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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.

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.

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.

Constructing a 2.4 GHz high-gain _cantenna_ for wireless networks is detailed, providing a practical approach to extending WiFi range. The author, WB8ERJ, shares insights into building these devices, noting their application in amateur radio for projects like Hinternet or HSMM (High-Speed Multimedia) networks. The article outlines the necessary components and steps, emphasizing the DIY aspect for hams interested in digital modes and local area networking. The resource explains how to determine the correct probe placement within the can, a critical dimension for optimal performance at 2.4 GHz. It references specific measurements, such as the 1.25-inch distance from the can's bottom, derived from calculations for the 2.4 GHz band. This precision ensures the antenna functions effectively for its intended purpose of signal amplification. Readers gain actionable knowledge for fabricating a functional antenna from common materials, suitable for experimentation or practical deployment in a ham shack or field environment. The focus remains on the hands-on construction and the measurable results of improved signal strength.

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.

This loop it is small and light enough to carry while operating, it disassembles into small but rugged pieces that fit easily in a backpack or gym bag, and it can be tuned from 14 MHz to 30 MHz. This tunable magnetic loop antenna is my contribution to the well established art of amateur loop making. Can be tuned from 14 MHz to 30 MHz.

This resource details the fundamental aspects of deploying longwire antennas, emphasizing ease of construction and installation for shortwave listening (SWL) and broadcast reception. It covers wire gauge selection, suggesting 14 to 24 AWG for general use, with heavier gauges (14-20 AWG) for permanent outdoor installations. Guidance is provided for various deployment scenarios, including indoor setups where the wire can be run around a room, temporary outdoor installations from balconies using light 18-24 AWG wire, and permanent outdoor configurations requiring higher placement and slack for tree movement. Feeding methods are discussed, recommending coaxial cable (50-75 ohms) to mitigate man-made interference, with instructions for connecting only the center conductor to the longwire. Safety precautions are highlighted, particularly avoiding contact with power lines and conductive materials, and managing static electricity buildup by unplugging the antenna after use and bleeding off charges before connection. The article also advises against using outdoor longwires during thunderstorms or snowstorms due to static and lightning risks. Optimal height considerations are presented, advocating for the highest safe placement, ideally a couple of feet above underlying structures, to maintain free air space. The text mentions a personal setup with one end at a roof peak (20 feet) and the other at a 17-foot mast, illustrating practical deployment without strict height requirements beyond safety and clearance.

Presents the official online presence for Yaesu, a prominent manufacturer of radio communication equipment. The site details their extensive product lines, encompassing amateur radio transceivers, antenna rotators, tuners, amplifiers, and various accessories like microphones, speakers, and power supplies. It functions as a central hub for product information, specifications, and support resources. The resource categorizes its offerings across several key areas, including **Digital Mobile Radio (DMR)** solutions, HF/VHF/UHF transceivers, and specialized receivers and scanners. Each product section typically includes model numbers, feature highlights, and often links to manuals or technical documentation, providing hams with essential data for equipment selection and operation. Beyond amateur radio, the site also covers Yaesu's contributions to aviation and marine radio sectors, illustrating the company's broader scope in wireless communication technology. It serves as a direct portal for accessing manufacturer-provided details, ensuring accuracy and currency for those researching Yaesu gear.

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**.

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 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.

4nec2 is a completely free Nec2, Nec4 and windows based tool for creating, viewing, optimizing and checking 2D and 3D style antenna geometry structures and generate, display and/or compare near/far-field radiation patterns for both the starting and experienced antenna modeler. Can be interfaced to HFwin32 propagation prediction software.

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.

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.

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.

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.

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.

Normal mode helix antennas offer a solution for HF mobile operators facing significant height restrictions, such as those parking in indoor garages with limited overhead clearance. This design, adapted from concepts typically applied to VHF/UHF rubber duck antennas, allows for extremely shortened HF radiators that remain effective for county hunting and general mobile operation. The resource details the construction of a 20-meter helix antenna, approximately 10 inches long, wound with #14 AWG THHN wire on a 1 1/2-inch CPVC form, mounted on a standard 3/8 x 24 antenna stud. Mark Herson, _N2MH_, shares his experience developing these antennas, including initial research from the _RSGB VHF UHF Manual_ and practical winding experiments to establish the relationship between turns and resonant frequency. He provides coil data for various frequencies, emphasizing that these measurements were taken with an _MFJ-259a_ antenna analyzer and are dependent on the vehicle's grounding system. Despite their shortened nature, N2MH confirms the antennas' operational effectiveness, citing contacts with KL1V in Alaska on 20 meters and E-skip contacts on 10 meters. The design prioritizes continuous deployment without removal, making it suitable for operators who frequently navigate height-restricted environments.

Alinco's factory in Toyama, Japan, holds ISO9002/140001 certification, underscoring its commitment to quality manufacturing processes for amateur radio equipment. The company produces a diverse range of products, including HF transceivers, mobile VHF/UHF radios, handhelds, and scanners, serving both new and experienced operators within the ham radio community. Their product line extends beyond transceivers to encompass essential accessories such as antenna tuners and power supplies, which are crucial for complete station setups. These offerings support various operating environments, from portable field operations to fixed home stations, ensuring versatility for radio amateurs. Alinco, Inc. Electronics Division is headquartered at Yodoyabashi Dai-Bldg 13F, 4-4-9 Koraibashi, Chuo-ku, Osaka 541-0043 Japan, maintaining a global presence in the amateur radio market.

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

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

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.

Delta Loop Antenna for 15m band. This antenna is made for operating from outdoors, mainly from mobile shack. Drive to a parking you like, then build it up. Just half an hour later, you can enjoy slightly better gain than normal dipole.

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

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

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

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

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

Examines the practical considerations and technical challenges of deploying mobile antennas for 10-meter operation, particularly for operators on the move. It addresses the inherently _lossy_ nature of shortened, loaded vertical antennas typically used in mobile configurations, encouraging hams to view these limitations as engineering challenges. The resource provides actionable advice on safeguarding vehicle electronics, selecting appropriate cabling like _RG-213_, and properly grounding antenna mounts to the vehicle chassis. Specific mounting strategies are detailed, including roof, trunk lip, and side-mounting for trucks and vans, along with their respective advantages and drawbacks. It emphasizes the importance of a robust ground plane and suggests methods for improving grounding beyond simple set screws. The article also touches on antenna choices, mentioning "bugcatchers" and "Hamstick types" as viable options for 10 meters. Furthermore, the guide transitions to stationary mobile operation, where antenna options expand significantly. It outlines how to deploy portable dipoles or 2-element beams from a parked vehicle, offering practical tips for assembly, storage, and mast guying using simple materials like a concrete block. It notes that a 5/8 wavelength height, approximately **20 feet** on 10 meters, often yields good short-skip and DX performance, even with a take-off angle above **20 degrees**.

A 10-meter J-Pole antenna, detailed in QST February 1950, offers a straightforward solution for hams operating with restricted space. This design, originally presented by W1BLR, is a **half-wave radiator** fed by a quarter-wave matching stub, providing a low-angle radiation pattern beneficial for DX. The article describes building the antenna from readily available materials like copper pipe, emphasizing its simplicity and effectiveness for **single-band operation**. The J-Pole's inherent design provides a good impedance match to 50-ohm coaxial cable without the need for an external tuner, a significant advantage for portable or minimalist stations. Its nondirectional pattern ensures coverage in all directions, making it a versatile choice for general operating on the 28 MHz band. The construction plans are clear, allowing even those with basic workshop skills to assemble a functional antenna.

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

Over 40 years of experience inform the reviews and commentary presented on Dave's Radio Receiver Page, covering a wide array of radio receivers and transceivers. The resource details specific models such as the **ICOM IC-R8600** SDR Communications Receiver, which is lauded as Icom's best wide-band receiver, even surpassing the IC-R9500 in performance. Other notable reviews include the ICOM IC-7300 HF Transceiver, highlighting its direct sampling SDR technology and spectrum scope capabilities, alongside numerous models from Japan Radio Co. (JRC), Kenwood, Yaesu, and various portable shortwave receivers. The content provides practical insights into the performance and characteristics of each radio, often drawing comparisons between models. For instance, the early issues with the AOR AR7030 receiver's Bourns mechanical encoders are thoroughly documented, including AOR's eventual switch to higher-quality Alps encoders. The page also features reviews of antennas like the MFJ-1026 Noise Canceling Signal Enhancer and various power supplies, offering a holistic view of radio monitoring setups. The author's "2 ear / 2 eye method" emphasizes real-world listening experiences over laboratory measurements, providing a unique perspective on equipment utility.

The Petlowany Three-Band Burner is a simple, low-cost, trapless short vertical antenna which amazingly works on three HF bands (20, 15 and 10 meters). This web page contains pictures, performance data, and enough construction details so you can homebrew your own.

How to make a wifi cantenna using a mini ravioli can

Freeware antenna software that lets you see what the polar diagram of your rotatable beam actually looks like where it is operating. With PolarPlot you can measure the polar diagram of the antenna and check for abnormalities - compare plots taken before and after changes to the design or location - check the -3dB beamwidth - look at the front to back ratio - see the size and position of the sidelobes.

The **NW3Z** optimized wideband antenna designs, originally presented at Dayton 2001, detail Yagi configurations for the 20-meter, 15-meter, and 10-meter amateur radio bands. This resource provides access to the design files, likely containing critical parameters such as element spacing, element lengths, and boom dimensions, which are essential for replicating these directional antennas. The designs focus on achieving wide bandwidth, a desirable characteristic for contesters and DXers operating across a significant portion of each band. The content specifically references "nw3z-Antenna-DesignsDownload," indicating that the core information is available as a downloadable file, presumably in a format suitable for antenna modeling software or direct construction. Such files typically include **NEC models** or similar data, allowing for performance analysis and optimization before physical construction. The emphasis on "optimized wideband" suggests design considerations for SWR bandwidth and gain characteristics over a broader frequency range than typical narrow-band Yagis. The resource serves as a direct source for specific, proven antenna designs from a known amateur radio antenna designer, offering practical data for hams interested in building high-performance Yagi arrays for HF.

The resource details the construction and performance of a dual-band 40/30 meter _Moxon_ antenna, evolving from an initial single-band 30-meter design that failed in a storm. It specifies materials such as four 10-meter fishing rods, galvanized iron TV antenna support pipes, 1mm diameter PVC-covered copper wire, and a piece of 75-ohm TV satellite cable for feedline. The document outlines the iterative design process, including initial resonance measurements of 9.9 MHz for 30 meters and subsequent recalculations to shift the center frequency by 300 kHz using _Moxon software_. Initial testing on a roof yielded SWR readings of 1.4:1 at 7.200 MHz and 1.5:1 at 10.280 MHz. After installation atop a 30-meter tower, the final SWR measurements were 1.1 at 7.130 MHz and 1.4 at 10.230 MHz, with a notable 30 dB front-to-back ratio on 40 meters. The 30-meter performance, while good, showed a front-to-back ratio of approximately 15 dB, suggesting a slightly high resonance. The antenna's placement on a 700-meter hill, with a significant ground drop in certain directions, is noted as a potential factor in its excellent DX performance, enabling daily contacts with the USA West Coast on 30 and 40 meters with 100 watts.

F6EZX presents a detailed account of constructing a compact, multi-band _Levy antenna_ for portable holiday operations, specifically addressing issues with local QRM from a previous _Deltaloop_ setup. The article outlines the design criteria, including multi-band operation on 40m, 30m, 17m, 15m, 12m, and 10m, a symmetrical configuration to reduce interference, and a low take-off angle for DX. Construction involves 2x 10.3m radiating elements and a 15.3m open-wire feeder (ladder line) with 7cm spacing, made from 1.5mm2 copper wire and foam pipe insulation spacers. Theoretical calculations, referencing F9HJ's "_Les antennes Levy_" book, guide the determination of element lengths and feeder impedance characteristics, aiming for a good match across bands with a commercial antenna tuner. Initial field tests with the _VCI Vectronics VC300DLP_ tuner showed a 1:1 SWR from 80m to 10m, with some difficulty on 17m. The antenna, mounted as a 45-degree slopper with the high point at 12m, successfully facilitated DX contacts to South America, particularly Chile and Argentina, suggesting a lower take-off angle compared to the previous Deltaloop which favored Brazil. The Levy antenna significantly reduced TVI/RFI, attributed to its improved symmetry and greater distance from the QRA. While signal reports on 15m and 20m were 1-2 S-points lower than the Deltaloop, its performance on 40m and 30m was comparable, fulfilling the design goals for a portable, low-cost, multi-band solution.

The W3DZZ trap dipole is a versatile and economical antenna option for amateur radio operators looking to work multiple bands without the need for extensive equipment. This antenna design utilizes traps to allow operation on various HF bands, making it suitable for both casual operators and serious DXers. Its construction is straightforward, making it accessible for beginners while still providing excellent performance for seasoned hams. Constructed with readily available materials, the W3DZZ trap dipole can be built to fit specific band requirements, allowing operators to optimize their setup for the frequencies they intend to use. The design is particularly favored for its ability to maintain a low profile while delivering effective radiation patterns. Whether you're contesting or chasing DX, this antenna can enhance your station's capabilities without breaking the bank.

Constructing a **2-meter** J-pole antenna from readily available copper plumbing components offers a robust and cost-effective solution for VHF operation. This design, dubbed the "Plumber's Delight," functions essentially as a half-wave dipole fed by 50-ohm coax via a **gamma match**. It incorporates a quarter-wave copper tubing support, which, when affixed to a metal mast or tower, enhances forward power in the direction of the radiating elements. The original configuration utilized a small ceramic trimmer capacitor for the gamma match, suitable for up to 10 watts. A subsequent modification replaced this with a 50 pF variable capacitor housed in a plastic enclosure, accommodating higher RF power and improving weather resistance. The antenna elements are secured using a copper "T" fitting, and an SO-239 connector mounts directly to this fitting. Performance includes gain away from the support mast, and tuning is straightforward by adjusting the gamma match capacitor for a 1:1 SWR. The total cost for materials, excluding the capacitor and coax, can be under $10.

QTH.COM offers a comprehensive platform for amateur radio enthusiasts to buy, sell, and trade equipment. This online service is designed to facilitate transactions between hams, allowing users to list their gear for free. Whether you're looking for HF or VHF equipment, antennas, or even vintage radios, QTH.COM serves as a hub for all your ham radio needs. The site is user-friendly and accessible, making it easy for both seasoned operators and newcomers to navigate the listings. In addition to individual sellers, QTH.COM also attracts dealers and manufacturers looking to reach a wider audience. With a diverse range of categories, including military radios and radio tubes, users can find unique items that may not be available elsewhere. The platform's commitment to providing a free service ensures that all hams can participate in the marketplace without financial barriers. Join the community at QTH.COM and discover the best deals in the ham radio world.

W5ALT Indoor Vertical Antenna is a base loaded vertical antenna that can be tuned on almost all HF bands by adjusting a big coil. Operating a ham radio station from an apartment in Maracaibo, Venezuela, the author demonstrates effective communication with over 100 countries using a custom-built indoor vertical antenna. Addressing common misconceptions, the design uses a balanced approach with radials and a base-loaded vertical element made from affordable materials. The antenna fits discreetly indoors, covers 6 to 40 meter bands, and achieves acceptable SWR with an MFJ tuner. Despite limited space and typical apartment challenges, the setup enables reliable DX contacts, confirmed by numerous QSL cards, proving indoor antennas can perform well in constrained environments.

Examines the operational principles of loading inductors within **mobile HF antennas**, clarifying their role in canceling capacitive reactance rather than physically replacing missing antenna length. It meticulously details how current distribution is influenced by stray capacitance and termination impedance, rather than the physical length of wire within the coil itself. The resource provides a deep dive into the behavior of inductors, emphasizing that a loading coil functions identically to any other inductor in an electronic circuit, with its characteristics determined by its design and surrounding impedances. This article specifically addresses common misconceptions, such as the idea that loading coil current is reduced by standing waves or that coils introduce a significant electrical-degree phase delay related to conductor length. It explains that magnetic flux coupling within the coil causes charges to move at light speed, resulting in minimal time delay across the inductor, especially in well-designed, compact units. The author, W8JI, presents both theoretical explanations and empirical measurements to support these points, including data from various antenna configurations. Furthermore, the content clarifies the distinction between voltage-current phase shift within an inductor and actual current time delay through it, using **SPICE models** and real-world observations. It highlights that large current taper in a loading coil often indicates poor antenna or tank circuit layout, rather than an inherent property of the inductor itself. The discussion also touches on the impact of stray capacitance on inductor Q and bandwidth, offering insights into optimal form factors for different applications.

Also known as W0MHS Loop Skywire or Full Wave Loop Antenna, here you can find N1SU interesting observations on this antennas.

A 3.42-meter (11-foot 2-inch) extended-length mobile antenna project is presented, detailing its evolution from an initial 1.65-meter design. W5JGV shares his journey in optimizing mobile HF performance, noting that increasing the top whip length significantly improved radiation efficiency by reducing coil losses and allowing for larger wire gauges. The article includes a comparative table illustrating substantial gain increases, with the 3.42-meter version showing up to 40.6% efficiency on 21.2 MHz compared to a half-wave dipole. Construction details are thoroughly documented, from the use of hard-wall copper pipe for mast sections to the fabrication of custom loading coils. The author explains the necessity of an insulating brace for self-supporting coils and details a unique rotational alignment mechanism for off-center mounted coils to prevent snagging on overhead obstructions. He also describes a "Z" winding technique for 75-meter and 160-meter coils, which minimizes copper losses and manages dielectric losses. The resource provides specific loading coil data, including wire gauge, number of turns, coil length, and inductance values for bands from 18 MHz down to 2 MHz. It emphasizes that these coils may require fine-tuning based on individual vehicle and whip configurations, suggesting an antenna tuner for optimal mobile station operation across multiple HF bands.

End-Fed Half-Wave Antennas (EFHWAs) are analyzed for their utility in portable QRP operations, emphasizing their simplicity, efficiency, and predictable radiation patterns compared to other portable antenna types. The discussion contrasts EFHWAs with vertical antennas, random length wires, and center-fed dipoles, highlighting the common pitfalls of each, such as ground system dependency for verticals and feedline issues for dipoles. The article details the electrical half-wavelength calculation using the formula L (Ft) = 468/F(MHz) and explains how EFHWAs can be resonant on harmonic frequencies, enabling multiband operation. Various deployment configurations are presented, including the inverted L, inverted Vee, sloping wire, and vertical setups, each with specific advantages for radiation angle and polarization. For instance, a vertical EFHWA offers a low angle of radiation suitable for DX contacts without requiring an extensive ground system. The resource also addresses the counterpoise requirements, suggesting a quarter-wavelength wire or connection to a metallic structure for decoupling. A schematic diagram for a simple parallel-tuned circuit tuner, based on the _Rainbow Bridge/Tuner_ design, is provided, detailing component values for 30 and 40 meters, including a 6 microhenry toroidal inductor and a 20-100 picofarad mica compression capacitor. The tuner's adjustment process for SWR matching is also outlined.

Presents the design and construction of an automatically tuned 7-30 MHz mobile HF vertical antenna, originally published in _QEX / Communication Quarterly_ in 2003. The resource details a base-loaded vertical antenna system that mounts on a vehicle's roof, incorporating a variable inductor as its loading coil. A three-legged chariot, driven by a modified model airplane servo, travels inside the coil to adjust inductance. The control unit, featuring a _Basic Stamp microcontroller_ and SWR sensor, emulates a Kenwood AT-50 tuner for seamless integration with a _Kenwood TS-50_ transceiver, allowing automatic tuning across all ham bands from 40 to 10 meters. The project emphasizes practical application, providing a solution to the narrow-banded nature of mobile HF antennas and the inconvenience of manual band changes. It achieves a maximum SWR of 1.3:1 across its operating range. The mechanical design is thoroughly documented with detailed drawings, including a full-resolution GIF and AutoCAD R14 DWG files, illustrating components like the stainless steel whip, PVC coil tube, and the servo-driven chariot mechanism. Construction requires a lathe, but the author notes it can be accomplished with a hobby lathe, making it accessible to those with moderate mechanical skills.