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G/T (Gain-to-Noise Temperature) is a critical figure of merit for evaluating the receive performance of VHF/UHF antennas, particularly for weak-signal work like EME (Earth-Moon-Earth) or meteor scatter. This resource presents extensive simulation data for numerous 2-meter and 6-meter Yagi antenna designs, originally compiled by _VE7BQH_ (Lance Johnson). The lists, updated as of October 2017, include various antenna models from designers such as _DK7ZB_, G0KSC, and K1FO, providing key performance parameters. Each entry details the antenna's G/T value, gain, front-to-back ratio, beamwidth, and VSWR at specific frequencies like 144.1 MHz or 145.0 MHz. The data facilitates comparison of different Yagi configurations, including those with folded dipoles and varying intrinsic impedances, aiding radio amateurs in selecting optimal antennas for their specific operational needs on the 2-meter and 6-meter bands.

Presents a detailed resource for DXers interested in Non-Directional Radiobeacons (NDBs), MF, HF, and VHF propagation beacons, and various other radiobeacon types. The site offers access to downloadable information files, including an Abbreviations List, NDB List Country List, and NDB Publications List, which serve as foundational materials for newcomers to the hobby of beacon monitoring and DXing. It covers specialized topics such as DGPS beacons, GMDSS DSC mode, and NAVTEX mode, with dedicated sections providing in-depth explanations. A Beacon Photo Gallery showcases diverse radiobeacon types from around the globe, offering visual context for different systems encountered in the field. The platform also facilitates participation in unique monthly Coordinated Listening Events (CLEs), providing guidelines and schedules for these activities. The resource outlines various associated Groups.io lists, including the primary NDB List for radiobeacons (NDBs, Propagation Beacons, VOR systems), the DGPS List for DGPS DXing, Time Signals, LORAN, and WeFAX modes, and specialist groups like NavtexDX and DSC List for GMDSS-DSC. It details how to join these communities for further engagement and information exchange.

The **KC0KJF** personal amateur radio page provides a collection of resources for fellow hams, particularly those interested in operations within southwest Missouri. It offers detailed listings for **Missouri repeaters** on both 2 meters and 70 centimeters, serving as a practical reference for local VHF/UHF communication. The site also includes information about the operator's station setup and antenna projects, such as a dipole and a bazooka antenna, which can offer insights into basic antenna construction and deployment. Beyond local repeater data, the page features links to the FCC Part 97 rules, essential for understanding amateur radio regulations. The operator, licensed as a Technician Class since April 16, 2001, shares his journey from Citizen's Band Radio to amateur radio, driven by a lifelong fascination with shortwave listening. This narrative provides context for the resource's focus on practical operating information and foundational regulatory knowledge. Additional content covers specific equipment like the 2-meter/70-centimeter Arrow Antenna, useful for hams considering portable or fixed station VHF/UHF setups.

**LDG Z100** automatic tuner repair focuses on toroid replacement and troubleshooting. The guide provides detailed steps for diagnosing and fixing common issues with the toroid, which is crucial for the tuner's performance. It includes specific instructions on disassembling the unit, identifying faulty components, and sourcing replacements. The document is technical, requiring familiarity with electronic components and soldering techniques. It emphasizes the importance of using the correct toroid specifications to ensure optimal functionality. Successful repair of the **LDG Z100** ATU restores its ability to match a wide range of antennas, enhancing transmission efficiency. The guide compares the performance before and after the repair, highlighting improvements in SWR readings and overall reliability. Practical application of this repair extends the life of the tuner, making it a cost-effective solution for amateur radio operators. The document serves as a reference for similar repairs on other models, providing insights into common issues and solutions. It is a valuable resource for those looking to maintain their equipment without resorting to professional services.

A home made field strength meter wit detailed pictures and schematic diagram by W4ZT

HB9BZA's LoTW users list, originally compiled since 2005 from DX-Cluster and user submissions, now primarily leverages the official ARRL full users list released on July 29th, 2017. This resource details 228,012 calls across 340 current DXCC entities, with the latest update noted on March 2, 2026. It offers various formats, including a full list, text versions, and breakdowns by country, providing valuable insights into LoTW participation for DXers. While the ARRL's official list with "last upload" dates diminished the original list's unique utility, HB9BZA's site continues to offer statistics and user counts by country, which remain of interest. The author, HB9BZA, expresses gratitude to contributors who helped maintain the list's accuracy over many years, achieving an impressive 96.4% match with the ARRL's data before the official release. Knowing which stations are LoTW active encourages more hams to join the system, demonstrating that even rare DXCC entities like Ducie Island or Heard Island can be confirmed quickly. For instance, HB9BZA recounts a 36-minute QSL confirmation for a 3A2MW contact. The list also integrates with the RXCLUS packet radio/telnet client, enhancing DXCC award tracking by identifying LoTW participants and utilizing upload dates for alarms.

The NB6Zep Antenna, an electrically shortened 80-meter end-fed wire, addresses space constraints for low-band operation by integrating two loading coils into a 37-foot wire. This design, modeled with _EZNEC_, explores configurations like the quarter-wave sloper and inverted-L, with the latter providing a more vertical radiation pattern and practical backyard deployment. The resource details specific coil construction, recommending 21 uH coils made from _BW coil stock #3026_ or similar, and outlines wire segment lengths for optimal tuning. Performance analysis indicates a radiating efficiency of approximately 27% with good ground conductivity, resulting in a signal typically 3-4 dB down compared to a full-size quarter-wave vertical. The antenna exhibits a narrow bandwidth, around 50 kHz, due to its high Q, necessitating a tuner for broader band operation. Feedpoint impedance is low, with ground resistance playing a critical role in achieving a usable SWR. The article emphasizes the importance of an effective ground rod at the feedpoint for proper operation and tuning, suggesting an antenna analyzer for precise adjustments. It confirms the antenna's suitability for DX, citing successful contacts from Oregon to the East Coast and Hawaii on a 160-meter variant, making it a viable option for urban operators seeking low-angle radiation on 80 meters.

The club was established in 1975 with the purpose to further the exchange of information and cooperation between members, to promote knowledge, to prepare for service in the community in time of disaster or need for emergency communications,

On this page are designs for Dual Band 2M / 70cm antennas. All antennas are 50 ohm designed driver. These Yagis have a unique element called a Open Sleeve. 4 Element 5 element and 9 element Dual Band - 2M / 70cm antenna projects

The function of the XPhase is based on the fact that the interfering signal, received by an auxiliary antenna, is added phase-shifted to the signal received from the main antenna. When the phase-shift is more or less 180°, the interfering signal is canceled out.

The article presents a detailed examination of 40-meter wire antenna performance, specifically focusing on the impact of antenna height on gain and radiation patterns. It quantifies how a 40-meter dipole at 1/8 wavelength above ground exhibits a high-angle radiation pattern, while raising it to 1/2 wavelength significantly lowers the take-off angle, improving DX capabilities. The author, VE3VN, leverages _EZNEC_ simulations to illustrate these changes, providing visual representations of the antenna's lobe structure at different elevations. Comparing a single dipole to a two-element wire array, the analysis shows that a 2-element array at 1/4 wavelength height can achieve **3.7 dBd** gain, outperforming a single dipole at the same height. This gain is further enhanced to **5.7 dBd** when the 2-element array is elevated to 1/2 wavelength, demonstrating the practical benefits of optimizing both element count and height for improved signal strength and directivity on the 40-meter band. The findings offer practical insights for hams seeking to optimize their wire antenna installations.

Demonstrating the construction of a short dipole antenna tailored for the 60 meter band, this resource provides detailed instructions for radio enthusiasts with limited space. The design incorporates inductive loading using two inductors (L1/L2) made from PVC tubes, allowing for effective operation on 5 MHz. The antenna consists of 12 meters of wire, divided into four sections, with specific dimensions and materials outlined for optimal performance. Results from users indicate that this antenna can significantly enhance DXing capabilities on the 60 meter band. Feedback from operators suggests that while the design is effective, adjustments may be necessary based on individual setups, such as coil diameter and wire gauge. Many users report successful construction and operation, with some experimenting with variations to improve resonance. The practical application of this antenna design has led to successful contacts and improved signal quality, making it a popular choice among 60 meter band operators.

Two coupled PAs with each 2 times 2C39 deliver around 400W RF.

This article describes the details of the design, which can be easily scaled for just about any HF band. The antenna described in this article is for the 20 meters band.

Analysis of N3UJJ installed antennas using the AIM4170b Antenna Analyzer

Effectively teaching amateur radio licensing classes requires more than just technical knowledge; it demands strong pedagogical skills and organizational acumen. This guide addresses the practical aspects of conducting successful amateur radio courses, emphasizing the instructor's role as an educational manager rather than merely a knowledge dispenser. It explores various class organizational structures, including traditional weekly sessions and _hybrid_ full-day formats, noting that many small meetings are often preferable for student engagement. The resource also provides strategies for finding suitable class locations, from public libraries and community centers to navigating public and private school systems, highlighting the importance of stressing the public service aspect of amateur radio to potential hosts. Key sections delve into effective classroom management, stressing the importance of preparation, a structured routine, and creating a comfortable learning environment. It details the VARK learning styles (Visual, Aural, Read/write, Kinesthetic), advocating for teaching methods that engage multiple senses to enhance student comprehension. The guide also offers advice on breaking down complex technical material, defining unfamiliar vocabulary, and making theoretical concepts practical through real-world examples. It includes a sample entry-level license syllabus covering topics like the nature of amateur radio, technical basics, transmitter/receiver fundamentals, and antennas, providing a framework for instructors to build their curriculum.

List compiled by N4LCD with description of main frequency usage

This useful coax tester allows you to screw the PL-259 onto the tester to get a GO/NO GO status. When the LED lights up- you have a short circuit.

A noncommercial site operated by Max Robinson and dedicated to passing on and preserving knowledge of vacuum tube circuits and techniques.

Experiences with the end-fed dipole based on the concepts presented by J. Taylor in an article titled RFD-1 and RFD-2: Resonant Feed-Line Dipoles in QST. August 1991.

DragonOS is a linux distribution dedicate to Software Defined Radio. It leverages the portability, security, and power of Lubuntu Linux as a delivery package and operating environment for a pre-installed suite of the most powerful and accessible open source SDR software. DragonOS has verified support for a range of inexpensive and powerful SDR hardware, including RTL-SDR, HackRF One, LimeSDR, BladeRF, and many others.

Port of the popular VOACAP program, HF propagation prediction tool. It may be compiled using the GCC GFortran compiler

Software Defined Radio parts, RTL-SDR DVB-T USB Stick, cables, antennas, upconverters, leds delaer

The only worldwide amateur radio repeater directory. Supports Android, iPhone, web, RT Systems, CHIRP GPS enabled. AvMap, Garmin, TomTom

Article on RTL SDR dongles to receive UHF VHF ham radio bands

Linux for shortwave and amateur radio monitoring. Supports popular SDR hardware and online streaming from KiwiSDR, WebSDR, and Spyserver sites. Articles about using Linux with your SDR devices.Skywave Linux, an innovative operating system, leverages cutting-edge technology for seamless access to radio signals globally. Ideal for regions with limited internet access, it effortlessly connects to a network of SDR servers, offering high-performance SDR operation without the need for extensive hardware. With pre-installed and configured SDR software, Skywave Linux simplifies signal discovery and operation for all users.

A DIY Automatic Band Decoder (ABD) project, designed for dual-radio operation, addresses the common challenge of integrating band data with older transceivers lacking dedicated outputs. This particular build utilizes an AVR AT90S8515 microcontroller and a 16x2 Liquid Crystal Display (LCD) to provide band information, specifically targeting Kenwood rigs via a computer's LPT port. The design aims for cost-effectiveness while maintaining functionality, offering a solution for hams seeking to add automatic band switching capabilities to their station without significant expense. The project outlines the core components required, including the microcontroller, LCD, and an enclosure, noting that the Printed Circuit Board (PCB) fabrication and AVR programming might present challenges for some builders. It details the input requirements, such as a four-pin input and PTT for each radio, along with a 13.8V DC power supply. The decoder provides 2x6 outputs capable of sinking 500mA, suitable for controlling external devices like antenna switches or filters. Despite the original unit being damaged by a lightning strike in 2004, the author confirms its successful operation prior to the incident and mentions plans for a revised version. The resource includes a schematic in PDF format and images of the finished PCB and assembled unit, demonstrating the practical implementation of the design.

The m0xpd keyer project utilizes a PIC16F628A microcontroller, offering Iambic A and B modes, adjustable speed from 5 to 40 WPM, and variable weight control. It incorporates a sidetone generator with adjustable frequency and volume, along with a PTT output for transceiver control. The design includes a 16-pin DIL IC socket for the PIC, a 3.5mm stereo jack for the paddle, and a 3.5mm mono jack for the PTT output. Powering the keyer requires a 9V DC supply, which is regulated down to 5V for the PIC. The circuit board layout is designed for through-hole components, facilitating home construction. A detailed schematic and a parts list are provided, guiding builders through the assembly process. The project also discusses the firmware programming for the PIC16F628A, essential for the keyer's functionality. Construction details cover component placement and wiring, ensuring proper operation. The keyer's compact size makes it suitable for portable or shack use, providing a reliable CW interface.

A simple charger designed for charging 12 V sealed lead acid batteries, used by radio amateurs for portable operation Amp-Hr Class used by radio amateurs for portable/emergency operation.

Local amateur radio clubs often serve as vital hubs for hams to connect, share knowledge, and participate in group activities. The Orleans County Amateur Radio Club (OCARC), operating under the callsign WA2DQL, provides a focal point for amateur radio operators in Albion, New York, and the surrounding Orleans County area. These organizations frequently host events, offer technical assistance, and foster camaraderie among members, supporting various aspects of the hobby from contesting to emergency communications. OCARC's activities include discussions on proposed Technician class privileges for **80, 40, and 15 meters**, indicating an interest in regulatory changes affecting entry-level licensees. The club also promotes the use of online tools like _Radio Mobile Online_ for antenna pattern analysis and _VOACAP Online_ for propagation predictions, aiding members in optimizing their station performance. Furthermore, OCARC highlights participation in _Parks On The Air_ (POTA) events, such as the Erie Canal Bicentennial Celebration in 2025, encouraging outdoor operations and public engagement with amateur radio.

On-line resource that provides practical battery knowledge for engineers, educators, students and battery users alike. The papers address battery chemistries, best battery choices and ways to make your battery last longer.

Established around 1968, the Wichita Amateur Radio Society (W.A.R.S.) N5WF provides a central hub for amateur radio operators in the Wichita Falls, Texas area. The society actively supports local ham radio interests, fostering community engagement and technical development among its members. W.A.R.S. is known for its commitment to public service communications and promoting the amateur radio hobby through various activities and educational initiatives. The society's activities often include field operations, technical presentations, and participation in emergency communications drills, which align with its mission to support the amateur radio community. Members frequently engage in _DXing_ and _contesting_, sharing their experiences and knowledge to help others improve their operating skills. The club also maintains local repeaters, providing essential infrastructure for regional communications.

This resource details the construction of a Moxon rectangle antenna, a two-element wire beam, drawing inspiration from a _QST_ article by Allen Baker, KG4JJH, and a project group led by KD6WD. It outlines the use of _AC6LA_ software for critical measurements (A-E) to design the antenna for specific bands like 17 meters, emphasizing the simplicity of adjusting frequency and wire size. The guide covers material selection for spreaders, such as telescoping fiberglass fishing poles, and various hub constructions, including aluminum tubing and PVC joints, with accompanying images. The author shares practical insights from building multiple Moxons for 10, 15, 17, and 20 meters, noting consistent 1:1 SWR at design frequencies and broadbanded performance. It describes the feedpoint assembly using a 1:1 Yagi current balun and wire nuts for robust, adjustable connections. The resource also discusses element insulators made from Lucite strips and attachment methods to spreaders using plastic wire ties and duct tape, ensuring precise element spacing. Performance observations include significant signal improvements (4-5 S units) over quad loops and a unique "DX-Vane" effect where the suspended antenna self-aligns with the strongest DX signal. The author also recounts an unsuccessful attempt at a dual-band 17/20 meter Moxon, concluding that the Moxon is inherently a monoband antenna, supported by _EZNEC_ plots for a 17-meter design.

A source of knowledge for learning about and understanding antennas. The goal is to present a comprehensive tutorial on antennas.

Operating the _Icom IC-746_ HF/VHF transceiver often presents specific technical questions, and this resource compiles a comprehensive Frequently Asked Questions (FAQ) document in an ASCII text format. It details common inquiries and solutions related to the rig's functionality, accessories, and potential modifications. The content is structured into distinct sections addressing general information, power supplies, antennas, microphones, keyers, amplifiers, TNC integration, and optional IF filters. The FAQ provides practical guidance on topics such as configuring the internal automatic antenna tuning unit (ATU), selecting appropriate power supplies, and understanding microphone pin-outs. It also delves into advanced subjects like computer control via CI-V, wiring for PSK31 operation, and troubleshooting common issues like low S-meter readings on 2m FM or loose tuning shafts. Specific questions cover the installation of optional IF filters, comparing Inrad versus Icom filters, and optimizing filter combinations for various modes. Furthermore, the document outlines various hardware and firmware modifications, including those for increasing monitor volume, replacing LCD driver transistors, and implementing a "poor man's TCXO." It even touches upon untested modifications, such as replacing PIN diodes in the demodulator. The FAQ also lists manual errata and discrepancies, offering a robust knowledge base for IC-746 owners seeking to optimize their station or resolve operational challenges.

The W6NL Moxon Yagi is a high-efficiency two-element 40m Yagi that uses cross elements to provide both loading and Moxon coupling, addressing the challenge of deploying a directional antenna on the 40-meter band. This resource details the transformation of a _Cushcraft XM240_ Yagi into this Moxon configuration, replacing the original loading coil LCA sections with four new assemblies. The guide provides comprehensive instructions for building the boom and elements, including specific dimensions for new sections and tee loading elements, along with detailed drawings and a full parts list for the conversion. Performance data indicates the converted antenna achieves **10.73 dBi** gain at 7.050 MHz with 99.5% efficiency and a high front-to-back ratio. The VSWR bandwidth is over **300 kHz**, ensuring good performance across a significant portion of the 40m band. Construction involves reinforcing element sections, attaching tee loading elements with U-bolts, and implementing element guying using materials like _Phillystran_ to manage sag and maintain structural integrity.

Make and automatic antenna tuner based on Arduino and using economic card. This ATU Project can be installed outdoors and controlled remotely by an rs485 link

This online database, called HAMLOG, can be used free of charge by any radio amateur worldwide.

Pictures and detailed instructions on installation of the LightningBolt Quad antenna

Demonstrates the swift setup process for a **Trans World Antenna**, showcasing its utility for portable amateur radio operations. The video highlights the antenna's design for quick deployment, a critical factor for activations like Summits On The Air (SOTA) or Parks On The Air (POTA), where efficiency in establishing a station is paramount. It illustrates the physical components and the sequence of assembly, emphasizing ease of use in varied field environments. The antenna system is presented as a multi-band solution, capable of operating across various HF frequencies. This adaptability makes it a versatile choice for hams engaging in outdoor activities or emergency communications. The visual demonstration provides practical insights into managing the antenna elements and feedline for optimal performance during temporary deployments. The focus remains on the practical aspects of field setup, rather than detailed technical specifications or performance metrics.

The ARRL Contest Results Database serves as a centralized repository for official scores and detailed breakdowns from numerous ARRL-sanctioned operating events. This resource typically features comprehensive listings of participants, their submitted logs, and final standings across different categories, modes, and bands. It allows hams to review their performance, compare results with other operators, and analyze contest trends over time, providing valuable insights into competitive amateur radio. Historically, the database has showcased the efforts of thousands of contesters, from single-operator entries to multi-operator, multi-transmitter stations. While the current status indicates scores are not immediately available, the database's primary function is to archive and present the outcomes of events like the ARRL DX Contest, Sweepstakes, and Field Day. This historical data is crucial for tracking individual progress, identifying top performers, and understanding the competitive landscape within the amateur radio community.

Supplier and exporter of generator, diesel generator, petrol generator, industrial generator, silent generator, power generator, electricity generator, gas generator, air cooled generator, gensets 1kva, 2kva, 5kva, 10kva, 50kva, 100kva, 250kva

An automatic band decoder made into a nice enclosure with LED indicators for the chosen band

The page provides detailed instructions on how to build a 60 meter End Fed Half Wave Antenna Tuner, with large pictures and diagrams. It is aimed at amateur radio operators looking to construct their own antennas for the 60 meter band.

Effects and intereferences caused by LED lights in the shack

A 2x3-foot laminated world map product is detailed, offering customization for amateur radio operators. Each map features two distinct views: one centered on the operator's specific station location and another precisely centered on its _antipode_. Countries are clearly labeled, complemented by a tabular listing of all countries. The map integrates a standard latitude/longitude grid alongside concentric circles that delineate distance increments radiating outward from the operator's QTH. Personalization includes the operator's name, callsign, and location printed directly on the map. This custom mapping service provides a unique visual aid for DXing and propagation analysis, allowing operators to quickly ascertain beam headings and distances from their station. The dual-view presentation, particularly the antipodal centering, offers a practical reference for understanding long-path propagation and identifying potential DX opportunities. The inclusion of distance circles and personalized station data makes it a tailored tool for daily operating and contest planning, distinct from generic world maps.

A solar powered station by IN3AQK using a 10W solar panel charging a 12v Pb sealed battery.

An overview of coax cable often called coaxial feeder or RF cable, used to feed antennas and deliver radio frequency power from one point to another

The _Sci.Electronics FAQ: Repair: RFI/EMI Info_ document, authored by Daniel 9V1ZV, provides a detailed analysis of computer-generated RFI/EMI, focusing on its impact on radio reception. It identifies common RFI sources such as CPU clock rates (e.g., 4.77 MHz to 80 MHz), video card oscillators (e.g., 14.316 MHz), and even keyboard microprocessors, all of which generate square-wave harmonics across HF and L-VHF regions. The resource outlines a systematic procedure for pinpointing RFI origins, including disconnecting peripherals and using a portable AM/SW receiver with a ferrite rod antenna to localize strong interference sources. The document categorizes RFI mitigation into shielding, filtering, and design problems, offering practical solutions for each. It recommends applying conductive sprays like _EMI-LAC_ or _EMV-LACK_ to plastic casings of radios, monitors, and CPUs to create effective Faraday cages, emphasizing proper grounding and avoiding short circuits. For filtering, the guide suggests using line filters, ferrite beads, and toroids on power and data lines, and small value capacitors (e.g., 0.01 uF for serial/parallel, 100 pF for video) to shunt RFI to ground. It also discusses the use of bandpass, high-pass, low-pass, and notch filters on the receiver front-end or antenna feed to combat specific in-band noise.

An air-wound balun made with coaxial cable can not become saturated because no powder iron or ferrite core is present. In this article author explains and compare coax baluns to ferrite baluns with comparison tables and detailed pictures