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Chameleon Knowledge Base · The Complete Online HF Antenna Handbook

What Is Open-Wire Feed Line?

Learn what open-wire feed line is and why it provides exceptionally low loss for multiband HF antennas.

Feed Lines & RF Components Balanced Transmission Lines Reviewed 2026-07-14
Short Answer: Learn what open-wire feed line is and why it provides exceptionally low loss for multiband HF antennas.

Explanation

Overview Open-wire feed line is a balanced transmission line consisting of two parallel conductors separated by air using periodic spacers. It offers some of the lowest transmission losses available for amateur radio antenna systems. Because air is the primary dielectric, open-wire feed line is highly efficient, particularly on the HF bands. Characteristics Balanced transmission line. Very low attenuation. Excellent high-SWR performance. High power capability. Advantages Outstanding efficiency. Minimal transmission loss. Excellent multiband capability. Ideal for balanced antennas. Installation Requirements Maintain adequate spacing from conductive objects. Avoid sharp bends. Keep conductor spacing consistent. Support the line without compressing the conductors. Typical Applications Doublets. Center-fed dipoles. Balanced multiband antennas. High-power HF stations. Applied to Chameleon Products Open-wire feed line is an efficient option for certain balanced antenna designs and educational experiments that complement the broader range of Chameleon HF antenna systems. Related Articles What Is Ladder Line? What Is a Balun? What Is Feed-Line Loss? What Is Characteristic Impedance? Relate

The exact result depends on the complete station: frequency, geometry, feed line, matching network, return-current path, environment, operating power, and the reference plane of any measurement. A low SWR establishes an impedance relationship at that point; it does not by itself prove efficiency, radiation pattern, compatibility, or safety.

What to Verify

  • Use the newest official product guide or primary service documentation.
  • Confirm the exact model, revision, components, configuration, and operating conditions.
  • Begin tests at low power and change one variable at a time.
  • Do not infer compatibility from connector or thread fit.

Learn Next

  • Antenna Selection: A Mission-First Decision Guide
  • Engineering Design Tradeoffs in Portable HF Antennas
  • Antenna Measurement Reference Planes
  • Understanding Common-Mode Current

Source note: Independently synthesized with reference to The ARRL Handbook for Radio Communications, 99th edition (2022), and The ARRL Antenna Book for Radio Communications, 24th edition (2019). Verify changing regulations, services, software, specifications, availability, and safety requirements against current primary sources.