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In this study, the author builds upon Muncy's research, demonstrating that radio-frequency current on cable shields affects audio systems through the "pin 1 problem" and shield-current-induced noise (SCIN). An enhanced equivalent circuit for ferrite chokes is proposed, addressing dimensional resonance and inductor self-resonance. Field tests confirm that chokes reduce interference across 500 kHz to 1,000 MHz. Guidelines for diagnosing and mitigating EMI from various sources are provided for product development and field installations.

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.

This document outlines various miniature projects undertaken by Mike Markowski to enhance his skills in GNU Radio. Key projects include an FM stereo receiver and an AM radio receiver, featuring advanced functionalities like pilot tone recovery and RDS integration. Additional experiments involve generating Gaussian noise, chirp signals, and Morse code decoding, emphasizing hands-on learning and customization in GNU Radio. The author encourages feedback and shares flow graphs and Python code for each project, aiming to foster community engagement and knowledge sharing.

Learn how to build a simple transmitter called the 'Easy Ten' that can be easily heard at a distance of 10 miles using a random length wire antenna thrown into a tree. This article focuses on working with frequencies in the 3.5 and 7 MHz range without the need for complex setups like coax lines or baluns. The author shares their experience of making contacts across the Pacific Ocean and the United States using just one watt of output power and simple antennas. Discover how to optimize signal output using a homemade level meter made from a DC microameter and a germanium diode.

A 13-foot total radiating element length is achieved by combining a Buddipole Long Telescopic Whip with 4 feet of modified tripod tubes, forming a low-profile, multiband antenna for **POTA** operations. The resource details the transformation of an Amazon Basics Aluminum Light Photography Tripod Stand, focusing on electrically isolating the top two radiating sections from the bottom support. John, VA3KOT, outlines component sourcing, including the 9-foot 4-inch fully extended whip, and emphasizes using adhesive copper tape for reliable electrical contact and conductive grease to prevent oxidation at tube connections. The construction process, while not requiring specialized tools, highlights careful assembly to ensure proper electrical conductivity and mechanical stability. The author's experience with this setup suggests its effectiveness for portable activations, offering a discreet profile compared to larger antenna systems. The design prioritizes ease of deployment and transport, making it a practical solution for operators seeking a compact yet versatile antenna for field use.

Demonstrates the construction of an **ATU-100 (N7DDC)** automatic antenna tuner, detailing the assembly process from component arrival to final enclosure. The resource covers winding the tandem match transformer, connecting the OLED display, and integrating optional control buttons. Specific attention is given to modifying the EEPROM settings for **QRP operation**, reducing the minimum tuning power to 1 Watt, and addressing potential RF interference with CPU by adding capacitors to button connections. The build log includes practical tips such as adapting RG58 coaxial cable strands for PCB mounting and utilizing a repurposed Macbook Pro cover for the custom enclosure. The author references external GitHub pages for comprehensive information, R0AEK's resources for additional details, and a video by MW0SAW for EEPROM configuration across different ATU-100 variants. Future plans involve field testing the completed tuner during SOTA or other portable activations.

Author proves a swift and enjoyable method for scanning and exhibiting cherished QSL cards in the shack. Scanning each QSL card and displaying them. A Modern Solution for Scanning and Showcasing Your Favorite QSL Cards

Recently, at the Ballarat Hamfest, the author acquired an old Marine transceiver for just $10, charmed by its sturdy construction and waterproofing. Made by Findlay Communications in Sydney, this crystal-controlled transceiver had been dormant but was reinvigorated with minor fixes. A manual was sourced, and further repairs were made, including an ingenious crystal oscillator replacement using an Si5351a controlled by an Arduino. The refurbished radio, complete with a fresh coat of paint and added customizations, is now operational for 160m AM and 30m SSB. A successful and cost-effective restoration.

The _DX EXPLORER_ blog serves as a personal chronicle of amateur radio experiences, particularly emphasizing homebrew projects and DIY radio equipment. It provides insights into constructing various transceivers and receivers, such as the Minimalist CW Transmitter and the Sputnik Regenerative Receiver, offering practical guidance for those new to the hobby. The content often details the assembly and operation of low-cost kits like the $3 Pixie Transceiver, demonstrating accessible entry points into radio construction. Beyond building, the site also features reviews of commercial gear, including the Tidradio TD-H8 Radio, providing an operator's perspective on performance and utility. The author, YO6DXE, shares a learning journey, aiming to inspire fellow enthusiasts to engage with the technical aspects of amateur radio. This resource covers a range of topics from basic circuit explanations to practical operating tips, fostering a deeper understanding of radio principles. The blog's focus on personal experimentation and project documentation makes it a relevant resource for hams interested in hands-on learning.

Twigger is a very lightweight, free ham radio logger designed for Windows, offering seamless integration with transceivers via _TCI_ or OmniRig. This software stores all logged contacts in a SQLite database, with the flexibility to export daily ADIF files for import into a main logger or to send real-time QSO data via UDP in N1MM XML format. It also supports direct, real-time uploads to popular online logbooks like Clublog and QRZ.com, streamlining the logging process for active operators. The application has seen continuous development, with version 1.1.34 fixing an ADIF log importer bug and earlier versions adding crucial features like WSJT-X/JTDX UDP support. Author OE3IDE, Ernst, has incorporated user feedback, including ideas and testing from MW0LGE, to refine the software. Key enhancements include the transition to SQLite for data storage in version 1.1.32, allowing for easy import of previous Twigger ADIFs upon initial startup. The logger also features integrated DX cluster support, enabling users to send spots directly and query QRZ.com for callsign information, which is then cached to reduce redundant queries. The software's compact design and essential logging capabilities make it a practical tool for casual logging or as a secondary logger during contests, with the ability to handle **25 downloads** for version 1.1.34.

Learn how VE6LK built a comprehensive radio go-kit for emergency communication purposes. The kit includes Yaesu FT-8800, Yaesu FT-857, LDG FT-Meter, Powerwerx SS-30 power supply, SignaLink USB interface, and more. The author shares details on the equipment, organization, and practical tips for setting up the kit. Discover how to stay prepared for public service events, disaster responses, and general ham radio activities with a well-equipped go-kit.

Examining the demographic shifts within amateur radio, particularly concerning **radiosport** participation, this resource analyzes survey data from the National Contest Journal (NCJ) and two regional ARRL surveys. It focuses on the relationship between age and engagement in contesting, presenting findings that suggest older amateur radio operators tend to participate in more contests annually. The author, a spatial demographer, details the methodology, including data consolidation, georeferencing, and statistical analysis performed in collaboration with Dr. Scott Wright K0MD, covering ARRL November Sweepstakes participants from 2000 to 2020. The analysis also addresses the limitations inherent in using voluntary response samples rather than random samples, which may influence the generalizability of the results. Furthermore, the resource investigates the preferred sources of contest information among different age groups, noting that older contesters frequently rely on traditional publications like the NCJ, while younger participants show a preference for online platforms. This demographic review provides insights into the evolving landscape of **amateur radio contesting** and the generational differences in information consumption.

This article discusses the evolution of portable amateur radio operations, focusing on optimizing backpack-carried equipment for outdoor use. The author shares his journey from using wheeled carts to developing an innovative backpack-mounted antenna system, emphasizing the transition from high-power (QRO) to low-power (QRP) operations to reduce weight. The piece details practical solutions for antenna mounting, equipment selection, and portable operations in challenging terrain, particularly along Ontario's Niagara Escarpment. The author's approach prioritizes mobility and functionality while maintaining effective radio communications in remote locations.

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.

This document serves as a thorough guide to amateur radio nets throughout Australia and includes some international (DX) nets. It outlines key information like frequencies, schedules, and the people responsible for managing these nets. Among the nets covered are Ron's 10 A.M. net, the Australian Travellers Net, and several others, each operating on different bands and regions. Additionally, it offers technical details about repeaters, such as frequency, offset, and CTCSS tones where applicable. Any updates are clearly marked, and further details are included for linked repeater systems and network connections.

Learn how to create a USB Keyer for PowerSDR to enhance your CW experience. This article provides a step-by-step guide using affordable materials like a USB to TTL Module (FT232RTL) and a Keyer iambic. The tutorial includes a detailed wiring diagram and instructions for configuring the Keyer in the PowerSDR menu. The author also shares a helpful video demonstration to ensure smooth operation. Whether you're a seasoned ham operator or new to CW, this DIY project can improve your radio setup. Follow these instructions to build your USB Keyer and elevate your PowerSDR experience.

The article discusses the evolution of antenna designs, specifically focusing on the upgrade from the W7IUV rotatable Flag to the Waller Flag. Author Pierluigi Mansutti IV3PRK shares insights on modeling these antennas using EZNEC software, detailing their performance in noisy environments. The W7IUV Flag proved effective for receiving signals, while the Waller Flag, developed by NX4D and N4IS, offers improved front-to-back ratios but requires careful consideration of signal levels and noise management. The article emphasizes practical modeling results and interactions between different antenna setups.

This blog post from KA7OEI covers the author's initial exploration into the world of Arduino, a popular open-source electronics platform. The post likely discusses the author's experiences, challenges, and successes with Arduino projects, particularly in relation to amateur radio or other technical hobbies. It may provide insights, tips, or inspiration for hams interested in incorporating Arduino into their own projects. The content is likely informative, personal, and geared towards amateur radio operators or electronics enthusiasts.

This page discusses the use of the new Version 4 RTL-SDR dongle for simple QRSS reception. The author shares their experience with connecting the dongle to a PA0RDT miniwhip antenna and using RTLSDRlop QRSS software. They encountered issues with Linux but found a solution with a new driver. The page also provides information on coupling multiple dongles to one antenna and adding selectivity with a divider-filter box. Hams interested in experimenting with RTL-SDR technology, antenna setups, and software for QRSS reception will find this content useful.

Repairing a non-functional Yaesu FT857 by identifying and replacing two damaged components crucial for powering the device. Using discrete components, author constructed replacements for the DAN222 and RT1N241 ICs, successfully restoring the rig's functionality. This DIY approach not only fixed the issue but also provided a satisfying and cost-effective solution

This post discusses the Norcal 2N2/XX CW transceiver kit and provides suggestions for minor mods and parts substitutions. The author shares their experience assembling the kit and highlights the simplicity and joy of operating a QRP CW transceiver. The post also includes images and a list of recommended modifications towards the end. If you own or are interested in acquiring a Norcal 2N2/XX kit, this post offers valuable insights and recommendations to enhance your experience as a ham radio operator.

This article from the July 1976 issue of Radio REF discusses the trend of large antennas for ham radio operators on the low bands. It specifically focuses on a Yagi 2 element antenna for the 80m band, detailing its construction and functionality. The author explains how the antenna can be switched between directing signals towards the West or East using a switch at the station. The article also provides technical details on the lengths of the director and reflector elements, and how they impact the antenna's performance. A useful resource for hams looking to build or understand Yagi antennas for the 80m band.

This article discusses the design and implementation of a 2-element wire beam antenna for the 20 meter band, suitable for field day operations with 4 Switchable Directions. The antenna is configured with sloped wires in an inverted V shape, with a specific design to achieve directional properties. The author tested the antenna design using MMANA and NEC2 software, based on a solution published in QST. Detailed diagrams and instructions are provided for constructing the antenna on top of a 12 meter mast, with specific wire lengths and positioning to ensure optimal performance. This resource is valuable for hams looking to build a directional antenna for the 20m band and improve their field day setup.

This page discusses the potential risks and safety concerns related to antenna installations for ham radio operators. It emphasizes the importance of following electrical codes and regulations to prevent property damage, injuries, or even loss of life. The author shares personal experiences and advises against using trees for antenna support near power lines. The content serves as a cautionary resource for hams planning antenna setups to ensure safety and compliance with regulations.

This article explores the powerful features of AutoEZ as an Excel application working with EZNEC antenna modeling software. The article demonstrates how variables, equations, and formulas enable versatile antenna design and automatic optimization. Through practical examples including dipoles, inverted vees, delta loops, and monopoles, the author shows techniques for achieving resonance, implementing transmission line resonators for broadbanding, and optimizing antennas across frequency ranges. The step-by-step demonstrations cover unit conversion, coordinate calculations, segmentation considerations, and SWR optimization. This practical guide illustrates how AutoEZ extends EZNEC's capabilities, making complex antenna modeling more efficient and accessible.

This page discusses the construction and design of a shortened 2-element Yagi antenna for the 40-meter band, focusing on the driven element. The author shares insights on adding hats to the coil to reduce losses and improve performance. The article also mentions the use of EZNEC modeling software and an AIM4170 analyzer for tuning. Amateur radio operators interested in such antenna design and optimization for the 40-meter band can find useful information and practical tips on this page.

Demonstrates practical **rules of thumb** for selecting and utilizing ferrites and coils in amateur radio projects, particularly for RF applications up to 30 MHz. It addresses common challenges like determining appropriate ferrite grades and estimating L/C values without precise specifications. The resource details the author's experience with readily available grey ferrites, noting their suitability for HF work, and provides guidance on constructing **baluns** and RF chokes, balancing inductance for lower frequencies against inter-wire capacitance for higher frequencies. It also outlines a method for estimating power handling based on ferrite weight, suggesting a 1-gram ferrite can manage over 2 Watts, and offers a technique for evaluating unknown ferrites by winding 10 turns and measuring resonance with a 1 nF capacitor. This approach emphasizes a hands-on, iterative method for balun winding and adjustment, allowing operators to quickly approximate component values. The article compares the characteristics of ferrite-cored coils with air-cored coils, highlighting the reduced pickup and radiation of ferrite designs. It refines the air-coil estimation method for frequencies between 2.5 MHz and 10 MHz and provides a scaling factor for frequencies outside this range, aiming to get operators into the correct general area for their designs. The author's standardized ferrite choice (RND Components 165-00182) is presented as a practical example for reproducible projects.

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 article demonstrates how to convert an existing tower into a dual-band vertical antenna for 80- and 160-meter DX operation. Using EZNEC modeling and practical design principles, the authors achieved a low-profile, efficient setup with a single coax feed line, no moving parts, and optimal radiation patterns. The system integrates an 80-meter vertical wire and a 160-meter shunt-fed gamma match for simultaneous operation. Detailed construction insights, including feed system and capacitor configurations, offer a reliable, full-legal-power solution.

In this project by building a W2IMU feed horn, the author successfully optimized their 10GHz Small Dish EME project. To position and solder the components together, they used a jig and a conical section made of copper sheet. Stability was ensured by fitting the XLNA to the WG switch. The WG components were shod into a waterproof plastic container, and the feed horn and WG were surrounded by a collar and skirt that were 3D printed. With an average Moon noise of 0.5dB, the Sun and Moon noise readings were better than their previous configuration.

This page details the construction project of the 'Stone', a QRP double conversion superhet SSB transceiver for the 40m band. The project is based on a kit from Tim Walford, G3PCJ, and includes step-by-step instructions for building and testing each stage. The author has added enhancements such as a three digit frequency counter and an automatic gain control. The content is aimed at hams interested in DIY transceiver construction and includes technical details of the build process.

This page contains detailed notes on repairing and aligning the Kenwood TS-440S HF radio. The author shares their experience repairing several TS-440S radios, highlighting common issues and repair techniques. The page also discusses parts availability, modifications, and the radio's performance for digital modes like FT8 and JT65. Aimed at ham radio operators interested in repairing and maintaining vintage HF radios, this page provides valuable insights and tips for working on the Kenwood TS-440S.

This page delves into the early history of radio and television, exploring the fascinating personalities and inventions that shaped the industry between 1870 and 1929. The author reflects on the pioneering work of figures like Thomas Edison, Guglielmo Marconi, and Nikola Tesla, highlighting the challenges and innovations that defined the golden age of radio. With a focus on a specific project involving a one tube AM radio, this article offers insights into the evolution of radio technology and its enduring impact on society. Ideal for hams and radio enthusiasts interested in the roots of modern communication.

The author fixed a friend's Kenwood TS-850S radio, which suffered from Capacitor Plague, a common problem in 1990s electronics where capacitors leak and damage circuit boards. The CAR board, responsible for generating signals, was especially affected. The author cleaned the board, replaced the capacitors, and repaired a broken trace. Although the radio mostly functioned afterward, the "Slope Tune" control behaved abnormally. The cause seems to be a software issue, not a hardware one.

Detailing a Yaesu FT-857 and ATAS-120 installation in a 1997 Toyota Tacoma, the author used Polar Plot to map signal strength. Using a hand truck with a laptop, FT-817, and an Iron Horse antenna, they circled a chalk-outlined 100-foot diameter, revealing potential nulls towards the truck's rear and through the cab, offering insights into antenna performance.

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 showcases the use of ChatGPT for quickly creating a prototype application that maps out individual QSOs from a CZML map. The author details the process of using ChatGPT to generate code that positions and frames a Cesium Ion map based on data from a czml file. The page includes links to the original map, the prototype app, a video demonstration, and the mapped QSOs output. The content is aimed at hams interested in experimenting with AI tools for ham radio applications.

This page provides a detailed review and installation experience of a new 6 and 2 meter dual band Yagi antenna. The author shares insights on the purchase process, shipping, assembly, and performance of the antenna in their backyard setup. The content is useful for hams looking for information on dual band Yagi antennas, especially those interested in improving their contest operations or backyard installations. The author's personal experience and challenges with mounting the antenna on a small push-up mast are also discussed.

This article provides a comprehensive introduction to the decibel (dB), its logarithmic nature, and its applications in power, voltage, and antenna gain calculations. It explains how dB simplifies comparisons in electronics, telecommunications, and audio perception. The author clarifies key mathematical concepts, including power ratios, voltage doubling, and absolute levels like dBm and dBV. The discussion on S-units and antenna system gain is particularly relevant for radio amateurs. Overall, this is an informative and well-structured guide to understanding and applying decibels in technical fields.

For phased C-Poles, matching choke baluns are essential to maintain intended phasing, beam pattern, and gain. The author uses a low-loss, ferrite-core balun design with 19 turns of RG-174/U coax for optimal performance.

The influence of temperature changes in Common Mode Chokes. To get an indication of the impedance behavior when the core temperature changes, the author tested a CMC by heating it with a hairdryer, and measuring its temperature with an infrared thermometer. When the CMC temperature rises from 30C to 90C, the frequency of maximal impedance shifts down from ca.10 MHz to ca.7.2 MHz, or by a factor 1.4.

This webpage caters to EMRFD owners, offering insights into building popcorn receiver band-pass filters with Ladpac programs and EMRFD Chapter 3 knowledge. Through practical experiments and Ladpac tools, the author explores coupling capacitors' impact on filter response and return loss optimization. The content emphasizes empirical approaches, encouraging builders to embrace experimentation and learn from mistakes. Detailed examples and workflow suggestions aid hobbyist-level designers in creating customized filters, fostering a deeper understanding of filter design principles.

Manually programming a Yaesu FTM-100 with hundreds of channels can be very fustrating. In this article the author highlights the difficulty of entering data with small buttons and the need to look up information for each channel. To avoid this tedious process author used RT Systems software as a solution. This program simplifies programming by allowing selection based on the radio model, download of frequencies from resources like RFinder, and quick loading onto the radio. While paid unlike the free CHIRP software used previously, the author emphasizes the time saved compared to manual entry, making the cost worthwhile.

The article "Icom IC7300 RTC Fix" details the meticulous repair of an Icom IC-7300's faulty real-time clock (RTC). The author and a friend, Nacho, discovered the RTC was gaining an unacceptable 11 seconds per day. Investigations revealed the Seiko Epson RX8803LC RTC was far outside its specified stability. Despite replacing the RTC and a burned pullup resistor, the transceiver still malfunctioned, leading to the replacement of the processor. Post-repair, the clock's accuracy improved significantly, now gaining only 1.4 seconds per month. This narrative underscores the complexities of electronic repairs and the satisfaction of resolving intricate issues.

Improve the FRG-7 operation adding a home made digital frequency display. The author explains the challenges of using the analogue dial on the FRG-7 and how a digital display can be a useful solution. The page provides detailed information about the FRG-7's design and frequency conversion process. It also includes step-by-step instructions on how to connect an external frequency counter to display the kHz part of the frequency.

This thoughtful review details ajourney from the stock Elecraft KXPD2 paddle to an innovative pressure-sensor alternative. The author candidly describes issues with their original paddle—intermittent operation and loosening screws—before discovering VK3IL's pressure-sensitive design through QST magazine. The construction process, using a PCB and components generously shared by the designer, proved straightforward despite challenging SMD soldering. What stands out is the clever DIY housing solution: a "sandwich" of closed-cell foam encased in heat-shrink tubing that fits comfortably in hand. The ergonomic design allows effective single-handed operation for portable SOTA activations. The successful implementation has rendered the original paddle obsolete, leaving only the task of covering the radio's paddle port.

Connecting to the global *EchoLink* network via a web browser simplifies internet linking for licensed amateur radio operators. This web application provides a direct interface, eliminating the need for client software installation. Users can log in with their validated callsign and password to access the system, facilitating contacts with other stations, repeaters, and conferences worldwide, much like traditional VoIP applications but tailored for amateur radio. The interface offers essential controls for managing connections, including selecting specific stations or conferences from a dropdown list, initiating a connection, and disconnecting. Features such as a 'Call CQ' button allow users to signal their availability for a contact, while options for low bandwidth operation and accepting incoming connections optimize performance and accessibility. Audio device selection ensures proper microphone and speaker integration with the web client. Validation of an amateur radio license is a prerequisite for full access, ensuring that only authorized operators utilize the network. The system prompts unvalidated users to provide an email address and password to begin the validation process, which typically involves submitting proof of license. This free service extends the reach of amateur radio communications globally, bridging geographical distances through internet connectivity.

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.

The author struggled with receiving antennas on his property. After a standard Beverage on Ground (BOG) antenna failed, he built a Reverse Beverage on Ground (RBOG) using telephone cable. He details construction and testing, finding the RBOG outperformed other antennas in noise level, signal strength, and reception pattern. Software modeling helped optimize the antenna length. Unfortunately, the project ended when telephone cable from the second RBOG was stolen.

VE1ZAC's analysis details the performance of **MFJ927** and **SGC239** autotuners with portable HF vertical antennas, specifically comparing 31 ft and 43 ft configurations. The resource originated from challenges encountered during a Maritime QSO Party roving operation, necessitating a lightweight and easily deployable antenna system. Target bands for the contest included 80, 40, 20, 15, and 10 meters, with a maximum power handling of 100 W CW. The author utilized a 30-foot carbon fiber push-up pole to support a vertical wire element, noting its 2 lb weight and reliability. EZNEC modeling was employed to predict performance, showing favorable results for a 30-foot vertical with elevated radials, particularly on 40 and 20 meters. Feedpoint impedance measurements, taken with an AIM4170C, are presented for various HF bands, both with and without a 41-foot RG6 stub designed to reduce reactance on 80 and 20 meters. The stub significantly improved matching on these bands, easing the tuner's workload. Operational tests revealed issues with the MFJ927's reliability during contest setup, leading to reliance on the K3's internal tuner. The SGC239, tested post-contest, performed flawlessly. A detailed side-by-side comparison covers mechanical aspects, connection options, power bias, impedance range, board quality, and documentation. Modifications to the MFJ927, including a new aluminum case, white paint for heat reduction, and upgraded impedance-measuring resistors, are also described.