Introduction
Microwaves are generally describes as electromagnetic waves with frequencies that range from approximately 500 MHz to 300 GHz or more. Therefore, microwaves signals, signals, because because of their inherently inherently high frequencies, frequencies, have relatively relatively short wavelengths wavelengths,, hence the name” micro” waves. For example, a 100 GHz microwave signal has a wavelength wavelength of 0.3 cm, whereas whereas a 100 MHz commercial commercial broadcast-band broadcast-band FM signal has a wavelength of 3 m. the wavelengths for microwave frequencies fall between 1 cm and 60 cm, slight slightly ly longer longer than than infrar infrared ed energy. energy. For full full duplex duplex (two-w (two-way) ay) operation operation as is general generally ly requir required ed of microw microwave ave commun communica icatio tions ns syste systems, ms, each freque frequency ncy band is divided in half with the lower half identified as the low band and the upper half as the high band. At any given radio station, transmitters are normally operating on either the low or the high band, while receivers are operating on the other hand. There are many different types of microwaves systems operating over distances that vary from 15 miles to 4000 miles in length. Intrastate or feeder service microwave systems are general generally ly catego categoriz rized ed as short short haul because because they they are used used to carry carry inform informati ation on for relati relativel vely y short short distan distances ces,, such such as betwee between n cities cities within within the same same state. state. Long Long haul microwaves systems are those used to carry information for relatively long distances, such as interstate interstate and backbone route applications. applications. Microwave Microwave radio systems systems capacities capacities range from less than 12 voice-band channels to more than 22 000 channels. Early microwaves systems carried frequency-division-multiplexed voice-band circuits and used conventional, no coherent frequency modulation techniques. More recently developed microwave microwave systems systems carry pulse-code-m pulse-code-modulat odulated ed time-divis time-division-m ion-multi ultiplexed plexed voice-band voice-band
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circuits and used more modern digital modulation techniques, such as Phase Shift Keying (PSK) or Quadrature Amplitude Modulation (QAM).
Capabilities of Microwave
Micr Microw owav avee
trans ransm missi ission on
is
gene generrally ally
def defined ined
as
the
trans ansmiss missiion
of
electromagnetic waves whose frequency falls approximately in the range between 1 Gigahertz and 50 Gigahertz (wavelengths of 30 cm to 6 mm). The propagation through the atmosphere of signals in this frequency range exhibits many of the properties of light, such as line-of-si line-of-sight ght transmiss transmission, ion, reflectio reflection n from smooth surfaces, surfaces, etc. Microwave Microwave systems have many applications in the telephone industry because high quality circuits can be derived for intertoll trunks, toll connecting trunks, extended area service trunks, subscriber service and special services. Microwave is also suitable for transmission of blac black k and and white white or colo colorr tele televi visi sion, on, data data,, and and data data under under voice voice,, with with negl neglig igib ible le impairment from impulse noise, delay distortion, frequency error, frequency response, or steady state noise. Another attractive aspect of microwave is the ease with which channels can be added or removed after the basic radio frequency (RF) and carrier multiplex equipment is installed. Certain types of RF equipment will carry up to 2000 or more voice channels without any change in the basic RF equipment. The problems associated with cable facili faciliti ties es such such as physic physical al damage, damage, induct induction ion noise, noise, rightright-of of way proble problems, ms, circui circuitt expansion limitations and similar problems are reduced with the use of microwave. The initial cost of a microwave system depends on the type of radio frequency and multiplex equipment used the number of channels, the number of hops in a system,
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the terrain, the type of antennas, the cost of the necessary towers and other factors. In some cases microwave will require a lower initial investment, provide greater reliability, and have lower operating costs and maintenance than cable facilities. It is highly desirable to use digital microwave equipment for all new installations in order to eventually achieve a complete integrated digital network. The only exception to this would be in the event that a borrower wants to use the microwave equipment to carry television signals. Analog equipment is the best choice for the current standard television channel. The input and output baseband signal for a digital microwave radio is a single bit stream. This may range from approximately 1.544 Mb/s to approximately 144 Mb/s. The baseband signal is used to modulate a radio frequency carrier. The RF carriers used range from 2 GHz to 24 GHz.
COMPONENTS OF A MICROWAVE SYSTEM Transmitters and Receivers . The basic building blocks of a microwave system
are the radio frequency frequency (RF) transmitter transmitterss and receivers. receivers. These units make it possible to send and receive information at microwave frequencies. Most microwave transmitters are capable of an output power of one watt or more. A transmitter used in a terminal location has provisions for modulating the RF carrier with baseband signals from the carrier multiplex equipment. Receivers are capable of providing a useable baseband output with received microwave signal levels as low as -80 dBm. A terminal receiver includes a demodulator to provide the baseband output to the carrier multiplex.
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Carrier Multiplex. The microwave RF equipment has a wide bandwidth which is
capable of carrying many channels of information. These channels are derived using multiplex equipment which can combine several hundred channels for transmission over one RF channel in a single bit stream. Antennas. A parab parabol olic ic or a horn horn ante antenn nnaa is used used in micr microwa owave ve syst system emss to
concentrate radiated energy into a narrow beam for transmission through the air. This resu result ltss in the the most most effi effici cien entt tran transm smis issi sion on of radi radiat ated ed powe powerr with with a mini minimu mum m of interference. An effective gain of 25 to 48 dB over an ommi-directional antenna is possible depending upon the size of the antenna and the microwave frequency used. Radomes. A radome is a protective covering used to prevent snow, ice, water, or
debris from accumulating on a microwave antenna. Heated radomes are available for use in areas where severe ice and snow conditions exist. The use of a radome results in lower antenna gain. Transmiss ission ion lines lines provid providee the means means of couplin coupling g the Transmission Transmission Lines. Transm trans transmi mitt tter er and and rece receiv iver er to the the ante antenna nna.. Ther Theree are are two two type typess curr curren entl tly y avai availa labl ble: e: wavegui waveguide de and coaxial coaxial cable. cable. The radiat radiated ed output output power power of the transm transmit itter ter will will be substantially reduced if the transmission line is incorrectly used or if its length is too long long,, so prec precaut autio ions ns shou should ld be take taken n to use use the the corr correc ectt type type of line line for for the the radi radio o equipment used, and to keep all transmission line lengths short. Waveguide. A waveguide is a hollow metal duct which conducts electromagnetic
energy. This type of transmission line can be u sed for distances of a few feet up to several hundred feet. A typical type of waveguide has a loss from about 1.7 dB per hundred feet at 6 Gigahertz (GHz) to about 3.0 dB per hundred feet at 11 GHz. It is used at microwave
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frequencies above 2 GHz and can have either a rectangular, elliptical, or circular crosssection, depending upon the system operation requirements. The length of a waveguide run is more critical at higher frequencies since attenuation increases with frequency. All waveguide runs are pressurized. Coaxial Cable. At low microwave frequencies, 2 Ghz or less, coaxial cable can
be used as the connecting facility between the transmitter, receiver and antenna instead of wavegui waveguide. de. The loss loss of coaxia coaxiall cable cable depends depends on the type of conduct conductor, or, the cable cable diamet diameter, er, the type type of dielec dielectri tric, c, and the operat operating ing freque frequency ncy.. Coaxial Coaxial cable with with a diameter of one inch or more should be used for long cable runs; 7/8" diameter coax can be used satisfactorily for short runs. The coaxial cable can have either a pressurized air or expanded polyethelyne (foam) dielectric between conductors, however, the air dielectric coaxial coaxial cable cable has less less attenu attenuati ation on for a given given diamet diameter. er. In genera general, l, pressu pressuriz rized ed air dielectric coaxial cable is used with higher capacity systems because the return loss characteristics of foam dielectric lines may be a significant distortion contributor in such systems. This is not usually a consideration in systems of low channel capacity. The cost of coaxial cable is less than waveguide and should be used when possible. Extreme attenuation of radio signals above 2 GHz in the coaxial cable generally prohibits its use at the higher microwave frequency bands. Reflectors. A passive reflector can sometimes be used in systems operating near a
power substation to avoid the electromagnetic interference (EMI) potential in place of using long runs of waveguide connected to a parabolic antenna at the top of the tower. A reflector reflector may be mounted at a 45 degree angle at the top of the tower, while the antenna is mounted horizontally at the base of the tower, aimed at the reflector. The microwave
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signal is radiated from the antenna, reflected off the reflector, and sent in a direction of propagation to the other end of the radio path, just as though the antenna was radiating direct directly ly from from the top of the tower. tower. However, However, this this type type "peris "periscope cope"" or "fly "fly swatte swatter" r" antenna system will not be authorized by the FCC under ordinary circumstances because of its interference potential with communications satellites. A waiver from the FCC is required. Towers. The towers used in microwave systems must be rigid to prevent antenna
deflection during wind or ice loading conditions. Guyed or self-supporting towers are available for use on microwave systems. A guyed tower is about one-third the cost (per foot, installed) of a self-supporting tower, but in some cases the difficulty of acquiring enough land for guying prohibits the use of guyed towers. The height of the tower is determined by the terrain, the microwave frequency band used, the propagation characteristics, the distance between the transmitting and receiving ends of a path, and the required reliability. The tower must be high enough to provide a lineof-sight path above any obstructions. If reflection interference is a problem, the antenna mounting heights are critical and the optimum height may be less than the maximum height available on the tower. Buildings. Micr Microw owave ave equip equipme ment nt shou should ld be loca locate ted d in the the cent centra rall offi office ce
equipme equipment nt buildi building ng when when possib possible. le. There There are some some situat situation ions, s, however however,, when when RF equipment must be located remotely from a central office building, as in the case of an active RF repeater. In these situations some type of building must usually be provided for equipme equipment nt protec protectio tion. n. Usuall Usually y a simple simple prefab prefabric ricate ated d buildi building ng is suffic sufficien ient. t. Where Where temper temperatu ature re and humidi humidity ty variat variation ionss exceed exceed the operati operating ng limits limits of the microw microwave ave
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equipme equipment, nt, a heater heater or air condition conditioner er is requir required ed to keep keep the equipme equipment nt within within its operating temperature range. Primar Primary y and Standby Standby Power Power Equipme Equipment nt . Prim Primar ary y power power sour source cess for for RF
equipment may be DC or AC as specified by the purchaser. Central office batteries or 117 volts AC commercial power may be used. In some cases, thermoelectric generators or fuel cells can be used when the power requirements of the microwave equipment are low. Standby power equipment should be provided at microwave terminals or active repeater locations to maintain system operation in the event of a commercial power failure. Communication circuits are very important during times of emergency such as stor storms ms,, floo floods ds and and othe otherr disa disast ster erss whic which h may may caus causee comm commer erci cial al powe powerr outage outages. s. Therefore, it is imperative that some type of standby power source be available for circuits derived by microwave. When microwave equipment is located in a central office building, building, stand-by power is usually available from central central office office equipment equipment batteries or an engin engine-g e-gen ener erat ator or.. Howev However er,, at remo remote te site sitess stan standb dby y power power must must be prov provid ided ed specifically for the microwave equipment. The stand-by power source may be batteries, an engine-generator or in some cases a thermoelectric generator, fuel cell or solar energy.
Alarm Systems. Systems. When a microwave microwave system has remote remote unattended unattended stations, itis
desirable to have an alarm system system which will report faults faults from the remote remote location to an attended office via the microwave signal. These alarms will expedite the maintenance of microw microwave ave system systemss and reduce reduce the circui circuitt outage outage time. time. Where Where alarms alarms from from a large large number number of unatten unattended ded statio stations ns are report reported ed to a centra centrall mainte maintenanc nancee contro controll center center,,
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consideration is often given to a computer-based alarm reporting system which prints out all changes in status at each station with time and date information.
Definition of Terms Absorption - the reduction in power density due to non-free space propagation. Antenna - a metallic conductor system capable of radiating and capturing
electromagnetic energy. Attenuation - the reciprocal of gain .The ratio of the input quantity to the output ou tput
quantity. Azimuth - is the horizontal angular distance from a reference direction, either the
southern or northern most point of the horizontal. Azimuth angle - the horizontal pointing pointing angle of an earth station antenna. Bandwidth - the maximum range of frequency, including guard bands, assigned to a
channel Baseband - describes the modulating signal (intelligence) in a communication system. A
single message channel is baseband. Characteristic Impedance of Free Space - is equal to the square root of the ratio of its
magnetic permeability to its electric permittivity. Clutter Loss - attenuation due to trees and buildings in the front of the antenna be
propagated and back by the ionosphere. Critical Angle- a maximum vertical angle of frequency at which it can be propagated
and still be refracted back by b y the ionosphere.
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Critical Frequency - the highest frequency that can be propagated directly upward and
still be returned earth by the ionosphere. dBm- used to reference the power po wer level at a given point to one milliwatt. Decibel (dB) - the basic yardstick used for making power measurements in
communications. Diffraction - the modulation or redistribution of energy within a wave front when it
passes near the edge of an opaque object. It is the phenomenon that allows light or radio waves to propagate (peek) around corners. Digital Modulation - is the transmitted of digitally modulated analog signals (carriers)
between two or points in a communications system. Direct waves- (see free space path) Dispersive Fade Margin - gains in the equipment which are factored in because of
technical improvements on the system and how h ow they improved the information signal itself. E- lines – European digital carrier system. Fading - variations in the field strength of radio signal, usually gradual, that are caused by
changes in the transmission medium. Field intensity - the intensity of the the electric and magnetic fields of an electromagnetic
wave propagating in free space. Flanges - interconnect parts of a microwave antenna system together. Free Space Path - is the line of signal (LOS) path directly between transmit and receive
antennas (this is also called the direct waves).
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Free Space Path Loss - the loss incurred by an electromagnetic wave as it propagates in a
straight line through vacuum with no absorption or reflection of energy by nearby objects. quan tity, the Frequency - the number of cycle computed per second by an alternating quantity, term usually used in describing frequency is cycle per seco nd, on hertz. Fresnel zones - described the amount of the front lobe power to the back lobe power of an
antenna. Full Duplex (FDX) - (see duplexing). Great Circle Distance - it is the shortest distance between any two p oints on a sphere. Ground Wave - an electromagnetic wave that travels along the surface of earth.
Sometimes called “surface waves”. Guard Band- a narrow frequency band provided between adjacent channels in certain
portions of the radio spectrum to prevent interference between stations. Half Duplex - data transmission is possible in both directions but not at the same time. K- Factor- the ratio of a hypothetical effective earth radius over 6370 km, which is the
true mean earth radius. Maximum Usable Frequency (MUF) - the highest frequency that can be used for sky-
wave propagation between two specific points on earth’s surface. Microwave communication - a high radio frequency link specifically designed to
provide signal connection between two specific points.
Polarization - orientation of the electric field vector in respect to the surface of the earth. Power Density- the rate at which energy passes p asses through a given surface area.
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Radio Frequency (RF) Propagation - free-space propagation of electromagnetic waves. Radio Horizon - the curvature of earth presents a horizon to space-wave propagation. Receiver threshold - the minimum wide band carrier power (Cmin ) at the input to a
receiver that will provide a usable baseband output. Reflection - the ability of electromagnetic transmission to bounce off a relatively smooth
surface. Refraction - the in direction of a ray as it passes obliquely from one medium to another
with different velocities of propagation. Skip distance (d s) – the minimum distance from a transmit antenna that a sky wave of
given frequency (which must be less than the Maximum Usable Frequency (MUF)) will be returned to earth. Surface wave - (see ground wave). Waveguide - a special type of transmission line that consist of a conducting metallic tube
through which high frequency electromagnetic energy is propagated.
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Description of the link
This long, over water link supports the wireless communication between Sagnay, Camari Camarines nes Sur and San Andres, Andres, Catandu Catanduane anes. s. The connect connectivi ivity ty requir requires es 10 voice voice channels, 10 video channels, 10 data channels and 10 spare channels which would be required for future expansions. This microwave radio link has a line type of 1xE3 with a rate of 34.368 Mbps and a capacity of 480 channels. It operates in the 7.89 GHz to 8.20 GHz common carrier band allocated to fixed point-to-point service. This frequency band was chosen since the rain attenua attenuati tion on at these these freque frequenci ncies es will will not be a limiti limiting ng factor factor in the link link reliab reliabili ility ty.. Although the link is only 59 km long, the height restriction on the tower antenna required 100m at both site to provide adequate path clearance, and to avoid diffraction loss and clutter loss. Using QPSK modulation the radio unit has an enough transmit power at both site and have a much lower receive threshold. Since the elevation of the site A and site B are different, we compute for the vertical inclination of the antenna. For the difference in height of 286m, by using trigonometry we found that the vertical inclination of the antenna is 0 16’ 39.85”.
̊
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MICROWAVE PLANNING
Condition:
Path length: 59 km Reliability requirement: 99.9999% Configuration: Non-protected (1 + 0) Traffic capacity: 1 x E3 with a rate rate of 34.368 Mbps and a capacity of 480 channel. Site A: Latitude:
13o 34’ 3”
Longitude: 123 o 31’ 22.5” Site B: Latitude:
13o 38’ 15”
Longitude: 124 o 31’ 52.5”
LOCATION
LONGITUDE
LATITUDE
SITE A: Sagñay, Camarines Sur
1230 31’ 22.5”
130 34’ 3”
SITE B: San Andres, Catanduanes
1240 3’ 52.5 “
130 38’ 15”
Computation for azimuth angle
C= Longitude B – Longitude A = LOB – LOA = 124˚ 3’ 52.5” - 123˚ 31’ 22.5” = 0˚ 32’ 30” ½C = 0˚ 16’ 15” (LB + LA) = 13˚ 38’ 15” + 13˚ 34’ 3” = 27˚ 12’ 18” ½(LB + LA = 13˚ 36’ 9” (LB - LA) = 13˚ 38’ 15” - 13˚ 34’ 3” = 0˚ 4’ 12”
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½(LB – LA) = 0˚ 2’ 6” Log tan ½ (Y+X) = log cot ½ C + log cos ½ (L B – LA) – log sin ½ (L B + LA) tan½ (Y+X) = log -1 [log cot ½ C + log cos ½ (L B – LA) – log sin ½ (L B + LA)] ½ (Y+X) = tan -1 {log -1[log cot ½ C + log cos ½ (LB – LA) – log sin ½ (L B + LA)]} ½ (Y+X) = tan -1 {log -1 [log cot 0˚ 16’ 15” + log cos 0˚ 2’ 6” – log sin 13˚ 36’ 9”]} ½ (Y+X) = 89˚ 56’ 10.69”
Log tan ½ (Y-X) = log cot co t ½ C + log sin ½ (LB – LA) – log cos ½ (LB + LA) tan ½ (Y-X) = log -1[log cot ½ C + log sin ½ (LB – LA) – log cos ½ (LB + LA)] ½ (Y-X) = tan -1{log -1 [log cot ½ C + log sin ½ (L B – LA) – log cos ½ (L B + LA)]} ½ (Y-X) = tan -1{log -1 [log cot 0˚ 16’ 15”+ log sin 0˚ 2’ 6”- log cos 13˚ 34’ 3”]} ½ (Y-X) = 7˚ 34’ 20.91”
Log tan ½ (Z) = log tan ½ (L B – LA) + (Y+X) – log sin ½ (Y-X) tan½ (Z) = log -1[log tan ½ (LB – LA) + (Y+X) – log sin ½ (Y-X)] ½ (Z) = 2 {tan -1[log tan 0˚ 2’ 6” + log sin 89˚ 56’ 10.69” - log sin 7˚ 34’ 20.9”]} ½ (Z) = 0˚ 31’ 52.26” + 7˚ 34’ 20.91”
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D = Z *111.12 Where: D = distance in km.
D = 0˚ 31’ 52.26” *111.12 D = 59.02 km
Azimuth Angle
Y = ½ (Y+X) + ½ (Y-X) Y = 89˚ 56’ 10.69” + 7˚ 34’ 20.91” Y = 97˚ 31’ 31.6” X = ½ (Y+X) – ½ (Y-X) X = 89˚ 56’ 10.69”- 7˚ 34’ 20.91” X = 82˚ 21’ 49.78”
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Site A: Sagñay, Camarines sur
Population - 29 082 (2007) Land Area - 108.19 km2 (41.8 sq mi) Barangays – 19 Barangays Mean temperature- 28.76 degrees Celsius Maximum temperature- 31.92 degrees Celsius Mean humidity- 82.94 % Precipitation amount- 99.72 mm Mean wind speed- 9 km/h Maximum wind speed-225 km/h Indicator for occurrence of: rain or drizzle- 3.6 Indicator for occurrence of: thunder- 1.6
Site B: San Andres, Cantanduanes
Population - 33,781 (2007) Land area – 252.40 square kilometer Barangays – 27 Barangays Mean temperature- 25.94 degrees Celsius Maximum temperature- 27.7 degrees Celsius Mean humidity- 89.01 % Precipitation amount- 430.46 mm Mean wind speed- 19.1 km/h Maximum wind speed-240 km/h Indicator for occurrence of: rain or drizzle- 8.9 Indicator for occurrence of: thunder- 1.9
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Transmitter and receiver equipment specifications
CFQ series 8 GHz digital microwave radio unit Frequency range: 7.7 GHz – 8.3 GHz Waveguide: WR112 Frequency = 7.05-10.00 GHz Internal dimension = 1.122 x 0.497 in. Connector: BNC F/F NI/SI UG-914/U 8 GHZ VSWR 1.25 ROHS Flange: Antenna:
UBR 84 VP4-71W Where: VP = unshielded, single polarized 4 = 4 ft., 1.2 m in diameter 71W = 7.125 GHz – 8.5 GHz
Type of map
Topographical Map Scale = 1:250,000
Frequency band required.
8 GHz for 60 km
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Channel plans available.
Frequency band: 8 GHz Frequency range: 7.7 GHz to 8.3 GHz Low band range: 7747.70 MHz to 7955.25 MHz High band range: 8059.02 MHz to 8266.57 MHz Duplex spacing: 311.32 MHz Channel bandwidth for 1x E3: 28 MHz
No. of duplex channels = 7955.25 MHz - 7747.70 MHz 28 MHz = 7.41 (7 channels)
Selecting 5 channel spacing above the high band and low band edge:
28 MHz * 5 = 140 MHz Low Band Frequency 7747.70 MHz + 140 MHz = 7887.70 MHz High Band Frequency 8059 MHz + 140 MHz = 8199.02 MHz
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Minimum elevation of site A and site B.
h = d2/(12.75* k)
Where: d = (path length in km)/2 h = minimum site elevation in m. k = 4/3
h = 29.52/ [12.75* (4/3)]
h = 51.19 m
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Table plotting points along the path.
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2
2
2
Determining minimum reliable tower height
Lk =
d1d2/ 12.75* k
Lf = 17.3 * F % *
L = Lk + LF + LHF
Lk =
29 *30 12.75 *(4/3)
Lk = 51.18 m
LF = 17.3 * 0.60 * LF = 14.18 m L = Lk + LF + LFH = 51.18 m + 14.18 m + 386 m L = 451.36 m Where: L = clearance criteria in meters Lk = curvature factor in meters Lf = fresnel factor in meters LFH = arbitrary fixed height in meters d1 = distance from site A to point, in kilometer k ilometer d2= distance from site B to point, in kilometer D = path distance in kilometer F% = fresnel zone percentage factor f lower = low band transmit frequency in GHz Clearance Criteria
At Fixed Height of 386 Meters
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Reflection Point looking from Site A (Transmitter at 100 m above MSL)
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Fade Margins
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Radio Configuration = Outdoor Mounted RF Module (ODU) Transmit Power = 32 dBm Receiver Threshold (1 x E3 at 8 GHz) = -86 dBm Flexible Waveguide loss:
Low band frequency = (0.2624 dB/m) (0.6) = 0.1574 dB High band frequency = (0.2624 dB/m) (0.6) = 0.1574 dB
Antenna used = 1.2 m in diameter (8 GHz) with Mid Band Gain of 37.5 dB Waveguide used = WR112 (0.6 m flexible waveguide in site A and site B) Connector Loss = 0.5 dB Free Space Loss (FSL):
For Low Band: FSL = 92.45 + 20 log10 (f * d) FSL = 92.45 + 20 log10 (7.89 * 59) FSL = 145.81 dB
For High Band:
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FSL = 92.45 + 20 log10 (f * d) FSL = 92.45 + 20 log10 (8.20 * 59) FSL = 146.14 dB Where: f = frequency d = path length in Km
Computation for Low Band Frequency (7.89 GHz)
PARAMETERS Microwave Radio Output Power Connector Loss (TX) Flexible Waveguide Loss (TX) Antenna Gain (TX) Free Space Loss (FSL) Antenna Gain (RX) Connector Loss (RX) Flexible Waveguide Loss (RX) Power Input to Receiver (RSL) Minimum Receiver Threshold Thermal Fade Margin
VALUE 32.00 0.50 0.16 37.50 145.81 37.50 0.50 0.16 -39.13 -86.00 42.87
UNITS dB m dB dB dB dB dB dB dB dB dB m dB
Computation for High Band Frequency (8.20 GHz)
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PARAMETERS Microwave Radio Output Power Connector Loss (TX) Flexible Waveguide Loss (TX) Antenna Gain (TX) Free Space Loss (FSL) Antenna Gain (RX) Connector Loss (RX) Flexible Waveguide Loss (RX) Power Input to Receiver (RSL) Minimum Receiver Threshold Thermal Fade Margin
VALUE 32.00 0.50 0.16 37.50 146.14 37.50 0.50 0.16 -39.46 -86.00 46.54
UNITS dB m dB dB dB dB dB dB dB dB dB m dB
Dispersive Fade Margin
Dispersive Fade Margin at 1 x E3 is 90 dB. Interference Fade Margin
Assume that no interference fade margin is given; therefore it is not included in the computation.
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Frequency in GHz 1
k H
k V
αV
αH
0.0000387
0.0000352
0.1920000
0.880000
2
0.0001540
0.0001380
0.9630000
0.923000
4
0.0006500
0.0005910
1.1210000
1.075000
6
0.0017500
0.0015500
1.3080000
1.265000
7
0.0030100
0.0026500
1.3320000
1.312000
8
0.0045400
0.0039500
1.2760000
1.310000
10
0.0101000
0.0088700
1.2170000
1.264000
12
0.0188000
0.0168000
1.1540000
1.200000
15
0.0367000
0.0335000
1.0990000
1.128000
20
0.0751000
0.0691000
1.0610000
1.065000
25
0.1240000
0.1130000
1.0610000
1.030000
30
0.1870000
0.1670000
1.0210000
1.000000
35
0.2630000
0.2330000
0.9790000
0.963000
40
0.3500000
0.3100000
0.9390000
0.929000
Rain Losses
CCIR/ITU-R Recommendation 530 rain attenuation For Low Band Frequency (7.89 GHz) M = (log10 f 1 – log10 f x)/ (log10 f 1 – log10 f 2)
note: f 1 < f x
M = (log10 7 – log10 7.89)/ (log10 7 – log10 10) M = 0.33
k = k = log10-1 [log10k 1 – M (log10k 1 – log 10k 2)] k = k = log10-1 [log10 0.00887 – 0.33(log10 0.00887 – log10 0.00265)] k = k = 0.00593604 α = α1 – M (α1 – α2) α = 1.276 – 0.33 (1.276 – 1.332) α = 1.29448
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For High Band Frequency (8.20 GHz) M = (log10 f 1 – log10 f x)/ (log10 f 1 – log10 f 2)
note: f 1 < f x
M = (log10 7 – log10 8.20)/ (log10 7 – log10 10) M = 0.44
k = k = log10-1 [log10k 1 – M (log10k 1 – log 10k 2)] k = k = log10-1 [log10 0.0087 – 0.44(log10 0.0087 – log 10 0.00265)] k = k = 0.005212732
α = α1 – M (α1 – α2) α = 1.276 – 0.44(1.276 – 1.332) α = 1.30064
Computation for the effective rain path length
D0 = 35 *ℓ - 0.015* R0.001 D0 = 35* ℓ - 0.015* 180
where: DE = effective rain path length R 0.001 0.001 = rainfall rate at 0.001% outage
D0 = 2.3521 DE = D/1 + (D/D0) DE = 59/1 + (59/2.3521) DE = 2.2619 km
Computation for the unit rain attenuation
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For Low Band Frequency (7.89GHz) k = k = 0.00593604 α = 1.29448
α y = k *(R k *(R 0.001 0.001)
y = 0.00593604 (180) 1.29448 y = 4.9306
For High Band Frequency (8.20 GHz) k = k = 0.005212732 α = 1.30064
α y = k * k * (R 0.001 0.001)
y = 0.005212732 (180) 1.30064 y = 4.4706
Rain Attenuation
For Low Band Frequency (7.89 GHz) A rain = DE * y A rain = (2.2619) (4.4306) A rain = 11.1525 dB
For High Band Frequency (7.89 GHz)
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A rain = DE * y A rain = (2.2619) (4.4706) A rain = 10.1120 dB
Atmospheric Losses
Oxygen absorption loss Computation for absorption loss at a path length of 30 km: A0 = [7.19 * 10-3 + (6.09/f 2 + 0.227) + (4.81/ (f – 57)2 + 1.5)] f 2 * 10-3 dB/km Where: f = frequency in GHz
For Low Band Transmit Frequency (7.89 GHz)
A0 = [7.19 * 10-3 + (6.09/ ((7.89)2 + 0.227) + (4.81/ (7.89 – 57)2 + 1.5)] [(7.89)2 * 10-3 dB/km] A0 = [7.19-3 + 0.0975 + 1.99 * 10-3] [(7.89)2 * 10-3dB/km] A0 = (0.10668) (7.892) (10-3) dB/km A0 = 0.0066 dB/km
Atmospheric Losses for 59 km = (0.0066 dB/km) (59 km) = 0.3894 dB
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For High Band Transmit Frequency (8.20 GHz) A0 = [7.19 *10-3 + (6.09/((8.2 (6.09/((8.20) 0)2 + 0.227) + (4.81/(8.20 – 57)2 + 1.5)][ (8.20)2 * 10-3 dB/km] A0 = [7.19-3 + 0.090266+ 2.02*10-3] [(8.20)2 * 10-3dB/km] A0 = (0.09947) (8.202) (10-3) dB/km A0 = 0.0067 dB/km Atmospheric Losses for 59 km = (0.0067 dB/km) (59 km) = 0.3946 dB
Water Vapor Loss AH2O = [0.067 + (3/f 2 + 7.3) + (9/(f – 1833)2 + 6) + (4.3/(f – 323.8)2 + 10] [f 2 * α *10-4dB/km] Where: f = frequency in GHz α= water vapor density in gm/m3 should be below 12 gm/m3 Computing for water vapor loss at a path length of 59km For Low Band Frequency (7.89 GHz) AH2O = [0.067 + (3/7.892 + 7.3) + (9/ (7.89 – 1833)2 + 6) + (4.3/ (7.89 – 323.8)2 + 10] [7.892 * 10-4dB/km] AH2O = (0.08129) (7.892) (12*10-4) dB/km AH2O = 0.0061dB/km
Water Vapor Loss for 59 km = (0.0061 dB/km) (59km)
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= 0.3583 dB For High Band Frequency (8.20 GHz) AH2O = [0.067 + (3/8.202 + 7.3) + (9/ (8.20 – 1833)2 + 6) + (4.3/(8.20 – 323.8)2 + 10] [8.202* 10-4dB/km] AH2O = 0.0066077 dB/km
Water Vapor Loss for 59 km = (0.0066077 dB/km) = 0.3899 dB
Antenna Misalignment
A 0.5dB overall in the link budget to compensate the misalignment of the antenna during installation.
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2
2
Diffraction loss and clutter loss
Since there is no point along the path comes closer than 150% first Fresnel, there is no need to compute for the diffraction loss and clutter loss.
Table of the given and calculated data
Computation for low band frequency-Tx = 7.89 GHz RSL = transmitter output – (Tx) waveguide loss + (Tx) Antenna gain – FSL + (Rx) Antenna gain – (Rx) Waveguide loss RSL = 32 dBm – 0.16 dB + 37.50 dB – 145.81 dB + 37.50 dB – 0.16 RSL = - 39.13 dB TFM = RSL – Receiver Threshold TFM = -39.13 dB – (- 86 dBm) TFM = 46.87 dB PARAMETERS Microwave Radio Output Power Connector Loss (Tx) Flexible Waveguide Loss (Tx) Antenna gain Free Space Loss (FSL) Atmospheric Losses (Oxygen Absorption) Atmospheric Losses (Water Vapor Loss) Rain Attenuation Antenna misalignment loss Flexible Waveguide Loss (Rx) Antenna gain (Rx) Connector Loss (Rx) Power Input to Receiver (RSL) Minimum Receiver Threshold Thermal Fade Margin (TFM) Dispersive Fade Margin
VALUE
UNITS
32.00 0.50 0.16 37.50 145.81 0.39 0.36 11.15 0.50 0.16 37.50 0.50 -39.13 -86.00 46.87 90.00
dB m dB dB dB dB dB dB dB dB dB dB dB dB dB m dB dB
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Calculation for high band frequency – Tx = 8.20 GHz RSL = Transmitter Output – (Tx) Waveguide loss + (Tx) Antenna Gain – FSL + (Rx) Antenna Gain – (Rx) Waveguide Loss RSL = 32dBm – 0.16dB + 37.50 dB – 146.14 dB + 37.50 dB – 0.16 dB RSL = - 39.46 dB Thermal Fade Margin = RSL – Receiver Rec eiver Threshold TFM = - 39.46 dB – (-86 dBm) TFM = 46.54 dB
PARAMETERS Microwave Radio Output Power Connector Loss (Tx) Flexible Waveguide Loss (Tx) Antenna gain Free Space Loss (FSL) Atmospheric Losses (Oxygen Absorption) Atmospheric Losses (Water Vapor Loss) Rain Attenuation Antenna misalignment loss Flexible Waveguide Loss (Rx) Antenna gain (Rx) Connector Loss (Rx) Power Input to Receiver (RSL) Minimum Receiver Threshold Thermal Fade Margin (TFM) Dispersive Fade Margin
VALUE
UNITS
32.00 0.50 0.16 37.50 146.14 0.39 0.39 10.11 0.50 0.16 37.50 0.50 -39.46 -86.00 46.54 90.00
dB m dB dB dB dB dB dB dB dB dB dB dB dB dB m dB dB
Flat Fade Margin
Calculation for the Flat Fade Margin is given by the formula: FM FLAT = -10 log [10 (-FMthermal/10) + 10 (-FMadj – chan/10) + 10 (-FMint/10) + 10 (-Fmdiff/10)]
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For low band transmit frequency – Tx (7.89 GHz) FMFLAT = -10 log [10 (-46.87/10)] FMFLAT = 46.87 dB For high band transmit frequency – Tx (8.20 GHz) FMFLAT = -10 log [10 (-46.54/10)] FMFLAT = 46.54 dB
Composite Fade Margin
Calculation for the composite or effective fade margin is given by the formula: FM EFF = -10 log [10 (-FMflat/10) + R D *10 (-FMdsp/10)] Where: R D = Fade Occurance Factor For low band transmit frequency – Tx (7.89 GHz) FM EFF = -10 log [10 (-46.87/10) + 7 *10 (-90/10)] FM EFF = 46.8685 dB For high band transmit frequency – Tx (8.20 GHz) FM EFF = -10 log [10 (-46.54/10) + 7 *10 (-90/10)] FM EFF = 46.5386 dB
Reliability Calculation
K – Q Reliability Calculation U = K – Q f b d c * 10 (-FMeff/10) Where: K – Q = Regional K – Q value f = frequency in GHz
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d = Path length in km b,c = Regional Climate Factor FMeff = Effective Fade Margin For low band transmit frequency – Tx (7.89 GHz) ULB = 1 *10 -9* 7.89 1.2 * 59 3.5 * 10 (-46.8685/10) ULB = 3.869 * 10 -7 For high band transmit frequency – Tx (8.20 GHz) UHB = 1 *10 -9* 7.89 1.2 * 59 3.5* 10 (-46.5386/10) UHB = 4.372 * 10 -7 Unfaded Reliability is then computed as 1- unavailability For low band transmit frequency – Tx (7.89 GHz) -7 R LB LB = (1 – 3.869 * 10 ) * 100 %
R LB LB = 99.999961 % For high band transmit frequency – Tx (8.20 GHz) -7 R HB HB = (1 – 4.372 * 10 ) * 100 %
R HB HB = 99.999956%
Using the same value for K – Q of 1*10 -9, b = 1.2 and c = 3.5, the unavailability and reliability for link due to rain can be calculated. Rain Fade Margin = Effective Fade Margin – Rain Attenuation For low band transmit frequency – Tx (7.89 GHz) RFMLB = 46.8685 dB – 11.15 dB RFMLB = 35.7185 dB
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For high band transmit frequency – Tx (8.20 GHz) RFMHB = 46.5386 dB – 10.11 dB RFMHB = 36.4286 dB For low band transmit frequency – Tx (7.89 GHz) ULB = 1 *10 -9 * 7.89 1.2 * 59 3.5 * 10 (-35.7185/10) ULB = 5.042 * 10 -6 For high band transmit frequency – Tx (8.20 GHz) UHB = 1 *10 -9* 8.20 1.2 * 59 3.5 * 10 (-36.4286/10) UHB = 4.484 * 10 -6 Reliability for low band transmit frequency – Tx (7.89 GH z) -6 R LB LB = (1 – 5.042 * 10 )* 100 %
R LB LB = 99.99949 % Reliability for high band transmit frequency – Tx (8.20 GHz) -6 R HB HB = (1 - 4.484 * 10 ) *100 %
R HB HB = 99.99955 %
K – Q Reliability with terrain roughness
Taking the standard deviation of regular increments of the path. M = Average Elevation above MSL
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S = Standard Deviation of the elevations in the path
Where: N = number of path length subdivisions between the two end stations M = Average Elevation within the path S = Standard Deviation of the elevation within the path
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Path elevations do not include site elevations
Sum = Average =
629.00 10.84
188745.00 3254.22
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SD = SD = 56.00 Calculation for the K – Q reliability with terrain roughness is given by the formula: U = (K – Q / S 1.3) * f b *dc * 10(-FMeff /10) Where: K – Q = Regional K – Q value f = frequency in GHz d = Path length in km b and c = Regional Climate Factor FMeff = Effective Fade Margin S = Standard Deviation of the terrain elevation (also called Roughness Factor)
For low band transmit frequency – Tx (7.89 GHz) ULB = (1*10-9 / 56 1.3) * 7.891.2* 593.5 * 10(-46.8685 /10) ULB = 2.065 * 10-9 For high band transmit frequency – Tx (8.20 GHz) UHB = (1*10-9 / 56 1.3) * 7.891.2* 593.5* 10(-46.5386 /10) UHB = 2.334 *10-9
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Unfaded Reliability is then computed as: For low band transmit frequency – Tx (7.89 GHz) -9 R LB LB = (1 -2.065 * 10 ) *100 %
R LB LB = 99.99999979 % For high band transmit frequency – Tx (8.20 GHz) -9 R HB HB = (1 -2.334*10 ) * 100 %
R HB HB = 99.99999977 %
Calculating Rain Fade Margin: RFM = Effective Fade Margin – Rain Attenuation A ttenuation For low band transmit frequency – Tx (7.89 GHz) RFM= 46.8685 dB – 11.15 dB RFM= 35.7185 dB For high band transmit frequency – Tx (8.20 GHz) RFM= 46.5386 dB – 10.11 dB RFM= 36.4286 dB
For low band transmit frequency – Tx (7.89 GHz) ULB = (1 *10 -9/561.3) * 7.89 1.2 * 59 3.5 * 10 (-35.7185/10) ULB = 2.691 * 10 -8 For high band transmit frequency – Tx (8.20 GHz) UHB = (1*10-9 / 56 1.3) * 7.891.2 * 593.5 * 10(-36.4286 /10) UHB = 2.394 * 10-8
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Reliability for low band transmit frequency – Tx (7.89 GH z) -8 R LB LB = (1 – 2.691*10 ) *100 %
R LB LB = 99.9999973 % Reliability for high band transmit frequency – Tx (8.20 GHz) -8 R HB HB = (1 -2.394*10 ) * 100 %
R HB HB = 99.9999976 %
Vigants – Barnette Calculation
The Vigants – Barnette unavailability unav ailability formula is given as: U = 6.0 * 10-7* c * f * d3 * 10(-FMeff /10) Where: c= c factor value which w hich is equal to 4 for the difficult propagation Condition f= frequency in GHz d= path length in km
For low band transmit frequency – Tx (7.89 GHz) ULB = 6.0 * 10-7*4*7.89 * 59 3 * 10 (-46.8685/10) ULB = 7.998 *10 -5 For high band transmit frequency – Tx (8.20 GHz) UHB = 6.0 *10-7 * 4*7.89 * 593 * 10(-46.5386 /10) UHB = 8.969*10-5
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Unfaded Reliability is: For low band transmit frequency – Tx (7.89 GHz) -5 R LB LB = (1 -7.998 * 10 ) *100 %
R LB LB = 99.9920 % For high band transmit frequency – Tx (8.20 GHz) -5 R HB HB = (1 -8.969 * 10 ) * 100 %
R HB HB = 99.10 % Calculation for the unavailability due to rain is done: Rain Fade Margin = Effective Fade Margin – Rain Attenuation For low band transmit frequency – Tx (7.89 GHz) RFM= 46.8685 dB – 11.15 dB RFM= 35.7185 dB For high band transmit frequency – Tx (8.20 GHz) RFM= 46.5386 dB – 10.11 dB RFM= 36.4286 dB
Unavailability during rain: For low band transmit frequency – Tx (7.89 GHz) ULB = 6.0 * 10-7 * 4 * 7.89 * 59 3 * 10 (-35.7185/10) ULB = 1.04 * 10 -3 For high band transmit frequency – Tx (8.20 GHz) UHB = 6.0 * 10-7 * 4 * 7.89 * 593*10(-36.4286 /10) UHB = 9.19858 * 10-4
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The reliability during rain: For low band transmit frequency – Tx (7.89 GHz) -3 R LB LB = (1 -1.04 * 10 ) *100 %
R LB LB = 99.89576963 % For high band transmit frequency – Tx (8.20 GHz) -4 R HB HB = (1 -9.19858 * 10 ) * 100 %
R HB HB = 99.908%
MICROWAVE PATH DATA SHEET Capacity: 1xE3 Low band transmit frequency: 7.89 GHz High band transmit frequency: 8.20 GHz Equipment: CFQ series 8 GHz digital microwave radio unit Site A: Sagñay, Camarines sur Site B: San Andres, Catanduanes Path length: 59 km Modulation: QPSK
Site Information
Longitude Latitude Site Elevation (Above Mean Sea Level)
Low Band
High Band
Site A 123 31’ 22.5”
Site B 124 31’ 52.5”
Units DMS
13o 34’ 3”
13o 38’ 15”
DMS
100.00
100.00
m
o
o
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Tower Elevation (Above Ground Level) Azimuth From True North
100.00
100.00
m
82 o 21’ 49.78” NE
97 o 31’ 31.6” NW
DMS
Site A 32.00 -86.00 0.60 0.16 0.50 37.50 0.50 0.50
Site B 32.00 -86.00 0 .6 0 0 .1 6 0 .5 0 37.50 0 .5 0 0 .5 0
Units d Bm d Bm dB dB dB dB dB dB
Site A 145.81 0.36 11.15
Site B 146.14 0 .3 9 10.11
Units dB dB dB
Site A 46.87 90.00 46.87 46.8685 35.7185
Site B 46.54 90.00 46.54 46.5386 36.4286
Units dB dB dB dB dB
Site A 99.999961 99.99949 99.999
Site B 99.999956 99.99955 99.999
Units % % %
Equipment Information Transmitter Output Power Receiver Input Threshold Waveguide length Waveguide loss Connector loss Antenna Gain Antenna Misalignment loss Wet/Frozen Antenna loss Path Losses Free Space Loss Oxygen Absorption Loss Rain Attenuation
Fade Margins Thermal Fade Margin Margin Dispersive Fade Margin Flat Fade Margin Effective Fade Margin Rain Fade Margin
Path Reliability Unfaded Reliability (one way) Rain Reliability (one way) Link Reliability (Duplex)
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2
Tower
The medium tower has the following physical properties:
•
Maximum height - 104 m
•
Parallel section - 10 m
•
Parallel face width - 1 m
•
Footprint for 104 m tower - 13.7 m
•
Tower heights – in 2 m increments up to 60 m, thereafter in 4 m increments up to 104 10 4 m
Foundation Designs
Tower Height
Concrete Volume
Reba Rebarr Exca Excava vati tion on Back Backfi fill ll
(m3)
(kg)
(m3)
(m3)
30
12
900
24
12
36
17
1258
33
16
40
18
1350
36
18
46
19
1078
50
31
50
26
1350
57
31
56
32
2242
60
28
60
41
3075
82
41
64
45
3375
90
45
72
48
4452
126
78
Antenna Loading Capacity Tower capacity of 92 m tower under the following loading conditions: Maximum survival wind speed
77.77 m/s
Antenna loading
10.5 kN or 6 m2 over the to 10m
2
2
2
Equipment Shelter
2
2
2
2
2
2
Building Description
Framew Framework ork:: The buildi building ng shall shall have a comple complete, te, intern internal, al, self-s self-suppo upporti rting, ng, structural steel frame which does not rely on the exterior panels or roof cover panels for any of its structural strength or framing. The building framework shall include 8 to 16 gauge, cold-formed, galvanized steel structural members. Building framework to have a flush wall, post and beam format with girts and purlins, and full trusses on both endwalls which easily allows for future expansion and/or modifications. Wall and ceiling structural support system are to be designed to provide load carrying capability for anticipated equipment loads using 16 gauge galvanized steel hat channels behind liner panel for reinforcement as needed, with locations shown on approval drawings. Roof to have 8 gauges to 14 gauge gaug e solid web hot rolled steel trusses.
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Insulation: Exterior walls shall have a minimum of 3.5”, fiberglass batt insulation and a vapor barrier. The ceiling shall have a minimum of 6” cellulose insulation and a vapor barrier. In addition to the insulation in the walls and ceiling, an additional 1” cellulose insulation blanket shall be installed over the entire building framework and under the exterior wall and roof panels, as a thermal break. The insulation system shall provide a minimum of R-19 in the walls, R-24 above the ceiling, and R-30 in the floor. Cellulose to have a minimum flame spread rating of 5
Roof: A roof pitched 1 inch in 12 or greater shall have a covering of overlapping, 18 gauge, G-90 galvanized, ribbed steel panels with a baked-on Kynar 500, PVDF resin based finish in manufacturer’s standard colors. Overlapping roof panels shall be installed with appropriate self-tapping fasteners with integral gaskets. A roof with a pitch of less than 1 inch in 12 shall have a roof covering of mechanically-seamed, 24 gauge, StandingSeam Roofing, with a minimum seam height of 2”. Standing seam roof panels shall be of Galvalume Galvalume steel, with a baked-on baked-on Kynar 500, PVDF resin-based resin-based coating coating and shall have no visible fasteners on main run. Roof to include a matching, die-formed ridge cap, and a fully supported 3” overhang. Properly sized attic space ventilation shall be provided.
Exterior Walls: The exterior walls shall be 18 gauge ribbed G-90 galvanized steel panels panels with with a baked-o baked-on n PVDF PVDF resinresin-bas based ed finish finish in manufa manufactu cturer rer’s ’s standar standard d colors colors.. Exteri Exterior or siding siding panels panels to be overlap overlapped ped and instal installed led with with approp appropria riate te self-t self-tapp apping ing fasteners with integral gaskets, and shall be removable without any disturbance to interior panels. Butted seams are not allowed. All openings in walls are to be structurally framed,
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sleeved, trimmed, and provided with external drip caps. Repair or replacement of exterior panels must be able to be done entirely from outside.
Exterior Trim: The exterior trim package shall include stepped or boxed eave, rake, fascia, base, corner, jamb, and header trim in, 26 gauge Galvalume material with owner’s choice of standard KYNAR colors.
Interior Finish: The building’s interior walls and ceiling shall be lined with flushfit 22 gauge, roll-formed liner panels, with concealed fasteners and a baked-on White polyester finish over G-90 galvanized substrate. The building interior shall feature a complete matching trim system including base, jamb, header, and ceiling trim
Interior Dimensions: The building’s finished interior dimensions shall be no less than 10 ½” in width and length from the exterior dimensions shown on the drawings. Minimum floor to ceiling dimension shall be nominal 10’.
Fasteners, Adhesives, and Sealants: The fasteners, adhesives, and sealants utilized shall be of types approved for use on this type of structure as required by the appropriate agency or governing body, as covered in section 1.02 of these specifications.
Closures: Matching, pre-molded, closed cell elastomer closures provided by the siding and roof panel manufacturer shall be installed according to the manufacturer’s recommendations at the eave line, beneath the roof panels, and where the trim meets the wall panels.
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Station Layout
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Conclusion
In desi designi gning ng a micr microw owave ave commu communi nica cati tion on link, link, the the foll followi owing ng shou should ld be considered; choosing appropriate frequencies which may be used for a specific distance, path terrain conditions, factor that affect microwave signals and the reliability of the link. In a long haul, the proper of the transmit equipment should be high enough in order to attain much higher reliability. It is more difficult also to attain a higher reliability in an over water link because of higher reflection coefficient, and when the path length is increases because of the increase in value of free space path loss.
The size of each Fresnel Zone varies based on the frequency of the radio signal and the length of the path. As frequency decreases, the size of the Fresnel Zone increases. As the length of the path increases, the size of the Fresnel Zone also increases. A Fresnel Zone radius is greatest at the midpoint of the path. Therefore, the midpoint requires the most clearance of any point in the path.
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APPENDICES
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REFERENCES
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BOOKS:
Fundamentals of Microwave Communication with planning gu ide By: Manny T. Rule Electronic Communication System, Fundamental Through Advance By: Wayne Tomasi
INTERNET SITES:
www.andrew.com www.globalspec.com www.commscope.com/andrew/eng/product/towers/index.html
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