DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
Detailed technical guides for building and deploying high-performance HF wire antenna. This section covers a wide range of designs, including end-fed half-waves (EFHW), off-center fed dipoles (OCFD), G5RVs, and long-wire antennas. Learn how to optimize your antenna for specific bands, understand the role of 49:1 and 9:1 ununs, and discover methods for effective antenna tensioning and weatherproofing
Unlock elite DX performance with the Switchable Delta Loop. This detailed guide covers everything from the 141-foot 40m foundation to the ingenious 18-inch tuning tails that enable seamless 30m operation. Perfect for hams seeking a low-angle radiator with a manageable footprint
The Doublet Dipole remains a favorite for hams seeking multiband efficiency without complex hardware. By utilizing balanced feed lines and a 4:1 balun, this antenna design overcomes the limitations of traditional coax-fed dipoles. Our guide breaks down the essential formulas and provides a detailed dimension table for the 80m, 40m, 20m, and 15m amateur radio bands for your next project.
The Half Square has been quietly delivering low-angle DX gain to operators who know about it, while remaining invisible to everyone else — including curious neighbours. Shaped like the Greek letter π, it uses two quarter-wave verticals fed in phase through a half-wave horizontal section, matches directly to 50-ohm coax without a tuner, needs no radials, and can beat an Inverted-V by 4 dB toward the horizon. Here is everything you need to build one
If you are running a multiband doublet or any antenna with a tuner, ladder line will outperform coax on almost every band. Here is how to build your own from scratch — four proven designs, common materials, and every practical detail from spacer drilling to routing it through the shack wall.
A simple length of wire can unlock nearly the entire HF spectrum—and that’s exactly what the multi-band doublet antenna delivers. Using low-loss ladder line and an antenna tuner, this classic balanced antenna provides efficient coverage from 6 m through 160 m without the complexity of multiple resonant dipoles. Whether installed in a backyard or deployed in the field, the doublet remains one of amateur radio’s most versatile and enduring wire antenna solutions.
Learn how a fan dipole (parallel dipole) antenna lets you operate on two HF bands from a single feedline with no tuner. Includes the 468 formula, component breakdown, band pairing tips, and step-by-step building guide
The Extended Lazy-H antenna is one of amateur radio’s classic wire antenna designs, combining simplicity with reliable multiband performance. First published in the October 1955 issue of QST magazine, this antenna was intended to provide efficient HF operation using balanced construction and open-wire feed line.
Can’t fit a full-sized 80-meter dipole in your backyard? Or maybe you’re tired of the high noise floor of a vertical? It’s time to look at the Half-Loop. This “open-loop” design provides a fantastic balance between the quiet reception of a loop and the simplicity of a wire antenna.
In this project, we explore a multiband Half-Loop configuration that covers everything from 80 meters down to 15 meters. We’ll discuss the radiation pattern, the importance of a good ground or counterpoise, and how to use a simple tuner to jump between bands. If you’re looking for a “stealthy” antenna that punches above its weight on the low bands, this build is for you. Let’s get that wire in the air!
This article explains the construction, operation, and real-world usage of a 9:1 impedance transformer (UN-UN) for long wire and random wire antennas, making it ideal for SWL listeners and amateur radio operators.
The W5GI multiband collinear antenna combines wire radiators and coaxial phasing sections to deliver reliable HF coverage from 80–6 m. A tuner-friendly alternative to the G5RV with strong multiband performance and efficient radiation for practical ham radio installations