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Operating marine mobile with antennas for 15-17-20 meters band.

Duoband Yagi 2m/70cm with 4 Elements on 2 m and 5 Elements on 70 cm and one Feed point. The 4-El.-Ultralight-Yagi for 2m can be used on 70cm with an SWR of 1,5 without any changes.

If your multiple transceiver station is suffering of intrastation interference, this handy and inexpensive band pass filters and help you. QST article Sept 1988

A ham radio home made preamplifier for 50 MHz and 70 MHz bands

This article introduces an Arduino-based QRP CW Transceiver designed for lower HF bands. The journey begins with the Wotduino, evolving from a keyer to a multi-mode beacon. The development includes a QRP transmitter and culminates in a receiver inspired by Roy Lewallen design. The transceiver, controlled through a control bus features a signal path, modulation, filtering, and adjustable frequency settings. Despite initial testing intentions, successful QSOs on 80 and 40 meters showcase its functional capabilities.

A dual band X-frame wire antenna made using 4 turns for response down to 3 MHz or so, and 2 turns (switched) for response up to around 18 MHz. The loop configurations are tuned using common eBay 365 pF tuning caps.

A homebrew 13 elements yagi antenna for two meters band. These project includes two model of the same antenna with a 6 and 7 meter boom length. Detailed pictures and nec files are available for download

A dual band 40-80 vertical antenna on an 18m Spiderbeam Fiberglass Spiderpole, with monoband performance

A coaxial cable trap is a fundamental component in multiband antenna design, enabling a single radiator to resonate efficiently on multiple frequencies by electrically shortening or lengthening the antenna element. This project focuses on constructing such a trap for a vertical antenna operating on the 10 MHz (30m) and 14 MHz (20m) amateur bands, providing practical insights into its fabrication and integration. The article outlines the specific dimensions and winding techniques for the coaxial trap, emphasizing the use of readily available materials. It details the physical construction of the vertical element, including the mast and radiating sections, to achieve optimal performance across both target bands. The author shares personal experiences with similar trap designs, noting their effectiveness in previous horizontal dipole configurations. Key construction steps are illustrated with _original photos_, showing the assembly of the trap and its incorporation into the overall antenna structure. The design aims for a compact footprint, making it suitable for limited space installations while still delivering effective DX capabilities on the **30-meter** and **20-meter** bands.

The DK7ZB-Dualband-Moxon-Beam provides a compact, high-performance antenna solution for 28 MHz and 50 MHz operations, utilizing a single 50-ohm feedpoint. This design functions as a mini-beam on 10 meters, achieving a gain of **4.0 dBd** with a front-to-back ratio of _30 dB_, while operating as a 2-element Yagi on 6 meters, yielding a gain of **4.3 dBd** and an 11 dB F/B ratio. The antenna's dimensions are approximately two-thirds that of a full-size 10-meter beam, making it suitable for smaller spaces. Construction details include a parts list specifying aluminum tubes of various diameters and lengths for the reflector and radiator elements. Builders like Aleks (S54S) and Marcio (PY2OK) have successfully replicated the design, with Aleks noting the utility of bending corners during assembly. Fine-tuning is accomplished by adjusting the length of specific elements that slide into larger tubes. The feeding system incorporates a balun, with options for either 300 watts using RG188 on an FT140-43 core or 1 kilowatt using _Aircell-5_ on an FT240-43 core, ensuring versatility for different power levels.

Operating within the low-frequency spectrum, transformers serve critical roles in antenna systems, particularly for 160m applications. The resource details the construction and performance of 1:1 transformers built on BN-73-202 cores, emphasizing their use as hybrid combiners or phase inverters for RX antenna arrays. Measurements reveal that these transformers exhibit minimal losses, around 0.12 dB at 1.8 MHz, with variations based on wire type and number of turns. The analysis includes comparative data on transformer performance, highlighting the impact of different winding techniques on frequency response. Notably, the use of coaxial cable for winding improves bandwidth while maintaining low-frequency efficiency. The resource also discusses braid breaker transformers, which minimize inter-winding capacitance, achieving low losses around 0.21 dB at 1.8 MHz. These insights are crucial for optimizing low-band antenna systems, allowing operators to make informed decisions regarding transformer design and implementation.

Constructed in May 2008, this innovative 4m tall electrically full-size halfwave vertical dipole, tunable to multiple bands, offers HF coverage despite its space-saving design. Inspired by cost-effective DIY alternatives, the antenna design departs from conventional center-fed approaches, utilizing asymmetrical dimensions. Despite resonance challenges, the antenna's performance remains viable, boasting broad bandwidth and adaptability, as demonstrated through SWR measurements and EZNEC predictions.

This document details the construction of a multi-band end-fed antenna, suitable for situations with limited space for larger antennas. The design utilizes a 1:49 to 1:60 impedance transformer to match a half-wave wire antenna fed at one end. Compared to a traditional dipole, this antenna resembles a highly unbalanced Windom antenna with one very long leg and a virtual short leg. The design eliminates the need for radials but relies on the coax cable shield for grounding. The document recommends using at least 10 meters of coax and installing a common mode filter at the entry point to the shack for improved performance.

This antenna works on 17, 20, and 30 meters, with the best bandwidth on 20 meters. The bandwidth on 17 and 30 is quite small but usable. There is a 20 KHz bandwidth on 20 meters.

Learn how to design and analyze a folded trifilar antenna for the 80-meter band. Based on a description from RAF antennas between 1940 and 1970, this article provides step-by-step guidance on modeling the antenna, calculating resonance frequency, adjusting dimensions, and verifying performance. Perfect for hams looking to improve their antenna setup for better transmission and reception on the 80M band.

The reason for making this antenna was the desire for a vertical (hence DX-ish) antenna that would cover at least 20m that would fit on my 5m fishing pole. This antenna can work on 20m 17m 15m bands and it is suitable for SOTA operations

Integrating a **160-meter vertical wire antenna** with an existing 80-meter Yagi system presents unique challenges for Top Band operation. This project outlines the author's experiences with seasonal antenna removal and reinstallation, a necessary task for agricultural land use. It details specific issues encountered, such as incorrect coil sizing and relay configuration problems, providing practical insights into common pitfalls. The article describes the iterative tuning process, comparing **NEC model** predictions with actual on-air performance. It emphasizes the importance of precise measurements and adjustments to achieve optimal resonance and impedance matching. The author shares lessons learned from troubleshooting, including the impact of ground system integrity and feedline considerations. Concluding with an antenna checkup, the resource addresses long-term maintenance aspects, including galvanic corrosion prevention and general upkeep for reliable operation.

A comprehensive overview of a 10-band attic antenna system developed for contesting and DXing is presented, covering its evolution and performance. Initially intended in a restricted location, the system has been developed through numerous iterations, using various antenna types such as delta loops and Yagis. Automatic switching, dual-direction capability, and optimum tuning for certain band segments are among the most notable features. The project not only improves operating efficiency but also provides great learning opportunities in antenna design and installation in restricted places.

Presents an interactive **Ham Bands Explorer** web application, offering a live view of all amateur radio bands overlaid on a world map. This resource displays **CQ zones** and **ITU zones**, with geographical data sourced from HB9HIL/hamradio-zones-geojson under an MIT license. The interface provides a dynamic visualization of global band conditions, enabling operators to observe activity patterns across different regions. Users can select individual countries to retrieve and display their specific band plans, with frequency coverage details loaded from CountryData.json. The tool indicates 100% frequency coverage, ensuring comprehensive data presentation for selected regions. This functionality supports detailed analysis of national regulatory variations within the amateur spectrum. The application integrates both a map view and a live view, facilitating real-time monitoring and geographical context for band usage. It serves as a practical reference for understanding international amateur radio regulations and visualizing propagation characteristics across various frequency allocations.

Hamradio_copilot is an open-source tool designed for DXers and contesters who need real-time situational awareness. It is ideal for operators who want to visualize propagation trends instantly rather than scrolling through raw text streams of cluster spots. Rally acting as a copilot for your station, this tool transforms raw data into actionable intelligence. By visualizing Signal-to-Noise Ratios (SNR) across different bands, it helps operators make quick decisions on which band to prioritize or where to point their antennas, effectively showing not just who is on air, but where the propagation is currently open from your location. This is a fantastic information for avid contesters. The software aggregates data from two primary services: - Reverse Beacon Network (RBN) via Telnet. - PSK Reporter via MQTT feeds. It processes this data to generate a comprehensive HTML report featuring SNR heatmaps and statistical breakdowns by ITU Zone. Users can filter data by specific zones or country codes (ADIF), analyze historic time ranges, and optionally integrate solar weather data. The complete source code is available on GitHub, allowing for community customization. It is written in Python and uses SQLite for data management.

This article describes the construction of a simple dual-band VHF/UHF end-fed vertical dipole antenna designed for local repeater access using an Icom IC-705 radio. Built from a single piece of RG58U coaxial cable, the antenna consists of a 460mm exposed inner conductor, 450mm of intact coax, and a 9-turn choke balun wound on a 27mm former. Mounted on a 10m Spiderpole, the antenna achieves excellent SWR readings (<1.2:1 on 2m, <1.5:1 on 70cm) and provides effective coverage of local repeaters with unexpected reach into distant locations.

Vertical antenna tests at the Sonten-Rancabali tea resort in Ciwidey, West Java. The assembly, led by Mr. Dian Kurniawan and the team, took just 20 minutes. Mrs. Mita performed the transmit check-in test, which was received across various regions in Indonesia, including Sulawesi, East Java, and Bangka Belitung. The team will release a video of the test soon and has thanked colleagues YB3HRY and YB0BAW for their reports.

This page provides a detailed step-by-step guide on building a 70 cm band repeater antenna for hams. The instructions are clear and easy to follow, making it suitable for both beginners and experienced operators. The antenna design is optimized for the 70 cm band, ensuring efficient communication for local repeater systems. Whether you're looking to improve your repeater setup or just starting out in amateur radio, this guide will help you build a reliable and effective antenna for your station.

Cavity is often required at a busy site to not only prevent its receiver from being overloaded by off-frequency signals, but also be a good neighbour and prevent low-level signals from your transmitter from getting into other users receivers - not to mention the preventing of those other signal from getting back into your transmitter to generate spurious signals in its own right.

Amateur radio courses teach that in amplitude modulation, sidebands arise. This can be proven mathematically, and nowadays with an SDR one can easily see them.

Learn how to build a simple tuned loop antenna for the AM broadcast band to improve the performance of your radio receiver. Discover how to construct a loop antenna with readily available materials, such as balsa and basswood, without the need for specialized woodworking tools. Follow step-by-step instructions to create a portable loop antenna that offers good gain and directivity, ideal for pulling in weak stations. Enhance your Ultralight DX'ing experience and explore the world of FSL antennas through this practical DIY project.

WB8LZR details the construction and initial field results of a multi-band vertical wire antenna, designed to complement his existing horizontal loop for improved DX on 80 meters. The antenna utilizes a 67-foot vertical wire, configured as a quarter-wave radiator on 80m, and employs a 1:1 current balun for RF isolation on 80m, 30m, and 17m. For bands like 40m, 20m, and 10m, where the wire acts as a half-wave or full-wave radiator, an additional impedance transforming _unun_ is integrated to manage the significantly higher feedpoint impedance and voltage. The author notes the vertical's performance as a receiving antenna, observing reduced noise compared to his main horizontal loop, particularly on 80m, and even hearing some long-path signals the loop missed. Initial QRP contacts, including a **1-watt** QSO with a _VP2 station_ on 30m, demonstrate its transmit capability. While the radial system is currently rudimentary, the project outlines practical considerations for multi-band vertical deployment and impedance matching.

This guide provides detailed information on designing a 5 Band Quad Antenna for ham radio operators. It covers the necessary materials, dimensions, and construction steps required to build the antenna. The guide aims to help hams optimize their antenna setup for maximum performance on five different bands. Whether you are a beginner or an experienced operator, this resource can assist you in creating an effective antenna system for your station.

This PDF article introduces a series of dual-tuned bandpass filters designed for input tuning in amateur band receivers. Developed by Stefen Niewiadomski, these filters feature 50-ohm input/output impedance and can be cascaded for improved roll-off outside the passband. The designs use readily available TOKO coils, with taps on the tuned winding for matching input circuits with impedances around 1k ohm. The inductors are core-tuned, with average inductance values provided for easier matching to other inductors.

The CW typewriter is a compact adapter board that transforms Morse code into ASCII characters using an Iambic key. It connects to a computer via USB, emulating the keyboard. The device features inputs for Iambic keying and a WPM speed potentiometer, and outputs for a key and a speaker for side tone. The device can be used with various software and online typing games for practice, offering a unique and interactive way to learn and use Morse code.

An cheap and efficient wire antenna for lower HF bands. This closed loop antenna, radiates perpendicular to its plane with a bi-directional radiation pattern. With a gain of 2 dB over a diplole it is a low noise sensible antenna. Requires a tuner if you want to use as a multiband antenna.

Learn how to build a portable receiving antenna for the 160 meter band. This guide provides detailed instructions on constructing a loop antenna using a coaxial cable RG-316 with SMA connectors. The antenna weighs 1.7 kg and has dimensions of 2m in height and 1.892m in width. The wooden frame consists of four 0.945m long pieces and two 1m long pieces. Perfect for hams looking to enhance their 160m band reception during travel or portable operations.

This study details a reception comparison between vertical and horizontal active loop antennas, specifically two identical _Wellgood active loop antennas_, on various HF bands. The experiment, conducted in a densely populated QRM-prone area, monitored FT8 signals over a 24-hour period using two identical receivers. The methodology involved direct comparison of signal reception across the HF spectrum, aiming to identify performance differences based on antenna orientation. The results indicate that vertical loops demonstrated superior performance on higher bands (10m, 15m, 20m), while horizontal loops excelled on lower bands (30m, 40m, 160m), particularly for receiving long-distance (DX) signals. The horizontal loop's advantage on lower bands is attributed to potentially better low-angle performance and reduced sensitivity to man-made noise, yielding a **2-3 S-unit** improvement on 160m. The study provides practical insights for optimizing antenna placement in challenging urban environments, noting that the horizontal loop consistently showed a **10-15 dB** signal-to-noise ratio improvement on lower bands.

Learn how to improve reception on the hf bands by setting up a noise cancelling system that nulls out local interference. This article describes a system using a 'Main Station Antenna' to receive a wanted signal and associated QRM, and an 'Auxiliary Antenna' to pick up unwanted interference. Gain and phasing controls are used to reduce/remove interference, leaving only the wanted signal. Tips are provided based on the author's personal experience, applicable to commercial noise cancelling products, kit form, or homebrew setups. Discover the importance of configuring the 'Auxiliary Antenna' to optimize your system and improve readability of wanted stations.

Four distinct amateur radio bands, specifically 40, 30, 20, and 15 meters, are addressed by a portable dipole antenna design. This antenna utilizes a manual switching mechanism, employing "fast-on" or flying connectors to change bands. The design is presented with an animated plan, illustrating how operators can adjust the operating frequency by opening and closing specific connections on the antenna elements. The resource describes a _4 savos dipol_ (4-band dipole) that can be shortened for specific band operation. It provides practical information for hams seeking to construct a versatile, multi-band wire antenna for portable operations or fixed station use. This design offers a straightforward approach to achieving multi-band HF capability without complex tuning units, making it suitable for field deployments like SOTA or POTA activations where rapid band changes are beneficial.

The Portable EFHW antenna for the 40, 20, 15, and 10-meter bands utilizes a broadband transformer with a 1:49 ratio, designed on a PCB by either Jan or DL2MAN. The design incorporates an **FT114 core**, offering an alternative to the FT82 core. The antenna requires precisely 20.5 meters of DX Wire Ultralight for optimal performance. Additional components include DX Wires "Dyneema" 1mm rope and 1mm bricklayers string for structural support. The SWR plot indicates performance at two elevation heights: 5.5 meters (blue line) and 4 meters (yellow line), demonstrating optimization for low-elevation portable use without poles. The antenna's components, including spool and rope tensioners, are available for 3D printing, with spool dimensions scaled to 130% for a length of approximately 110mm. The design emphasizes simplicity and portability, suitable for field deployment.

A 13-foot total radiating element length is achieved by combining a Buddipole Long Telescopic Whip with 4 feet of modified tripod tubes, forming a low-profile, multiband antenna for **POTA** operations. The resource details the transformation of an Amazon Basics Aluminum Light Photography Tripod Stand, focusing on electrically isolating the top two radiating sections from the bottom support. John, VA3KOT, outlines component sourcing, including the 9-foot 4-inch fully extended whip, and emphasizes using adhesive copper tape for reliable electrical contact and conductive grease to prevent oxidation at tube connections. The construction process, while not requiring specialized tools, highlights careful assembly to ensure proper electrical conductivity and mechanical stability. The author's experience with this setup suggests its effectiveness for portable activations, offering a discreet profile compared to larger antenna systems. The design prioritizes ease of deployment and transport, making it a practical solution for operators seeking a compact yet versatile antenna for field use.

Discover the best low band receive antennas for hams with limited space. Learn about the K9AY loop antenna and Shared Apex Loop Array, two alternatives to the traditional Beverage antenna. Understand the concept of Relative Directivity Factor (RDF) and compare the performance of different receive antennas. See how the Shared Apex Loop, patented by Mark Bauman (KB7GF), offers an RDF between 8 and 10dB. Find out how to optimize antenna performance and enhance your receive capabilities on 160, 80, and 40 meters. Explore the world of low band receive antennas with insights from WB5NHL Ham Radio.

This is a 50 MHz WebSDR receiver, located in Ashford, CT, USA FN31VU using a deltaloop turnstile horizontally polarized omnidirectional antenna.

Presents an interactive online **Moxon antenna designer** tool, enabling radio amateurs to configure and analyze lightweight Moxon antennas for HF and VHF bands. Users can specify design frequency, element lengths, wire diameter, insulation, and support height. The tool visualizes the antenna in interactive 3D graphics and generates comprehensive performance charts, including azimuth, elevation, 3D, and polarization radiation patterns, VSWR charts, antenna current diagrams, and Smith charts. It also allows selection of various ground types (e.g., very poor soil, salt water, free space) to model environmental effects on antenna performance. The designer provides insights into how physical dimensions and ground conditions influence key antenna parameters like forward gain, front-to-back ratio, and feed-point impedance, which is typically close to 50 ohms. It also includes a feature to model the effect of coaxial cable losses on **VSWR** at the transmitter end, distinguishing it from the feed-point VSWR. This helps operators understand the actual radiated power efficiency versus the apparent match at the transceiver, offering a practical perspective on antenna system performance in portable operations.

Documents the design and construction of a **four-band Moxon beam** antenna, covering 20, 15, 10, and 6 meters. Author W7JMP shares his journey from initial research and computer modeling using 4NEC2 to the final on-air testing and optimization. The project aimed for gain over a dipole on 20 meters, with a budget under $500, including the antenna rotor. The design incorporates fiberglass spreaders and a single feedpoint, avoiding complex relay switching. The article details the selection of materials, assembly techniques, and the critical tuning process. W7JMP describes fabricating the hub, mounting spreaders, and attaching elements made from stripped THTN wire. A notable innovation is the use of a half-wave tuning stub with a loading coil for in-situ adjustment of the 20-meter reflector, optimized via remote S-meter readings using a webcam and smartphone. This method allowed for fine-tuning the **front-to-back ratio** without lowering the antenna. Initial testing revealed a dipole-like pattern, which was significantly improved after tuning, resulting in reported 2 to 4 S-unit front-to-back ratios and enhanced signal strength for DX contacts on multiple bands, including sporadic E on 10 and 6 meters.

Demonstrates the ZS6BKW multiband HF antenna, a design by ZS6BKW (G0GSF) that improves upon the G5RV by offering direct resonance on multiple bands without an antenna tuner. The resource details the antenna's 90-foot length and 40-foot 450-ohm twin lead downlead, emphasizing its suitability for hams with limited space or budget. It covers both horizontal and inverted-V configurations, noting the inverted-V's single-support advantage and the importance of maintaining an apex angle of at least 90 degrees to prevent signal cancellation. The author, G3UKV, shares his preference for 450-ohm twin lead over 300-ohm due to its superior strength and lower losses, especially in wet conditions, drawing from his extensive field experience. The document presents recorded SWR and impedance (R) measurements taken with an MFJ Antenna Analyzer, confirming excellent performance on 40m, 20m, 17m, 12m, 10m, and 6m, often with SWRs below 1.3:1. It also discusses the antenna's tunability on 80m with an ATU and suggests a method for 160m operation. G3UKV recounts receiving "excellent reports" on 7 MHz and 14 MHz, validating the antenna's effectiveness. Practical advice includes keeping antenna ends clear of ground by at least a yard to avoid detuning and the recommendation of a 1:1 current balun where the 450-ohm feeder connects to 50-ohm coax.

The project details the construction of a portable multiband mobile antenna, designed for rapid deployment with an _Elecraft KX3_ for /M operations. It utilizes a coil and the car body as a counterpoise, enabling operation across multiple HF bands. The article presents a table of coil tap positions for 40m, 20m, 17m, 15m, and 10m, along with corresponding SWR measurements, demonstrating an SWR below 1.5:1 on all tested bands. Photographs illustrate the antenna's components, including the coil winding and mounting mechanism, and its deployment on a vehicle. The author provides insights into the antenna's performance characteristics, noting its resemblance to a vertical dipole despite the unconventional ground plane. The resource includes a parts list and construction steps, making it reproducible for other radio amateurs.

The multiband tuned doublet, or center-fed Zepp, is a simple and efficient HF antenna that operates effectively across most amateur bands using a balanced parallel-wire feedline and antenna tuner. Unlike coax-fed dipoles, it tolerates impedance mismatches with minimal loss. By selecting suitable feedline and dipole lengths, one can achieve stable multi-band operation. While it doesn’t match monoband Yagis, it offers excellent performance, low cost, and broad coverage. Its radiation pattern and efficiency vary with frequency, but it remains a practical and versatile solution for HF operators.

Thunderstorm effects on sporadic E propagation, Very long distance propagation in the 144 MHz band, Analysing the number of skips in multiple hop propagation

This article details a ham radio operator’s experience setting up HF antennas in an antenna-restricted community. Initially using an AEA Isoloop magnetic loop for QRP PSK, the author later built an attic antenna system, including dipoles for multiple HF bands and a slinky dipole for 40 meters. The setup allowed for operation on six bands with acceptable VSWR. Despite space constraints and some compromises, performance was effective. The article highlights practical strategies, emphasizing experimentation and antenna modeling for optimizing performance in limited-space environments. A valuable guide for ham radio operators facing similar restrictions.

In his journey to improve Morse code skills, the author developed a straightforward device named the Tiny Keyer using Arduino. Tailored for Morse code enthusiasts and ham radio operators, this project utilized the budget-friendly Arduino ATTiny 85 Kickstarter board. With straightforward setup procedures in the Arduino IDE, the Tiny Keyer's small size and low cost make it accessible for beginners and hobbyist clubs interested in Morse code exploration.

The author recounts their journey in ham radio, including the initial experience with Morse code. Now retired, he has rekindled his interest in ham radio and CW. Here share his project of constructing an Iambic Keyer with Arduino. The project includes a memory keyer and speed adjustment. Additionally, the author provides resources for an Arduino enclosure available on Thingiverse, enhancing the project aesthetics and functionality.

The author describes his experience building and using a Beverage antenna for the 40-meter band. Despite encountering some challenges, the antenna offered some improvements in receiving stations compared to a 3-element inverted Vee antenna. The Beverage antenna showed a significant daytime signal-to-noise ratio improvement and received signals better than the Vee antenna. However, the front-to-back ratio was not ideal, and the transmit power seemed to affect the Beverage antenna. Overall, the author concludes that the Beverage antenna might be more suitable for locations with higher noise levels. The total cost of the antenna was around 30 Euros.

This project details the design and construction of a Spider Quad antenna for HF bands (20m, 17m, 15m, 12m, and 10m). The boomless structure optimizes driver and reflector spacing, enhancing performance. Tuning and impedance matching were refined using antenna analyzers and a 1:2 balun. Final tests confirmed excellent SWR and gain, making this an efficient solution for top performance DXing.