Welcome To The Antenna Summit Sponsored By NADXA Northern Arizona DX .

Welcome to the Antenna SummitSponsored by NADXANorthern Arizona DX Association1

Thank YouNAU – Cline Library2

Session 6 – ARRL Antenna BookChapter 1 - Antenna Fundamentals3

Instructor Ron GerlakKG7OH – Amateur Extra ClassLicensed 1977ARRL ANTENNA BOOK 24th Edition 2019Q & A at the end of each chapterVia ChatEmail questions to: KG7OH@arrl.net - Anytime4

Radio SystemRadio PuzzleTransmitter, Receiver and Antenna SystemGet a Signal from Your Transmitter toThe other hams AntennaPropose of AntennasRadiate and receive electrometricwavesReciprocityAlways& Never5

Dissipated Electromagnetic WavesDissipated Electromagnetic WavesRadiation of Electrometric WavesRadiated as Heat Antennas close to groundAntennas made of very small wireReducing Losses Increased Radiation Efficiency6

ANTENNASElectromagnetic WavesE Electrical FieldDetermines PolarizationH Magnetic Field7

ANTENNASArray of Light (Next Generation of Antennas)Tom Schiller, N6BTAnything Works (Tom Schiller, N6BT)Everything matters8

What MattersVSWRNear & Far FieldsDirectivityImpedanceType of GroundTake-Off AngleHeight Above GroundGainFree Space9

Impedance Feed Point Impediance– Self and Mutual Impedance– Feed Point Impedance is Low where the voltage is low At the center of a dipole ResonanceAn antenna can be resonant only at one frequencyCurrent and voltage are in phase10

FieldsNear FieldFar FieldBoundary D 2L2/Wavelength(Within 2 Wavelengths of the Feed Point)11

DIPOLE ANTENNA12

E and H Wave Forms13

Antenna Voltage and CurrentDistribution14

15

DecibelsMeasures intensity of sound and powerLog scaleJust add them up or subtract themPower x 2 3dB 3dB Gain 6dB 1 S-unit HigherSo Double the power twice 1 S-unit16

Power – dB – S Units From 100 watts to 200 watts 3dB. From 200 watts to 400 watts 3dB. 3dB 3dB 6 dB 1 S-unitS617

Power – dB – S Units From 100 watts to 200 watts 3dB. From 200 watts to 400 watts 3dB. 3dB 3dB 6 dB 1 S-unitS718

- or Change from a Dipole to a 3 element Yagi 6 dBd 1 S-unitSame transmit result doubling doubling powerConsiderable improvement in receivingS619

- or Change from a Dipole to a 3 element Yagi 6 dBd 1 S-unitSame transmit result doubling doubling power1 S-unit improvement in receivingS720

Fields and Waves RF Waves change with time (Electromagnetic)E FieldsElectric Wave90 Degrees to the H FieldIncreases with VoltageMost Relevant to Ham RadioDescribes the Polarization of an AntennaH FieldsMagnetic WaveIncreases with Current21

TYPES of PATTERNS 3D Pattern Azimuthal Pattern Elevation Pattern22

ISOTROPIC ANTENNA23

3D ISOTROPIC ANTENNA PATTERN24

ISOTROPIC ANTENNA PATTERN SLICEElevation PatternAzimuthal Pattern25

Horizontal DipoleThe dipole is the simplest type of real antennafrom a theoretical point of view. Mostcommonly it consists of two conductors of equallength oriented end-to-end with the feed-lineconnected between them.26

3D DIPOLE ANTENNA PATTERN27

3D DIPOLE PATTERN SLICE28

DIPOLE PATTERNHorizontal PatternAzimuth PatternVertical PatternElevation Pattern29

Horizontal Dipole PatternAzimuth PatternIsotropic shown in Red3D Pattern30

Gain Dipole has 2.15 dBi gain over an Isotropic Antenna Signal from the ends is redistributed to the broadside31

GainAntennas are passive devices and do notgenerate any “extra” power.Where does the gain come from?Gain is achieved by redistribution of pattern32

DB Referance Isotropic antenna as the referenceDipole has 2.15 dBi GainYagi has 6 dBd GainDipole antenna as the referenceYagi has 8.15 dBi Gain(Same antenna)Isotropic antenna as the reference33

Tri-Band Yagi 10 – 15 - 2034

YAGI (Gain Antenna) PATTERN(Azimuth)35

Azimuth ½ Power Points of a YagiBeam Width0 dB30 Degrees0-3-6-92703 dB Down½ Power Point9018036

Q - Quality Narrower Beam width Higher Q Higher the Gain Higher QMore GainMore DirectivityMore Selectivity37

Q - Quality38

Q - QualityBeam Width of AntennasTransistorsResonant RLC Circuits39

Azimuth ½ Power Points of a YagiHigh “Q”Beam Width0 dB20 Degrees0-3-6-92703 dB Down½ Power Point9018040

Elevation Pattern of a Yagi00 dB-3-6-92709018041

Polarization HorizontalVerticalCircularSky-waves42

Scaling ScalingLength, Spacing, Boom & Element Diameter43

ERP & EIRP (EiRP)Effective Radiated Power TPO 100 watts 50 dBmTransmission line attenuation 2.4 dBLosses in RF connectors and coupling 1.7dBAntenna gain 7.5 dBiEIRP 50 dBm – 2.4 dB – 1.7 dB 7.5 dB 53.4 dBm 219 watts44

Safety Thermal EffectsAthermal EffectsRadiationPower DensitySafe LevelsPacemakers45

Thermal Effects of RFMicrowave cooks using RF EnergyBody’s Natural Resonant Frequency35 MHz – Grounded70 MHz - Insulated from groundSAR – Specific Absorption RateMPE – Maximum Permissible Exposure46

Athermal Effects of EMRElectromagnetic RadiationElectromagnetic FieldEnergy Fields – At Home/Work– Electric Drill, 500 – 2000 milligauss– Hair Dryer, 200 – 2000 milligauss– Electric Blanket, 30 – 90 milligauss– HF Transceiver , 10 – 100 milligaussSome studies – Weak associationEMF & Malignant ConditionsMore studies – No association47

RadiationIonizing – Always a danger– X Rays– Gamma Rays– Nuclear PowerNon-Ionizing – Sometimes a ConcernRF Field60 Hz Field48

Power DensityScientific community disagree on guidelinesMeasurement equipment is expensiveARRL RF Awareness GuidelinesPage 1.24, Table 1.349

ARRL RF Awareness Guidelines Keep people away from antennasKeep mobile power to 25 wattsMake antenna heights 35’Keep equipment covers installedDon’t point directional antennas toward peopleUse a speaker microphones with HT radiosKeep a distance from transformers & fans50

Safe Exposure LevelsSTATIONS MUST BE EVALUATED Controlled EnvironmentsUncontrolled EnvironmentsE FieldH FieldDifferent FrequenciesTime Period AveragingExperts Do Not Agree51

Safe Exposure LevelsNO EVALUATIONS REQUIRED 100 maximum watts okay an all Bands except: 50 watts or less on:12 Meters10 MetersVHFUHF(Table B, Page 1.21)52

Pacemakers DISCUSS THIS WITH YOUR PHYSICIAN!53

Session 6 – ARRL Antenna BookChapter 2 - Dipoles and Monopoles54

Dipoles and Monopoles Effects of Conductor DiameterRadiation Patterns and Effects of GroundFeed Point ImpedanceEffects of Frequency on Radiation PatternFolded DipolesVertical DipolesOff Center Fed (OCF) DipolesMonopolesFolded Monopoles55

DIPOLES Fundamental Antenna56

Dipole Length Calculationsλ/2 Dipole Resonant Length (in free space)491.786 / f(in MHz) Length in FeetExample of 40 Meter Dipole:491.786 / 7.2 68.29’57

Dipole - K FactorLength Correction for DiameterDipole Length Corrected for Diameter of #12 AWG(.969 - .976) Page 2.2, Figure 2.3491.786 / 7.2 68.29’.97 x 491.786 / 7.2 66.3 Feet58

Dipole - Velocity FactorDipole Length Corrected for Insulated WireReference Material says about .95%My experience says about .99%491.786 / 7.2 68.29’.97 x 491.786 / 7.2 66.25’.99 x .97 x 491.786 / 7.2 65.60’59

Dipole – Type of Ground Very Poor Soil Ground Good Ground Salt Water60

Dipole – Height FactorResonant length changes up and down as theheight above ground changes.61

Dipole LengthUSE THIS FORMULA IN THE FIELD The book says 468 / f for λ/2 Soooo 234 / f(MHz) the λ/4 element Length Cut it 2 feet longer and wrap it back on itself.Element length 234 / fthen add 2’ just in case 234 / 7.2 32.5 Then add 2 34.562

DIPOLES Fundamental AntennaMake these the actualcalculated lengthWrap extra wire hereWrap extra wire here63

Dipole Length Check SWR dip with Antenna Analyzer Adjust as needed:Lengthen Antenna Lowers Dip Frequency64

Dipole LengthTo lower the dip makethe antenna longer65

Dipole LengthNeeds to be more longer66

Dipole LengthJust the right length67

Dipoles Height Above Ground68

DIPOLES Fundamental Antenna69

Folded Dipole70

Monopole / Vertical71

Vertical Dipole72

OCF Dipole73

Antenna Voltage and CurrentDistribution74

Feed Point ImpedanceDipole feed point impedance 72 ΩInverted V feed point impedance 50 ΩFolded Dipole feed point impedance 280 ΩOCF Dipole feed point impedance 150 - 300 ΩSlopped feed point impedance 80 ΩVertical Monopole feed point impedance 36 Ω75

Antenna Modeling EZNECwww.eznec.com76

Next Session –ARRL ANTENNA BOOKChapter 3The Effects of Ground77

Session 6 -ARRL Antenna Book Chapter 1 - Antenna Fundamentals 3. Instructor Ron Gerlak KG7OH -Amateur Extra Class Licensed 1977 ARRL ANTENNA BOOK 24th Edition 2019 Q & A at the end of each chapter Via Chat Email questions to: KG7OH@arrl.net - Anytime 4. Radio System 5