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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.

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.

The web page provides detailed information on a portable 10/20/40 meter vertical antenna designed for mobile operations, including modifications for 20 and 40 meters. It includes images and descriptions of the antenna setup in a car. The content is useful for amateur radio operators looking to enhance their mobile communication capabilities.

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.

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.

The Super Loop Antenna page, designed by Jim W4FTU, provides detailed information on the RadioWorks \'Superloop III\' antenna as an alternative for operators with limited space. The page discusses the physical variations of the antenna, including dimensions and materials used, as well as its electrical characteristics such as the 30\' ladder line. The content is useful for amateur radio operators looking for antenna options for the 80 and 40 meter bands, especially those with small lots or zoning restrictions. The page is well-organized and informative, making it a valuable resource for antenna enthusiasts.

Cubic quad antennas are renowned for their high gain, excellent front-to-back ratios, and low angles of radiation, making them a popular choice among amateur radio operators. This resource provides detailed designs for constructing cubic quads optimized for 2, 6, 10, 12, and 15 meter bands. The lightweight structure can be easily built using fiberglass tubes and central hubs, allowing for portability and ease of assembly. The article discusses the specific dimensions and configurations required for both HF and VHF applications, emphasizing the importance of proper spreader lengths and boom dimensions. It also highlights the challenges of assembling larger cubic quads in limited spaces, offering practical solutions for hams with smaller backyards. With a focus on multi-band operation, this guide serves as a valuable resource for both novice and experienced operators looking to enhance their antenna systems.

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.

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.

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.

A simple design of a 9 elem. yagi antenna for 2 meters band

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.

The **Extended Double Zepp** (EDZ) antenna, a simple wire design, is presented as a means to achieve 3-4 dB of gain on 10 meters, with an overall length of just 43 feet. This resource, authored by WB3HUZ, details several gain antennas suitable for the 29 MHz AM segment, all modeled using EZNEC software at 30 feet above ground. Other designs include a compact rectangular loop, offering more gain than the EDZ and a lower take-off angle, and the **Lazy H**, a bidirectional antenna providing 6 dB gain, which is also workable on 20, 17, 15, and 12 meters. The Bisquare, a diamond-shaped open-top loop, is also featured, providing approximately 4 dB gain and requiring only a single support. These designs are primarily fed with ladder line or open-wire line to simplify matching, though a coax feed option for the EDZ is shown for 10-meter-only operation. The Lazy H, for instance, requires about 16 feet of open-wire line for its half-wavelength elements spaced a half-wavelength apart. An enhanced EDZ Lazy H variant is also discussed, achieving an additional 1-2 dB gain by extending element length to 1.28 wavelengths and increasing spacing to 0.64-0.75 wavelengths. The Bisquare, while primarily a 10-meter antenna, can be adapted for 20 meters by closing the top connection.

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.

This PDF article from April 2001 QST details the construction of the "NJQRP Squirt," a reduced-size 80-meter inverted-V dipole antenna. The resource provides a general construction sketch, a photograph of the assembled antenna, and specific dimensions for PC-board insulators. The antenna consists of two wire legs, each approximately **34 feet long**, separated by 90 degrees, fed at the center. It is designed for operation on 80 meters (3.5-4.0 MHz) as a quarter-wavelength antenna, requiring a low-loss feedline and an external antenna tuner due to its non-resonant feedpoint impedance. Construction utilizes readily available materials, including 1/16-inch glass-epoxy PC board for end and center insulators, and #20 or #22 insulated hookup wire for the elements. The feedline specified is 300-ohm TV flat ribbon line, with a note on potential trimming for tuner compatibility. N2CX reports the antenna's center should be elevated to at least **20 feet**, with ends no lower than seven feet above ground, resulting in a ground footprint of approximately 50 feet wide. The design prioritizes NVIS propagation for local 80-meter contacts. DXZone Focus: PDF Article | 80m Inverted-V Dipole | Construction Notes | 34 ft element length

Great first time J-pole project. Covers most of the basics. This small and thin design also makes it good for several stealth applications.

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.

This halo antenna for 50 MHz is made with a true Gamma Section this time and is fashioned from aluminum

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.

Build your mobile antenna which outperforms Hustler by 10db and ATAS-100 by 18db. From 80 to 10m. The HB9ABX mobile HF antenna, designed for 10 to 80 meters, was developed by Felix Meyer and outperforms commercial antennas like HUSTLER and YAESU ATAS-100/120 in field tests. Made from fiberglass rods and enamelled copper wire, it includes a loading coil with adjustable taps for tuning across bands. Installation requires solid grounding, and adjustments are made via whip length and coil settings. An antenna tuner ensures optimal SWR. Users must handle fiberglass with care due to health risks. This design proved highly effective in South America and Europe.

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.

HF Windom antenna, cover 80, 40, 20 15, and 10 meters, antenna design

This resource provides access to the 59+ software collection, specifically highlighting the **59+ CW** module. The software enables the generation of Morse code signals for transmission through a COM port to a transceiver, or for audio output via a computer speaker, facilitating both keying and listening practice. Users can customize various parameters, including CW speed, tone frequency, dash/dot ratios, and PTT line delay, alongside defining keyboard shortcuts for common QSO fields such as callsign, QTH, name, and RST. The collection also includes the 59+ Logbook, which operates smoothly on Windows XP according to testing notes, though the CW application experienced startup issues on the same OS. The software was originally designed for older Windows operating systems, specifically Windows 95, 98, ME, and 2000. It is noted that the original idealog.net site is no longer active, and development for the 59+ suite appears to be discontinued. Analyzer and converter modules within the collection require registration and do not function in trial mode.

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 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.

This is the antenna w3ff designed for his walking portable station. It is a dipole constructed out of the plastic plumbing pipe CPVC. There are telescoping whips at the ends of each side of the dipole, and these whips are adjusted to bring the antenna into resonance on each of five HF Bands 10, 12, 15, 17, and 20 Meters

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

Practical contruction and designing notes of a delta loop for the 40 meters band

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.

Presents a practical design for a **crossed-dipole turnstile antenna** specifically engineered for 2-meter Amateur Radio Direction Finding (ARDF) events. The author, WB6RDV, details a robust, omnidirectional, horizontally-polarized antenna, addressing the international ARDF rules requiring such characteristics at a height of two to three meters above ground. This contrasts with the vertical polarization often used in Southern California, highlighting the design's adherence to specific event requirements. The electrical design employs a classic crossed-dipole with a 75-ohm phasing section, resulting in a slight impedance mismatch and an SWR of approximately 1.3:1 with a 50-ohm feedline. Construction utilizes readily available and inexpensive PVC plumbing components and 1/8-inch bronze welding rod for elements. The guide provides step-by-step instructions for mechanical assembly, including drilling element holes at precise 90-degree spacing and preparing the RG-179 matching section. WB6RDV shares insights from his own build experience, discussing the use of plated brass versus aluminum spacers for element attachment and the effectiveness of crimping as an alternative to soldering. The document also covers final assembly, including the integration of ferrite beads as a choke balun and options for weatherproofing and alternative mounting configurations, emphasizing the adaptability of the design for other VHF bands through scaling.

Design of a preamplifier for 144 MHz with 1 dB NF and 23 dB gain using BF981. This amplifier is using a low cost silicon MOSFET (BF981 from Philips) to give more than 20 dB gain with around 1 dB noise figure on 2 meter.

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.

Presents the KE4UYP linear-loaded vertical antenna design, which introduces very little loss on 80 or 160 meters, achieving an overall radiation efficiency of 80% to 85%. This design addresses common pitfalls of traditional base-fed verticals by placing the majority of the current at the top of the antenna, eliminating the heavy reliance on extensive ground radial systems. The author's initial 10-meter model, only three feet tall, yielded 5/9 signal reports to Anchorage, AK, and Europe, confirming its effectiveness. The antenna incorporates both vertically and horizontally polarized radiators, with a 1/4 wavelength horizontal counterpoise located at the feed-point, near the top, to create an almost totally omnidirectional pattern with high wave angle horizontally polarized radiation. This dual polarization ensures even illumination across all take-off angles, making it effective for both local contacts and **DXing**. The vertical element is linear loaded, adding capacitance reactance and making it longer than the horizontal element to achieve resonance and raise the feed-point impedance to 50 ohms. Fine-tuning the antenna requires careful adjustment, as tower reactance can vary. The article suggests starting with 80 feet for 80m and 170 feet for 160m for the vertical wire, then trimming for resonance. Bandwidth specifications include 300 kHz under 2:1 **SWR** on 80m and 100 kHz on 160m when suspended between trees, or 150 kHz on 80m when side-mounted on a tower.

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.

We often think of the Moxon rectangle as strictly an HF antenna. However, its small size and special far field pattern lend themselves to some VHF applications. So let's see how to adapt the design to 2 meters (as a popular band choice) and also see a few of the uses to which we may effectively put the design.

The 80-meter loop antenna, measuring 86 meters (282 feet) of wire, effectively operates across 8 HF bands from 80 through 10 meters, despite its length being a compromise for specific bands. This design prioritizes a "low enough" SWR across multiple bands, aiming for lower SWR values on higher frequencies due to increased feedline losses. A 200-ohm feedpoint impedance provides a workable SWR on every band, with feedpoint impedances ranging from 100 ohms for lower bands to 300 ohms for higher bands. Radiation patterns for the 80-meter loop, mounted at 15 meters high, show a maximum gain of 7.6 dBi at a 90-degree takeoff angle on 80 meters, and up to 12.9 dBi at a 10-degree takeoff angle on 12 meters. This configuration supports regional contacts on 80 meters and provides good DX performance on higher bands. Practical construction notes emphasize using robust supports like trees, ensuring wire slack with _egg insulators_ for wind resilience, and employing an oversized 2 kW 4:1 _balun_ to safely handle higher SWR conditions, even with 100W transceivers. Feedline losses are minimized using _LMR-400_ coax or ladder line, with power transfer efficiency between 80% and 95%. Antenna simulations were performed using _xnec2c_, and the provided NEC file is compatible with other NEC2 derivatives. The antenna is tunable on 6 of 8 bands with an internal ATU and all 8 bands with an external autotuner like the LDG AT-200 Pro.

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

This is a project to develop an Open Source reference design for a 1500 watt solid state linear amplifier for 10 through 160 meters by K6IF

ZZ Wave Net is a 40 & 80 meter full wave loop designed to fit on a city lot. ZZ Antenna is a folded dipole bent into an inverted V loop

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 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.

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.

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.

Based on a design by JM1SZY for 50 MHz that he developed using YO

This project details three variants of a vertical half-wave antenna design for the 4-meter (70MHz) amateur radio band. The antennas use end-feeding with a parallel-tuned circuit for impedance matching to 50-ohm coaxial cable. The first variant uses suspended flexible wire for portable use, the second employs a fiberglass rod with internal wire for permanent outdoor installation, and the third utilizes aluminum tent poles for quick mobile deployment. Despite the narrow bandwidth of the matching circuit, this suits the narrow 4m FM allocation well. The design offers an effective omnidirectional radiation pattern and can be constructed with readily available materials.

The page provides a detailed guide on building a successful 160 Meter short TX loop antenna, with specific dimensions and tuning instructions. It includes information on the design, construction, and tuning of the antenna, as well as the materials required. The intended audience is amateur radio operators looking to build an effective antenna for the 160 Meter band.