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OXO QRP HF Transmitter

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The  OXO QRP HF transmitter  is a simple, low-power CW (continuous wave) transmitter designed by George Burt, GM3OXX. It is a single-band transmitter that can be built to operate on any of the amateur radio bands from 160 to 20 meters. The transmitter is built around a few standard transistors and a crystal oscillator. It is an elementary circuit to build, and can be assembled from a kit or from scratch. Fig: OXO QRP HF Transmitter The OXO transmitter is a QRP HF transmitter, which means that it produces a very low output power. This makes it ideal for making short-range contacts with other amateur radio operators. The OXO transmitter can also be used for experimentation and learning about radio electronics. OXO QRP HF Transmitter
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Getting Started with AIS: Track Ships from Your Shack with a RTL-SDR

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The  Automatic Identification System (AIS)  is a VHF radio-based collision-avoidance protocol that virtually every commercial, passenger, and large recreational vessel in the world is required to carry. Since 2004, the International Maritime Organization (IMO) has mandated AIS transponders on all ships of 300 GT or more engaged in international voyages, all cargo ships of 500 GT or more on domestic routes, and all passenger ships regardless of size. Every few seconds — sometimes as often as every two seconds when a vessel is manoeuvring — its AIS transponder transmits a compact digital burst on one of two dedicated VHF channels:  161.975 MHz (Channel 87B)  and  162.025 MHz (Channel 88B) . That burst contains a rich data payload: MMSI number (a unique vessel ID), ship name, call sign, IMO number, vessel type, dimensions, draught, destination, navigational status, GPS position, course over ground, speed over ground, rate of turn, and more. Getting Started with AIS...
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Shortened & Compact HF Dipoles

Do it Yourself 80M Trapped Dipole Antenna The 80 m trapped dipole provides 80‑metre coverage plus additional HF bands without needing full‑size wire lengths. By inserting resonant traps, the overall span shrinks while still presenting a reasonable match to common rigs. The article covers trap construction, wire cutting, support height and measured SWR data, making it accessible even for first‑time builders. Short Linear Loaded Ham Radio Band HF Antenna This short linear‑loaded antenna uses closely spaced conductors to emulate a longer HF element in a much shorter overall length. It is aimed at city hams who cannot fit full‑size dipoles yet still want acceptable efficiency and bandwidth. The project discusses layout, loading pattern, tuning with simple tools and expected performance compared to standard wires. GM4JMU Shortened Dipole Antenna: Compact Performance for HF Bands The GM4JMU  shortened dipole  is a proven compact HF design that cuts overall span while retaining respe...
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Khanfar Spectrum Analyzer: A Free RTL-SDR Tool Suite Worth Knowing

Khanfar Spectrum Analyzer: A Free RTL-SDR Tool Suite Worth Knowing : A detailed look at the Khanfar Spectrum Analyzer free RTL-SDR tools covering real-time FFT, wideband scanning, CFAR , IQ recording, and radio direction finding
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Meshcore for Ham Radio: A Simple Start

Meshcore for Ham Radio: A Simple Start : Explore Meshcore for ham radio: a low-power, LoRa-based mesh network for local messaging. A complete, impartial guide on hardware, flashing, uses, and limits
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Build a High-Sensitivity Regenerative Receiver with 2N7000 MOSFET

Build a High-Sensitivity Regenerative Receiver with 2N7000 MOSFET : DIY Circuit for 2N7000 regenerative receiver with air-core and ferrite coils. Includes band coverage tables, regeneration theory, and practical tuning tips
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FT2 Digital Mode in 2026 — The Fastest Thing on HF and What the Community Really Thinks

FT2 Digital Mode in 2026 — The Fastest Thing on HF and What the Community Really Thinks : FT2 digital mode reviewed in 2026 — 3.8-second cycles, real shack experiences, technical trade-offs, and whether it deserves a place in your station
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