Loop Tuner - Racetrack Coupler

IntroductionThe racetrack tuner is a capacitive coupler for short transmitting loop antennas. The name is refering to its racetrack form.Racetrack Circus Maximus in Rome - maybe I should call it ’Maximus Tuner’ :-)For use by certified HAM operator - use at own risk and keep fingers away from banana connectors when transmitting.FeaturesIt is built with two independently controlled capacitors (around 10 - 170 pF) for Matching and Tuning. Each capacitor is manually controlled by 12 turn knobs with indicator dials 00.0 - 11.9. At endpoints the knobs use slip clutch to protect the device from deformation.It has low loss with minimum of cabling inside. The capacitors share same stator where Tune capacitor is on outside and the Match slides inside stator eliminating cables. It has been tested up to 100W@3MHz, designed to withstand 40kV with 1mm thickness of PLA. Only use uncoloured PLA for capacitors as pigment can significantly increase loss and heat.BuildPrinting and building instruction: B