DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
The HF category brings together all content related to high‑frequency bands, from 160 m through 10 m, with emphasis on practical antennas, propagation, and station hardware. Here you will find compact 40 m verticals, multiband wire antennas, HF QRP transmitters, SDR transceivers, and accessories designed for real‑world home and portable operation. Articles often include measured SWR curves, on‑air reports, and build photos so you can understand how a design will behave before you start cutting wire.
There is a strong focus on getting HF on the air from small Indian plots, apartments, and field locations without sacrificing too much performance. Whether you are preparing for your first HF QSO, improving your 40 m NVIS coverage, or chasing DX on higher bands during good conditions, this section provides tested ideas to upgrade your HF station step by step
Full-size Delta Loops for the 40-meter band normally require around 42 meters of wire—often impossible for operators with limited space. To overcome this challenge, Andy (2E1TAP) documented his attempt at constructing a space-efficient, shortened 40-meter Delta Loop.
Compact 4 m shortened vertical antenna for the 80 m band using a 64 µH loading coil and LC base matching network. UR0GT design enables efficient 3.65 MHz operation in small spaces with full-size radial system for strong HF performance.
The Alpha 1 release of the Nextion Emulator for CEC firmware — a Python-based emulator that brings full desktop simulation of CEC/uBITX radios with Nextion HMI.
LARCSet is a $39 open-source 40 m SSB/CW transceiver kit from HF Signals delivering 5 W QRP output with simple BITX-style architecture. Beginner-friendly build-it-yourself radio designed to make affordable HF operation accessible to new and homebrew amateur radio operators.
Common-mode currents are a well-known enemy of clean RF communication. When RF travels along the outside of your coaxial cable, it causes feedline radiation, noise pickup, RFI in the shack, audio distortion, and unpredictable SWR variations. To solve this, radio amateurs typically install a CMC choke (also called a current balun or common-mode filter) at […]
Ditch the lossy traps and discover the Morgain Antenna—a clever, compact dual-band dipole for 40m and 80m. Operating at just 20 meters long, this wire-only design uses folded elements to achieve resonance without bulky coils. The ultimate space-saving solution for your HF station
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.
Low on space but want to reach the 80m band? This technical guide walks you through building a shortened Inverted V antenna for 3.700 MHz. Using high-inductance loading coils, you can fit a full 80m radiator into a restricted urban footprint while maintaining a low SWR
Build the legendary G5RV multiband antenna with this comprehensive DIY guide. Discover the technical balance between the 102ft radiator and the critical matching section that allows for 80m–10m operation. Learn how to optimize your feedline and avoid common RFI “growing pains”
Looking for an effective HF antenna for a high-rise or apartment balcony? This practical guide from VU3DXR details the construction and performance of a Loaded Loop Antenna—a compact, high-efficiency solution designed specifically for radio amateurs facing severe space constraints.