eed RNS — TERRESTRIAL MICROWAVE AND SATELLITE COMMUNICATIONS 1 AAssingle transmission path from ‘Terrestrial Communications. Se Ga eee transmitter to receiver. | ro 2. Itis a receiver and transmitter placed ‘back-to-back or in tandem with the system, . A. Repeater ' 8. LMDS c. MMDS D. Transponder Hop ' Sle transmission path fom transmit 6 saree emgage i ‘A. Ground wave propagation B. Sky wave : Requirements for Terrestrial Cjeesceeere eoeiaion Communications ionospheric propagation ‘+ Signals follow a straight line or Line- ‘of Sight path, + Signals affected by free-space attenuation and precipitation, Microwave Repeater ‘+ Itis a receiver and transmitter placed back-to-back or in tandem with the system. ‘The repeater station receives the signal , amplifies and reshapes it, and then transmits the signal. Relative Curvature Sragh'Beam PERGMC = —s Beyond Traditional ECE Review www-percde-com xRN: Earth Bulge ‘The number of feet or meters an obstacte is raised higher in elevation owing to the curvature, Curvature | Fats a a ‘© equivalent earth radius factor ‘+ Defines the degree and direction of bending Rft_o.04865e° ner | |= Wweeamaovs 370m | & nea Fresnel Zone Derived from electromagnetic wave theory that a wavefront has expanding properties as it travels through space. TERRESTRIAL MICROWAVE AND SATELLITE COMMUNTCATIONS 4, What s the effective earth's radius when Ns= 3007 ‘A. 8500 km B. 7950 km ©. 7270 km 1D. 6370 km 5. IFNs =250, determine the earth radius k-factor. A123 8.129 6.133 D198 6. A line-of-sight radio link operating at a frequency of 6GHz has a separation (of 40 km between antennas. An obstacle in the path is located 10 km from the transmitting antenna. By ow much must the beam clear the obstacle? A116m B12m C.15m Dom Pine receiver towers have equal height. fees eran teria eaieasrae me cae ie ugth “Jean. Rep hel + citar pblareaation dL om Sota Pl A + ivton or “ABH og au, dont Abn ran (vlog P abi tabi tHhogte PMY Gey anes PERCDG —eyond Traditional ECE Review www.percde-comeRe AN: Path Calculations EIRP Defined as the power radiated by an antenna in its favored direction, taking the gain of the antenna into account as referenced to the Isotropic radiator. [EIRP-PG, Free Space Loss (FSL) ‘Loss incurred by a electromagnetic wave as it propagates in a straight ine through a vacuum ‘with no absorption or reflection of energy from nearby objects. [Eis = 32.4 2070055 Fama #20100 Gg [Ere = 928 BOT Tre? 2010s Fa > Engisn Sjsom [Ere = 3687 20100 Towa *2O10e [Eos = 98:6 7 201000 lone #2010050 al Isotropic Receive Level (IRL) ‘The RF signal level impinging on the far end receive antenna as ifit were an isotropic antenna, [TRL y, = EIRP — FSL) Received Signal Level (RSL) Itis simply the level of signal at the receiving end of the transmission, Received Signal Levol (RSL) in Ber Th 1G; bis Gn tn [FSC Pecos PERCoC TERRESTRIAL MECROWAVE AND SATELLITE COMMUNICATIONS 8 Amicrowave communications system, space loss calculation formula is: A. 92.4 + 10logF + 20og0 B. 92.4 + 20l0gF + 20090 ©. 94.2 + T0logF + 20!0g0 D. 94.2 + 20!0gF + 20!0g0 98. Whats the free-space loss, in dB, between two microwave parabolic antennas 38.0 kilometers apart operating at 7.0 GHz? 145.6 dB 8. 135.5 dB C. 138.5 B D. 140.89 48 10. Whats the effective radiated power (ERP) of a repeater with a 250 W transmitting power output, 3 dB feedline loss, 4 d8 duplexer loss, 5 6B circulator loss and feediine antenna gain of 20 dB A. 1576.99 W B. 1572.21 W ¢. 1571.89 W D. 1573.63 W at Ae nite pee tke ices convert wre, WwW ThoPmabe feprenonur Bhewnes beplon kes base Beyond Traditional ECE Review www-percdc.comSS —t—t—i‘“—CS— 3s ke et Per enenee 4__RNS— TERRESTRIAL MICROWAVE AND SATELLITE COMMUNICATIONS, CCarrier-to-Noise Ratio (CIN) 411. Space diversity transmission means itis simply the ratio of the Receive Signal trenemiting and receiving on Level (RSL) and the Noise Power. ‘A.two oF more diferent frequencies B. two or more identical frequencies © (4B) = RSLan - Pear . two or.more antennas operating on N as ‘wo different frequencies D. two or more antennas operating on Fade Margin the same frequencies itis the attenuation allowance so that anticipated fading wil stil keep the signal 12. A transmitter and receiver operating ‘above spectid minimum RF input. ‘at 6 GHz are separated by 40 km. How much power (in dBm) in Roceiver Threshold delivered tothe receiver ifthe ‘The minimum wideband carrer power at the ‘ransmitte has an output power of input to a receiver that will provide a usable 2W, the transmitting antenna has a baseband output ‘gain of 20 dBi, and the receiving antenna has a gain of 25 dBi? This is dapendent on: ‘A. -59.8 dBm ‘+ The wideband noise power present at B.-62.d8m the input of the receiver C.-82 48m +The noise introduced within the D.-72d8m receiver «The noise sensetivity ofthe baseband 13, A ship-to-ship communication system detector is plagued by fading. The best solution seems tobe the use of Diversity e Diversity suggests that there is more than one ‘A, a more directional antenna transmission path or method or transmission B. frequency- Vek where Cinirae ple 7 bo cola ue A = 42241.0079 @ = semimajor axis (km) Pola troy Une P = mean solar earth days Satellite Orbits + Eliptical Orbits = Gircular Incined Orbit * Circular Orbit with Zero inclination PERGDG = Beyond Traditional ECE Review wuw-percdc-comPERCoc oneal 8_ANS — TERRESTRIAL MICROUAVE_AND SATELLITE COMMUNICATIONS: Orbits of Non-Synchronous Satellites = Prograde or Posigrade with + Ravogrede megan ..¢ Satellite Orbital Patterns Inclined Orbits + Equatorial orbits = Polar orbits Satelite Elevation Categories LomEarth Orbit (LEO) 0 1-2.5GHz ‘Medium Earth Orbit (MEO) © 1.21.86 GHz + Geosynchronous or Geostationary Orbit (GEO) © 218GHz © Sometimes referred as Clarke orbit or clarke belt. Satelite Type Height (mi) Rotation Period | leo 100-300 ‘Angle of Elevation Itis the vertical angle formed between the direction of travel of electromagnetic wave radiated from an earth station antenna pointing directly toward a satelite and the horizontal plane. * Angle of elevation less than 5 degrees is avoided Azimuth * Itis the horizontal angular distance from a reference direction, either the southern of ‘northern most point of the horizon, + Azimuth angle is defined as the horizontal pointing angle of an earth station antenna, or Di Itis basically he distance of the satelite from an earth station, Beyond Tradi 26. Satelite that are 22,000 miles above the surface ofthe earth is called ‘A. Geosynchronous orbit B Clarke belt C. Clarke orbit D. any ofthese 27. The availabilty of a geosynchronous satelite AShrs B 24hrs ©. 14 hrs, D. 100 hrs 28. Itis the vertical angle formed between the direction of travel of electromagnetic wave radiated from ‘an earth station antenna pointing directly toward a satelite and the horizontal plane, A. Angle of dectination BB. Angle of inclination ©. Azimuth, D. Bearing 29. The minimum angle of elevation is A.3dog B.5 deg ©. 10deg D: 100 cagee ened RNS — TERRESTRIAL MICROWAVE AND SATELLITE COMMUNICATIONS 9 Range or Distance [eam = IRs MF RE cos? A Rain) Satellite Antenna Radiation Pattern The Geographical representation of a satelite antenna’s radiation pattem is called a FOOTPRINT or FOOTPRINT MAP. Spot and Zonal Beams + The smallest beams. ‘Spot beams concentrate their power to very small geographical areas, + Spot and Zonal Beams blanket less than 10% of the Earth surface. Hemispherical Beams Hemispherical down-link antennas typically target up to 20% of the Earth's surface. Earth or Global Beams Radiation patterns of earth coverage ‘antennas have a beamwidth of ‘approximately 17 degrees and capable of ‘covering 42% of the Earth's surface, Launching of Satellites ‘Apogee kick motor + This is fred to place the satelite to its final orbit: Station Keeping The process of fring the rockets under ground ‘control to maintain or adjust the orbit Attitude control Positioning of the satelite for optimum performance, PERCOC Beyond Tradi 30. Calculate the length ofthe path toa geostationary satelite from an earth station where the angle of elevation is 30 degrees. A.55x 103 km B.13x 10" 3km C.23x 1043 km 1.39% 1083 km 31. Telephone communication takes place between two earth stations via a satelite that is 40,000 km from ‘each station. Suppose Bil, at station 4, asks a question and Sharon, at sation 2, answers immediately, as ‘soon as she hears the question. How much time elapses between the end Cf Bill's question and the beginning of ‘Sharon's reply, as heard by Bill? A.0.26 sec. B32 sec C052 sec D. 16sec 32. The process of maneuvering a Satelite within a preassigned window is called ‘A Telecommand B Telemetry . Control D. Station keeping eT 012, |(o4oo. height ey 1 ECE Review wuw.percdc.comenone 10 _RNS — TERRESTRIAL MICROWAVE AND SATELLITE COMMUNICATIONS Satellite Velocity 33. Find the velocity and the orbital — period of the satelite in a circular q 4 4x10" Orbit 500 km above the Earth's aTeaacr | surface (a + 6400) A 16 hrs where: B.32hs C24 hs v= velocity fra Beane {d= distance above earth surface (km PO oe er dB looks at a sky with a noise Declination Angle temperature of 15 K. The loss oe sie eS between the antenna and the LNA aes ( Rsint ) input, due to the feedhor, is 0.4 dB, arctan| Sn and the LNA has @ noise temperature HER tecost) (of 40K. Calculate the G/T? where: A 13.4 48 | : B 3908 R = radius of the earth sua |H= height of the satellite above the earth) D.11.248 |L = earth-station latitude: J 35. A satellite transmitter operates at 2 4 Figure of Merit GHz with a transmitter power of 7W_ | See and an antenna gain of 40 dBi. The | [ @rr(@8) = 6, (68) - 10109 (T, + T.) receiver has antenna gain of 30 dBi, and the path length is 40,000 km. Ise : ler (an) = Gas ti sion CSRS evo Cael te sigral strength atte fs a) econ atine ata ston Socen Sram ae ee eee ah : Lass pet o todow “Peng EET or bilenaipton ag? Og Fstyo” bse +S ipa dn Be Dandulath oh be The? copner qe oni ratip ap = offere Tap maakdy oer L = free spur Web ait i 4 poy & PERCne “beyond Traditional ECE Review www-percdc-comeon RNS — TERRESTRIAL MICROWAVE _AND_SATELLTTE COMMUNICATIONS A fading HOMEWORK B jiter G. intermodulation distortion Terrestrial Microwave D. phase distortion 36. Assume a frequency range of 41. tis the diference between the 405.0125 MHz to 405.0875 MHz and nominal output power of transmitter 25 kHz channeling plan, Determine {and the minimum input power the center frequency of the second required by a receiver. ‘channel from the lower limit. ‘A. System gain ‘A. 405.025 MHz B. Fade margin 8 405.050 MHz C. Free space loss ©. 405.075 MHz D. Receiver threshold 405.030 MHz 42. Aline-o-sightraci link operating at a 37. Atype of diversity where it simply {trequency of 6 GHz has a separation modulates two different RF carrer ‘of 40 km between antennas. An {frequencies with the same IF ‘obstacie in the pathis located 10 km inteligence, then transmitting both RF {rom the transmitting antenna. By signal to a given destination how much the beam clear the ‘A. space diversity obstacle? 8. polarization diversity A 134m . frequency diversity B 121m D. null diversity 109m D.11.6m 38. Which ofthe following provides the most reliable transmission? 43. Ina microwave system, the antenna A. Quad diversity 3205 a sky temperature of 120 K, and B, Polarization diverity the antenna feediine has a loss of 2 C. Hybrid diversity 4B. Calculate the noise temperature D. Frequency diversity of the antennayteedlne system, referenced to the receiver input 39. A type of protection switching A195 K arrangement where each working 8. 182K radio channel has a dedicated ©. 168k backup or spare channel 0. 156K A diversity protection 8. hot standby 44. A receiver has a noise figure of 248. polarization protection ‘Whats the equivalent noise D. protection standby temperature? 135K 440° This term applies to propagation B 182K variables in the physical radio path C. 168K which affect changes in the path loss 156K between the transmitter at one station and its normal receiver at the other station. PER@DE — Beyond Traditional ECE Review wuw-percdc.con(oe ened 42_ RNS — TERRESTRIAL MICROWAVE AND SATELLITE COMMUNECATIONS 45. One of these is not the cause of fading ‘A.multipath reception B. ducting, . attenuation due to rain . amplification of transmitted signal 46. In space diversity, the two antennas should be separated by A. 120 wavelengths B. 150 wavelengths ©, 60 wavelengths . 200 wavelengths 47. In radar communications system, \hatis the total elapsed time from the instant of intial transmission to the reception of the echo? ‘A.6.18 microseconds B. 18.4 microseconds . 12.38 microseconds D. 5.37 microseconds Communications, 48, A satelite receiver has a noise figure: of 1.6 dB. Find the equivalent noise temperature A 144K B 289K ©. 129K D.406K 49, Find the orbital period of a satelite in ‘a circular orbit 600 km above the surface of the earth. 1.615 hes 8.58 hrs 6.58 hrs D. 16 hrs 50. Calculate the angle of declination for ‘an antenna using a polar mount at a latitude of 45 degrees. A. 3.2 degrees B.13degrees C.42degrees D.681 degrees PERCoc Beyond Traditional st. 53. 56. 56 The GCE-transmit subsystem in earth station performs what function(s) ‘A. Up conversion B. Modulation and muttiplexing ‘C. Demadutation and demultiplexing . Down conversion {As the height of a satelite orbit gets lower, the speed of the satelite A increases B. decreases remains the same none of these ‘The satelite communications channels in a transponder are defined by the ALNA B. Bandpass fiter C. Mixer D. Input signals, Batteries are used to power all satelite subsystems A atalltimes 'B. during eclipse period C. only during emergencies D. any of these ‘The main power sources for a satelite are A batteries 8. fuel cells . solar cells D. thermoelectric generators Its a technique that allows two sets of transponders to operate on the same frequency. ‘A spatial isolation B. double conversion yaw D. frequency reuse TT ECE Review www.percdc-comCommunic ANS — TERRESTRIAL MICROWAVE _AND SATELLITE CONMUNICATIONS 13 ——__—_—_—_SR——E_ —E TIONS 57, In satelite system, focused beam of 68. A postional tolerance of 0.1 on a energy that covers @ relatively small geostationary orbits equivalent to an sea on eath, produced bya high fre dstance of gain antenna on te satelite Avakm 2 spol beam 8.200 km B goer beam 300 km G footprint D.240km D. monochromatic beam 64, Which par of transponder converts 58, In satoitecorimunication the received signal io another lower continuously adjusting the postion of frequency? 2 directiorial antenna on the ground, ALLNA fo that talvays points at the salle, B.HPA A tracking ere 8. downlink D. Mixer ©. uplink D. toking 65. A ground station is operating fo a geostationary satelite at 2 9 degrees 59, How does spatial isolation technique angle of elevation, Caleuite the in aatlite communications avold round-tip me between ground interference? station to saelites ina geostationary 1 Use of ferent polarty antennas one 8. Use of diferent iypes of antenna 2456.45 ms C. Employment of highly directional B. 275.58 ms spotbeam antennas ©1377 ms Use of ow gain antennas 5.12609 me 60, Typical bandwith of a 66, Satelite ot around the ear are communications satelite either: A. al are ocular B. el are RioMHe lipticalC. they ae eer creular or 500 Mz elliptical: D. none ofthese tree. C 4omee AD D.25 Mie 38 ce 61. Satolites that rotates around the Ba eatth in ow-alitude eliptical or Circular patorn 67, Referred to as a function andlor ‘k. Geosynchronous satelite design of @ double conversion ®. Nonsynchronous satelite satelite C. Progeade ‘A Demodulate its uplink signal to D. Apogee recover is baseband signals and use them to domodulao a 62) How many satlites does the GPS Sownink transmitter Sytem consists? (Fogenerative transponder). ne 8, Equipped witha singe mixer that B24 corvers al satelite channels 63 within the (500MHa) bandwictn D.60 Simutaneously to their downlink fequony (broadbandtransponder) PERGDC = Beyond Traditional ECE Review www-percdc.com14_ RNS isons ROU ESTEE AS TERRESTRIAL MICROWAVE AND. SATELLITE COMMUNICATIONS. . Has individual LNA, HPA, mixer | Sovier TS ‘the firgr. fe use DomsaT and bandpass fie for each 1. L2sheoenis channel 0 1-2: (channelized transponder) 3 ~) 7h ms eee WO 12-Ap¥Gke GK i ls RO estasis maned’ || Geo, Zot ete A) field strength over the projected sore aos \ridtun bas ote Petes Radio monitoring (eat) BN f thes sa > adi ound Laser wants ate now used lo D. Radio survey |. Assume a frequency range of ‘401,000 MHz to 401.050 MHz, if you ‘apply 25 kHz channeling plan, ‘determine the center frequency of the first channel from the lower limit. ‘A. 401,025 MHz B, 401.0625 MHz 6, 401.0125 MHz 1D. 401.010 MHz 70. Occurs when the microwave beam is. at point of grazing over an obstacie. A difraction B. absorption . refraction D. reflection 71. IF repeaters are also called ‘A. Heterodyne repeater B. Basoband repeater C. RF repeater D. AF repeater 72. Itis the figure of merit used to indicate how much the signal-to-noise ratio deteriorates as a signal passes through a circuit or series of circuit. A. noise factor B. fade margin CC. cartiero-noise ratio D- relabilty factor Beyond Traditior eatelik’s 1 Communicate: 8 eq mas. Spurnik sev long cect Hue edith, (ee enoryy ce Zeminnk Chaya Sj Une Saloni — nal ECE Review www-percdc.com