weaverthorpe wind broadcast and point to point radio frequency links report

8/13/2019 Weaverthorpe Wind Broadcast and Point to Point Radio Frequency Links Report

1/19

Broadcast and Point to Point Radio Frequency LinksInterference report for Weaverthorpe Wind proposedturbine North of Cross Thorns Farm near WeaverthorpeNorth !orkshire

Prepared by Humberside CDA Limited

Jonathan Clarke BSc(hons) Enironmental Sciences

!thJuly "#$%

Tab"e of Contents&ntroduction'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''"he Proposal'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''Electroma*netic Communications Back*round''''''''''''''''''''''''''''''''''''''''''''''''''''''+

Curature o, the Earth''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''-.ear /ield &n,luence''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''-/resnel 0ones'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''1

Atmospheric 2e,raction''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''$#Atmospheric Absorption''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''$#

Point to Point 2/ Link Assessment'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''$"eleision 2eception &nter,erence Assessment''''''''''''''''''''''''''''''''''''''''''''''''''''$%Conclusion''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''"$3iti*ation'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''""2e,erences''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''""

I""ustration Inde#&llustration $4 he Electroma*netic Spectrum'''''''''''''''''''''''''''''''''''''''''''''''''''''''''5&llustration "4 he 2adio Spectrum'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''!&llustration %4 .ear and /ar /ields'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''-&llustration 4 /resnel 0ones''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''1&llustration +4 Lines o, Si*ht'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''1&llustration 54 Point to Point Links 6ith $##m Bu,,er'''''''''''''''''''''''''''''''''''''''''''''$"&llustration !4 7ind urbine 2adio /re8uency /or6ard and Back Scatter 0ones $&llustration -4 2/ Shado6s''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''$+&llustration 14 7eaerthorpe ransmitter Coera*e''''''''''''''''''''''''''''''''''''''''''''''$-&llustration $#4 Bilsdale ransmitter Coera*e''''''''''''''''''''''''''''''''''''''''''''''''''''''$1

&llustration $$4 7eaerthorpe 7ind urbine All Potential &nter,erence 0ones''''''"#&llustration $"4 7eaerthorpe 7ind urbine 2e,lection and Primary Shado60ones Closeup''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''"#

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2/19

Introduction

his assessment9 prepared by Humberside CDA Limited9 presents4

$' An assessment o, potential inter,erence 6ith point to point radio ,re8uency

(2/) links crossin* the area near the proposed 6ind turbine'"' An assessment o, potential inter,erence 6ith teleision reception in the

area near the turbine'

he operation o, 6ind turbines can inter,ere 6ith broadcast and othertelecommunications serices by causin* electroma*netic inter,erence (E3&)9 andthe possibility o, such inter,erence is a material plannin* consideration'

E3& can a,,ect communication systems in cludin* : reception9 mobile phonetransmitters9 micro6ae links$9 radar and aircra,t nai*ation beacons'

3icro6ae links can be a,,ected by re,lection9 scatterin*9 di,,raction and blockin*caused by 6ind turbines in their ;line o, si*ht,com (Bacon9 "##")'

7ind turbines hae the potential to cause inter,erence to teleision reception9primarily 6here a ie6er is in the ?shado6@ o, and 6ithin a ,e6 kilometres (km) o,a 6ind ,arm9 6ith their aerial pointin* to6ards the 6ind ,arm' :ie6ers in suchlocations can hae their si*nal ?scattered@ causin* loss o, picture detail9 loss o,colour or loss o, audio'

&t is also possible to su,,er inter,erence 6here si*nals re,lect o,, a 6ind turbine9

but this is *enerally ,ound to be less o, an issue than direct shado6in*'

his report does not consider the 6ider subect o, aiation impacts9 thou*h it is6orth notin* that &nter,erence 6ith air tra,,ic control ( AC) radars by 6indturbines has been obsered only 6ith lar*e turbines and in 6ind,arms utilityscale turbines -#m hi*h and up to $## turbines in a 6ind,arm' here are nopublished ha=ard reports or other published eidence o, small turbines a,,ectin*PS2s or AC operations'

he Companion uide to Plannin* Policy Statement "" (PPS"")4 2ene6ableEner*y discusses the plannin* and deelopment o, rene6able ener*y schemesacross En*land'

7ith respect to inter,erence 6ith electroma*netic transmissions9 the echnicalAnneF o, the Companion uide states that4 ;Specialist or*anisations responsible,or the operation o, the electroma*netic links typically re8uire a $##m clearanceeither side o, a line o, si*ht link ,rom the s6ept area o, turbine blades9 thou*hindiidual consultations 6ould be necessary to identi,y each or*anisation@s

$ A micro6ae link is a communications system that uses a beam o, radio 6aes in themicro6ae ,re8uency ran*e to transmit ideo9 audio9 or data bet6een t6o locations'

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3/19

sa,e*uardin* distance' E,,ects on such links can usually be resoled throu*hcare,ul sitin* o, indiidual turbines' and oFy*en9 >") is a maor,actor in radio propa*ation'

Heay rain and sno6 also a,,ect micro6ae reception9 an e,,ect 6hich is easilyobserable 6hen sno6 or heay rain disrupts satellite : reception'

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10/19

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11/19

Point to Point RF Link &ssessment

Pointy to point (PP) links are usually operate at a ,re8uency o, around $H= orhi*her (micro6ae ,re8uencies)' Pa*er Po6er Limited 6as commissioned toproide in,ormation on all static point to point links 6hich crossed throu*h the

area near to the turbine'

&llustration + sho6s the turbinesO oersailin* area as a yello6 circle andsurroundin* PP links as black lines 6ith $##m bu,,er areas around each link9marked in blue'

As can be seen ,rom the aboe illustration9 the only telecommunications link 6ithany proFimity to the proposed 6ind turbine crosses to the .orth 7est throu*hHelperthorpe and the turbine does not lie 6ithin the near,ield o, any 2/transmitters'

he PP link noted on the map is kno6n to be "km in len*th and the nearestend point is $#km ,rom Helperthorpe (the point o, closest approach to theturbine)' Assumin* a ,re8uency o, "'H= this yields a diameter ,or the second

/resnel =one o, %- meters at the closest approach to the turbine (calculatedusin* the ,resnel =one calculator at http4GGtomcle**'netG,resnel)

he proposed 6ind turbine is9 at its closest proFimity9 $'%km a6ay ,rom the linkand is thus 6ell outside the second ,resnel =one'

he Pa*er Po6er report did not identi,y the presence o, any : rebroadcast(2BL) links or super hi*h ,re8uency (SH/) links in the area' hese carry :si*nals bet6een transmitters'

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Illustration ": #oint to #oint Lin$s %ith 1&&m 'uffer


12/19

Te"evision Reception Interference &ssessment

eleision reception may be e,,ected adersely by 6ind turbines'

he ,orm o, inter,erence9 i, eFperienced9 6ill depend on the relatie positions o,

the 6ind ,arm9 the transmittin* station and the receier'&n practice the to6er or nacelle rarely has any e,,ect on : receptionN the impacton : reception is solely on account o, the rotatin* turbine blades' As the bladesare moin* obects9 in terms o, their rotation speed and orientation9 their e,,ect isariable and hard to predict'

he t6o mechanisms responsible ,or inter,erence are shado6in* e,,ects andre,lection e,,ects' he si=e o, the shado6 =one is dependent on the orientation o,the blades and is at a maFimum 6hen the aFis o, the rotor is in line 6ith thedirection o, the transmitted si*nal' he receied si*nal stren*th aries in a cyclicmanner9 in time 6ith the blade rotation' 2e,lection e,,ects ary 6ith the rotation o,

the blades9 the orientation o, the nacelle and the area o, the metallic componentsinside the blades'

he a,,ected area around the turbine is a combination o, the shado6 =one andthe re,lection =one and is rou*hly shaped like a keyhole' he actual shape andsi=e is dependent on the type o, turbine and the topo*raphy' /or the purposes o,assessin* the likelihood o, inter,erence9 the shado6 =one is considered to be asector 6ith a radius up to +km and the re,lection =one a circle o, radius o, +##m %'

he shado6 cast by a structure does not hae hard ed*es thou*h and does notusually eFtend inde,initely' 7hile there 6ould be a lar*e reduction in si*nal leelsimmediately behind the structure9 the blockin* e,,ect o, the structure diminishes

% >/C>39 "##19 all structures and their impact on broadcast and other 6ireless serices

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Illustration (: )ind Tur*ine Radio Fre+uenc, For%ard and 'ac$ Scatter!ones


13/19

6ith distance because o, di,,raction' Di,,raction is a process 6here si*nals appearto bend behind the structure and partially ,ill in the shado6'

&n *eneral9 there 6ill be three ?=ones@ behind the structure4

0one A close behind the structure (typically a ,e6 tens o, metres) there

may be a lar*e reduction in si*nal leel 6ith a possible complete loss o,reception'

0one B ,urther a6ay (typically a ,e6 hundred metres) the si*nalreduction is less seere and the shado6 6ill be smaller as di,,ractione,,ects partially ,ill in the shado6' Dependin* on the si=e o, the structure9some locations could still lose reception completely'

0one C some distance a6ay ($+km) the shado6 6ill e,,ectiely haedisappeared'

he resultin* shado6 is there,ore a trian*ular shape as sho6n in /i*ure "'

&t should be noted that the seerity o, the reduction and the actual si=e o, theshado6 6ill depend upon many ,actors includin* the construction o, the structureand its hei*ht the distances *ien aboe are ,or *uidance only'

&nter,erence to teleision caused by the operation o, 6ind turbines ischaracterised by de*radation to the ideo si*nal9 6hilst the audio component o,the si*nal is not a,,ected' eleision si*nals can be a,,ected by re,lection and,or6ard scatterin*'

2e,lection or back6ard scatter o, the si*nal results in the receier pickin* up aninter,erence si*nal as 6ell as the direct si*nal ,rom the transmitter' his type o,inter,erence is usually mani,ested by a ,luctuatin* ;*host< ima*e in analo*ue :systems' 2e,lection o, si*nals in di*ital : systems does not result in *hostin*

but may still cause errors in the di*ital si*nal'

/or6ard scatter occurs 6hen one or more 6ind turbines physically obstructs thepath o, the si*nal to the : receier' his can result in a de*radation o, the si*naland conse8uently ,luctuations in the intensity o, the picture' &n seere casesthere 6ill be insu,,icient si*nal stren*th to proide a picture'

Di*ital reception is inherently much more robust' >,com note4 ;2e,lections cansometimes cause reception problems' Di,,iculties are usually9 thou*h not

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Illustration -: RF Shado%s


14/19

eFclusiely9 eident on analo*ue 6ireless systems (di*ital systems are usuallymuch more resistant to the e,,ects o, re,lections)'SB%5 SE 1!"%!$55#9 approFimatly !## m to the .orth o, 7eaerthorpe' &t has a tip hei*ht o,$5m aboe sea leel'

&t broadcasts into t6o arcs (see illustration 1)' /or the purposes o, ourassessment 6e hae de,ined these as the .orth East and South 7est Lobes'

+ http4GGlicensin*'o,com'or*'ukGbinariesGspectrumG,iFedterrestriallinksG6ind,armsGtallstructures'pd,+ http4GG666'standard'co'ukGne6sGtechand*ad*etsGtheendo,analo*uetdi*itals6itchoeris

complete-""%1#'html5 http4GGlicensin*'o,com'or*'ukGbinariesGspectrumG,iFedterrestriallinksG6ind,armsGtallstructures'pd,

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http://www.bbc.co.uk/reception/info/windfarm_tool.shtmlhttp://www.ukfree.tv/http://www.bbc.co.uk/reception/info/windfarm_tool.shtmlhttp://www.ukfree.tv/


15/19

he South 7est Lobe coers an arc ,rom approFimately $-# de*rees to "-de*rees' he 7eaerthorpe 7ind urbines lies 6ithin this arc so could causeinter,erence to si*nals ,rom the 7eaerthorpe transmitter'

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Illustration .: )ea/erthorpe Transmitter 0o/erage


16/19

he Bilsdale transmitter is located at B2& 2&D >SB%5 SE ++$!+ 15%!9approFimately 1km ,rom 7eaerthorpe' &t has a tip hei*ht o, 5-$m aboe sealeel and broadcasts across most o, the .orth East o, En*land (see illustration 1)althou*h coera*e in the area around the reat 7olds :alley is patchy due toterrain e,,ects'

he 7eaerthorpe 7ind urbine could inter,ere 6ith si*nal reception ,rom theBilsdale transmitter'

Based on the >/C>3 *uidance9 a ;keyhole< inter,erence =one 6as then placedoer each turbine9 comprisin* a +##m circular re,lection =one centred on theproposed turbine and a +km lon* (the 6orst case scenario) $"# de*ree arc 6ithits point at the proposed turbine and central aFis ali*ned 6ith one transmitter9 thesecondary shado6 =one'

A third primary shado6 6as then added 6hich 6as a trian*ular area eFtendin*a6ay ,rom the transmitters ,rom the turbines oersailin* area ,or $km'

he three areas combine to represent an area 6here : inter,erence couldpotentially occur due to ,or6ard and backscatter ,rom the turbine'

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Illustration 1&: 'ilsdale Transmitter 0o/erage


17/19

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Illustration 11: )ea/erthorpe )ind Tur*ine ll #otential Interference !ones

Illustration 12: )ea/erthorpe )ind Tur*ine Reflection and #rimar, Shado%!ones 0loseup


18/19

Conc"usion

7e 6ould ud*e that households usin* satellite or cable : 6ill not e,,ected bythe proposed turbine'

here are no households usin* terrestrial analo*ue :'here is a ne*li*ible chance o, inter,erence ,or households usin* di*ital terrestrial: in the re,lection and secondary shado6 areas9 based on di*ital teleisionshi*h resilience to inter,erence'

here is a moderate chance o, inter,erence to di*ital terrestrial : receiers inthe primary shado6 =one'

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19/19

'iti%ation

&n respect o, micro6ae links9 *ien the turbine oersailin* area lies 6ell outsideo, the second ,resnel =one bu,,er ,or the nearby micro6ae link there is no risk o,inter,erence so no miti*ation is necessary'

&n respect o, teleision inter,erence9 6e 6ould recommend the ,ollo6in* courseo, action4

$' Kndertake a preconstruction terrestrial teleision surey o, Cross horns/arm'

"' &, the reception at Cross horns /arm is e,,ected by the turbine9 undertakeappropriate 6orks to sole the issue at the cost o, 7eaerthorpe 7indLimited'

%' /or a period o, t6o years ,ollo6in* construction9 inesti*ate any reports o,inter,erence 6ith teleision reception ,or residences 6ithin the re,lection

=one9 primary shado6 and secondary shado6 =ones and9 6here saidinter,erence is attributable to the 6ind turbine resole the issue'

he solution to any si*nal de*radation caused by the 6ind turbine 6ill inoleeither the redirection o, aerials or the supply o, an alternatie di*ital serice9 to beundertaken at the cost o, 7eaerthorpe 7ind Limited'

References

>,,ice ,or the Deputy Prime 3inister9 "##9 Plannin* ,or 2ene6able ener*y4 ACompanion uide to PPS""9 H3S>9 K>/C>39 "##"9 /iFedlink 6indturbine eFclusion =one method' Author4 D /

BaconS :ila3oreno9 A 3ethodolo*y to Assess &nter,erence to : 2eception due to7ind /arms9 2ES9 "##+&nternational elecommunications Knion9 $11"&K2 B'-#+9 recommendation;Assessment o, impairment caused to teleision reception by a 6ind turbine/C>39 "##19 all structures and their impact on broadcast and other 6irelesssericesJ2C9 "##19 Calculation o, 7ind urbine clearance =ones ,or J2C KH/ (5#3H=)elemetry Systems 6hen turbine si=es and locations are accurately kno6nConnell 7a*ner len &nnes 7ind /arm Enironmental Assessment elecommunications inter,erence >ctober "##-

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weaverthorpe wind broadcast and point to point radio frequency links report

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