Unraveling the End-Fed Halfwave Antenna

Join Ward Silver (N0AX) as he dives deep into the world of End-Fed Halfwave (EFHW) antennas! This presentation covers the EFHW's origins, key principles, and common misconceptions. Ward explains in-depth topics like impedance transformation, counterpoise considerations, and practical installation techniques for both fixed and portable setups. The presenter dives deep into the world of End-Fed Half-Wave (EFHW) antennas, a design that's gained popularity among amateur radio operators for its simplicity, versatility, and performance. Beginning with the historical roots of the dipole, the talk breaks down how the EFHW is not some exotic, standalone design, but simply a standard half-wave antenna fed at the end instead of the center. The presenter methodically walks through the impedance characteristics, the role of impedance transformers—especially the popular 49:1 ratio—and how current and voltage behave at different feed points. The audience gets a thorough comparison of center-fed, off-center-fed, and end-fed configurations, highlighting that all three are electrically the same antenna with different power application points. Practical considerations are also covered in detail, from grounding strategies and counterpoise options to installation tips for both portable and fixed stations. The presenter explains how coaxial cable shielding, chokes, and even environmental factors like nearby metal structures and elevation affect performance. Examples like using fishing poles for summits-on-the-air or trimming antennas to adjust resonance drive home the real-world utility. Whether it's running QRP from a picnic table or experimenting with capacitor loading for broader band coverage, the EFHW proves to be a flexible, reliable option—especially when built with a properly designed transformer and installed with a bit of thoughtful planning. This presentation was given at the January Dayton Amateur Radio Association (DARA) meeting.