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Family Tree of Antennas David Conn VE3KL

Family Tree of Antennas David Conn VE3KL. Acknowledgements. Doug Leach VE3XK Bert Barry VE3QAA QCWA Members The Inventors References given in slides ARRL Antenna book. Why Make a Family Tree. To understand the overall (complex) picture To enable us to select a good antenna

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Family Tree of Antennas David Conn VE3KL

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  1. Family Tree of AntennasDavid Conn VE3KL Acknowledgements Doug Leach VE3XK Bert Barry VE3QAA QCWA Members The Inventors References given in slides ARRL Antenna book

  2. Why Make a Family Tree • To understand the overall (complex) picture • To enable us to select a good antenna • To organize and compare existing designs Antenna Types

  3. Antenna Types 1…6 • Resonant Wires: Dipole, Yagi, Quad, Vertical, Moxon Square ……. • Long wires (non-resonant): Zepp/G5RV… • Resistively Loaded: Beverage, Pennant, Rhombic … • Small Loops/Wires: Resonant Loading Circuits

  4. Antenna Types 1…6 5. Phased Arrays: Yagi, Collinear, Sterba Curtain, Rhombic, Four Element Rectangular Array, Many Others … • Lens Antennas for UHF/Microwaves: Parabolic Dish, Helix … Family Tree

  5. Radiation Waves Circuits Transmission Lines Ground/Ionosphere Transmitting Antennas Power Receiving Antennas SNR Amateur Radio Antennas (index) Simulation/Smith Chart Microwave UHF/VHF MF HF

  6. Transmitting Antennas • Performance measured by Gain & Directivity • Low Loss: Transmitter Matching • SWR of 2:1 loses half the power • Ground/Ionosphere… dominates • Polarization (Vertical for MF Transmitters)

  7. Receiving Antennas…SNR • Performance measured by RDF (dB) • RDF (Receiving Directivity Factor) defined as peak response in desired direction to average response in all directions • Ground/Ionosphere… extremely important • Consider Polarization: VHF weak signal (DX) uses Horizontal Polarization Antenna Examples

  8. MF AntennasNeed good S/N…not Gain for Receive • Inverted L, T • Beverage Antenna… the best? • Terminated loops (Pennant, Flag) • Vertical Phased Arrays • Vertical GP antennas • K9AY Loop • 4 Square Vertical Green indicates Receive Only Antenna

  9. Inverted L,T,Vertical,K9AY Antennas http://www.antennex.com/preview/archive3/ltv.htm http://www.aytechnologies.com/TechData/LoopInstall.htm

  10. MF Receiving Antenna Performance RDF, dB Vertical phased array B/S 13 2 Broadside Beverages 1.75 W Good Beverage 1.0 W 8.64 Small 4X4 Square Dipole Flag/Pennant K9AY 80 m high Vertical Omni Beverage 0.5 W Bad 5.0 Cost Low Dipole http://www.w8ji.com/antennas.htm

  11. Classic Dipole: type 1 .. Elevation Plot 35 feet Ground RDF = 8.3 dB Good

  12. Classic Dipole: type 1 .. Azimuth Plot

  13. Classic Vertical Ground Plane: type 1 RDF =5 dB

  14. Two Element Quad…Azimuth: type 1 RDF = 12.84 dB…high 31 feet high to top

  15. End Fed Zepp Antenna: type 2

  16. MF Pennant…Receive only: type 3 • Ground independent • Very Low Gain (-35 dB) • RDF = 7.39 dB…OK • Cardoid pattern • F/B 25 dB • Small..20 feet each arm • Terminated loop class

  17. Small Magnetic Loop Antenna: type 4Very High Voltages g3ycc.karoo.net/loop.htm

  18. Microwave Antenna Array: type 5 & 6Space Diversity Transmitter Receivers Wanted Rays Unwanted Rays Arrays

  19. Arrays • Driven arrays: Collinear, Sterba and Bobtail Curtains, two dimensional arrays, three dimensional (lens) arrays, Log Periodic • End fire or broadside or any beam shape • Parasitic arrays: Yagi

  20. Linear Arrays (Driven)Directivity increases with Length

  21. Four Element Rectangle.. Easy to Visualize ARRL Antenna Book

  22. Collinear Arrays http://www.tpub.com/neets/book10/42i.htm

  23. Bobtail Curtain Driven ArrayMaximum Gain 4.5 dBiLow Angle Radiation ARRL Antenna Book

  24. Log Periodic Antenna Array…looks like a tapered Yagi but each element is driven • Very Broad Band • Dimensions repeat logarithmically • QST Sept. 2002 ARRL Antenna Book

  25. VHF/UHF/Microwave Antennas • Yagi, Quagi, Quads ….stacked versions • Cycloid Dipole… Circular Polarization..Repeaters • Helix and Helix Arrays • Vertical, Jpole • Corner Reflectors, Parabolas, Lenses • Circuit board patch antenna arrays

  26. The J Pole Antenna: type 1 • Easy to Build • No ground plane needed • Many designs available http://www.cebik.com/jp2.html

  27. Cycloid DipoleCircular Polarization…Repeaters: type 1 http://www.wa7x.com/cycloid_info.html

  28. Summary • Tree must include antenna design as well as the physical description • Tree must include: ground effects, basics of the ionosphere • Tree must link to the most important well proven designs • Tree must help amateurs at all levels to select an appropriate antenna

  29. Many Thanks: Especially to the Organizers http://www.dxlc.com/solar/

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