DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
A collection of amateur-radio HF projects and guides covering multiband wire antennas (dipoles, loops, verticals, G5RV, EFHW), matching transformers, compact antenna solutions, and HF homebrew equipment for operation across the shortwave bands (≈3–30 MHz)
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.
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
DIY 80 m magnetic loop antenna: 1.5 m copper tubing loop with gamma-style feed and air-variable capacitor, delivering low-noise 3.5 MHz HF performance in small areas
Explore the sBitx v3 — an open-source Linux SDR transceiver merging computer and HF radio, enabling portable digital operation without a laptop
Limited on space but want to get on 40m? Learn how to build a high-performance, reduced-size 40m antenna using high-Q loading coils. This guide covers calculations, coil winding, and tuning techniques to fit a 20-meter band antenna into a compact 10-meter footprint.
This simple CW transmitter uses a 74HC240 buffer IC as both oscillator and driver to generate a stable RF signal around 7.023 MHz. A crystal ensures frequency accuracy, while keying enables Morse transmission, making it a compact, low-power QRP project for beginners.
This series-modulated AM transmitter uses a simple low-power design where the audio signal is applied directly to the power supply of the RF oscillator, causing the carrier amplitude to vary and produce AM. It uses a crystal oscillator for stable frequency and is ideal for beginners learning basic radio transmission concepts.
Looking for a fun weekend project? Discover the OXO QRP transmitter—an elegantly simple, high-performance HF rig perfect for homebrew enthusiasts and minimalist radio operators
The GEK 2x SSB Transceiver is a Mid range high performance Low-noise, low cost SSB HF transceiver. The local oscillator is stable DDS VFO and DDS BFO/Carriers oscillator. The Power amplifier is designed as a push-pull Mitsubishi the latest generation of 12V-30MHz Silicon MOSFET Power Transistor. The RD06HHF1 is used in the pre driver and […]