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The RXC70/10 is a sensitive 70 MHz to 10-meterband converter using the Philips SA602 mixer IC. It operates with high stability and low noise, converting 70–72 MHz signals to 28–30 MHz for general coverage receivers. The compact, low-power design (15mA) supports various modulations and uses. Its versatility makes it suitable for amateur radio applications with proper tuning and antenna setup.

Operating on the 60m band requires specialized antennas, and the 2 Element HB9CV, also known as the _ZL special_, excels in this domain. With a gain of **7.3 dBi** when phased at a 162-degree shift, it rivals traditional 3-element Yagi antennas, making it a solid option for enhancing 60m operations. The construction process is thoroughly detailed, providing insights into its performance and practical applications. Real-world comparisons demonstrate that the HB9CV antenna outperforms long Beverage antennas by an average of **5.5 dB** in reception, showcasing its effectiveness in various conditions. Insights from Mr. Cebik's analysis further validate its design, confirming its capability to maximize communication on the 60m band.

A guide to constructing a simple quarter-wave ground plane antenna, detailing design principles and providing dimensions for VHF/UHF bands

This page provides information on how to design an Off-Center-Fed Dipole (OCFD) antenna, suitable for amateur HF bands like 80 meters or 40 meters. The antenna design allows for VSWR minima on multiple bands, making it a good choice for multi-band use. Learn how to create an OCFD antenna in either flat-top or inverted-Vee form using a single support. The page also offers tools to generate radiation patterns, VSWR charts, and antenna current diagrams for your specific antenna design, helping hams understand performance factors. Ideal for ham radio operators looking to build their own effective antennas.

YAGio 1.01 is a Windows-based software for designing DL6WU long Yagi antennas on VHF and UHF frequencies. It supports Windows 2000, XP, Vista, 7, and likely 8. Using keyboard commands, users input specifications such as frequency, gain, and element diameters, and YAGio generates the design. You can download latest Yagio version from this page. Results can be saved in YIO, NEC, YAG, MMA, and YC6 formats, or printed directly.

Antenna project for a home made quagi antenna for UHF Bands, 432 MHz. This projects is done using some aluminium bar rods and includes design and pictures of the project

This article explores the role of velocity factor (VF) in calculating stub lengths for VHF/UHF Baluns. It clarifies misconceptions about VF's relevance, distinguishing between coaxial cable interior fields and external stub fields. Practical examples, such as the Pawsey Stub and Coaxial Cable Balun, are analyzed alongside experimental findings. The results reveal that traditional VF adjustments are unnecessary for stubs with external fields but critical for internal coaxial applications. Historical and theoretical insights provide a comprehensive perspective for antenna enthusiasts and designers.

This paper presents an 80 meter wire 3-element beam antenna in an inverted-V configuration, designed for limited-height towers. Using EZNEC modeling, the antenna features a central parasitic reflector and two switchable driven elements at each end, enabling NE/SW coverage without moving parts or networks. Element lengths are optimized for SSB (3.8 MHz) and CW (3.5 MHz) operation, with a 50 Ω feed and rope-supported boom. The design delivers high gain, effective takeoff angles, and excellent reception, confirmed in real-world DX contest operation. Its simplicity, reliability, and ease of construction make it ideal for operators seeking performance without complex matching systems.

The Slim Jim VHF antenna, originally designed by G2BCX, is a folded half-wave dipole fed by a quarter-wave matching section. This version, built from a recycled professional aluminum dipole, demonstrates that various materials—such as copper, brass, or twin-lead—can be used. The article details the antenna’s construction, required materials, and tuning process, emphasizing mechanical stability and ease of assembly. With proper adjustment of the feed point, it provides excellent SWR across the band. Its durability and simplicity make it a practical and efficient VHF antenna solution.

This project outlines a simple, cost-effective 40m band HF dipole antenna design, ideal for beginners. Constructed with insulated copper wire and a 1:1 balun, it offers a 50-ohm impedance, suitable for both 40m and 15m bands due to the harmonic relationship. Calculations account for a K factor, ensuring optimal length and performance. Antenna modeling with 4NEC2 confirms practical access to both bands, though real-world results may vary. Lightweight materials and straightforward assembly make it an accessible and versatile amateur radio solution.

VE1ZAC's analysis details the performance of **MFJ927** and **SGC239** autotuners with portable HF vertical antennas, specifically comparing 31 ft and 43 ft configurations. The resource originated from challenges encountered during a Maritime QSO Party roving operation, necessitating a lightweight and easily deployable antenna system. Target bands for the contest included 80, 40, 20, 15, and 10 meters, with a maximum power handling of 100 W CW. The author utilized a 30-foot carbon fiber push-up pole to support a vertical wire element, noting its 2 lb weight and reliability. EZNEC modeling was employed to predict performance, showing favorable results for a 30-foot vertical with elevated radials, particularly on 40 and 20 meters. Feedpoint impedance measurements, taken with an AIM4170C, are presented for various HF bands, both with and without a 41-foot RG6 stub designed to reduce reactance on 80 and 20 meters. The stub significantly improved matching on these bands, easing the tuner's workload. Operational tests revealed issues with the MFJ927's reliability during contest setup, leading to reliance on the K3's internal tuner. The SGC239, tested post-contest, performed flawlessly. A detailed side-by-side comparison covers mechanical aspects, connection options, power bias, impedance range, board quality, and documentation. Modifications to the MFJ927, including a new aluminum case, white paint for heat reduction, and upgraded impedance-measuring resistors, are also described.

This article describes the design and construction of a 4-meter band vertical sleeved dipole antenna, built to complement a newly acquired Yaesu FTDX10 transceiver. The simple yet effective antenna consists of modified coaxial cable housed in weather-resistant plastic conduit, featuring an integrated 8-turn choke coil. Despite common misidentification as an EFHW antenna, this design is actually a sleeved dipole that provides an excellent 50-ohm match across the band, achieving SWR values between 1:1 and 1.1:1. The project demonstrates an economical approach to entering the relatively quiet 4-meter band.

The LKJ Wednesday Night Special Antenna, designed by John Whiteman K5LKJ, is a compact 50-foot coil-loaded dipole for 80-meter operation, ideal for space-limited hams in residential areas. Using two 1-inch diameter PVC coils with 87 turns of #16 magnet wire each—placed 10 feet from the center—it tunes to 3.910 MHz for local nets like BVARC Rag Chew. Constructed with #14 wire, ceramic insulators, and Mini-8X feedline, it handles 1000W, performs well at low heights for NVIS, and requires a tuner for bandwidth. Collaborative tuning by club members ensured success.

A full-wave delta loop antenna, approximately 141 feet in total wire length for the 40-meter band, offers a low angle of radiation, which is highly advantageous for DX operations. This design, optimized for both 30m and 40m, leverages a specific circumference calculation of 1005/F, ensuring resonance on both bands through a simple switching mechanism. The antenna's configuration enhances long-distance communication, making it a practical choice for hams with limited space. The resource details the construction process, including the use of a _Ceramic Knife Switch_ for band selection and an _RG-11_ matching section to achieve optimal impedance. It outlines the precise loop lengths required for each band, along with tuning secrets to ensure efficient operation. Requiring a minimum height of 12 feet, this antenna can be supported by a single mast or tree limb, making it suitable for suburban installations where stealth or space constraints are a factor.

This paper by Leif Asbrink (SM 5 BSZ) presents a practical approach to designing very high gain Yagi antennas, focusing on the "brute force" optimization method. The method, described in a previous article, ensures convergence independent of initial guesses. The paper provides detailed tables of element lengths and positions for Yagi antennas optimized for 144.1 MHz with a 50-ohm feed point impedance, aiming for minimal losses and high accuracy in comparisons.

This article describes a DIY RF field strength meter project inspired by VK3YE's "The Squeakie" design. The device, built around a 555 timer IC and a 1N4148 diode, converts RF signal strength into audible tones with proportional pitch. The author enhanced the original design by adding volume control, LED indication, and digital readout capabilities using an Arduino Nano and LCD display. The completed project functions as a versatile RF detection tool, suitable for antenna testing and fox hunting, while offering multiple output methods: audio, visual, and digital measurement display.

This resource presents a non-rigorous evaluation of the front-to-back (F/B) ratio of short Beverage antennas, specifically designed for low-band operation on frequencies such as 160, 80, 40, and 30 meters. The author, VE1ZAC, details the methodology used to measure the F/B ratio, which involves using a Millen Grid Dip Oscillator as a portable signal source. Measurements were taken by switching the antenna direction and recording S Meter and preamp readings to derive gain numbers. The document discusses the challenges faced in achieving accurate measurements and the assumptions made during the process, such as the calibration of S Meter units at 6 dB. This evaluation is particularly relevant for amateur radio operators interested in antenna performance on low bands.

Twenty 1-watt carbon film resistors are configured in parallel to construct a 50-ohm **dummy load** for amateur radio applications. The design incorporates a heatsink for thermal dissipation and an **SO-239 connector** for RF input, making it suitable for QRP operations. This budget-friendly project details component selection, soldering techniques, and mounting procedures, achieving a continuous power rating of 10 watts and intermittent handling of up to 100 watts across HF and VHF frequency ranges. The resource provides a step-by-step guide for assembly. This construction offers an economical solution for essential shack tasks such as antenna tuning, transmitter testing, and SWR meter calibration without radiating an RF signal. The utilization of readily available components significantly reduces the overall build cost compared to commercial alternatives, providing radio amateurs with a functional and reliable test accessory. While specific VSWR measurements are not provided, the design prioritizes practical utility for low-power transceiver diagnostics and general RF experimentation.

This web page offers an online antenna designer tool for hams to calculate the dimensions needed to construct a J Pole antenna for any desired frequency. The J Pole antenna is a simplified version of the Slim Jim antenna, radiating and receiving signals in an omni-directional pattern. It does not require a ground plane, making it suitable for indoor mounting. With the ability to be made from common household wiring, this antenna performs well for both receiving and transmitting purposes. The calculator is based on radio waves traveling at the speed of light and provides metrics in both imperial and metric units.

This page offers an online tool to calculate the dimensions for a quarter wave antenna based on a specified frequency. It helps hams design antennas for optimal reception and transmission properties, using 1/4 wavelength elements. The calculator ensures a matching impedance of 50 Ohm without the need for additional components. The page is useful for amateur radio operators looking to build efficient antennas for their radio communication setup.

This project describes a high-performance EME antenna array consisting of two home-designed 9-element Yagis, each about 2.5 wavelengths long, combined into a 25-ohm system and matched to 100 ohms using 9/4λ sections of 50-ohm coax. The array supports rotatable polarity from 0° to 180°, allowing both horizontal and vertical polarization to optimize moonbounce performance under varying conditions. Despite operating for years without a balun—something another designer called “disastrous”—the system has delivered strong results, including copying very weak DX such as VK3KH at about -25 dB with only 120 W (around 2 kW ERP). The builder continues to refine the mechanics, having installed new gear motors and an upgraded follow-up control system in 2011.

Demonstrates the design and modeling of a **160m** vertical antenna, dubbed the "WindoVert," specifically for urban amateur radio operators with limited space. The resource covers the theoretical underpinnings of antenna height and radiation patterns, using EZNEC software to analyze current distribution and 3D radiation patterns for various configurations, including a Marconi-style "T" antenna. It details the integration of existing antenna components, such as a Carolina Windom balun and line isolator, into the new vertical setup, and the practical measurement of feedpoint impedance using an antenna analyzer. The article further explores the challenges of achieving low-angle radiation on Top Band, emphasizing the critical role of radial systems and mitigating ground loss. Author VE1ZAC presents EZNEC models illustrating the impact of lumped components and discusses the practical considerations of resonant frequency adjustment and impedance matching for **QRP** operation. The text details the calculation of required loading coil inductance and capacitance, and shares field results, including successful DX contacts on 160m and unexpected excellent performance on 30m.

Operating amateur radio satellites presents unique challenges, particularly concerning antenna design and signal propagation. Juan Antonio Fernández Montaña, EA4CYQ, recounts his three-year journey into satellite communication, starting with initial guidance from EB4DKA. His early experiments involved a portable 1/4 wave VHF antenna with four 1/4 wave ground planes, designed for hand-held use to adjust polarity. This setup, paired with an FT-3000M transceiver, allowed full-duplex operation on **VHF** transmit and **UHF** receive, proving effective for early contacts on satellites like AO27, UO14, and SO35. EA4CYQ's experience highlights the critical role of coaxial cable loss and antenna polarization. After encountering significant signal degradation with longer RG213 runs, he experimented with a 1/2 inch commercial cable, noting improved reception but persistent fading due to varying satellite polarities. This led to the construction of an **Eggbeater II** antenna, an omnidirectional UHF design offering horizontal polarization at the horizon and circular right polarization at higher elevation angles. Subsequent modifications resulted in the directional **TPM2** antenna, which provided sufficient gain for LEO satellites with a wide 30-degree lobe, enabling consistent contacts from his home station. The article concludes with practical insights on the performance of the Eggbeater II for both UHF and VHF, and the TPM2 for UHF, emphasizing their utility for portable and fixed operations. EA4CYQ's journey underscores the iterative process of antenna development and the importance of adapting designs to overcome real-world propagation challenges in satellite communications.

Details the construction and performance of a phase-controlled receiving array, specifically a **MicroSWA** variant, optimized for QRP low band fox hunting on 40M and 80M. The resource documents the author's iterative design process, addressing significant regional noise challenges encountered during 0100-0230 UTC fox hunt periods. Initial experiments involved a director wire on a 40M vertical, yielding limited improvement, prompting a shift towards advanced null-steering techniques. The project leverages concepts from Victor Misek’s "The Beverage Antenna Handbook" and Dallas Lankford’s extensive work on phased receiving antennas for urban lots. A key modification involved integrating a new passive phase control box and a push-pull **Norton common base preamp** using 2N5109 transistors, designed for high third-order intercept performance to maintain weak signal integrity amidst strong adjacent signals. The system incorporates Faraday-shielded transformers with RG174 primaries on -75 ferrite cores, housed in ABS plastic pipe. Performance tests confirmed the MicroSWA's ability to produce deep, steerable nulls, achieving approximately 30 dB noise reduction on 160M, 80M, and 40M. This enabled detection of QRP signals undetectable on conventional transmit antennas. The final unit includes front panel controls, a 10-11 dB preamp, and a robust power conditioner, demonstrating effective noise mitigation for challenging low band QRP operations.

The article describes adding lightning protection to Beverage antennas, which are long wires susceptible to lightning strikes. The author reviews common lightning protection circuits and discusses their components. They then detail their design based on existing methods, highlighting choices for components and reasoning behind them. Finally, the author presents the completed design and its implementation on their Beverage antennas.

SAT filters ensure effective full-duplex satellite QSOs by mitigating interference between 145 MHz uplink and 435 MHz downlink signals. Custom coaxial and SMD-based filters address transmitter harmonic interference and improve receiver isolation, achieving over 70 dB suppression in the undesired band. Designed for simplicity, these filters maintain optimal VSWR and are housed in shielded brass enclosures. Practical implementations with Yagi antennas demonstrate compatibility with SDR systems, enabling seamless communication even in challenging satellite conditions, such as low-elevation passes and DX pile-ups.

This presentation explores the practice of QRP (low-power) amateur radio operation in outdoor settings. It guides operators to identify their specific objectives for portable operations, which inform equipment and antenna choices. The discussion covers considerations including portability, operating modes, power requirements, and weather resistance. Various antenna designs are examined, from vertical configurations to dipoles and end-fed options, with emphasis on deployment practicality in public spaces. The presentation concludes with practical advice on selecting operating locations, RF safety, and resources for equipment and community support for QRP enthusiasts.

The 4m Slim Jim antenna project provides a construction guide for a low-cost, high-performance aerial designed specifically for the 70 MHz FM band. This design achieves a 1:1 SWR across the 4m FM band with straightforward adjustment of the feed point, utilizing RG-58 coax. Its low angle of radiation contributes to effective signal propagation. Construction involves using plastic knitting needles as spreaders and a telescopic fishing pole for support, with components secured using two-part epoxy. Annealed bare single-core copper wire forms the radiating element. The setup process includes raising the antenna at least 3 meters above ground for tuning, adjusting the RG-58 feed point for optimal SWR, and then soldering connections. Waterproofing is achieved with yacht varnish. The design emphasizes low wind resistance for durability, making it suitable for exposed outdoor installations. A PDF construction diagram is available to supplement the written instructions.

Demonstrates the construction of a portable 2-meter repeater system utilizing a **Yaesu DR-1X** transceiver, configured for both analog FM and C4FM digital voice operation. The design emphasizes portability, robustness, and effective thermal management, incorporating a "wind tunnel" airflow system with a fan to maintain transmit module temperatures at 38 degrees Celsius during continuous operation. The system integrates a diplexer, control head, and is housed in a compact, lightweight case weighing under 8kg, designed for single-person deployment. Covers practical considerations for field deployment, including power sources, antenna types, and the overall system architecture for public service events and emergency preparedness. The resource details the modular "wrap around" construction, showing how components like thermal switches for fan control and Anderson Powerpole connectors are integrated. It highlights the system's ability to provide reliable communications support for club activities and emergency communications.

The Anytone AT-D878UVII Plus, a dual-band transceiver, supports both Analog and DMR modes, providing versatile communication options for amateur radio operators. This model is complemented by the Anytone AT-6666 Pro, which delivers a substantial 80W output, catering to users requiring higher power for their radio operations. For mobile and off-road applications, RadioSmart Solutions features a 4x4 Mobile Radio Package Deal, which includes the RTS DV-2135s Mobile Two-Way Radio. This package is specifically designed for reliable communication in challenging environments, often encountered during off-road adventures. An _RSS Rugged Off-Road Antenna_ is also available, engineered to withstand harsh conditions and ensure robust performance. The product range addresses the needs of individuals seeking durable and functional communication solutions for both general amateur radio use and specialized mobile deployments.

SO2R Focus Control and SO2R FC Server are freeware VB6-based tools enabling remote or local control of modern SO2R controllers (supporting OTRSP and MK2R protocols) outside contest logging sessions. The client (SO2R Focus Control) manages serial-connected controllers and can interface remotely via LAN or internet using the optional SO2R FC Server, which supports up to two concurrent clients. Key features include AUX port control with customizable labels, interlock options, AES-256 encrypted network communication, and compatibility from Windows XP through Windows 11. Designed for operators needing flexible station control—especially for remote antenna switching—both programs install cleanly via NSIS and uninstall completely.

Navigating the complex legal landscape of **antenna zoning** and permit acquisition for amateur radio installations requires specific knowledge, which Fred Hopengarten, K1VR, provides through his resource. This content details the essential steps and regulatory considerations for securing permits for antenna support systems and towers. It focuses on the legal and procedural requirements, offering insights into local ordinances and federal regulations that impact amateur radio operators seeking to erect significant antenna structures. K1VR's expertise as a telecommunications lawyer is evident in the practical advice offered, drawing from real-world scenarios in permit applications. The resource equips hams and their legal counsel with the information needed to successfully navigate municipal zoning boards and secure necessary approvals, contrasting with purely technical antenna design guides by emphasizing the administrative and legal pathways to installation.

The W6PQL 23cm Beacon Project describes a **1296 MHz** beacon designed for microwave propagation studies and equipment testing, capable of 30 watts output. It utilizes a PIC 16F628A microcontroller to generate CW and FSK keying for a crystal oscillator, followed by a series of frequency doublers and triplers to reach the target frequency. The final power amplification stage employs a Mitsubishi M57762 module, providing a robust 10-watt RF output. The design emphasizes stability and reliability for continuous operation, with the microcontroller code, written in assembly, provided for customization of the beacon's callsign and message. Originally located in CM97am and aimed at 140 true, the beacon used four 4-foot Yagis stacked vertically for a total ERP of 3kW. The article includes schematics, parts lists, and construction notes to guide builders, along with antenna pattern measurements. Although the beacon itself is no longer in service as of August 2010, the detailed documentation remains a valuable reference for amateur radio operators interested in building similar **microwave** projects or understanding beacon operation.

This excellent resource details the construction and portable deployment of a 40-meter horizontal loop antenna, also known as a 'Sky Loop' or 'DX-Buster'. The design is a modified version of a full-wavelength horizontal loop, adapted for portable use without insulating ropes or egg insulators. The article describes the use of four 5-meter heavy-duty squid poles and metal post bases for support, allowing for rapid setup. Antenna wire length is specified at approximately 43-45 meters for 40-meter operation. The construction method involves winding the wire around rubber caps on the squid poles, secured with electrical tape. This technical documentation provides specific material choices and assembly techniques for a field-deployable 40-meter loop antenna, suitable for operators seeking a portable solution for the **40-meter** band. The design focuses on minimizing parts for ease of transport and assembly, utilizing readily available components like fiberglass squid poles.

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