Search results

Design your VHF UHF Yagi antenna online, a JavaScript enhanced web page that implements the design of an antenna for 2m and 70cm bands. This page offers a streamlined experience for Yagi antenna design enthusiasts. It assumes prior knowledge of Yagi design principles, minimizing distractions with a user-friendly interface. Equipped with essential equations, it provides instant design feedback. Red font warnings indicate design limitations, ensuring practical results. Constraints include Gain (11.8-21.6 dBd) and Boom Length (2.2-39 wavelengths), with additional frequency-dependent restrictions noted in input fields.

The W5GI Mystery Antenna is a versatile multi-band wire antenna designed for amateur radio operators. It covers frequencies from 80 meters to 6 meters, making it suitable for a wide range of operating conditions. The antenna features a low feed point impedance, allowing for easy matching with most radios, whether or not an antenna tuner is used. Its construction is straightforward, requiring only two vertical supports approximately 130 feet apart, making it ideal for hams without towers. Users have reported excellent performance, particularly on the 20-meter band, where it outperforms similar designs like the G5RV. This antenna is unique in its design, incorporating three half waves in-phase on 20 meters, resulting in a six-lobe radiation pattern. Despite its effective performance, the antenna is challenging to model, which adds to its mystique. The W5GI Mystery Antenna has gained popularity among amateur radio enthusiasts worldwide, with many users praising its ease of construction and effectiveness. Whether you're a beginner or an experienced operator, this antenna offers a fun and rewarding project that can enhance your HF capabilities.

HamScope v1.56, released on 2007-03-20, functions as a multi-mode communications interface for amateur radio, supporting digital modes such as PSK31 (BPSK and QPSK), RTTY, ASCII, MFSK16, PACKET, and CW. The software integrates with external engines like _MMTTY_ for RTTY/ASCII and AGWPE for PACKET operation. It features a panoramic waterfall display, 42 user-programmable macro buttons, and user-definable function key mappings, providing operators with enhanced control during digital mode operations. The program includes a radio control interface compatible with several ICOM, TenTec, Kenwood, and Yaesu transceivers, enabling direct rig control. HamScope also establishes data links with various logging and radio control applications, including LOGic 7/8, DXbase 2004, RYLogit, and TRX-Manager, facilitating seamless data exchange and logging. A DDE server is available for custom connections. Designed for Windows 98 and NT, HamScope requires a 133 MHz Pentium-class machine and 16-bit SVGA color. While not officially supported, users have reported functionality on Windows 95, ME, XP, and 2000, though some issues with window settings or the MMTTY engine may occur. The software is distributed as a single executable file, with separate downloads required for MMTTY and AGWPE engines.

Demonstrates the construction of a **multi-band HF mobile antenna** utilizing a modified CB whip antenna base. The resource details the process of stripping a commercial CB whip, winding a new helical coil with 0.7mm insulated copper wire, and identifying tapping points for various HF bands. It emphasizes the importance of a rugged, slim design for mobile operation, discussing mechanical length, power handling (up to 200 watts), and coil diameter considerations. The article includes a graphic illustrating the antenna's operational principle, where sections of the helical coil are shorted from bottom to top to maintain efficiency and high Q. The resource presents a practical approach to achieving **band switching** without an external tuner, by manually adjusting tapping points on the coil. It provides a table with reference lengths in centimeters from the feedpoint for 7 MHz (40m) through 28.7 MHz (10m), including WARC bands. The author details mounting techniques, suggesting a Diamond bracket for secure attachment to a vehicle trunk, and stresses the critical role of proper grounding for optimal performance. The design allows for operation on 75m and 80m bands by adding a 110mm steel whip.

This resource provides a detailed guide on constructing a J-pole antenna specifically for the 2 meter band, which is popular among amateur radio operators. The article outlines the materials needed, including various sizes of aluminum pipes and PVC, as well as the tools required for assembly. It emphasizes the simplicity and effectiveness of the J-pole design, making it an ideal choice for newcomers to amateur radio. The instructions are straightforward, allowing users to build the antenna in less than an hour, and include tips for tuning the antenna for optimal performance. In addition to the construction details, the resource includes practical advice on the assembly process, such as how to cut and join the pipes, as well as how to mount the SO239 connector. The author shares personal experiences and insights on achieving a low standing wave ratio (S.W.R.) and suggests modifications for creating bi-band or tri-band J-pole antennas. This comprehensive guide is enriched with photographs that illustrate the construction steps, making it easier for users to follow along and successfully build their own J-pole antenna.

A 10-20 meters coverage delta loop antenna. After relocating, DL2HCB designed a multiband loop antenna to cover 10-20m with an open-wire feed for impedance matching and compact installation. Inspired by the mini-X-Q design, a modified 10m delta-loop was built, enhanced with a 1/4 wave shorted stub for 28 MHz using 450-ohm ladder line. The antenna delivers east-west broadside radiation and performs as a closed loop on other bands. Operational tests yielded strong European signals and successful DX contacts, including a 20m QRP QSO with FY/DJ0PJ.

CwGet v2.55 is a software application for amateur radio operators designed to decode Morse code (CW) signals into text using a standard computer sound card, eliminating the need for specialized hardware. The program features a customizable interface with a spectrum display for visualizing signal frequencies and peaks, an oscillogram for monitoring signal presence and setting detection thresholds, and a received symbols window for displaying decoded text. Key functionalities include Automatic Frequency Control (AFC) to lock onto signals, adjustable FIR and IIR filters for noise reduction, and a burst filter to mitigate short noise impulses. It also supports automatic CW speed detection, multiple character sets, and the ability to record and replay received audio. Integration with logging software like AALog is facilitated through double-click word transfer, and transceiver frequency control is possible via the Omni-Rig interface, allowing for automatic tuning of the radio's VFO or RIT. The multi-channel decoder feature can simultaneously decode up to five strong signals within a 1600 Hz bandwidth, displayed in a separate Multi-RX Window with an adjustable squelch. CwGet also offers the capability to decode signals from pre-recorded WAVE files and can function as a narrow-band sound DSP filter for aural decoding. This is a commercial version and it has been tested on latest MS Winows versions.

The G5RV antenna, with an overall length of **31.10m (102ft)**, functions as a 3/2-wave on 20 meters when installed horizontally at 12m (39ft), exhibiting a resonant frequency of 14.150MHz and an approximate resistance of 80 ohms. Its 10.36m (34ft) stub line, designed as a 1/2-wave on 14.150MHz with a 0.97 velocity coefficient, acts as an impedance transformer across other bands, aiming for multiband operation without traps. On 20m and higher frequencies, the G5RV demonstrates improved gain compared to a standard dipole, attributed to the _collinear effect_ from multiple 1/2-waves along the wire. The original design sought a multiband solution for limited spaces, often requiring an Antenna Tuning Unit (ATU) for effective operation across bands like 80, 40, 30, and 20m, particularly with modern solid-state PAs. Variants, such as the F8CI modification, incorporate a 1/4 current balun at the stub line's base for symmetrical-to-asymmetrical transition, known as a _remote balun_. Proper flat-top or inverted-V installation is critical for maintaining symmetry and collinear gain, with inverted-V apex angles below 120° progressively diminishing higher-band performance.

This guide provides step-by-step instructions for constructing a tin can waveguide antenna, commonly known as a cantenna, for enhancing WiFi signal range. The project is budget-friendly, costing under $5, and utilizes easily accessible materials like a food can and basic electronic components. The design is suitable for 802.11b and 802.11g wireless networks, operating within the 2.4 GHz frequency range. To start, gather the necessary parts including an N-Female chassis mount connector, nuts, bolts, and a suitable can. The assembly process involves drilling holes in the can for the connector and mounting the probe. The guide emphasizes the importance of can dimensions and placement for optimal performance, encouraging experimentation for best results. This project is ideal for amateur radio operators and DIY enthusiasts looking to improve their wireless connectivity without significant investment. Safety precautions are advised, as the author does not hold electrical engineering credentials. Users are encouraged to take responsibility for their equipment and ensure proper assembly. With this simple yet effective antenna, users can extend their WiFi coverage and enjoy enhanced connectivity.

Here is the design of a 2.4 GHz antenna that is ideal for amateur satellite communications. This antenna is easy to assemble because the design itself tolerates inaccuracies in the construction without really affecting performance.

The 160/80m coaxial receiving loop antennas are designed to enhance reception on the top bands while minimizing noise. These antennas are particularly beneficial for operators with limited space, as they can be constructed using lightweight materials, making them portable and easy to deploy. The standalone 80m loop has a diameter of approximately four feet, allowing for easy rotation and installation above existing VHF antennas. Over the years, many amateur radio operators have turned to loop antennas as a viable alternative to traditional beverage antennas. The design allows for significant noise reduction, especially when paired with a quality pre-amplifier. Experimentation with various configurations has led to the discovery that diamond-shaped loops provide optimal performance. Users have reported a noticeable improvement in signal quality, making these loops a valuable addition to any low-band DXing setup.

Logger32 is a well-established amateur radio logging program designed primarily for DXers who require a flexible and data-driven logging environment. The software maintains a comprehensive logbook database capable of handling large volumes of QSOs while offering detailed tracking of DXCC entities, awards, and band/mode statistics. One of the core strengths of Logger32 is its DX cluster integration. The program connects to telnet DX clusters and displays spots in real time, with filtering options by band, mode, country, or callsign. The cluster window can automatically highlight needed DXCC entities, band-fills, or new modes based on the operator’s log. Logger32 also provides rig control through CAT interfaces, supporting a wide range of transceivers via serial or USB connections. When properly configured, frequency and mode are automatically captured in the log entry window. The software supports digital mode integration through external applications and can exchange information using standard interfaces. Another important feature is its award tracking system, including DXCC, WAS, IOTA and other common amateur radio awards. The program calculates worked, confirmed, and needed entities with detailed reports. Logger32 supports ADIF import and export, allowing interoperability with other logging systems. It also includes QSL management, with tracking for bureau, direct, and electronic confirmations such as LoTW or eQSL when configured. Overall, Logger32 remains a technically capable logging solution focused on DX tracking, cluster awareness, and detailed statistical analysis of operating activity.

This resource provides comprehensive instructions for constructing a 2 element quad antenna specifically designed for the 10, 12, and 15 meter bands. The antenna features a diamond configuration, which offers improved gain compared to a square configuration. The author shares insights into the materials used, including a square-aluminum boom and bamboo poles, along with construction techniques that ensure durability and optimal performance. This project is ideal for amateur radio enthusiasts looking to create their own antennas at home. In addition to construction details, the author discusses the antenna's performance, noting its effectiveness even at a height of 8 meters. The quad antenna reportedly performs comparably to a 3 element yagi, with excellent SWR readings and strong signal reports from European stations. This project is suitable for beginners and offers a cost-effective solution for those interested in enhancing their amateur radio setup with a homemade antenna.

Author evaluated a custom-built passive AM loop antenna, achieving notable DX reception including KLBJ Austin (230 miles) and WWL New Orleans (700 miles). The antenna operates solely on resonant inductive coupling, enhancing weak signal reception without external amplification. This project illustrates how fundamental RF design—calculating inductance, capacitance, and Q factor—can significantly boost performance of consumer-grade radios. Detailed construction techniques, theoretical background, and optimization strategies for effective loop antenna design are presented for amateur and experimental use.

An effective 10-20m DX antenna for deed restricted lots. The article by K7ZB introduces a simple 10-20m DX antenna suitable for deed-restricted lots. The antenna, a 15' vertical design, facilitated contacts with over 200 countries worldwide. Its design employs a telescopic aluminum tube and radial wires for multi-band operation, requiring an external antenna tuner for optimal performance. The mounting scheme and construction details ensure effectiveness and ease of use.

Dissects the internal components of the popular _Antron 99_ vertical antenna, revealing its unique design elements. The analysis details the construction of the coaxial phasing sections, which contribute to its multi-band performance across 10, 12, 15, and 17 meters. Observations include the use of fiberglass tubing for weather protection and the specific arrangement of conductors within the antenna's structure. The examination highlights the antenna's reliance on a series of coaxial stubs to achieve resonance on multiple HF bands without external tuning. This internal architecture provides insights into how the _Antron 99_ manages impedance matching and radiation patterns for effective DX operation. Further details cover the antenna's base mounting and overall physical dimensions.

SSTV freeware software for Windows by Mako JE3HHT. MMSTV is a free software application designed for transmitting and receiving SSTV (Slow Scan Television) images over HF bands. It allows radio amateurs to share still pictures using sound-card interfaces and a transceiver. The program supports popular SSTV modes (Martin, Scottie, Robot, etc.), real-time RX/TX monitoring, and easy image editing. Its user-friendly interface and reliability make MMSTV a favorite choice among ham operators worldwide. Ideal for showcasing QSL cards, shack photos, or technical diagrams over the ai An excellent SSTV program that requires only a computer with soundcard, no expensive TNC required. Works on all Windows version including Windows XP, Vista and Windows 7.

Sixty-four years of operating experience inform Glynn E. "Buck" Rogers Sr., K4ABT's, insights into the J-Pole antenna, which he describes as a direct descendant of the _Windom_ or _ZEPP_. His first article on the J-Pole appeared in HRC magazine in 1958, and he has since published numerous pieces in publications like CQ Magazine, consistently referring to the J-Pole as a Windom with a folded-back short section forming the parasitic element. He emphasizes that both the Windom and J-Pole are powerful multi-band antennas, performing exceptionally well at harmonics of their fundamental design frequency, and advocates for 50-ohm coaxial cable with a _BALUN_ at the feed-point to avoid RF energy losses. K4ABT details the J-Pole's features, noting its ease of erection, lack of radials, low angle radiation, greater bandwidth, and immunity to terrestrial noise. He highlights its suitability for local nets and distant repeaters, claiming more gain and durability than most ground planes, and its ability to meet stealth antenna requirements. The guide provides specific dimensions for 2-meter (145.000 to 146.000 MHz) and 6-meter (50.500 to 51.500 MHz) J-Pole antennas, including measurements for the long driven element, short tuning stub, and spacing. The construction section illustrates a modified feed technique using an SO-239 chassis-mount coax connector soldered into a copper tee, deviating from the usual hose clamp method. The author also discusses the use of _EMT_ (electrical metallic thin-wall conduit) as an alternative to copper in earlier days. He cautions against building a 75-meter J-Pole due to its impractical length, reinforcing the antenna's optimal application for VHF and UHF bands.

The page provides a project for an indoor wire antenna for the 7 MHz band, based on a design by F6CYV. It aims to help amateur radio operators lacking space to set up an antenna for 40 meters. The author shares their experience using the antenna inside an apartment, noting good reception of European signals and contacts with over 150 countries. The project details the materials and dimensions needed for the antenna, along with tips for optimal performance.

Demonstrates the construction of **magnetic loop antennas**, detailing both multi-turn and single-turn designs. It covers a 30-inch diameter multi-turn loop for 80 meters, based on a February 1996 QST article, and an octagon single-turn loop made from 15mm copper tube with a 4.8-meter circumference, operating from 7 MHz to 14 MHz. The document also presents a smaller 800mm diameter loop for 14 MHz to 28 MHz, emphasizing the importance of high-voltage tuning capacitors. Covers the design and construction of custom **butterfly capacitors** and piston capacitors, including a split stator capacitor with 140 pF capacitance and a 6000 Volt rating, and a butterfly capacitor with 5-65 pF and 7200 Volt rating. It explains why butterfly capacitors are preferred over split stator types for high power applications due to lower losses and direct series connection of rotors, reducing resistive losses from wiper contacts. Material recommendations include clear PVC for plates and brass or stainless steel for non-magnetic hardware. Addresses practical considerations such as feeding the loop with a shielded 1/5 Faraday loop made from RG213 or RG8 coax, achieving VSWR 1.1 across bands, and optimizing its placement 180° from the capacitor. It also discusses mechanical joint resistance, dissimilar metal oxidation prevention using Vaseline, and a simple method for determining radiation angle with a TL-light tube. The guide includes diagrams for rotor, stator, and end plate construction.

Presents _Henry Radio Inc._ as a manufacturer of solid-state RF power amplifiers, detailing their capabilities across HF, VHF, and UHF bands. The company designs and builds custom amplifiers tailored for various applications, including amateur radio, commercial broadcasting, military, scientific, and industrial uses. These amplifiers are manufactured in the USA, emphasizing domestic production. Beyond amplifier manufacturing, the resource highlights Henry Radio's role as a distributor for _Bird RF Test Equipment_, including wattmeters, dummy loads, and attenuators. It also mentions _Tohtsu Coaxial Relays_ and a range of miscellaneous amplifier parts and electronic accessories, providing a broader scope of communication equipment offerings. Additionally, the site describes a trunking two-way radio system operating on the 450-476 MHz band, covering significant portions of Los Angeles and Orange County. This service caters to professional dispatch needs for ambulances, taxis, and other commercial entities, requiring no long-term contracts.

The 144-430 portable j-pole antenna is designed for amateur radio operators seeking a lightweight and efficient solution for VHF and UHF communications. This antenna is particularly useful for portable operations, allowing hams to set up quickly in various locations while maintaining excellent performance. Constructed from readily available materials, it can be easily homebrewed, making it an ideal project for both beginners and experienced operators alike. The j-pole design offers a simple yet effective configuration that provides a good match across the 144 MHz and 430 MHz bands. Its vertical polarization and omnidirectional radiation pattern make it suitable for local communications and simplex operations. This antenna can be deployed in various environments, whether in the field or at home, and is well-suited for mobile applications. With proper construction techniques, operators can achieve optimal performance, enhancing their ability to make contacts during contests or casual QSOs.

The JACK Audio Connection Kit provides a robust, cross-platform solution for routing audio and MIDI data between various software applications with minimal latency. It addresses the common challenge of directing the output of one program, such as a digital mode decoder or SDR application, into the input of another, like a logging program or audio recorder. Jack audio is a multi platform application, runs on Linux, Windows and MacOS. This virtual audio cable functionality allows for complex signal flows, enabling users to simultaneously send audio from a single source to multiple destinations and even loop it back for recording or further processing within the same or different applications. For amateur radio operators, JACK facilitates advanced configurations for digital modes, contesting, and signal analysis. It supports intricate setups where a single radio's audio output can feed multiple decoders, spectrum analyzers, or recording utilities concurrently. The API is designed for real-time performance, crucial for applications requiring precise timing and minimal delay in audio processing.

Operating a handheld transceiver (HT) while bicycle mobile presents a significant challenge due to the lack of an effective ground plane on a bicycle frame. This project addresses that issue by providing construction details for a 2-meter antenna, specifically adapting the _ARRL Hints and Kinks_ design by Charlie Lofgren, W6JJZ, known as the "Bike 'n Hike Special." The antenna is designed to function efficiently on the 144 MHz band, offering a practical solution for portable VHF communication. The design emphasizes simplicity and portability, crucial for mobile operations where space and weight are at a premium. It details the necessary components and assembly steps, allowing amateurs to build a functional antenna that overcomes the inherent limitations of a bicycle as a radio platform. The original concept was published in the ARRL's well-regarded collection of practical amateur radio solutions. This antenna project enables bicycle mobile operators to achieve improved signal performance compared to a stock HT rubber duck, facilitating more reliable contacts while on the move. It represents a straightforward approach to enhancing VHF communications for active hams who combine cycling with their radio hobby.

For radio amateurs considering homebrew antenna projects, this resource details several designs from WE6W, an experienced operator. It covers the construction and characteristics of a _160 Meter QRP Loop Antenna_ optimized for high voltage, along with standard and folded variations of the double bazooka antenna. The site also presents a unique Field Day antenna design and instructions for building a Sterba Curtain, a directional array known for its gain. Each design includes practical insights from the author's building experience. The author provides comparative data, such as the performance of a standard bazooka against a traditional dipole, offering real-world context for antenna selection. The Sterba Curtain section includes notes on its beamwidth and gain, crucial parameters for directional operation. These designs are suitable for hams looking to experiment with cost-effective, high-performance antennas for various bands and operating scenarios, from QRP on 160m to directional DXing with a Sterba Curtain, which can offer significant forward gain, often exceeding **10 dB**.

The Pfeiffer Maltese Quad Antenna System presents a unique approach to traditional quad antennas by utilizing a linear loading technique. This method effectively reduces the overall size of the antenna while maintaining its performance capabilities. Designed by Andrew Pfeiffer, the antenna's configuration resembles a Maltese cross, which not only enhances its structural integrity but also allows it to withstand challenging environmental conditions. This system is adaptable, offering various configurations from a 4-spreader Maltese Quad to a 16-spreader Maltese Quadruple-Cross, making it suitable for operators looking to optimize their setup without sacrificing efficiency. This antenna system is particularly versatile, covering multiple bands including 40, 20, 17, 12, and 10 meters. The design focuses on minimizing the physical footprint while ensuring effective signal transmission and reception. Amateur radio operators can benefit from the detailed plans available in the accompanying PDF, which outlines the construction process and specifications. Whether you're a seasoned DXer or a newcomer to the hobby, the Pfeiffer Maltese Quad Antenna System offers a practical solution for enhancing your station's capabilities.

Constructing a 2-meter 5/4 wave antenna, N1HFX details a design fully enclosed within 3/4-inch PVC tubing, addressing the significant velocity factor of PVC which necessitates a 19% reduction in physical length. The design incorporates a specific matching system using 300-ohm TV twin lead to counteract the highly inductive impedance component inherent in a 5/4 wave radiator. Key components include #18 stranded insulated wire for the radiating element, RG58/U coax, a PL259 connector, and a hardwood dowel for internal support, all carefully dimensioned for optimal performance within the PVC housing. The article provides precise cutting lengths for the twin lead and #18 wire, with the overall assembly measuring 77 3/4 inches, reflecting an approximate velocity factor of 0.81. Tuning instructions emphasize taking SWR readings with the antenna assembly inside the PVC, adjusting the #18 wire and twin lead in small increments to achieve a low SWR across the 2-meter band. The prototype antenna achieved SWR readings below 1.2:1 across the entire band, and N1HFX suggests an estimated 6 dB gain when properly mounted, offering a cost-effective alternative to commercial antennas.

The page describes a Double-L antenna for 80 and 160 meters bands, designed by Don Toman, K2KQ, with a simple, effective, and ground system-free design. The antenna is a center-fed half-wave vertical with horizontal top and bottom sections, providing good performance without the need for an elaborate ground system.

A 1/4 wavelength resonator design for dual-band VHF/UHF operation is presented, focusing on a robust mobile antenna construction. The design prioritizes stability against environmental influences over raw gain, making it suitable for general use rather than marginal signal areas. It details the antenna's two sections: a UHF-resonant lower conductor and an upper coil functioning as an RF choke for UHF and an inductance enhancer for VHF, forming a resonant circuit. Detailed mechanical structure and material considerations are provided, including the use of a PL-259 plug base, 2mm copper rod, and PVC faucet tube for the coil form. The guide outlines a precise construction procedure, from soldering the copper rod to the PL-259 to winding the 22 SWG laminated wire for the VHF section. Tuning involves careful cutting of the UHF section and adjusting the coil length and pitch for VHF, using a reflectometer and temporary ground planes. Furthermore, the resource describes converting the mobile antenna for base station application by constructing a dual-band ground plane system. This involves using electrical conduit, EMT connectors, SO-239 sockets, and a 4-inch round-pan with threaded stainless steel rods as ground elements. Practical test results indicate optimal lengths of **70mm** for UHF and **350mm** for VHF ground elements, with a recommendation to cut rods with _30mm_ extra length for fine-tuning.

The HB9ABX mobile HF antenna, developed by _Felix Meyer_, offers a high-performance alternative to commercial mobile antennas for 80 through 10 meters. Constructed from fiberglass rods and enamelled copper wire, this design incorporates a loading coil with multiple taps, allowing for band-specific tuning. The article provides detailed instructions for winding the coil, connecting the antenna elements, and integrating it with a vehicle's chassis ground. Field tests conducted at 100W consistently showed the HB9ABX antenna outperforming a HUSTLER mobile antenna by up to **10 dB** (1 S-point) and a YAESU ATAS-100/120 by **18 dB** (2-4 S-points) across distances from 5 km to 1000 km. The design emphasizes a robust ground connection and the use of an antenna tuner, such as an _MFJ-901B_, for optimal SWR on all bands, particularly 40 and 80 meters. Initial adjustment involves setting whip length and coil tap positions to achieve resonance without a tuner, followed by fine-tuning with the tuner during operation. Specific measurements are provided for checking resonance on 21.0 MHz and 14.2 MHz, with precise turn counts for the lower (79 turns) and upper (120 turns) antenna sections. Safety precautions for handling fiberglass dust are also highlighted.

Details the construction of a J-vertical antenna specifically for the 10-meter band, offering a practical alternative to a _Slim Jim_ design for 28 MHz. The resource outlines the use of aluminum tubing for the half-wave vertical section and coaxial cable for the quarter-wave matching section, providing specific calculations for element lengths based on frequency and coaxial cable velocity factor. It contrasts the performance of the J-vertical with center-fed dipoles and end-fed verticals, noting superior results in previous comparisons. The article further presents a more recent iteration of the J-vertical, constructed using a fiberglass pole and insulated wire, with updated dimensions for 28.8 MHz. It includes practical advice on weatherproofing connections and securing the antenna for durability against adverse conditions, referencing the survival of an original _J Vertical_ during 110 MPH winds in 1987. The SWR performance is reported as 1.1:1 at 28.6 MHz, maintaining below 1.5:1 across 28.3 to 29 MHz.

The boomless quad antenna is a unique design that offers versatility for amateur radio operators. This antenna consists of two half-wave dipoles arranged in a square or circular shape, allowing for both vertical and horizontal polarization depending on the feed point. The design facilitates easy installation and rotation, making it suitable for various operating conditions. The construction utilizes strong materials, such as bamboo, and incorporates waterproofing techniques to enhance durability. This project outlines the necessary dimensions and materials, including copper wire and insulators, to successfully build the antenna. It emphasizes the importance of tuning each radiator element for optimal performance. The boomless quad is particularly effective across multiple HF bands, including 14 MHz, 21 MHz, and 28 MHz. By following the detailed instructions, operators can achieve a reliable and efficient antenna setup that enhances their DXing and contesting capabilities.

DXKeeper is a robust, freeware logging application designed for amateur radio operators, providing extensive capabilities for managing two-way radio contacts. It records and organizes QSO data, integrates with various callbook CD-ROMs like _HamCall_ and QRZ.com for automatic data population, and supports real-time logging from digital mode software such as MMTTY and MixW. The software runs on Windows NT through 8, supporting both 32-bit and 64-bit systems, and is a core component of the DXLab Suite. This application offers detailed tracking for numerous awards, including DXCC, WAZ, WAS, and IOTA, highlighting needed entities and automating the QSL process. It generates QSL cards and labels, addresses envelopes, and facilitates uploading and downloading of QSO confirmations with eQSL.cc and Logbook of the World (LotW). DXKeeper also interoperates seamlessly with other DXLab Suite members like Commander for transceiver control and SpotCollector for DX spot aggregation, significantly streamlining contest and DXing operations by providing a unified interface for logging and station management, including over **40** supported awards and **3** major online QSL services.

A 9 dB gain 70cm collinear antenna construction is detailed, utilizing eight half-wavelength sections of _RG58/U_ coaxial cable. The design incorporates specific calculations for velocity factor (0.66 for RG58/U) to determine precise element lengths, such as 223mm for a half-wavelength at 444 MHz. A quarter-wave radiating element of #16 solid wire, 169mm long, is added to the top, and a 160mm aluminum tube acts as a quarter-wave counterpoise at the feed point. RF choke baluns, constructed from three _FT50-43_ toroids, are positioned a half-wavelength from the feed point to mitigate common mode current. Assembly involves soldering the coax sections in series, followed by SWR testing during construction and final mounting within a ¾-inch PVC pipe. The article suggests using four half-wave elements for a shorter antenna, noting a potential slight increase in SWR, which can be mitigated with quarter-wave ground radials. The design principles and formulas are scalable for other VHF/UHF bands like 6m, 2m, or 1¼m, providing a versatile homebrew solution for enhanced gain.

The Cubical Quad antenna is a popular choice among amateur radio operators due to its robust design and excellent performance characteristics. This resource provides essential scaling formulas that help determine the lengths of the antenna elements and the necessary gamma match values for various frequencies. The design is adaptable, allowing operators to optimize for gain or front-to-back ratio by adjusting the spacing between elements. The accompanying Excel files facilitate precise calculations, making it easier for both beginners and experienced hams to construct their own Cubical Quad antennas. In addition to the design formulas, the resource includes practical insights from the author, who has successfully built and utilized these antennas in various field events. The document outlines the tuning process for achieving minimum VSWR, ensuring optimal performance. With detailed illustrations and performance data, this guide serves as a comprehensive reference for anyone looking to delve into Cubical Quad antenna construction and optimization, enhancing their amateur radio experience.

The **DF9CY Three-Element Antenna for 28 MHz** details the modification of a commercial PAN International CB antenna to optimize its performance for the 10-meter amateur radio band. This resource provides specific design parameters, including a design frequency of 28.300 MHz, a usable bandwidth of 600 kHz, and a return loss better than 20 dB centered at 28.270 MHz. It also specifies a gain exceeding 7.5 dBi and a front/back ratio greater than 20 dB. The feeding mechanism utilizes a **gamma match**, with setup instructions provided for its positioning. Modifications involved shortening each element's end by 40 mm, a straightforward process due to existing screw holes. The author also recommends replacing the original screws with V2A stainless steel hardware to prevent oxidation and upgrading the SO239 connector to an N-connector for improved reliability. EZNEC simulation files are available, showing azimuth and elevation diagrams with good front-to-back ratio and around 10 dB vertical attenuation. The antenna has been in service since October 1998, demonstrating good performance with 90 watts and even 750 watts, facilitating contacts with all continents from a modest 9-meter height.

Monitoring shortwave broadcast stations effectively requires accurate schedule information to identify transmissions. This online utility offers a straightforward, graphical interface designed to search for and display current shortwave radio broadcasting schedules. Users can precisely filter results by frequency, specific language, broadcaster, time of day, and even by shortwave band, which simplifies the process of pinpointing desired content. The database, last updated on March 26, 2023, details station callsigns (e.g., BBC), start and end times in UTC, days of the week, broadcast language, transmitter power in kilowatts, and azimuth. Crucially, it includes the precise geographical coordinates of transmitter sites, such as Woofferton in the UK or Al Seela in Oman. This data is invaluable for predicting signal paths and optimizing antenna direction for improved reception, a key consideration for serious SWLs. For instance, a search for BBC English broadcasts at 21:04 GMT quickly reveals multiple active frequencies like 17780 kHz from Woofferton, offering a clear overview of current transmissions. The tool processes queries rapidly, returning results within seconds, demonstrating its efficiency for broadcast listening enthusiasts seeking timely information.

The RXO Unitenna, a vertical wideband antenna, offers operation across the 7-21 MHz spectrum, covering the 40, 30, 20, 17, and 15-meter amateur bands. This design focuses on achieving a low SWR across a broad frequency range, making it suitable for general HF operation without requiring an external antenna tuner for minor SWR variations. The antenna utilizes a unique loading coil and matching network to maintain efficient radiation characteristics across its operational bandwidth. Construction details within the PDF document include specific dimensions for the radiating element and the counterpoise system, which is critical for vertical antenna performance. The design incorporates readily available materials, simplifying the build process for radio amateurs. Performance graphs illustrate the SWR characteristics across the 7 MHz to 21 MHz range, demonstrating the antenna's wideband capabilities. The document also provides guidance on feedline connection and grounding considerations for optimal field deployment. This vertical antenna configuration is particularly useful for hams with limited space, offering a compact footprint compared to horizontal wire antennas.

The SK6AW DX-Cluster provided a web-based interface for real-time DX spotting, featuring a flexible and configurable environment for amateur radio operators. It supported various display _skins_, allowed users to send spots, and integrated _e-mail and push notifications_ for alerts. The platform was designed to offer a comprehensive spotting experience, enabling users to track propagation and DX activity across multiple bands, similar to traditional _telnet clusters_ but with a modern web interface. This service, formerly hosted on dedicated servers, transitioned to a shared hosting platform before its scheduled shutdown on December 13, 2025. The decision to discontinue the cluster was attributed to a lack of resources for updating it to contemporary standards. Users seeking similar functionality are directed to alternative DX spotting services such as _dxsummit.fi_ or _dxheat_, which continue to provide real-time DX information and related features for the amateur radio community.

Optimizing the impedance transformation and common-mode current suppression in antenna systems often involves selecting an appropriate balun. This project presents a **hybrid balun** design, combining characteristics of both voltage and current baluns to achieve superior performance, particularly when used with an antenna tuner. The design addresses issues like **common-mode current** on the feedline, which can distort the antenna's radiation pattern and introduce RFI in the shack. The construction details include winding techniques for the toroid core, component selection, and practical considerations for integration into an existing antenna system. Performance comparisons are drawn against conventional balun types, highlighting the hybrid balun's effectiveness across the HF bands. The resource provides insights into the current distribution and impedance matching properties, crucial for efficient power transfer and reduced SWR.

Determining the actual need for an antenna tuner often hinges on the specific antenna and feed line configuration in use. While many hams believe a tuner is always essential, its primary role is to present a 50-ohm impedance to the transceiver, not to "tune" the antenna itself. For instance, a resonant dipole fed with _coaxial cable_ at its design frequency typically requires no tuner, as the feed line impedance closely matches the radio's output. However, operating a non-resonant antenna, or using a resonant antenna on multiple bands, frequently necessitates a tuner to manage high Standing Wave Ratio (SWR) on the feed line. The article clarifies that a tuner placed at the transceiver only matches the radio to the feed line, not the antenna to the feed line. For maximum efficiency with a non-resonant antenna, an _automatic antenna tuner_ (ATU) or a remote tuner placed at the antenna feed point is often more effective, minimizing losses in the feed line. The discussion also touches on the practical implications of SWR, noting that modern transceivers often fold back power at high SWR, making a tuner a practical necessity to achieve full output power, even if the antenna itself is not perfectly matched.

The project details a DIY SWR/Wattmeter designed around an _Arduino Uno_ shield, providing capabilities to measure RF power from 2 to **200 watts** and Standing Wave Ratio (SWR) for HF amateur radio bands. This construction features a compact design, integrating the measurement circuitry directly onto a custom PCB that interfaces with the Arduino Uno microcontroller. Key components include a directional coupler for sensing forward and reflected power, precision rectifiers, and analog-to-digital conversion for processing RF signals. The Arduino firmware handles calibration, calculations, and displays the results on an integrated LCD, offering real-time feedback on antenna system performance. The design prioritizes simplicity for homebrewers. Performance specifications indicate accurate readings within the **2-200W** power range, suitable for typical QRP to medium-power HF operations. The project provides schematics and a basic overview of the software logic.

Two well performing 50 MHz antennas designed with W7EL EZNEC along to many other antenna projects and related articles

NGC is now distributor for COMET and MALDOL brand antenna products designed, manufactured in Japan. Distributor of DAIWA brand RF SWR/power meters and switching power supplies, antennas, test equipment, antenna analyzers and more

The HB9ABX RoomCap antenna document details the construction and performance characteristics of a compact HF antenna design. It presents a series of comparative field tests conducted between July and September 2005, evaluating the HB9ABX antenna against established designs like the Microvert MV-500, Cushcraft R5/R7000 verticals, and a 5-element DJ2UT Yagi beam. Specific test scenarios include mobile installations, rooftop deployments, and comparisons on 20m, 40m, 80m, and 160m bands, with signal reports from various European and DX stations. The resource emphasizes the antenna's small physical footprint and its claimed efficiency across multiple HF bands. Test results consistently show the HB9ABX antenna performing comparably to, and often outperforming, larger reference antennas in terms of received signal strength, with reported differences of 1 to 2 S-points (6-12 dB) in many contacts. Notably, a 20m DX test on July 26, 2005, indicated the 1.3m HB9ABX radiator yielded 2-3 S-points stronger signals than an R7000 vertical for US DX stations. An August 12, 2005, test on 40m highlighted the HB9ABX's superior signal-to-noise ratio in urban QRM, demonstrating 10-18 dB better performance than an R7000. The document includes specific callsigns, signal reports, and QTHs for each comparison, providing empirical data for the antenna's performance claims.

Over 25,000 amplifiers and sub-assemblies were produced by Angle Linear for the communications industry over a 40-year period. The company specialized in **high-linearity RF products**, focusing on preamplifiers, bandpass filters, and receiver multicouplers. Specific product lines included PHEMT and GaAs FET preamplifiers, offering both quadrature and single-ended configurations for various signal levels. The offerings encompassed coaxial and combline bandpass filters, along with integrated filter-preamplifier assemblies. The company also provided custom RF assemblies, addressing applications such as MRI preamplifiers, passive radar, and EME (moon bounce). Their product range covered VHF and UHF frequencies, including specific designs for 2m, 70cm, and 23cm bands, often featuring high IP3 performance. Technical documentation, such as filtering application notes and duplexer theory, was also associated with their product offerings.

This Vertical antenna design by David Reid for lower bands focuses on achieving effective DX communication by optimizing the antenna low-angle radiation for long-distance contacts. The design incorporates techniques like linear loading and capacity hats to reduce the antenna's height while maintaining performance, especially on 40m and 80m bands. Building a solid ground plane and using quality materials ensure efficiency and durability. Although vertical antennas can be complex to build, this project simplifies the process, making it accessible for ham operators seeking strong, reliable signals.

Details the construction and optimization of antenna systems for amateur radio satellite operations, focusing on practical, homebrew solutions for VHF/UHF bands. It covers building _groundplane antennas_ from salvaged materials, recycling old beam antennas into new configurations like a 2-meter crossed yagi, and constructing a 10-meter horizontal delta loop. The resource also explains antenna matching techniques, including folded dipole driven elements and quarter-wave transformers, along with the importance of accurate SWR measurements and minimizing coax loss. Demonstrates how to achieve a **1:1 SWR** by carefully trimming elements and adjusting radial angles on groundplane antennas. It provides insights into selecting appropriate coax and connectors, highlighting the benefits of Belden 9913 for low loss and the proper installation of _N-connectors_. The article also addresses RFI mitigation from computer birdies and presents a design for a silent triac antenna control circuit, offering practical solutions for common satellite station challenges.

Galaxy DX 47HP and DX 99V2 models are highlighted, showcasing the manufacturer's current offerings in both amateur and Citizens Band radio transceivers. The site details several amateur models, including the DX 29HP, DX 44HP, DX 55HP, DX 98VHP, DX 33HP2, and DX 94HP, catering to different operational needs and power levels. For CB operators, a range of models like the DX 2547, DX 979, and DX 929 are presented, with specific features such as _StarLite_ front panel lighting for low-light conditions, as seen on the DX 929 and DX 979. The DX 979 is noted for its compact form factor and SSB capability, making it suitable for installations where space is a constraint. Conversely, larger models like the DX 939, DX 949, and DX 959 are available for those with more room, offering features such as blue lighting and integrated frequency counters. The DX 939, for instance, combines aesthetic appeal with functional design, providing clear readouts and robust audio performance. A downloadable CB radio shopping guide is also offered, enabling users to compare Galaxy's product specifications against other radios on the market, facilitating informed purchasing decisions.

Orbitron, a cardware application, provides robust satellite tracking capabilities for radio amateurs and visual observers alike. It leverages NORAD SGP4/SDP4 prediction models to accurately display satellite positions in real-time or simulation, accommodating up to 20,000 objects loaded from _TLE files_. The software includes an advanced search engine for satellite passes and _Iridium flares_, offering printable results for planning observations or QSO attempts. Sebastian Stoff's creation supports various visualization options, including a 'Nightlife' dark color scheme for nocturnal use, and integrates a database of cities and satellite frequencies. Users can synchronize their PC clock via NTP and update TLE data over HTTP, with ZIP support. The application also features rotor and radio control capabilities, either built-in or through user-defined drivers, which is particularly useful for automating antenna pointing during satellite passes. Its interface is designed for ease of use, making satellite tracking accessible even for beginners. First released in 2005, Orbitron 3.71 runs on Windows 9x/Me/2k/XP/2k3/Vista and can operate on Linux via _Wine emulation_, requiring minimal system resources. The software's precision relies on periodic TLE updates, especially for low-Earth orbit objects, to account for orbital decay and maneuvers by satellites like the ISS or Soyuz.