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Demonstrating the construction of a short dipole antenna tailored for the 60 meter band, this resource provides detailed instructions for radio enthusiasts with limited space. The design incorporates inductive loading using two inductors (L1/L2) made from PVC tubes, allowing for effective operation on 5 MHz. The antenna consists of 12 meters of wire, divided into four sections, with specific dimensions and materials outlined for optimal performance. Results from users indicate that this antenna can significantly enhance DXing capabilities on the 60 meter band. Feedback from operators suggests that while the design is effective, adjustments may be necessary based on individual setups, such as coil diameter and wire gauge. Many users report successful construction and operation, with some experimenting with variations to improve resonance. The practical application of this antenna design has led to successful contacts and improved signal quality, making it a popular choice among 60 meter band operators.

This article describes the details of the design, which can be easily scaled for just about any HF band. The antenna described in this article is for the 20 meters band.

Getting the most out of LowFER transmitting antennas, designing an efficient antenna for the 1750-meter band by K0LR

The **Solarcon A99** vertical antenna, a half-wave over a quarter-wave variable mutual inductance design, primarily serves the 11-meter CB band but also finds use on 10 and 12 meters for amateur radio operators. Its simple construction, consisting of three fiberglass sections and a 16 AWG radiating element, makes it an accessible option for new operators or those seeking an easy-to-install base station antenna without complex mounting requirements. Despite claims of 9.9 dBi gain being widely considered exaggerated, and a manufacturer rating of 2000 watts power handling often viewed with skepticism (with 300 watts suggested as a practical limit), the A99 maintains popularity due to its low cost and ease of deployment. It typically tunes to a 1.2-1.3 SWR out of the box, requiring minimal adjustment via its two tuning rings. Its high angle of radiation allows for effective local communication even when mounted at low heights, such as 8-10 feet off the ground. However, the A99 is known for significant RF bleed-over issues, particularly when operated with higher power or mounted close to residential electronics. While its internal design is often described as cheap, the antenna exhibits remarkable durability, frequently lasting a decade or more in various weather conditions. Its affordability and straightforward setup continue to make it a go-to choice for many radio enthusiasts.

This is a presentation used at OVARC on the LindenBlad antenna construction. The presentation cover several topics about this antenna, from the basic antenna design, to the guide on how to contruct a custom lindenblad antenna for the 2 meters band and and 70 centimenters band.

There are a large number of antenna designs for HF. One choice out of many is the fan dipole. The ability to transmit of multiple bands without needing a tuner (and even more with a tuner) is a very desirable factor in choosing a versitle antenna for HF.

US amateur radio antenna manufacturer, design and build monoband, dual band and multiband Yagi Antennas for HF bands as well as receive antenna systems

The Icom AH-4 autotuner operates efficiently across multiple HF bands, providing seamless automatic tuning for antennas from 3.5 MHz to 54 MHz. Its robust design allows for outdoor installation, making it suitable for field operations and fixed stations. The unit interfaces with Icom transceivers via a control cable, enabling automatic band switching and tuning. The AH-4 is capable of handling up to 120 watts of RF power, ensuring compatibility with most amateur radio setups. Its weather-resistant casing and compact form factor make it a versatile choice for operators requiring reliable performance in diverse environments. Field tests demonstrate the AH-4's ability to maintain low SWR across its operational range, enhancing signal quality and transmission efficiency. Compared to manual tuners, the AH-4 offers significant time savings and ease of use, particularly in rapidly changing band conditions. Its integration with Icom radios simplifies operation, eliminating the need for manual adjustments. The autotuner's performance is consistent with other high-end models, providing a cost-effective solution for amateur operators seeking dependable tuning capabilities without sacrificing performance.

A DIY Automatic Band Decoder (ABD) project, designed for dual-radio operation, addresses the common challenge of integrating band data with older transceivers lacking dedicated outputs. This particular build utilizes an AVR AT90S8515 microcontroller and a 16x2 Liquid Crystal Display (LCD) to provide band information, specifically targeting Kenwood rigs via a computer's LPT port. The design aims for cost-effectiveness while maintaining functionality, offering a solution for hams seeking to add automatic band switching capabilities to their station without significant expense. The project outlines the core components required, including the microcontroller, LCD, and an enclosure, noting that the Printed Circuit Board (PCB) fabrication and AVR programming might present challenges for some builders. It details the input requirements, such as a four-pin input and PTT for each radio, along with a 13.8V DC power supply. The decoder provides 2x6 outputs capable of sinking 500mA, suitable for controlling external devices like antenna switches or filters. Despite the original unit being damaged by a lightning strike in 2004, the author confirms its successful operation prior to the incident and mentions plans for a revised version. The resource includes a schematic in PDF format and images of the finished PCB and assembled unit, demonstrating the practical implementation of the design.

Design and build a 6 meter 2-element Moxon antenna mostly from available aluminum tubing and angle stock.

Optimizing weak signal reception on the HF bands, particularly in the presence of strong local QRM, often necessitates specialized receiving antenna systems. This resource details the _HI-Z Antennas_ product line, focusing on phased vertical arrays designed for superior noise rejection and directivity. It covers components such as the 4-Square and 8-Element array controllers, which allow for rapid switching of receive patterns, and dedicated low-noise preamplifiers to improve system sensitivity. The site also presents various bandpass filters, crucial for mitigating out-of-band interference and enhancing the dynamic range of the receiver. The HI-Z systems are engineered to provide significant front-to-back and side rejection, often yielding **20-30 dB** of attenuation to unwanted signals, which is critical for DXing and contesting. Users can achieve a notable reduction in local noise, allowing for the discernment of signals that would otherwise be buried. The array controllers facilitate quick pattern changes, enabling operators to null out interference or peak weak signals from distant stations, effectively extending the reach of their receive capabilities by improving the signal-to-noise ratio.

This kind of antenna has grown in popularity over the last years because it gives you a decent performance and triband capabilities. But its 50 MHz design is far from optimal. Here you can learn how to improve its 50 MHz performance in a very easy way.

The Buddipole Deluxe, a portable HF/VHF antenna system, receives a practical assessment from IW5EDI after a month of field use. The author, constrained by antenna restrictions, highlights the system's crucial role in enabling portable operations, even managing sporadic digital activity from a balcony. Direct comparisons to a fixed 3-band dipole reveal surprisingly comparable signal reports on 15, 17, and 20 meters, underscoring the Buddipole's effectiveness in real-world scenarios. Tuning the Buddipole proves straightforward on bands down to 20 meters, though the review notes significant challenges with SWR on lower bands like 40 meters, where achieving better than 3:1 SWR was problematic. Observations also include SWR variations with dipole rotation and mast height, suggesting environmental factors play a role. The overall manufacturing quality of the antenna and its accessories, including the tripod and carry bag, is deemed good, despite a minor issue with a pole connector. Looking ahead, the author plans to construct a homemade Buddipole version, possibly optimized for the 30-meter band, specifically for PSK31 operations from an apartment. This personal project reflects a common amateur radio practice of adapting commercial designs for specific needs, further extending the utility of portable antenna concepts.

A bazooka coax antenna for 40 meters band design by CA6TYS

A 70 cm yagi designed for EME + SSB narrow bandwidth version, strictly G/T breeding. This little Yagi has a high F/B, which makes it quite useful as a contest stack

Demonstrates the swift setup process for a **Trans World Antenna**, showcasing its utility for portable amateur radio operations. The video highlights the antenna's design for quick deployment, a critical factor for activations like Summits On The Air (SOTA) or Parks On The Air (POTA), where efficiency in establishing a station is paramount. It illustrates the physical components and the sequence of assembly, emphasizing ease of use in varied field environments. The antenna system is presented as a multi-band solution, capable of operating across various HF frequencies. This adaptability makes it a versatile choice for hams engaging in outdoor activities or emergency communications. The visual demonstration provides practical insights into managing the antenna elements and feedline for optimal performance during temporary deployments. The focus remains on the practical aspects of field setup, rather than detailed technical specifications or performance metrics.

The _Sci.Electronics FAQ: Repair: RFI/EMI Info_ document, authored by Daniel 9V1ZV, provides a detailed analysis of computer-generated RFI/EMI, focusing on its impact on radio reception. It identifies common RFI sources such as CPU clock rates (e.g., 4.77 MHz to 80 MHz), video card oscillators (e.g., 14.316 MHz), and even keyboard microprocessors, all of which generate square-wave harmonics across HF and L-VHF regions. The resource outlines a systematic procedure for pinpointing RFI origins, including disconnecting peripherals and using a portable AM/SW receiver with a ferrite rod antenna to localize strong interference sources. The document categorizes RFI mitigation into shielding, filtering, and design problems, offering practical solutions for each. It recommends applying conductive sprays like _EMI-LAC_ or _EMV-LACK_ to plastic casings of radios, monitors, and CPUs to create effective Faraday cages, emphasizing proper grounding and avoiding short circuits. For filtering, the guide suggests using line filters, ferrite beads, and toroids on power and data lines, and small value capacitors (e.g., 0.01 uF for serial/parallel, 100 pF for video) to shunt RFI to ground. It also discusses the use of bandpass, high-pass, low-pass, and notch filters on the receiver front-end or antenna feed to combat specific in-band noise.

The TransWorld Antennas TW4040 The Adventurer Monobander™ is a portable HF antenna designed for rapid deployment in field operations, including **SOTA** and **POTA** activations. This manual details the antenna's assembly, tuning procedures, and operational guidelines for optimal performance on the 40-meter band. It outlines the specific components, such as the telescoping whip and base unit, required for proper setup. Instructions cover mast erection, radial wire deployment, and impedance matching to achieve a low **VSWR** across the designated frequency segment. The document also provides guidance on antenna orientation and environmental considerations for portable use. It specifies the antenna's power handling capabilities and physical dimensions when fully deployed and collapsed for transport.

Operating a ham station often involves encountering radio frequency interference (RFI), RF feedback, or RF burns, which are frequently misattributed to poor equipment grounding. This resource meticulously dissects these assumptions, asserting that RF grounds on the operating desk often merely mask more significant system flaws. It identifies five primary causes for RF problems, including antenna system design flaws, proximity of the antenna to the operating position, DC power supply ground loops, equipment design defects, and poorly installed connectors or defective cables. The content emphasizes that issues like "hot cabinets" or changes in SWR when connecting a ground indicate substantial RF flowing over wiring or cabinets, a phenomenon known as common-mode current. The article provides detailed explanations of common-mode current generation, particularly from single-wire fed antennas like longwires, random wires, and OCF dipoles, which inherently present high levels of RF in the shack. It also illustrates how vertical antennas, lacking a perfect ground system, can excite feed lines with significant common-mode current. Through simulations, the author demonstrates how a dipole without a proper _balun_ can cause RF problems at the operating desk, showing current patterns and voltage distributions on feed line shields. The discussion extends to the proper application of _RF isolators_ and _ferrite beads_, clarifying their role in modifying common-mode impedance on cable shields and cautioning against their use as a band-aid for fundamental system defects. The resource advocates for correcting the actual source of RF problems, such as antenna system issues or poor connector mounting, rather than relying on internal shack grounding or isolators. It highlights that properly functioning two-conductor feed lines, like coaxial or open-wire lines, should result in minimal RF levels at the operating position, even without a desk RF ground. The author shares personal experience, noting that his stations since the late 1970s have operated without RF grounds at the desks, relying instead on proper antenna system design and feed line integrity.

The collinear antenna, or Marconi-Franklin antenna, is an omnidirectional, high-gain antenna composed of in-phase half-wave dipoles aligned vertically. By using quarter-wave transmission line segments, it maximizes gain at a low horizon angle, outperforming a half-wave dipole. Adding segments increases gain but narrows bandwidth. A popular DIY version, the CoCo antenna, uses half-wave coaxial cable segments connected by non-radiating transmission lines. Built with stable velocity factor cables, a matching quarter-wave sleeve balun, and ferrite rings for attenuation, the antenna achieves performance comparable to commercial models.

Such kind of omnidirectional antenna gives the possibility to be QRV with horizontal polarisation, as commonly used for the CW and SSB section of the 2m band. This actual design shows a 1.3:1 bandwidth of about 150kHz, centered to 144.200MHz.

Constructing a compact directional antenna for the 17-meter band, this resource details the build process for a Moxon rectangle, a two-element Yagi variant with folded-back elements. It covers the antenna's evolution from the _VK2ABQ beam_ and provides specific dimensions for a version built using fishing pole whips. The content includes a discussion of the antenna's radiation pattern, feedpoint impedance, and its inherent front-to-back ratio, which is often superior to a standard two-element Yagi. Practical considerations for element spacing and material choices are also addressed, alongside a visual representation of the antenna's physical layout. Performance data presented includes a comparison showing the Moxon rectangle's **2.5 dB gain** over a half-wave dipole and a front-to-back ratio of **20 dB**. The resource also touches upon the antenna's relatively wide bandwidth for a two-element beam and its suitability for portable operations due to its compact footprint. It offers insights into optimizing the design for specific operating conditions and discusses the advantages of its lower take-off angle compared to omnidirectional wire antennas, making it effective for DX contacts on the 17-meter band.

The 160-meter amateur radio band, spanning 1.8 to 2 MHz, was historically the lowest frequency amateur allocation until the introduction of the 630-meter and 2200-meter bands. ITU Region 1 allocates 1.81–2 MHz, while other regions use 1.8–2 MHz. This band, often called "Top Band" or "Gentleman's Band," was established by the International Radiotelegraph Conference in Washington, D.C., on October 4, 1927, with an initial allocation of 1.715–2 MHz. Effective operation on 160 meters presents significant challenges due to the large antenna sizes required; a quarter-wavelength monopole is over 130 feet, and horizontal dipoles need similar heights. Propagation is typically local during the day, but long-distance contacts are common at night, especially around sunrise and sunset, and during solar minimums. The band experienced a resurgence after the LORAN-A system was phased out in North America in December 1980, leading to the removal of power restrictions.

The Superantennas MP-1 portable HF antenna is analyzed for its design and field performance, particularly its high-Q loading coil and 3/8-inch mounting. The review details the antenna's construction, including an 8-inch vertical section, a large-diameter loading coil tuned by a sleeve, and a 4-foot whip that disassembles into six rods for transport. Initial testing with the supplied 10-foot ribbon cable "ground plane" yielded poor SWR and RF hot conditions, indicating an inadequate ground system. Further experimentation with longer radials and resonant counterpoises for each band improved matching and eliminated RF hot issues, but introduced significant operational complexity. The author notes the difficulty in optimizing both counterpoise length and coil setting without an antenna analyzer, and the sensitivity of the MP-1 to counterpoise deployment. The review also discusses the recommendation to tune for maximum received signals rather than minimum SWR, often necessitating an external ATU due to the antenna's typical low impedance. The **MP-1**'s critical dependence on resonant counterpoises for effective operation, especially when elevated, is highlighted as a major drawback for portable use. The author ultimately sold the antenna, concluding that despite its sound technical design, its fussy nature and the need for extensive counterpoise management or an ATU detract from its portability and convenience compared to simpler, less expensive dipole solutions. The **Superantennas MP-1** is deemed a flawed portable antenna, requiring considerable effort to achieve its claimed performance.

T2FD is a 600-900 ohms folded dipole, terminated with resistor. Feed impedance is coupled with 50/600 ohms voltage balun. It is a wide band antenna with rather low SWR over the full designed frequency range: antenna tuner is seldom needed.

A simple, cheap and easy to build 26 feet long vertical antenna that works DX on 20 - 10 meters including WARC Bands, it is designed for portability for field days, camping, or permanent installation, cost, and to achieve at least 1/2 wavelength on the WARC bands.

Three Yagi antennas for the six meters band by 9A7PJT. Include a 4 element yagi, a custom design 4 element, and a 5 element yagi with antennas pictures and design.

Moxon is a rectangle shaped directional antenna, originally designed by Les Moxon G6XN. There are couple of advantages of using this antenna. It is small in size, Easy to mast, Balanced to 50 Ohms, Near 1:1 SWR, Excellent Front to Back (F/B) ratio, Large bandwidth

Designer and manufacture of Airborne Antenna & Radomes covering a range of applications. Products include vhf antenna ,uhf antenna,navigation antenna,comm antenna,blade antenna,vor/ils antenna ,L band antenna, direction finding antenna,DF antenna,vor,ils, IFF antenna on aircraft,aircraft antenna for airborne application.

The article, "Using 75 Ohm CATV Coaxial Cable," details methods for employing readily available 75-ohm CATV hardline in standard 50-ohm amateur radio setups. It addresses the inherent impedance mismatch and practical considerations, such as connector compatibility, for hams seeking cost-effective, low-loss feedline solutions. The resource specifically contrasts common 50-ohm cables like RG-8, RG213, and _LMR-400_ with 75-ohm hardline, highlighting the latter's lower loss characteristics, particularly at VHF and UHF frequencies. It explores two primary approaches to manage the impedance difference: direct connection with an acceptable SWR compromise and precise impedance transformation. The direct connection method acknowledges that a perfect 1:1 SWR is not always critical, especially when using low-loss coax. For impedance transformation, the article explains the use of half-wavelength sections of coax to reflect the antenna's 50-ohm impedance back to the transmitter, noting its single-frequency effectiveness. It also briefly mentions transformer designs using toroid cores and a technique involving two 1/12 wavelength sections of feedline for broader bandwidth. The content further clarifies the concept of _velocity factor_ for calculating electrical versus physical cable lengths, providing a generic formula for precise length determination. It notes that while half-wave matching is practical for 10 meters and above, it can result in excessively long runs for lower bands like 160 meters, potentially adding **250 feet** of cable. The article also mentions achieving a usable bandwidth of 28.000 MHz up to at least **28.8 MHz** on 10 meters with specific transformation techniques.

Design for a quarter wave vertical antenna, for the top band in use at V31YN

A 7 dB directional gain is reported for this portable VHF Yagi antenna design, which utilizes cut metal tape measure sections for its elements. The resource details the construction process for a 2-meter band antenna, emphasizing its ease of build and portability. It specifically mentions the design's suitability for radio direction finding (RDF), fox hunting, and communication with satellites and the International Space Station (ISS), highlighting its practical applications for amateur radio operators. The construction cost is estimated at under $20, with potential for even lower expense if salvaged materials like old tape measures and PVC pipes are used. The article references _Joe Leggio's_ (WB2HOL) original design, noting specific alterations made by the author. It also compares this design to other DIY Yagi antennas, including _FN64's_ 2-meter band and _manuka's_ 70-cm band tape measure Yagis, underscoring its unique combination of simplicity, portability, and effective performance with a 1:1 SWR achievable on the 2-meter band.

A 102-inch vertical whip, commonly a CB antenna, forms the core of this low-profile 10-meter antenna design, optimized for the 28 MHz band. The construction details specify three 8-foot radials made from scrap wire, connected to a common point. This simple yet effective setup is designed for ease of construction and deployment, making it accessible for operators with limited space or materials. The design emphasizes using readily available components, including PVC pipe for the mast and a SO-239 connector for the feedline, ensuring a straightforward build process for a resonant quarter-wave vertical. Field results indicate that this antenna provides good performance for local and DX contacts on 10 meters, despite its compact footprint. The author, N8WRL, shares practical insights into its construction and tuning, highlighting its suitability for temporary or permanent installations where a full-sized antenna might be impractical. Comparisons to more complex designs suggest that this low-profile vertical offers a respectable signal-to-noise ratio and effective radiated power for its size, proving that simple designs can yield satisfying on-air results.

This web article details the construction of a 4-meter band coaxial dipole antenna, designed for operation between **70.000 MHz and 70.500 MHz**. The resource provides a bill of materials and step-by-step assembly instructions for a half-wave dipole constructed from _RG-58_ coaxial cable. The design specifies a direct 50 ohm feedpoint impedance, eliminating the need for an external matching network. Construction photographs illustrate the stripping and soldering processes for the coaxial cable elements, ensuring proper electrical connection and physical integrity. The article includes specific dimensions for the radiating elements, derived from calculations for the 70 MHz band. The project outlines the physical dimensions required for resonance at 70 MHz, with the outer braid forming one half and the inner conductor forming the other. The feedline connection is directly to the coaxial dipole's center, maintaining a 50 ohm characteristic impedance. While the article does not present SWR plots or VNA sweeps, it focuses on the mechanical construction and dimensional accuracy for achieving a functional 4-meter dipole. The design is intended for fixed station use, with no specific mention of polarization or height above ground, but implies a standard horizontal orientation for dipole operation. DXZone Focus: Web Article | 4m Coaxial Dipole | Construction Guide | 50 ohm Feed

A delta loop antenna for 20 meters band designed with MMana with a tuning system made in a classic stub configuration

The Hexbeam is a great little antenna! It should be high on your list of options if you want a design that can be multi-banded, exhibits useful gain and directivity, is very lightweight, has a small turning radius, and which lends itself readily to Do It Yourself construction.

SPX Communication Technologies, operating under the TCI International brand, presents a range of radio frequency (RF) solutions primarily for government, defense, and commercial sectors. The offerings include advanced systems for spectrum monitoring, communications intelligence (COMINT), and high-frequency (HF) and medium-frequency (MF) broadcasting and communication antenna systems. Specific product lines encompass _Blackbird_ COMINT systems, _Scout_ spectrum monitoring receivers, and various antenna arrays designed for robust performance in challenging RF environments. The resource details the capabilities of these systems, such as wideband signal detection, direction finding (DF), and signal analysis, crucial for intelligence gathering and regulatory compliance. It also highlights the engineering behind their antenna designs, which are optimized for specific frequency ranges and operational requirements, including high-power broadcast applications and secure military communications. The information presented emphasizes the integration of hardware and software for comprehensive RF situational awareness. The company's focus on empowering partners to "Command the Spectrum" underscores its commitment to delivering critical tools for signal interception, analysis, and management across diverse operational landscapes.

Documents the construction of a **VHF/UHF** antenna addition for the Buddipole HF antenna system, leveraging the existing Versa-Tee component. The project details the fabrication of a custom antenna mount from angle aluminum, including specific drilling and tapping for 3/16"-24 bolts, and the creation of radials from Simpson Strong Tie Insulation Supports. It specifies radial lengths for 70 centimeters (6 inches from the center stud) and 2 meters (19 1/4 inches), noting the use of wire nuts for safety. The resource outlines the construction of a mast from 1/2" ID PVC conduit, connected with 3/8"-24 connecting nuts and bolts, mirroring the Buddipole's modular design. It describes the integration of a mobile dual-band antenna with a 3/8"-24 mounting stud and the custom coax setup with BNC and **PL-259** connectors. Field testing with an FT-817ND and a separate dual-band SWR meter confirmed good SWR on both 2 meters and the 440-450 MHz section of 70 centimeters, with positive reception reports during Field Day activities. Further, the article describes the creation of a custom carrying solution, including a 22-inch tripod bag and a fabric roll-up, to emulate the portability of the original Buddipole system.

An interesting presetnation full of usefull tricks to correctly design and build 23 cm Yagi using simple tools. The basic design of the antenna presented in this document is taken from the original DL6WU Yagi Design published in 1982

The antenna in this project is a modification of the techniques used to design a multiband fan type dipole with little or no tuning involved having a total space of 105 feet

Pictures, design plan and description of a 5 element yagi antenna for the 4 meters band by 9A7PJT

Evaluates the **LDG Z100 autotuner**, a device designed to automatically match antenna impedance for optimal transmission efficiency. The review discusses its performance in comparison to the MFJ-902, noting that while the Z100 is a reliable autotuner, it does not match the range of impedances that the MFJ-902 can handle. The Z100 is suitable for operators seeking a 100-watt autotuner that covers HF bands, providing a practical solution for those who require automatic tuning without manual adjustments. The review highlights the Z100's operational context, focusing on its use in HF bands and its practical application in amateur radio setups. While it offers a straightforward tuning process, the Z100's limitations in impedance matching are noted, making it less versatile than some competitors. This comparison provides valuable insights for operators considering an upgrade or replacement for their current autotuner. The Z100's performance is positioned within the broader market of autotuners, offering a clear perspective on its strengths and weaknesses in real-world amateur radio operations.

SWR analysis of an Alpha-Delta DX-LB Plus antenna, configured as an inverted-V with the apex at 40 feet and ends at 15 feet, reveals specific performance characteristics across the HF spectrum. Measurements were conducted using a RigExpert AA54 antenna analyzer, scanning from 0.100 MHz to 54.000 MHz to capture full-range SWR plots. The antenna exhibits notably narrow bandwidths on 80 meters and 160 meters, attributed to its loading coils, necessitating precise tuning for optimal operation within these bands. Conversely, the Alpha-Delta DX-LB Plus demonstrates excellent SWR across the entire 40-meter band, indicating a broad resonance. Performance on 10 meters also shows favorable SWR, though tuning to a desired operating frequency is still recommended for peak efficiency. The article details the methodology and tools employed, building upon a previous "Part 1" analysis of a G5RV antenna, providing a comparative context for antenna evaluation. Practical experience with this multi-band antenna, particularly its loading coil design, highlights the challenges in achieving desired SWR across all bands without specific adjustments. The author's subsequent plans involve replacing the Alpha-Delta DX-LB Plus with a homebrewed 80-40-20-10m parallel **fan-dipole**, aiming for improved resonant characteristics.

The AT-AUTO automatic antenna tuner handles 1.5kW CW operation, employing stepper motors under microprocessor control to precisely position a roller inductor and air-dielectric variable capacitor, avoiding relay-switched discrete components. This design choice prevents loud relay clacking and burning contacts, a common issue with competing products. The tuner features auto-retuning capabilities and receives periodic firmware updates, ensuring continuous improvement and added user-requested features. Its companion product, the _CX-AUTO_ coaxial switch, also features an embedded microprocessor controller. It enables selection of 1-of-8 coaxial outputs via a serial data interface. When integrated with the _AT-AUTO_, the tuner can associate specific coaxial outputs with amateur radio bands, automatically commanding the _CX-AUTO_ to select the correct antenna when the operator QSYs to a different band. Don Kessler began designing the AT-AUTO in 2005, with its debut at the 2006 Dayton Hamvention. Kessler Engineering also offers custom RF product design and electrical engineering consulting, specializing in Class-E RF amplifiers.

Constructing a dip oscillator provides radio amateurs with a fundamental piece of test equipment for resonant circuit analysis. This particular design, adapted by VK3YE from a concept by _Drew Diamond VK3XU_, details a practical build using readily available components. The unit incorporates four plug-in coils, covering a frequency range from **2.6 MHz to 55 MHz**, mounted on 5-pin DIN plugs for versatility. A salvaged two-gang air dielectric variable capacitor, fitted with a vernier reduction drive, serves as the tuning mechanism, with the smaller gang optimizing bandspread at higher frequencies. In practical application, the dip oscillator is used by setting the meter needle to approximately two-thirds scale. When the instrument's coil is brought near a tuned circuit under test, a noticeable dip in the meter reading indicates resonance. This allows for precise measurement of resonant frequencies in antennas, filters, and other RF circuitry, proving invaluable for homebrewing and troubleshooting. The design emphasizes short wire runs for stable operation, particularly at the higher end of its operational range.

Complete collection of the four main parts of this excellet research on modelling and designing half wave dipole antennas for 40 meters band, covering all aspects beginning from full wave length antennas, to shortened, loaded and reshaped dipoles

Antenna Authority Inc. offers a wide assortment of directional, wideband antennas and other equipment specifically engineered for radio direction finding (DFing) and geolocation applications. Their product line includes _log periodic_, _cavity-backed spirals_, and _Yagi_ antennas, alongside covert antenna solutions for various operational requirements. The company emphasizes its expertise in designing and manufacturing specialized antennas for both overt and covert operations. Beyond standard offerings, Antenna Authority Inc. provides custom design services to meet specific client needs, focusing on tailored RF directional products. Their capabilities extend to developing antennas for vehicles and optimizing their operational performance in diverse scenarios. The firm is located at 3381 W. County Line Road, Douglasville, Ga. 30135-1145. Ferrel Bentley is associated with Antenna Authority Inc., which has been operating since at least 2005, as indicated by the copyright notice.

Dubus article about DL6WU long yagi antennas for 23 cm band Article is both in german and english. Yagi antennas are valid alternative to dishes for troposcatter operations. This article explains design and mechanical data for 1296 MHz Yagi Antennas

A great and efficient monoband VHF portable antenna. The article consist of two version of a 12.5 Ohm 3 elements yagi beam antenna plans for the two meter band, a full sized and a shortened version expecially designed for the SSB and CW on 144 MHz.

A light and sturdy Quad for 10 and 15 meters. Basic Quad antenna design considerations. Building and assembling a dual band HF QUAD antenna, designing and joining cross-arms and boom, assembling spreader and element wire installation notes. QST article.