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
The halfwave end fed antenna is an attractive option for many radio amateurs as it is able to provide multiband operation without the use of traps or stubs whilst occupying a minimum amount of space. A broad-band matching network is typically used to transform the high impedance of the EFHW feed point to 50Ω suitable […]
This pippin QRP transmitter is basically a conventional colpitts type crystal oscillator with output taken from a low value collector load resistor and direct coupling is made into the base of PNP transistor used as an amplifier. This simple circuit develops around one watt output with 12V as power supply. At the heart of this […]