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A web site dedicated to the K3LR contest station, a Multi Multi Station with 9 towers located in Western Pennsylvania. It provides information about the station components, antenna construction company, radio equipment used, and upcoming events like the Top Band Dinner at Dayton. The site also includes links to related resources like Contest University, Dayton Contest Dinner, and World Wide Radio Operators Foundation. The intended audience is amateur radio operators interested in contesting and DXing. The content is focused on promoting the K3LR station and sharing news and updates related to its activities.

This PDF document, authored by KT4QW in October 2004, details the construction and modeling of a dual-band, horizontally polarized hanging rectangular loop antenna for **10 and 17 meters**. The design, adapted from *The ARRL Handbook*, utilizes _NEC4WIN95_ software for scaling and optimization, targeting a 50 ohm feedpoint impedance. The resource includes a bill of materials, step-by-step construction instructions, and a discussion of the antenna's radiation characteristics. It presents NEC-generated elevation and azimuth patterns, comparing the loop's performance to a half-wave horizontal dipole at the same height and frequency. The 17-meter element is centered at 18.140 MHz for low SWR across the phone band, while the 10-meter element is centered at 28.500 MHz. Construction involves 14-gauge stranded copper wire and Schedule 40 PVC spreaders, with the total wire length calculated by the formula: Length in feet = 1005/MHz. The feedpoint impedance can be adjusted by modifying the rectangular aspect ratio. The document specifies hoisting the antenna to at least a half-wave above ground for testing. It notes that a balun was tested and found to have no measurable effect on SWR or radiation characteristics. A 2-meter scale model is presented to illustrate the physical design, and a "rotator" string is incorporated for directional adjustment up to 90 degrees.

Designing a compact directional antenna for the 70cm band involves balancing gain, front-to-back ratio, and physical size. This resource details the construction of a 2-element Moxon rectangle antenna for 432 MHz, outlining the specific dimensions for the driven element and reflector, and discussing the advantages of its folded dipole configuration. The article provides insights into the historical context of 70cm operations and the author's personal experiences with early 432 MHz transceivers and antenna setups, such as a Jaybeam 48-element TV antenna. It also touches upon the practical aspects of building and deploying such an antenna for local and weak-signal work. The Moxon antenna design is compared to a 3-element Yagi, noting its superior front-to-back ratio and broader bandwidth for a given boom length, making it suitable for portable operations or restricted spaces. The construction uses readily available materials like copper wire and PVC tubing, emphasizing simplicity and ease of replication. Performance characteristics, including a reported gain of approximately 5.5 dBi and a front-to-back ratio of 20 dB, are discussed in the context of its compact footprint. The resource includes a visual representation of the antenna's dimensions and construction, aiding in practical implementation.

The provided resource offers a downloadable ZIP archive, "6 meter moxon.zip," containing comprehensive design files for a **6-meter Moxon antenna**. Specifically, it includes antenna models in EZNEC format, allowing radio amateurs to simulate and analyze the antenna's performance characteristics. The archive also features detailed drawings, photographic documentation of the construction, and various plots illustrating the antenna's radiation patterns and impedance matching. Authored by Allen Baker, KG4JJH, the content focuses on a horizontally polarized Moxon antenna optimized for 50.5 MHz. The EZNEC files, such as "Moxon 6m 50.5 MHz H-POL.EZc," provide precise geometric and electrical parameters for replication or modification. The collection of files, totaling approximately 10 MB, serves as a practical guide for hams interested in building or understanding the design principles of a compact, directional 6-meter antenna, presenting both theoretical models and visual construction aids.

GNU Radio is a collection of software that when combined with minimal hardware, allows the construction of radios where the actual waveforms transmitted and received are defined by software

Construction of a 4 legged 20 foot Tower at vk5sw

This technical note explores the application of **Moxon rectangle** antennas for WARC bands, specifically 17 and 12 meters, as compact directional alternatives to standard Yagis. It details three design approaches: a dual-band Moxon using open-sleeve coupling, a Moxon-Yagi combination, and a simplified 1.5 Moxon rectangle. The document provides specific dimensions in feet for aluminum tubing elements (0.75" and 0.5" diameter) for each configuration, along with projected free-space gain, front-to-back ratio, and feedpoint impedance (R+/-jX Ohms) across the respective band segments. Performance tables illustrate gain (dBi), front-to-back ratio (dB), and 50-Ohm VSWR for each design. The dual-band Moxon, despite its compact 7-foot boom, is not recommended due to extreme sensitivity to construction variations, leading to rapidly changing performance characteristics. The Moxon-Yagi combination, featuring a 17-meter Moxon and a 12-meter director-driver Yagi, is presented as a more practical and adjustable solution, offering stable performance with a 10-foot boom. NEC model descriptions are included for simulation in programs like EZNEC, NEC-Win Plus, AO, or NEC4WIN.

Antenna Warehouse provides a range of certified quality wire products for amateur radio and general communication applications. Their inventory includes Francis antennas, known for their robust construction, alongside the versatile Select-A-Tenna series. The company also stocks Solarcon 10/11 meter base antennas, catering to specific band requirements for 27-28 MHz operations, and various Wilson antenna models. Beyond product sales, Antenna Warehouse offers services such as antenna tower installation, repair, and removal. These services support the complete lifecycle of antenna systems, from initial setup to maintenance and decommissioning. The product selection emphasizes components for both fixed station and mobile installations.

In 1999, W5GVE presented a detailed construction article for a 2-meter _DDRR_ antenna, specifically designed for mobile operation. This unique antenna, a Directional Discontinuity Ring Radiator, offers a compact footprint, making it suitable for vehicular mounting where traditional quarter-wave verticals might be impractical. The design emphasizes ease of homebrewing, utilizing readily available materials and basic workshop tools, allowing radio amateurs to build an effective mobile antenna for the 144 MHz band. The article provides insights into the antenna's performance characteristics, noting its low profile and potential for reduced wind loading compared to taller mobile whips. W5GVE's experience with the DDRR design suggests it can provide reliable communications on the 2-meter band, even in challenging mobile environments. The construction details include specific dimensions and assembly steps, guiding the builder through the process of creating a functional antenna. This project offers a practical alternative for hams seeking a discreet yet effective 2-meter mobile antenna, potentially achieving **3 dB** gain over a standard mobile whip.

AA5TB home made CW paddles, pictures and construction details

The 6 Band Inverted L Antenna MK3 is a versatile multiband antenna designed for amateur radio operators. This antenna covers 160m, 80m, 40m, 20m, 15m, and 10m bands, making it suitable for a wide range of HF communications. The design is based on a W3DZZ configuration, incorporating traps for optimal performance. The MK3 version features a sturdy 5/8th CB mast, replacing the original timber mast, which enhances durability against harsh weather conditions. The antenna's construction allows for effective operation, particularly on the 40m band, where it has been successfully used to contact distant locations including ZL, VK, and Antarctica. Constructing this antenna requires careful attention to detail, especially regarding the radials and grounding. The traps resonate at specific frequencies, and additional resources are available for building coaxial traps. The antenna is designed to work efficiently without an ATU on the lower bands, while higher bands may require tuning. This project is ideal for both beginner and intermediate operators looking to enhance their station with a reliable multiband antenna.

An experimental antenna, similar to the _TAK spiral antenna_, was evaluated for SWR response over the 7.0 to 7.3 MHz frequency range. The analysis presents specific results: beam length significantly affects SWR, with increased distance between spirals raising the resonant frequency; the combined length of antenna and hookup wire lowers the resonant frequency as it increases; and spiral diameter impacts bandwidth, with larger diameters yielding greater bandwidth. The design addresses the fixed beam length limitation of the commercial TAK antenna by introducing an adjustable version constructed primarily from PVC electrical conduit and water pipe, using 14-gauge aluminum wire. The resource includes a detailed mechanical design, construction steps, and a parts list. It also features a spiral antenna spreadsheet model for calculating design parameters like start point, pitch, safe edge, spoke length, and arm length, which aids in determining wire length and kerf cutting tables. Model verification involved constructing an antenna to specific parameters, with SWR tests conducted using an _MFJ Model 269_ antenna analyzer at 13 feet above ground with 60 feet of RG8 mini coax. Measurements showed that adjusting beam length from 27 to 37 inches shifted the resonant frequency by approximately 0.18 MHz. Further data compares 32-inch versus 48-inch diameter spirals, demonstrating increased bandwidth for the larger diameter. The model accurately predicted revolutions for given antenna lengths, pitch, and starting distances. The final design achieved a resonant frequency of 7.17 MHz, favoring the voice portion of the 40-meter band after adjustments.

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.

W1ZY's 40-meter **Moxon** antenna project details nine months of experimentation, culminating in a reversible array built from No. 12 insulated wire. The design incorporates two RF current baluns and a unique two-wire element construction, where each element consists of two parallel wires spaced 3 inches apart. The resource provides specific dimensions for the first prototype, including A=50.98', B=7.87', C=1.25', D=9.3', and E=18.42', optimized for 7.050 MHz CW operation. It thoroughly explains the construction of custom two-wire insulators from Plexiglas semi-rods and the critical pre-tensioning process required to maintain wire separation and array integrity. The author, Bill, emphasizes the antenna's exceptional receive performance, noting a 30-35 dB front-to-back ratio, which allows for significant signal rejection from the rear. While the Moxon offers 5-6 dB gain on transmit, its primary advantage lies in its ability to radically reduce rear-facing signals on receive, a characteristic Bill believes is often overlooked in transmit-focused comparisons. The guide details a flexible tuning method using removable tail-end jumpers, enabling adjustments to both tail-end and parallel dimensions without re-soldering the feed point, a technique refined over three prototypes.

The Regen Shortwave Receiver using Manhattan-style ugly construction techniques.

Constructing a compact UHF Moxon antenna for portable radio or TV applications demands a small, easily transportable aerial. This project focuses on a straightforward build method rather than a specific frequency design, leveraging _MoxGen_ software by AC6LA to derive precise dimensions. The author's approach utilizes an epoxy printed circuit board as the support, with traces drawn by a special felt-tip pen for soldering the antenna elements after an etching bath. For high-frequency work, particularly in the GHz range, the choice of insulating material is critical; the article emphasizes the necessity of quality UHF or SHF-grade insulation. A standard SMA connector is integrated, with one element making electrical contact via the nut and the other soldered to the central pin. This ensures a robust feedpoint for the coaxial cable. The coaxial cable, fitted with its connector, is threaded through a 12mm PVC tube that functions as a mini-mast. This tube also defines the antenna's forward direction, which should be aimed at the target signal. A sanitary clamp at the base of the tube secures it to a photographic tripod via its 7mm thread, providing a stable and portable mounting solution.

For radio amateurs seeking compact, directional antenna solutions, the Moxon Rectangle offers an attractive alternative to traditional two-element Yagis. This resource compiles several articles by L. B. Cebik, W4RNL, exploring the **Moxon Rectangle** design, which provides gain comparable to a full-size two-element array but with a significantly improved **front-to-back ratio** and a direct 50-Ohm feedpoint match. The collection covers both wire arrays, particularly for lower HF bands, and rotatable aluminum beam constructions, addressing various aspects of this popular antenna configuration. The articles delve into specific band applications, including designs for 10 meters, 40 meters, and 2 meters, alongside discussions on multi-banding techniques and pattern characteristics. Comparisons are drawn between the Moxon and other antenna types, such as VK2ABQ Squares, highlighting the Moxon's advantages in terms of size and performance. Practical construction notes are provided for both wire and aluminum versions, offering insights into building these antennas for different operating environments.

The article "Exploring the World of 10 Meter Beacons" by Ken Reitz, KS4ZR, provides an in-depth look at 10-meter beacon operations, focusing on their utility for propagation analysis. It details FCC Rules part 97.203 governing beacon stations, including license requirements, power limits (under 100 watts), and the specified band segment of 28.200-28.300 MHz for U.S. operations. The content highlights the diversity in beacon construction, from converted CB radios to home-brew QRP transmitters, and discusses the robust operating conditions these 24/7 stations endure. The resource presents several case studies of active 10-meter beacon operators like Ron Anderson KA0PSE/B, Domenic Bianco KC9GNK/B, and Bill Hays WJ5O/B, detailing their equipment, antenna setups, and typical signal report volumes. It also introduces the NCDXF/IARU International Beacon Project, which features 18 synchronized beacons worldwide transmitting on 28.200 MHz at varying power levels (100W, 10W, 1W, 100mW) to facilitate propagation testing. The article also covers the PropNet Project utilizing PSK31 on 28.131 MHz and the 250 Synchronized Propagation Beacon Project on 28.250 MHz. Practical advice for monitoring includes using the RST reporting method, understanding the impact of the solar cycle on 10-meter propagation, and tips for setting up a personal beacon, such as frequency selection and power output considerations. The IY4M Guglielmo Marconi Memorial Beacon Robot on 28.195 MHz is also mentioned for its automatic QSO mode. The article concludes with a list of other resources for 10-meter beacon information.

Video construction of a multiband HF trapped dipole antenna based on a variation of the classic W3DZZ design

Article on the HF dual band antenna with construction details and how to add 160 meters to the HF2V

A quarter-wave vertical antenna design for HF operation offers a practical solution for radio amateurs seeking a compact and efficient multi-band radiator. This project details the construction of a 5-band HF vertical, drawing inspiration from established commercial products such as the _DX COMMANDER_ and the MV6. The design emphasizes ease of assembly and disassembly, making it suitable for portable operations or installations with limited space. The article provides insights into various construction methods and offers practical tips for building a robust yet lightweight antenna. It highlights the benefits of a vertical configuration for DX contacts, particularly on the lower HF bands, and discusses real-world performance observations. The antenna is designed to cover multiple HF bands, providing versatility for various operating scenarios. Operators can achieve significant DX results with this type of antenna, often comparable to more complex arrays, especially when deployed with an effective ground system. The project aims to empower hams to build a capable antenna without significant financial outlay.

The 10-meter EH Antenna document details the construction and performance of a specific EH antenna design for the 10-meter band. It describes the integration of an L+L balanced matching network, a key component for impedance transformation, and highlights the addition of a tuned coaxial trap. This trap, consisting of 8 turns of RG58 coax wound around PVC tube and resonated at 29 MHz with a 10 pF capacitor, effectively inhibits common-mode current on the feeder, stabilizing antenna tuning. The resource presents a circuit diagram in Figure 1 and assembly details in Figure 2, illustrating the use of PVC plumbing tube as host material for dipole cylinders made from recycled aluminum tubing. It also explains the fabrication of capacitor stators and slider sections from thin aluminum tubing. The author, Lloyd Butler VK5BR, discusses initial challenges with feeder interaction and how the tuned trap resolved these issues, leading to stable tuning. Limited backyard tests indicate that the antenna, with the trap fitted close to the input connector, might exhibit similar field strength for both low and high angle transmission, suggesting a potential skewing of the signal. The document references previous articles by VK5BR in "Amateur Radio" for further operational details of the matching network and trap functionality.

The ARRL page, titled "The HF Mobile Antenna," serves as a curated index to various _QST_ articles focusing on constructing mobile HF antennas. It presents several projects for the mechanically inclined amateur, suggesting that homebrewed antennas can achieve efficiency comparable to commercial versions. For instance, one entry details a **five-band** antenna for RVs, utilizing a fold-over Hustler 4BTV, while another describes a "Bug Catcher" design for 80 through 10 meters. Further projects include a budget-friendly $20 HF mobile antenna made from PVC and wire, covering 20 through 6 meters, and the "Alpha Special," a multiband horizontal antenna originally for 1960s station wagons, now suggested for mini-vans. The resource also addresses antenna mounting solutions specifically for travel trailers and campers, providing practical insights for those operating from recreational vehicles. Rounding out the collection are the "Connecticut Longhorn," a 75-meter horizontal whip with remote tuning, and its redesign, the "Connecticut Shorthorn," adapted for smaller vehicles post-1970s. This compilation offers a historical perspective on mobile antenna innovation and practical construction guides for various HF bands and vehicle types.

The page describes the construction of a simple omnidirectional, vertically-polarised dipole antenna for two metres using coaxial cable. It can be used indoors or outdoors, with no extravagant gain claims. The project is low-cost and can be completed in about 20 minutes.

Constructing a compact, two-band magnetic loop antenna for HF operation, especially from constrained locations like a balcony, presents unique challenges. OK1FOU's design, inspired by DJ3RW's 50 MHz loop, addresses these by employing an unusual side-fed configuration and placing the symmetric, two-section variable tuning capacitor at the bottom of the loop, directly connected to the coax shield. The article provides specific material recommendations, including two 1-meter wooden pales and about 3 meters of thick loudspeaker cable, noting the high current (60A at 100W) in the loop. Construction steps detail forming two turns with a 5 cm gap, using a GDO to pre-tune the open loop to a frequency slightly above the desired highest band, and then integrating the tuning and coupling capacitors. For 10/14 MHz, an open loop resonance of 16-17 MHz is suggested. Practical experience with the 10 MHz band from a third-floor balcony in Prague (JO70GC) shows a 1:1 SWR across most of the band without an external ATU. While DX traffic was modest due to the urban environment, QSO examples with RA6WF, LA6GIA, G0NXA, and LZ1QK on 10 MHz are provided, demonstrating its operational capability.

Demonstrates a practical modification to convert a standard G5RV antenna into a _160-RV_ for effective operation on the 160-meter band. This project addresses the challenge of achieving Top Band resonance with a common multi-band wire antenna, providing a solution for hams with limited space or resources for dedicated 160m antennas. The design utilizes a specific length of 450-ohm ladder line and a 1:1 current balun, acting as a matching section to bring the G5RV's impedance into a usable range for 1.8 MHz. The document includes a parts list, detailed construction steps, and tuning instructions, emphasizing the importance of precise measurements for the ladder line and coaxial cable sections. It also outlines the expected SWR characteristics and power handling capabilities, making it suitable for QRO operation up to 1.5 kW. The _AD1B_ design offers a straightforward approach for extending the utility of an existing G5RV.

Ham Radio Tower Project at N0HR. Includes site plan, escavation, tower construction, HF antennas, grounding and lightning protection, coax and more.

Presents the design and construction of the OK2FJ Bigatas, a portable, automatically tuned vertical antenna covering 80 through 10 meters. It details two distinct control systems: one utilizing BCD band data from Yaesu FT-857/897 transceivers, and another employing voltage level sensing for the Yaesu FT-817. The resource provides specific instructions for building the antenna's radiating element, loading coil with switchable taps, and the control circuitry, emphasizing the use of readily available components. The article outlines the physical construction of the antenna, including the use of duralumin tubes for the radiator and a PVC tube for the coil form. It specifies coil winding details, tap points, and the integration of radial wires for ground plane operation. The control electronics section provides schematics and component lists for both the BCD decoder (using a 74LS42 IC) and the voltage comparator (using an _LM3914_ bargraph driver), enabling rapid, automatic band switching without the minute-long tuning delays common in other systems. Crucially, the antenna achieves rapid band changes, with typical SWR values centered on common operating segments, such as **3.7 MHz** for 80m SSB. It also discusses modifications for CW operation on 80m and the trade-offs between antenna efficiency and full-range automatic tuning on higher HF bands, where manual adjustment of radiator length is suggested for optimal performance on 15m, 12m, and 10m. The resource includes construction photos and a discussion of cable requirements for reliable operation.

Demonstrates the construction of a base-loaded quarter-wave vertical whip antenna, suitable for both mobile and portable HF operations. This design utilizes a vehicle body as a ground plane for mobile use or a counterpoise for field deployment. The article details the selection of materials, such as a _glass fibre tubing_ former and 24 s.w.g enamelled copper wire for the loading coil, with specific turn counts suggested for 20m (around **30 turns**) and 40m (around **50-60 turns**). It outlines a practical tuning method using an SWR bridge and even an audible signal approach, emphasizing careful adjustment of coil turn spacing or whip length to achieve optimal SWR. The resource also mentions the use of an antenna analyzer for more precise tuning, contrasting it with the SWR method.

Also known as Magnetic Loop Antennas, by AA5TB. Excellent article on construction tips and tecniques of a Small Loop antenna

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.

Communication Concepts, Inc. specializes in providing RF components for both amateur radio operators building their own gear and professionals prototyping circuit designs. The inventory includes a range of products such as HF and VHF amplifiers, splitter combiners, and various filters, catering to diverse applications from QRP to high-power systems. The site details specific components like _Freescale_ and _Motorola_ RF transistors, along with custom semi-rigid coaxial cable options. The offerings extend to parts for ATV, packet radio, and general electronic components, emphasizing quality and service since 1979. Customers can find items like low-pass filters for RFI/TVI mitigation and specialized transformers for RF power systems, covering frequencies from 2-30 MHz Type "H" to 1-80 MHz high-power applications. The resource highlights its role as a supplier for those constructing custom radio equipment, offering components that facilitate projects from basic radio kits to advanced amplifier designs, with a focus on enabling self-construction and cost-effective prototyping.

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.

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.

Article about magnetic loops, construction notes and diagrams

Hints about Jpole Yagi and Quad antennas

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.

Online calculator and construction instructions

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.

Build a spiderbeam from scratch for 20-17-15-12-10 meters band

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.

Restoring vintage amateur radio gear often presents challenges with accurate dial calibration due to the non-linear characteristics of analog tuning capacitors. This resource details the construction of a 100 kHz crystal calibrator, a crucial tool for precisely setting the frequency of older rigs lacking digital readouts. The design cleverly circumvents the scarcity and cost of 100 kHz crystals by utilizing a readily available 8 MHz microprocessor crystal, such as a _HC49U_ type, in conjunction with common _CMOS ICs_ like the 74HCT00 quad NAND gate and 74HCT393 dual 4-bit binary ripple counter. The circuit employs a two-stage frequency division process: the 8 MHz crystal oscillator output is first divided by 16 to yield 500 kHz, then further divided by 5 to achieve the desired 100 kHz output. A 5.1-volt Zener diode, _1N4733A_, regulates the power supply for the HCT series logic. The article also provides a modification to produce a 50 kHz calibrator by altering the counter reset logic. Installation involves feeding the output to the receiver front end, ensuring it's post-TR relay to prevent RF damage, and incorporating an ON/OFF switch for the 12V supply line.

The design of Ruthroff broadband voltage transformers

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.

Compiling an extensive collection of technical information, the Repeater Builder's website serves as a critical resource for those involved in amateur and commercial repeater systems. It covers a broad spectrum of topics essential for the design, construction, and ongoing maintenance of these vital communication hubs, drawing from years of practical experience in the field. The site provides detailed insights into various aspects of repeater technology, including specific information on VHF and UHF bands, such as 2-meter systems. Users can find data related to repeater logic, control systems, and interfacing with other radio infrastructure, all presented with a focus on practical application. Authored by Kevin Custer, W3KKC, the content reflects a deep understanding of repeater operations and engineering, offering guidance that extends beyond basic setup to advanced troubleshooting and optimization.

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.

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 page about a Magnetic loop antenna project for the 40 meters band, includes nice pictures and history of construction

A self supporting vertical antenna for 80 meters by W9OY include pictures and construction details