DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
The radio category groups together posts that are about complete radios and operating rather than individual circuits—transceivers, receivers, handhelds, SDR rigs, and real‑world operating notes. You’ll find write‑ups on rigs like Curumim, sBitx, ZBitx, Baofeng UV‑5R Mini, uBITX experiences, and other commercial or homebrew radios, often with a strong “how it actually behaves on the bands” focus.
The ATS Mini receiver has long been a favorite among hobbyists and Shortwave Listeners (SWLs) for packing incredible functionality into a tiny, portable package. Now, the latest iteration, the ATS Mini V4, arrives on the scene, building on the success of its predecessors (V1, V3, and V3S) with significant enhancements that cement its status as a top-tier micro-controlled radio.
From the smallest Wi-Fi chip antenna to the largest High-Frequency (HF) wire arrays, radio antennas are the crucial link between your radio and the airwaves. They are marvels of physics, yet decades of folklore have created persistent myths that trip up even seasoned operators.
Shortened G5RV antenna design: a compact multiband HF dipole covering 20m–6m bands with ladder-line matching and 4:1 balun for portable or small-yard installs.
Pocket SI4735 Dual Core Decoder firmware upgrade adds 400 kHz waterfall, improved SSB/CW/RTTY decoding, and faster scanning — transforming the ATS Mini into a powerful DSP pocket receiver.
DIY EFHW antenna for 40 m–10 m: a 10.1 m multiband end-fed wire with 34 µH loading coil and 49:1 UNUN matching for portable HF and limited-space stations
Build the Shorty Forty — a compact 7 MHz dipole using center-loaded coils to shrink a 40 m antenna to 25 ft while maintaining resonance and solid HF performance in limited space
The GM4JMU shortened dipole uses loading coils to deliver full 40 m band performance in under 10 m span. Ideal compact HF antenna for small gardens, rooftops, and portable ham radio installations.
KV4P-HT turns an Android phone into a VHF/UHF ham radio via USB-C — an open-source ESP32 + SA818 transceiver add-on with APRS messaging, 1 W output, and fully off-grid operation
On the evening of 3 October 2025, radio listeners across Tamil Nadu were pleasantly surprised: broadcasts soon resumed on the Medium Wave frequency 1548 kHz using the high-power transmitter in Trincomalee, Sri Lanka — the same facility that formerly belonged to Deutsche Welle (DW). What We Know The test broadcast started at 8:00 PM IST […]
New Quansheng UV-K5/UV-K6 radios use a PY32 MCU incompatible with STM32 firmware — flashing custom firmware can brick the radio, making MCU identification critical before updates