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Chris, I don't think a resource like that exists. Perhaps a short paragraph or two can be found in the classic text "Transmission Line Transformers" by the late Jerry Sevick W2FMI. Ross' instructions are buried somewhere in a huge thread. If I can locate his post I will forward a link. The crux of his teaching is this: The value of a binocular core over a simple toroid stems from the nearly complete enclosure of the winding wires in a surrounding of magnetic material. Winding inductance per length of wire is maximized and leakage inductance is minimized. To get the full value of this though Ross reminds us that the wire must everywhere be snug up tight against the core material. Sloppy loops hanging out where the wire is exposed at the ends of the apertures for example contribute to flux escaping into space rather than remaining confined in the core. Leakage inductance and poor coupling results Ross recommended winding the tapped primary first, secondary later. He suggests finding the center of the primary wire by folding it and using that as the starting point for winding, building out a half turn at a time, and using a thin? stick-like plastic tool to press the wires and force them to conform tightly to the core material, both inside the apertures,? and at the outer wrap, and to lay neatly next to the previously wound wire. The secondary is overlayed on the primary maintaining the tight neat conformance by using the plastic tool. It does make for a measurably better transformer. Neatness counts here. The twisted pair approach also forces primary and secondary into tight mutual conformance, and provides a shielding mechanism that reduces flux leakage. It also builds windings with an intrinsic transmission line property that is useful in achieving broad bandwidth. That is where Sevick's book can provide additional insight. I hope you find that useful, OM! 73, JZ KJ4A? On Thu, Sep 14, 2023, 7:09 PM Chris <chris.rowland@...> wrote:
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