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.
Hotel Antenna for 2 Meter and 70 Centimeter Amateur Bands
The Hotel Antenna is a clever space-saving vertical antenna design popular among VHF and UHF amateur radio operators. It is especially useful for radio amateurs living in apartments, hostels, or temporary locations where installing large outdoor antennas is not practical.
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.
Hourglass Loop Antenna : A Stealthy Performer for VHF and UHF
If you’re hunting for a high-performance antenna that doesn’t look like a metallic porcupine, the Hourglass Loop (popularized by KE4ERO) is a fantastic weekend project. It is essentially two delta loops stacked and fed in-phase, resulting in a bidirectional pattern with about 5 dB of gain over a standard dipole.
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
J-Pole Antenna Using 300 Ω TV Ribbon Line
DIY 300 Ω twin-lead J-pole antenna for the 2 m band offering efficient VHF performance, easy coax feed, and portable installation without radials
Twin-Lead J-Pole Antenna for VHF and UHF Amateur Radio
Build a simple twin-lead J-pole antenna for VHF/UHF using 300-ohm ribbon cable. This end-fed half-wave vertical with quarter-wave matching stub delivers omnidirectional coverage, low noise, and reliable FM/repeater performance without ground radials