DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
Explore AM HF transmitter circuits and DIY ham radio projects, including Class-C and QRP transmitters, modulation techniques, and practical circuit guides. Learn how to build simple AM transmitters and experiment with HF radio electronics for amateur radio enthusiasts and homebrew builders.
The tag page features projects and articles related to low-power AM transmitters and HF radio experimentation, designed for hobbyists interested in building their own radio equipment.
This Class C AM transmitter uses a high-efficiency amplifier where the transistor conducts for less than half the signal cycle, achieving around 70–80% efficiency. It combines an oscillator, buffer, and IRF510 MOSFET power stage to deliver about 5 W RF output, making it suitable for compact amateur radio transmission.
This simple two-stage AM transmitter uses an oscillator and a transistor RF amplifier to deliver about 1 W output on HF bands. It supports common transistors like BD139 or 2N3553, uses a modulation transformer for audio input, and serves as a beginner-friendly QRP project with stable performance
Build a Simple Series Modulated AM QRP HF Transmitter for the 40m or 80m bands. This DIY guide includes a stable crystal oscillator schematic, series modulation tips, and power amplifier details for low-power (QRP) ham radio operation.
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