AIM4170 ANTENNA ANALYZER Part 1

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2 PART 1 INTRODUCING THE ANALYZER Antenna impedance what does it mean? AIM4170 capabilities Examples PART 2 USING THE ANALYZER AS A DESIGN TOOL Designing a 160m/80m Trap Dipole Measuring the Antenna Feedpoint Impedance Remote AIM4170 Operation 2

3 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 3

4 Live Demonstrations Tuning a 70MHz groundplane Measuring discrete components (L, C) Tuning traps Designing a 160m/80m trap dipole Determining antenna feedpoint impedance Conjugate matching in the ATU Remote control of the AIM4170 via a WiFi link 4

5 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 5

6 AIM4170 Network Analyzer from Array Solutions Vector Mode Single-port Vector Network Analyzer (VNA) measures impedance Time Domain Reflectometry (TDR) Mode measures time/distance 6

7 AIM4170 Vector Mode Frequency Coverage: AIM4170B: 100kHz-180MHz AIM4170C: 5kHz-180MHz Resistance and reactance: at the feeder input at the antenna feedpoint Resistance, reactance and Q of discrete components Return loss, reflection coefficient, SWR Cable length, cable impedance, cable loss Distance to fault (open or short), stub tuning Smith chart display Band scan for interfering signals Quartz crystal parameters Synthesized frequency source for receiver / filter testing Software controlled No internal calibration adjustments 7

8 AIM4170 Connection to the Antenna AIM PC AIM4170 8

9 AIM4170 Connection to the PC AIM PC running AIM software RS232 Serial Link to antenna under test 9

10 AIM4170 Front Panel 10

11 AIM4170 Rear Panel 11

12 AIM4170 Internal Construction 12

13 AIM4170 Input Protection Series relay only closed when scanning Gas discharge tube connected directly to ground 100K resistor connected directly to ground Back-to-back silicon diodes in the measurement circuit The input to the AIM is DC coupled, so be sure there is no DC control voltage present on the line 13

14 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 14

15 Feedpoints Antenna Feedpoint Feeder TX Feeder Feedpoint ATU 15

16 Antenna System ANTENNA SYSTEM Antenna Feedpoint TX Antenna System Matching Unit Feeder Feedpoint Feeder ATU 16

17 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 17

18 Impedance (Z) and Reactance (X) of the Antenna System Impedance (ohms) = Resistance (ohms) + j Reactance (ohms) Z = R + j X R Radiation Resistance DC Resistance + j X AC Resistance due to Inductance/Capacitance 18

19 Vectors and j Impedance (ohms) = Resistance (ohms) + j Reactance (ohms) Z = R + j X = 30 + j 62 Reactance (X) + 62 ohms j means rotate the vector by 90 o Resistance (R) 30 ohms 19

20 Inductive and Capacitive Reactance Resistance (R) 30 ohms Inductive Reactance (X) + 62 ohms Capacitive Reactance (X) 62 ohms Resistance (R) 30 ohms Z = 30 + j 62 Z = 30 j 62 20

21 Inductive and Capacitive Reactance (X) L X L (ohms) X L = 2 f L L = 1 µh 1 10 f (MHz) C f (MHz) X C = 1 2 f C C = 1 nf X c (ohms) 21

22 Vectors and Phase Angle (theta) At 10MHz X L = µh R = o V I +64 o Z = 30 + j Zmag = X C = nf R = o Z = 30 j Zmag = V I -28 o 22

23 Non-Resonant Antenna (at 5MHz) X L (ohms) f (MHz) L = 1 µh C = 1 nf 5 f (MHz) X c (ohms) At 5MHz X L = X C = µh 1 nf R = o V I Z = 30 + j j = 30 j o 23

24 Resonant Antenna At resonance, the inductive reactance and the capacitive reactance are equal in magnitude and opposite in sign. X L = X C 2 f L = f res = f f C 1 2 (L C) 1 f res = = 5.033MHz 2 (1 µh * 1 nf) 24

25 Resonant Antenna (at 5.033MHz) X L (ohms) f (MHz) L = 1 µh C = 1 nf f (MHz) X c (ohms) At 5.033MHz X L = X C = µh 1 nf R = V I Z = 30 + j j = 30 + j 0 0 o 25

26 AIM4170 Computations 1. Accurately measures the voltage, current and phase angle (theta) V I Vmax +57 o Vmin 2. Computes the resistance & reactance vectors, and the impedance Z = V / I Z = 30 + j Zmag = o Computes the SWR, reflection coefficient, cable loss etc SWR = Vmax Vmin 26

27 AIM4170 Block Diagram 5kHz 180MHz 27

28 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 28

29 Impedance at the TX, Feeder and Antenna The feeder is really an impedance transformer TX Feeder ATU Z T = R T + jx T = 50 + j0 Z F = R F + jx F = 30 - j22 Z A = R A + jx A = 16 + j123 29

30 AIM4170 Measurement Points ANTENNA SYSTEM AIM4170 Feeder Z F = R F + jx F = 30 - j22 Z A = R A + jx A = 16 + j123 30

31 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 31

32 AIM4170 Functions

33 AIM4170 Functions

34 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 34

35 AIM4170 Component Measurement 35

36 Measuring Capacitance 36

37 Measuring Inductance 37

38 Tuned Circuit Resonance 38

39 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 39

40 20m Dipole (Courtesy Bob, W5BIG) 40

41 G5RV 1-31MHz 41

42 G5RV on Top Band coax feed 42

43 G5RV on Top Band strapped feed (Marconi T) 43

44 160m Inverted L at 140 feet (Courtesy Paul, VE7BZ) 44

45 Hustler 5-BTV: 15m (Courtesy Andy, M5ALA) 45

46 Hustler 5-BTV: 20m (Courtesy Andy, M5ALA) 46

47 Hustler 5-BTV: 40m (Courtesy Andy, M5ALA) 47

48 Hustler 5-BTV: 80m (Courtesy Andy, M5ALA) 48

49 Antenna Loading (Courtesy Steve, VK2ZSZ) 49

50 2kW Dummy Load 1-151MHz 50

51 2kW Dummy Load 1-151MHz 51

52 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 52

53 Crystal Parameters 53

54 Short Circuit 54

55 Distance to Fault (short circuit) 55

56 Tuning a Quarter-Wave Stub 56

57 Band Scan 57

58 Frequency Markers 58

59 Marker Data 59

60 Spreadsheet 60

61 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 61

62 Smith Chart 62

63 50-ohm Termination: 1.5m Feeder 63

64 Smith Chart: Cable Attenuation 1.5m Feeder 80MHz 40MHz 70MHz 0.68 j0.53 x = 53 j41 64

65 50-ohm Termination: 32.5m Feeder 65

66 Smith Chart: Cable Attenuation 32.5m Feeder 66

67 AIM4170 PART 1 1: Introduction to the AIM4170 2: Some Basic Definitions 3: Impedance, Resistance and Reactance 4: Impedance at the Transmitter, Feeder and Antenna 5: AIM4170 Functions 6: Measuring Capacitance, Inductance and Resonance 7: Typical Antenna Scans 8: Some other AIM4170 Functions 9: The Smith Chart 10: Time Division Reflectometry (TDR) Mode 67

68 Basic TDR 68

69 TDR Menu 69

70 75-ohm feeder in series with 50-ohm feeder Antenna 75-ohm Feeder 50-ohm Feeder 70

71 Feeder with Low-Pass Filter inserted Antenna without LPF with LPF Feeder 50 MHz Low-Pass Filter 71

72 AIM4170 ANTENNA ANALYZER End of Part 1 28 April

73 AIM4170 ANTENNA ANALYZER Ian Wade, This presentation is located at: homepage.ntlworld.com/wadei/aim4170.htm 73

75 PART 1 INTRODUCING THE ANALYZER Antenna impedance what does it mean? AIM4170 capabilities Examples PART 2 USING THE ANALYZER AS A DESIGN TOOL Designing a 160m/80m Trap Dipole Measuring the Antenna Feedpoint Impedance Remote AIM4170 Operation 75

76 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 76

77 Live Demonstrations - 2 Designing a 160m/80m trap dipole Determining antenna feedpoint impedance Conjugate matching in the ATU Remote control of the AIM4170 via a WiFi link 77

78 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 78

79 Designing a 160m/80m Trap Dipole At 80m λ / 2 at 80m 80mTrap B Balun At 160m λ / 2 at 160m A C Loading Coil B Balun 79

80 80m Trap 80

81 80m Trap: Resonant Freq = MHz 81

82 The Dipole at 80m At 80m λ / 2 at 80m MHz B Balun From the Antenna Handbook: B = λ / 4 at 3.69MHz = 67 ft 6 inches (20.574m) 82

83 80m Trap at 1.86MHz: Inductance = 9.18µH 83

84 The Dipole at 160m At 160m λ / 2 at 1.86MHz A 9.18 µh 67 6 Balun 84

85 Calculating the Required Wire Lengths µh 67 6 (Courtesy Martin, K7MEM) 85

86 Calculating the Required Wire Lengths µh 67 6 (Courtesy Martin, K7MEM) 86

87 The Finished 160m/80m Trap Dipole Design m trap m trap Balun 87

88 Actual 160m/80m Dipole Results 88

89 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 89

90 Antenna System with Basic Feeder ANTENNA SYSTEM Feeder TX ATU 90

91 No resonance on 20m 91

92 Antenna System with Extra 1.5m of Feeder Original Feeder TX Extra 1.5m of Feeder ATU 92

93 Extra 1.5m feeder: resonance on 20m 93

94 No resonance on 20m 94

95 Antenna System with Extra 3m of Feeder Original Feeder TX Extra 3m of Feeder ATU 95

96 Extra 3m feeder: resonance (almost) on 30m 96

97 Extra 1.5m feeder: resonance on 20m 97

98 Original Feeder 98

99 The feeder is really an impedance transformer AIM4170 Feeder Z F = 30 - j22 Z A = 16 + j123 99

100 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 100

101 One Way to Read the Antenna Feedpoint Impedance AIM

102 Custom Scan The AIM4170 reverses out the feeder impedance transformation to obtain the antenna feedpoint impedance AIM4170 Feeder Z A = 16 + j123 Z F = 30 - j22 Z A = 16 + j

103 Custom Feeder Calibration AIM4170 Feeder 1. Short Circuit 2. Open Circuit 3. Known Resistance The custom calibration process is frequency dependent, so it is necessary to produce a custom calibration file for each band. 103

104 Example: 50-ohm Resistive Load AIM4170 Feeder 50 ohms Z A = 50 + j0 Z F = 62+ j1 Z A = 50 + j0 104

105 50-ohm Resistive Load: without correction Z F = 62 + j 1 105

106 50-ohm Resistive Load: with custom correction Z A = j

107 70MHz Groundplane: at feeder feedpoint Z A = 43 + j 0 107

108 70MHz Groundplane: at antenna feedpoint Z A = 31 - j

109 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 109

110 Conjugate Matching The ATU has to convert the feeder feedpoint impedance to 50 + j0 TX Feeder ATU Z T = 50 + j0 Z F = 30 - j22 110

111 ATU Matching (Courtesy Mike, WY2U) 111

112 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 112

113 AIM4170 Remote Control AIM PC AIM

114 AIM4170 Remote Control AIM PC WiFi Connection Remote Netbook AIM

115 Remote Desktop Control Server and Client AIM PC running AIM software and RealVNC remote desktop control software Wireless Router WiFi Remote netbook running Java-enabled web browser (any operating system) to antenna under test 115

116 Hazards of Remote AIM Control Difficult to view display in bright light (need to increase screen brightness, increasing battery drain) Risk of dropping the netbook (wear it on a halter around the neck) Risk of overflying birds.. (tape some cling film over the keyboard, or dress like a scarecrow and wave your arms about) 116

117 Remote Operation through Wireless RS-232 Link WiFi RS-232 Link VSC-X to antenna under test 117

118 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 118

119 Analyzer Comparisons - 1 AIM4170 (Courtesy Bob, W5BIG) 119

120 Analyzer Comparisons - 2 AIM4170 UK (Oct 2010)

121 AIM4170 PART 2 11: Designing a 160m/80m Trap Dipole 12: The Feeder as an Impedance Transformer 13: Measuring the Antenna Feedpoint Impedance 14: Conjugate Matching 15: Remote AIM4170 Operation 16: Analyzer Comparisons 17: Conclusions 121

122 Conclusions The AIM4170: Accurate Software controlled Updateable Easy to use Remotely controllable Detailed scan documentation 122

123 UK Supplier Vine Antennas Ltd 123

124 Some Related Links AIM Software and Documentation: Comparisons between AIM4170 and other analyzers: Product Reviews, QST, August 2007 AIM Discussion Forum: aim4150.proboards.com/index.cgi RealVNC Remote Desktop Server: Interactive Tutorials on Transmission Lines, SWR, Smith Chart: Owen Duffy s Experimenter s Notebook: vk1od.net 124

125 RadCom Review July

126 Some Related Books The ARRL Antenna Book: Reflections III: by Walter Maxwell, W2DU w2du.com Antenna Topics: by Pat Hawker, G3VA 126

127 Acknowledgements Many thanks to the following who kindly gave permission for their work to be included in this presentation: AIM Software and Product Information, by Bob, W5BIG 160m Inverted L Plot, by Paul, VE7BZ (ve7bz@shaw.ca) Hustler Antenna Plots, by Andy, M5ALA (andrew@amsnorthwest.co.uk) Electrically Short Halfwave Dipole, by Martin, K7MEM (martin.e.meserve@lmco.com) L/C Impedance Matching Network Design Tool, by Mike, WY2U (wy2u@optonline.net) Analyzer Comparisons, by Bob, W5BIG (bob@w5big.com) 127

128 FINAL FINAL W A R N I N G The AIM4170 is H U G E LY addictive! 128

129 AIM4170 ANTENNA ANALYZER Ian Wade, This presentation is located at: homepage.ntlworld.com/wadei/aim4170.htm 129

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