CLICK HERE TO REGISTER for OARC End-Fed Half Wave Antenna Build Workshop
The End-Fed Half Wave (EFHW) Antenna Build Workshop will be of interest to anyone who has a multi-band HF amateur radio with up to 100 Watts of transmitting power. Assemble a 49:1 Un-Un transformer in mounting hardware with a SO-239 feedline connector, and optionally connect an antenna wire suitable for 80/40/30/20/17/15/12/10m or 20/17/15/12/10m bands.
Date: 31 May 2026
Time: 13:00-17:00
Cost: Non-members pay $10 more
[] $75 – EFHW Antenna workshop with Un-Un transformer only, no antenna wire
[] $85 – EFHW Antenna workshop with Un-Un transformer AND 34’ antenna wire (20/17/15/12/10m bands, suitable for portable use)
[] $120 – EFHW Antenna workshop with Un-Un transformer AND 132’ antenna wire (80m band, also resonant on 40/30/20/17/15/12/10m, suitable for permanent installation)
Location: Scouts HQ (1345 Baseline Rd Ottawa, ON K2C 0A7, Canada)
CLICK HERE TO REGISTER AND PAY FOR THE END-FED HALF WAVE ANTENNA BUILD WORKSHOP
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WORKSHOP OUTLINE
1. Introduction
Definition and Purpose: An End-Fed Half-Wave (EFHW) antenna is a popular resonant wire antenna designed to be one half-wavelength long at its lowest operating frequency. Unlike a center-fed dipole, it is fed at the end, providing high installation convenience, and it naturally resonates on both odd and even harmonics of that base frequency.
Basic Components: 49:1 Un-Un transformer, feedlineconnector, mounting hardware, antenna wire
2. Design and Construction (overview of tools, materials and techniques)
Materials Supplied: 2 x 240-43 torroids; 100 pF capacitor; 14-gauge enameled wire; PVC junction box; cable ties; SO-239 and misc. hardware.
Construction Techniques: PVC junction box will be pre-drilled
3. Hands-On Building Session (assembly and troubleshooting)
Practical Assembly: Participants build their own 49:1 Un-Un transformer in PVC junction box under supervision, applying the techniques learned.
Troubleshooting: Guidance on common issues that may arise during construction and how to resolve them.
4. Testing and Tuning (performance testing, tuning techniques)
Performance Testing: Instructions on how to test the Un-Un and antenna’s performance using SWR meters and other tools.
Tuning Techniques: Methods for adjusting the antenna for optimal performance, including compensation coil, coax counterpoise, middle-of-wire capacitor
5. Conclusion and Q&A (wrap up and open discussion)
Wrap-Up: Summary of key points covered in the workshop.
Open Forum: Opportunity for participants to ask questions and share experiences related to EFHW antennas.