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Design your own antenna trap online

Program that produces antenna radiation patterns and graphs for SWR, forward gain, and F/B ratios

The project details a DIY SWR/Wattmeter designed around an _Arduino Uno_ shield, providing capabilities to measure RF power from 2 to **200 watts** and Standing Wave Ratio (SWR) for HF amateur radio bands. This construction features a compact design, integrating the measurement circuitry directly onto a custom PCB that interfaces with the Arduino Uno microcontroller. Key components include a directional coupler for sensing forward and reflected power, precision rectifiers, and analog-to-digital conversion for processing RF signals. The Arduino firmware handles calibration, calculations, and displays the results on an integrated LCD, offering real-time feedback on antenna system performance. The design prioritizes simplicity for homebrewers. Performance specifications indicate accurate readings within the **2-200W** power range, suitable for typical QRP to medium-power HF operations. The project provides schematics and a basic overview of the software logic.

This is the antenna w3ff designed for his walking portable station. It is a dipole constructed out of the plastic plumbing pipe CPVC. There are telescoping whips at the ends of each side of the dipole, and these whips are adjusted to bring the antenna into resonance on each of five HF Bands 10, 12, 15, 17, and 20 Meters

Two well performing 50 MHz antennas designed with W7EL EZNEC along to many other antenna projects and related articles

NGC is now distributor for COMET and MALDOL brand antenna products designed, manufactured in Japan. Distributor of DAIWA brand RF SWR/power meters and switching power supplies, antennas, test equipment, antenna analyzers and more

The HB9ABX RoomCap antenna document details the construction and performance characteristics of a compact HF antenna design. It presents a series of comparative field tests conducted between July and September 2005, evaluating the HB9ABX antenna against established designs like the Microvert MV-500, Cushcraft R5/R7000 verticals, and a 5-element DJ2UT Yagi beam. Specific test scenarios include mobile installations, rooftop deployments, and comparisons on 20m, 40m, 80m, and 160m bands, with signal reports from various European and DX stations. The resource emphasizes the antenna's small physical footprint and its claimed efficiency across multiple HF bands. Test results consistently show the HB9ABX antenna performing comparably to, and often outperforming, larger reference antennas in terms of received signal strength, with reported differences of 1 to 2 S-points (6-12 dB) in many contacts. Notably, a 20m DX test on July 26, 2005, indicated the 1.3m HB9ABX radiator yielded 2-3 S-points stronger signals than an R7000 vertical for US DX stations. An August 12, 2005, test on 40m highlighted the HB9ABX's superior signal-to-noise ratio in urban QRM, demonstrating 10-18 dB better performance than an R7000. The document includes specific callsigns, signal reports, and QTHs for each comparison, providing empirical data for the antenna's performance claims.

This Vertical antenna design by David Reid for lower bands focuses on achieving effective DX communication by optimizing the antenna low-angle radiation for long-distance contacts. The design incorporates techniques like linear loading and capacity hats to reduce the antenna's height while maintaining performance, especially on 40m and 80m bands. Building a solid ground plane and using quality materials ensure efficiency and durability. Although vertical antennas can be complex to build, this project simplifies the process, making it accessible for ham operators seeking strong, reliable signals.

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

J-pole Design Program V1.1 by WA2ISE Download a VHF twinlead Jpole antenna calculator MSDOS program

"Some have called the T2FD a ""squashed rhombic"" antenna. It does bear some design similarities to the non resonant rhombic, but theoretically it is admittedly inferior. However, the T2FD performs well in a modest amount of space."

Details the construction and optimization of antenna systems for amateur radio satellite operations, focusing on practical, homebrew solutions for VHF/UHF bands. It covers building _groundplane antennas_ from salvaged materials, recycling old beam antennas into new configurations like a 2-meter crossed yagi, and constructing a 10-meter horizontal delta loop. The resource also explains antenna matching techniques, including folded dipole driven elements and quarter-wave transformers, along with the importance of accurate SWR measurements and minimizing coax loss. Demonstrates how to achieve a **1:1 SWR** by carefully trimming elements and adjusting radial angles on groundplane antennas. It provides insights into selecting appropriate coax and connectors, highlighting the benefits of Belden 9913 for low loss and the proper installation of _N-connectors_. The article also addresses RFI mitigation from computer birdies and presents a design for a silent triac antenna control circuit, offering practical solutions for common satellite station challenges.

Javascript for calculating the lengths of tubing to be used for the construction of a Super J-Pole in a collinear design

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.

An on-line javascript calculator and quite a few pictures to show how to make a helix antenna.

Orbitron, a cardware application, provides robust satellite tracking capabilities for radio amateurs and visual observers alike. It leverages NORAD SGP4/SDP4 prediction models to accurately display satellite positions in real-time or simulation, accommodating up to 20,000 objects loaded from _TLE files_. The software includes an advanced search engine for satellite passes and _Iridium flares_, offering printable results for planning observations or QSO attempts. Sebastian Stoff's creation supports various visualization options, including a 'Nightlife' dark color scheme for nocturnal use, and integrates a database of cities and satellite frequencies. Users can synchronize their PC clock via NTP and update TLE data over HTTP, with ZIP support. The application also features rotor and radio control capabilities, either built-in or through user-defined drivers, which is particularly useful for automating antenna pointing during satellite passes. Its interface is designed for ease of use, making satellite tracking accessible even for beginners. First released in 2005, Orbitron 3.71 runs on Windows 9x/Me/2k/XP/2k3/Vista and can operate on Linux via _Wine emulation_, requiring minimal system resources. The software's precision relies on periodic TLE updates, especially for low-Earth orbit objects, to account for orbital decay and maneuvers by satellites like the ISS or Soyuz.

This article describes how to make a quadrifilar helix (QFH) antenna easily, from inexpensive materials: uPVC plumbing pipe and RG-58U co-axial cable. A low-cost, easy-to-build Quadrifilar Helix (QFH) antenna for weather satellite reception using uPVC plumbing pipe and RG-58U coaxial cable. Unlike traditional designs requiring copper pipe and plumbing skills, this approach enables construction with basic tools and minimal technical expertise. The antenna's shorter, wider proportions favor higher elevation angles, reducing interference from horizon-level pager transmitters. Electrical connections are simplified at the antenna's apex, with the coaxial cable forming the radiating elements. Testing demonstrated consistent signal strength throughout satellite passes, proving effective weather satellite reception is achievable without precision engineering to sub-millimeter tolerances.

Presents detailed plans and construction notes for a compact 3-element Yagi antenna specifically designed for the 50 MHz band, authored by Ken Willis, _G8VR_. The article, originally published in _Practical Wireless_ in 1989 and updated in 1999, outlines the design philosophy behind a small, gain-oriented antenna suitable for restricted QTHs. It covers element dimensions, boom length, and a unique coaxial _gamma match_ system, emphasizing a "plumber's delight" construction approach using readily available hardware. The resource details the author's operational experience, achieving _DXCC_ on 50 MHz with over 110 countries worked using this antenna. It also incorporates insights from computer simulation studies by _G3SEK_ and _W1XP_ using _MININEC_, which suggested minor adjustments to element lengths and spacing for improved front-to-back ratio, increasing it from 14dB to 31dB. The author compares theoretical performance with practical results, noting that while larger arrays might offer a few dB more gain, this compact design provides excellent performance for F2 propagation and general 6-meter DXing.

Examines the operational differences between **quad** and **Yagi** antenna designs, focusing on their respective performance characteristics for amateur radio applications. The document highlights key metrics such as forward gain, front-to-back ratio, and bandwidth, which are crucial for effective DXing and contesting. It discusses how element configuration, boom length, and material choices impact the efficiency and radiation patterns of each antenna type across various HF bands. Practical considerations for antenna builders are addressed, including structural integrity, wind loading, and overall weight, particularly when using fiberglass spreaders for quads. The resource also covers precipitation static reduction in quads due to their closed-loop design and their ability to operate efficiently at lower elevations compared to Yagis. It provides insights into dual-polarization feed systems for quads, offering independent vertical and horizontal feed points for enhanced operational flexibility.

A self-supporting vertical antenna design for stationary-mobile HF-VHF operation is presented, emphasizing ease of construction with common materials like a fiberglass fishing rod and PVC pipe. The design focuses on creating a set of no-tuner monoband radiators for bands such as **2m**, **6m**, 10m, and 12m, with an overall radiator support length of 3.3m. The construction process details the assembly of the antenna base using a magnetic mount, PL-259 connector, and PVC pipe sections, which then supports the telescopic fishing rod. Radiator extensions are cut to achieve quarter-wave resonance on specific bands, with detailed instructions for 6m (50-51 MHz), 10m (28.5 MHz), and 12m (24.9 MHz). For lower HF bands like 15m, 17m, and 20m, the design incorporates base-loading coils, with specific turn counts provided (e.g., 21 turns for 20m). The project also suggests using an _antenna analyzer_ for precise tuning of extensions and coils, moving beyond theoretical values to achieve optimal performance. The author, _IK1ZYW_, notes that for 80m and 160m, the antenna becomes less efficient as a vertical, suggesting alternative configurations like an inverted-V dipole or asymmetrical inverted-L.

A 1.5-meter telescopic whip antenna project for the Yaesu FT-817 QRP transceiver is presented, offering a cost-effective alternative to commercial portable antennas like the Whip Miracle. The design incorporates a **toroidal matching unit** with a rotary switch for band selection and a toggle switch for fine-tuning the coil taps. This setup allows operators to achieve a low **Standing Wave Ratio (SWR)** across various HF bands, despite the inherent limitations of a physically short radiator on lower frequencies. The construction details include photographs of the completed unit, showcasing the compact enclosure and the integration with the FT-817. A simple schematic illustrates the coil tapping arrangement and the switching mechanism, guiding hams through the assembly process. The project emphasizes practical, portable operation for **QRP** enthusiasts, acknowledging that while performance on bands like 80m or 40m will be modest, it can still facilitate contacts under favorable conditions with skilled operation.

Discone antenna deisgn program by K5DKZ

For operators seeking to improve their 6-meter mobile operations, W3DHJ presents his **Jones version** of the lawn chair 6M halo antenna, a horizontally polarized design suitable for vehicular use. The project details the thought process, material selection, and construction techniques, including the **gamma match** for impedance transformation. W3DHJ recounts his journey from using a suboptimal 2-meter whip on 6 meters to designing a dedicated antenna for his new IC-706 MKII, aiming for efficient radiation while mobile. The resource outlines the sequential build process, starting with project beginnings and covering mast fabrication, initial halo construction, gamma match implementation, and final tuning. W3DHJ shares his experiences and even mistakes, providing practical insights for fellow homebrewers. The design is specifically engineered to withstand mobile speeds up to 85 MPH, offering a robust solution for enhancing 6M DXing and local contacts from a vehicle.

Demonstrates the construction of a **remote antenna tuner** utilizing a standard radio-controlled (RC) servo mechanism to adjust a variable capacitor. The design focuses on enabling remote tuning for narrow-bandwidth antennas, specifically mentioning frame and packing crate antennas, from within the shack. It covers the mechanical arrangement for integrating the servo with a capacitor and provides a circuit diagram for a control unit that generates the necessary 0.5mS to 1.5mS pulse-width modulation (PWM) signals to drive the servo's 180-degree rotation. This setup was successfully tested with up to 20 watts RF power without arcing or adverse effects on the servo, though tuning was performed at 1 watt for VSWR readings. The resource highlights the use of inexpensive, readily available components, such as Futaba servos, and details critical considerations like power supply decoupling with a 47uF capacitor to prevent unintended servo movement upon power-off. The system provides a practical solution for optimizing antenna performance for specific frequencies without manual adjustment at the antenna itself.

The dipole antenna is an easily designed and made antenna usually used on HF, although can be (and sometimes is) made for VHF and UHF antennas, and in varying forms is also used as part of different designs of antennas i.e. as the driven element for directional antennas.

A new perspective on the analysis and design of this popular antenna element. By Karl-Otto Muller, DG1MFT

Antenna Scatterers Analysis Program, is a Free general purpose antenna analysis software program for numerical electromagnetic antenna design, modeling and analysis. Source code and windows executables are available to download.

An easy to build antenna switch for long wire antennas, expecially designed for sloper antennas

For amateur radio operators utilizing _APRS_ or requiring an external antenna for their GPS receiver, this resource details the construction of a compact, circularly polarized mobile antenna. The design is based on a classic turnstile configuration, employing two dipoles rotated 90° from each other and spaced a quarter-wavelength above a ground plane. A parallel-plate transmission line, fabricated from printed circuit board material, serves as both the connection method and mounting post for the dipoles, simplifying the feed network for circular polarization at 1.57542 GHz. The article outlines the fabrication process, starting with a 4-inch diameter hobby tin or brass base plate and #14 solid copper wire elements. It specifies using _RG-58/U_ or similar 50-ohm coax, with an 8-foot maximum length to minimize loss at the GPS frequency. The parallel-plate transmission line is constructed from two 2-inch lengths of single-sided _FR-4_ or G10 PCB material, 0.062-inch thick, with a specific 45° microwave turn cut on the active side. Final assembly involves an 8-ounce cream cheese container as a radome, and the article discusses the self-phased quadrature feed method to achieve circular polarization without a coaxial phasing line, resulting in an omnidirectional pattern suitable for GPS satellite reception.

3 elements VHF Yagi homebrew antenna designed with YAGIMAX 3. Maximum forward GAIN is about 8,17 DBi. This antenna offering an effective radiation power 4 times greater of the transceiver output by SV1BSX

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 Flower Pot Antenna project details a portable dual-band antenna primarily operating on 10 meters, with secondary resonance near the 30-meter band. Construction involves winding RG58 coaxial cable uniformly around a large plastic flower pot, approximately 70cm high with a 60cm top diameter. The design eliminates the need for radials, contributing to its compact and lightweight nature. Key construction steps include soldering the inner conductor to the shield at one end of the wound cable and connecting the wound cable's shield to the rig cable's inner conductor at the base. An LC network, comprising a variable capacitor (0-200pF) and an inductor (10 coils, 5cm diameter, 2mm wire), is inserted between the wound cable's inner conductor and the rig cable's shield. Tuning is performed with an antenna analyzer, adjusting cable length and the variable capacitor for optimal impedance on 10 meters. The antenna performs effectively when installed horizontally.

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

Constructing a **reduced-size coaxial Moxon rectangle** antenna for the 17-meter band is detailed, presenting a method to achieve a compact directional antenna. The resource outlines the use of RG-58/U coaxial cable for elements, enabling a substantial reduction in physical dimensions compared to traditional wire or tubing Moxon designs. It provides specific instructions for tuning coaxial elements using an **MFJ-259B antenna analyzer**, including a formula to calculate trimming lengths based on measured resonance and desired frequency. The article explains how to prepare the coaxial cable for both driven and reflector elements, specifying connections for testing and final assembly. Performance data from an MFJ-259B shows SWR readings between 1.0 and 1.2 across 18.068 MHz to 18.168 MHz, with R values from 51 to 59 ohms and X values of 0 or 6 ohms. The antenna's power handling is approximately 500 watts continuous, limited by the RG-58/U coax. Comparative receive testing against an All-Band Sterba Curtain at 50 feet indicated a 2 S-unit reduction for the coaxial Moxon at 9 feet, suggesting optimal performance at a height of 34-40 feet for a 15-18 degree take-off angle. The design achieves an electrical quarter wavelength with over 30 percent size reduction.

Build your own antenna for the 23cm band ( 1250Mhz - 1280Mc ) using some aluminium and this simple design.

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

Building a directional antenna for limited space, M0MRR shares his experience constructing a 10-meter Moxon rectangle. Initially using fiberglass fishing poles and a plastic breadboard, he achieved a 1:1.2 SWR across the band with 50 watts, making contacts as far as PY2TO from the UK. The design incorporates 10-amp power cable for elements and RG58 coax with crocodile clips for feeding, demonstrating a cost-effective approach. His field observations confirm the directional properties, noting European signals fading when facing Stateside, and receiving better reports from stations in the antenna's favored direction. While not formally measured, the front-to-back ratio appears effective. The initial build was somewhat flimsy, intended for temporary deployment, but proved effective for DX. Later, M0MRR constructed a more robust 10-meter Moxon using tubular aluminum pipe, indicating an evolution in his design approach for durability. The project highlights practical antenna building for small backyards, emphasizing the benefits of a directional antenna even with modest power.

Two Wire Beverage by Jeff Parke, describes a two-wire Beverage antenna design for improved reception with switchable direction (forward/backward) and lower noise level. It includes details on building the antenna, matching transformers, and a control box for selecting direction and connecting to the receiver.

Build the PAC-12 Antenna a multi-band portable vertical designed by KA5DVS, here's an award-winning, easy-to-homebrew, multi-band portable vertical antenna designed by long-time antenna aficionado James Bennett, KA5DVS. He's documented the design and construction plans for a portable antenna

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

The 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.

The _Morgain_ antenna for 40/80 meters is a straightforward and cost-effective wire antenna design, requiring careful tuning for optimal performance across two bands with low SWR. Construction involves creating 12 cm PVC spacers with three holes for wire insertion, along with larger terminals for anchoring and connector housing, which should be sealed with silicone. The provided measurements detail the specific lengths for the antenna elements, crucial for achieving resonance on both 40m and 80m bands. Tuning the Morgain antenna necessitates fabricating four wire segments with pins to temporarily connect and adjust the bridging points symmetrically for both 40m and 80m. This iterative process, though time-consuming, ensures the antenna functions effectively for decades once the precise connection points are soldered and protected. The design emphasizes ease of construction and long-term stability, making it a practical solution for hams seeking a dual-band wire antenna.

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.

The 20-meter homebrew **Moxon antenna** project by 9Y4DD, Dave, details the construction of a 14 MHz directional antenna using readily available and repurposed materials. Initial SWR readings at 6 feet were 1.2 at 14.000 MHz, 1.4 at 14.350 MHz, and 1.1 at 14.175 MHz, with a subsequent increase of 0.1 on all frequencies when raised to 15 feet. The design adheres to specifications provided by L.B. Cebik (W4RNL). Key components include a discarded domestic water pump pressure tank as the center mounting bracket, 1/2-inch PVC conduit for spreaders, and 1/2-inch CPVC hot water pipe inserts to enhance rigidity. The total weight of the antenna is 12.625 pounds, with a material cost of U.S.$36.63. The spreaders are 165 inches from the center, utilizing 2.5mm sq. stranded copper wire for the elements. Dave's design incorporates hexagonal 'spider webs' of waxed twine to stabilize the flexible PVC spreaders, addressing initial issues with wind-induced movement. Separators cut from 3/16-inch Plexiglas maintain an 8.6-inch element spacing. The antenna demonstrated effective DX contacts with Europe from Trinidad, showing improved noise reduction compared to an inverted V.

Constructing and designing full size, single band stacked yagi antenna arrays

Plans, photos, electrical and mechanical design for this HF Log periodic antenna.

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

M1PAF's 20 Meter Vertical Moxon antenna design, based on Pete Mills' EZNEC model, utilizes a push-up GRP mast and Tufnol plate for mounting cross arms, minimizing metallic elements within the beam. Hydraulic pipe clamps, also plastic, secure the tube clamps, with only two bolts and a plate being metallic. Dog bone insulators with Kevlar line and snap links facilitate quick wire element attachment, ensuring tension in all dimensions. The antenna's support structure includes Tufnol guying rings for Kevlar guys, providing stability against high winds. The cross arms are constructed from three 1-meter sections, allowing for convenient packing. This portable setup was successfully deployed adjacent to the ocean, enabling over 4500 QSOs in six days with 100W, achieving easy contacts into Japan and Asia. The design emphasizes ease of erection by a single operator and robust performance in challenging environments. Components for the cross arms were sourced from Spiderbeam. Further information is available via M1PAF's QRZ.com details.

Article designed to answer basic questions about antennas

This page describes the design and construction materials W8WWV used to build a coaxial cable trap. A coaxial cable trap is a parallel resonant circuit that is usually inserted in an antenna element to enable multiband operation.