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This 6 meter 2 element yagi antenna is simple, compact and effective antenna for 50 Mhz. The design antenna was optimized with AO for best match to 50 ohms, no matching network. A choke balun is recommended to decouple feedline currents.

This web article details the construction of a 4-meter band coaxial dipole antenna, designed for operation between **70.000 MHz and 70.500 MHz**. The resource provides a bill of materials and step-by-step assembly instructions for a half-wave dipole constructed from _RG-58_ coaxial cable. The design specifies a direct 50 ohm feedpoint impedance, eliminating the need for an external matching network. Construction photographs illustrate the stripping and soldering processes for the coaxial cable elements, ensuring proper electrical connection and physical integrity. The article includes specific dimensions for the radiating elements, derived from calculations for the 70 MHz band. The project outlines the physical dimensions required for resonance at 70 MHz, with the outer braid forming one half and the inner conductor forming the other. The feedline connection is directly to the coaxial dipole's center, maintaining a 50 ohm characteristic impedance. While the article does not present SWR plots or VNA sweeps, it focuses on the mechanical construction and dimensional accuracy for achieving a functional 4-meter dipole. The design is intended for fixed station use, with no specific mention of polarization or height above ground, but implies a standard horizontal orientation for dipole operation. DXZone Focus: Web Article | 4m Coaxial Dipole | Construction Guide | 50 ohm Feed

1:49 UNUN using two stacked FT240-43 cores for end fed halfwave antenna. To match the end fed half wave antenna to the coaxial feeder, it is necessary to have a matching network or transmission line transformer.

How to setup a proper antenna feed line with a particular attention to RFI by K0GKJ

A 102-inch vertical whip, commonly a CB antenna, forms the core of this low-profile 10-meter antenna design, optimized for the 28 MHz band. The construction details specify three 8-foot radials made from scrap wire, connected to a common point. This simple yet effective setup is designed for ease of construction and deployment, making it accessible for operators with limited space or materials. The design emphasizes using readily available components, including PVC pipe for the mast and a SO-239 connector for the feedline, ensuring a straightforward build process for a resonant quarter-wave vertical. Field results indicate that this antenna provides good performance for local and DX contacts on 10 meters, despite its compact footprint. The author, N8WRL, shares practical insights into its construction and tuning, highlighting its suitability for temporary or permanent installations where a full-sized antenna might be impractical. Comparisons to more complex designs suggest that this low-profile vertical offers a respectable signal-to-noise ratio and effective radiated power for its size, proving that simple designs can yield satisfying on-air results.

Presentation about Practical Antenna Modeling Using the NEC Codes with examples of HF wire antennas and 4NEC2. How to define and edit the models, Running the simulations, Work some examples, Variables usage, Deal with Feed Lines and ground

Constructing a digital interface for the Elecraft K2 transceiver, this resource details the "Fat Wire" design by WG4S. It demonstrates how to integrate a sound card for digital modes, outlining specific connections to the K2's microphone jack and internal audio path. The author shares practical insights from his build, including the use of _RG-62_ coax for its flexible braid and the strategic placement of components like the 2.2K resistor and _2N2222_ transistor. The guide provides a breakdown of the interface's internal wiring, specifying connections for AF In (pin 1), AF Out (pin 5), PTT (pin 2), and Ground (pin 7) on the K2's microphone connector. It also covers the external connections to a laptop's headphone and line-in jacks, along with a DB-9 connector for PTT control via _DTR_ or RTS lines. The author notes that his laptop's headphone output level was sufficient for the K2, negating the need for an attenuator. Reflecting on the design, the author, Dan WG4S, acknowledges a later suggestion to house the components directly within the DB-9 shell for a more compact build. This iterative feedback highlights the ongoing evolution of DIY ham radio projects and the community's collaborative spirit in refining designs.

Transferring Radio Frequency Energy from Your Transmitter to Your Antenna by Don Keith N4KC

A simple dipole for 40m band feeded with 450-Ohm openwire feedline includes MMANA Gal files to download

Online calculator for J-Pole antennas. The J-pole antenna consists of a short and a long vertical pole with a feed point near the bottom. The antenna looks like the letter J, hence the name J-pole antenna.

A dipole can be broadbanded by a number of techniques including by matching with resonant sections of transmission feed lines.

Listen to online police scanner from Douglas County in Oregon USA

A portable wire antenna for the HF bands, made with a common speaker wire. In its natural form, the speaker wire acts as parallel feed line coming up to the bottom of the PVC feed point. From there, it's split into two wires, one heading out each side of the PVC tee.

The IZ3MEZ Web DX Cluster presents real-time amateur radio DX spots across 20 distinct frequency bands, spanning from **LF (2190m)** at 135.7 kHz up to **SHF (QO-100)** at 10499 MHz. It displays the DX callsign, frequency, DXCC entity, spotter callsign, and spotter DXCC entity, along with any accompanying comments. The cluster also lists various operating modes such as CW, RTTY, FT8, FT4, FT2, PSK, and SSTV, and supports special operating activities like QRP/P and specific award programs including IOTA, POTA, SOTA, WCA, and JOTA. The cluster's interface provides a dynamic feed of the latest 50 spots, continuously updated with precise timestamps. It offers direct **Telnet protocol** access for users preferring a command-line interface, with configuration instructions provided. The resource also integrates with other spotting networks like RBN and PSK Reporter, enhancing its utility for DXers and contesters seeking propagation information and activity monitoring across a broad spectrum of amateur radio frequencies.

If you ever asked if you need an Unun or a Balun this article is for you. The right question should be do I need a feed line choke or an impedance transformer whose output is configured as balanced or as unbalanced. An impedance transformer can be configured as a voltage transformer or as a current transformer.

How to handle feedline radiation issues

This paper discusses the sources of feed line currents and the methods used to control them.

Experimenting a low impedance feedline by G3TXQ

The resource, "Conventional Use of Transmission Line," meticulously details the operational principles of transmission lines, emphasizing the Transverse Electromagnetic (TEM) mode of energy transfer. It clarifies that for a line to function purely as a transmission line, all currents must be confined internally, with external fields ideally zero. The discussion differentiates between balanced and unbalanced lines, asserting that while both require equal and opposite currents within the conductors, the key distinction lies in the voltage relationship of each conductor to the surrounding environment. It highlights that a good antenna pattern does not inherently confirm proper feeder balance, and that common-mode currents can lead to RF in the shack and increased noise levels, even without pattern distortion. The article further explains that a transmission line can become a radiating conductor if energy is applied in a non-TEM mode, leading to common-mode issues. It cites classic texts like Jordan and Balmain's "_Electromagnetic Waves and Radiating Systems_" and Kraus's "_Antennas_" to support its definitions of TEM mode operation. The content also explores non-transmission line applications of parallel or concentric conductors, such as _coaxial dipoles_ and _folded dipoles_, which intentionally operate in non-TEM modes for antenna functionality. The author, _W8JI_, stresses that simply measuring equal currents is insufficient to confirm a balanced feeder; phase and voltage balance to ground are equally critical.

Constructing an End-Fed Half-Wave (EFHW) antenna offers a practical solution for HF operators seeking a multiband wire antenna without the need for extensive radial systems. This design typically employs a high-impedance transformer at the feed point, matching the antenna's inherent high impedance to a 50-ohm coaxial feedline. The article specifically details a 2012 approach, focusing on a transformer with a 49:1 turns ratio, which is a common configuration for EFHW antennas. The resource outlines the construction of a wire element cut for a half-wavelength on the lowest desired band, with specific coil arrangements enabling operation on harmonically related bands such as 40m, 20m, and 10m. It discusses the physical dimensions and winding details for the matching transformer, often utilizing a ferrite toroid core to achieve the necessary impedance transformation. The content provides insights into the operational principles and practical considerations for deploying such an antenna, including methods for tuning and optimizing performance across multiple amateur radio bands. While acknowledging that the presented information from 2012 may be superseded by newer insights, it serves as a foundational reference for understanding EFHW antenna theory and construction.

Common mode currents can flow in all sorts of systems, not just antenna feed lines. This article explain how Common mode noise can be isolated from the desired signal

TIM-CO, an authorized distributor, offers a range of electronic components crucial for various applications, including amateur radio station builds. Their inventory focuses on **connectors**, both commercial and military-grade, which are essential for robust and reliable interconnections in radio equipment and antenna systems. This includes a variety of types suitable for RF applications, ensuring signal integrity. Beyond connectors, TIM-CO provides passive and electromechanical components, fundamental building blocks for any radio circuit or control system. These components are vital for constructing filters, impedance matching networks, and power distribution systems within a shack. Their selection supports both new construction and repair of existing gear. Additionally, the company supplies **RF-coax cable assemblies**, pre-fabricated solutions that save time and ensure proper termination for feedlines and inter-component connections. These assemblies are critical for minimizing signal loss and maintaining impedance matching from the transceiver to the antenna.

The Tri-pole antenna, a clever modification of a standard dipole, allows for dual-band operation by integrating a third element. This design effectively shortens the overall dipole length by 10 to 20 percent, simplifying antenna rotation and offering a compact footprint. KK4OBI's article delves into the operational principles, using a 6 and 10-meter Tri-pole as a primary example, and provides comprehensive instructions for constructing any Tri-pole antenna within the 6 to 15-meter range. Key to the Tri-pole's performance is its off-center feed, necessitating a common mode choke at the feed point for optimal tuning and reduced noise. The author outlines a methodical approach to determining element dimensions, starting with a vertical element frequency calculated as 0.47 times the sum of the desired upper and lower band frequencies. This calculation, along with K-values derived from trend lines, guides the initial lengths for the horizontal arms, demonstrating how a 10m-6m Tri-pole can achieve a total horizontal length 78% shorter than a conventional 10-meter dipole. Tuning and balancing are critical, with the article detailing adjustments to arm lengths and the vertical element to achieve balanced SWR values, as validated through 4NEC2 simulations. Radiation patterns are analyzed at various elevations, showing gains around 5.7 dBi and favorable take-off angles for DX contacts. Construction details specify aluminum tubing dimensions, U-bolts, and an SO-239 connector, emphasizing the importance of a ferrite-based choke for wideband operation.

RF Feedline (Coax and Ladder-Line) Loss and ERP Calculators made with Javascript. This complex feddline loss calculator has already several line types paramenters for most common coaxial cables from Belden, Time LMR, Wireman and other common products. Result will give Matches loss, SWR loss, dB and Watts power loss.

Voldatech, a manufacturer based in China, produces a range of RF feeder cables and site components essential for amateur radio installations and telecommunication infrastructure. Their product line includes various types of coaxial cables, such as **50 Ohm** and 75 Ohm options, along with a comprehensive selection of connectors like N-type, UHF, and BNC. These components are critical for maintaining signal integrity and minimizing loss in antenna systems, whether for a home shack or a remote DXpedition setup. The company's focus on _RF Coax cables_ and connectors directly supports the needs of radio amateurs seeking reliable transmission lines for their transceivers and antennas. Amateurs often compare Voldatech's offerings to established brands, evaluating factors such as impedance matching, shielding effectiveness, and durability under various environmental conditions. The availability of diverse cable types allows operators to select optimal solutions for different frequency bands and power levels, from QRP to high-power amplifier setups. Their products are particularly relevant for those constructing new antenna arrays or upgrading existing feedline systems, aiming to achieve maximum power transfer and reduce standing wave ratio (SWR) for efficient signal propagation.

The DIY 137 MHz WX SAT V-dipole antenna project details the construction of a specialized antenna for receiving weather satellite transmissions. It provides specific dimensions for the dipole elements, designed for optimal reception around the 137 MHz band, which is commonly used by NOAA and Meteor weather satellites. The resource outlines the materials required, such as aluminum tubing for elements and PVC for the support structure, along with the necessary coaxial cable and connectors. The article presents a clear, step-by-step assembly process, including how to form the V-shape and connect the feedline. It emphasizes practical considerations for mounting and weatherproofing the antenna for outdoor deployment. The design focuses on simplicity and effectiveness for amateur radio operators interested in satellite imagery. Key aspects include the precise angle of the V-dipole and the lengths of the radiating elements, which are critical for achieving the desired circular polarization response for satellite signals. The resource includes photographic documentation of the construction phases and the final mounted antenna.

PRO-LINK specializes in the manufacturing and distribution of high-quality cabling solutions, including a wide array of fiber optic cables and various coaxial cable types. Their product line encompasses 50-ohm and 75-ohm coaxial cables, essential for diverse RF applications, alongside specialized RF cables and 10Base-T networking cables. The company also provides a selection of connectors and custom cable harnesses, catering to specific installation requirements. Since 1988, PRO-LINK has offered a 5-year warranty on its products, underscoring a commitment to durability and performance. The product catalog details specifications for different cable constructions, such as _RG-58_, _RG-213_, and _LMR-400_ equivalents, which are commonly used in amateur radio installations for antenna feedlines and inter-component connections. Their offerings support both commercial and amateur radio operators seeking reliable signal transmission. The company's focus on robust cable and connector solutions addresses the critical need for low-loss transmission lines in radio communication systems, ensuring signal integrity across various frequency bands.

Building A Full-Wave Quad Loop Antenna for 6 Meters. This is an easy antenna to build and the materials cost about $15-20. It exhibits 1.8dB gain over a 1/2-wave dipole. Using an open-wire parallel feedline (commonly called ladder line) with an antenna tuner, it tunes up on the 10m band as a 5/8-wave loop as well

Undestanding and measuring SWR, Standing Wave Ratio in antenna feed lines. This article also introduce basic concepts and usage guidelines of amateur radio antenna tuners

Essentially, a J-pole is a 1/2 wave resonant antenna connected to a quarter wave matching stub. The feedline is connected at a point on the matching stub that is at the feedline's characteristic impedance. The result is 3/4 of a wavelength on one side and 1/4 wavelength on the other side.

TelExpress provides a wide array of RF and data connectivity products, including various coaxial cables like LMR-series equivalents, fiber optic cables, and Ethernet solutions. Their inventory supports diverse amateur radio and telecommunications requirements, from antenna feedlines to network infrastructure. The site emphasizes bulk cable availability and custom assembly services, catering to both individual hams and larger installations. Key offerings include _low-loss coax_ for HF and VHF/UHF applications, along with a comprehensive selection of RF connectors. They also supply patch panels, Ethernet cables (Cat5e/Cat6), and general wireless and telecom hardware. Customers can find components for building robust station infrastructure, ensuring signal integrity across various frequency bands. The platform facilitates procurement of essential parts for new builds or upgrades, supporting reliable RF system performance.

Examines Teledyne Cable Solutions' offerings, focusing on their engineered solutions for demanding cable applications. The resource details their capabilities in designing and manufacturing _multi-core cable_ and ruggedized assemblies, emphasizing their integrated approach within Teledyne Marine. It covers the technical aspects of their products, which are tailored to specific operational environments and performance requirements, ensuring reliability in challenging situations. The content highlights the practical application of their cable solutions across various industries, including those requiring robust interconnectivity for remote sensing or communication systems. It implicitly suggests how these specialized cables, designed for high performance and durability, could benefit amateur radio operators seeking reliable feedlines or control cables in extreme weather or portable operations, potentially offering superior signal integrity and mechanical strength compared to standard offerings. The company's focus on custom solutions distinguishes its approach.

HyEnd is a dutch amateur radio antenna manufacturer. Makers of the popular HyEndFeed Antennas, produce Baluns, bandpass filters and selle Line isolators, coax cables and connectors.

From buying an amateur radio transceiver, choosing the correct power supply, selecting the antenna and its feed line, to choosing the best microphone and accessories. A nice presentation for beginners.

This 160 meter Delta Loop antenna is made of Hard drawn copper wire AWG 10, the two upper side are 148.5 foot each base wire is 240.9 foot, the feed point at 30.69 foot to one corner, feed with 450 Homs balanced line to an antenna tuner on the ground, then with 50 homs coax to the shack.

These baluns are used to attenuate the common mode current that flows on the outside of the coaxial feed line.

This is a small collection of K9YC info and my experiences. Problems by feed lines of 1/2 lambda length. CMCs in transmitting and receiving systems. Antenna unbalance, Maximal allowed power, Choke winding tips.

The PAC-12 Antenna, a multi-band portable vertical, is meticulously detailed in this construction article by James Bennett, _KA5DVS_. The design emphasizes ease of homebrewing using readily available components from local hardware stores, including replaceable loading coils. It outlines the preparation of the 72-inch telescoping whip (originally from Radio Shack, with an alternate source now provided by _Pacific Antenna_), the construction of the loading coils from PVC risers, and the fabrication of the aluminum rod base sections. Specific instructions cover threading aluminum rod with a _1/4-20 threading die_ and assembling the feedpoint insulator with a BNC connector, along with recommendations for radial deployment. KA5DVS, an avid traveler and QRP enthusiast, developed the PAC-12 to address the bulkiness of random wire setups and the limitations of commercial portable antennas like the Outbacker or SuperAntennas MP1. His goal was a lightweight, packable antenna that disassembles into 12-inch sections, achieving an assembled length of approximately 8 feet. The design strategically places the loading coil away from the base for improved efficiency. The PAC-12 notably placed first in efficiency compared to a quarter-wavelength wire vertical at the HFPack antenna shootout during the Pacificon conference in October 2001, demonstrating its practical performance for field operations. Appendix C showcases various _NJQRP Club_ members' PAC-12 constructions, including a 20m beam made with multiple PAC-12 elements.

This article details the design and construction of a homebrew two-element loop antenna array for HF reception. The DIY receiving antenna system consists of two 30-inch diamond-shaped loops spaced 20 feet apart, offering superior directivity compared to traditional vertical arrays. The design features broadband operation from 160m to 20m bands, requiring only phase-delay adjustments via feedline lengths. This home-built antenna system achieves 9dB RDF (Receiving Directivity Factor) performance comparable to a 300-foot Beverage antenna, while requiring minimal space and no ground radials, making it ideal for suburban installations and low-band reception.

Explains the fundamental purpose of a repeater, detailing how these automated relay stations overcome distance and terrain limitations for VHF/UHF communications. It traces the historical development from early Bell Telephone Labs "relay" stations in 1922 to Art Gentry, W6MEP's, pioneering K6MYK amateur radio repeater in the mid-1950s, which remains active today. The resource clarifies the distinction between simplex and duplex operation, including the unique function of a "parrot repeater" for single-frequency recording and playback. Delving into the internal workings, the guide breaks down a repeater into its core components: the antenna system, feedline (often _Heliax_ or hardline for minimal loss), duplexer, receiver, transmitter, and controller. It emphasizes the critical role of the duplexer in preventing receiver desensitization by isolating transmit and receive signals, even with distinct frequencies. The discussion highlights the importance of high-performance, durable antennas and low-loss feedlines, citing examples of equipment installed in the 1960s and 1970s that are still in perfect working order. Operating a repeater is also covered, with an explanation of frequency offset (e.g., the 600 kHz standard for 2 meters) and the function of _CTCSS_ (PL tone) for access. It outlines standard input/output offsets for various bands, from 6 meters to 23 centimeters, while noting regional variations. The guide also touches on features like autopatch and Digital Voice Recorders (DVRs), providing a solid foundation for understanding repeater technology and usage.

Extended Double Zepp measurements for all ham bands, and online calculator. The antenna is constructed much like an ordinary Dipole antenna but with 5/8 Wavelength Elements matched with an added Impedance Matching Section of balanced feed line

Undertanding the velocity factor in coax cable feed lines. Meaning of the veolcity factor index related to the RF speed of a signal inside the coax cable.

A unique, easy-to-use Amateur Radio program for creating County, State, Section and Grid Locator outline maps of North America that can be filled by Hand, from a Contest Logger UDP Feed, or from Imported ADIF or Cabrillo Logs.

This page presents an online calculator tool for determining the dimensions of various HF wire antennas operating between 1.8-30 MHz. Users input their desired resonant frequency to obtain precise measurements for four popular antenna types: standard flat-top dipole, inverted Vee, quad loop, and equilateral delta loop. The calculator provides comprehensive measurements including leg lengths, minimum heights, horizontal spreads, and feedpoint distances. Accompanying the calculator are detailed technical explanations, construction notes, and installation guidelines for each antenna type, making it a practical resource for amateur radio operators building their own antennas.

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.

The **Nilex Morse Tutor** is an HTML5 web application designed to teach Morse code reception, adapting to user proficiency by adding new characters as readiness is detected. It prioritizes practice on less familiar letters, numbers, symbols, words, and phrases, while minimizing repetition of already mastered elements. The program offers multiple learning orders, including "Q7ZG..." (Ward/Jim's), "KMRS..." (PU5EPX/Koch), "KMUR..." (lcwo.net), "AENT..." (CWops CW Academy), "TEAN..." (Stephen C Phillips), "ANET..." (Vic VE3YT), and "ETI5..." (Ham Whisperer), alongside an alphabetical option. Users can customize the learning experience by enabling or disabling automatic progression, and selecting specific content categories such as numbers, symbols, words, phrases, QSO bits, Ham Radio Bands, X+Y=Z math, and units. Audio settings are adjustable for volume, speed (WPM), tone frequency, and keyshape/keying envelope, allowing for a personalized auditory environment. The interface provides visual feedback with blue bars indicating practice emphasis and gray bars for reserved characters, with clickable bars for manual character selection. Developed by "Nosey" Nick Waterman, VA3NNW, this tutor is based on earlier versions by Jim Wilson and a 1977 QST article. A significant October 2019 rewrite incorporated a new WebAudio sound library by AwesomeAidenW, improving offline functionality and mobile support. The content library was expanded to include 3000 top Google words, 2284+ General Service List words, ISO country codes, capital cities, US states, Canadian provinces, UK counties, common names, periodic table elements, quotes, Q-codes, electronic components, ham abbreviations, and example call signs. The software is distributed under the GNU GPL V2 license.

The Beverage we use is a DX Engineering RPS-1 dual directional 360 foot 109,7 m, oriented due North/South, six feet 1,8 m off the ground. The antenna uses 450 ohm ladder line as the antenna, and 75 ohm RG-6u for the feedline. The antenna runs atop the fence between our property and 5 acres of pasture next door.

Transmission lines have many uses other than simply transferring RF power from one point to another. Impedance matching, baluns and filters are probable the most common of these.

Helical antenna or helix antenna is the antenna in which the conducting wire is wound in helical shape and connected to the ground plate with a feeder line. It is the simplest antenna, which provides circularly polarized waves.

The Score Distributor facilitates real-time score forwarding for amateur radio contests, automatically transmitting data from various logging software to multiple online scoreboards. By configuring logging applications to send score data to the Distributor, operators ensure their current score is simultaneously represented on platforms like the _Contest Online ScoreBoard_ (COSB) and the Live Contest Score Server by R4WW. This system eliminates the need to choose a single scoreboard, providing broader visibility for participants. This utility enhances the competitive experience by allowing contesters to monitor their performance against other stations throughout an event. Observing real-time standings can provide significant motivation, particularly during periods of challenging propagation or when striving to maintain pace with club members or peers. The platform supports almost all major contest logging software, simplifying integration for a wide range of operators. Developed by WA7BNM, the Score Distributor was last revised on June 14, 2023. It aggregates score data, offering a unified point of submission that then disseminates the information, ensuring a **single point of entry** for broad scoreboard coverage and improving the dynamic feedback loop for participants.