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Design your VHF UHF Yagi antenna online, a JavaScript enhanced web page that implements the design of an antenna for 2m and 70cm bands. This page offers a streamlined experience for Yagi antenna design enthusiasts. It assumes prior knowledge of Yagi design principles, minimizing distractions with a user-friendly interface. Equipped with essential equations, it provides instant design feedback. Red font warnings indicate design limitations, ensuring practical results. Constraints include Gain (11.8-21.6 dBd) and Boom Length (2.2-39 wavelengths), with additional frequency-dependent restrictions noted in input fields.

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Build a space efficient trapped dipole antenna for 40-80-160 meter bands using RG-58 and PVC pipe. The document provides a brief guide on building a compact dipole antenna appropriate for the 40, 80, and 160-meter amateur radio bands. It explains the materials, building processes, and tuning methods required to provide best performance while preserving space. The paper also discusses theoretical elements of dipole antennas, such as impedance matching and feedline selection.

A 10-20 meters coverage delta loop antenna. After relocating, DL2HCB designed a multiband loop antenna to cover 10-20m with an open-wire feed for impedance matching and compact installation. Inspired by the mini-X-Q design, a modified 10m delta-loop was built, enhanced with a 1/4 wave shorted stub for 28 MHz using 450-ohm ladder line. The antenna delivers east-west broadside radiation and performs as a closed loop on other bands. Operational tests yielded strong European signals and successful DX contacts, including a 20m QRP QSO with FY/DJ0PJ.

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.

Demonstrates the construction of **magnetic loop antennas**, detailing both multi-turn and single-turn designs. It covers a 30-inch diameter multi-turn loop for 80 meters, based on a February 1996 QST article, and an octagon single-turn loop made from 15mm copper tube with a 4.8-meter circumference, operating from 7 MHz to 14 MHz. The document also presents a smaller 800mm diameter loop for 14 MHz to 28 MHz, emphasizing the importance of high-voltage tuning capacitors. Covers the design and construction of custom **butterfly capacitors** and piston capacitors, including a split stator capacitor with 140 pF capacitance and a 6000 Volt rating, and a butterfly capacitor with 5-65 pF and 7200 Volt rating. It explains why butterfly capacitors are preferred over split stator types for high power applications due to lower losses and direct series connection of rotors, reducing resistive losses from wiper contacts. Material recommendations include clear PVC for plates and brass or stainless steel for non-magnetic hardware. Addresses practical considerations such as feeding the loop with a shielded 1/5 Faraday loop made from RG213 or RG8 coax, achieving VSWR 1.1 across bands, and optimizing its placement 180° from the capacitor. It also discusses mechanical joint resistance, dissimilar metal oxidation prevention using Vaseline, and a simple method for determining radiation angle with a TL-light tube. The guide includes diagrams for rotor, stator, and end plate construction.

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

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

A balun is a device that is used at the feedpoint of a balanced antenna when an unbalanced feedline is desired to feed the antenna. Balun is a contraction for BALanced to UNbalanced.

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.

160 meter linear loaded voltage fed T antenna

The RXO Unitenna, a vertical wideband antenna, offers operation across the 7-21 MHz spectrum, covering the 40, 30, 20, 17, and 15-meter amateur bands. This design focuses on achieving a low SWR across a broad frequency range, making it suitable for general HF operation without requiring an external antenna tuner for minor SWR variations. The antenna utilizes a unique loading coil and matching network to maintain efficient radiation characteristics across its operational bandwidth. Construction details within the PDF document include specific dimensions for the radiating element and the counterpoise system, which is critical for vertical antenna performance. The design incorporates readily available materials, simplifying the build process for radio amateurs. Performance graphs illustrate the SWR characteristics across the 7 MHz to 21 MHz range, demonstrating the antenna's wideband capabilities. The document also provides guidance on feedline connection and grounding considerations for optimal field deployment. This vertical antenna configuration is particularly useful for hams with limited space, offering a compact footprint compared to horizontal wire antennas.

Determining the actual need for an antenna tuner often hinges on the specific antenna and feed line configuration in use. While many hams believe a tuner is always essential, its primary role is to present a 50-ohm impedance to the transceiver, not to "tune" the antenna itself. For instance, a resonant dipole fed with _coaxial cable_ at its design frequency typically requires no tuner, as the feed line impedance closely matches the radio's output. However, operating a non-resonant antenna, or using a resonant antenna on multiple bands, frequently necessitates a tuner to manage high Standing Wave Ratio (SWR) on the feed line. The article clarifies that a tuner placed at the transceiver only matches the radio to the feed line, not the antenna to the feed line. For maximum efficiency with a non-resonant antenna, an _automatic antenna tuner_ (ATU) or a remote tuner placed at the antenna feed point is often more effective, minimizing losses in the feed line. The discussion also touches on the practical implications of SWR, noting that modern transceivers often fold back power at high SWR, making a tuner a practical necessity to achieve full output power, even if the antenna itself is not perfectly matched.

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

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

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

This drawing shows a simple 10 meter wire J-pole antenna designed for 28.4 MHz. It is a vertical, end-fed Zepp-style antenna made from common materials and intended for easy home construction. The main radiating element is a straight length of stranded copper wire, either 14 or 18 gauge, cut to about 16.5 feet. At the top, the wire is supported by an insulator, allowing the antenna to be hoisted vertically. The matching section is made from 450-ohm ladder line, approximately 7 feet 9.5 inches long, and shorted at the bottom. This matching stub transforms the impedance so the antenna can be fed with coaxial cable. The feed point is tapped about 6 inches above the bottom of the stub, with the shield and center conductor connected at the proper points. A choke balun is formed with five turns of RG-58 coax in a 4-inch diameter loop to help reduce unwanted RF on the feed line. The drawing notes that this antenna has about 0 dBd gain, similar to a dipole, but offers an omnidirectional pattern and low-angle radiation when installed high. Its main advantage is practical performance, simple construction, and effective coverage for 10 meter operation.

Demonstrates the construction and on-air performance of the _NB6Zep_ antenna, a modified 20-meter Extended Double Zepp design optimized for multi-band operation from 40 through 10 meters. The resource covers basic design principles, including dimensions of 66 feet horizontal and 5 feet vertical elements, and specifies open ladder line or TV twin lead for the transmission line. It details material selection for low-cost wire antenna construction, such as 18 AWG wire for the legs and ceramic or plastic insulators, along with practical tips for soldering connections and insulating against moisture. The author, NB6Z, shares insights from extensive _EZNEC_ modeling to optimize the antenna's total length for a 40-meter half-wave dipole footprint and feed line length for direct tuner connection. The article presents field results, including successful _PSK31_ contacts from Oregon to the East Coast on 40 and 30 meters with 50 watts, even at a low height of 6 feet. It provides detailed performance characteristics for each band, noting the _NB6Zep_'s highest gain (over 3 dB) and sharp, medium-angle lobes on 20 meters, which yielded strong DX reports to locations like Korea, Japan, and Argentina. For 17 and 15 meters, it describes a butterfly-like pattern with broad lobes, while 12 and 10 meters exhibit narrow, directional lobes in an "X" configuration. The author also shares personal experiences operating successfully for over a decade in an antenna-restricted environment using the NB6Zep and other stealth wire antennas.

The Double Bazooka Dipole is a very efficient single band antenna which is very quite, and does not require the use of a balun. This antenna consists of coax (RG58) or other 50 ohm type with the shield split at the center and the feedline attached to the open ends

Demonstrates the construction and performance of an updated ZS6BKW multiband dipole, a variant of the _G5RV_ antenna, specifically designed for HF operation. The article details a real-world installation using 13.5m copper wire elements and 12.2m of 450 Ohm ladder line, configured as a sloping inverted-V with the apex at 10m and ends at 4m above ground. It covers the critical aspect of impedance matching, incorporating an 8-turn choke balun at the feedline transition to RG-58U coax to mitigate RF common mode current. Measurements confirm favorable SWR readings below **1.3:1** on 7.1 MHz, 14.11 MHz, 18.06 MHz, and 24.8 MHz, indicating effective resonance across 40m, 20m, 17m, and 12m bands. The installation also shows usable SWR dips on 3.55 MHz (5:1), 29.02 MHz (2:1), and 50.84 MHz (3:1), extending its utility to 80m, 10m, and 6m with an antenna tuning unit. Initial on-air results report clear reception of stations over **5000km** away, validating its DX potential.

The Windom is an Off-center wire multiband Antenna. The old version was fed just by a single-wire connected on 1/3 of antenna's overall length or with an open-line feeder (later versions). Here is another model with coaxial feeder, which is compatible with Solid States - 50 Ohm output transceivers .

Selecting an appropriate antenna system for shortwave broadcasting involves evaluating various types based on performance, cost, and operational parameters. This resource details the critical specifications for broadcast antennas, including average and peak power ratings, directivity, takeoff angle (TOA), horizontal beamwidth, and gain, emphasizing that a 100-kW transmitter requires an antenna rated for 150 kW average and 400 kW peak. It clarifies that low TOA signals travel thousands of kilometers, while high TOA is for local coverage, and nearly all modern shortwave broadcast antennas are horizontally polarized. The article explores specific antenna types, such as Log-Periodic Antennas (LPAs), which offer wide frequency ranges (e.g., 2-30 MHz) and directional patterns with 11 dBi gain, costing from $20K to over $100K for multi-curtain versions. Dipole arrays, also known as curtain antennas, are prevalent in international broadcasting, featuring steerable beams (±15° and ±30°) and mode-switching capabilities to alter TOA, with high/low pairs costing over $1 million. Fan dipoles are noted for omnidirectional patterns, smaller size, and lower cost for low-power applications, while rhombics, though simple, require resistive termination and incur several dB of I2R losses. Balun considerations are crucial, as most communications baluns are not rated for the higher average and peak powers of AM broadcast transmitters. Modern shortwave antennas utilize durable materials like Alumoweld wire rope for radiators and support elements, avoiding copper, fiberglass, or materials prone to stretching or deterioration. Feeder systems for high-power stations often require tapered-line baluns to convert 50-ohm unbalanced power to 300-ohm balanced for connection to the antenna.

The 30/40 meter **vertical antenna** project by IK4DCS details the construction of a shortened, self-supporting design, reaching a total length of 5 meters. The antenna incorporates a linear loading section and a coaxial cable trap for 30 meters, based on the "Antenne Volume 2°" text by Nerio Neri (page 223). The design uses six radials, three for each band, positioned at approximately 90° inclination and at least one meter above the roof or ground, connected via a 1:1 balun at the feed point. Mechanical construction utilizes aluminum tubing, with a 2.30-meter primary radiator section (30 mm diameter) joined to a second part using a Teflon insert and a PVC sleeve for rigidity. The linear load, approximately 3.70 meters long, accounts for a 30% physical shortening of the quarter-wave element. A capacitive load, made from three 50 cm radials, is integrated into the 40-meter top section for fine-tuning. Final adjustments involved radial inclination for 40 meters, as initial testing showed increased SWR and interference on 30 meters due to nearby resonant structures. The author emphasizes the importance of clear space for optimal performance and provides drawings and photos to clarify the build process.

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.

The document is a PDF detailing the construction of the DBJ-1 VHF-UHF Dual Band J-Pole antenna for amateur radio use. It provides instructions on how to build a high-performance dual band base antenna for VHF and UHF bands using a single feed line for less than $10.

Demonstrates an online **CW** audio decoder tool, currently under active development, designed for analyzing and decoding Morse code. Users can upload audio files containing Morse code or record live audio input via a microphone, with processing handled entirely in JavaScript using the Web Audio API. The software analyzes the audio, attempting to determine the pitch and speed, and then decodes the message, providing options to compare the decoded output against a predefined message or a perfectly timed version. The interface allows for setting optional comparison messages, character speed in WPM, and Farnsworth speed. It also features interactive charts for visualizing the audio analysis, where users can zoom with the mouse wheel and pan by dragging. Specific buttons highlight different element types such as intra-character space, inter-character space, extra elements, missing elements, and replaced elements, aiding in detailed signal analysis. Built-in test files are available for immediate analysis, allowing users to quickly evaluate the decoder's performance. The tool is noted to work with specific browsers and is presented as a testing platform for user feedback, indicating ongoing refinement of its decoding algorithms and user interface.

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.

Presents G0GSF Brian's ZS6BKW antenna, a refined iteration of the classic G5RV, offering improved performance across multiple HF bands. The design emphasizes specific radiator and ladder line lengths to achieve lower SWR on 40m, 20m, 17m, 12m, and 10m, making it a practical choice for operators seeking a single wire antenna solution. The document includes critical dimensions for the flat-top and the 450-ohm ladder line section, which are key to its multiband resonance characteristics. Unlike the original G5RV, the ZS6BKW aims for direct 50-ohm feedpoint impedance on several bands, reducing the need for an external antenna tuner. My field experience with similar optimized dipoles confirms that precise construction, particularly the ladder line length, is paramount for realizing the intended SWR benefits. This design offers a compelling alternative for hams with limited space or those preferring a less complex antenna system.

A 2-meter Turnstile antenna, detailed for amateur satellite communication, offers a straightforward build for those looking to engage with orbiting transponders. The author, WB8ERJ, shares his personal design and construction methods, emphasizing the antenna's simplicity and effectiveness for LEO (Low Earth Orbit) satellite work. This design provides a circularly polarized signal, crucial for mitigating _Faraday rotation_ and signal fading often encountered with linearly polarized antennas when tracking satellites. Construction involves readily available materials like PVC pipe and copper wire, making it an accessible project for many hams. The article includes practical advice on element spacing and feed point considerations, drawing from the author's hands-on experience in the shack and field. It highlights the antenna's utility for receiving signals from various amateur satellites, including the popular AO-91 and AO-92. The Turnstile's inherent omnidirectional pattern in the horizontal plane, combined with its circular polarization, yields consistent signal reception, often resulting in **stronger decodes** and **more reliable contacts** compared to basic dipoles or verticals.

A 40-meter reversible _Moxon rectangle_ antenna project details its construction and performance, featuring 51-foot long sides and 7.7-foot turned-in sections. The design incorporates a 16.5-foot boom, with elements spaced 1.1 feet apart, constructed from #14 covered wire. It utilizes two double-pole relays for switching between NE and SW directions, achieving F/B ratios up to 40 dB on CW and 30 dB on SSB, with distinct reflector stub settings for each mode. This antenna replaced a full-size 2-element Yagi, demonstrating comparable forward gain while offering superior F/B ratios and directional flexibility. _EZNEC_ modeling indicates only 0.2 dB less forward gain than the Yagi. The system uses no baluns, relying on half-wave feedlines and switched stubs for impedance matching. The antenna is tree-supported at 45 feet, with its effective radiation height modeled at 80 feet due to local terrain, enhancing its performance over a nearby lake.

A Center-Fed Half-Wave Dipole is probably the simplest of antennas to construct and use. It is usually suspended between two supports, from it's end insulators, and has the feedline hanging from the center.

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.

One of the best antenna values on the market is the LightningBolt Quad. At about half the cost of a tri-band yagi, you get five band coverage with a single coax feedline and excellent performance from a light, low wind load antenna.

This project is intended to aid in tuning a balanced antenna or feedline that has a high impedance 100-600 ohms

RF Choke to prevent hf currents on the feedline. This Magnetic Longwire Balun (MLB) makes it possible to efficiently use a coaxial lead-in cable with all forms of longwires, T-forms or other types of wire antennas, without the need for an antenna tuner.

The Super J Pole antenna is a co-linear vertical consisting of a number of half wave length vertical elements separated with half-wave length stubs (Tuning stub) feed with a folded matching stub by vk6ysf

The document details the optimization and construction of the _Maria Maluca_ antenna, a compact 6-band (20m-6m) directional beam. It presents a comparative analysis of shortwave antenna principles, highlighting the efficiency gains achieved by using an open feeder line and tuner as a resonant unit, contrasting this with the losses associated with traps or capacitive loads in multiband antennas. The resource specifically revisits an older South American 2-element design for 10, 15, and 20 meters, applying modern NEC-based software to develop a six-band version. Performance data is meticulously tabulated, showing impedance, free space gain, gain at 12m height, elevation angle, and front-to-back (F/B) ratio for each band from 20m through 6m. For instance, on 15m, the antenna achieves 5.1 dBd free space gain and 13.72 dB F/B ratio. The construction section provides practical guidance on element assembly using aluminum pipes and hose clamps, detailing the use of a heavy-duty glass fiber reinforced polyamide rod for electrical separation and bending strength. It also specifies the use of 450-ohm _Wireman_ line CQ 552 for the transmission line. The document includes diagrams for rod fixing, an air-wound balun, and a vertical elevation diagram for the 15m band, illustrating its DX qualification. It also discusses the antenna's suitability for portable and expedition operations, noting its compact transport dimensions (max 1.50m length, 12 lb weight) and quick assembly time (under 15 minutes). The author, Dipl.Ing. Helmut Oeller, DC6NY, is identified as a source for material kits.

The G5RV antenna, a popular multi-band wire antenna, typically employs a center-fed design with a specific length of 300-ohm or 450-ohm open-wire line acting as an impedance transformer, feeding a coaxial cable run to the shack. Its overall length for 80-10 meters is approximately 102 feet (31 meters) for the flat-top section, with a 34-foot (10.36 meter) matching section. The original design by Louis Varney, G5RV, aimed for efficient operation on 14 MHz (20 meters) as a 3-half-wave antenna, with the matching section providing a good match to 50-ohm coax on that band. While the G5RV offers multi-band capability, its performance varies across bands, often requiring an antenna tuner for optimal SWR on bands other than 20 meters. The matching section's length is critical for its impedance transformation properties, influencing the feedpoint impedance presented to the coaxial cable. Variations like the G5RV Junior and ZS6BKW utilize different flat-top and matching section lengths to optimize performance for specific band sets or to achieve a lower SWR without a tuner on certain bands, demonstrating the adaptability of the basic G5RV concept.

RF Choke to prevent hf currents on the feedline or...1:1 Choke Balun, sometimes called the "UGLY BALUN"

An antenna system is more easily interfaced to a radio when the input reactance at the feedline terminals is low or close to series resonance

This resource details the computer-optimized design of the _ZS6BKW_ multiband dipole, an evolution of the classic _G5RV_ antenna. It begins by referencing the original 1958 RSGB Bulletin article by Louis Varney G5RV, explaining the operational principles of the G5RV's flat-top and open-wire feedline on 20m and 40m, noting its impedance transformation characteristics for valve amplifiers of that era. The article then transitions to the rationale for optimizing the design for contemporary solid-state transceivers requiring a 50 Ohm match. The core of the project involves using computer modeling to determine optimal lengths for the flat-top and matching section, aiming for a VSWR of less than 2:1 on multiple HF bands. It discusses the process of calculating feedpoint impedance based on antenna length and frequency, referencing professional literature from Professor R.W.P. King at Harvard University. The analysis also considers the characteristic impedance (Z(O)) of the open-wire line, identifying a broad peak of adequate values between 275 and 400 Ohms. Specific design parameters for the improved ZS6BKW are presented, including a shorter flat-top and a longer matching section compared to the original G5RV, with a velocity factor of 0.85 for the 300 Ohm tape. The article confirms acceptable matches on 7, 14, 18, 24, and 28 MHz bands when erected horizontally at 13m, and also discusses performance in an inverted-V configuration, noting frequency shifts. The author, Brian Austin ZS6BKW, emphasizes the antenna's suitability for modern 50 Ohm coaxial cable without a balun.

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.

Put up the longest dipole you can fit, feed it with open wire line, connect it to the balanced output of your tuner and poof! Instant multiband antenna. Is life really that simple?

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.

A multiband wire antenna with a twinlead feedline that can be easily tuned in several bands, witha 33 ft per leg you can have a 40 to 10 meters band coverage

The Classic Multiband Dipole Antenna QST article. The open-wire feed line dipole antenna is easy to install and offers surprising performance on several bands. You can install it in almost any configuration; it does not have to be strung in the traditional horizontal flat top

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