A Collaborative Hands-on Club Project

From bare toroids to finished baluns – on Sunday, May 17, 2026 – RARA and the Greater Beloit Amateur Radio Club (GBARC) took on a hands-on 49:1 balun build for an end-fed half-wave antenna. It was a team effort and it was great fun with 19 “builders”.

The Build Team & Pre-build Prep

While at a GBARC meeting, the topic went to “do we want to do another build project this year”, in 2025 we collaborated on a Tape Measure Antenna Build and Fox Hunt and it was great fun. Chuck WD9BB, presented an exciting idea – let’s build 49:1 Un-Uns! He presented his idea and research and was a natural organizer for the project – so off we went! All parts were identified and purchased, the team pre-drilled the boxes, planned for soldering, and testing. We were on our way! Many thanks to team members: Larry AC9GO, Dean K9FLO, Brian KD9QVB, Jimmy KC9GOL, and Greg K9GJN. Special thanks also to Larry K9KZT for securing the shelter!

Build Day

Wrapping of the toroids, mounting into the enclosure, connecting leads to the SO-239s, and soldering! Prepping for soldering was critical!

Testing

Un-Uns were tested and if they didn’t test within spec, trouble shooting and modifications were made to bring to success!

A good time was had by all and the team is already planning for next year!

This year’s build project coordinated by the Rockford Amateur Radio Association (RARA) and the Greater Beloit Amateur Radio Club (GBARC) is a 49:1 Un-Un impedance transformer for End Fed Half Wave (EFHW) antenna rated at 100 W. A kit has been assembled that includes everything you need to get started: a pre-drilled enclosure, all hardware, toroid and wire for wrapping.  The build team will provide hands-on guidance for winding your own toroid, which is the key component that creates the impedance match that makes the EFHW antenna work.  

The finished antenna will cover 80 through 10 meters for the 80-meter version, or 40 through 10 meters for the 40-meter version. Experienced builders will be on hand to walk you through every step of the assembly. Note:  The kit does not provide the wire you will need to cut for your target band and a counterpoise to match.  While you will need to provide the wire to complete your antenna, you will not need to bring it to the event unless you would like guidance.  (14-gauge stranded wire is recommended and you will need approximately 166 ft for 80-meter and/or 66 ft for 40-meter).

Sorry all kits are now taken! But you can still come out for a great time!

• Date: Sunday, May 17, 2026
• Time: Swap Meet & Social at 9:00 AM; Build session begins approximately 12:30 PM and continues until finished
• Location: Hononegah Forest Preserve (Indian Rest Shelter), Rockton, IL
• Lunch: A hot dog lunch will be provided after the Swap Meet (or bring your own)
• To Register:  email Verna W9YUM at w9yum.vs@gmail.com and let her know you plan to attend
• Be sure to mark your calendar and get registered.
• On behalf of the RARA and GBARC build team – we look forward to seeing you!