AIM4170 ANTENNA ANALYZER Part 1 Ian Wade, G3NRW g3nrw-radio@ntlworld.com 8 September 2011 Copyright © 2010,2011 Ian Wade All Rights Reserved

AIM4170 Antenna Analyzer 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

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

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

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

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

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

AIM4170 Connection to the Antenna PC AIM4170 AIM

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

AIM4170 Front Panel

AIM4170 Rear Panel

AIM4170 Internal Construction

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

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

Feedpoints Antenna Feedpoint Feeder Feeder Feedpoint TX ATU

Antenna System Antenna Feedpoint Antenna System Matching Feeder Unit TX ATU

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

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 X “AC Resistance” due to Inductance/Capacitance + j

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

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

Inductive and Capacitive Reactance (X) XL (ohms) L + 62.84 XL = 2  f L L = 1 µH + 6.284 f (MHz) 1 10 1 10 C f (MHz) – 15.91 – 1 2  f C XC = – 159.1 C = 1 nF Xc (ohms)

Vectors and Phase Angle (theta) At 10MHz 30 + 62.84 + 64 o 69.93 V I +64 o XL = + 62.84 1 µH R = 30 Z = 30 + j 62.84 Zmag = 69.63 XC = – 15.91 V 30 – 15.91 -28 o 33.96 I 1 nF R = 30 Z = 30 – j 15.91 Zmag = 33.96 -28 o

Non-Resonant Antenna (at 5MHz) XL (ohms) 5 f (MHz) – 31.82 + 31.42 L = 1 µH C = 1 nF f (MHz) Xc (ohms) 5 At 5MHz V I -0.7 o XL = + 31.42 XC = – 31.82 30 – 0.4 -0.7 o 1 µH 1 nF R = 30 Z = 30 + j 31.42 – j 31.82 = 30 – j 0.4

Resonant Antenna XL = – XC 1 2  f C 1 2  f C 2  f L 2  f L = = 1 At resonance, the inductive reactance and the capacitive reactance are equal in magnitude and opposite in sign. XL = – XC 1 2  f C 1 2  f C 2  f L 2  f L = = 1 2   (L C) f res = 1 2   (1 µH * 1 nF) f res = = 5.033MHz

Resonant Antenna (at 5.033MHz) XL (ohms) 5.033 f (MHz) – 31.62 + 31.62 L = 1 µH C = 1 nF f (MHz) Xc (ohms) 5.033 At 5.033MHz V XL = + 31.62 XC = – 31.62 30 I 1 µH 1 nF R = 30 0 o Z = 30 + j 31.62 – j 31.62 = 30 + j 0

AIM4170 Computations 1. Accurately measures the voltage, current and phase angle (theta) 2. Computes the resistance & reactance vectors, and the impedance 3. Computes the SWR, reflection coefficient, cable loss etc V I +57 o 30 + 46.93 +57 o 55.70 Z = 30 + j 46.93 Zmag = 55.70 Z = V / I SWR = Vmax Vmin

AIM4170 Block Diagram 5kHz – 180MHz

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

Impedance at the TX, Feeder and Antenna The feeder is really an impedance transformer TX Feeder ATU ZT = RT + jXT = 50 + j0 ZF = RF + jXF = 30 - j22 ZA = RA + jXA = 16 + j123

AIM4170 Measurement Points ANTENNA SYSTEM Feeder AIM4170 ZF = RF + jXF = 30 - j22 ZA = RA + jXA = 16 + j123

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

AIM4170 Functions - 1

AIM4170 Functions - 2

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

AIM4170 Component Measurement

Measuring Capacitance

Measuring Inductance

Tuned Circuit Resonance

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

20m Dipole (Courtesy Bob, W5BIG)

G5RV – 1-31MHz

G5RV on Top Band – coax feed

G5RV on Top Band – strapped feed (Marconi T)

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

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

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

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

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

Antenna Loading (Courtesy Steve, VK2ZSZ)

2kW Dummy Load 1-151MHz

2kW Dummy Load 1-151MHz

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

Crystal Parameters

Short Circuit

Distance to Fault (short circuit)

Tuning a Quarter-Wave Stub

Band Scan

Frequency Markers

Marker Data

Spreadsheet

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

Smith Chart

50-ohm Termination: 1.5m Feeder

Smith Chart: Cable Attenuation – 1.5m Feeder 40MHz 80MHz 70MHz 0.68 – j0.53 x 77.28 = 53 – j41

50-ohm Termination: 32.5m Feeder

Smith Chart: Cable Attenuation – 32.5m Feeder

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

Basic TDR

TDR Menu

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

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

AIM4170 ANTENNA ANALYZER End of Part 1 28 April 2011

This presentation is located at: AIM4170 ANTENNA ANALYZER Ian Wade, G3NRW g3nrw-radio@ntlworld.com This presentation is located at: homepage.ntlworld.com/wadei/aim4170.htm

AIM4170 ANTENNA ANALYZER Part 2 Ian Wade, G3NRW g3nrw-radio@ntlworld.com 8 September 2011 Copyright © 2010,2011 Ian Wade All Rights Reserved

AIM4170 Antenna Analyzer 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

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

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

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

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

80m Trap

80m Trap: Resonant Freq = 3.6913MHz

From the Antenna Handbook: The Dipole at 80m At 80m λ / 2 at 80m Balun B 3.6913MHz From the Antenna Handbook: B = λ / 4 at 3.69MHz = 67 ft 6 inches (20.574m)

80m Trap at 1.86MHz: Inductance = 9.18µH

The Dipole at 160m At 160m λ / 2 at 1.86MHz A Balun 67’ 6” 9.18 µH

Calculating the Required Wire Lengths - 1 67’ 6” 9.18 µH (Courtesy Martin, K7MEM)

Calculating the Required Wire Lengths - 2 67’ 6” 9.18 µH (Courtesy Martin, K7MEM)

The Finished 160m/80m Trap Dipole Design 238’ 6” 80m trap 80m trap Balun 51’ 9” 67’ 6”

Actual 160m/80m Dipole Results

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

Antenna System with Basic Feeder TX ATU

No resonance on 20m

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

Extra 1.5m feeder: resonance on 20m

No resonance on 20m

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

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

Extra 1.5m feeder: resonance on 20m

Original Feeder

The feeder is really an impedance transformer AIM4170 ZF = 30 - j22 ZA = 16 + j123

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

One Way to Read the Antenna Feedpoint Impedance AIM4170

Custom Scan The AIM4170 reverses out the feeder impedance transformation to obtain the antenna feedpoint impedance Feeder AIM4170 ZA = 16 + j123 ZF = 30 - j22 ZA = 16 + j123

Custom Feeder Calibration AIM4170 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.

Example: 50-ohm Resistive Load Feeder AIM4170 50 ohms ZA = 50 + j0 ZF = 62+ j1 ZA = 50 + j0

50-ohm Resistive Load: without correction ZF = 62 + j 1

50-ohm Resistive Load: with custom correction ZA = 49.3 + j 0.1

70MHz Groundplane: at feeder feedpoint ZA = 43 + j 0

70MHz Groundplane: at antenna feedpoint ZA = 31 - j 23

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

The ATU has to convert the feeder feedpoint impedance to 50 + j0 Conjugate Matching The ATU has to convert the feeder feedpoint impedance to 50 + j0 TX Feeder ATU ZT = 50 + j0 ZF = 30 - j22

ATU Matching (Courtesy Mike, WY2U)

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

AIM4170 Remote Control AIM PC AIM4170 AIM4170 AIM4170

AIM4170 Remote Control Remote AIM Netbook PC WiFi Connection AIM4170

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

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)

Remote Operation through Wireless RS-232 Link WiFi RS-232 Link www.vsc-x.com VSC-X to antenna under test

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

Analyzer Comparisons - 1 AIM4170 (Courtesy Bob, W5BIG)

Analyzer Comparisons - 2 AIM4170 £ 349 UK (Oct 2010) £ 449

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

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

UK Supplier Vine Antennas Ltd www.vinecom.co.uk

Some Related Links AIM Software and Documentation: www.w5big.com/prog_update.htm Comparisons between AIM4170 and other analyzers: www.bnk.com/w0qe/AIM4170_page1.html www.antennasbyn6lf.com/files/vna_comparisons.pdf Product Reviews, QST, August 2007 AIM Discussion Forum: aim4150.proboards.com/index.cgi RealVNC Remote Desktop Server: www.realvnc.com/products/free/4.1/index.html Interactive Tutorials on Transmission Lines, SWR, Smith Chart: www.fourier-series.com/rf-concepts/index.html Owen Duffy’s Experimenter’s Notebook: vk1od.net

RadCom Review July 2007

Some Related Books www.arrl.org/shop/The-ARRL-Antenna-Book Reflections III: by Walter Maxwell, W2DU w2du.com Antenna Topics: by Pat Hawker, G3VA www.rsgbshop.org/acatalog/Online_Catalogue_Antennas_37.html

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 (bob@w5big.com) www.w5big.com 160m Inverted L Plot, by Paul, VE7BZ (ve7bz@shaw.ca) www.bcdxc.org/ve7bz_160m_inverted_L_antenna.htm Hustler Antenna Plots, by Andy, M5ALA (andrew@amsnorthwest.co.uk) www.amsnw.myzen.co.uk/radiostuff.html Electrically Short Halfwave Dipole, by Martin, K7MEM (martin.e.meserve@lmco.com) www.k7mem.150m.com/Electronic_Notebook/antennas/shortant.html L/C Impedance Matching Network Design Tool, by Mike, WY2U (wy2u@optonline.net) Analyzer Comparisons, by Bob, W5BIG (bob@w5big.com) www.arraysolutions.com/Products/aim_comparisons.htm

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

This presentation is located at: AIM4170 ANTENNA ANALYZER Ian Wade, G3NRW g3nrw-radio@ntlworld.com This presentation is located at: homepage.ntlworld.com/wadei/aim4170.htm