microwaves_handout1.pdf

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Microwaves * pertains to wavelengths in the microwave sBectrum, ranging from30 - 0.3 cm and coresponding to frequencies-ianging from 1 to 100

GHz.

A. ADVANTAGES OF RADIO LINKS OVER CABLE NETWORKS:

1' Radio links are favored over cable networksfor communication over roughor inaccessible terrain.

2' communication over water can frequently be accomplished economically inspite of the radio reflecting characteristics of water.3. Insta[ation time pressurei frequenily favor radio sorutions.4' Property-acquisition problems tend to b9 minimized, since radio systemrequire a small plot every 30 to 50 Km co*pured io trt" need for acontinuous right of way for cables.5' Systems Gan be reconflgured geographically to meet changing needs,

whereas, it is almost never practiial io retrieve a buried cable.6' Occasionally, restoration of communications after a natural disaster is asigniflcant mission for microwave radio,

B. DISADVANTAGES OF MDIO UNKS:

1' Radio transmission through the lower atrnosphere is subject to propagationimpairments, which result in sporadic occurrences of transmissiin iu[ages.However, accumulated experiences has provided statistical models todescribe these conditions as they affect the radio si=t *; the suceessfuloperation of tens of thousands of microwave hops attest to the satisfactoryguidancewhichthesemodelsprovideforsystem.design,

2' Limited to short distances (LoS), there is a neeO- for relays for longerdistances.

C. Differences between microwave and HFIVHF:

Band TransmissionIrtedium

Antenna Used Transmitter toAntenna SignalFoflfl

OparatingfrequencyandUfavelenoth

HF/VHF Wire Dipole Voltage orCurrent

30 - 300 Mhz10m-10cm

Microwave Waveguide Parabolic/Horn Electromagneticvvaves

1.0 - 30 Ghz30 - 0.3 em

Microwave is distinguished from other radio applications by its frequency range andby the use of high directive antennas, These distinguishing featui"s occur in bothterrestrial and satellite systems but the design problems-are

diffierent enough towarrant separate engineering treatment.

Terrestrial applicdions are primarily of a point-to-point nature and use the frequencyrange from about I to 40 Ghz,



y=

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D. FREQUENCIES USED IN MICROWAVE COMMUNICATIONS (1 TO 40 Ghz):

1' Microwa.ve frequencies are used for communication systems because it ispractical to focus the radio energy into a beam and thus contrite i-nigr,e,percentage of that energy at a receiving location inin would be the case forlower frequencies,2' spectrum availability;

at thelower

frequencies where non-directionalantennas are desired for broad coverage system, the requests for spectrumallocation have beel very great, as a result, only nurio* iprii", urenormally licensed; thus it is practical to build'systems to handle largequantities of voice, video and data traffic, Spectrum demands in a lowfrequencies are high; so assigned bandwiath rir each station is narow toaccommodate as many stations as possible.

3' Syste.T.s operatjng in the higher frequency bands (in the vicinity of 11 Ghz)can utilize smaller antennas and do not require as much terrain ilearance.4' In densely, populated areas and on t,igrt-tramC intercity i"uiJi, lowfrequency channels may not be avaitibh; but atmospherii-iauseopropagation impairments, particularly rain attenuation, inirease

substantially at frequencies above 10 Ghz.5. usage developed first at the lower frequencies, in the vicinity of 2 Ghz to 4Ghz because of the.availability of hardwa.e; ihe technical factor of b"tt".beam focusing and. the regulatory factor of spectrum shortage bothmotivated an upward movement of frequencies utilized.

E. CHOICE OF FREQUENCY BAND FOR A NEW SYSTEM:

1' The availability of frequency assignment must first be investigated; a newlyg:f:H^:I:fT., ,-1.

f"g.ui."d o coordinate the choice of operatinsfrequencies with all other licensed systems within rz5 mi[i

"f

*u.rriJ*iio;

L:*: :_gj*$frdinarion is facirtated by companies speciatizing inmaintaining2, If spectr:urn

rquencies and locations already licensed.5 not a limiting factor, the choice can I

the basis ofvicinity of 3, #

the choice can be made onIilability. As a practical matter, frequencies in the

are most commonly used for long-haul, multi_hop'emely heavy rainfall.ystems or in

F. LFTTER DESIGNATIONS FOR I*ffSROWAVE MNDS:

BAND FRmUNtr RANGE (Ghz)

0.225 - 0.390

0,390 - 1.5501.550 - 5.2003.900 - 6.2005.200 - 10.90010.900 - 36.00036,000 - 46.00046,000 - 56.000s6.000 - 100.00

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G. ADVANTAGES OF T\4ICROWAVE COMMUNICATIONS:

I' targe information handring capacity (2s6 - 9600kbps)2. High retiabitity through airersify telf,niqu"s3. Lower poygr consumption (excbpt t.opoi4. Carry wideband circuits for high ipeeO aita / high quality voice channelsq, High degree of privacy

- easfOatb encrvption6' could be fitted with anti-jam equip#6nt, adaptive modems and otheraccessories7, Fonrard error correction and hifless switchingB. Microprocessor-controiled pre-detection iomIining

H. ROLE OF MICROWAVE IN SYSTEMS:

The usual function of a microwave system is to serve as an interconnectingmedium for other equipment, which is considered the "reai,, communicationsystem.

Microwave is commonly used to convey multiple teleBhone conversations

from one location to anotheri possibly vii one or more intermediate locations orsites' The telephone users do not expect to experience crosstalk frsm othertelephone conversations sharing the same microwave equipment / system. othersources of noise or interference due to the microwave iyrr"*- should also beimperceptible.Microwave is also used to interconnect data services (computer terminals,keyboards, CRJ, displays, etc.) with control and monitoring-derices at remotely

located sites along a pipeline.For the user, the microwave interconnection should he transparent portion

of his total system; to achieye this:The eguipment specifications must be consistent with transparency the system,The equipment

must meet or exceed its technicil ferformance ipdcirication.The microwave system must be designed to mari effective ,s" oi tne equipmentspecifications.

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I. APPUCATIONS OF LOS MICROWAVE

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6,7.

Psint to point links as a backbone or tails of large networks for commoncarriers, specialized common carriers and private g6vernrnent entittes.Point to multipoint systems for TV, telephony, dati or various mixe$ thereofTransport of TV or other video signals such'as CATV head end extension,broadest transport and studio-transmitter- link (STL).Specialized digital and digital data networks. :

Pow.er.and pipeline companies for the transport of telemetry, command andcontrol information.Air traffic control center interconnectivity.

lhort haul {short distances) applications such as linking offlces andbuildings in congested urban areas; final connectivities for cemmoncarierc/ specialized common carriersl tails off fiber optic trunks.Military applications: fixed point to point, point to multipoint andtransportable point to Boint

8.



F tfiese applications are now being tgr1pcrcrl by fiber opuc links. Fiber optic is

:n "f,*::,ulq,p:[d::

-c3ryioeraorvs'ead inrormiiio"'o"nooidth. Fiber,;ffi;l;u;#T;onstruction activities.

Common services:1, Military2, Operational fixed

3. STL4. Common carriers5, CATV STL6, CARS - community antenna radio service

]. TYPES OF STATIONS:

1, Terminals points in the system whereoriginated or terminated.

baseband signals are either

2, Repeaters points in the system where baseband signals maybereconfigured or where RF carriers are simply "repeated" or amplified.

Satellite VS Microwave linklEarth station - satelliteTerminal stations - microwave repeater

NorE: 1. A terminal station maybe eonnected to several links; a repeater works injust one chain,2. An earth station works with one stellite; a sateltite works with anynumber of earth stations.

K. TRANSMISSION METHODS

A, Advantages of Analog lrlicrowavel1. In small mediurn sized systems: superior voice channel performance2. For most system sizes: performance advantage for'roi.* channel data

modem users3. Given sirnilar bandwidth and the voice channel capacity: much higher

system gain4' Give similar system gain and bandwidth; higher voice channel capacity

B, Advantages of Digital Microwayes:No difference between voice and data threshold to considerNo baseband slot allocation difference to considerPerformance advantage for. voice userc in large systems and for high speed(T-U data.Given similar bandwidth and voice channel capacity: much higher data or T-1 capacity.Given similar data or T-1 capacity: much rnore bandwidth efficiency for dataor T-1 transmission.Given similar system gain and bandwidth: higher data or T-1 capacity,

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rn Digital microwave system, both voice and data channels are affected similarlyy signal fading, in contt di to the differen.""in voice ir,ann"r ano data channelerformance in an.analog system wrrere voiie-ininner perfo*nani".**uins usabre whenhe received signal tevel nai faded below tnelerJ which wiil iause data channet outage.he digital.-system equivalent to basebanJ'r."qu"ncy slot allocation, which maj.esbsolutely no diffeience in'cfrannei O"*qffici, unlike the analog FM systems wherehe highest baseband frequen.virot usuafly has the worst noise,

L. CATEGORIES OF MICROWAVE:

A, LOS Communications;1' Use row transmit power and highry-directionar antennas2. subject to earth burge and othir ooit.u.tions3. Maximum distance of singre rink: 3oio 50 statue miles4, Operates at VHF band and above

B. Tropospheric Scatter Communications:1' Requires very high-powered beam of electromagnetic energy (1

to 10Kw)2. Beyond LOS / over the horizon .o**uni."tions3. Uses refractive properties or tropoirreiic turourences4' operates over ohstructed_ q"th qr nJvono Los by beaming signats towardsthe troposphere at about 15 Km from ihe earth.5' provide reriabre communications up to +oo rtutue miles6. uses parabolic antennas with diameters of 4"5, g or 1g meters7 ' operates between 300Mhz to 10 crri itrrough the common volume rt'

Iff*t?*[r:nvolume is determined by the anrenna iize and scartering

M. FACTORS AFFECTING MICROWAVE ENERGY:

1' Fading - variation of field strength caused by the changes in transmissionmedium i.e. atmospheric conditidns and wave direction2' Refraction - change in direction aue to changes in transmission mediumdensities, temperature, Bressure and water vapor,3' Absorption energy tiss due to abiorption of waves by atmosphericelements such as rain, snow, oxygen, crouds ana vapors,-4' Diffraction the chang.e in'irspagation

dlrectisn- of waves due todifferences in density / velocity oi *"Oiu*,5' Attenuation - a decrease in the intensity of energy due to spreading of, energy transmission rine rosses between two antennii.

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6. Reflection - occurs when waves strike smooth surfaces

7' Ducting and thermal inversion l papped waves uouri* back and forth in aduct caused hy temperature and truririoitv inversion, i.e. ir,i.t*er air is on topinstead of being at the bottom,8' Earth Bulge - earth's curvature presents "LOS,, obstruction and must becompensated using 4/3-earth radius for atmospheric fenOing of waves.



.l

SELECTION OF .SITES:I. Site Considerations:

1' A full description af each site by geographicar coordinates, political

id,f;n{,,;,:l:n,access roads uno- pnvri.ur 6oj6cts

-witnwhich it can be

2' Any unusuar weather conditions to be expected in the area.3' A description of the physicalinaracteristics or-ihe site, indicating themount of leveling required, removal or roo<{ tre", oi other structures..

mi,l"gi:?;lr[,,ll.rd.sit6 to uny'.o*merciat, mittary or privare airporr

5' The mean sea level elevation of the site at the recommended tower location' A full description or recommendation for .n u.i*rr'ioaa from the nearestmproved road to the proposed building location,7 ' sites wherein building- cobe .est.i.tioni maybe involved should be avoided.' rhe

l:ffijJ::ltionwhere commerciar eiectrii il;;. or suitabrl ,Ji"s"

s'[:i"j:l*::;..o**unication

is desired, rhe nearest tetephone facitity shoutd

10'Any other facts that can be determined at the time of the suryey, whichmight bear on the proposed construction.

II. Site Requirements;1' Terminal sites - locations of the transmitting and receiving antennas locationsof existing structures or terminal faciliiiei.

Consider the following :

€l' Height o-f existing buildings - is it possible to mount an antenna fixturewithoutfear of path.brockige by other buirdingsib. possibirity of future buildin{construction aton{ the pathc' structural adequatenessor tne building- ii ini.rrii fixtures are to bJnounted at the roof.

d, Future floor additionse' If the above considerations are not met, a separate tower on thebuilding lot maybe the solution.

LOS Siting procedures:

a' construct path profile chart using contour maps and profile charts,Use path profiling Software if availableb. conduct field inspection to determine ground suitability, antennaerection, equipment shelter buirding

-unJamount of clearingrequired.

c' use equipment such as: ,-["y radios, binocurars, surveyor,stransit, radio__a-rtimeters, DME,' ane.oid' nuio**t*.r, etc. usecompass or RDF for triangulation.

d, conduct aerial reconnaissance and take aerial photographs ifpossible, to determine accessibility or roaos, po*". lines and evadereflecting bodies of water, obstructions, navigationar hazards, etc.

i l:;::#,ffi' ;H".lP,'li, ,.x" :*:ff ISliffiXi*",:iJ;,g. conduct soir tests for structurar foundation;66".



2, Intermediate Repeater Sites:

Factors to be csnsidered:t'

#jffi?ioHeisht- take advantage of rhe naturat etevation ro ctear

b, Terain:obstructions - ttq vegetation,

buildings and other obstructions thatlock or absorb microwlvt;;ogy. pran requirements for obstructionemoval to ensure LOS.Reflection - smooth surface ma cause a second signar to refrect to theeceiving antenna. out_of-phasi signats ilttd;il rrOing or canceflationf desired signal. ptot. patti pi"nf" t" determinl ii"qu..y / existence oflearance between the .os raoio p;ih unJ li" te*ain. crearanceequired depends on the radius of the iirrl r[in"iior*.:;i:?.#:ilrenance

access is very importani,'Jn"..**s

road must be

The need of AC power of suitable voltage, also of telephone facilities andther utilities like water,

The possibility of interference, internal or externar to the system.]vne of ground / soil foundation on wnich to build the station.security requirements againJr iiregar intrusion ina Lnotage of facilities.avigational hazards poseO by tofiers to air transport.

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MICROWAVE coTII M u NIcATIoNsurcRowAvE - a term applied to those-radio frequency and wavelengths that are shortnough to have some of the properties of righi. (ii; 30 Ghz or so io o.s cm)

otherwiseknows as antenna gaindegradation,istneofthetroposcattervolume.Itisthedifference between free-space expected gain and its measured gain on troposphericscatter hop,

BEAIIIWTDIH - the measure of a unilateral antenna's directional properties of directivitymeasured from two points on either side of maximum radiation where field sfrengthdrops by 3 dB.

DIvERsrrY - is the u$e of redundant system to reduce the effects of fading. There arefew available methods of diversity - rpace, r*qr"n.y, polarization, cross band, andhybrid diversity.

FADE l'lAR'GrN - is the extra strength needed in order to assure that enough signal (30- 40 dB) reaches the-receiving antenna and must be available to iompensate for fades,It is the difference between field strength or $," level nor*"tty received and thethreshold level.

HoRrzqN ANGLE - the angle at which the antenna must be aimed to clear the horizon.

F9RWARD SCATTERTNG - a phenomenon whereby high-powered electromagneticwaves are refracted in a forward direction resulting'rroni

flie'ilrUulence caused hymoisture and eddies of wind current.

KI{rFE-FDGE qIFfRAGTroil - h* ability of a radio wave to be bent stightly over theedge of a sharp obstacle' A sharper 9dg. cuus"s less attenuation and at higherfrequencies, there are lesser diffraction effects,

I{UITfPATH TBSNSiIISSI9I{ - is the process when a signal takes severat paths inaddition to the direct path to go to a receiving antenna, by reflection and / or refractionof waves.

RADro p4TH - the actual path over which microwave signals are proBagated

R4DI9 HOBIZON - a point at which a radio path is tangent to earth,s surface,

sc+IrER AI{qLE - either of the two acute angles formed by the intersection of twopoftions of the troposheric scaHer beam (lower Soundaries) ta;gent to earth,s.surface.Keeping the angle small effectively reduces the overall path itteniation.

SGATEER voLUl{E - otherwise known as "cornmon vorumei the comrnon encrosedarea where two beams intercept.



ffi;rfir:?ghJffiffX.a horizontar ray exrendins from the radiation

THRESHOtD LEYEL - lowest signal tevel that wiH be intelligible at the radio receiverT'RQ?pF?HERrG' sqlITEB - scattering of waves due to differing hmperature and

fril;H:",rrTff%;lffirtropospnirii

r"v"'i resutins to different desrees or

I '.INDow - range of microwave ftequencies more easiry passed by the atmospherehan the others.



*rF

MICROWAVE FREQUENCIESTIIA,IOR BAilD DESIGNATIONS

B, DET4IIED IrlXCRowAvE SPECTRUM DESIGI{ATIONS

A.

0.225 - 0.390 GHz 133.30 - 76.90 cm0.39 - 1.S5GHz 76.90 - 19"37 cm1.55 - 5.20 GHt 19J7 - s.77 cm

.90 - 6.20 GHz 7.69 - 4.84 cms.20 - 10.9 GHt 5;t7 - 2.7s am10.9 - 36.0 GH, U.59 - 8.34 mmggo - 4s.0 GH, 8.34 - 6.52 mm46.0 - s6.0 GH' 6.52 - 5.36 mm

BAT{D FREOUEIUCY YYTIVELENGTT{

LDLt> - syu MHz 1_3? - o 760390

-468 Mr-{z

0.169 - 0.645 m456 - 510 MHz n64tr-ntrooLI 51O * zls Mu 0.588 - 0.413 rnLy 725 - 78O MHz 0.413 - 0.3&t m

ts/6V - gUU MHZ

-g.1B4- 0,333 m

900 - 950 MHz 0.384 - 0.315 mLK rlf,U - 155U MHz 0.315 - A.ZZZ mLf0.222 - 0.207 m

I+}U - 155U MH7 9.207 - 0,193 mSe 1.55 - r.es cui 19.37 - 18.18 cmSb

Str.e) - 1..u5 Gt-lz 18.18 - 16.21 cm1.85 - 2.Oo GHz

16.21 - 15.00 cm2.00 - 2.40 GHzSq 15.00 - 12.S0 cm

2.40 - 2.60 GHz 12.50 - 11.54 cmSy 2.60 - 2.7fi GHz 1 .54 - 11.11 cmSg Z,lU - Z.9U GHZ 11.11 - 10.34 cm5sSa

2.90 - 3.i0 GHz 10.34 - 9.68 cm5.IU - 3.4O GHz 9.68 - 8.82 cmSw 5.4U - 3.7O G14z q.82 - 8.11 cmSh

r E./u : J,gA GHZ 8-11 - 7 6Q nrn3.qo-6?n(;H 7.E9 - 4.84 cm

Sdr.YU - r+.lu Gl-{z 7.69 - V.L4 cm4.2A - 5.20 GHz

7.t4 - 5.77 cmXaXq

}.zu - 5.50 GHz 5-77-54{rrn5qN.E?ECLI- 5.45 - 5.22 cmXy u,/3 - 6.7t) GHz 5.a2 - 4.84 cm



Xd 6.20 - 6.25 GHz 4.84 - 4.80 cmxb 6.25 - 6.90 GHz 4.80 - 4.35 cmXr 6.90 - 7-OO GHz 4.35 - 4.29 cmXc /.oo - 8.50 GHz 4.29 - 3.53 cmXI 8.5O-QOOltl-lz 3.53 - 3.33 cmXS 9.00 - 9.60 GHz 3.33 - 3.13 cmXx

9.60 - 10.00 GHz 3.13 - 3.00 cmxf 10.00 - 10.25 GHz 3.00 - 2.92 cmXK 10,25 - 10.90 GHz 2.92 - 2.75 cmKP 10.90 - 12.25 GHz 27.52 - ?4.49Ks L7.25 - 13.25 GHz 24.49 - 22.64 mmKe 13.25 - 14.25 GHz ?,2.64 - 21.05 mmKc 14.25 - 15.35 GHz 21.05 - 19.54 mmKU 15.35 - 17.25 GHz 19.54 - 17.39 mmKt 17.25 - 20.50 GHz L7.39 - 14.63 mmKq 20.50 - 24.50 GHz 14.63 - L2.24 mmKr 24.5A - 26.50 GHz L2.24 - 11.32 mmm

26.50 - 28.50 GHz 11.32 - 10.52 mmKn 28.50 - 30.70 GHz 10.52 - 9.77 mmKI 30.70 - 33.00 GHz 9.77 - 9.09 mmKa 33.00 - 36.00 GHz 9.09 - 8.33 mmQa 36.00 - 38.00 GHz 8.33 * 7.89 mmQb 38.00 - 40.00 GHz 7.89 - 7.50 mmQc 40.00 - 42.00 GHz 7.50 - 7.14 mmQd 42.00 - 44.00 GHz 7.t4 - 6.82 mmVA 46.00 - 48.00 GHz 6.52 - 6.25 mmVb 48.00 * 50.00 GHz 6.25 - 6.00 rnmVC 50.00 - 52.00 GHz 6.00 - 5.77 mmVd

52.00 - 54.00 GHz 5.77 - 5.55 mmVe _ 54.00 r 56.00 GHz 5.55 - 5.36 mm



1.

2.

LrNE-OF-STGHT (LOS) COMMUNTCATTONS.. use low transmit power and highly directional antennas. Subject to earth bulge and other obstructionso Max distance of single link 30 to 50 statue miles. Operates VHF band and

aboyeTROPOSHERIC SCATTER COMMUNICATIONS

' Requires very high powered beam sf electromagnetic energy (I to l0 kw). Beyond LOS I over the horizon communicationsUses refractive properties of troposheric turbulencesoperates over obstructed path or beyond los by beaming signals towardsthe troposphere at about 15 km from the eartfiProvides reliable communications up to 400 statue milesuses parabolic antennas with diameters of 4.s, 9 or 1g metersoperates between 300 MHz to 10 GHz through the common vo{umeThe common volume is determined by the antenna size and scatteringcharacteristics,

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a

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LOS PROPAGATION

. LINE-OF-SIGHT (LOS) DISTANCE - the straight-line distance from theantenna to the horizon. Radio horizon extends beyond optical horizonresulting from refraction in the earth's atmosphere. Radio Horizon distancemay be calculated using the formulas:

,1-D\

LOS HORTZON prSTA{CF

The refractive index decreases with height above the earth,s surfacebecause of changes in atmospheric condition, i.e. humidity, temperature

orpressure.Changes in media density from high to low bends I refracts waves towardearth's surface, reducing earth's curuature and extending radio horizon,Refraction vary with atmospheric and climatic conditions.For average conditions, the direct path distance can be plotted as a straightline by increasing the earth's radius by a factor of 4/3 or 1.33 (K vary from1.0 in dry climates, to 0.66 in hot, humid climates)since the actual earth's radius is 3960 miles, the effective radius forcalculating the radio horizon is 3960 x 1.33 or s2B0 statue miles,

o

a



L"*H?:"r?: :i#:f: rl::,:T-req-uired to cover a siven tarse disrance whenffjg::"S.i:::';11:f

,:.I."^TT*iT-;;t^il;;ili';'i;lBi;JffiSX?

::::::,11l :'":.i:ti" Iink svstem o*i ir'*'Iim;"ilti.,.

ilH'::J:,j:ll""Hl;*i*j.r^1"^TI l Fiffi .[:ross ra rse stretches or water or

^between areas

separated by inaccessible terrain,3, Mav he ir"lo.atlrr crri$6.1 *a xr^ L-r, -

I*,lj,y^."rll.:T:.d to mebt totr-.onn.cting requirements of areas of towopulation density.

3: Hi:llITl".*?"*r.T^T::,iTf: *lrit?tes of another porfticar adminisrrarion.'ff$:';-:i:f,ff:lH,::::"op*i.out"-[iffi ;d;';#;'.f iHl;*Tl[t-ff i,T?ystem over the same route.

u' So?j,y$,:^p:j|,::*ev / Gather additionar pranning information vitar to thenstallation project

6' Allows multi-channel communications with isolated areas, especially whenntervening territo.ry.rimits.or prevents the use of repeaters,7 ' Desirable for multi-channel communications in iactical military field environmentor links from 30 to 2.00 mites iSO _ g+o k*l iong8. Thin-rine miritary svstems wiilriinr<s;i,i;';6ffiires (1480 km) rons.

Basic transmission lossPath loss variability.;-19 e_orotogical effects 1 effective distance / climate typesENERGY PER BIT) / (NOISE PER*HERTZ EANbWTD;HI. Deray dispersion / correration bandwioirr r murti_rever signaring

1' Select sites (radio, equipment plus tower locations) that are in Los of each othero maximize signalstrength.2' select an operational frefiuency band considering RF interference environment andegal restraints. "l

3' Develop path profiles to determine radio tower heights. If tower heights exceed aertain economic rimit, repeat step 1 to oiiig ihe sites croser together or. reconfiguring the path along the route.4' Perform path calculations, Aner setting a propagation reliability expressed as aercenrase f time, the RsL wiu be aboie tii.*,rr,olo i"r*rlFyi'ii#fr"**nt

threshold) of the FM receiver. set signal teveimirgin for fading under allanticipated climatic conditisns.

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2.3.

6.7.

8,9.

Establish a frequency plan and necessary operational parametersDetermine.equipment configurations to achieve the fade margins in mosteconomical manner / satisry technical.& legal *quir**ents. consider transmitteroutput, distance between siations, antenni size and height, Fresnel Zones, etc.M.ake necessary plans.l design and instalf equipmentAlign Antenna Beam, rine uilequipment, checriout equipment performance andsecure customer acceptance.



2.

3,

4,

1'9o19yct path oroflle chart using contour maps and profiting charts. use pathProfiling software if available.Conduct field inspection to determine ground suitability, antenna erection,equipment shelter buirding and amounl of clearinj required.use equipment such as; .z-way radios, binocularslru*"yort transit, radioaltimeters, DME, aneroid barometel, gtc. use compass or RDF for triangulation.conduct aerial reconnaissance and take aeriar pholographs if possibre, todetermine accessibiliry of.roads, power lines, and evade reflecting bodies of water,obstructions, navigational hazards, etc,Test signal strength / conduct propagation test.Determine wind-loading effects for tswer design,Conduct soil test for structural foundation design.

l+.lYE Of SIGHT (LOSI - no obstruction exists and antennas could ..seeo eachother,

EB$UN$-EAIS - the microwave beam just barely touches the obstruction qrthere is a zero clearance.OBSTRIf9TEP P+TH - the microwave beam is hindered by an obstruction.

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microwaves_handout1.pdf

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