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Chameleon Knowledge Base · The Complete Online HF Antenna Handbook

Understanding the Off-Center Feedpoint

The OCF40 feed point is deliberately offset: one wire leg is about 44 feet and the other about 22 feet. That asymmetry creates the multiband impedance behavior the matching transformer is designed to handle.

Advanced Antenna Theory CHA OCF40 Reviewed 2026-07-14
Start with the real operating role: The OCF40 feed point is deliberately offset: one wire leg is about 44 feet and the other about 22 feet. That asymmetry creates the multiband impedance behavior the matching transformer is designed to handle.

How the documented system works

The transformer connects the two wire terminals to the BNC feed line while also carrying the center suspension load through its dedicated hole. Either leg may attach to either wire connector, but both exact legs are required.

The boundary that prevents mistakes

Off-center feeding does not mean arbitrary wire lengths or a universal match. Height, angle, surroundings, coax, and tuner range affect the final SWR, and the transformer does not replace safe strain relief.

Use this field sequence

Keep each original leg on its own winder, identify the 44- and 22-foot wires during inspection, suspend the transformer from its hole, leave slight wire sag, and measure the final geometry before transmitting.

Source boundary

CHA OCF40 User Guide 250513. The exact guide, product state, complete feed path, geometry, and safety limits control. Connector fit does not prove electrical or structural compatibility.

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