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A 7 MHz vertical half-Moxon array, designed by F6IRF, is presented with its MMANA model, featuring a 20cm gap between the two horizontal elements. The design aims for a low take-off angle, crucial for DX work, and includes specific dimensions for the driven element and reflector, which are constructed from 2mm copper wire. The antenna's feedpoint impedance is approximately 50 ohms, allowing for direct coax feed without a matching network, and it is intended for portable or temporary installations. Field results indicate the antenna provides a **3 dB** gain over a quarter-wave vertical, with a front-to-back ratio of **10 dB** on 40 meters. The author notes successful DX contacts into _VK_ and _ZL_ from France, demonstrating its effectiveness for long-haul communication. The design emphasizes simplicity and portability, making it suitable for operators seeking a directional antenna solution for the 40m band without complex setup requirements.

Ham Radio 20 / 40 meter short Coax Trap dipole antenna designed with the coax trap design calculator program

Presents a comprehensive guide for constructing a broadband Hex Beam antenna, a popular directional array for HF operation. This design offers a compact footprint and excellent gain characteristics, making it suitable for limited space installations while providing significant performance advantages over omnidirectional antennas. The resource details the specific dimensions for a five-band Hex Beam covering 20, 17, 15, 12, 10, and 6 meters, emphasizing the critical element spacing and wire lengths required for proper resonance and pattern. It outlines the construction of the center post, spreaders, and wire elements, along with the feed point assembly, ensuring proper impedance matching. The project aims for a forward gain of approximately **5.5 dBi** on most bands, with a front-to-back ratio often exceeding _20 dB_. Building this antenna requires careful measurement and assembly, but the resulting performance provides a substantial upgrade for DXing and contesting.

A 40 80 dipole antenna design by WA6ESC PDF File

The W1TAG LF Receiving Loop is a specialized antenna project for LF reception, designed to mitigate local noise and enhance weak signal pickup on the lower frequencies. This square loop, measuring 6 feet per side, utilizes 14 turns of #12 THHN wire wound on a PVC frame, offering a robust mechanical structure. The design incorporates a series-tuned circuit with a coupling transformer, allowing for tuning from over 400 kHz down to _45 kHz_ using a switched capacitor bank. Construction details include the use of 1.5-inch PVC pipe for the frame, with specific measurements for spreaders and drilled holes for wire threading. The two 7-turn sections of wire are connected at the center, providing an option for a center tap. The loop rotates on a 1-inch steel pipe, enabling directional nulling of noise sources. The tuning unit, housed in a box clamped to the PVC, employs a 1:2 step-up transformer wound on an _FT-82-77 core_ and uses relays to switch capacitance values from 50 pF to 6400 pF, providing precise frequency adjustment. The current setup connects to the shack via 100 feet of RG-58, feeding into a W1VD-designed preamp, with plans for a balanced, shielded twisted pair cable upgrade.

Engaging in **QRP** operations, where amateur radio transceivers transmit at five watts or less, presents a unique challenge and satisfaction for many radio amateurs. This mode emphasizes efficient antenna systems, keen operating skills, and often, the art of **homebrewing** equipment to maximize performance under power constraints. Operators frequently utilize CW (Morse code) for its superior signal-to-noise ratio, enabling reliable contacts over long distances with minimal power. The VK QRP Club, formally known as the CW Operators' QRP Club Inc., serves as a focal point for Australian amateurs passionate about these low-power pursuits. The club fosters a community where members can share insights on antenna design, circuit construction, and operating techniques specific to QRP. It provides resources such as information on club nets and frequencies, Morse practice materials, and a platform for exchanging ideas among enthusiasts. Membership offers access to a network of like-minded individuals, promoting the continued development and enjoyment of QRP within the amateur radio hobby. The club's activities encourage experimentation and skill refinement, vital aspects of successful low-power communication.

J-Pole Antenna by K4TAX

A homebrew fishing-rod vertical using a very nice design from EB5EKT. This antenna works 20, 30, and 40M bands by selecting the tap points using alligator clips

Located in France, DXBeam designs and manufactures a range of monoband, dual band and triband antennas, rotary dipoles, Moxons and Yagis

Illustrates the construction of a compact _Moxon_ beam antenna specifically tailored for the 40-meter band (7 MHz). The resource details a homebrew project by W7XA, emphasizing its design for limited space while maintaining good bandwidth and directivity characteristics. It highlights the practical application of the _Moxon_ rectangle model to achieve performance on a lower HF band. The primary content is a downloadable PDF document titled "40-Meter-Mini-MOXON-Beam-Antenna.pdf," which provides comprehensive illustrations and technical specifications for replicating the antenna. This includes dimensions, materials, and assembly instructions, making it a practical guide for radio amateurs interested in directional antennas for HF. The project demonstrates how a relatively small footprint can yield a directional antenna suitable for DXing or contesting on 40 meters, a band typically requiring much larger arrays for similar gain and front-to-back ratios. The documentation supports hands-on construction.

This page shows a homebrew vertical antenna based on the Pac-12 antenna design.

This project outlines the construction of a 3-element reversible quad antenna specifically designed for the 40-meter band. The materials required include pushup towers, pressure-treated posts, insulated wire, and various electrical components such as relays and a balun. The construction process is straightforward, beginning with the installation of the posts in a straight line, followed by the assembly of the antenna elements and their elevation to the desired height. The antenna's design allows for directional signal reception, making it ideal for operators looking to enhance their communication capabilities on the 40-meter band. The project includes detailed instructions on tuning the antenna for optimal performance, ensuring that operators can achieve the lowest SWR possible. Additionally, the design can be adapted for other bands by extrapolating dimensions, providing versatility for amateur radio enthusiasts. Overall, this reversible quad antenna project is suitable for both beginners and experienced operators, offering a practical solution for improving signal strength and directionality in 40-meter communications.

Antenna was designed for SO-50 satellite operation but can be used for any VHF/UHF activity. It's a mix of a Moxon Antenna and a Yagi antenna. It has gains 4 dBd on 2m and 6.5 dBd on 70cm bands and it is fed via single 50 Ohm cable.

Why 6 meter hams design the best antennas

A schematic design of the W3DZZ antenna in portugues with description of trap building

The MFJ-940 VERSA TUNER II is a useful little antenna tuner for the HF-bands. However it suffers from a minor design error, which can be easily rectified.

This resource details the construction of a versatile CW/QRSS beacon, designed around a Microchip _PIC16F84_ microcontroller. The project provides a flexible platform for transmitting either standard CW or very slow QRSS signals, making it suitable for LF, VHF, UHF, and SHF applications. It supports two distinct messages, each configurable for speed (from 0 to **127** WPM for CW, or up to **127** seconds per dot for QRSS) and repetition within a six-phase sequence. The core functionality relies on the PIC's EEPROM, which stores all operational parameters, including message content, transmission speeds, phase configurations, and relay control settings. This design allows for parameter modification directly via programming software like _ICProg_ without altering the main program code. The project includes a detailed schematic, a component list, and an explanation of the EEPROM memory mapping for messages, speeds, phase settings, and inter-phase delays. General-purpose outputs (OUT1, OUT2, OUT3) provide dry relay contacts for external control, enabling functions such as power switching, antenna selection, or frequency changes. A 'TRIGGER' input facilitates controlled starts or continuous free-run operation. Sample EEPROM configurations illustrate how to program specific beacon sequences, including message content and relay states.

This is a popular antenna design as the performance is very good across the HF bands and requires little or no tuning. It is a dipole fed off center with a 4:1 current balun at the offset feedpoint. The antenna shown covers 80, 40, 20 and 10 meters with 15 meters and WARC bands

M0VEY shares insights into constructing a 160-meter mobile DX aerial, detailing the process of sourcing materials and assembly. The project began with a goal to avoid a £50 commercial antenna, instead utilizing a £10 reel of _enamelled copper wire_ and salvaged components like alloy tent poles and plastic water pipe. A friend fabricated a custom stainless steel tube for mounting, featuring a 3/8” thread for a mag-mount, enabling secure vehicle attachment. The aerial's design incorporates four alloy tubes, one plastic tube, and a five-foot whip, engineered to split into two pieces for convenient storage. The loading coil, wound with approximately 115 feet of 0.75mm wire onto a plastic former, was then sealed with blue heat shrink. M0VEY reports successful operation, making contacts across the UK and Europe, with the aerial standing about ten feet tall for local nets at 1.972 MHz and taller for the DX window around 1.845 MHz. Future plans include a base-loaded 160m aerial and an 80m version, leveraging components from the existing _160m DX Mobile Aerial_ to maintain a similar overall size with a smaller coil.

The K0RWU 75-meter mobile antenna design features a 7.5-foot overall length, incorporating a 2.5-foot loading coil wound with #20 enamel wire on a 1/2-inch fiberglass rod, subsequently covered with 1/2-inch shrink tubing to increase diameter to 3/4 inch. This configuration achieved resonance at 3965 kHz with a 5-foot stainless steel whip. The antenna integrates a matching transformer, identified by larger turns near the PL259 connector, and is constructed using a modified Radio Shack CB antenna base. Construction involves drilling and epoxying a 1/2-inch fiberglass rod into a PL259 connector, feeding #20 enamel wire through the rod, and winding 17 turns of #18 matching coil wire between the PL259 sleeve and the center feed point. The main loading coil fills the 2.5-foot rod section. The design allows the antenna to bend for garage clearance and emphasizes maintaining a 50-ohm feed impedance to prevent vehicle electrical damage. The author also discusses experiences with a Yaesu ATAS-100 motorized antenna and a 10-meter antenna project, noting issues with auto couplers and the ATAS-100's performance on 17 meters. Future modifications considered include adding a small servo for band spreading and increasing the fiberglass rod length for a 3-foot loading coil to improve bandwidth. The antenna's sharp tuning, between 3960 kHz and 3970 kHz, necessitates careful adjustment of coil turns for optimal VSWR.

The ZS6BKW wire antenna, a variant of the G5RV, utilizes a specific 13m (42.6 ft) length of 450-ohm window line as its matching section, feeding a 28.5m (93.5 ft) flat-top element. This design aims for lower SWR on 40m, 20m, 17m, 12m, and 10m compared to a standard G5RV, often achieving SWR values below 1.5:1 on these bands without an antenna tuner. The feedpoint impedance transformation provided by the window line allows for direct connection to 50-ohm coax on multiple bands. F4FHH's experience involved constructing the ZS6BKW and evaluating its performance against an _OCF dipole_ (Off-Center Fed) on various HF frequencies. The article includes observations on SWR readings and operational effectiveness, highlighting the ZS6BKW's suitability for multi-band operation. The antenna's overall length, including the flat-top and window line, is approximately **41.5 meters** (136 feet), making it a significant wire antenna for fixed station use. Comparative analysis with the OCF dipole provided practical insights into the ZS6BKW's advantages and limitations, particularly concerning bandwidth and tuner requirements.

An home made trapped dipole antenna for 40 and 60 meters band by 2E0HTS

This article describes the design of an antenna for local contacts on 7MHz, including a simple and efficient matching system that presents a 50 ohm load to the transceiver.

Presents the Light Loop, a small magnetic loop antenna optimized for 40m through 10m operation, demonstrating its construction for portable QRP use. The design emphasizes lightweight materials and a compact form factor, making it suitable for handheld or backpack deployment during field activities. It details the primary radiating element, the coupling loop, and the variable capacitor required for resonance across the specified HF bands. The article provides specific component choices, such as the 1.5-inch diameter aluminum tubing for the main loop and the 10-365 pF variable capacitor for tuning. It discusses the importance of precise loop circumference and spacing for efficient impedance matching and bandwidth characteristics. The resource includes practical advice on achieving resonance and optimizing performance for low-power transceivers. Construction notes cover the mechanical assembly, including mounting the capacitor and feedpoint connections. It highlights the antenna's suitability for pedestrian mobile operations, offering a practical solution for HF communication without extensive setup. The design aims for a balance between portability and effective radiation on the lower HF bands.

Demonstrates the iterative design and construction of a **tapped HF/VHF mobile vertical antenna** by K0EMT, detailing four generations of development. The antenna supports operation on 80m, 40m, 30m, 20m, 17m, 15m, 12m, 10m, 6m, and 2m bands. Initial designs, like Generation 1, featured a 3/8" x 24TPI bolt in a PVC end cap with a 1" aluminum tubing mast, resulting in a 9'9" overall length and resonance around 6.9 MHz with the full coil. Subsequent generations refined the mast and coil forms, transitioning from aluminum to copper tubing (Generation 3, found too weak) and eventually fiberglass for the coil form (Generation 4, in progress). Coil tapping points were adjusted to achieve resonance without an external tuner in Generation 2. The project outlines material costs, totaling approximately $25, and mentions a successful 28 MHz QSO with EA3XA using an ICOM IC-706 mk II at 100 Watts. For 80m operation, an external wire with the maximum coil setting is used, or a 56" extender below the coil for stationary use.

Presents the detailed construction of the _FLA25HV_ antenna, a specialized array optimized for Earth-Moon-Earth (EME) communications on the 2-meter band. This resource provides schematics and practical insights into building a high-gain antenna system capable of reflecting signals off the lunar surface, a challenging but rewarding aspect of amateur radio. It covers the mechanical and electrical considerations essential for achieving the precise pointing and signal strength required for successful moonbounce contacts, often yielding **20 dB** or more gain. Amateur radio operators pursuing EME operations require robust antenna systems and precise tracking capabilities. The FLA25HV design addresses these needs by focusing on element spacing, impedance matching, and structural integrity to withstand environmental factors while maintaining critical alignment for lunar reflections. Such systems are crucial for making contacts over distances exceeding **768,000 km**. This personal page serves as a practical guide for hams interested in constructing their own EME arrays, offering a glimpse into the technical dedication involved in pushing the boundaries of VHF/UHF propagation.

A 20-meter Moxon antenna design provides a compact directional solution for the 14 MHz band, achieving approximately **5.5 dBi** of forward gain and a front-to-back ratio exceeding 20 dB. This rectangular wire array, consisting of a driven element and a reflector, offers a smaller footprint than a traditional 2-element Yagi, making it suitable for space-constrained installations. Construction details focus on specific dimensions for the wire elements, fed with 50-ohm coaxial cable. The _Moxon rectangle_ inherently delivers wide bandwidth and a clean radiation pattern, simplifying tuning with a relatively low SWR across the entire 20-meter band. Its robust performance makes it a practical choice for both fixed stations with limited tower space and portable _DXing_ operations. The design's characteristics are particularly beneficial for contesting and long-haul communications on 20 meters.

DAVIS RF Co. has been in the business of supplying the staples of wire antennas for over 30 years. DAVIS RF Co. supply all coax cables, all connectors, ladder line, rotar control cable, insulators, and we have the largest selection of wire for wire antennas. DAVIS RF Co. is the designer and trade mark holder, and primary source for Bury-Flex Tm low loss coax cable. PolyStealth Tm high strength PE insulated antenna wire, and Flex-Weave Tm wire

Details the construction of a **17-meter Moxon Rectangle** antenna, specifically engineered for mounting on a mast beneath an existing beam. The design incorporates insulated wire calculations (0.95804 x generator length) to compensate for velocity factor differences, utilizing readily available materials such as crappie poles for elements, PVC for the boom and mast, and a Budwig HQ-1 dipole connector for the 50 Ohm coax feed. The project outlines a step-by-step assembly process, including mast construction from PVC T-connectors and pipe, element fabrication from crappie poles, and securing elements to prevent droop. Initial testing demonstrated an SWR of 1.3:1 on 17 meters, achieving a 5-8 signal report into Texas with 100 watts. Subsequent reinforcement and elevation of the antenna resulted in a 15 over 9 report from Florida. Comparative testing against an 88-foot center-fed Zepp antenna indicated superior performance, with the Moxon consistently outperforming the Zepp and receiving signals the Zepp could not. A notable DX contact with JA8NFV in Hokkaido, Japan, yielded a 5-9+ signal report both ways using 100 watts.

This resource details the construction of a mobile screwdriver antenna, patterned after the original W6AAQ DK3 design from 1991. It covers the mechanical and electrical aspects of building a robust, multiband HF antenna for vehicular operation. Specific components discussed include the lower mast section, the coil wound on Schedule 40 PVC pipe, beryllium copper contact fingers, the motor drive assembly utilizing a Black & Decker screwdriver, and the capacity hat design with a brass hub and steel wires. The article provides insights into material selection, such as heavy copper tubing and silicone grease for assembly, and addresses practical considerations like coil length limitations for 80m operation due to lathe size. The construction results in an antenna capable of tuning from 6.5 MHz (40m) up to 6m, with slightly reduced range when the capacity hat is installed. The author describes the mounting base with soldered brass nuts for secure attachment and a U-channel bracket for vehicle mounting on a Dodge Ram 1500. The article includes close-up photographs illustrating the coil, contact fingers, drive mechanism with rubber tubing clutches, and the capacity hat assembly. It also mentions the use of Rustoleum hammer finish enamel for painting the copper pipe, indicating attention to durability and aesthetics.

Based on DL6UW Yagi antenna's design-formula The forward gain is 13.6 dBi (about 11.5 dBd) and it's pretty small, about 1,5 m in length

Fractal Antennas are a new generation of multiband antennas for wireless communications. Based on a new design concept, fractal technology.

Long Waves, Short Antennas, designing antennas for MF and LF communications

Demonstrates the construction of two distinct wideband RF preamplifiers, detailing their component requirements and performance characteristics. The first design leverages monolithic microwave integrated circuits (MMICs) such as the MAR-6, MAR-8, or PGA103, offering a broad frequency response from DC to 2 GHz with a gain of 22.5 dB at 100 MHz and a noise figure typically below 3 dB. This MMIC-based amplifier incorporates protection against power supply transients and features a 50 Ohm input/output impedance, operating from an 8-20 volt supply with low current drain. The second preamplifier design utilizes a BSX-20 transistor, providing amplification across the 14 MHz to 550 MHz range. This simpler, more economical build achieves an average gain of 12 dB at 145 MHz and a noise figure of approximately 1.1 dB. It operates from a 7-15 volt battery supply with a current draw of 6 mA. Both projects emphasize critical construction techniques, such as maintaining short RF connections, ensuring 50 Ohm impedance paths, and mounting the circuit within a shielded enclosure to optimize performance and minimize noise. The resource also discusses phantom power options for antenna-mounted preamplifiers and precautions for use with transceivers, including output protection diodes and static bleeders.

Constructing a high-gain, compact antenna for 2 meters often involves balancing theoretical performance with practical build challenges. WB8AHT recounts his journey in building a 6-element _Super Duper Moxon_ antenna for 144 MHz, inspired by designs from M0PXS and GW3YDX. He initially encountered discrepancies in published dimensions for the _HAARP Antenna_ and the _Super Moxon_, leading to on-air SWR issues and suboptimal performance. His methodical approach involved cross-referencing, direct communication with Phil Simpson (M0PXS), and iterative adjustments to element lengths based on observed results and a _SARK-110 Antenna Analyzer_ scan. After modifying the reflector/driven element and third director dimensions, the antenna achieved a respectable 1.35:1 SWR at 144.200 MHz. Field testing with 50 watts yielded contacts up to 500 miles, suggesting performance close to the 15 dBi gain predicted by _4NEC2_ software, despite its compact 40-inch boom. The article includes specific construction notes, such as tubing sizes (1/2-inch and 3/8-inch aluminum) and feedpoint spacing (50mm). The author's experience highlights the importance of real-world validation for antenna designs, even those with strong theoretical backing. He provides a table of tubing lengths for 6m, 4m, and 2m versions, along with his final, optimized dimensions, offering a practical blueprint for fellow hams interested in replicating or further experimenting with this high-performance, small-footprint VHF antenna.

Here is an antenna for the nineties. It's strong, computer designed, and has lots of gain. It is a full size, four element beam on 10, and three elements on 15 meters

The QRP choke balun described utilizes a high permeability ferrite rod and RG-174 coax, aiming to present high impedance to common-mode currents across the HF spectrum. The construction involves winding as many turns of RG-174 as possible around the ferrite rod, then encapsulating the assembly with hot glue. This design prioritizes maximizing inductance to suppress unwanted shield currents, particularly in unbalanced antenna configurations. While the balun's effectiveness is subjectively reported as good, a potential design consideration involves the dielectric properties of the hot glue. This material could increase turn-to-turn capacitance, potentially reducing the balun's performance at higher HF frequencies, though this specific aspect has not been formally tested by the author, _AA5TB_. The project serves as an illustrative example of a practical, junk-box construction rather than a rigorously engineered solution. Photographs detail the evolution of the balun, from the initial winding process to its integration within a _B&W dipole center insulator_ and final camouflaged assembly.

Over **10 million** antennas and flags have been sold worldwide by Firestik Antenna Company, a veteran-owned manufacturer specializing in both CB and amateur radio communication products. Their offerings include a range of antennas, mounting accessories, and coaxial cables, designed for various mobile and fixed applications. The company provides technical support and maintains a network of dealers for product availability. Firestik products are known for their fiberglass construction, which is evident in their _Firestik_ and _Firefly_ antenna lines. The company also produces unique items like the "342 mile per hour Firestik flag," highlighting their diverse manufacturing capabilities beyond just radio antennas. They emphasize their commitment to quality and customer service, including direct technical assistance. The company is located in Tempe, Arizona, and operates under the registered trademark of _Pal International Corporation_. They actively protect their brand, including variations like Firestick and Firestix, ensuring proper representation of their products in the market.

A half-sized Hentenna designed for unique performance in compact spaces. Initially built in 2003 for monitoring a local 146.97 MHz repeater from a basement shop, the antenna proved highly effective, operating at just 200mW. In 2005, it was adapted for use in a challenging river-bottom location, delivering reliable performance on a 2-meter band with 5W. Despite its compact size, the Forktenna demonstrated excellent results compared to a full-sized Hentenna, making it an intriguing option for many hams.

The resource provides an in-depth analysis of the W6NL 40m _Moxon Yagi_ antenna, utilizing a NEC-2 model to simulate its performance. It details the antenna's design parameters, including element lengths and spacing, and explores critical operational aspects such as feedpoint impedance, SWR across the 40-meter band, and radiation patterns. The document systematically presents the model's setup and the methodology for evaluating the antenna's behavior in different environments, including free space and over real ground. Performance data derived from the NEC-2 model illustrates the antenna's forward gain, front-to-back ratio, and beamwidth. For instance, the model predicts a free-space gain of approximately **6.5 dBi** and a front-to-back ratio exceeding **20 dB** at resonance. Comparisons are drawn between free-space performance and operation at various heights above average ground, demonstrating the impact of ground proximity on take-off angle and overall efficiency. The analysis also touches upon the antenna's bandwidth characteristics, indicating its suitability for the entire 40-meter band with acceptable SWR.

An homebrew crossed Yagi antenna for two meters band based on DK72B design with pictures, detailed description and tricks by Barry Zarucki M0DGQ

An Active antenna designed for VLF and shortwave radio reception. A small antenna capable of excellent performances on low bands, made on a copper plate and introductio to active antennas.

Helical antennas invented by John Kraus give a circular polarized wave. They are one of the easiest to design. Find a tube with a circumference equal to one wavelength, and wrap wire in a helix spaced a quarter wavelengt

This is a 200 Watt PEP step up transformer for end fed full and half wave antennas without radials, designed as a 200 Watt PEP

Presents the construction and performance characteristics of a **2-meter vertical Moxon** antenna designed by WB5CXC. The antenna utilizes 1/2-inch PVC and #6 copper ground wire for its physical structure. Performance data includes measured front-to-back ratio using a local repeater, demonstrating significant signal attenuation when rotated. The resource provides **antenna pattern** plots, with blue tracing the design at 146 MHz and red indicating performance at 148 MHz. Gain and SWR plots are also included, alongside a detailed diagram of the antenna's physical layout. The design emphasizes a good front-to-back ratio, aligning with modeling predictions.

Designing **Moxon Rectangle** antennas often involves an urge among builders to find simple "magic formulas" for element lengths. L. B. Cebik, W4RNL, argues against this simplistic approach, emphasizing that antenna dimensions do not scale linearly and are influenced by factors like wire size and height above ground. This resource presents a procedure for developing sensible design equations, starting with uniform-diameter elements and perfectly conductive materials, with adjustments for real-world materials like copper and aluminum. The core of the method involves judicious **NEC modeling** (versions 2, 3, or 4) to create a baseline dataset for regression analysis, ensuring models meet specific performance standards for gain, front-to-back ratio, and feedpoint impedance. The derived equations, presented as a BASIC program, allow for calculating Moxon dimensions (A through E) based on wire diameter in wavelengths and design frequency. W4RNL demonstrates the efficacy of these equations by designing and testing Moxon Rectangles for 7.15 MHz (AWG #12 wire), 28.5 MHz (1" tubing), and 146 MHz (0.125" rod). Modeled performance data, including gain, front-to-back ratio, and feedpoint impedance, are provided for both perfect and real-world materials, showing high efficiency and close adherence to design goals. The article also references a standalone Windows program by AC6LA that automates these calculations and generates EZNEC or NEC models.

Operating a ZS6BKW antenna often involves understanding its lineage from the _G5RV_ design, with specific modifications by ZS6BKW to optimize performance on several bands. Through computational analysis and field measurements, the antenna's dimensions were refined to allow operation on 10, 12, 17, 20, and 40 meters without an antenna tuner. For 80, 30, and 15 meters, a tuner is necessary, though efficiency on 30 and 15 meters is noted as not particularly high. The physical configuration consists of two 13.755-meter radiating elements fed by a 12.20-meter section of 450-ohm ladder line. Tuning the antenna on the 20-meter band is critical, and any deviation in the ladder line's characteristic impedance necessitates recalculating the element lengths. The design is also referenced in the 12th edition of _Rothammel's Antennenbuch_, page 219. Proper common mode current suppression is crucial at the transition from ladder line to coaxial cable. This can be achieved with a common mode choke, such as several turns of coax wound into a coil or over a ferrite toroid like an Amidon T130. While a 1:1 balun is an option, it may introduce issues.

A vertical antenna specifically designed to work with the 80 meter CW beacon keyer

A _Topfkreis_ antenna, also known as a "bicycle pump" antenna, is presented as a simple vertical design for the 70 cm band. This variant of the J-pole antenna is notable for not requiring a ground plane, simplifying deployment. The construction details specify using aluminum tubing for the radiating element, with precise measurements for the quarter-wavelength outer tube (32 mm diameter) and the three-quarter wavelength inner sliding tubes (10 mm and 8 mm). Feeding is via a 50-ohm coaxial cable connected 90 mm from the base of the central tube. This design can achieve a gain of **4 to 6 dB** when properly tuned using the adjustable radiating element. The article details the fabrication of a critical aluminum washer, suggesting a method using a hole saw and a drill press as a lathe for precise adjustment. The illustrated example is specifically for the 70-centimeter band, and the author, Pop, clarifies construction points in the comments, including material choices and assembly techniques, ensuring a robust build for VHF/UHF operation.

A 90-foot vertical antenna constructed from **aluminum irrigation tubing** is detailed, focusing on its innovative raising and lowering mechanism. The resource describes a **45-foot ginpole** system, allowing a single operator to erect or lower the antenna in minutes. It covers the mechanical design, including the pivot base, insulated joints for the tubing sections, and guy wire attachment points. The antenna consists of two 30-foot sections of 4-inch tubing and one 30-foot section of 2-inch tubing, stacked with the smaller diameter at the top. The electrical design incorporates PVC "condulet" boxes at the 30-foot and 60-foot points, housing relays to change the effective height for multi-band operation on 160, 80, 40, and 30 meters. Ferrite rod inductive chokes are used for DC control and to tune out gap capacitance. The antenna is fed with 1000 feet of open wire line, connected to a matching transformer comprising stacked toroids and a coaxial/toroidal balun. Grounding is achieved with a 3x3 foot grid of 16-gauge tinned copper wires with soldered crossovers.