Point to Point Microwave
Point to Point Microwave
Batangas State University College of Engineering, Architecture, Fine Arts and Computing Sciences Electronics and Engineering Department
Point to Point Microwave Design
Submitted by: Brondial, Marlon Ereño, Aileen M. Recio, Jeselle V. De Padua, Kristian Mhar G.
Submitted to: Engr. Albertson D. Amante
Chapter I. The Problem and It’s Background I – A. Introduction I – B. Background of the Location I – C. Objectives I – D. Significance of the Study I – E. Definition of Terms
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Chapter II. Review of Related Literature II – A. Microwave System Overview II – B. Microwave Transmission II – C. Frequency Ranges II – D. Microwave sources II – E. Microwave Path Design II – F. Radio Path Profiling
18 21 21 22 23 24
Chapter III. Design Methodology III – A. Site Selection III – B. Radio Path Profiling III – C. Transmission Calculations
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Chapter IV. PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA IV – A. Site Selection IV – B. Path Calculation IV – C. Topographical Site of the Map IV – D. Transmission Calculations IV – E. Microwave Path Data Calculation Sheet
55 55 56 69 78
Chapter V. Summary, Conclusions and Recommendations V – A. Summary V – B. Conclusions V – C. Recommendations
79 80 82
CHAPTER I THE PROBLEM AND ITS BACKGROUND
Microwave technology has been used for communication purposes since the 1940’s. Despite of the domination of fiber optics, microwave communication is still use because it offers very high reliability and has relatively low construction cost compared with fiber optic cabling. A microwave communication system does not require physical cables or expensive attenuation equipment (devices that maintain signal strength during transmission). Mountains, hills and rooftops provide inexpensive and accessible bases for microwave transmission towers. It also used to design five 9’s or 99.999% of reliability.
Microwave transmission is the transmitting of information or energy by the use of radio waves whose wavelengths are conveniently measured in small numbers of centimeter; these are called microwaves. This portion of the electromagnetic spectrum falls between 1000 megahertz and 100,000 megahertz. These correspond to wavelengths from 30 centimeters down to 1.0 cm.
Microwave is a term applied to identify electromagnetic waves above 1000 megahertz in frequency because of the short physical wavelengths of these frequencies. Because of their small wavelength that allows conveniently sized antennas to direct them in narrow beams, microwaves are wide used for point-topoint communications. This allows nearby microwave equipment to use the same frequencies without interfering with each other, as lower frequency radio waves do. Another advantage is that the high frequency of microwaves gives the microwave band a very large information-carrying capacity; the microwave band has a bandwidth 30 times that of all the rest of the radio spectrum below it. A
disadvantage is that microwaves are limited to line of sight propagation; they cannot pass around hills or mountains as lower frequency radio waves can.
Microwave communication is the transmission of signals via radio using a series of microwave towers. Microwave communication is known as a form of “line of sight” communication, because there must be nothing obstructing the transmission of data between these towers for signals to be properly sent and received. It is also affected greatly by environmental constraints like rain fade. It is also sensitive to high pollen count and has very limited penetration capabilities through obstacles through obstacles such as high, buildings and trees.
B. Background of the Location
Davao del Norte and once known simply as Davao, is a province of the Philippines located in the Davao Region in Mindanao. Its capital city is Tagum City. It borders the province of Agusan del Sur to the north, Bukidnon to the west, Compostela Valley to the east, and the city of Davao to the south. Davao also includes Samal Island to the south in the Davao Gulf. The province of Compostela Valley used to be part of Davao until it was made into an 5
independent province in 1998. Before 1967, the four provinces—Davao, Davao Oriental, Davao del Sur, and Compostela Valley—were once a single province named Davao. The Davao Region covers this historic province. The Province is exactly located at the earth’s coordinates of 7°21’ N, 125°42’ E. Davao del Norte is the 42nd largest province out of 80 provinces having an area of 3,426.97 km2 or 1,323.16 sq. mi.
Figure 1.3 Path from Panabo to Kapalong.
Davao del Norte is subdivided in 8 municipalities and 3 cities. Through the use of Google Earth and a topographic map of the Davao del Norte Province, the researchers made an extensive study of the said area to properly locate a suitable position of the microwave system. It was then decided to take Panabo and Kapalong Municipalities.
Panabo City is a 1st class city near Davao City in the province of Davao del Norte, Philippines. The city has an area of 249 square kilometers. It has a population of 164,035 people in 32,807 households. It is exactly located at the 6
earth’s coordinates of 7°26’38.02‖ N, 125°46’35.84″E. Panabo has an area of 251.23 km2 or 97.00 sq. mi. It is politically subdivided into 40 barangays
Figure 1.3 Panabo City – Tower A
Panabo is known as the “Banana Capital of the Philippines” due to numerous banana plantations scattered throughout the city. In fact, Panabo is the home of the world’s biggest banana plantation, which is owned by the Tagum Agricultural Development Company (TADECO), which covers around 6,900 hectares of banana fields and produce millions of boxes of export-quality bananas annually. The city itself cultivated 40% of its land or around 10,000 hectares into planting export-quality bananas, which is better known as “Cavendish Bananas”. Thus, banana cultivation and exportation are the main economic lifeblood of the city.
Figure 1.4 Kapalong – Tower B
class municipality in
the province of Davao
Norte, Philippines. According to the census, it has a population of 68,593 people in 13,843 households. It was one of the oldest towns in Davao del Norte Province. It has coordinates of 7°37’46.81‖ N, 125°43’03.52”E. It is politically subdivided into 14 barangays.
The main objective of this study is to design a Point-to-Point Microwave Communication System from Panabo City , Davao del Norte to Kapalong, Davao del Norte.
Specifically, the researchers must accomplish the following objectives for the completion of the study: 1. To select the best location for the point to Point Microwave Communication System. 2. To be able to know the parameters used in designing a Point to Point Microwave Communication System. 8
3. To be able to obtain path calculations. 4. To choose the appropriate equipment such as waveguides, antennas, transceivers, and tower design to be used for transmission. 5. To attain a percentage reliability that is more than or equal to 99.999%
D. Significance of the Study
Communication System that will link the sites Panabo, Davao del Norte and Kapalong, Davao del Norte. The parameters and locations of sites are considered by the standards of the CCIR Recommendation 384-4.
The study focuses on the design, discussion and analysis of different parameters that affect the point-to-point microwave communication system .Selection of the characteristics of radio equipment, towers, waveguides and antennas are also pointed out in this research for the efficiency of the design.
The study is limited in the descriptive analysis of the design parameters and the selection of sites. Thus, the study did not include the financial statement of the design and the material implementation since it must be cleared that it is for academic purposes only.
E. Definitions of Terms
Antenna. An antenna or aerial as it is sometimes called is one or more electrical conductors of a specific length that radiate radio waves generated by a transmitter or that collect radio waves at the receiver. There are literary hundreds of different types of antennas in use today. It is some form of electrical conductor. It may be a length of wire, a metal rod, or a piece of tubing. Many different sizes 9
and shapes are used. The length of the conductor is dependent upon the frequency of transmission. (Communication Electronics by Frenzel)
Antenna Efficiency. It is defined as the ratio of the power radiated by the antenna to the power delivered to the feed point. It is also defined as the ratio of the radiation resistance to the total antenna resistance. (Communication Electronics by Frenzel)
Antenna gain. The ratio of the power required at the input of a loss-free reference antenna to the power supplied to the input of the given antenna. In antenna design, gain is the logarithm of the ratio of the intensity of an antenna’s radiation pattern in the direction of strongest radiation to that of a reference antenna. If the reference antenna is an isotropic antenna, the gain is often expressed in units of dBi (decibels over isotropic). Sometimes, the dipole antenna is used as the reference (since a perfect isotropic reference is impossible to produce), in which case the gain of the antenna in question is measured in dBd (decibels over dipole). (Communication Electronics by Frenzel)
Antenna Polarization. It is the sense of the wave radiated by an antenna; this can be horizontal, vertical, elliptical or circular depending on the design and application. (Communication Electronics by Frenzel)
Attenuation. It is the reduction of the strength of the transmitted signal. (Electronic Communications Systems by Wayne Tomasi)
Balanced line. It is made up of two parallel conductors spaced from one another by a distance of ½ (in.) up to several inches. The term ―balanced line‖ means that the same current flows in each wire with respect to ground, although the direction of current in one wire is 180° out of phase with the current in the other wire. Neither wire is connected to ground. (Communication Electronics by Frenzel) 10
Bandwidth. It is the spectrum space occupied by a signal, the frequency range of a transmitted signal, or the range of frequencies accepted by the receiver. It is the difference between the upper and lower frequencies of the range in question. (Communication Electronics, Frenzel)
Characteristic impedance. The ratio of the amplitude of a single voltage wave to its current wave. (Electromagnetics by William Hayt)
Coaxial cable. Other type of transmission line usually just called coax. It consist of a solid-center conductor surrounded by a plastic insulator such as Teflon. Over the insulator is a second conductor, a tubular braid or shield made of fine wires. An outer plastic sheath protects and insulates the braid. (Communication Electronics, Frenzel)
Demodulation. It is the reverse process of modulation and occurs at the receiver side of the communication system. (Electronic Communications Systems by Wayne Tomasi)
Dipole antenna. Two wires pointed in opposite directions arranged either horizontally or vertically, with one end of each wire connected to the radio and the other end hanging free in space. (Electronic Communications Systems by: Frenzel)
Efficiency. The ratio of output-signal power compared to the total input power generally expressed as a percentage. (Wikepedia)
Electric field. The field associated with voltage. It exerts a force on any electric charge placed in it. (Electronic Communications Systems by: Frenzel)
Electrical length. The physical length of the wire multiplied by the ratio of the speed of wave propagation in the wire. (Wikipedia)
Electromagnetic wave. A transverse wave composed of electric and magnetic field component which are acting perpendicularly to each other. (Electronic Communications Systems by Wayne Tomasi)
Elevation. The elevation of a geographic location is its height above a fixed reference point, often the mean sea level. Elevation, or geometric height, is mainly used when referring to points on the Earth‟s surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit. (http://en.wikipedia.org/wiki/Elevation)
Equivalent isotropic radiated power (EIRP). It is the actual RF power as measured in the main lobe (or focal point) of an antenna. It is equal to the sum of the transmit power into the antenna (in dBm) added to the dBi gain of the antenna. Since it is a power level, the result is measured in dBm. . (www.wikepedia.com)
Fade Margin. Is defined as the difference between the signal level received and the signal needed for good reception.(www.wikepedia.com)
Fading. Any varying of phase, polarization, and or level of a received signal.(Electronic Communications Systems by Wayne Tomasi)
Feed horn. An antenna system that handles the incoming waveform from the dish to the focal point. (Electronic Communications Systems by Wayne Tomasi)
Free-space loss. It is the signal attenuation that would result if all absorbing, diffracting, obstructing, refracting, scattering, and reflecting influences 12 were sufficiently removed so as to have no effect on its propagation. (Electronic Communications Systems by Wayne Tomasi)
Frequency. It is the number of complete cycles per second existing in any form of wave motion, such as the number of cycles per second of an alternating current (Communications Engineering Formulas and Dictionary by Santos S. Cuervo)
Fresnel Zone. The area that the signal spreads out into is called the Fresnel zone. If there is an obstacle in the Fresnel zone, part of the radio signal will be diffracted or bent away from the straight-line path. The practical effect is that on a point-to-point radio link, this refraction will reduce the amount of RF energy reaching the receive antenna. (www.wikepedia.com)
Hertz antenna. It is a set of terminals that does not require the presence of a ground for its operation. (Electronic Communications Systems by: Frenzel)
Impedance. It is a complex quantity that is the combination of resistance and reactance. It is the opposition offered by a transmission medium to alternating current. The symbol used is Z and the unit is ohms. (Electromagnetics by William Hayt)
Input impedance. The impedance of a transmission line at any point that is defined as the complex ratio of voltage to current at any point. (Electromagnetics by William Hayt)
Interference. It is any disturbance that produces an undesirable response or degrades a signal. (Communications Engineering Formulas and Dictionary by Santos S. Cuervo)
Ionosphere. The most important region of the atmosphere extending from 31 miles to 250 miles above sea level.(Communications Engineering, Black Book by Christopher)
Isotropic radiator. Antenna from which the energy is transmitted equally in all direction. (Electronic Communications Systems by: Frenzel)
Latitude. It is defined as the angle between the line drawn from a given point on the surface of the earth to the geocenter and the line between the geocenter and the equation.(Electronic Communications System Fundamentals Through Advanced by Wayne Tomasi)
Line Loss. It is the power loss in the transmission line, usually expressed in Decibels.(www.wkepedia.com)
Line of Sight. It is characteristic of most radio signals with a frequency above approximately 30 MHz(Electronic Communications System Fundamentals through Advanced by Wayne Tomasi)
Loaded antenna. Active antenna having an elongated portion of appreciable electrical length and having additional inductance or capacity directly in series or shunt with the elongated portion so as to modify the standing wave pattern existing along the portion or to change the effective electrical length of the portion (Electronic Communications Systems by Wayne Tomasi)
Magnetic field. The field associated with current because it tends to exert a force on any magnetic pole placed in it. (Electromagnetics by William Hayt)
Microwave communication system. It is any communication system that uses electromagnetic waves which are in the range of microwave frequency. (Electronic Communications Systems by Wayne Tomasi) 14
Microwaves. A short-wavelength, high-frequency signals that occupy the Electromagnetic spectrum 1,000 MHz (1 GHz) to 1,000 GHz (1 terahertz). (Electronic Communications Systems by Wayne Tomasi)
Microwave power transmission (MPT). It is the use of microwaves to transmit power through outer space or the atmosphere without the need for wires. It is a subtype of the more general wireless energy transfer methods. (Wikipedia)
Mismatch. Term used to describe a difference between the output impedance of a source and the input impedance of a load. A mismatch prevents the maximum transfer of power from source to load.
Multipath fading. The most common type of fading encountered, particularly on LOS radio links. It is the principal cause of dispersion, which is particularly troublesome on digital troposcatter and high bit rate LOS links. (Electronic Communications Systems by Wayne Tomasi)
Output impedance. The ratio of voltage to current at the output (EOUT/IOUT) end; this is the impedance presented to the load by the transmission line and its source. (Electromagnetics by William Hayt)
Path Profile. It is a graphical representation of the path travelled by the radio waves between the two ends of a link. The Path Profile determines the location and height of the antenna at each end of the link, and it insures that the link is free of obstructions, such as hills, and not subject to propagation losses from radiophenomena, such as multipath reflections. (Electronic Communications System Fundamentals Through Advanced by Wayne Tomasi)
Parabolic antenna. It is also known as parabolic dish and parabolic mirror. It is a reflective device, commonly formed in the shape of a paraboloid of revolution. Parabolic reflectors can either collect or distribute energy such as light, sound, or radio waves. It is the most common microwave antenna. It consists of an antenna feed, which radiates its power into a parabolic-shaped reflecting surface. The parabolic reflector concentrates the microwave power back along the antenna axis. The gain, receiving area, and beam width are determined by the parabolic reflector.(www.wikepedia.com)
Polarization. It is a phenomenon peculiar to transverse waves, i.e., waves that vibrate in a direction perpendicular to their direction of propagation. It also refers to the physical orientation of the radiated waves in space. Waves are said to be polarized if they all have the same alignment in space.
Radiation losses. Occur because some magnetic lines of force about a conductor do not return to the conductor when the cycle alternates. (Electronic Communications Systems by Wayne Tomasi)
Radio waves. Electromagnetic waves whose frequency spectrum extends over a range from somewhat above the frequency of audible sound waves to somewhat below the frequency of heat and light Communications Systems By Wayne Tomasi) waves. (Electronic Radomes. Composed of panels, which when assembled form a truncated spherical shell to protect the enclosed antenna from the environment. (Wikipedia)
Reflection coefficient. It is the ratio of the amplitude of the reflected wave to the amplitude of the incident wave. In particular, at a discontinuity in a transmission line, It is the complex ratio of the electric field strength of the reflected wave to that of the incident wave. This is typically represented with a 16
Gamma.(Electronic Communications System Fundamentals Through Advanced by Wayne Tomasi)
Scanning. Process in which the antenna beams is repeatedly moved over an area in space, such as in radar. (Wikipedia)
Skin Effect. It is a phenomenon observed in the propagation of high frequency wave signal in the transmission line where the electrons travel near the surface of the conductor. (Electronic Communications System Fundamentals Through Advanced by Wayne Tomasi)
Transmission line. Device designed to guide electrical energy from one point to another. It is used to transfer the output RF energy of a transmitter to an antenna. (Electromagnetics by William Hayt) Transmission Tower. It is a rectangular in plan and is not steadied by guy wires. It is subjected to a number of forces; its own weight, the pull of the cables at the top of the tower, the effect of wind and ice on the cable, and the effect of wind on the tower itself. (Electronic Communications System Fundamentals Through Advanced by Wayne Tomasi)
Wavefront. It is a surface of constant phase. The portion of a wave envelope that is between the beginning zero point and the point at which the wave reaches its crest value, as measured either in time or distance. (Electronic Communications System Fundamentals Through Advanced by Wayne Tomasi)
Waveguides. It is any of a class of devices that confines and directs the propagation of electromagnetic waves, such as radio waves, infrared rays, and visible light. Waveguides take many shapes and forms. Typical examples include hallow metallic tubes, coaxial cables, and optical fibers.(Electronic System Fundamentals Through Advanced by Wayne Tomasi) 17
CHAPTER II REVIEW OF RELATED LITERATURE
A. Microwave System Overview
Microwaves are radio waves with wavelengths ranging from as long as one meter to as short as one millimetre, or equivalently,
with frequencies between 300 MHz (0.3 GHz) and 300 GHz. This broad definition includes both UHF and EHF (millimeter), and various sources use different boundaries. In all cases, microwave includes the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum, with RF engineering often putting the lower
boundary at 1 GHz (30 cm), and the upper around 100 GHz (3 mm).
Apparatus and techniques may be described qualitatively as “microwave” when the wavelengths of signals are roughly the same as the dimensions of the equipment, so that lumped-element circuit theory is inaccurate. As a
consequence, practical microwave technique tends to move away from the discrete resistors, capacitors, and inductors used with lower-frequency radio waves. Instead, distributed circuit elements and transmission-line theory are more useful methods for design and analysis. Open-wire and
coaxial transmission lines give way to waveguides and strip line, and lumpedelement tuned circuits are replaced by cavity resonators or resonant lines. Effects of reflection, polarization, scattering, diffraction, and atmospheric
absorption usually associated with visible light are of practical significance in the study of microwave propagation. The same equations of electromagnetic theory apply at all frequencies.
The prefix “micro-” in “microwave” is not meant to suggest a wavelength in the micrometer range. It indicates that microwaves are “small” compared to waves used in typical radio broadcasting, in that they have shorter wavelengths. The boundaries between far infrared light, terahertz radiation, microwaves, 18
and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study.
A microwave system is a system of equipment used for microwave data transmission. The typical microwave system includes radios located high atop microwave towers, which are used for the transmission of microwave communications using line of sight microwave radio technology.
A microwave system is composed of at least two microwave towers. At the top of these towers are microwave antennas. These antennas are what allow the transmitter hardware of the microwave system to transmit data from site to site. The area between the microwave system components must be clear of any major structures, such as tall buildings, mountains, or other objects that could potentially obstruct microwave transmission. Only when this has been achieved can data travel through the microwave system. This is why microwave communication is categorized as a ―line of sight‖ technology. When planning a microwave radio system, one must remember the requirements of microwave equipment. Microwave antennas must be placed at the top of tall radio towers to provide a clear line communication path. This allows the microwave system data to travel the long distances required by telecommunications service providers.
Line-of-sight propagation refers to electro-magnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line. The rays or waves may be diffracted, refracted, reflected, or absorbed by atmosphere and obstructions with material and generally cannot travel over the horizon or behind obstacles.
In the United States, radio channel assignments are controlled by the Federal Communications Commission (FCC) for commercial carriers and by the National Telecommunications and government systems. Information Administration (NTIA) for The FCC’s regulations for use of spectrum establish eligibility rules, permissible use rules, and technical specifications. FCC regulatory specifications are intended to protect against interference and to promote spectral efficiency. Equipment type acceptance regulations include transmitter power limits, frequency stability, out-of-channel emission limits, and antenna directivity.
The International Telecommunications Union Radio Committee (ITU-R) issues recommendations on radio channel assignments for use by national frequency allocation agencies. Although the ITU-R itself has no regulatory power, it is important to realize that ITU-R recommendations are usually adopted on a worldwide basis.
Table 2.1 Microwave Frequency Bands
Letter Designation L band S band C band X band Ku band K band Ka band Q band U band
Frequency range 1 to 2 GHz 2 to 4 GHz 4 to 8 GHz 8 to 12 GHz 12 to 18 GHz 18 to 26.5 GHz 26.5 to 40 GHz 30 to 50 GHz 40 to 60 GHz 20
V band E band W band F band D band
50 to 75 GHz 60 to 90 GHz 75 to 110 GHz 90 to 140 GHz 110 to 170 GHz
B. Microwave Transmission
Microwaves are widely used for point-to-point communications because their small wavelength allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna. This allows nearby microwave equipment to use the same frequencies without interfering with each other, as lower frequency radio waves do. Another advantage is that the high frequency of microwaves gives the microwave band a very large information-carrying capacity; the microwave band has a bandwidth 30 times that of all the rest of the radio spectrum below it. A disadvantage is that microwaves are limited to line of sight propagation; they cannot pass around hills or mountains as lower frequency radio waves can.
Microwave radio transmission is commonly used in point-to-point communication systems on the surface of the Earth, in satellite communications, and in deep space radio communications. Other parts of the microwave radio band are used for radars, radio navigation systems, sensor systems, and radio
C. Frequency Ranges
The frequency range of a system is the range over which it is considered to provide a useful level of signal with acceptable distortion characteristics. A listing of the upper and lower limits of frequency limits for a system is not useful without a criterion for what the range represents. 21
Many systems are characterized by the range of frequencies to which they respond. Musical instruments produce different ranges of notes within the hearing range. The electromagnetic spectrum can be divided into many different ranges such as visible light, infrared or ultraviolet radiation, radio waves, X-rays and so on, and each of these ranges can in turn be divided into smaller ranges. A radio communications signal must occupy a range of frequencies carrying most of its energy, called its bandwidth. Allocation of radio frequency ranges to different uses is a major function of radio spectrum allocation.
D. Microwave sources
Vacuum tube devices operate on the ballistic motion of electrons in a vacuum under the influence of controlling electric or magnetic fields, and include the magnetron, klystron, traveling-wave tube (TWT), and gyrotron. These devices work in the density modulated mode, rather than the current modulated mode. This means that they work on the basis of clumps of electrons flying ballistically through them, rather than using a continuous stream.
Low power microwave sources use solid-state devices such as the fieldeffect transistor (at least at lower frequencies), tunnel diodes, Gunn diodes, and IMPATT diodes.
A maser is a device similar to a laser, which amplifies light energy by stimulating photons. The maser, rather than amplifying light energy, amplifies the lower frequency, longer wavelength microwaves and radio frequency emissions. The sun also emits microwave radiation, and most of it is blocked by Earth’s atmosphere.
The Cosmic Microwave Background Radiation (CMBR) is a source of microwaves that supports the science of cosmology’s Big Bang theory of the origin of the Universe.
E. Microwave Path Design
Microwave is becoming a popular choice over wire line transport. It is an attractive option for many reasons, especially as radio equipment costs decrease. Low monthly operating costs can undercut those of typical T1 expenses, proving it more economical over the long term.
Carriers also are attracted to its modular and expandable characteristics. Network operators like the fact that they can own and control microwave radio networks instead of relying on other service providers for network components.
Like many carriers, you may be planning to jump on the microwave bandwagon. But before you move forward, make sure you understand all of the design considerations that will affect your deployment.
The following tasks are some of the fundamental components of microwave path design:
Determining whether a proposed path is “line-of-sight.” Evaluating path clearances with regard to refractive effects. Evaluating path clearances with regard to Fresnel zones. Considering path reflections. * deriving a power budget and the fade margin. Path reliability
F. Radio Path Profiling
1. Equivalent Earth Profile
A path profile plotted on a rectangular graph paper with no earth curvature and with the microwave beam drawn as a straight line between the antennas. It represents conditions when the beam has a curvature identical to that of the earth and the equivalent earth radius, k, is equal to infinity. This is one of the extreme conditions that must be investigated when making a study of the effect of abnormal atmospheric conditions on microwave propagation over a particular path.
2. Earth’s Curvature
One must account for the curvature of the earth when determining the altitude of a target. Distant targets, which are close to the ground, cannot be seen by radar because they will be below the horizon.
The relative curvature of the earth and the microwave beam is an important factor when plotting a profile chart. Although the surface of the earth is curved, a beam of microwave energy tends to travel in a straight line. However, the beam is normally bent downward a slight amount by atmospheric refraction. The amount of bending varies with atmospheric conditions. The degree and direction of bending can be conveniently defined by an equivalent earth radius factor, k. The height of a distant target that is above the horizon will be underestimated if the curvature of the earth is not taken into account. For example, the height of the target on the figure below would be underestimated as ―h‖ rather than the actual height ―H‖.
Figure 2.1 Explanation of Earth’s Curvature
3. Effects of Earth’s Curvature
Distant targets, which are close to the ground, cannot be seen by a radar because they will be below the horizon.
Figure 2.2 Effect of Earth’s Curvature
The height of a distant target that is above the horizon will be underestimated if the curvature of the earth is not taken into account. For example, the height of the target on the figure below would be underestimated as “h” rather than the actual height “H”.
A second effect, called refraction, also affects the path the electromagnetic energy will take as it propagates through the atmosphere. Normally, because the atmosphere’s density decreases rapidly with height, the radar beam will be deflected downward, much like light passing through a glass prism. In extreme cases, where 24 temperature increases with height and dry air overlays warm air, (a condition often found along coastlines), the beam can bend down dramatically and even strike the ground. Meteorologists call this effect “anomalous propagation”. Both the curvature of the earth and normal atmospheric refraction must be accounted for when determining the position of a target.
4. Free Space Loss
The free space path loss, also known as FSPL is the loss in signal strength that occurs when an electromagnetic wave travels over a line of sight path in free space. In these circumstances there are no obstacles that might cause the signal to be reflected refracted, or that might cause additional attenuation. The free space path loss calculations only look at the loss of the path itself and do not contain any factors relating to the transmitter power, antenna gains or the receiver sensitivity levels.
Fig.2.3 Free Space Diagram
Free space loss is the loss in power of an of an electromagnetic wave, such as a radio signal as it travels from the transmitter to the receiver that is associated with the phenomenon of beam divergence and the inverse square law of electromagnetic radiation. It is usually included in path loss calculations, together with other transmission factors, to ensure that the power of a transmitter is sufficient to send a receivable signal to a suitably sensitive receiver.
Also, free space loss is the loss in signal strength that would result if all absorbing, diffracting, obstructing, refracting, scattering, and reflecting influences were sufficiently removed so as to have no effect on its propagation.
Free space loss is primarily caused by beam divergence, i.e., signal energy spreading over larger areas at increased distances from the source, and by the inverse square law of electromagnetic radiation.
As the name implies, free space loss assumes the transmitter and receiver are both located in free space and does not consider other sources of loss such as reflections, cable, connectors, etc. Similarly it does not take account of gains from particular antennas.
Free space power loss is proportional to the square of the distance between the transmitter and receiver and also proportional to the square of the frequency of the radio signal.
A particularly convenient way to express free space loss is in terms of dB. The loss can be expressed as:
FSLdB = 20log D+ 20logf + K Where:
D is the distance, f is the frequency, and K is a constant that depends on the units used and details of the radio link. If d is measured in meters, f in Hz, and the link uses isotropic antennas, the expression becomes:
FSLdB = 20log D+ 20logf – 147.5 As an example, the FSL (dB) of a 1000 meter link operating at 1GHz using isotropic antennas is 92.5 dB. Very useful for fast calculation is expression where d is measures in km and f in MHz (link uses isotropic antennas)
FSLdB = 32.4 20log+ D 20log f 5. Fading
Fading is the distortion that a carrier-modulated telecommunication signal experiences over certain propagation media. A fading channel is a communication channel that experiences fading. In wireless systems, fading is due to multipath propagation and is sometimes referred to as multipath
In wireless communications, the presence of reflectors in the environment surrounding a transmitter and receiver create multiple paths that a transmitted signal can traverse. As a result, the receiver sees the superposition of multiple copies of the transmitted signal, each traversing a different path. Each signal copy will experience differences in attenuation, delay and phase shift while travelling from the source to the receiver. This can result in either constructive or destructive interference, amplifying or attenuating the signal power seen at the receiver. Strong destructive interference is frequently referred to as a deep fade and may result in temporary failure of communication due to a severe drop in the channel signal-to-noise ratio.
A common example of multipath fading is the experience of stopping at a traffic light and hearing an FM broadcast degenerate into static, while the signal is re-acquired if the vehicle moves only a fraction of a meter. The loss of the broadcast is caused by the vehicle stopping at a point where the signal experienced severe destructive interference. Cellular phones can also exhibit similar momentary fades.
Fading channel models are often used to model the effects of electromagnetic transmission of information over the air in cellular networks and broadcast communication. Fading channel models are also used in underwater acoustic communications to model the distortion caused by the water. Mathematically, fading is usually modeled as a time-varying random change in the amplitude and phase of the transmitted signal.
6. Fresnel Zone
Fig.2.4 Fresnel Clearance
The Fresnel zone or First Fresnel zone is a three dimensional elliptic shaped region surrounding the line of sight path from the transmitter to the receiver. If a reflective object is placed anywhere on the edge of the ellipse, it will cause a reflected signal that, due to propagation delay, is delayed 180 degrees (in carrier phase) with the line of sight signal at the receiving antenna. If the 29
Fresnel ellipse is cut perpendicular to the line of sight path anywhere along the line of sight path, a circle is formed with a radius known as the Fresnel radius. Note that Fresnel zones and Fresnel radius are frequency dependent because they are defined by the wavelength and propagation delay of the carrier.
The level of the resultant signal at the receiving antenna from the combining of the line of sight signal and a single reflected signal will vary from an increase of up to 3 dB in power (if they are in-phase) to a deep cancellation (out of phase). The total phase difference between the line of sight signal and the reflected signal at the Fresnel zone ellipse will be determined by both the 180 degree propagation delay and the phase shift at the point of reflection. If the wave is linearly polarized and hits a surface that is parallel to the wave’s polarization, a 180-degree shift will occur. If the surface is perpendicular to the wave’s polarization, a phase shift from 0 to 180 degree shift will occur depending on the angle of incidence.
Significant signal attenuation can also occur if objects are allowed within the first Fresnel zone. An object can attenuate or block the signal if it must go completely through it. Trees, rain or fog are examples of possible obstructions. Diffraction is another type of loss that occurs when a RF or microwave signal grazes the top of an object. A sharp surface will cause only minor losses up to 6 dB. However, a smooth rounded object like a bald mountaintop can cause sharp losses in excess of 30 dB.
Where: d1 = distance from one end of the path to the reflection point (km) d2 = distance from the other end of the path to the reflection point (km) 30
D = d1 + d2 f = frequency (GHz) n = number of Fresnel zone Fresnel zone clearance
Fig.2.5 Line of Sight Diagram
The concept of Fresnel zone clearance may be used to analyze interference by obstacles near the path of a radio beam. The first zone must be kept largely free from obstructions to avoid interfering with the radio reception. However, some obstruction of the Fresnel zones can often be tolerated, as a rule of thumb the maximum obstruction allowable is 40%, but the recommended obstruction is 20% or less.
7. Tropospheric Scatter System
Tropospheric Scatter System is the scattering of distant TV and FM radio stations by the troposphere so that they travel farther than the line of sight. This effect sometimes allows reception of stations up to a hundred miles away. The phenomenon has been used to build communication links in a number of parts of the world. Large billboard antennas focus a high power radio beam at the troposphere mid-way between the transmitter and receiver. A certain proportion of the signal is refracted and received at a similar antenna at the receiving station. One such link operated between the North of Scotland, at Mormond Hill 31
and the Shetland Isles.US Army TRC-170 Tropo Scatter Microwave System. The U.S. Army uses tactical tropospheric scatter systems developed by Raytheon for long haul communications. The systems come in two configurations, the original “heavy tropo”, and a newer “light tropo” configuration exist. The systems provide four multiplexed group channels and trunk encryption, and 16 or 32 local analog phone extensions.
8. Radio Equipment
As defined in Federal Information Management Regulations, any equipment or interconnected system or subsystem of equipment (both transmission and reception) that is used to communicate over a distance by modulating and radiating electromagnetic waves in space without artificial guide. This does not include such items as microwave, satellite, or cellular telephone equipment.
The two types of FM microwave equipment in common use are the IF heterodyne type and the base band, or re-modulating type. The IF heterodyne type, by eliminating demodulation and re-modulation steps at repeaters, contributes the least amount of distortion, and is the preferred choice for systems handling exclusively, or almost exclusively, long-haul traffic, with little or no requirement for drop and insert along the route. The heterodyne type is also preferable for systems carrying color TV, if more than a few hops are involved. Equipment of the base band or re-modulating type is widely used for short haul or for distributive systems in the telephone industry, and for either short or long haul industrial systems. The great flexibility for drop and insert, plus maintenance advantages, are the determining factors. Heterodyne systems are inherently at a considerable disadvantage in such applications.
9. Towers and Antenna Systems
Towers are tall man-made structures, always (and usually much) tall. Towers are generally built to take advantage of their height, and can stand alone or as part of a larger structure. Examples of the various uses of towers include:
To save ground-level space. To enhance views To increase strategic advantage To increase potential energy To enhance communications As support To access tall or high objects To access atmospheric conditions a loft To take advantage of the temperature gradient inherent in a height differential: To protect from exposure: For industrial production: To drop objects: To test height-intensive applications: To improve structural integrity: To mimic towers or provide height for training As art For recreation: As a symbol:
The term “tower” is also sometimes used to refer to firefighting equipment with an extremely tall ladder designed for use in firefighting/rescue operations involving high-rise buildings.
In electromagnetic and communications engineering, a waveguide is any physical structure which guides waves, such as electromagnetic waves, light, or sound waves. They are structures that guide electromagnetic waves, or, in some contexts, the term might refer specifically to hollow metallic or dielectric (nonoptical) waveguides, as described below. There are different types of waveguide for each type of wave.
The first waveguide was proposed by J. J. Thomson in 1893 and experimentally verified by O. J. Lodge in 1894. The mathematical analysis of the propagating modes within a hollow metal cylinder was first performed by Lord Rayleigh in 1897. (McLachan, 1947.)
1. Principles of Operation
Depending on the frequency, they could be constructed from either conductive or dielectric materials. Generally, the lower the frequency to be passed the larger the waveguide is. For example the natural waveguide the earth forms given by the dimensions between the conductive Ionosphere and the ground as well as the circumference at the median altitude of the earth are resonant at 7.83 Hz. This is also known as Schumann resonance. Waveguides can also be as small as a few centimeters. An example might be those that are used in Extremely high frequency (EHF) Satellite Communications (SATCOM). There is a formula for calculating waveguide dimensions, more information may be found at this website.
Electromagnetic waveguides are analyzed by solving Maxwell’s equations, or their reduced form, the electromagnetic wave equation, with 34 boundary conditions determined by the properties of the materials and their interfaces. These equations have multiple solutions, or modes, which are eigen functions of the equation system. Each mode is therefore characterized by an eigen value, which corresponds to the axial propagation velocity of the wave in the guide. Waveguide propagation modes depend on the operating wavelength and polarization and the shape and size of the guide. The longitudinal mode of a waveguide is a particular standing wave pattern formed by waves confined in the cavity. The transverse modes are classified into different types:
TE modes (Transverse Electric) have no electric field in the direction of propagation. TM modes (Transverse Magnetic) have no magnetic field in the
direction of propagation. TEM modes (Transverse Electromagnetic) have neither electric nor magnetic field in the direction of propagation. Hybrid modes are those which have both electric and magnetic field components in the direction of propagation.
In hollow metallic waveguides, the fundamental modes are derived from the transverse electric TE1, 0 mode for rectangular and TE1, 1 for circular waveguides.
3. Hollow Metallic Waveguides
In the microwave region of the electromagnetic spectrum, a waveguide normally consists of a hollow metallic conductor. Hollow waveguides must be one-half wavelength or more in diameter in order to support one or more transverse wave modes.
In some waveguides, there may be a positive gas pressure internally present, allowing for the detection of potentially dangerous RF leaks. Another 35
solution to detect RF leakage of a waveguide is to have a partial vacuum present inside. Then leaks can be detected in basically the same way.
A slotted waveguide is generally used for radar and other similar applications. The waveguide structure has the capability of confining and supporting the energy of an electromagnetic wave to a specific relatively narrow and controllable path.
A closed waveguide is an electromagnetic waveguide (a) that is tubular, usually with a circular or rectangular cross section, (b) that has electrically conducting walls, (c) that may be hollow or filled with a dielectric material, (d) that can support a large number of discrete propagating modes, though only a few may be practical, (e) in which each discrete mode defines the propagation constant for that mode, (f) in which the field at any point is describable in terms of the supported modes, (g) in which there is no radiation field, and (h) in which discontinuities and
bends cause mode conversion but not radiation.
Hollow metallic waveguides are far narrower than the wavelength of operation. They can take the form of single conductors with or without a dielectric coating, e.g. the Goubou line and helical waveguides.
Dielectric rod waveguides, in linear arrays of short transverse conductors, and planar resistive conductors use the same principle as optical waveguides.
These function via a refractive index effect where the waveguide slows the EM wave velocity below the free space velocity, continuously bending the relatively wide EM wave fronts towards the narrow waveguide and keeping them entrained. Helical waveguides and linear arrays of short conductors are used as part of “endfire” antennas such as the helical antenna and Yagi antenna. Planar resistive waveguides are used in Over-The-Horizon radar and the Ground Wave Emergency Network, where the resistive surface of the Earth or ocean serves to 36
slow the waves below free space velocity; entraining them and forcing them to follow the curvature of the Earth. Several waveguides based on entrainment of EM waves also exist.
Waveguides can be constructed to carry waves over a wide portion of the electromagnetic spectrum, but are especially useful in the microwave and optical frequency ranges. Waveguides are used for transferring both power and communication signals.
Waveguides used at optical frequencies are typically dielectric waveguides, structures in which a dielectric material with high permittivity, and thus high index of refraction, is surrounded by a material with lower permittivity. The structure guides optical waves by total internal
reflection. The most common optical waveguide is optical fiber.
electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber and rectangular waveguides.
Optical waveguides are used as components in integrated optical circuits or as the transmission medium in local and long haul optical communication systems. Optical waveguides can be classified according to their geometry (planar, strip, or fiber waveguides), mode structure (singlemode, multi-mode), refractive index distribution (step or gradient index), and material (glass, polymer, semiconductor).
Dielectric Slab Waveguide
A dielectric slab waveguide consists of three dielectric layers with different refractive indices.
Practical rectangular-geometry optical waveguides are most easily understood as variants of the simple dielectric slab waveguide. The slab waveguide consists of three layers of materials with different dielectric constants, extending infinitely in the directions parallel to their interfaces.
Light may be confined in the middle layer by total internal reflection. This occurs when the angle of incidence between the propagation direction of the light and the normal or perpendicular direction, to the material interface is greater than the critical angle. The critical angle depends on the index of refraction of the materials, which may vary depending on the wavelength of the light.
This structure confines electromagnetic waves only in one direction, and therefore it has little practical application. Structures that may be approximated as slab waveguides do, however, sometimes occur as incidental structures in other devices.
Fig. 2.6 Rectangular Wave Guides
Rectangular optical waveguide is formed when the guiding layer of the slab waveguide is restricted in both transverse directions rather than just one. Rectangular waveguides are used in integrated optical circuits, and in laser diodes. They are commonly used as the basis of such optical components as Mach-Zehnder interferometers and wavelength division multiplexers. The cavities of laser diodes are frequently constructed as rectangular optical waveguides. Optical waveguides with rectangular geometry are produced by a variety of means, usually by a planar process. The field distribution in rectangular waveguide cannot be solved analytically, however approximate solution methods, such as Marcatili’s method, are known.
11. Terrain/Humidity Factor
Propagation of microwave energy is affected by obstacles placed in its path. The shape and material content of any obstruction must be taken into account when surveying a microwave path. Terrain such as mountains, hills, trees and buildings can block a microwave signal and limit the distance of a microwave path. However, a bird or other object moving through the microwave path will not affect your design because transmission can go around a small, intermittent object.
12. Climate Factor
The climate of any particular place is influenced by a host of interacting factors. These include latitude, elevation, nearby water, ocean currents, topography, vegetation, and prevailing winds. The global climate system and any changes that occur within it also influence local climate. Consider how each factor illustrated by the thumbnail images might control climate at your location. a. Latitude – usually denoted symbolically by the Greek letter phi (Φ) gives the location of a place on Earth (or other planetary body) north or south of the 39
equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps. Technically, latitude is an angular measurement in degrees (marked with °) ranging from 0° at the equator (low latitude) to 90° at the poles (90° N for the North Pole or 90° S for the South Pole; high latitude). The complementary angle of latitude is called the co-latitude.
b. Elevation – The elevation of a geographic location is its height above a fixed reference point, often the mean sea level. Elevation, or geometric height, is mainly used when referring to points on the Earth’s surface, while altitude or geo-potential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit. Less commonly, elevation is measured using the center of the Earth as the reference point.
Due to equatorial bulge, there is debate whether the summits of Mt. Everest or Chimborazo are at the higher elevation, as the Chimborazo summit is further from the Earth’s center while the Mt. Everest summit is higher above mean sea level.
c. Nearby water, ocean currents- An ocean current is continuous, directed movement of ocean water. Ocean currents are rivers of hot or cold water within the ocean. The currents are generated from the forces acting upon the water like the planet rotation, the wind, the temperature and salinity differences and the gravitation of the moon. The depth contours, the shoreline and other currents influence the current’s direction and strength.
d. Topography – (topo, “place”, and graphia, “writing”) is the study of Earth’s surface features or those of planets, moons, and asteroids. In a broader sense, topography is concerned with local detail in general, including not only relief but also vegetative and human-made features, and even local history and culture. This meaning is less common in America, where topographic maps with elevation contours have made “topography” synonymous with relief. The older sense of topography as the study of place still has currency in Europe. 40
For the purposes of this article, topography specifically involves the recording of relief or terrain, the three-dimensional quality of the surface, and the identification of specific landforms. This is also known as
geomorphometry. In modern usage, this involves generation of elevation data in electronic form. It is often considered to include the graphic representation of the landform on a map by a variety of techniques, including contour lines, Hypsometric tints, and relief shading.
e. Vegetation – is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader than the term flora which refers exclusively to species composition.
Perhaps the closest synonym is plant community, but vegetation can, and often does, refer to a wider range of spatial scales than that term does, including scales as large as the global. Primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, 39 roadside weed patches, wheat fields, cultivated gardens and lawns; all are encompassed by the term vegetation.
f. Prevailing winds- The prevailing winds are the trends in speed and direction of wind over a particular point on the earth’s surface. A region’s prevailing winds often show global patterns of movement in the earth’s atmosphere. Prevailing winds are the causes of waves as they push the ocean.
In general, reliability (systemic def.) is the ability of a person or system to perform and maintain its functions in routine circumstances, as well as hostile or unexpected circumstances.
The IEEE defines it as “. . . the ability of a system or component to perform its required functions under stated conditions for a specified period of time.
CHAPTER III DESIGN METHODOLOGY
A. Site Selection
The selection of sites for the transceivers must be considered in designing a point-to-point microwave communication system.
The proponents had chosen the municipalities of Panabo and Kapalong where to construct the communication system. After selecting the site based on their standards, the topographical map of the selected municipalities was purchased. Some factors are to be considered like obstructions and terrains which might attenuate the signal. These obstructions and loss terrains should be avoided.
Moreover, they also considered the required distance between the two sites which will not be less than 30 kilometers. The topographical map with 1:50,000 scale show the approximate total area and obstructions of the locations.
Davao del Norte and once known simply as Davao, is a province of the Philippines located in the Davao Region in Mindanao. Its capital city is Tagum City. It borders the province of Agusan del Sur to the north, Bukidnon to the west, Compostela Valley to the east, and the city of Davao to the south. Davao also includes Samal Island to the south in the Davao Gulf. The province of Compostela Valley used to be part of Davao until it was made into an independent province.
Panabo City is near Davao City in the province of Davao del Norte, Philippines. The city has an area of 249 square kilometers.
Kapalong is municipality in the province of Davao del Norte, Philippines. According to the census, it has a population of 68,593 people in 13,843 households.
Panabo is known as the “Banana Capital of the Philippines” due to numerous banana plantations scattered throughout the city. In fact, Panabo is the home of the world’s biggest banana plantation, which is owned by the Tagum Agricultural Development Company (TADECO), which covers around 6,900 hectares of banana fields and produce millions of boxes of export-quality bananas annually. The city itself cultivated 40% of its land or around 10,000 hectares into planting export-quality bananas, which is better known as “Cavendish Bananas”. Thus, banana cultivation and exportation are the main economic lifeblood of the city.
In Kapalong you’ll have to go about thirty miles north of Davao City to find caves to explore, but spelunkers say the trip is worth it. The town of Kapalong stands next to the Suaon Natures Park, a series of caves where limestone plus water plus time have led to a proliferation of intricate mineral formations. Okbot, Otso, and Alena Cave are open to the public, as is Sua-On Underground River.
Panabo del Norte, Region 11, Philippines, its Geographical coordinates are 7° 18’ 29‖ North, 125° 41’ 3‖ East and has a total of 251.23 km2 or 97.00 sq. mi.
Kapalong is one of the oldest towns in Davao del Norte Province. It has coordinates of 7°45’ N, 125°30’ E. It is politically subdivided into 14 barangays.
Long before the rich lowland was discovered by civilization, a group of stocky-haired aborigines called Aetas have already staked a claim and declared this place their own. Far from being civilized, these people led nomadic life and co-existed with the living creatures of the wilds. They have few wants and were easily satisfied. With the use of their bow and arrow “pana-sa-boboy” as they call it – they hunted for food which primarily consisted of rootcrops and meat of wild boars. “Pana-Sa-Boboy” was their most essential tool and it became part of their life.
Even the Christian settlers came at the onset of the century, the place was already a thriving trading community; thus, the place was already knwn as Taboan, which means “trading center”. After the Cristian settlers began pioneering the region, these friendly natives moved further to the hinterlands along with them their “pana-sa-boboy”. These later evolved into present day name Panabo. Political Subdivision
Panabo is politically subdivided into 40 barangays namely:
A. O. Floirendo
San Francisco (Pob.) San Nicolas San Roque San Vicente Sta Cruz Sto Niño (Pob.)
Datu Abdul Dadia Buenavista Cacao Cagangohan Consolacion
Lower Panaga (Roxas) Mabunao Maduao Malativas Manay
Dapco Gredu (Pob.) J.P. Laurel Kasilak Katipunan Katualan Kauswagan
Nanyo New Malaga (Dalisay) New Malitbog New Pandan (Pob. New Visayas Quezon Salvacion
Sindaton Tagpore Tibungol Upper Licanan Waterfall San Pedro
Panabo, in 1949, is converted into cities almost 50 years later. Though the town of Talaingod emerged from the town in 1991, it is still the largest town by land area in the province of Davao Del Norte.
The Kapalong was founded in July 8, 1948 from the Municipal District of Tagum, which was formed in 1918. It was one of the oldest towns in Davao del Norte Province, others being Tagum, in 1941;
Kapalong is politically subdivided into 14 barangays namely: Semong, Florida, Gabuyan, Gupitan, Capungagan, Katipunan,Luna, Mabantao, Mamacao, Pag-asa, Maniki (Poblacion), Sampao,Sua-on and Tiburcia,
5. Population, People and Culture
Davao del Sur is an ethnic mix of Mindanaoans, Visayans, Tagalogs, Chinese, Japanese and Spanish with a number of indigenous tribes scattered in more than 2,300,000 inhabitants spread across a vast 244,000-hectare land. Davaoeño, a variant of Cebuano, is the main and official language of the province, although English and Filipino are widely spoken. It is the third largest city in the Philippines according to population. 46
Aita people live in some areas of Davao City all the way to Davao del Norte, Compostela Valley and Bukidnon. They are related to the Manobos of Cotabato and include sub-groups such as the Talaingod of the Kapalong forests in Davao del Norte and the Matigsalug. Numbering about 222,000, Ata men wear long-sleeved shirts, carry spears, hunt, and log and grow crops. Their womenfolk wear native blouses, “malong” skirts and accessories of brass bracelets and bead necklaces.Mandaya and Mansaka are culturally related groups who are highly musical – playing the five string bamboo guitars, two-string lute, violin, flute, gong, drum and bamboo Jew’s harp. They are also excellent silversmiths crafting breastplates, jewellery, daggers and knives. The Mandayas are famous for their colorful abaca fiber weaves embroidered with tribal motifs.
In both groups, women generally wear handwoven abaca tube skirts, embroidered blue cotton tops and heavy jewellery. Men sport wide blue or white fringed and embroidered trousers and a loose shirt. Red is a color only for a headman (“bagani”) and for women of high status.
Bagobos live in an area that extends from Davao del Sur and South Cotabato to the foot of Mt. Apo and Davao City all the way to the land bordered by the Davao and Pulangi rivers and up to northern Cotobato and southeast Bukidnon. Numbering about 80,000, their traditional costume is woven from abaca fiber and heavily ornamented with beads, shells, metal discs, embroidery and brightly-colored geometric applique. Though Bagobos have the most stunning costumes among the Davao ethnic groups, they wear them only on special occasions. Like the Mandayas and Mansakas, they shave their eyebrows to a thin line and file and blacken their teeth. Bagobo smiths cast little bells which are attached to pouches, bracelets, jackets, anklets and inlaid metal boxes.
Tagacaolos number about 23,000 and occupy the area between the western shores of the gulf and the slopes of Mt. Apo. This is one of the tribes which resisted Muslim conversion and maintained a highland animistic culture.
Kalagans are a Muslim group related to the Tagacaolos. Numbering only about 7,000, they live along the shores of the Davao Gulf.
Mangguangans are now only 3,000. They can be found in Davao del Sur and Davao
Panagtagbu Festival (first week of March; Tagum)
Coincides with the city of Tagum’s founding anniversary. It aptly describes a celebration in the city where Tagumeños met Tagumeños from all walks of life in one occasion and setting since the city of Tagum is a crossroad business center in the northern part of Southern Mindanao.
Pangapog Festival (first week of August; Island Garden City of Samal)
A thanksgiving festival celebrating bountiful harvest which features parade, indak-indak sa dalan (streetdancing), cultural presentation, and agriindustrial fair.
Banana Festival (first week of July)
Celebrated in time for the founding anniversary of the province. The festival pays tribute to the largest economic contributor and the province’s number one export – bananas. 48
Andaon Festival (Dibabawon Community Festival – first week of September; Kapalong)
It is a gathering, celebration, and thanksgiving to Tagihinit (God) for the good harvest, good health, and good future for all the people.
Majority of the people in Davao speak the English language, even fluently. In fact, English is the medium of instruction in schools. This is among reasons why many foreigners have settled in the province. Conversing with the people in any language becomes easy eventually due to the peoples easy absorption of any language and culture. The same goes to every Filipino on a larger scale.
In fact, a lot of local languages or dialects are spoken in Davao. Almost any dialect or language from the upper most part of the archipelago down to Mindanao may be heard being in use in Davao. But most people say the dominant dialect is Cebuano, followed by Filipino or Tagalog, the more archaic form of the native language. Some say English comes third.
According to official records of the national census, about 74 percent of the population speaks fluent Cebuano. Tagalog is spoken by about 3 percent of them. The next often used dialect is Hiligaynon, then Bagoboo, and then Davaoeno. Ilocano (a dialect from northern Luzon) is also used followed by Waray, a Visayan dialect.
7. Commerce and Industry
Agriculture is the main industry of the people in the region and because of its thickly forested area, wood processing is one of the major industries. Forested areas are fully developed for large scale operators. The Region at present is the biggest producer of lumber in the country.
Grain processing is another major industry of the region brought about by large industries of the rice and corn from Davao del Sur and South Cotabato. Large quantities of export quality fruits like pineapples, bananas and citrus are also produced in the region.
Fishing is the industry mostly engaged in especially in Surigao del Sur. It is the main livelihood of the people. The region being surrounded by large bodies of water is rich with fish resources.
The region, particularly Davao Province, has rich gold and copper deposits. Iron, are and copper are mined in Mati, Davao, and Oriental.
Purported to be the banana capital of Davao del Norte, Panabo cultivated 40% of its land or around 10,000 hectares into planting export-quality bananas, which is better known as Cavendish Bananas.
The Cavendish Banana is recognized around the world as one of the most nutritious tropical fruit, which is high in potassium, fiber, manganese and Vitamin C and B6. The Japanese right now are going crazy over bananas that they even established and published a Morning Diet out of it. In fact, Panabo is the home of the world’s biggest banana plantation, which is owned by the Tagum Agricultural Development Company. TADECO
covers around 6,900 hectares of banana fields and produce millions of boxes of export-quality bananas annually. Aside from Cavendish bananas, Panabo is also known as the home of the finest bangus in Mindanao.
With only three years in existence, the Panabo Bangus have reached as far as Mati and General Santos City. According to National Director Malcolm Sarmiento of the Bureau of Fisheries and Aquatic Resources, the Panabo bangus is the tastiest bangus that he has encountered in the Philippines.
This bangus has been bred in more than 200 fish cages spread out in the 1,075-hectare Panabo Mariculture Park.
Located in Barangay Sampao, Kapalong town, the cooperative took off from its members who were once plantation workers, to the current status as members of the cooperatives and co-owners of the land they are tilling, awarded to them under the Comprehensive Agrarian Reform Program.
From getting its main income from export receipts, the cooperative ventured into the production of flour from banana, and the use of their manufactured organic fertilizers.
Four years ago, the coop has put up its own Banana Flour Livelihood Center where its food grade banana flour is being processed and packed with high quality and safety, best for cakes and pastries.
AMSEFFPCO has also developed the bio-organic fertilizer from the wastes of the banana flour production that collects an average volume of three tons of banana peelings and stalks per day.
9. Topography and Climate
The province is composed of sandy beaches and outlying islands; agricultural plains and valleys; rainforests; swamps; rolling hills and mountains including the Philippines’ highest peak, Mt. Apo (3,144 meters).
Davao del Sur enjoys a mild, pleasant climate all year round. Because of its topographical characteristics and geographical location, it is rarely visited by typhoons. There is no pronounced wet or dry season. The coolest months are from November to February with an average temperature of 25 degrees Celsius. during the peak summer months from March to May, temperatures average 28 degrees Celsius but may rise as high as 32 degrees.
10. Infrastructure and Destinations
Pearl Farm Beach Resort. The Pearl Farm is located on Samal Island just a short boat ride from Davao City. The 11-hectare resort was once a real pearl farm that cultivated oysters imported from the Sulu Sea, and produces some of the best pearls in the country. Now the white sand beach resort is a top tourist attraction in Davao del Norte with cottages inspired by Isamal native design. Playa azalea beach resort in island garden city of samal banana beach resort in tagum city Tagum city hall is one of the bests landmarks in DAvao del norte .
In Panabo City a better road in Barangay means saving farmers from the difficulty of bringing farm products to market. This pushed the Local Government of Panabo, led by Mayor Jose L. Silvosa, Sr. to invest and partner with the Department of Agriculture – Mindanao Rural Development Program (DA-MRDP) for rehabilitating of 2.2 kilometers road with bridge component connecting between Barangay Buenavista and Barangay Waterfall in Panabo City. 52
During the groundbreaking last July 30, 2012 at Barangay Buenavista, Mayor Jose L. Silvosa, Sr. expressed his views on the advantages of having a favorable road network connecting to the nearby market and town proper.
The MinDA board noted that construction of the Kapalong-TalaingodValencia road, which covers 128.16 kilometers, has been ongoing since 2007 but work on the remaining portion may be hampered owing to lack of funding.
The Kapalong-Talaingod-Valencia road has been converted into a national road but it has not been allocated a budget in the 2011 General Appropriations Act.
Its completion will open the Tagum City-Valencia City direct route, an alternate to Davao City-Bukidnon via Buda route.
B. Radio Path Profiling In conducting the microwave system design, radio path profiling plays a very significant role. By this method, different transmission parameters can be determined. Since obstructions must be considered, this will contribute very much to the losses and will affect the height of the towers. Hence, these obstructions must be noted as references in calculating possible height and diameter of the antennas that will be using. These data are to be tabulated and graphed. These obstructions consist mostly of mountains and other land formations that may affect in the design of the system. These obstructions are carefully analyzed for the reliability of the desired microwave communication.
C. Transmission Calculations
One of the major constraints in considering in the design of a microwave communication system is the calculation of the important parameters that will 53 determine the physical as well as technical aspects of the design. By using the derived formulas 52 from theories of Wireless Communication, these parameters can be obtained. The preliminary parameter that is to be determined in the design is the operating frequency. And from this factor, the other important parameters can be calculated such as the Fresnel zone, system gains losses, height of the parabolas, towers and obstructions, height due to k curve, waveguides, fade margin, and the parabola diameter. Then tabulation of the following data must to be summarized. While other numerical figures base on calculated data were obtained from Andrew Catalogue, it also includes the types and specifications of the parabolic antennas and other materials are to be used.
CHAPTER IV PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA
A. Site Selection
Factors must be considered in designing a microwave system. Some of these are the distance between the two sites ranges which will not be less than 35 kilometers, obstructions, influence of weather, elevation of each site, amount of leveling required and access to road transportation, power generation facility and telephone communication.
After the consideration of the said factors, the researchers have selected the sites inPanabo, Davao del Norte, and Kapalong, Davao del Norte. It has a path length of 38.463 kilometers which satisfies the required path length that is not less than 35 kilometers. Site A has an elevation of 13.106 meters and Site B has an elevation of 19.202 meters.
B. Path Calculation
From the CCIR Recommendation 384-4, the preferred radio frequency channel arrangement for up to 8 go and return channels, and operating at frequencies in the 6 GHz band, was derived using the formula: Lower half of the band: fn = fo – 350 + 40n Upper half of the band: f’n= fo – 10 + 40n where:
(eq. 4.1-a) (eq. 4.1-b)
fo = the center frequency (MHz) at the center band occupied which is 6770 MHz
fn = the center frequency (MHz) of one radio frequency channel in the lower half of the band f’n = the center frequency (MHz) of the radio frequency channel in the upper half of the band n = radio frequency channel 1,2,3,4,5,6,7 or 8
The chosen n is equal to channel 8 Upper half of the band: f’n = 6770 – 10 + 40(8) = 7.08 GHz
C. Topographical Site of the Map
Subsequent to considering those conditions and factors mentioned above, the proponents come out with the following sites and their parameters:
Table 4.1. The Sites and Necessary Parameters Site A Site B Elevation of Site A (Ea) Elevation of Site B (Eb) Path Length (D) Elevation of Highest Obstruction (E) Distance from Site A to Highest Obstruction (d1) Distance from Site B to Highest Obstruction (d2) Scale Used 1. Fresnel Zone Panabong, Davao del Norte Kapalong, Davao del Norte 13.106 meters 19.202meters 38.463 kilometers 25.603 meters 30.417 kilometers 8.047 kilometers 1:50,000
The first Fresnel zone at any point of the path can be calculated via the formula: ( )( )√ (eq. 4.2)
F1 F d1 d2 f
= first Fresnel zone radius in meters = Fresnel zone radius in meters = distance from site A to the highest obstruction in kilometers = distance from site B to the highest obstruction in kilometers = operational frequency in GHz
considering the highest obstruction (25.6032):
( )√ (
2. Height due to k-curve
The curve for various values of K can be calculated from the relationship:
= change in vertical distance from a horizontal reference line in meters
d1 d2 k
= distance from site A to point of obstruction = distance from site B to point of obstruction = the equivalent earth radius factor (4/3) 57
Considering highest obstruction: ( )( ( ) )
3. Total Elevation of Obstruction:
TEO = Height of highest obstruction + height due to k-curve + tree clearance + Fresnel Zone
Highest Obstruction: Calculated height due to k-curve: Tree clearance: Fresnel clearance: TEO
25.603 m 14.398m 10 m 9.841 m 59.842. m
4. Parabola Height
E a Eb Hp = TEO – Eb – d2 D
Hp Ea E d2 D
= parabola height in meters
TEO = total elevation of obstruction in meters = elevation of site A in meters = elevation of site B in meters = distance from site B to the highest obstruction in kilometers = distance from site A to B in kilometres 58
5. Free-Space Loss
FSL = 92.4 + 20 log fGhz +20 log Dkm where:
= frequency in GHz = distance in kilometres
FSL 92.4 20log 7.08 20log 38.463
FSL = 141.1016 dB
6. Waveguide length
For Rigid Waveguide (LRW)
LRW = parabola ht. + ½ parabola diameter + 6.10 m
For Site A:
LRW 41.915m 0.5B 6.10m
LRW (48.015 0.5B)m
For Site B:
LRW 41.915m 0.5B 6.10m
LRW (48.015 0.5B)m
For Flexible Waveguide (LFW)
The assumed allowances for the flexible waveguides are as follows: 59
For Site A: For Site B:
LFW =10 ft = 3.048 m LFW =10 ft = 3.048 m
7. Waveguide Loss
WR 137 is used as rigid and flexible wave guides. The WR 137 rigid wave guide has an attenuation of 5.8 dB/ 100 m and the flexible waveguide has an attenuation of 0.3 dB/m.
WGloss = RWGloss + FWGloss
For Rigid Waveguide
RWGloss = LRW * attenuation
(eq. 4.7- a)
For Flexible Waveguide
FWGloss = LFW * attenuation where:
(eq. 4.7- b)
WGloss LRW LFW RWGloss FWGloss
= waveguide loss = length of rigid waveguide = length of flexible waveguide = rigid waveguide loss = flexible waveguide
For rigid waveguide attenuation,
48.015 0.5B m5.8dB/100m
RWGloss = (2.785 + 0.029) dB For sites A & B RWGlossA = RWGlossB
For flexible waveguide attenuation,
For sites a & B FWGlossA = FWGlossB then, WGloss = (2.785+ 0.029B + 0.9144) dB WGloss = (3.699+ 0.029B) dB WGlossA = WGlossB 8. Total Fixed Loss
TFL = WGloss + connector loss + radome loss + circular loss Therefore,
TFLA= (3.699+ 0.029B)B + 0.5dB + 0.5 dB + 0 dB TFLA = (4.699+ 0.029B) dB TFLA = TFLB 9. Total Loss TL = FSL + TFLA + TFLB (eq. 4.9) 61
TL = 141.1015 dB + (4.699+ 0.029B) dB + (4.699+ 0.029B) dB TL = (150.5 + 0.029B) dB
10. Fade Margin
U 1 %reliabilit y ndp U 1 99.9999% ndp
U 110 6 ndp
R = system reliability a = Surface factor = 4.0, for very smooth terrain, over water, desert = 1.0, for average terrain with some roughness = 0.25, for mountainous, very rough, or very dry terrain b = climate factor = 0.5, for hot, humid coastal areas = 0.25, for normal, interior temperature = 0.125, for mountainous or very dry but not reflective terrain
U abf 1.5 D 3 3 10 7 10 FM / 10 ndp
10 FM / 10
abf D 3 3 10 7
FM 10log U log a log b 1.5 log f 3 log D log 3 10 7 ndp
FM 10log(1×10 6 ) log( 0.25) log( 0.25) 1.5 log( 7.08) 3 log( 38.463) log 3×10 7
FM = 43.032 dB
11. Parabola Diameter From the technical specification of TRP – 6 GIC140 MB – 700AA: Instruction Manual vol.1, NEC Corporation
Transmitter output power = 30 dBm Practical threshold = -78 dBm Received signal level = -34 dBm
Using the formulas for computing the total gain, Total Gain = RSL – Transmitter Output Power + Total Loss
RSL = Received Signal Level = FM + Practical Threshold Total Gain = Transmitter Gain + Receiver Gain
(eq. 4.12) (eq. 4.13)
RSL = 43.032 dB + (-78 dBm) = -34.968 dBm Total Gain = -34.968 dBm – 30 dBm +
(150.5+ 0.029B) Total Gain = 85.532 + 0.029B equation 1
Total Gain = 2(Antenna Gain)
Antenna Gain = 20logf + 20logB + 17.8
2*(Antenna Gain) = 2(20logf + 20logB + 17.8) = 2[20log (7.08GHz) + 20logB + 17.8] 2*(Antenna Gain) = 69.6013 + 40logB equation 2
Equating 1 and 2:
Total Gain = 2*(Antenna Gain) 85.532 + 0.029B = 69.6013 + 40logB 40logB – 0.029B= 15.9307 B = 2.51
Using interpolation method, If B=2.5, the left side of the equation will yield 15.845 to the right side. If B=3, the left side of the equation will yield 18.998 to right side.
The available antenna diameter next to the computed value of B is 3 m. However, if the antenna diameter will be used, the value of RSL would be RSL = 2(20logf + 20logB + 17.8) + PTransmitter – Total Loss = 2[20log (7.08GHz) + 20log (3) + 17.8] + 30 –150.5 – 0.029(3) RSL = -32.9dBm
The value of RSL obtained is higher than the required value of RSL (-34 dBm)
according to the NEC transceiver specifications which was made clear prior to the calculations, therefore, the antenna diameter to be used is 1.8 meters.
Having obtained the appropriate antenna diameter, unknown values from the previous sections can now be obtained.
Using B = 3 m:
Length of Rigid Waveguide LRW A = LRWB = 48.015 + .5(3 )= 49.515 dB Rigid Waveguide Loss RWGLossA = RWGLossB = 2.785 + 0.029(3) = 2.872dB Waveguide Loss WGLossA= WGLossB = 3.699+ 0.029(3) dB = 3.786dB Total Fixed Loss TFLA= TFLB = 4.699+ 0.029(3) dB = 4.786 dB Total System Loss Total Loss = 150.5 + 0.029(3) = 150.587 dB
Total System Gain Total Gain = 2[20log (7.08GHz) + 20log (3m) + 17.8] Total Gain= 88.686dB
12. Radio and Data Path Profile
The Data Path Profile had been completed after appropriate locations have been selected from the topographical maps. The different terrain and obstacles such as buildings, mountains and other obstacles have a great influence in the microwave beam, thus proper consideration must be emphasized.
There are some basic parameters required in making the path profile; these include curvature of the earth, the Fresnel zones and equivalent earth profiles.
From the Data Path Profile, after getting the possible obstruction distances with respect to the two sides, we determine the factor that could affect the transmission signal. These led to the determination of the total elevation of obstruction. Then, by adding the obstruction elevation, earth curvature, Fresnel zone and the tree allowance, which is 10 meters, the group came up with the actual height of the highest possible obstruction which is 59.98845 meters. After getting the total elevation of the obstruction, the group computed the parabolic height and we came up with a value 48.475 meters.
Table 4.1 Data Path Profile
elevation (m) 13.10640 10.05840 5.79120 7.62000 10.05840 12.19200 10.05840 13.10640 10.97280 17.98320 d1 (in km) 0.00000 0.57272 1.19091 2.02777 2.70370 3.25087 3.58884 4.05555 4.57054 4.95678 d2 (in km) 38.46332 37.89060 37.27241 36.43555 35.75962 35.21245 34.87448 34.40777 33.89278 33.50654 K-curve (m) 0.00000 1.27651 2.61107 4.34606 5.68725 6.73360 7.36228 8.20837 9.11225 9.76968 Fresnel Clearance (in meters) 0.00000 2.97405 4.25350 5.48763 6.27752 6.83063 7.14238 7.54163 7.94602 8.22767 Tree Allowance (in meters) 0.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 TEO (m) 13.10640 24.30896 22.65577 27.45369 32.02316 35.75623 34.56307 38.85640 38.03107 45.98055 66
12.80160 18.89760 17.67840 18.89760 18.89760 10.05840 16.45920 7.01040 5.48640 6.70560 3.96240 5.18160 3.35280 2.74320 8.83920 8.22960 7.92480 7.62000 6.70560 10.97280 8.22960 10.05840 11.88720 13.71600 15.24000 17.67840 19.20240 21.33600 23.46960 25.60320 22.55520 22.25040 22.55520 21.94560 23.46960 21.33600 21.03120 19.81200 19.20240
5.45568 6.00285 6.75924 7.20986 7.67657 8.12719 8.36859 8.81921 9.39857 9.78481 10.12277 11.07229 12.07008 12.55288 13.35756 14.27488 15.16002 16.09344 18.18559 19.95587 20.76054 22.20895 23.17455 24.14016 25.10577 26.23231 27.03698 28.16352 29.29006 30.41660 31.38221 31.70408 32.18688 32.83062 34.43996 35.24463 36.21024 37.33678 38.46332
33.00765 32.46047 31.70408 31.25346 30.78675 30.33613 30.09473 29.64412 29.06475 28.67851 28.34055 27.39103 26.39324 25.91044 25.10577 24.18844 23.30330 22.36988 20.27773 18.50746 17.70278 16.25437 15.28877 14.32316
13.35756 12.23101 11.42634 10.29980 9.17326 8.04672 7.08111 6.75924 6.27644 5.63270 4.02336 3.21869 2.25308 1.12654 0.00000
10.59288 11.46208 12.60562 13.25489 13.90216 14.50279 14.81473 15.37868 16.06865 16.50670 16.87559 17.84008 18.73933 19.13239 19.72657 20.31101 20.78109 21.17696 21.69191 21.72543 21.61878 21.23486 20.84179 20.33902 19.72657 18.87340 18.17258 17.06345 15.80502 14.39729 13.07182 12.60562 11.88347 10.87795 8.15084 6.67303 4.79910 2.47420 0.00000
8.56730 8.91186 9.34585 9.58351 9.81472 10.02450 10.13173 10.32277 10.55180 10.69466 10.81350 11.11822 11.39498 11.51387 11.69129 11.86322 11.99971 12.11347 12.25986 12.26933 12.23918 12.13002 12.01723 11.87140 11.69129 11.43567 11.22135 10.87352 10.46488 9.98797 9.51710 9.34585 9.07420 8.68181 7.51516 6.79983 5.76656 4.14051 0.00000
10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000 10.00000
41.96178 49.27155 49.62988 51.73600 52.61448 44.58569 51.40566 42.71185 42.10685 43.90695 41.65148 44.13990 43.48711 43.38947 50.25706 50.40382 50.70560 50.91043 50.65738 54.96756 52.08756 53.42327 54.74621 55.92642 56.65786 57.98747 58.59632 59.27297 59.73950 59.98845 55.14413 54.20188 53.51288 51.50536 49.13560 44.80886 41.59685 36.42671 29.20240
Table 4.1, after the potential obstructions were determined; the highest elevation of obstacle is 25.60320 m and is approximate 30.41660 km away from Site A. The total elevation of the said obstruction was obtained by adding the height due to earth’s curvature, Fresnel clearance and tree allowance to the actual height of the obstruction and it yields to 59.98845
The elevations of Site A and Site B are 13.10640 m and 19.20240 m respectively. The connection between these two sites signifies the signal path. It can be observed from the link drawn that the signal may be attenuated at 30.41660 km away from Site A as discussed in the preceding paragraph. To achieve line of sight and to avoid such attenuation the suitable height of the antenna must be determined. The computed parabola height was 41.915 m for both sides.
35 30 Elevation (m) 25 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45 Distance (km)
Figure 1. Total Elevation of Obstruction versus Distance
Line of sight propagation can be achieved if the displacement between the transmitter and receiver antennas clears all the Total Elevation of Obstructions. The computation for the TEO’s is designed so that the output value provides sufficient allowance to minimize losses. As shown in Figure 1, the highest obstruction was not clearly passed so Line of Sight is not possible. Instead of using the parabola height of 41.915 meters, we decided to use 43 meters. 68
D. Transmission Calculations
The data path sheet arrangement is a vital instrument for future reference. It is a preliminary tool that gives a proper and formal way of determining and listing all the required parameters that affect the overall transmission loss equations. These equations are important in order to visualize the losses, which in other way have a dominant effect in the system. The calculations and parameters are for the individual paths and do not reflect the overall system.
Item 1: Site Location The site location can be described by geographical coordinates, political subdivision, access road and physical terrain or object which can be identified with.
Site A: Panabo, Davao del Norte Site B: Kapalong, Davao del Norte
Item 2: Latitude
The latitude of a place on earth is its angular distance from the equator measured along the meridian through the place. Site A: 7°26’38.02‖ N Site B: 7°37’46.81‖ N
Item 3: Longitude
The longitude of a place on earth is the angle at either pole between n the meridian passing through the point and the prime meridian.
Site A: 125°46’35.84″E
Site B: 125°43’03.52”E
Item 4: Site Elevation
The site elevation is the mean sea level elevation of the site at the actual lower location.
Site A: 13.10640 m Site B: 19.20240 m
Item 5: Tower Height
The obtained height of the parabola in the data path profiling is insufficient because the graph shows that LOS would not be possible, the proponents decided to increase the obtained parabola height to 71 meters.
Tower Height = parabola height + ½ antenna diameter
Tower Height = 41.915 + (0.5) (3) Tower Height = 43.415 meters
Tower Height for each site:
Site A: 44m Site B: 44 m o The suitable tower height to be used is 44 m.
Item 6: Tower Type Site A: Three – self-supporting structures (RS75) 70
Site B: Three – self-supporting structures (RS75)
Item 7: Azimuth
The azimuth of a point is measured by the arc of the horizon beginning at the north, extending eastward and terminating at the vertical circle of the body.
Site A: 118° N Site B: 118° N
Item 8: Path Length
Path length is the distance from one site to another in a straight line D = 38.46332 km
Item 9: Path Attenuation
Path attenuation or free space loss is defined as the loss that would be obtained between two isotropic antennas in free space, where there are no ground influences of obstructions. That is, where blocking, refraction, diffraction and absorption do not exist. It is given by formula:
FSL = 92.4 + 20 log fGHz + 20 log dkm Where in:
FSL = free space Loss F = frequency used in GHz D = distance between two stations in Km
The frequency can be obtained as follows:
fo = center frequency of the band of frequencies occupied Fn = center frequency of one radio frequency channel in the upper half of the band in GHz F„n = center frequency of one radio frequency channel in the lower half of the band in GHz
The frequencies of the individual channel are expressed by relationship: Upper half of the band: fn = fo – 10 + 40(n) Lower half of the band: fn = fo – 10 + 40(n)
The preferred center frequency is 6770 MHz as specified in
Recommendations 384-4. The chosen is equal to channel 8 and using the upper half of the band: Fn = 6770 – 10 +40(8) Fn = 7.08GHz
Now, FSL = 92.4 + 20 log 7.08 + 20 log 38.46332 FSL = 141.1016 dB Item 10: Length of Rigid Waveguide
Rigid waveguide Length = Tower height + Assumed Allowance (eq. 4.19)
Rigid waveguide Length = 44 m + 6 m
72 Site A: 50 m Site B: 50m
Item 11: Length of Flexible Waveguide
The approximate length of a flexible waveguide is 10ft or 3.048m.
Site A: 3.048 m Site B: 3.048 m
Item 12: Waveguide Loss
Rigid Waveguide Loss = Waveguide Length x Attenuation
for site A:
Rigid Waveguide Loss = 50 m x 5.8 dB/100m RWGloss = 2.9 dB
for site B:
Rigid Waveguide Loss = 50 m x 5.8 dB/100m RWGloss = 2.9 dB
Flexible Waveguide Loss = Waveguide Length x Attenuation
for site A: Flexible Waveguide Loss = 3.048 m x 0.3 dB/m FWLloss = 0.9144 dB for site B: Flexible Waveguide Loss = 3.048 m x 0.3 dB/m FWLloss = 0.9144dB Waveguide Loss = Rigid Waveguide loss + Flexible Waveguide loss
For site A: WGloss = 2.9 + 0.9144 WGloss = 3.8144 dB For site B: WGloss = 2.9 + 0.9144 73
WGloss = 3.8144 dB Item 13: Connector Loss
Connector is accumulated item for small losses associated with pressure windows, bends and flanges. The value of 0.5dB per station is typical and safe for most waveguide runs. (Assumed value)
Site A: 0.5 dB Site B: 0.5 dB
Item 14: Circular or Hybrid Loss
There is no circulator or hybrid used externally to the equipment, so circulator loss equal to 0 dB. (Assumed Value)
Item 15: Radome Loss
Radome is a plastic protective enclosure for the antenna. Radome loss is specified at 0.5dB for each parabolic antenna. Unheated type is used considering the atmospheric conditions on both sites. (Assumed Value)
Site A: 0.5dB Site B: 0.5dB
Item 16: Total Fixed Loss
Fixed loss = Waveguide loss + Connector Loss + Radome Loss + Hybrid Loss (eq. 4.20)
For site A: 3.8144 dB+0.5 dB+ 0.5 dB
=4.8144 dB For site B: 3.8144 dB+0.5 dB+ 0.5 dB = 4.8144 dB
Total Fixed Loss = 2(4.8114) = 9.6228dB
Item 17: Total Loss
Total Loss = Free Space Loss + Total Fixed Loss = 141.1016 dB+ 9.6228 Total Loss = 150.7244 dB
Item 18: Parabolic Height
Site A: 41.915 m Site B: 41.915 m
Item 19: Parabola Diameter
The obtained diameter is 3.64 m but since the next available height is 3.7 m, the latter was used in the course of the design.
Item 20: Antenna System Gain
G = 17.8dB + 20 log d + 20 log fGHz
G = antenna gain F = frequency in GHz D = diameter in m 75
The antenna system gain provides the gain of each antenna to be used for the two sites
G = 17.8 dB + 20 log3 + 20 log 7.08 G = 44.343 dB
The gain of the antenna used (3 m antenna diameter) is 44.343 dB.
Item 21: Total Gain
The total gain of the antenna system using the actual diameter of the parabola is equal to the sum of antenna gain in each site.
Total Gain = GA + GB = (44.343+ 44.343) dB Total Gain = 88.686dB
Item 22: Net Path Loss
Net path loss = Total Loss – total Gain = (150.7244 –88.686) dB Net Path Loss = 64.0384 dB
Item 23: Transmitter Power Output
From the transmitter-receiver specification of the NEC Corporation Transmitter Power Output = 30 dBm
Item 24: Medium Received Power Medium Received Power = Transmitter Power Output – Net Path Loss (eq. 4.22) 76
= 30 dBm – 64. 0384dB Medium Received Power = -34.0384dBm
Item 25: Practical Threshold
From the specification of the NEC Corporation Practical Threshold = -78 dBm
Item 26: Fade Margin
Fade Margin = Medium Received Power + Practical Threshold (eq. 4.23) = -34.0384- (-78dBm) Fade Margin = 43.9616 dB Item 27: Reliability = (1 – Undp) x 100% ( )
Undp = non-diversity annual outage probability for a given path a = 0.25; for an average terrain, with some roughness b = 0.25; for normal interior temperate area f = frequency in GHz = 7.08 D = total path length in km = 43.9616 FM = fade margin in dB = 34.0104 dB
Reliability = (1 – Reliability = 99.999%
E. Microwave Path Data Calculation Sheet
Table 4.2 Microwave Path Data Calculation Sheet
1 2 3 4 5 6 7 8 9 10 11 12
Site Latitude Longitude Elevation Tower Height Tower Type Azimuth Path length Path Attenuation Length of Rigid Wave Length of Flexible Wave Waveguide Loss A. Rigid Waveguide Loss B. Flexible Waveguide Loss Connector Loss Circular Loss Radome Loss Total Fixed Loss Total Loss Parabolic Height Parabola Diameter Antenna System Gain Total Gain Net Path Loss Transmitter Power
Output Medium Received Practical Threshold Fade Margin Reliability
Panabo, Unit Davao del Norte Degree 7°26’38.02‖ N Degree 125°46’35.84″E Meter 13.1064 Meter 49.375 3ST-RS75 Degree Km 38.46332 dB 141.1016 Meter 55.475 Meter 3.048 dB dB dB dB dB dB dB dB Meter Meter dB dB dB dbm dBm dBm dB % 4.0424 3.218 0.9144 0.5 0 0.5 10.0848 151.1894 48.475 3.7 46.1647 92.3294 58.857 30 -28.857 -78 49.143 99.99920173
Kapalong, Davao del Norte 7°37’46.81‖ N 125°43’03.52”E 19.2024 49.375 3ST-RS75 38.46332 141.1016 55.475 3.048 4.0424 3.218 0.9144 0.5 0 0.5 10.0848 151.1894 48.475 3.7 46.1647 92.3294 58.857 30 -28.857 -78 49.143 99.99920173 78
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
CHAPTER V Summary, Conclusions and Recommendations
Many factors are need to be considered in choosing the province where to establish a point-to-point microwave system, and after considering those factors, the researchers chose Panabo , Davao del Norte as their Site A and Kapalong, Davao del Norte as their Site B. Some of important factors on communication system design were also considered and it is based on the CCIR Recommendation. Used microwave equipment was based on the specifications from Andrew Company where some of the significant parameters and values are being taken.
Microwave Engineering antenna and necessary parameters were deeply analyzed and determined based on the principal theories and principles about microwave propagation. Many formulas from microwave communication system principles are used to obtain all the significant parameters to be considered for the design. These parameters include the path parameters such as operating frequency, free space loss, system fixed loss, fade margin and system reliability; design parameters such as height of communication tower, Fresnel clearance, height clearance due to earth’s curvature and antenna gain. These are the factors considered for determining the proper equipment to be used and ensure a line-of-sight propagation between the two selected sites.
The reliability of the communication system is also determined by the proponents to obtain the desired signal propagation and aim to compute actual reliability of 99.9999% for it is needed for other parameter computations. The factors to be considered for establishing the design are the site selection, obstruction calculations, path parameters, tower parameters and cost of the 79
design. The obstruction calculation will greatly affect the LOS transmission, that it can completely block the signal from the tower to another tower, to avoid this, the proponents considered the highest obstruction present between the two sites and choose better elevation for the site towers to perfectly establish LOS propagation.
The highest obstruction must be carefully examined with the addition of tree clearance, Fresnel zone clearance and height due to Earth’s curvature that considered as the total elevation of obstruction (TEO). Also the calculation of transmission losses and gains considering the net path loss from the beginning until the signal reached the other site is necessary. Losses to be determined are the transmitter line loss of the waveguide, free space loss, waveguide loss in the receiver side, and fade margin. The proponents are able to complete the research with the computations and data path profile and met necessary requirements for the site selection and tower construction.
The proponents conclude that:
1. The location of the site is very important for the design before the parameters, the values and parameters depends on the data of the sites. In choosing a site location, many factors are to be considered such as the operating frequency, free space loss, system fixed loss, fade margin, system reliability, height of communication tower, antenna gain, waveguide losses and total height of obstruction (TEO) due to highest obstruction, Fresnel clearance, earth curvature and additional clearance antenna gain. These factors are considered in choosing the proper equipment to be used and constructing the appropriate towers and parabolic antennas.
2. It is hard to locate or determine the highest obstruction present between the two sites without their specific location. Using the internet for the data path profile instead of the topographical map may also decrease the accuracy of the measured distance. Considering the criteria regarding the selection of the sites, the proponents arrived at Panabo, Davao del Norte as their Site A linking to Kapalong, Davao del Norte as their Site B.
3. For presenting the path calculations that needs to be considered for the design, the researchers set the standards which they had saw on references such as the CCIR Recommendation 384-4 and the theories and principles regarding microwave propagation and became the basis of this study. Considerations such as obstructions and the types of terrains that will be encountered by the signal, which have to be avoided, the availability of power in the sites, the elevation, meteorological conditions, and the required signal level to be received, existing phenomenon like the Fresnel phenomenon, clearances provided due to the curvature of the Earth and vegetation, etc. should not be violated for the design process or else the design may come up to unreliable signal transmission and expensive cost of design.
4. After obtaining the necessary parameters, the equipment such as waveguide, transceivers, tower specification, and diameter of parabola will then be easy to identify. The chosen model should satisfy some parameters especially regarding with the dimensions.
5. Base on the standards from the specifications given by CCIR Recommendation 384-4, it is possible to attain a percent reliability greater than 99.9999% as to the operation of the microwave system designed by the proponents. The losses have been minimized; the components have been carefully chosen to be 99.9999% reliable.
After the success of the design, the proponents recommends to other researchers especially for those engineering students to research more about microwave engineering to enhance their knowledge about line-of-sight propagation. For those who will be given the same project, always take note that every parameter should be considered and calculated with reliable and accurate data to avoid design failure.
The university instructors should pursue the microwave engineering for the engineering students especially for electronics engineering to practice the students in the field before they work in reality after graduating.
To book authors, they should write more about microwave engineering using the modern technology coming out in the industry. This would greatly help the students and designers in the design process to enhance their skills and knowledge for establishing a microwave antenna system.
Manufacturing companies producing microwave towers, parabolic antennas and waveguides should continue their production of equipment and components for there are many possible design\s to be considered and maybe in the future be approved for construction. Established engineering companies also might be a great help in testing the educational methods, they have the most advanced technology that will help to determine the effectiveness of design.