The Mighty Mite 40 Meter QRP CW Transmitter is a legendary low-power Morse code transmitter widely built by amateur radio operators for portable, minimalist, and educational operation.
HF
The HF category brings together all content related to high‑frequency bands, from 160 m through 10 m, with emphasis on practical antennas, propagation, and station hardware. Here you will find compact 40 m verticals, multiband wire antennas, HF QRP transmitters, SDR transceivers, and accessories designed for real‑world home and portable operation. Articles often include measured SWR curves, on‑air reports, and build photos so you can understand how a design will behave before you start cutting wire.
There is a strong focus on getting HF on the air from small Indian plots, apartments, and field locations without sacrificing too much performance. Whether you are preparing for your first HF QSO, improving your 40 m NVIS coverage, or chasing DX on higher bands during good conditions, this section provides tested ideas to upgrade your HF station step by step
Getting Started with FreeDV: A Beginner’s Guide to Digital Voice on Amateur Radio
Beginner’s guide to FreeDV digital voice on HF using an SSB transceiver, computer, and sound-card interface. Learn setup, operating basics, and how open-source Codec2 delivers clear voice communication under weak-signal conditions
Building Sovina 40M Class E CW Transmitter with BS170 MOSFETs
Build the Sovina 40 m Class-E CW transmitter using BS170 MOSFETs and 74HC02 logic for efficient 7 MHz QRP operation. High-efficiency switching PA delivers 4–7 W output with clean RF and simple crystal-controlled design for homebrew HF rigs.
Tree Mounted Quarter-Wave Vertical Antenna
Field-expedient quarter-wave vertical antenna suspended from a tree using only two sloping radials. Compact HF design provides low-angle radiation, near-50 Ω match, and portable deployment for emergency and outdoor ham radio operation.
LinHT SDR: Open-Source Linux-Based Handheld Software Defined Radio for Amateur Enthusiasts
Software Defined Radio technology has revolutionized base station infrastructure, laboratory-grade receivers, and bench equipment for years, yet handheld transceivers have stubbornly clung to traditional fixed-function architectures. The LinHT SDR shatters this paradigm entirely, delivering a genuine software-defined transceiver in a genuinely portable package.
Building a Double Bazooka Antenna for HF and VHF Ham Bands
The double bazooka antenna, often described as a coaxial dipole, is a time-tested antenna design widely used by amateur radio operators. Its popularity comes from a combination of simple construction, predictable impedance behavior, and noticeably lower received noise compared to thin wire dipoles.
Microphone Pre-Compressor Circuit for SSB Transceivers
Clean, punchy audio is critical for effective SSB communication, especially when operating QRP or low-power HF transceivers. A microphone pre-compressor placed ahead of the transmitter’s audio input can significantly improve average modulation levels without introducing harsh distortion. The attached Microphone Pre-Compressor circuit is a practical, discrete-component design well suited for homebrew and experimental SSB rigs.
Simple Speech Processor for Homebrew SSB Transceivers
Simple speech processor for homebrew and QRP SSB transceivers that boosts average talk power while preserving natural audio. BF245 mic preamp, dynamic compression stage, and TL071 output amplifier improve readability and on-air presence.
Microphone Preamplifier with Diode Clipper for SSB Transceivers
Simple microphone preamplifier with diode clipper to boost and limit SSB audio for amateur radio transceivers. Prevents over-modulation, improves speech clarity, and delivers clean transmit audio in DIY HF radio setup
Multiband Dipole Antenna for 10–80 Meters
Compact multiband HF dipole covering 10–80 m using symmetrical loading coils and coax matching section. Single-wire antenna for small spaces enabling 80, 40, 20, 15, 11, and 10 m operation with an antenna tuner.