1. David Conn VE3KL OARC Nov 2006 1 Balun Design using Chokes David Conn VE3KL RG8-X 6 Metre Choke

2. 6/2/2016David Conn VE3KL OARC Nov 2006 2 Acknowledgements QCWAChapter 70 Members Dave Green VE3TLY Ben Price VE3CDA Doug Leach VE3XK Ray Parsons KG2B

3. 6/2/2016David Conn VE3KL OARC Nov 2006 3 Background on Balun’s Balanced-to-Unbalanced Transmission Line Transformers Basic TYPES Choke type.. a simple coil of coax..my talk Ferrite Core … Ruthroff, Guanella designs Ferrite Beads… over the coax Bazooka. Quarter wave coupling stubs

4. 6/2/2016David Conn VE3KL OARC Nov 2006 4 Purpose of the Talk To show what a Choke does for you To give you the actual design information All Design Information in the RAC Web Site and TCA Jan/Feb 2007 RAC Hotlinks 2007 Jan-Feb RAC Calculators (VE3KL Coil Calculator)

5. David Conn VE3KL OARC Nov 2006 5 The Problem SWR? Unwanted Radiation Television Interference Uncontrolled Antenna Pattern Noise Received From Vertically Polarized Sources RF in Radio Shack Power line noise

6. David Conn VE3KL OARC Nov 2006 6 SWR with a Choke

7. David Conn VE3KL OARC Nov 2006 7 SWR Without a Choke EZNEC Simulation

8. David Conn VE3KL OARC Nov 2006 8 The Solution A “Good Choke” Isolation Plane

9. David Conn VE3KL OARC Nov 2006 9 How is a “Good Choke” Designed ? (Not by using 10 turns of coax with a diameter of 6 to 8 inches!)

10. David Conn VE3KL OARC Nov 2006 10 VE3KL Coil Design Calculator Coil Theory InductanceMaxwell 1873 Skin EffectLamb 1883 InductanceWheeler 1928 CapacitanceGrandi 1999 Insulator Thickness Length Diameter Nr. Turns Pitch Air Core Design

11. David Conn VE3KL OARC Nov 2006 11 Frequency Response of the Choke Ideally, put the resonant peak in the band center. 21 MHz Keep the Coil Reactance Greater Than 1500 Ohms

12. David Conn VE3KL OARC Nov 2006 12 VE3KL Design Graphs/Tables Three Methods Select a single band design… dimensions not fixed….a compromise Select a single band optimized design…dimensions fixed Select a multi-band design…dimensions fixed… a compromise

13. David Conn VE3KL OARC Nov 2006 13 Example of A Single Band Design…15 Metres 20 Turns, 56 mm Reactance Greater Than 1500 Ohms

14. David Conn VE3KL OARC Nov 2006 14 Example of A Single Band Design..2 Metres 10 Turns,53 mm

15. David Conn VE3KL OARC Nov 2006 15 Examples of Single Band Optimized Designs

16. David Conn VE3KL OARC Nov 2006 16 Examples of A Multi Band Designs

17. 6/2/2016David Conn VE3KL OARC Nov 2006 17 Which Design? Select the Single Band design when size is important…..my Hamstick 20 m Dipole Select an Optimized Single Band Design when performance is paramount not Size….a Mono Band Beam Select a Multi Band Design for your Tri Band Beam and others

18. 6/2/2016David Conn VE3KL OARC Nov 2006 18 Coaxial Cable Issues ? MIL Spec and Amateur Types Bending Radius Waterproof ? Connectors? Specifications not complete Foam core vs. solid core Dielectric properties of the outer jacket?

19. 6/2/2016David Conn VE3KL OARC Nov 2006 19 Summary? Chokes Clean up your antenna system Many Designs available on the RAC Web Site Models use state of the art algorithms MF Chokes get very large VHF Chokes get small Transmission Line Chokes needed for UHF and above

20. David Conn VE3KL OARC Nov 2006 20 Mr. Problem SWR? Wanted for recycling Television Interference Uncontrolled Antenna Pattern Noise Received From Vertically Polarized Sources RF in Radio Shack NO Power Line Noise

21. David Conn VE3KL OARC Nov 2006 21 VY 73 David VE3KL Build One for Your Next Antenna