DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
The Transmitter category focuses on RF circuits that actually put a signal on the air: from simple QRP rigs and short‑range AM broadcasters to more advanced HF drivers and linear stages. You’ll find classic experiments like the Ten Minute QRP transmitter and Mighty Mite, educational HF and short‑wave transmitters, as well as modern solid‑state designs such as Class‑C AM transmitters and IRF510 push‑pull power amplifiers.
Each article explains the full RF chain in practical language—oscillator, buffer, driver, PA, filtering, and modulation—so you see how the blocks fit together instead of just copying a schematic. Wherever possible, circuits are crystal‑controlled or otherwise stabilised, with notes on heatsinking, harmonic suppression, legal use, and how far you can realistically expect to be heard. Whether you want to understand the theory behind AM and CW transmitters, build a low‑power beacon, or develop the RF stages that will later become a full transceiver, this section gives you proven starting points and measured results to guide your experiments.
Ready to go on a “Fox Hunt”? Whether you are tracking down a hidden transmitter for a local Ham radio competition or trying to find a mysterious source of RFI in your shack, you need a tool that is more sensitive than a standard field strength meter.
Learn how to build a compact, high-sensitivity Miniature FM Transmitter with this DIY electronics guide. Featuring a simple transistor-based schematic and an electret microphone, this project is perfect for beginners exploring RF circuits and wireless audio.
Build a high-sensitivity DIY 3-Transistor FM Bug Transmitter using a piezo microphone. This step-by-step guide includes a stable schematic, BC547 transistor tips, and frequency tuning advice for crystal-clear long-range audio monitoring.
There is something magical about hearing your own voice or music coming through a vintage tube radio from across the room—or across the neighborhood. While many low-power “flea” transmitters struggle with range, this 3-Watt AM monster brings some real “punch” to the Medium Wave band.
In this project, we’re stepping up the power. Using the classic BD139 transistor and a rock-steady crystal oscillator, we’ll build a transmitter that balances simplicity with performance. Whether you’re a Part 15 enthusiast or just want to experiment with AM modulation, this circuit is the perfect way to become your own local broadcaster. Let’s get on the air!
Build a simple 40 m CW transmitter using a 2N2222 and 7 MHz crystal oscillator — a minimalist QRP design with keyed oscillator and low-pass filter for clean HF Morse transmission.
If you’re a radio electronics enthusiast or hobbyist, building a Simple FM transmitter using readily available components like BC547 transistors can be both fun and educational. This compact circuit transmits voice signals captured via an electret microphone to a standard FM radio receiver, making it perfect for short-range audio transmission projects. Simple FM Transmitter – […]
This blog post dives into a detailed DIY IRF510 AM transmitter circuit using the IRF510 MOSFET, perfect for radio enthusiasts and electronics hobbyists
Simple 80 m CW transmitter using a 3.58 MHz ceramic resonator for frequency stability and MOSFET power stage — ideal first HF QRP build for beginners
A crystal controlled FM transmitter is a radio frequency (RF) circuit that uses a quartz crystal oscillator to generate a stable, precise frequency for FM radio transmission. Unlike simple LC oscillator circuits, crystal-controlled transmitters offer superior frequency stability and accuracy, making them ideal for applications requiring consistent performance.
Are you interested in radio electronics? This simple FM band transmitter circuit offers an excellent starting point for beginners and hobbyists. You can build this transmitter using common electronic components and start broadcasting on the FM band.