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

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

6/2/2016David Conn VE3KL OARC Nov 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

6/2/2016David Conn VE3KL OARC Nov 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)

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

David Conn VE3KL OARC Nov SWR with a Choke

David Conn VE3KL OARC Nov SWR Without a Choke EZNEC Simulation

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

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

David Conn VE3KL OARC Nov 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

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

David Conn VE3KL OARC Nov 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

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

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

David Conn VE3KL OARC Nov Examples of Single Band Optimized Designs

David Conn VE3KL OARC Nov Examples of A Multi Band Designs

6/2/2016David Conn VE3KL OARC Nov 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

6/2/2016David Conn VE3KL OARC Nov 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?

6/2/2016David Conn VE3KL OARC Nov 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

David Conn VE3KL OARC Nov 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

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