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Opting for a visually appealing inverted L configuration, G4WIF anchors the End Fed Half Wave antenna to an old clothes line pole, seeking cost-effectiveness in their endeavor. Despite initial misconceptions about transformer components, a £7.95 investment in a T240-43 toroid and DIY mounting container resolves the issue. Reflecting on commercial alternatives, G4WIF's homemade solution proves both economical and sufficient for their amateur radio needs.

An Excel sheet calculator for the T2FD wire antenna. The sheet has been proved to work either on LibreOffice and Apple Numbers. Just input the resonating frequency to get the proper size and dimensions.

Presents a detailed construction guide for a 9 dB, 70cm collinear antenna, utilizing readily available _RG58/U_ coaxial cable and PVC pipe for housing. The resource outlines the critical calculations for ½ wavelength sections at 444 MHz, incorporating the coaxial cable's velocity factor of 0.66, which yields a section length of 223 millimeters. It specifies the preparation and soldering of eight such half-wavelength sections, each cut to 231mm to allow for trimming, forming the core of the array. Further instructions detail the integration of a ¼ wave element (169mm #16 solid wire) at the top and a ¼ wave aluminum tube (160mm, 5/16 inch) at the bottom, crimped to the feed point's braid. The guide also addresses RF common mode current suppression by suggesting the use of _FT50-43_ toroids on the feedline. Final assembly steps cover mounting the antenna within ¾" PVC pipe using a wooden dowel, waterproofing connections, and initial SWR checks. The article also discusses scaling the design for different element counts and other VHF/UHF bands.

Coil64 (Coil32) is a versatile tool for calculating single-layer inductance coils used in various electronics, such as matching circuits and amplifiers. The online calculator enables users to estimate the number of turns, winding dimensions, and select the appropriate wire type for home-brewed RF inductors. It employs Bob Weaver's equation, factoring in wire corrections, and allows for the calculation of Q-factor and self-capacitance. Coil64 is compatible across multiple platforms, including Windows, Linux, Mac-OS, and Android.

This web page is part of a self-help program for licensed amateur radio operators and radio pirates.

There are quite a few recipes for building a suitable transformer for an end fed half wave antenna (EFHW), but I was never sure I really understood the main principles. So, I wound a bunch of transformers, made measurements on them using my NanoVNA, learned how to get what I really wanted out of the VNA measurements, and in the process discovered how to build better transformers and be able to predict what they will do

This article presents the C-Pole antenna project, a compact, ground-independent vertical antenna designed for amateur radio operators. It features a folded half-wave dipole configuration that eliminates the need for radials, making it suitable for various locations, especially in deed-restricted areas. The C-Pole offers efficient performance with a 2:1 SWR bandwidth of approximately 3%, and it can be easily constructed using common materials. Additionally, the article discusses practical aspects such as feed-point impedance transformation and balun design to optimize functionality and minimize losses.

A medium power End Fed Half Wave Antenna coupler, specifically tuned to the QRP frequency of 7030 kHz. Constructed from coil stock and capacitors, it achieves an impedance ratio of 64:1. The coupler has proven effective for power ranges from 2 to 100 Watts on the 40m band.

Constructed in May 2008, this innovative 4m tall electrically full-size halfwave vertical dipole, tunable to multiple bands, offers HF coverage despite its space-saving design. Inspired by cost-effective DIY alternatives, the antenna design departs from conventional center-fed approaches, utilizing asymmetrical dimensions. Despite resonance challenges, the antenna's performance remains viable, boasting broad bandwidth and adaptability, as demonstrated through SWR measurements and EZNEC predictions.

This document details the construction of a multi-band end-fed antenna, suitable for situations with limited space for larger antennas. The design utilizes a 1:49 to 1:60 impedance transformer to match a half-wave wire antenna fed at one end. Compared to a traditional dipole, this antenna resembles a highly unbalanced Windom antenna with one very long leg and a virtual short leg. The design eliminates the need for radials but relies on the coax cable shield for grounding. The document recommends using at least 10 meters of coax and installing a common mode filter at the entry point to the shack for improved performance.

Modification to an old cellular phone base station modules, with a fairly reduced output power (10 watts or so), the stock power amplifier modules will cover the 2.3 GHz and 2.4 GHz amateur radio bands.

The TCARES membership provides communications assistance with fires, floods, search & rescue, and health & welfare message assistance to the Red Cross, without pay, using their own equipment, usually in twelve hour shifts.

This project explores the construction and performance of an Alford Loop antenna as an alternative to a round loop. The Alford Loop, symmetrically fed at opposite corners, behaves like a small loop despite its larger size. Built using PVC pipes and secured with tire wraps, the antenna integrates an LZ1AQ active amplifier for optimal performance. With deep nulls in its horizontal radiation pattern and improved resonance characteristics, this design has significantly outperformed previous active antennas in reception quality.

The GAWANT Antenna, or Shinagawa Antenna is an half-wave vertical end-fed in a FT817-friendly package

The Raspberry PI 3+4 has proven itself as an amateur radio computer. Both at home as the main computer in the shack but also on the road. It is small, inexpensive and incredibly versatile. The operating system and the most important programs are available for free.

Amateur radio enthusiast Jean-Paul Suijs discusses combating manmade noise (QRM) in radio signals using AI. Detailing experiments with phase-shifting techniques and the self-learning nature of AI, he explores AI-based audio processing apps for real-time noise cancellation during radio contests, demonstrating results on both medium wave and shortwave bands.

Intrigued by a German OM positive experience with a 20m delta loop, the author replicated the design, noting its favorable 50-ohm impedance compared to their 40m version. Testing against a vertical EFHW, the delta loop excelled within EU but lagged at longer distances. Despite needing more testing, the user leaned towards the EFHW for its overall performance and practicality.

Hello, I'm glad that you stopped by. In this site you will find some information about myself and much more interresting Ham Radio stuff.

The author explores a portable version of the half-square antenna, typically a single-band structure. Using a 9:1 unun for versatility, they describe construction with speaker wire, deployment using collapsible poles, and field tests, achieving successful contacts on multiple bands. The article suggests efficient matching methods and concludes with the antenna's integration into the author's portable options.

The article details the C-Pole antenna project, emphasizing its portability and ease of setup for amateur radio operators. Key features include its compact design as a vertical half-wave dipole that requires no radials, making it functional at various locations. The antenna employs capacitive loading to reduce physical length while maintaining efficiency. It includes practical advice on resonance tuning, impedance matching, and construction materials, along with a calculator for determining dimensions based on desired frequencies. Overall, it presents a user-friendly solution for portable ham radio communication.

HF contesting is a rising aspect of amateur radio that can be enjoyed (at any level) throughout the year. There are HF and LF contests almost every weekend and on some weekday evenings. Learn how to take part in HF contests.

Controlling a rotator via computer can be costly, but a budget-friendly solution exists using an Arduino Nano and free software by Anthony K3NG. This setup allows for easy and enhanced rotator control, including screen and network management. Though initial software setup can be complex, pre-configured versions are available. Building and customizing the hardware interface is required, with comprehensive support provided by K3NG's resources.

The 1/4 wavelength vertical antenna project, initially designed for 20 meters, has evolved into a versatile portable solution covering 10 through 60 meters. K0BXB details its construction, emphasizing a bottom-loaded design with a tapped loading coil and four 10-foot counterpoise wires. The author shares personal experiences and field results, including **18 QSOs** during a park activation on 17m and 30m with 10 watts, and a **2,435-mile** contact with a contest station in Bonaire on 20m using 5 watts. Comparisons are drawn to commercial offerings like the _Wolf River Coils TIA_ and _QRPGuys Triband Vertical_, highlighting the DIY antenna's small footprint, light weight, and ease of tuning for POTA activations. The resource includes insights into using test equipment such as the _NanoVNA_ for SWR optimization and discusses various radiator lengths, from 17-foot wire to a 102-inch whip, demonstrating adaptability for different portable setups. Construction tips cover coil winding, tap placement, and connecting feedlines and radials using common components.

Constructing a 5-element quad antenna, the author aimed for low cost and simplicity, resulting in an effective design with 11 dBi gain and SWR of 2:1 or better across the 2-meter band. Using wood and dowels, the antenna costs under $8 and takes less than two hours to build with basic tools. The model predicts excellent performance, confirmed by ARRL Lab measurements. Practical field results demonstrate improved communication, even in simplex mode.

Documents the design and construction of a **four-band Moxon beam** antenna, covering 20, 15, 10, and 6 meters. Author W7JMP shares his journey from initial research and computer modeling using 4NEC2 to the final on-air testing and optimization. The project aimed for gain over a dipole on 20 meters, with a budget under $500, including the antenna rotor. The design incorporates fiberglass spreaders and a single feedpoint, avoiding complex relay switching. The article details the selection of materials, assembly techniques, and the critical tuning process. W7JMP describes fabricating the hub, mounting spreaders, and attaching elements made from stripped THTN wire. A notable innovation is the use of a half-wave tuning stub with a loading coil for in-situ adjustment of the 20-meter reflector, optimized via remote S-meter readings using a webcam and smartphone. This method allowed for fine-tuning the **front-to-back ratio** without lowering the antenna. Initial testing revealed a dipole-like pattern, which was significantly improved after tuning, resulting in reported 2 to 4 S-unit front-to-back ratios and enhanced signal strength for DX contacts on multiple bands, including sporadic E on 10 and 6 meters.

This article provides an in-depth review of the Ciro Mazzoni Baby Loop Ham Radio Antenna. The author, a ham radio operator, compares this magnetic loop antenna with his usual End Fed Half Wave antenna, discussing the performance and installation considerations. The post explains the concept of loop antennas, resonating frequencies, and the benefits of using a small loop antenna with a capacitor for optimal operation. If you are looking for information on magnetic loop antennas and their effectiveness in restricted spaces, this review offers valuable insights and practical experiences for ham radio operators.

This article explores the conventional wisdom about antenna height in amateur radio operations, challenging the common belief that "higher is always better." Through practical examples and computer modeling, it examines how low-height antennas like Beverage antennas, VP2E, and End-Fed Half Wave (EFHW) configurations can perform effectively in various scenarios. The analysis includes radiation patterns and efficiency considerations for antennas at different heights, particularly focusing on portable operations. The article demonstrates that while height affects antenna performance, lower installations can still provide practical and efficient solutions for specific applications, especially in portable and QRP operations.

Addresses the common challenge of constructing effective dual-band antennas for VHF/UHF operations, specifically detailing a J-pole design. It covers the theoretical underpinnings, including calculations for quarter-wavelength radiator and stub sections, accounting for velocity factor and design frequency. The resource provides practical construction guidance using readily available materials like TV twin lead and coaxial cable, culminating in an antenna with a total length of approximately 52 inches. Performance metrics are presented, showing a measured SWR of 1.7:1 or better across most of the 2-meter band and less than 2:1 across the 70-cm band. These SWR measurements, referenced to 50-ohm impedance, were taken at the transmitter end of the feed line. The article also touches upon the necessity of a balun for proper impedance matching between the balanced J-pole and unbalanced coaxial feed line, suggesting a split-core cylindrical ferrite for this purpose.

Andrew Georgakopoulos, SV1DKD, modeled the End-Fed Half Wave (EFHW) antenna using MMANA-GAL software. He evaluated the EFHW-8010-2K from Myantennas.com for field operations, comparing it to random wires, OCFD, and dipole antennas. His results showed similar performance to OCFD, confirming EFHW's practical feeding advantage but with potential high-voltage risks at the feed point

The yearly, black, up to 1750, and monthly red, from 1750 up to now, sunspot numbers provided by the Royal Observatory of Belgium SILSO

A homebrew spectrum analyzer, the Specan, provides a crucial measurement capability often missing from the typical amateur radio shack, allowing for detailed analysis of RF signals up to 70 MHz. This double-conversion superheterodyne receiver design incorporates 112 MHz and 12 MHz intermediate frequencies, utilizing an _Si570_ as the local oscillator for fine tuning down to 1 Hz steps. It offers two resolution bandwidths: 300 KHz for broad spectrum sweeps and 1 KHz for precise close-in distortion measurements, achieving an 80 dB spur-free dynamic range at 1 KHz resolution. The project, a reboot of the classic _W7ZOI/K7TAU_ design from November 1998 QST, integrates an _Arduino_ microcontroller for controlling the Si570, managing a front-panel LCD, and communicating with a PC for spectrum plotting. This approach significantly reduces cost compared to commercial units, making advanced RF diagnostics accessible to homebrewers. The Specan can measure carrier suppression, VFO cleanliness, antenna VSWR, transmitter harmonics, and filter passband shapes, providing insights beyond what an oscilloscope or frequency counter can offer. Construction emphasizes modularity and careful shielding, with each stage built and tested individually on unetched copper clad board. The design includes detailed instructions for integrating the Arduino, building the Si570 oscillator, and aligning the various modules, often using the Specan itself for calibration. It requires a well-regulated linear power supply and can be built with common tools and readily available components, making it a practical and rewarding endeavor for those looking to enhance their RF test bench.

The latest version of the K1FM-Loop is electrically similar to the previous one, but it is designed around off-the-shelf parts or, more generically, items you can readily order online. This antenna relies heavily on 3D printing.

The WSSM Emergency Communications Team serves the Cumberland County Emergency Management Agency (CCEMA), and the community in general, by providing emergency communications assistance, conducting programs and training, promoting radio knowledge, fraternalism, and individual operating efficiency, and to conduct activities as to advance the general interest and welfare of Amateur Radio as a viable and efficient means of communications support.

The Slim Jim VHF antenna, originally designed by G2BCX, is a folded half-wave dipole fed by a quarter-wave matching section. This version, built from a recycled professional aluminum dipole, demonstrates that various materials—such as copper, brass, or twin-lead—can be used. The article details the antenna’s construction, required materials, and tuning process, emphasizing mechanical stability and ease of assembly. With proper adjustment of the feed point, it provides excellent SWR across the band. Its durability and simplicity make it a practical and efficient VHF antenna solution.

Notes for new hams using the Baofeng UV-5R3, Basic Ham Procedures, open repeaters, Local Ham Nets.

How to use a little known J-antenna characteristic to reduce a conventional 14 foot antenna to 7 feet. Perfect 50 Ohm match, same gain, no radials.

The exchange of QSL cards by radio amateurs is a practice that is almost as old as radio itself. History of IARU QSL Bureau, evolution of the system

This page provides guidance on designing an End-Fed Half-Wave (EFHW) or Random-Length antenna for amateur HF bands, such as 80 or 40 meters. The content explains how to optimize the antenna for multi-band use and match it to a 50-ohm system using an unun. Hams can generate radiation patterns, VSWR charts, and antenna current diagrams for their customized antenna designs. Understanding how antenna dimensions affect performance is essential for successful field operations. The page caters to ham radio operators looking to build efficient and effective HF antennas for their stations.

The ICOM IC-705, a popular QRP transceiver for portable operations, often presents unique challenges for field deployment. This resource details practical solutions for common portable setup issues, particularly for _Parks on the Air_ (POTA) activations. It describes a custom bracket for connecting antennas to the IC-705 through a backpack's antenna flap, utilizing a BNC female-to-female chassis mount connector to mitigate cable tangles. The author shares experiences with a DIY magnetic loop antenna, noting its ease of tuning with the IC-705 and successful CW contacts on 40 and 20 meters over distances exceeding **1000 miles**. Another modification presented is a strain relief solution for the microphone cord, replacing the standard spring clip with an easier-to-attach method. The page also mentions using a _Wolf River Parks antenna_ for POTA activations and references the QRPGuys DS-1 antenna as another portable option. Firmware updates and integration with an LDG Z11-Pro II auto-tuner are also discussed.

This page delves into the debate surrounding the End-Fed Half-Wave (EFHW) antenna, exploring whether it is truly a multiband antenna without the need for a tuner. The author investigates the claims and criticisms surrounding these popular antennas, discussing their resonance on various bands and their efficiency for DXCC achievements. The content is valuable for hams interested in understanding the capabilities of EFHW antennas and their performance across different HF bands, with a focus on practical usage and real-world results.

Wavelog, a web-based amateur radio logbook application, launched in February 2024, represents a significant fork from the established Cloudlog platform, developed by a core team including DF2ET and DJ7NT. This open-source project focuses on delivering advancements in both stability and functionality, specifically tailored for the amateur radio community. The application allows users to manage their radio logs from diverse environments, including professional servers, standard web hosting, or even compact _Raspberry Pi_ setups. The platform distinguishes itself through its emphasis on simplicity, robust features, and versatile accessibility, enabling operators to log contacts from virtually any location. It supports various operating modes and data formats, providing a flexible solution for tracking QSOs and managing station activities. The project's development is driven by the collaborative spirit of the amateur radio community, prioritizing utility and user experience over commercial objectives. Key features include comprehensive logging capabilities, support for multiple bands and modes, and integration with common amateur radio data standards, ensuring broad utility for DXers and contesters.

This article addresses the issue of unwanted RF in amateur radio setups and introduces a practical method to measure common-mode currents (CMC) using a homebuilt RF meter. The meter, constructed with readily available materials, measures unwanted RF on the coaxial cable shield by inductively coupling to the shield using a split-bead ferrite. The article provides detailed instructions on building the meter, interpreting measurements, and using ferrite chokes to mitigate RF interference. Emphasis is placed on the importance of verifying CMC levels and installing chokes to improve equipment performance.

A C-Pole Antenna for QRPxpeditions describes a DIY C-Pole antenna designed for QRP (low-power) expeditions, inspired by KF2YN’s ground-independent vertical model. After adjustments, it achieved a 1:1 SWR at 14.060 MHz, rising to 2.5:1 at 14.35 MHz. A choke balun, comprising 15 turns of RG8X around a 4” can, was essential for optimal performance. Compact and self-supporting, the antenna enables reliable communication with minimal setup. Contacts included stations across the U.S., and even a 4,600-mile connection to Spain using only 5 watts.

This article provides an overview of setup Direwolf and QtTermTCP for HF packet radio operations. It covers important tasks such as setting up a Direwolf TNC, connecting with stations, and engaging in packet-based chat (K2K). It also looks at how to use nodes as relays and access basic BBS services. The paper also includes HF packet network etiquette recommendations and a description of how to handle common packet transmission issues, making it a useful resource for amateur radio enthusiasts.

A quick guide to install direwolf, bpq and jnos on a Raspberry Pi. By following the instructions in the examples listed on this page, you should get it to work.

A half wave wire that is tuned for resonance on 80m will NOT be resonant on 40m despite a precise harmonic relationship between the two bands. The End Effect is caused by a capacitive coupling between an unterminated wire end and the ground.

The 8m ISM band, a unique frequency range between 10m and 6m, holds potential for amateur radio enthusiasts, yet it remains largely unallocated. This spectrum offers fertile ground for research and self-training. The author's experience with low-power transmissions and WSPR testing highlights the band's capabilities and the need for a narrow, speech-free amateur allocation to encourage experimentation. Discover the world of 8m ISM radio exploration and its future possibilities.

This article published on QEX details measurements of tree conductivity and permittivity at HF frequencies, addressing a long-debated topic in amateur radio. N6LF conducted experimental impedance measurements on Douglas fir and maple trees using a vector network analyzer with rings of nails inserted into tree trunks. Results showed that tree conductivity increases with frequency while relative permittivity decreases, similar to soil characteristics. Measured conductivity ranged from 0.06 to 0.4 S/m at 10 MHz, aligning with values used in previous research. These findings validate that NEC modeling can reliably estimate trees' substantial impact on HF antenna performance.

This page discusses the CLEFHW (Coil Loaded End-Fed Half-Wave) antenna, a portable variation of the popular EFHW design for ham radio operators. The article explains how the CLEFHW allows for backpack portable operation without the need for trees or poles, making it ideal for POTA activations and rapid deployment scenarios. The author details the design, optimization for 20m band, and compares efficiency to full-length wire antennas. Suitable for hams interested in portable antenna solutions and quick setup options for amateur radio activities.

PH0NO conducted field tests comparing a mobile antenna (DX-UHV) to an end-fed half-wave wire. Results on 20m showed the end-fed wire outperforming the mobile antenna, with a significant difference in signal strength. On 40m, the end-fed wire surpassed the mobile antenna in spots and reach. While the mobile antenna is more practical, the end-fed wire offers superior performance. Further testing is planned.