DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
This simple AM transmitter uses a crystal-controlled oscillator and transistor stages to generate and amplify a stable RF signal, then modulates it with audio through a transformer. Powered by 12V, it offers a practical introduction to radio transmission using basic, easily available components.
This microphone audio compressor uses an LM324 op-amp with multi-stage amplification, diode-based gain control, and buffering to regulate signal levels. It smooths volume by reducing loud peaks and boosting weak input, improving clarity for voice, recording, and radio applications with a stable 12V supply
LILYGO T-Embed SI4732 combines an ESP32-S3 microcontroller with a DSP multiband radio (AM/FM/SW/LW + SSB), IPS display, and wireless connectivity — a compact programmable receiver for makers and radio enthusiasts.
This FT8 digital interface connects a computer to a transceiver using a USB sound card, audio transformers, and optocoupler-based PTT control. It enables clean audio exchange and safe isolation, allowing reliable weak-signal digital communication modes like FT8 through proper level control and synchronization.
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 micro power AM transmitter uses a crystal-controlled oscillator and a 2N2222 transistor stage to generate a stable RF carrier, then modulates it with audio input. A tuned tank circuit and variable capacitor optimize output, enabling low-power short-range broadcasting for experimentation and learning
This article explains how the HydraSDR RFOne enters the SDR market as a direct competitor to the Airspy R2, offering similar core performance with a few key differences.
It highlights a wide frequency range (24 MHz–1.8 GHz), 12-bit ADC, and up to 10 MSPS sampling, making it suitable for spectrum analysis and amateur radio use. The main differentiator is its open-source firmware, which allows customization and community-driven development
NOAA-15 & NOAA-19 shutdown in Aug 2025 ends APT signals. Hobbyists: explore Meteor-M2, GOES, & SDR skills to keep decoding weather satellites data.
Explore MSI-SDR — a budget wideband SDR receiver with 12-bit ADC, up to 8 MHz bandwidth, and multi-band inputs, offering hobbyists a cheap entry into RF spectrum analysis
This guide explains terminated antennas for HF ham radio, which use resistors to absorb reflected energy and maintain stable impedance across wide frequency ranges. It covers designs like Beverage and T2FD antennas, highlighting their broadband performance, directional patterns, and suitability for multiband, low-noise, and space-restricted installations.