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This project introduces the Loggi, a hybrid antenna merging the wide frequency coverage of log-periodic dipole arrays (LPDA) with the high gain and front-to-back ratio (F/B) of Yagi antennas. Traditional LPDAs span broad frequencies with moderate gain and low VSWR, while Yagis provide high gain and F/B over narrow bands. By analyzing high-Tau LPDA designs, it was found they could nearly match the gain of VHF/UHF Yagis while maintaining excellent patterns, F/B, and front-to-rear ratios (F/R). Optimizing specific elements for target frequencies (e.g., 144.1 MHz) led to the Loggi, which uniquely features all driven elements without passive directors or reflectors. This design effectively functions as a narrowband optimized LPDA, with front elements acting like Yagi directors and rear elements like Yagi reflectors, thus enhancing gain and directional characteristics while retaining broad frequency versatility.

SkyRoof is an open-source, 64-bit Windows application designed for amateur radio operators and satellite enthusiasts, combining satellite tracking and Software Defined Radio (SDR) functionality in a unified platform. The software provides real-time satellite tracking, pass predictions, and visual representations through Sky View, Earth View, and Timeline displays. It features an SDR-based waterfall display covering VHF/UHF satellite segments with Doppler-corrected frequency scales, automatic satellite labeling, and visual tuning capabilities. SkyRoof supports various SDR devices (Airspy Mini, SDRplay, RTL-SDR), external transceiver CAT control, and antenna rotator integration. The application automatically downloads satellite data from SatNOGS and other sources, offers voice announcements for satellite passes, and includes comprehensive frequency control with Doppler tracking, manual corrections, and RIT functionality for enhanced satellite communication operations.

Learn about the design and construction of a hybrid low-pass filter for HF transmitters, specifically tailored for operation in the 6 meter band. The filter utilizes a single elliptic link for high cutoff steepness and deep VHF/UHF suppression, requiring only two standard capacitor values. The article discusses the necessity for improved filtering due to changing technological landscapes and the increasing sensitivity of VHF/UHF radio channels to interference from various sources. Detailed circuit schematics and performance characteristics are provided, ensuring minimal degradation of antenna system VSWR when integrating the filter into the setup.

G6HKS Yagi Kits & Parts provides material kits for building high-performance PowAbeam Antennas, ideal for VHF/UHF enthusiasts interested in DXing. The kits feature advanced Yagi designs, including the unique ParAclip system, ensuring exceptional all-weather stability and minimizing detuning effects. With resources, tips, and support, the site aims to make antenna construction straightforward for amateur radio operators. The focus is on delivering top-tier performance at competitive prices, empowering users to build and enjoy their own high-quality antennas.

This page offers a tool for hams to design vertical antennas for portable use on different HF/VHF/UHF bands. Vertical antennas provide omni-directional transmission and reception, making them ideal for DX contacts. By adjusting the antenna's dimensions and viewing radiation patterns and VSWR charts, hams can optimize performance in various terrains. The tool also accounts for the impact of sloping ground on elevation radiation patterns. Perfect for hams looking to enhance their portable radio setups and improve long-distance communication.

This project details an automatic roger beep circuit for VHF/UHF contests. Built around a Microchip PIC microcontroller, the design detects PTT (Push-To-Talk) activation and generates a brief tone upon release, mimicking a "roger beep" to signal the end of transmission. The circuit utilizes readily available components and includes downloadable resources for PCB layout and firmware.

Operating amateur radio repeaters involves understanding frequency offsets, CTCSS tones, and the basic signal flow through a repeater system. This resource details the fundamental concepts of repeater operation, including the distinction between input and output frequencies, the role of **CTCSS (Continuous Tone-Coded Squelch System)** for access, and the typical frequency bands utilized for local communication. It clarifies terms such as "simplex" versus "duplex" operation and provides a diagram illustrating the signal path from a handheld transceiver to a repeater and back to another station, emphasizing the range extension repeaters offer. The article further explains practical aspects like identifying a repeater's offset (e.g., +600 kHz for 2-meter band) and the necessity of programming the correct tone. It compares the operational benefits of using repeaters for local communication over direct simplex contacts, highlighting how repeaters overcome line-of-sight limitations. The content is structured to assist new licensees in confidently making their first repeater contacts, providing a foundational understanding of how these critical infrastructure components facilitate wider area coverage for VHF/UHF amateur radio.

Learn how an experienced ham radio operator designed and built a compact shack in their motor home. Discover the considerations, challenges, and solutions involved in setting up a radio station in a small space without damaging the vehicle. Find out which radios were chosen for VHF/UHF scanning, HF communications, and QRP operations. Get insights on cabinet design, speaker placement, and radio cabling for a functional and portable ham radio setup on the road.

This comprehensive article dispels common misconceptions about Standing Wave Ratio (SWR) in amateur radio. The author explains that SWR is not an antenna property but a measure of the entire antenna system, representing the mismatch between transmission line and load impedance. Contrary to popular belief, modest SWR values (under 3:1) typically cause minimal power loss in HF applications. The article demonstrates mathematically why obsession with achieving 1:1 SWR is often unnecessary, explains when SWR matters more (QRO, QRP, VHF/UHF), and explores effective matching techniques including proper ATU placement and quarter-wavelength transformers.

A guide to constructing a simple quarter-wave ground plane antenna, detailing design principles and providing dimensions for VHF/UHF bands

This article explores the role of velocity factor (VF) in calculating stub lengths for VHF/UHF Baluns. It clarifies misconceptions about VF's relevance, distinguishing between coaxial cable interior fields and external stub fields. Practical examples, such as the Pawsey Stub and Coaxial Cable Balun, are analyzed alongside experimental findings. The results reveal that traditional VF adjustments are unnecessary for stubs with external fields but critical for internal coaxial applications. Historical and theoretical insights provide a comprehensive perspective for antenna enthusiasts and designers.

INTERCOM is a freeware application designed for remote control of KENWOOD TMD700/710/V-71 transceivers, as well as other transceivers equipped with UP, DOWN, and PTT commands. Compatible with Windows XP and higher (32 & 64-bit), INTERCOM offers multilingual support in English and French, and can be used on Linux, Ubuntu, or Android platforms via WINE 1.0 or CROSSOVER. The software enables users to send basic commands—such as selecting TX, VFO, memory channels, or power levels—either through manual inputs or over a TCP/IP link. INTERCOM is tailored for SIMPLEX setups, facilitating the interconnection of VHF/UHF repeaters with nearby repeaters. Remote commands are transmitted using DTMF codes, which are decoded by SIMPLEX and forwarded to INTERCOM via TCP/IP. This functionality makes INTERCOM an ideal tool for radio enthusiasts and operators seeking seamless remote management of supported transceivers in simplex configurations.

Version 1.0.1.0 of QW5 Lizard, released on September 21, 2019, is a specialized logging program designed for Windows notebooks, particularly for outdoor operations and contest participation. It supports individual configuration and input masks, making it suitable for various HF and VHF/UHF contests. The software prioritizes data security, with a planned feature for live upload directly to the GMA database, catering to activations of references such as mountains, WCA, lighthouses, and WWFF. This logging tool offers robust export capabilities, including EDI for NAC and IARU Region 1 Contests, as well as standard ADIF and Cabrillo formats. The program has undergone extensive testing and deployments by various stations, demonstrating its utility in real-world contest scenarios, such as the Holzhammer Contest. Future extensions for specific contests are also anticipated, enhancing its versatility for the competitive ham radio operator.

Terrestrial Amateur Radio Packet Network An ever expanding group of Amateur Radio operators are working together to use many VHF/UHF radios to link multiple ham radio stations in a digital network for the purpose of having fun in a fun, educational, hobbyist-controlled environment, built using ham radio infrastructure based on packet radio technology.