Search results

This page by Keith Greiner describes a magnetic loop antenna project, providing step-by-step instructions to create two versions of a system with one large loop and one small loop. It includes details on how to construct the loops using different materials, along with the necessary equipment like antenna analyzers, tuners, and software. The page is divided into five sections covering project discussion, design summary, an improved small loop, construction steps, and radiation pattern analysis. Aimed at hams interested in building their own magnetic loop antennas, the page offers practical guidance and insights into impedance matching for improved performance.

The document details the construction and performance of a rotatable flag antenna designed for a small lot. The 7x14 feet flag, built with fiberglass poles and an aluminum hub, shows improved reception compared to the author's previous transmit antenna. Key components include a conventional transformer for impedance matching and a variable resistance termination system to optimize performance. Despite challenges like nearby objects affecting signal patterns, the antenna consistently provides better signal-to-noise ratios, making it a valuable addition for low-band listening in suburban areas.

This project focuses on testing and comparing various antennas for receiving ADS-B (Automatic Dependent Surveillance-Broadcast) signals, utilizing software tools like RTL1090 and Virtual Radar with an RTL-SDR dongle. The goal is to evaluate the reception range ("ReceiverRange") and performance of different antenna types when tracking aircraft signals, particularly around the Amersfoort area. The project includes a comprehensive photo album documenting the antenna designs and setup processes, serving as a valuable resource for enthusiasts building ADS-B reception systems

The article details the design and construction of a four-band Moxon beam by a radio amateur. The beam, mounted atop a rooftop tower, aimed for gain over a dipole on 20 meters, cost under $500, and included additional bands. The design features fiberglass spreaders, four bands (20/15/10/6 meters), and a single feedpoint. The construction involved computer modeling, NEC source code, and specific dimensions. The article outlines the assembly, materials, and tuning process, including in-situ adjustments for optimal performance. Despite initial challenges, the beam improved signal strength and facilitated contacts on multiple bands, marking it as the best HF antenna the author has owned.

A Magnetic Loop Controller project details the construction and operation of an automatic tuning system for magnetic loop antennas, which are resonant circuits using an oversized inductor and an adjustable capacitor. The system employs a stepper motor to precisely adjust the variable capacitor, maintaining optimal resonance across the HF bands. It integrates with various transceivers, including _Icom_, _Kenwood_, and _Yaesu_ models, by monitoring the VFO frequency and adjusting the loop's tuning accordingly. The project provides comprehensive building instructions, a PowerPoint-style presentation, and the full source code for the controller's firmware, enabling hams to replicate and customize the design. The controller's firmware offers diverse functionality, including automatic frequency tracking, manual tuning, and SWR monitoring, significantly enhancing the operational efficiency of magnetic loop antennas, particularly for QRP and portable operations. The design emphasizes accurate capacitor positioning, crucial for achieving low SWR and maximum radiated power. Comparisons with manual tuning methods highlight the benefits of real-time adjustment, especially when operating across different bands or making frequent QSYs. The project's detailed documentation and available source code facilitate experimentation and modification by advanced builders, allowing for tailored performance characteristics.

This project details the construction of a compact, circularly polarized Quadrifilar Helix Antenna (QHA) designed for 146 MHz operation. The antenna features a 1/2λ1/2λ helical design with a 2.6:1 aspect ratio, providing 4.5 dB gain and a spheroid radiation pattern. It is ground plane independent and compatible with both vertical and horizontal polarizations, making it ideal for terrestrial and space communications. The design includes step-by-step instructions for building the antenna using readily available materials like aluminum rods, PVC pipes, and RG-58 coaxial cable. The antenna's performance has been validated through comparisons with commercial omnidirectional antennas, showing superior results.

This PDF document provides a comprehensive guide on building and using the Moxon Rectangle antenna design for hams. It covers the construction, setup, and tuning of this directional antenna, offering practical advice and tips for amateur radio operators looking to improve their signal reception and transmission capabilities. The guide includes diagrams, measurements, and step-by-step instructions to help hams successfully implement the Moxon Rectangle design for their radio communication needs.

This article details the author's process of designing and building a trap dipole antenna for the 17, 12, and 6-meter amateur radio bands using a Yaesu FT-450 transceiver. The antenna incorporates parallel-tuned circuit traps to enable operation across multiple bands without switching aerials. Key construction details, including coil and capacitor specifications, are discussed, along with the testing results, which include successful long-distance communications on the 50 MHz band. The article highlights the flexibility of home-built antennas and provides insights for amateur radio enthusiasts looking to optimize multi-band performance.

Building an efficient antenna begins with selecting the right aluminum stock. This article provides a comprehensive guide to sourcing aluminum materials for antenna construction. It covers different aluminum grades, their tensile strengths, tempering options, and their suitability for various antenna components. The article also recommends reputable suppliers in the UK, making it a valuable resource for antenna builders seeking durable and high-performance materials.

A DIY cantenna can extend your WiFi range by building a 2.4 GHz high-gain antenna using accessible materials. The design, based on waveguide principles, uses a cylindrical tube to capture WiFi signals and can even connect to access points half a mile away in ideal conditions. While the ideal tube diameter was hard to find, a 4-inch aluminum dryer vent was chosen despite theoretical limitations. The cantenna offers a cost-effective, functional boost for your wireless network.

Learn how to build your own QRPGuys DS-1 40-10m short vertical antenna for ham radio operators. This page provides detailed instructions on constructing this antenna, which covers the 40 to 10-meter bands. Whether you're a beginner looking to get started with antenna building or an experienced ham radio operator looking for a new project, this resource is useful for anyone interested in DIY antennas for portable or QRP operations.

This page provides construction details for a 4-element 10-meter Yagi antenna with 28 Ohm impedance. It includes information on the elements, positions, diagrams, and data related to frequency, gain, front-to-rear ratio, radiation resistance, SWR, and loss. The content is aimed at hams or radio operators interested in building and optimizing Yagi antennas for the 10-meter band.

This page provides detailed information on the 4DX directional wire beam antenna designed by LZ1AQ, LZ1ABC, VK6LW, and DD5LP. It explains how to create this antenna for single or multiple bands using four separate sloping wires. The page includes instructions on achieving directionality, gains, and F/B ratios, as well as generating radiation patterns, VSWR charts, antenna currents diagrams, and Smith charts. It is a valuable resource for hams interested in building and optimizing their own directional wire beam antennas for improved performance and long-distance contacts.

The field strength meter (FSM) is a very useful addition to any HAM toolbox. If you are messing around with antennas, or building PA's, or trying to repair some TX gear, the FSM will come to your rescue when there is doubt about the output level.

This page provides a detailed step-by-step guide on building a 70 cm band repeater antenna for hams. The instructions are clear and easy to follow, making it suitable for both beginners and experienced operators. The antenna design is optimized for the 70 cm band, ensuring efficient communication for local repeater systems. Whether you're looking to improve your repeater setup or just starting out in amateur radio, this guide will help you build a reliable and effective antenna for your station.

The author describes his experience building and using a Beverage antenna for the 40-meter band. Despite encountering some challenges, the antenna offered some improvements in receiving stations compared to a 3-element inverted Vee antenna. The Beverage antenna showed a significant daytime signal-to-noise ratio improvement and received signals better than the Vee antenna. However, the front-to-back ratio was not ideal, and the transmit power seemed to affect the Beverage antenna. Overall, the author concludes that the Beverage antenna might be more suitable for locations with higher noise levels. The total cost of the antenna was around 30 Euros.

Building some proper matching transformer for loop on ground and Beverage antennas

This article details the development of an 80-meter antenna within the confines of a restrictive covenant community. Faced with limited space, the author explores various options before implementing a clever hybrid design: a short 30-foot vertical wire running discreetly down the building's exterior combined with a capacitive top hat installed in the attic. Computer modeling confirmed the superiority of capacitive loading over inductive loading, increasing radiation resistance from 6 to 14 ohms. The perimeter wire top hat, naturally supported by the attic structure, resonates effectively at 3.5 MHz. The system is completed with four buried 60-foot radials installed "after dark" to maintain compliance with community restrictions.

Learn how to easily build a 10-meter vertical antenna, perfect for DX contacts on the amateur radio bands. This flowerpot or T2LT design is portable, efficient, and ideal for ham radio operators looking to improve their DX performance. With just a few basic tools and materials, you can construct this antenna for portable operations or as a home station setup. Discover how to set up the antenna, improve its performance by raising it higher, and start making contacts with stations around the world. Watch a step-by-step guide on YouTube for building and testing this DIY ham radio antenna.

Building a radio repeater enhances communication by extending signal range and overcoming obstacles like mountains or buildings. This guide explains the fundamentals of radio repeaters, their function, and a step-by-step DIY approach. Key steps include conducting a site survey, selecting an optimal installation location, and configuring the system with suitable equipment such as the Retevis RT97 series. Proper placement, antenna setup, and testing ensure effective operation, making this process accessible for enthusiasts aiming to improve communication reliability and range

This document provides comprehensive guidance on modeling and constructing multiband dipole antennas using traps. It addresses common segmentation issues in EZNEC modeling software, recommends optimal segment lengths for trap models, and compares trapped dipoles with paralleled multiband dipoles. While trap dipoles are significantly shorter, they exhibit lower gain and narrower bandwidth. Detailed instructions for building weatherproof coaxial traps include material lists, construction steps, and tuning methods. The guide notes that properly constructed coaxial traps introduce only minimal signal loss (0.6 dB) while offering practical multiband performance in a compact design.

This blog post documents the author's journey building an APRS micromodem for amateur radio applications. Using an open-source design by LY2EN, the author assembled a cost-effective Terminal Node Controller (TNC) with SMD components, an Arduino Nano, and a JDY-31 Bluetooth module. The construction process included PCB fabrication, careful component soldering, microcontroller programming, and Bluetooth configuration. A custom 3D-printed case protected the completed device. Field testing in Romania showed the device functioned with a Baofeng UV-5R radio, though antenna limitations affected performance. The entire project demonstrates an affordable DIY alternative to commercial APRS trackers.

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.

The author describes building a remote switch box to control the direction of two reversible Beverage antennas. The switch uses a buried cable and relays to select the desired antenna direction from the shack. The design is simple and uses common components.

Chavdar Levkov, LZ1AQ, presents an experimental comparison of small wideband magnetic loops, building on his previous work on wideband active small magnetic loop antennas. His research focuses on increasing loop sensitivity by maximizing the short-circuit current, which is directly tied to the "loop factor" M = A/L, where A is the equivalent loop area and L is its inductance. Levkov's methodology involves reducing inductance and increasing area through parallel or coplanar crossed (CC) configurations, comparing these designs against a reference single quad loop of 1 m2 area. Experimental verification included testing three distinct loop types: a simple quad loop, two coplanar crossed (CC) loops, and eight parallel loops, all designed to have a total geometric area of 1 m2. Measurements were conducted at 1.8, 3.5, 7, and 10 MHz using a small transmitter 270 meters away, with a Perseus direct sampling receiver for precise signal level assessment. The results consistently showed that CC loops, particularly Loop 5 (two CC circular loops with 1.44 m2 total area), yielded significantly higher currents, up to 9.1 dB over the reference loop at 3.5 MHz, validating M as a reliable predictor of loop sensitivity. Numerical simulations using MMANA further corroborated the experimental findings, demonstrating an almost perfect correlation between the calculated M factor and the induced loop current for 15 different loop models. Levkov concludes that CC loops offer superior sensitivity for a given loop area, while parallel loops are advantageous for minimizing physical volume. Practical recommendations suggest using loops with an M factor greater than 0.5 uA/pT for quiet rural environments, and he provides a spreadsheet tool, WLoop_calc.xls, to aid in optimizing loop configurations for specific operational needs.

This page provides information about building a Beverage antenna for hams. The article discusses using a 60m wire on the ground to create an effective antenna for amateur radio operators. Learn how to set up and optimize this type of antenna for better reception and communication. This describes a low-noise receiving Beverage antenna setup for low bands, using a N30 cup core transformer for 1:4 impedance matching (likely 50:200 Ohm), RG-58 feedline with heavy common-mode choking, and conduit for wire burial.

Guide to constructing an effective antenna for 50MHz. Inspired by a design from Martin DK7ZB, the article emphasizes the importance of precise measurements and quality materials. With a 2.20m boom and careful assembly, the antenna promises excellent performance, resilience, and cost-effectiveness, making it ideal for six meter band operations.

Operating on the 60m band requires specialized antennas, and the 2 Element HB9CV, also known as the _ZL special_, excels in this domain. With a gain of **7.3 dBi** when phased at a 162-degree shift, it rivals traditional 3-element Yagi antennas, making it a solid option for enhancing 60m operations. The construction process is thoroughly detailed, providing insights into its performance and practical applications. Real-world comparisons demonstrate that the HB9CV antenna outperforms long Beverage antennas by an average of **5.5 dB** in reception, showcasing its effectiveness in various conditions. Insights from Mr. Cebik's analysis further validate its design, confirming its capability to maximize communication on the 60m band.

This page details the construction of an ATU-100 (N7DDC) automatic antenna tuner. It provides a photographic build log from the arrival of parts to the final assembly, including winding the tandem match and connecting the OLED display and optional control buttons. The author discusses modifying the EEPROM for QRP operation by setting the minimum tuning power to 1 Watt. Key components shown include the SWR bridge, relays, and the custom case made from a Macbook Pro cover. The article references external GitHub pages for full information, R0AEK's pages for helpful details, and a video by MW0SAW regarding EEPROM settings for different ATU-100 variants. The build focuses on practical steps and includes tips like modifying RG58 strands for PCB fit and adding capacitors to button connections to prevent RF interference with the CPU. The author plans further testing during SOTA or portable activities.

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

This FAQ covers building and buying transformers for loop-on-ground and Beverage antennas. Building one uses ferrite cores and thin wire. Buying is an option, with the DX Engineering BFS-1 being recommended. These transformers isolate the antenna from the cable to prevent unwanted signal pickup.

This article describes the design and construction of a 4-meter band vertical sleeved dipole antenna, built to complement a newly acquired Yaesu FTDX10 transceiver. The simple yet effective antenna consists of modified coaxial cable housed in weather-resistant plastic conduit, featuring an integrated 8-turn choke coil. Despite common misidentification as an EFHW antenna, this design is actually a sleeved dipole that provides an excellent 50-ohm match across the band, achieving SWR values between 1:1 and 1.1:1. The project demonstrates an economical approach to entering the relatively quiet 4-meter band.

Andrew Roos (ZS6AA) details his practical approach to building a Single Operator Two Radio contest station within suburban constraints. The article explains how he leveraged a Force-12 C-31XR triband beam's unique separate feed arrangement to operate on two bands simultaneously. Using band-pass filters and an antenna switch, he achieved sufficient isolation between bands without requiring multiple towers. The setup includes automatic band selection, audio switching, and computer control. Testing during the 2007 CQ WPX CW contest confirmed the system's effectiveness, demonstrating that competitive SO2R operation is achievable with limited space and budget.

Learn how an experienced ham radio operator rebuilt his trap dipole antenna for 30, 40, and 80 meters after a storm damage. Discover the process of upgrading to a short trap dipole for 40, 80, and 160 meters using double-wound traps made from RG-58 coax. Follow along for construction details and tips on building this unique classi.

This article describes a DIY RF field strength meter project inspired by VK3YE's "The Squeakie" design. The device, built around a 555 timer IC and a 1N4148 diode, converts RF signal strength into audible tones with proportional pitch. The author enhanced the original design by adding volume control, LED indication, and digital readout capabilities using an Arduino Nano and LCD display. The completed project functions as a versatile RF detection tool, suitable for antenna testing and fox hunting, while offering multiple output methods: audio, visual, and digital measurement display.

The W6PQL 23cm Beacon Project describes a **1296 MHz** beacon designed for microwave propagation studies and equipment testing, capable of 30 watts output. It utilizes a PIC 16F628A microcontroller to generate CW and FSK keying for a crystal oscillator, followed by a series of frequency doublers and triplers to reach the target frequency. The final power amplification stage employs a Mitsubishi M57762 module, providing a robust 10-watt RF output. The design emphasizes stability and reliability for continuous operation, with the microcontroller code, written in assembly, provided for customization of the beacon's callsign and message. Originally located in CM97am and aimed at 140 true, the beacon used four 4-foot Yagis stacked vertically for a total ERP of 3kW. The article includes schematics, parts lists, and construction notes to guide builders, along with antenna pattern measurements. Although the beacon itself is no longer in service as of August 2010, the detailed documentation remains a valuable reference for amateur radio operators interested in building similar **microwave** projects or understanding beacon operation.