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This article describes how to make a quadrifilar helix (QFH) antenna easily, from inexpensive materials: uPVC plumbing pipe and RG-58U co-axial cable. A low-cost, easy-to-build Quadrifilar Helix (QFH) antenna for weather satellite reception using uPVC plumbing pipe and RG-58U coaxial cable. Unlike traditional designs requiring copper pipe and plumbing skills, this approach enables construction with basic tools and minimal technical expertise. The antenna's shorter, wider proportions favor higher elevation angles, reducing interference from horizon-level pager transmitters. Electrical connections are simplified at the antenna's apex, with the coaxial cable forming the radiating elements. Testing demonstrated consistent signal strength throughout satellite passes, proving effective weather satellite reception is achievable without precision engineering to sub-millimeter tolerances.

Amateur Contact Log (AC Log) by N3FJP is a commercial Windows-based general logging program designed for amateur radio operators, supporting Windows 7 through 11. It provides comprehensive tracking for various operating awards, including Worked All States (WAS), Worked All Counties, Worked All Countries (WAC), DXCC, VUCC, Grids, Zones, IOTAs, and Lighthouses. The software features a customizable user interface, allowing operators to display specific data fields and adjust font sizes. It includes built-in databases for counties and countries, facilitates queries by band, mode, or power level, and offers a bearing and distance calculator for DX contacts. AC Log also provides DX spotting via Telnet or packet TNC, supports keyboard CW, and can play wave files. The program offers full support for ADIF import and export, enabling seamless integration with external services like eQSL, QRZ, Club Log, and the ARRL's Logbook of the World (LoTW) for QSO uploads and confirmation downloads. It interfaces with popular transceivers from Elecraft, Icom, Kenwood, Ten Tec, and Yaesu, and connects with digital mode software such as WSJT-X, Fldigi, and JTAlert via API. AC Log includes a Net Manager form for group logging, prints basic QSL label strips, and integrates with QRZ and Ham Call lookup services. The software is fully networkable for multi-PC operation, supports Parks on the Air (POTA) logging, and displays worked entities and DX spots on a real-time world map. Full featured Trial version available for 45 days

Presents detailed plans and construction notes for a compact 3-element Yagi antenna specifically designed for the 50 MHz band, authored by Ken Willis, _G8VR_. The article, originally published in _Practical Wireless_ in 1989 and updated in 1999, outlines the design philosophy behind a small, gain-oriented antenna suitable for restricted QTHs. It covers element dimensions, boom length, and a unique coaxial _gamma match_ system, emphasizing a "plumber's delight" construction approach using readily available hardware. The resource details the author's operational experience, achieving _DXCC_ on 50 MHz with over 110 countries worked using this antenna. It also incorporates insights from computer simulation studies by _G3SEK_ and _W1XP_ using _MININEC_, which suggested minor adjustments to element lengths and spacing for improved front-to-back ratio, increasing it from 14dB to 31dB. The author compares theoretical performance with practical results, noting that while larger arrays might offer a few dB more gain, this compact design provides excellent performance for F2 propagation and general 6-meter DXing.

DXtreme Station Log 15 SE provides comprehensive logging functionalities for Amateur Radio operators, featuring robust _Logbook of the World_ (LoTW) support for automatic uploads, QSO record status capture, and QSL processing. The software integrates with _Afreet Omni-Rig_ for rig control and offers worked-before notifications for _WSJT-X_ and JTDX, streamlining digital mode operations. Its DX Spot Checker queries servers to indicate DXCC/VUCC status based on the user's database, utilizing Rich Site Feed or Grid Feed options. Key features include Improv Imaging and QSL Imaging for managing screenshots, documents, and QSLs, alongside Performance Reports for tracking station activity. The application incorporates AI functionalities, such as a Generic AI feature and a dedicated DXtreme GPT for specific instructions. DXtreme Interchange facilitates digitizing paper logbooks into ADIF-based project files, enabling rapid data entry and automatic field population. DXtreme Monitor Log 14, designed for radio monitoring, logs stations across the spectrum, including a Schedule Checker for broadcast stations from Aoki, EiBi, and FCC AM sites. It integrates with Afreet Band Master to identify needed Amateur Radio entities and supports reception report creation for QSLs.

Examines the operational differences between **quad** and **Yagi** antenna designs, focusing on their respective performance characteristics for amateur radio applications. The document highlights key metrics such as forward gain, front-to-back ratio, and bandwidth, which are crucial for effective DXing and contesting. It discusses how element configuration, boom length, and material choices impact the efficiency and radiation patterns of each antenna type across various HF bands. Practical considerations for antenna builders are addressed, including structural integrity, wind loading, and overall weight, particularly when using fiberglass spreaders for quads. The resource also covers precipitation static reduction in quads due to their closed-loop design and their ability to operate efficiently at lower elevations compared to Yagis. It provides insights into dual-polarization feed systems for quads, offering independent vertical and horizontal feed points for enhanced operational flexibility.

A self-supporting vertical antenna design for stationary-mobile HF-VHF operation is presented, emphasizing ease of construction with common materials like a fiberglass fishing rod and PVC pipe. The design focuses on creating a set of no-tuner monoband radiators for bands such as **2m**, **6m**, 10m, and 12m, with an overall radiator support length of 3.3m. The construction process details the assembly of the antenna base using a magnetic mount, PL-259 connector, and PVC pipe sections, which then supports the telescopic fishing rod. Radiator extensions are cut to achieve quarter-wave resonance on specific bands, with detailed instructions for 6m (50-51 MHz), 10m (28.5 MHz), and 12m (24.9 MHz). For lower HF bands like 15m, 17m, and 20m, the design incorporates base-loading coils, with specific turn counts provided (e.g., 21 turns for 20m). The project also suggests using an _antenna analyzer_ for precise tuning of extensions and coils, moving beyond theoretical values to achieve optimal performance. The author, _IK1ZYW_, notes that for 80m and 160m, the antenna becomes less efficient as a vertical, suggesting alternative configurations like an inverted-V dipole or asymmetrical inverted-L.

A 1.5-meter telescopic whip antenna project for the Yaesu FT-817 QRP transceiver is presented, offering a cost-effective alternative to commercial portable antennas like the Whip Miracle. The design incorporates a **toroidal matching unit** with a rotary switch for band selection and a toggle switch for fine-tuning the coil taps. This setup allows operators to achieve a low **Standing Wave Ratio (SWR)** across various HF bands, despite the inherent limitations of a physically short radiator on lower frequencies. The construction details include photographs of the completed unit, showcasing the compact enclosure and the integration with the FT-817. A simple schematic illustrates the coil tapping arrangement and the switching mechanism, guiding hams through the assembly process. The project emphasizes practical, portable operation for **QRP** enthusiasts, acknowledging that while performance on bands like 80m or 40m will be modest, it can still facilitate contacts under favorable conditions with skilled operation.

Facilitates reliable two-way communication under challenging propagation conditions, WSJT-X provides a suite of digital modes optimized for weak-signal operation across the amateur bands. These modes, including FT8, FT4, and Q65, are designed to decode signals significantly below the noise floor, enabling DX contacts, EME (Earth-Moon-Earth), and meteor scatter QSOs with modest station setups. The software supports various T/R sequence lengths and tone spacings, tailored for specific propagation phenomena and band characteristics, such as JT9 for MF/HF with **2 dB** greater sensitivity than JT65, and MSK144 for VHF meteor scatter. WSJT-X also integrates specialized tools like _MAP65_ for wideband EME reception with polarization matching to counter _Faraday rotation_, and QMAP for wideband Q65 reception with Earth-Moon-Earth Doppler correction. These companion programs extend the software's capabilities for advanced weak-signal work, particularly on VHF, UHF, and microwave frequencies. The project, maintained by Joe Taylor, K1JT, and the WSJT Development Team, is the official home and reference implementation for these weak-signal digital communication protocols. Recent releases, such as _WSJT-X 3.0.2_, introduce enhancements like the QMAP program, Q65 Pileup, and SuperFox mode, which offers approximately **+10 dB** system gain for Fox-and-Hound operations.

Demonstrates the construction of a **remote antenna tuner** utilizing a standard radio-controlled (RC) servo mechanism to adjust a variable capacitor. The design focuses on enabling remote tuning for narrow-bandwidth antennas, specifically mentioning frame and packing crate antennas, from within the shack. It covers the mechanical arrangement for integrating the servo with a capacitor and provides a circuit diagram for a control unit that generates the necessary 0.5mS to 1.5mS pulse-width modulation (PWM) signals to drive the servo's 180-degree rotation. This setup was successfully tested with up to 20 watts RF power without arcing or adverse effects on the servo, though tuning was performed at 1 watt for VSWR readings. The resource highlights the use of inexpensive, readily available components, such as Futaba servos, and details critical considerations like power supply decoupling with a 47uF capacitor to prevent unintended servo movement upon power-off. The system provides a practical solution for optimizing antenna performance for specific frequencies without manual adjustment at the antenna itself.

Ferrite Toroidal Cores, Magnetic Properties of Ferrite Materials, EMI - RFI Suppression Design Considerations, Ferrite Beads, Ferrites for RFI Ferrite Cores for RFI Suppression by CWS ByteMark

The Flower Pot Antenna project details a portable dual-band antenna primarily operating on 10 meters, with secondary resonance near the 30-meter band. Construction involves winding RG58 coaxial cable uniformly around a large plastic flower pot, approximately 70cm high with a 60cm top diameter. The design eliminates the need for radials, contributing to its compact and lightweight nature. Key construction steps include soldering the inner conductor to the shield at one end of the wound cable and connecting the wound cable's shield to the rig cable's inner conductor at the base. An LC network, comprising a variable capacitor (0-200pF) and an inductor (10 coils, 5cm diameter, 2mm wire), is inserted between the wound cable's inner conductor and the rig cable's shield. Tuning is performed with an antenna analyzer, adjusting cable length and the variable capacitor for optimal impedance on 10 meters. The antenna performs effectively when installed horizontally.

Demonstrates adapting the _Moxon rectangle_ antenna design for 2-meter VHF operation, highlighting its unique characteristics for specific applications. It details how the antenna's small size and distinctive far-field pattern, typically associated with HF, can be effectively utilized on VHF. The resource provides modeled dimensions for three different element diameters (1/4", 1/2", 1") and discusses the necessary adjustments to maintain optimal performance, such as gap spacing and element lengths, to achieve a 50-Ohm feedpoint impedance. The article presents predicted performance data, including gain (dBi), front-to-back ratio (dB), and feedpoint impedance (R, jX) across 144, 146, and 148 MHz. It analyzes free-space azimuth patterns and discusses the antenna's behavior when horizontally and vertically polarized over ground, including its suitability for fixed installations, repeater applications, and even satellite communications. Construction considerations, such as bending elements and maintaining critical gap distances, are also addressed. Furthermore, the content explores advanced configurations like using two back-to-back rectangles for broader coverage and a crossed-Moxon setup for circular polarization, suggesting potential for urban communication and satellite work. The author, _L. B. Cebik, W4RNL_, emphasizes the Moxon's strengths in broad bandwidth, wide beamwidth, and high front-to-back ratio, rather than maximum gain.

A **mobile HF multiband antenna** project details the construction of a center and top-loaded design, optimized for 10 through 80 meters. This antenna incorporates a capacity hat positioned high on the whip for enhanced efficiency, differing from commercial bugcatcher designs. The coil construction prioritizes high Q and minimal loss through an air core, open spacing, and heavy gauge wire, contributing to its lightweight nature and suitability for portable operation with a proper counterpoise. Band switching is achieved by manually moving a jumper plug to various tap points on the coil, allowing for operation across multiple bands, with 17m being resonant when the coil is bypassed. The design, a result of nine months of experimentation by N1LO, includes detailed instructions for modifying a Hamstick antenna base, creating a jumper wire, and assembling the capacity hat using stainless steel wire and silver-bearing solder for robust connections. The loading coil utilizes nylon grommet strips around a PVC pipe for an air-core winding, ensuring high efficiency. Tap sockets are fashioned from silver-plated 5-way binding posts, providing low-resistance RF joints for band selection. Guidance on tap point determination emphasizes using an antenna analyzer like the MFJ 259B or 269 to achieve resonance, especially on 40m and 80m where feedpoint resistance can be low. The document also covers the installation of monofilament stays to maintain antenna uprightness at highway speeds, with specific attachment points for stability.

The _Morgain_ antenna for 40/80 meters is a straightforward and cost-effective wire antenna design, requiring careful tuning for optimal performance across two bands with low SWR. Construction involves creating 12 cm PVC spacers with three holes for wire insertion, along with larger terminals for anchoring and connector housing, which should be sealed with silicone. The provided measurements detail the specific lengths for the antenna elements, crucial for achieving resonance on both 40m and 80m bands. Tuning the Morgain antenna necessitates fabricating four wire segments with pins to temporarily connect and adjust the bridging points symmetrically for both 40m and 80m. This iterative process, though time-consuming, ensures the antenna functions effectively for decades once the precise connection points are soldered and protected. The design emphasizes ease of construction and long-term stability, making it a practical solution for hams seeking a dual-band wire antenna.

This drawing shows a simple 10 meter wire J-pole antenna designed for 28.4 MHz. It is a vertical, end-fed Zepp-style antenna made from common materials and intended for easy home construction. The main radiating element is a straight length of stranded copper wire, either 14 or 18 gauge, cut to about 16.5 feet. At the top, the wire is supported by an insulator, allowing the antenna to be hoisted vertically. The matching section is made from 450-ohm ladder line, approximately 7 feet 9.5 inches long, and shorted at the bottom. This matching stub transforms the impedance so the antenna can be fed with coaxial cable. The feed point is tapped about 6 inches above the bottom of the stub, with the shield and center conductor connected at the proper points. A choke balun is formed with five turns of RG-58 coax in a 4-inch diameter loop to help reduce unwanted RF on the feed line. The drawing notes that this antenna has about 0 dBd gain, similar to a dipole, but offers an omnidirectional pattern and low-angle radiation when installed high. Its main advantage is practical performance, simple construction, and effective coverage for 10 meter operation.

This sketch will read RF power and SWR from any SWR bridge, designed to work on VHF UHF bands

The _59+ Log_ software, part of the 59+ collection, functions as a logging tool for Windows operating systems, specifically tested on Windows XP where its logbook feature operates smoothly. This collection also includes _59+ CW_, a module designed for Morse code operations, enabling keying of the COM port for transceiver control or simply listening to CW signals via the speaker. The software package, originally hosted on idealog.net, is now available for download as 59soft14.zip (3.4 MB) from IW5EDI's site. While the logbook application is functional, the _59+ CW_ application may encounter issues on newer Windows versions, as indicated by a failure to start on Windows XP during testing. The analyzer and convert modules within the 59+ suite require registration and do not operate in trial mode. Development and support for this software have been discontinued.

M1PAF's 20 Meter Vertical Moxon antenna design, based on Pete Mills' EZNEC model, utilizes a push-up GRP mast and Tufnol plate for mounting cross arms, minimizing metallic elements within the beam. Hydraulic pipe clamps, also plastic, secure the tube clamps, with only two bolts and a plate being metallic. Dog bone insulators with Kevlar line and snap links facilitate quick wire element attachment, ensuring tension in all dimensions. The antenna's support structure includes Tufnol guying rings for Kevlar guys, providing stability against high winds. The cross arms are constructed from three 1-meter sections, allowing for convenient packing. This portable setup was successfully deployed adjacent to the ocean, enabling over 4500 QSOs in six days with 100W, achieving easy contacts into Japan and Asia. The design emphasizes ease of erection by a single operator and robust performance in challenging environments. Components for the cross arms were sourced from Spiderbeam. Further information is available via M1PAF's QRZ.com details.

Multiplatoform freeware DSP software. Linrad has its origin in software that was developed for 144 MHz EME CW but it is quite general and should be seen more like a kit for designing a receiver that a receiver for some particular usage. It can be used as a CW receiver with a small time delay and a fast waterfall graph. A dsp for conventional receiver to imporve signals readability, a spectrum analyzer.

Log4OM is a free logging software designed for amateur radio operators who require an integrated environment for station management and QSO logging. It is widely used by DXers due to its strong database capabilities and its integration with common online services. The program uses a structured SQL database and supports large logbooks without noticeable performance degradation. One of its key features is **CAT Control**, which allows direct communication with many transceivers for automatic frequency and mode detection. The **DX Cluster Client** provides real-time spotting with filtering and band/mode tracking, helping operators quickly identify new DX opportunities. Log4OM integrates with several external confirmation systems. Built-in support for **Logbook of The World (LoTW)** and **eQSL** allows automatic upload and download of confirmations. The software also includes **Award Tracking**, enabling operators to monitor progress toward DXCC and other award programs directly from the log. Additional capabilities include **Callbook lookup** via services such as QRZ, **ADIF import/export**, and customizable **QSL management** for both electronic and paper cards. The interface is modular, with panels that can be arranged depending on operating preferences. Log4OM does not include integrated digital mode engines, so digital operation normally relies on external programs such as WSJT-X or FLdigi connected through standard interfaces. Overall, Log4OM provides a comprehensive logging environment suitable for both casual operation and serious DX chasing, with a feature set comparable to many commercial logging applications.

EasyPal is a sophisticated digital Slow-Scan Television (SSTV) application that utilizes soundcard technology to encode and decode SSTV signals. Developed by the late Erik Sundstrup (VK4AES SK), this software has evolved into a versatile communication tool for amateur radio operators, extending beyond basic image transmission capabilities. EasyPal implements Digital Radio Mondiale (DRM) encoding technology, enabling efficient data transmission over narrow 2.5 KHz channels on both HF and VHF frequencies with remarkable speed. The application supports multiple file formats, including jpg, pdf, txt, doc, and xls, as well as specialized forms such as ICS-213 and ICS-213 (ARES). Additionally, EasyPal offers email functionality through designated repeater stations with internet access. Its responsive development history and robust feature set have established it as a premier digital SSTV solution in the amateur radio community, though users of Windows 11 should note specific configuration requirements to ensure optimal performance.

The resource provides detailed information about a five-band indoor magnetic loop antenna designed for amateur radio operators. This antenna is capable of operating on the 20, 17, 15, 12, and 10 meter bands, making it a versatile choice for various HF communications. Constructed from a single 3-meter length of 22 mm copper tube, the design emphasizes compactness and efficiency, which is particularly beneficial for operators with limited space. The page includes insights into the construction process, tuning, and operational tips, catering to both novice and experienced users. In addition to the technical specifications, the resource also discusses the advantages of using a magnetic loop antenna indoors, such as reduced interference and improved performance in urban environments. It serves as a practical guide for those interested in building their own antenna, offering a straightforward approach to antenna design and construction. Overall, this resource is a valuable addition to the toolkit of amateur radio enthusiasts looking to enhance their station with an effective indoor antenna solution.

The project details modifications to an ARK-40 QRP CW transceiver kit, specifically replacing its original thumbwheel frequency selectors with a **BASIC STAMP BS-II microcontroller** and an optical shaft encoder. The redesigned control circuitry outputs a BCD code to the ARK-40's synthesizer, enabling more convenient knob-type tuning. This modification significantly alters the user interface, moving from discrete frequency selection to continuous tuning. Operating frequency is presented on an LCD readout, offering two distinct display modes: a "bandspread dial" mode that simulates an analog dial scrolling across the display in 1 kHz increments, and a conventional digital readout with 100 Hz resolution. Pushing the main tuning knob toggles between these modes, providing both rapid band traversal and fine-tuning capabilities. The software for the BASIC Stamp is written in P-Basic, addressing the challenge of accurate analog dial simulation. Physical modifications include fabricating a custom PC Board for the STAMP, mounting it with an L-bracket to the optical encoder, and creating a new front panel. The front-mounted speaker was relocated to accommodate the new tuning knob and display, transforming the **ARK-40 transceiver** into a more user-friendly rig with its built-in CW keyer and 5 watts of power.

The directory lists several files, including `_template1.html` and `_template2.html`, last modified in 2006 and 2004 respectively, indicating a historical web project. Key scripts like `hfcc_cfm.pl` and `index.cgi`, updated in 2011, suggest a **CGI-based application** for searching shortwave broadcast schedules. The presence of `_template1.tpl` and `_template2.tpl`, both modified in 2015, points to a templating system for dynamic content generation. The file `hfcc_create-fill_mys..>` (likely `hfcc_create-fill_mysql.pl`) implies interaction with a database, possibly MySQL, for storing and retrieving **HFCC (High Frequency Co-ordination Conference)** schedule data. The `lang.cgi` script, last updated in 2002, suggests early support for multilingual interfaces or language-specific content delivery. The `q.txt` file, a small 804-byte text file, could be a query log or a simple data file. The overall structure indicates a system designed to process and present shortwave broadcast information, likely by querying a database of scheduled transmissions on various HF frequencies. The file modification dates suggest the project was actively developed and maintained over a period spanning more than a decade, with core components last updated around 2011 and templates in 2015.

Demonstrates the construction and on-air performance of the _NB6Zep_ antenna, a modified 20-meter Extended Double Zepp design optimized for multi-band operation from 40 through 10 meters. The resource covers basic design principles, including dimensions of 66 feet horizontal and 5 feet vertical elements, and specifies open ladder line or TV twin lead for the transmission line. It details material selection for low-cost wire antenna construction, such as 18 AWG wire for the legs and ceramic or plastic insulators, along with practical tips for soldering connections and insulating against moisture. The author, NB6Z, shares insights from extensive _EZNEC_ modeling to optimize the antenna's total length for a 40-meter half-wave dipole footprint and feed line length for direct tuner connection. The article presents field results, including successful _PSK31_ contacts from Oregon to the East Coast on 40 and 30 meters with 50 watts, even at a low height of 6 feet. It provides detailed performance characteristics for each band, noting the _NB6Zep_'s highest gain (over 3 dB) and sharp, medium-angle lobes on 20 meters, which yielded strong DX reports to locations like Korea, Japan, and Argentina. For 17 and 15 meters, it describes a butterfly-like pattern with broad lobes, while 12 and 10 meters exhibit narrow, directional lobes in an "X" configuration. The author also shares personal experiences operating successfully for over a decade in an antenna-restricted environment using the NB6Zep and other stealth wire antennas.

Constructing a compact, directional antenna for the 6-meter band presents unique challenges, especially for operators with limited space or those seeking portable solutions. This project details the build of a 50 MHz Moxon rectangle, specifically engineered for balcony or temporary mast deployment, using readily available materials from a typical hardware store. The design emphasizes ease of construction and portability, allowing for quick setup and breakdown. The antenna's dimensions are precisely calculated using _Moxgen_ software for 50.200 MHz, ensuring optimal performance. Key construction techniques include using aluminum U-channel for elements, fiberglass driveway markers for insulation, and cable ties for secure assembly. The guide provides detailed instructions for fabricating the driven element, reflector, and boom, including a clever method for creating foldable element tips for transport. Performance observations indicate a respectable front-to-back ratio, capable of reducing an S7 signal to S0 when pointed away, and a modest gain over a simple wire antenna. The design incorporates a ferrite bead choke balun at the feedpoint to mitigate common-mode current and reduce shack noise, a critical consideration for urban or apartment-based operations.

Thierry LOMBRY, ON4SKY, develops in several long articles all you need to know about antennas, their design and performance, for both amateurs and SWL

Presents a catalog of **QRP** transceivers, antenna tuners, and related accessories for amateur radio operators. The product line includes the ZM-2 antenna tuner, designed for efficient impedance matching across HF bands, and the NW-series QRP transceivers, offering low-power CW operation. Additionally, the site details various ladder line insulators and specialized connectors, emphasizing robust construction for field deployment and home station use. Each product listing provides specifications, operational parameters, and pricing information. Compares the features of different **QRP transceiver** models, such as the NW-40 and NW-20, highlighting their respective band coverage and power output capabilities. The ZM-2 tuner's performance is detailed with typical SWR reduction figures for various antenna types, demonstrating its utility for portable and fixed stations. Customer testimonials and product images illustrate the practical application and build quality of EMTECH's offerings, providing insights into their durability and ease of integration into existing amateur radio setups.

This design represents the smallest practical antenna for Oscar-13 mode-S. Perfect beacon reception at all times is possible, and acceptable SSB even at 43,000 km range.

A 144 MHz kilowatt amplifier project details the construction and performance of a high-power VHF linear using the GU74b tetrode. This Russian tube, equivalent to the Svetlana 4CX800, is noted for its conservative datasheet ratings, performing closer to 800-1000W anode dissipation in practical applications. The design prioritizes compactness and achieves 1.2 kW output with only 20W of drive power, demonstrating a 70% efficiency at 2.5 kV plate voltage. The amplifier has been successfully deployed in demanding _EME_ (Earth-Moon-Earth) operations since June 1994. Challenges encountered during development included achieving stability with a grid-1 input configuration. The author, _CT1DMK_, opted not to publish the full design due to its complexity, suggesting it might be difficult for less experienced builders to replicate successfully. However, he invites direct contact for those with specific interest in the design. Future plans include a "144MHz GS35b compact amplifier" project, promising another kilowatt-plus design. This resource offers insights into high-power VHF amplifier construction and the practical application of specific power tubes.

The SoftRock-40 is a small, low-cost, good-performing "software defined radio" receiver that plugs into a computer USB port and delivers I-Q audio signals to the computer's sound card. It was designed by Tony Parks, KB9YIG and Bill Tracey, KD5TFD as an "SDR sampler project" for hams everywhere to easily try out software defined radio.

Presents a crystal-controlled CW transmitter design for the 40-meter band, delivering 5 to 7.5 watts output power. The circuit innovatively employs an _IRF510_ power MOSFET in the final amplifier stage, diverging from conventional bipolar transistors. This design offers high gain, nearly 90% efficiency, and robust resistance to high SWR, allowing 30-second key-down operation into an open circuit without damage. A critical aspect is the precise adjustment of the MOSFET gate bias via a 10K trimmer pot, _R10_, to maintain quiescent current between 5 and 10 mA, preventing thermal runaway inherent to bipolar devices. The prototype was constructed on a _Radio Shack universal board_ and achieved immediate operational success. The design requires a 15-volt Zener diode to protect the MOSFET gate from overvoltage. Component sourcing information is provided, including specific crystal frequencies (7.040 MHz or 7.122 MHz) available from _Dan’s Small Parts & Kits_ or Doug Hendricks. The fixed frequency can be slightly adjusted with a trimmer capacitor. A complete bill of materials, including resistor values, capacitor types, toroid specifications, and transistor part numbers, is detailed, alongside a clear schematic diagram.

Presents a detailed construction guide for a 2-element _Moxon rectangle_ antenna optimized for the 10-meter band, designed by L. B. Cebik, W4RNL (SK). This resource demonstrates how to build a compact beam antenna using readily available hardware store aluminum tubing, fitting within a 12-13 foot width. It highlights the antenna's performance characteristics, including a gain comparable to a 2-element Yagi (11+ dBi) and a front-to-back ratio exceeding 20 dB between 28.3 and 28.5 MHz, with an SWR below 2:1 across the entire band. The design emphasizes direct 50-ohm coax connection without a separate matching system, though a 1:1 choke _balun_ is recommended. The guide provides practical advice on element construction, corner fabrication using L-stock or radius-bent tubing, and the critical side-to-side length adjustment for SWR optimization. It details the feedpoint assembly using a chassis-mounting coax connector and discusses element-to-boom plate options, including spar varnished plywood or LE plastic. The author's experience with a test model on a 20-foot mast confirms stable feedpoint characteristics and excellent performance even at lower heights. The document also includes insights into the antenna's free-space azimuth patterns, noting a broad forward lobe and significant front-to-back rejection. It contrasts the Moxon with traditional Yagis, positioning it as an effective, home-buildable alternative for compact sites or _Field Day_ operations, particularly beneficial during periods of increased 10-meter activity.

Demonstrates BBLogger, a **freeware** logging application designed for both amateur radio operators and Short Wave Listeners (SWLs). Developed by IK2VIW, IZ2BKT, and IK2UVR, this software provides comprehensive station management capabilities, including **CAT control** for various transceivers, integration with digital mode software like WSJT-X, JTDX, and MSHV, and robust QSL management features. The application supports a wide array of functions such as DX cluster interfacing, mapping, awards tracking (including custom awards), and direct integration with services like LoTW, eQSL.cc, and ClubLog for QSL confirmations and OQRS requests. It also includes utilities for ADIF to CSV conversion and vice-versa, catering to diverse logging and data management needs. Recent updates, such as version 13.1, introduce a web server for log management from any device, allowing remote access and control. The software has improved ADIF import capabilities, including time settings for duplicate QSO detection, and enhanced filtering options for log searches. Performance improvements include faster automatic updates and manager database synchronization, along with optimized log checking at startup. Earlier versions added support for FT8 and FT4 modes, refined OQRS integration with ClubLog, and expanded QSL/label printing functionalities, enabling users to select specific callsign types (OM, SWL) for printing. The developers emphasize compatibility with Windows 10/11 for full functionality, noting limitations when running on older operating systems like Windows 7 due to modern security protocol requirements.

Catalogs a diverse array of Software Defined Radio (SDR) projects and realizations, systematically classified by their sampling methodologies and underlying hardware architectures. The resource delineates projects into categories such as those utilizing soundcard sampling of traditional transceiver audio outputs (Type Ia), mono soundcard sampling of intermediate frequencies (Type R1x-x-xx), stereo soundcard sampling of I/Q IFs (Type Q1x-x-xx), dedicated stereo audio ADC sampling of I/Q IFs (Type Q2x-x-xx), direct antenna RF signal sampling with off-the-shelf acquisition boards (Type R3x-x-xx), dedicated RF ADC sampling of analog IFs (Type R2x-x-xx), dedicated RF ADC sampling of direct antenna RF signals with ASIC-based processing (Type R4x-A-xx), FPGA-based processing (Type R4x-F-xx), and specialized IF chipsets combining ADC and DDC functions (Type Dxx-S-xx). Each entry provides a brief description, often including pricing, availability of source code, and specific hardware components like ADCs, DACs, DDS, and FPGAs. The compilation presents various practical applications, from PSK31 and Packet radio implementations to adaptations of the DRM standard for amateur radio bandwidths, such as Hamdream and WinDRM. It features specific hardware designs like the SoftRock-40 for the 40-meter band, the Firefly SDR for 30m and 40m, and more complex systems like the Quicksilver QS1R, which employs a 16-bit 130 Msamples/s ADC and an Altera Cyclone III FPGA. The resource also lists sample processing software, RF front-end designs, and academic/commercial SDR initiatives, offering insights into different approaches for I/Q conversion and digital signal processing in SDR systems.

Demonstrates the construction and performance of an updated ZS6BKW multiband dipole, a variant of the _G5RV_ antenna, specifically designed for HF operation. The article details a real-world installation using 13.5m copper wire elements and 12.2m of 450 Ohm ladder line, configured as a sloping inverted-V with the apex at 10m and ends at 4m above ground. It covers the critical aspect of impedance matching, incorporating an 8-turn choke balun at the feedline transition to RG-58U coax to mitigate RF common mode current. Measurements confirm favorable SWR readings below **1.3:1** on 7.1 MHz, 14.11 MHz, 18.06 MHz, and 24.8 MHz, indicating effective resonance across 40m, 20m, 17m, and 12m bands. The installation also shows usable SWR dips on 3.55 MHz (5:1), 29.02 MHz (2:1), and 50.84 MHz (3:1), extending its utility to 80m, 10m, and 6m with an antenna tuning unit. Initial on-air results report clear reception of stations over **5000km** away, validating its DX potential.

SM0DTK's 40-meter Moxon antenna project details the construction and deployment of a wire Moxon rectangle, specifically dimensioned for the 7 MHz band. The resource outlines the use of a _Moxon Rectangle Generator_ for calculating wire lengths and the fabrication of plexiglass supports for corners and the feeding point. It describes the practical challenges of elevating the antenna to approximately **14 meters** using an aluminum tube and fiberglass rod, emphasizing the adjustment process for achieving the correct rectangular shape. The article presents comparative results against a 60-meter long-wire and a full-size 40-meter ground plane antenna. The Moxon demonstrated significant directional gain towards the west, facilitating DX contacts in the Caribbean with **100 watts**, while simultaneously reducing QRM from strong eastern European stations. The SWR was reported as perfect without the need for an antenna tuner, validating the design's effectiveness for targeted signal enhancement and interference mitigation.

WB2VUO presents a practical examination of effective HF mobile antennas, focusing on the inherent efficiency challenges encountered on the lower bands, specifically 160, 80, and 40 Meters. The resource delves into the necessity of loading coils for mobile operation below 21 MHz, where full-sized antennas are impractical. It contrasts base-loaded and center-loaded designs, noting that base-loaded antennas are simpler for the average ham to construct but offer lower efficiency compared to center-loaded configurations. The author provides specific data for an 8-foot whip, detailing its electrical length and _radiation resistance_ across various HF bands, from **0.08 ohms** on 160 Meters to **16.1 ohms** on 12 Meters. This data highlights the extremely low radiation resistance on lower frequencies, which significantly impacts feedpoint impedance due to ground and feedline losses. The discussion includes practical considerations for feedpoint impedance, noting that a typical 8-foot whip on 10 Meters might present 30-45 ohms, allowing for acceptable SWR without an ATU. Construction sketches illustrate both base-loaded and center-loaded mobile antennas, with advice on material selection like galvanized steel for rugged bottom sections. The article also includes coil value charts from the _ARRL Mobile Manual_ for both base and center loading, emphasizing the importance of using large diameter wire to minimize losses and suggesting capacity hats to reduce coil inductance and improve performance on 160-40 Meters.

The Inverted L antenna is a versatile and efficient design suitable for small gardens, allowing amateur radio operators to operate on multiple bands. This project outlines the construction of a 5-band inverted L antenna, which can cover HF bands effectively. The design is particularly advantageous for those with limited space, as it requires minimal ground space while providing good performance. The antenna can be easily constructed using common materials, making it accessible for both beginners and experienced hams. In this guide, GM0ONX shares detailed instructions on how to build the inverted L antenna, including dimensions and tuning tips. The project emphasizes the importance of proper installation and grounding to ensure optimal performance. Additionally, it discusses the antenna's compatibility with various transceivers and the potential for portable operation. This resource is ideal for hams looking to enhance their station with a multiband antenna that performs well in limited space.

Multi-band centre-fed antenna capable of very efficient operation on all HF bands, specifically designed with dimensions which allow it to be installed in gardens and other open spaces which accommodate a reasonably-straight run of 31.1m (102 ft) for the flat-top standard model.

This resource details the construction and feeding of a vertical Moxon antenna specifically designed for the 20-meter band (14 MHz). It addresses the common issue of impedance variations at the feed point of vertical dipoles and Moxons, which typically requires the coax to exit at a specific angle (45-90 degrees) to maintain a good 50-ohm match. The presented solution involves opening the lower corner of the fed element and utilizing a transformer for impedance matching, simplifying installation and improving SWR. The alternative feeding method provides a stable match, eliminating the need for precise coax routing to achieve a low SWR. This design offers a practical improvement over conventional vertical Moxon feeding, making deployment significantly easier. The author, SM0DTK, confirms the efficacy of this setup, noting its fine performance and reduced installation complexity compared to traditional methods.

Facilitates efficient logging of amateur radio contacts, offering a robust solution for hams managing their station activities. The software integrates _CAT control_ capabilities, allowing direct interfacing with popular transceivers from manufacturers like Yaesu, Icom, and Kenwood. This feature streamlines the logging process by automatically capturing frequency, mode, and other QSO details directly from the radio, reducing manual entry errors and improving operational efficiency during contests or DXing. _HAM-LCT_ includes a comprehensive database, enabling users to store and retrieve contact information, QSL data, and other relevant details for each QSO. The program supports various operating modes and provides tools for searching and filtering log entries, which is beneficial for award tracking and station analysis. Its design focuses on providing a user-friendly interface for everyday logging tasks. While the original author, _HB9CQV_, has discontinued development of HAM-LCT in favor of a newer logging application, this version remains available as a functional freeware option for Windows users seeking a dedicated logbook with integrated rig control.

CWLab02 demonstrates a Windows-based software solution for Morse code enthusiasts, enabling both CW and CCW (Computer-Generated CW) sending and receiving within a single, integrated window. The program incorporates an improved CW interface, aiming to simplify the process of decoding and generating Morse code signals. It provides a straightforward method for hams to practice their CW skills or integrate computer-generated code into their operations, supporting real-time interaction with Morse code transmissions. The software's design focuses on ease of use for CCW operations, allowing operators to quickly generate and transmit code. While specific technical details on its decoding algorithms or WPM range are not provided, the emphasis on an "improved CW" suggests refinements in its signal processing capabilities. The ability to send and receive in the same window streamlines the user experience, offering a practical tool for training, casual QSOs, or integrating into a digital shack setup.

One common challenge in antenna systems is mitigating common-mode current on the feedline, which can distort radiation patterns and introduce RF in the shack. This project details a 1:1 balun design that ingeniously avoids traditional ferrite beads, often a costly component, by substituting them with steel wool. The steel wool, when integrated into the balun's construction, effectively attenuates unwanted RF on the outer braid of the coaxial cable, ensuring that the antenna radiates efficiently and as intended. The construction involves winding coaxial cable through a PVC former, with the steel wool strategically placed to provide the necessary common-mode impedance. This method offers a practical and economical alternative for hams looking to build effective baluns without the expense or availability issues associated with ferrite cores. The design principles focus on creating a balanced feed to the antenna, crucial for optimal performance of dipoles and other balanced radiators. Experimentation with such designs can lead to improved field results, particularly for those operating with limited budgets or seeking innovative solutions for their antenna systems. The simplicity of using readily available materials like steel wool makes this a compelling build for many radio amateurs.

A small and inexpensive measurement device designed to determine antenna performance across the amateur bands through use of automatically collected SWR readings

The KD1JV "Melt Solder" Digital QRP SWR/Power Meter operates across the 160m to 6m bands, featuring 9.9-watt and 990-milliwatt power scales, a peak hold mode for SSB, and a VSWR scale from 1:1 to 9.9:1. It utilizes a _Stockton directional coupler_ wound on a single binocular core and an _Atmel AVR ATtiny26L_ microcontroller for processing. The design incorporates _W7EL diode compensation_ in a non-inverting amplifier feedback loop to address diode voltage drop and non-linear behavior at low power levels, with software corrections applied for improved accuracy, particularly at QRP power levels up to 5 watts. Construction details include parts placement, transformer winding instructions for #26 magnet wire, and calibration procedures using a 1.5V alkaline battery or an oscilloscope with a 50-ohm dummy load. Packaging options are discussed for fitting the board into an Altoids tin or a deeper Whitman’s Sampler tin, with considerations for battery life extension by adding a third or fourth battery. Accuracy tests performed at 7 MHz compare readings against a True RMS power meter based on an _Analog Devices AD8361_ chip, showing typical deviations of 0-5% across various power levels.

Presents a practical approach to constructing a portable, lightweight antenna support structure, ideal for field operations or temporary installations. The design utilizes readily available PVC pipe sections, allowing for a total height of **20 feet** and a transportable weight of **25 lbs**. Detailed material lists specify various PVC pipe diameters and lengths, along with couplers, tees, and elbows, facilitating a modular assembly that can be easily disassembled for transport. Accompanying the tower design, the resource also outlines the construction of a _MicroVert_ antenna, including formulas for radiator length, capacitance, and inductance. It provides guidance on creating a current balun using ferrite beads or a coax coil, and calculating counterpoise length for optimal performance. The antenna section includes a schematic diagram illustrating the connection of the SO-239 connector and counterpoise.

Demonstrates an online **CW** audio decoder tool, currently under active development, designed for analyzing and decoding Morse code. Users can upload audio files containing Morse code or record live audio input via a microphone, with processing handled entirely in JavaScript using the Web Audio API. The software analyzes the audio, attempting to determine the pitch and speed, and then decodes the message, providing options to compare the decoded output against a predefined message or a perfectly timed version. The interface allows for setting optional comparison messages, character speed in WPM, and Farnsworth speed. It also features interactive charts for visualizing the audio analysis, where users can zoom with the mouse wheel and pan by dragging. Specific buttons highlight different element types such as intra-character space, inter-character space, extra elements, missing elements, and replaced elements, aiding in detailed signal analysis. Built-in test files are available for immediate analysis, allowing users to quickly evaluate the decoder's performance. The tool is noted to work with specific browsers and is presented as a testing platform for user feedback, indicating ongoing refinement of its decoding algorithms and user interface.

Version 1.4.6 of _AAVoice_ functions as a digital voice processor for amateur radio, designed to operate on Windows platforms from 9x through 10. This software leverages pre-recorded WAV files for transmission, allowing operators to send pre-defined messages or calls efficiently. Its core functionality includes PTT control, which can be managed through a simple circuit connected to a COM port, providing a reliable interface for radio keying. The program offers extensive macro capabilities, streamlining repetitive transmissions during contesting or DXing. It also features direct integration with the _AALog_ logger, enhancing workflow for those using DXsoft's suite of tools, and can interface with other compatible programs via its COM-interface. Author Alexander Anipkin designed _AAVoice_ to require a working sound card, and it comes with a basic set of sound files. Users can easily create additional WAV files using standard Windows sound recording utilities, ensuring flexibility in customizing audio content for various operating scenarios.

The ZS6BKW multiband HF antenna, a design by ZS6BKW (G0GSF), functions effectively on multiple HF bands without requiring an Antenna Tuning Unit (ATU) for 40, 20, 17, 12, 10, and 6 meters. This antenna, approximately **27.51 meters** (90 feet) long with a 12.2-meter (40-foot) open-wire feeder, is a direct descendant of the _G5RV_ but offers superior multi-band resonance. It can be deployed as a horizontal dipole or an inverted-vee, with the latter requiring only a single support and maintaining an apex angle of at least 90 degrees to prevent signal cancellation. Performance data, recorded with an MFJ Antenna Analyser, indicates SWR values of 1:1 on 7.00 MHz (40m) and 14.06 MHz (20m), with SWR below 1.3:1 on 17m, 10m, and 6m. While primarily designed for these bands, the antenna can be adapted for 80m, 30m, and 15m with an ATU, preferably at the balanced feeder's base. The use of 450-ohm twin-lead for the feeder is recommended over 300-ohm for improved strength and reduced losses, especially in adverse weather conditions. This design, originally published in _RadCom_ in 1993 and featured in Pat Hawker’s "Antenna Topics," provides a compact and efficient solution for HF operation, particularly for those with limited space or resources.