A Five Element Parasitic Rotatable Vertical Yagi for

160 meters JoelHarrison,W5ZN

2018DaytonHamventionAntennaForum

The Need for a New TX Array •  10yearsperfectingRXarraysatW5ZN

•  260DXCCcountriesconfirmedbutbecamestagnate•  Thecountriesneededaremuchmoredifficulttowork

• NeededextraTXgainanddirectivitytoadvancemyDXstandingsfromArkansas

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The Search for the Right Array at W5ZN •  Spentwellovertwoyearsfrettingoverwhattodo• Revisitedthesectiononverticalarrayswithparasiticelementsin“LowBandDX’ing”•  Chapter13,Section3.9,page13-39FifthEdition

•  Studiedthedesignforabout2weeks•  Literallybecameobsessedwiththisdesign

• K3LR’sversionisdescribed•  TraveledtoK3LRtoseehisinstallation•  FurtherdiscussionwithK3LRatSixMeterBBQinAustininSept2017

• BecameconvincedthiswastheperfectarrayfortheW5ZNstationW5ZN

Why a Vertical Yagi Array with Parasitic Elements Over a 4 Square? •  ThearraycanbebuiltaroundanexistingsingleTXvertical

• Donotneedfullsizeelements

•  ExistinglandareaaroundthesingleTXverticalcanbeutilized

•  SamebasicgainandF/Bisrealizedin4rotatabledirection

• Verysimplefeedsystem.Nophasingorcomplicatedschemes.Theexistingmatchingnetworkonmysingleverticalisallthatisrequired

•  Slightlysmallerelementfootprintthan4Square

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HorizontalPatterat20degreeselevation

25dBF/B5dBForwardGain

EquivalentForwardGainandF/B

Why a Vertical Yagi Array with Parasitic Elements Over a 4 Square?

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The Vertical Yagi Array with Parasitic Elements • PopularizedbyBillHohnstein,K0HA

• Comprisedof3ormoreverticalelementswithoneactivedrivenelementandtherestparasitic

• CurrentlyinuseatAA1K,VE3EJ,K3LR,NR5M&K9CT•  AA1Khasa2ndDirectortoEuropeonhisarrayforatadmoregain

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•  Toploadedverticalparasiticelementsareextremelyeffective

•  ElementscanbeeasilysuspendedwithcatenaryropesfromtheexistingTXvertical

The Top Loaded Vertical Element

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The Top Loaded Vertical Element • Resonantwithashorterverticallength

• NoFarFieldhorizontalcomponentasthetoploadwireissymmetricaltoverticalwire.

•  Slopingtoploadingwireis~65ft.

• Verticalwireis~75ft.

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Constructing the Array • Constructioneffortorganizedinto5Phases

1.  PhysicalLayout2.  RadialSystem

3.  ElementConstruction&Erection

4.  Tuning5.  ParasiticArraySwitching

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Physical Layout • VerysimpleProcess–30minsorless

•  Elementsspaced66ft.fromDrivenElement

•  4parasiticelementsspaced90degreesaroundadrivenelement

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Radial System •  Themostcomplicatedandtimeconsumingpartoftheproject•  ItisMOSTimportant!!!!

• Parasiticarrayshaveagreaterimpactfromapoorgroundsystem

•  Elevatedradialssimplywon’twork•  ON4UN’smodelingshowssignificantpatterndistortion

• Withaphasedarray(e.g.4Square)currentdistributionisforcedintoeachelement

• Propercurrentdistributionandthusgaininaparasiticelementisimpactedbygroundresistancesoaneffectiveradialsystemismandatory

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Radial System • Gainof3elementarrayasafunctionofgroundlossresistance

• CaseAisforadrivenelementwithafixed1Ωlossresistancebutwithvaryinggroundlossresistanceattheparasiticelements

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Radial System •  120radialsusedundereachelement

• Radialsaretiedtogetheratintersectingpoints

•  13.7miles(22KM)ofwireusedinradialsystem

0.18λ

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• W5ZNconstructionprocedure1.  Install120radialsfromdriven

elementto48ft.perimeterwire

2.  Installradialsfromeachelementthatintersect48ft.diameterperimeterwire

3.  Installallradialsfromeachelementthatintersectthecrossbusswire

4.  Installallremaining1/4λlengthradialstocompleteatotalof120ateachelement

Radial System

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Radial System •  48ft.diameterperimeterwire(#4solidcopper)arounddrivenelement

•  120radialsfromthedrivenelementtiedtothisperimeterwire

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Radial System • Perimeterwirelaidina48ft.diametercirclearounddrivenelement

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Radial System • Radialwiresfromthedrivenelementaresolderedtotheperimeterwire

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Radial System • Radialwiresfromeachelementthatintersecttheperimetercirclearesolderedtotheperimeterwire.

• Allconnectionsarethencoatedwithliquidtape

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Radial System •  Someoftheradialwiresfromanelement.

•  IdoNOTburyradialwires!

• Mowgrassveryshort(don’tscalp)andlayradialsontheground.Securewithradialstaples

• Newgrassgrowthinspringwillcoverthewires.

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Radial System •  Youcanuseanysoundmethodforattachingradialswiresattheelements.IprefertheDXEngineeringRadialPlates

•  Icrimp&soldertheradialwirestoringterminallugsthencoatthejointwithliquidtape.

•  IusePenetroxtomaintainagoodconnectionovertimeandpreventgalvaniccorrosionwithdifferentmetalsoftheplateandterminals

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Radial System • Completedradialsystemunderoneelement

•  Iusebiodegradablestaplestoholdradialsinplacepriortonewgrassgrowth

•  Totalradialsystemarea<2acres

•  Totalconstructiontimeforradialfield-4weeks

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Element Construction •  Eachelementwillneedtofunctionasadirectorandareflectorfordifferentdirections

•  Toaccomplishthis,theelementisswitcheddirectlytotheradialsystemasadirector,orthrougha4uHinductortofunctionasareflector

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Element Construction & Erection • Vertical&toploadexactlengthsareachievedbytrial&error

• Buildoneelement,erectitandthentunetothetargetfrequency.Theremainingelementsshouldbethesame.

• Usearopeandpulleyonthefirstelementunlessyouenjoyclimbing135ftmultipletimes!!!!

• Distancefromdrivenelementtofirstinsulatoronthetoploadingsegmentwillbeapprox.45ft.

• Distancefromdrivenelementtoendtiepointwillbeapprox.265ft.

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Element Construction

ON4UNModel

K3LRSystem

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TopLoad 64.7ft. 58.3ft. 58.3ft. 65ft.Vertical 75.5ft. 64.2ft. 64.2ft. 75ft.Director 1935KHz 1904KHz 2070KHz 1904KHzReflector 1778KHz 1800KHz 1950KHz 1800KHz

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Tuning - Each Element • Connectanantennaanalyzerbetweentheverticalelementandtheradialsystem

•  Switchintheverticalwiredirectlytotheradialsandadjustthelengthtothedesireddirectorfrequency

•  Switchintheverticalwireandinductortotheradialsandadjusttheturnsspacingontheinductorforthedesiredreflectorfrequency

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•  Thesystemhasan“Omni”modewhenallfourparasiticelementsarefloatinghoweverthereisadifferenceinfeedpointimpedancecharacteristicswhenthearrayisactive.•  TheOmnimodesprimarypurposeisRXsignalcomparison

• MakefinalSWRtuningadjustmentswiththe“array”active

•  Shouldrealizeaverylow1.1:1SWRwitha1.5:1bandwidthofapproximately40KHz

Tuning – As an Array

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Tuning – As an Array

40KHzBandwidthFinalAdjustmentProduceda1.1:1SWRat1.825MHzW5ZN

Tuning – Fine Tweaking • Driveoutapproximately1to2milesineachofthefourdirectionswithalowlevelsignalsource

• AdjustformaximumF/B–Procedure:1.  Drivetotheoppositedirection,e.g.SWfortheNEdirection2.  SelecttheNEDirectionforthearray3.  Transmitfromthedistantlowlevelsignalsource4.  Adjusttheturnsspacingonthereflectorelementinductorforlowestsignal

(maxF/B)

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Array Switching

• GregOrdy,W8WWVdesignedacircuitboardforK3LR

• Onceassembleditcontainstworelaysandinductor

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Array Switching • A5positionswitchboxisusedtoswitcharraydirection

•  Foronedirection,relay1isenergizedontheforwarddirectorelementandrelay2ontherearreflectorelement

• Unusedelementsarenotconnectedfromtheirradialsand“float”

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Array Switching •  Switchboardinstalledatoneelement

• Plasticboxhousingusedateachparasiticelement

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Array Switching

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What the Heck is That Roll of Cable? •  160meter1/4λshortedstub

•  The160arrayisclosetoW5ZN’s80meter4Squarearray

•  Invisibleon160meters•  Stubisinvisibleon160meters,appearsasan“open”

• On80metersthisis1/2λandappearsasa“short”atthefeedpoint

•  Eliminates/minimizesinteractionbetweenthetwoarrays

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•  TheSoutheast160meterelementisonly60ft.fromthenortheast80meter4Squareelement

What the Heck is That Roll of Cable?

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On-the-Air Results • Realize5dBforwardgain•  F/B~25dB• RBNindicatessignificantimprovementoversinglevertical

•  Significantimprovementinpileups!

•  9MØWSpratly160meteroperatorJeff,K1ZM:“YoursignalwasbetterthanMOST!AboutRST339whichmaynotsoundLOUD-butcomparedtoalltheothersatRST219,youwereLOUD(HIHI)”

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Acknowledgements •  TimDuffy,K3LR

•  JonZaimes,AA1K

•  LarryBurke,K5RK

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