − (10) 휕푡 휕푡² Further to the above, applying the vector identity, Equation (11) is derived as: ∇x ∇xV = ∇. ∇. V − ∇²V (11) Where V is any vector function in space. And Equation (12), ∇2V = ∇. ∇. V (12) Where ∇V is a dyadic which when operated on by the divergence operator ∇⋅ yields a vector. Since ∇. E = 0 ∇. B = 0 Then, the first term on the right in the identity vanishes and the wave equations is obtained as presented below: 휕2퐸 − 푐˳2. ∇2E = 0 (13) 휕푡² 휕2퐵 − 푐˳2. ∇2B = 0 (14) 휕푡² Where C in Equation 15: 1 푐˳ = = 2.99792458 x 108 m/s (15) 휇˳휖˳ is the speed of light in free space. Each of these radiations has both frequency and wavelength range called bands, and are expressed below [7]: Radio Waves: 10 cm to 10 km wavelength; Microwaves: 1 mm to 1 m wavelength. (1 GHz = 109 Hz); P band: 0.3 - 1 GHz (30 - 100 cm); L band: 1 - 2 GHz (15 - 30 cm); S band: 2 - 4 GHz (7.5 - 15 cm); C band: 4 - 8 GHz (3.8 - 7.5 cm); X band: 8 - 12.5 GHz (2.4 - 3.8 cm); Ku band: 12.5 - 18 GHz (1.7 - 2.4 cm); K band: 18 - 26.5 GHz (1.1 - 1.7 cm); Ka band: 26.5 - 40 GHz (0.75 - 1.1 cm); Infrared: 0.7 to 300 µm wavelength; Near Infrared (NIR): 0.7 to 1.5 µm; Short Wavelength Infrared (SWIR): 1.5 to 3 µm; Mid Wavelength Infrared (MWIR): 3 to 8 µm; Long Wavelength Infrared (LWIR): 8 to 15 µm; Far Infrared (FIR): longer than 15 µm; Visible Light: It ranges from about 400 nm (violet) to about 700 nm (red);Red: 610 - 700 nm; Orange: 590 - 610 nm; Yellow: 570 - 590 nm; Green: 500 - 570 nm; Blue: 450 - 500 nm; Indigo: 430 - 450 nm; Violet: 400 - 430 nm; Ultraviolet: 3 to 400 nm; X-Rays and Gamma Rays; Nakanishi (2013) indicated that there are other approaches that have the ability to track the passage of electromagnetic waves ( Lee, 1982). The radial electric field surrounding such electron is given by the Equation (16) below: 1 푒 퐸푟 = ∗ 2 (16) 4휋휀0 푟 The condition stated by Equation (16) holds only for a stationary electron; but changes when such an electron is moving. Example: a current-carrying wire. The moving electron which produces current is also responsible for the magnetic field around it. According to Griffiths (1999), any new field (electromagnetic radiation) produced by an accelerating electron depends on the acceleration of the electron and the reciprocal of the distance of the electron from the nucleus. This theory is illustrated in Equation (17) below: 1 푟 푠푖푛휃 퐸휃 = 푒 ∗ ∗ 2 (17) 4휋휀0 푐 푟 DOI: 10.9790/2834-1405011225 www.iosrjournals.org 13 | Page Terrestial VHF / UHF Signal Strength Levels in Eastern Obolo and Ikot Abasi Communities of where 퐸휃 is the pulse of electromagnetic radiation, 푒 is the electronic charge, r is the acceleration, c is the speed of light, r the distance from the nucleus, and the angle between the changing fields. The amount of radiation leaving the system also depends of the length of the current-carrying conductor and the wavelength of the current flowing through it. Based on this, electromagnetic radiation can be described as an energy that is transmitted in form of electromagnetic wave either through space or a material medium. Attenuation of Electromagnetic radiations This is one of the major setbacks in the propagation of electromagnetic waves when it leaves its source. Electromagnetic waves get attenuated as they travel outwardly.
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