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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.

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.

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.

The page provides detailed plans and pictures of 80m and 160m antennas for both transmission and reception, emphasizing the importance of antenna farm on low bands. It discusses the differences between TX and RX antennas, the significance of signal-to-noise ratio, and the benefits of directional antennae. The author shares personal experiences and recommendations for successful operation on low bands.

Details the construction of a **multiband vertical** antenna, specifically designed for stealth operation in a rented property, covering 80m, 60m, 40m, and 30m. The author, N3OX, leverages a 12m Spiderbeam telescoping fiberglass pole as the primary support, noting its sturdiness compared to typical fishing rods while remaining light enough for quick deployment and takedown. The radiating element is a 14 gauge Flex-Weave wire, attached to the pole's top with a rubber grommet, and fed by 27 bare 18 gauge radials spread across a 40-foot square backyard. N3OX describes the impedance matching solution, opting for custom-built L-networks over a remote tuner to enable fast bandswitching. Using an MFJ-259B and EZNEC modeling, base impedances were measured and component values calculated with G4FGQ's L_TUNER and SOLNOID_3 programs. The 80m coil is wound on a 3.5-inch PVC form, while the 30m, 40m, and 60m coils are air-wound, self-supporting #10 wire. Variable capacitors are incorporated for 40m and 30m shunt elements, with the 60m impedance matched by a series inductor. The project includes a **servo-controlled** homebrew band switch, utilizing a two-pole 12-position ceramic wafer switch for remote operation, addressing the limited 80m bandwidth. The entire matching network is housed in a weather-resistant shelter constructed from lumber and aluminum flashing. N3OX reports good DX results at 100W, estimating the total cost between $150 and $250, depending on existing parts.

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.

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.

Low noise, receive only coax loop antennas for 160 - 10 meters HF bands

The "Mighty-Wide" six-meter dipole antenna, constructed from 300-ohm ribbon cable, features a total radiating element length of 2794 millimeters. It incorporates two shorting links placed 220 millimeters from each end and a 30 picofarad ceramic trimmer capacitor for impedance matching. The 50-ohm coaxial feedline connects 292 millimeters below the trimmer capacitor, eliminating the need for an external antenna tuning unit. This design provides a wide bandwidth from 50.00 to 52.00 MHz, making it suitable for the entire UK six-meter band allocation. Performance comparisons with a traditional coaxial dipole show superior **Standing Wave Ratio** (SWR) across the 50-52 MHz range, maintaining a low SWR without significant variation after initial adjustment at 51.00 MHz. The antenna's lightweight construction makes it ideal for **loft-mounted** or portable applications, and its folded dipole characteristics contribute to its wideband operation. The design is being considered for rescaling to WARC bands (12 and 17 meters) and 10 meters.

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 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.

DX clusters aggregate real-time amateur radio spot data, enabling operators to identify active stations and propagation conditions across various bands and modes. DXWatch offers a web-based interface for this essential operating tool, allowing users to filter spots based on specific criteria such as band, mode, or callsign. The service integrates features like a customizable filter system and an external widget for embedding spot data on other platforms, enhancing its utility for DXers and contesters. Operators can access worldwide spot data, with options to zoom into specific regions like the US, Europe, or the North Atlantic, facilitating targeted DXing efforts. The platform also includes a watchlist feature for registered users, enabling personalized tracking of desired stations or entities. Real-time data on solar flux index (SFI), A-index, and K-index are displayed, providing crucial propagation insights alongside the DX spots.

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.

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.

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.

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.

Amateur radio operators often seek reliable equipment for various modes and bands, from QRP operations to high-power DXing. Historically, Ten-Tec has been a notable manufacturer in the amateur radio market, known for its range of products including HF and VHF transceivers, RF amplifiers, and antenna analyzers. Their product line also encompassed specialized items such as QRP transceivers and kits, catering to enthusiasts of low-power communication, and antenna tuners for impedance matching. The company's offerings included test equipment vital for shack setup and maintenance, like SWR meters and RF analyzers, which assist in optimizing antenna systems and ensuring efficient power transfer. Additionally, Ten-Tec provided various accessories and components, supporting both commercial products and homebrew projects. The brand was recognized for its _made in the USA_ manufacturing, appealing to operators who prioritize domestic production. While the website currently displays limited product information, it mentions upcoming items like the _MODEL 594 PHOENIX_ and the _Tune-A-Tenna_, indicating potential future product releases.

Over 200 Telnet DX cluster entries are meticulously cataloged, each providing the cluster's callsign, IP address or hostname, and the specific port for connection. The resource details the geographic location for each cluster, often including grid square information or city/country, which is crucial for operators seeking regional or local spotting networks. For instance, **AB5K** offers both worldwide and USA/Canada-only spot feeds, while **K2LS** explicitly limits spots to USA/Canada/Caribbean Zones 1-8, excluding chat messages. The compilation serves as a practical reference for amateur radio operators who utilize traditional Telnet clients for real-time DX spotting. It presents a raw, unadorned list, prioritizing direct access information over elaborate interfaces. This format allows for quick integration into logging software or terminal programs that support Telnet connections. Distinctively, the resource focuses exclusively on Telnet access, differentiating it from web-based or aggregated cluster services. The sheer volume of listed clusters, spanning continents from Europe and North America to Asia and Oceania, makes it a robust tool for DXers and contesters aiming to monitor propagation and identify rare DX stations across various bands.

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.

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.

Optimizing antenna portability for QRP field operations often involves trade-offs between efficiency and physical footprint. The PAC-12 antenna project addresses this by presenting a **multi-band portable vertical** design, specifically tailored for amateur radio operators who travel frequently and utilize compact QRP transceivers like the Elecraft K1/K2 or Yaesu FT-817. This design emphasizes ease of homebrewing using readily available hardware store components, allowing for customizability and repair in the field. The project details the construction of a sectional aluminum rod base, interchangeable loading coils for various HF bands, and a telescoping whip. Key components include 1/4-inch aluminum rod, PVC risers for coil forms, and a BNC feedpoint insulator. The design prioritizes a breakdown length of 12 inches or less, making it highly packable for travel, while still achieving competitive efficiency, as demonstrated by its first-place finish in the HFPack antenna shootout at Pacificon 2001 against a 1/4-wavelength wire vertical. Comprehensive instructions cover whip preparation, **loading coil construction** with specific dimensions for bands from 40m to 10m (with an untested 80m approximation), base section fabrication, and feedpoint insulator assembly. The resource also includes guidance on radial deployment, threading aluminum rod, and showcases various PAC-12 builds by NJQRP Club members, illustrating its adaptability and widespread adoption among QRP enthusiasts.

K9AY loop antenna installed at PA6Z Contest group. This is a receiving antennas for the low bands (160m, 80m and 40m). Include schematics and info on a building the control box, preamplifier and low-pass filter

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.

Demonstrates a **shunt-feed** matching technique for Hustler mobile HF antennas, specifically the MO-3 mast with RM series resonators, to achieve optimal **SWR** on the 40-meter and 20-meter bands. It details the construction of a loading coil using 20 turns of #12 solid wire, 1.25-inch ID, spread to 5 inches, and provides tap points: 8 turns for 40m and 4 turns for 20m, connecting one end to the feed point and the other to ground. The resource presents specific SWR results, noting a 1:1 match at 7.258 MHz on 40m and 14.275 MHz on 20m, with SWR remaining below 1.5:1 across significant portions of the General phone segments. It highlights a noticeable improvement in both transmit and receive performance compared to a straight antenna setup, emphasizing the practical application of this matching method for mobile installations, particularly on a fender-mounted ball mount.

Optimizing low-band signal performance for contesting and DXing often involves complex antenna systems. This resource presents the FVR Spitfire Array, a "poor man's 4-square" design specifically engineered for the 80-meter and 160-meter bands. The core content is a PowerPoint presentation originally delivered at the 1998 Dayton Hamvention, outlining the design principles and practical considerations for this phased vertical array. The FVR Spitfire Array aims to provide directional gain and improved signal-to-noise ratio on the lower HF bands without the need for a large, rotatable Yagi. The design focuses on achieving effective directivity and pattern control using vertical elements, a common approach for enhancing receive and transmit capabilities on 160m and 80m, where full-sized Yagis are impractical for many stations. The presentation likely covers construction details, phasing networks, and expected performance characteristics. Further information is provided through an additional FAQ document, addressing common questions and offering clarifications on the array's operation and implementation. This supplementary material helps operators understand nuances of the design and troubleshoot potential issues, making the project more accessible for those looking to build or adapt the FVR Spitfire Array for their own station.

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.

a simple, low-cost, trapless short vertical antenna which amazingly works on three HF bands (20, 15 and 10 meters)

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.

Magnetic loops are a compromise antenna and performance will be down on a full size-wire antenna particurlarly on lower HF Bands. This article compare this magnetic loop with a full-sized wire antenna on 80 meters by VK3YE

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.

The article details the construction of a "bug-catcher" style HF mobile antenna, emphasizing its low cost and ease of tuning. It outlines the use of readily available materials such as PVC pipe, #14 house wire for loading and matching coils, and a _RadioShack_ replacement whip antenna. The design allows for operation across 20 through 6 meters, achieving an SWR of **1.5:1** or less on each band segment. The resource provides a comprehensive materials list, step-by-step assembly instructions, and photographs illustrating key construction phases. It explains how to create the coil forms, wind the coils, and secure them with epoxy putty. Crucially, the guide includes a table of suggested coil-tap positions and whip extensions for specific bands, such as 6 turns on the matching coil and 8 turns on the loading coil for 20 meters, facilitating initial tuning. Furthermore, the document discusses installation considerations, including grounding, and offers practical advice for tuning the antenna using an SWR meter. It highlights the antenna's broadband characteristics and its ability to collapse the whip for garage storage, making it a practical solution for mobile HF operation. The author, KM4IE, shares personal experiences with worldwide CW and phone contacts using this antenna.

Quad, Yagi for low bands. Specialist in antennas, supports and moving of medium-large sized radio antennas, professional rotators, masts, towers, and accessories.

This multiband wire antenna it is an off centre fed dipole, with 10 feet of vertical radiator, needs no tuner on 40m, 20m and 10m and works fine on all bands above 40m with a tuner, and even below 40m on 60m, and 80m.

FT2 is an innovative digital mode for amateur radio, developed by IU8LMC with support from ARI Caserta. It utilizes the same codec as FT8 and FT4 but compresses the transmission cycle to just 3.8 seconds, allowing for a complete QSO in as little as 11 seconds. This remarkable speed enables operators to achieve approximately 240 QSOs per hour, making it particularly advantageous for contests and DXpeditions. The FT2 protocol has been rigorously tested on-air, with successful QSOs verified down to -12 dB SNR on both 40m and 80m bands. The mode's efficiency and speed are a significant advancement in digital communications, providing a new tool for amateur radio operators looking to maximize their contact rates. As an experimental release, the software is subject to updates, ensuring continuous improvement and adaptation to user feedback.

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.

The KD6WD Moxon Antenna Project details the construction of 50-ohm two-element wire beam antennas, specifically Moxon rectangles, for the 10, 15, 17, and 20-meter bands. It utilizes AC6LA's software for critical measurement calculations (A-E) based on center frequency and wire size. Construction involves 16-gauge silver-coated copper wire, 16-foot telescoping fiberglass crappie fishing poles as spreaders in an "X" configuration, and various hub designs including aluminum tubing or PVC joints. A 1:1 current balun is used at the feedpoint, with wire nuts for connections, often achieving a 1:1 SWR across the design band. The project highlights practical applications, such as running a kilowatt into the antennas for greyline DX contacts, consistently yielding excellent signal reports. Comparisons to quad loops show 4 to 5 S-unit improvements in both receive and transmit. The Moxon design, according to L.B. Cebik's analysis, offers superior forward gain and front-to-back ratio among wire beams. The author notes a "DX-Vane" effect where a freely suspended Moxon automatically points to the strongest DX signal. Attempts at dual-band operation (17/20 meters) with a single feed were unsuccessful, reinforcing the Moxon's monoband nature, with EZNEC plots provided for a 17-meter Moxon at 30 feet.

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.

Indoor multiband dipole with EZNEC data files for simulation and analysis. Includes details on construction, tuning, SWR plots, and software usage. This page includes two different dipoles, a first version for 20-10 meters and an extended version covering 40-10 meters allowing a full coverage of most used ham radio HF Bands.

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.

Article by DK5WL describes a multi-band DX antenna for the 160m-40m amateur radio bands with low visibility but great performance for long distance communication.

This PDF File desscribes how to homemade a multi-band end-fed trapped wire antenna resonating on the low bands of 160 80 and 40 meters. Contains trap design instructions and some construction tips.

This Multiband Cubical Quad antenna a boomless Quad design with glass-fibre arms and a single coax wire connected to a remote antenna switch. This aerial work on 8 bands and has a 60-degree beam width. Despite achieving critical technical requirements, the antenna's three-dimensional structure presents obstacles, such as installation issues on fixed towers and risk of frost damage. The spider framework is built of stainless steel, with a compact 18-inch boom and strong angle iron arms. Tait use a variety of methods to fasten element wires and suggests placing them on the outside of the spreaders for improved insulation. The use of nylon twine or parachute cord between key attachment points allows for adjustable separation between pieces.

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.