G3TXQ Choke Charts

The late Steve Hunt (G3TXQ) contributed a great deal of excellent technical study work for amateur radio. One of his achievements was to produce charts for HF common mode choking. He discovered the popular air centre coil of coax (often known as the 'Ugly Balun') was not as effective as many believed. Using easily available Fair-Rite 43 sized toroid ferrites of different materials he performed a series of experiments to show where each combination best 'choked' common mode currents. I present the latest known (2017) version of these charts. In simple terms you're looking for a combination that shows a green bar and black underline on the bands of use.