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The Linked Dipole is a multiband antenna designed for 80/60/40/30/20m bands, optimized for the (tr)uSDX low bands configuration. It incorporates a 1:1 Balun to prevent common mode currents, ensuring balanced operation with coaxial cable. The Balun, wound on an FT140-43 core, achieves 37-40dB attenuation. The design includes a 3D-printable housing for compactness and waterproofing, with labeled link insulators for ease of use. Wire lengths were meticulously adjusted for optimal performance with a 7m pole and 3m rope extension, ensuring the antenna's ends are off the ground for improved behavior. The project includes downloadable printables for DIY construction.

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.

Here is a formula and calculator for creating a loaded (shortened) quarter wave vertical or balanced dipole. The calculation refers to either a loaded 1/4 wave or a loaded dipole

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

In the quest for an ideal field portable antenna, the author recounts experiments involving various wire configurations. While a previous candidate, a 41ft random wire, proved effective but lacked stealth, the search led to a surprising rediscovery of a design previously rejected—the Rybakov Antenna. With a focus on simplicity, rapid deployment, and multiband capability, the author explores the versatility of a 26ft Rybakov, avoiding the halfwave trap. The article delves into the antenna's performance and its potential as a discreet, resonant solution for field operations, addressing the challenges encountered during a POTA activation. Additionally, the Unun/Balun design used in conjunction with the Rybakov Antenna is discussed, providing insights into achieving a balanced system.

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 article clarifies the roles of baluns, ununs, common mode chokes, line isolators, and impedance transformers in amateur radio. A balun decouples balanced antennas from unbalanced feed lines, preventing interference. Ununs serve a similar purpose for asymmetrical antennas. Common mode chokes and line isolators suppress common mode currents, reducing noise. Impedance transformers adjust antenna impedance to match feed lines but do not decouple or suppress common mode currents. Understanding these components is crucial for optimizing antenna performance and minimizing interference.

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.

This comprehensive three-part guide examines baluns (balanced-to-unbalanced devices) and their critical role in ham radio antenna systems. The author explains how baluns prevent common-mode currents on feedlines, which can distort radiation patterns and cause unwanted RF in the shack. Various balun types are analyzed, including coiled coax chokes, ferrite-core designs (W2DU), and toroidal-wound versions (Guanella/Ruthroff). Construction techniques for 1:1, 4:1, 6:1, and 9:1 current baluns are provided with practical guidance on wire selection, winding methods, and ferrite core properties. The article emphasizes that proper balun implementation is essential for optimal antenna performance, especially with directional arrays.

The PA0FRI Unbalanced/Balanced ATU is a home-built antenna tuner designed to efficiently match a W8JK 2-element beam antenna fed with a 450-ohm twin lead. Based on PA0FRI’s S-Match design, it optimizes energy transfer while maintaining balance, reducing losses, and ensuring proper radiation. The tuner uses a roller inductor, air variable capacitors, and a T200 iron powder coil, allowing fine-tuning across 14-50 MHz. Extensive lab tests confirm minimal attenuation and precise impedance matching, making it a reliable and efficient ATU for balanced antennas.

Learn how to construct a balanced Antenna Tuning Unit (ATU) for your ham radio equipment. Follow the instructions provided by Bengt, SM6APQ, to create a variable capacitor insulated from the ground for additional safety. Discover how to set up the ATU for the 20 to 10m band with proper spacing between coils. Use low power when adjusting the ATU for lowest SWR. Avoid using switches and opt for banana plugs for flexible connections. Visit the Creative Science Centre website for more information and resources on ATU construction.

This article describes an HF upconverter for the FunCube Dongle Pro. Designed for radio amateurs, the converter extends reception capabilities to lower frequencies (0 Hz to 30 MHz) by mixing them with a higher oscillator frequency (100 MHz). This translates the desired signal into a range detectable by the FunCube Dongle (64 to 1,700 MHz). Key components include a double-balanced mixer and a low-pass filter to suppress unwanted signals. The project provides schematics, filter specifications, and design considerations for construction.

A dual insert microphone design for the Icom IC-7300 transceiver utilizes a **Besson BZ2400 M4 Rocking Armature** insert for frequencies from 500 Hz to 3 kHz, exhibiting a rising response of approximately 11 dB. A generic Electret Condenser insert, powered by the transceiver's microphone line, covers the low-frequency range from 100 Hz to 500 Hz. A Low Pass Filter is incorporated after the Electret insert to prevent frequency overlap, and a pre-set potentiometer (VR1) adjusts the low-frequency response, balancing the output of both inserts. The design emphasizes a "Close Talking" arrangement and addresses audio "colorization" by housing the Besson insert in a thick rubber holder with a foam boot, separate from the circuitry, with the Electret insert also wrapped in a foam boot. Critical importance is placed on using the correct BZ2400 M4 insert with 12 holes in its face plate. The frequency response table for the BZ2400 M4 insert shows 0 dB at 500 Hz, rising to +11 dB at 3000 Hz, while the Electret insert with the Low Pass Filter provides 0 dB at 100 Hz, rolling off to -9 dB at 500 Hz and -50 dB at 3000 Hz. This combination ensures a broad, balanced audio spectrum for SSB operation. The project includes a circuit diagram, a comprehensive parts list detailing components like a 1 Henry iron-cored inductor (L1) and various capacitors, and a board layout within the metal tube. The completed unit provides a tailored audio profile for the IC-7300, enhancing transmit audio quality.