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Show diagrams, winding methods and tables of some 1:1 and 4:1 baluns for 1.8 - 30 MHz suitable for use up to 200W (400W peak) on systems using 50 or 75 ohm coaxial cable input where SWR should not exceed 1.6:1.

The Windom is an Off-center wire multiband Antenna. The old version was fed just by a single-wire connected on 1/3 of antenna's overall length or with an open-line feeder (later versions). Here is another model with coaxial feeder, which is compatible with Solid States - 50 Ohm output transceivers .

Online calculator for a 4 to 1 coax cable balun

Classical coax-fed, off-center-fed dipole, feeded with a 4:1 Guanella balun

Presents the construction of a shortened _Morgain_ dual-band wire antenna for 40 and 80 meters, specifically designed for installations with limited physical space. The design achieves a compact footprint of approximately 10 x 0.5 meters, utilizing 64 meters of 1.5 mm² insulated electrical wire. The article details an alternative configuration that reduces the antenna's physical length while maintaining its electrical characteristics for dual-band operation. Author _Remo - IM0JZJ_ conducted tests from Sant'Antioco, Sardinia, reporting SWR measurements of 1.2:1 to 1.4:1 on 40 meters. On 80 meters, SWR ranged from 1.1:1 to 1.5:1 across 3620 kHz to 3720 kHz, with a 1:1 current balun recommended for coaxial feed due to the antenna's approximately 50-ohm feed-point impedance. The installation used two 11.50-meter galvanized steel poles, supporting the antenna at about 10 meters above ground. Construction involves three wooden boards and sixteen fiberglass laminate spacers, with specific instructions for routing the 32-meter wire arms. The design eliminates jumpers for 40-meter tuning but requires two jumpers approximately 1.45 meters from the ends for 80-meter operation, which are tuned and then permanently soldered.

This blog post details the construction and usage of a 4:1 current balun, using two FT240-31 ferrite cores and 12 bifilar turns. It clarifies common misconceptions about using 4:1 baluns with G5RV antennas and ladder-line to coaxial cable connections. M0PZT emphasizes the importance of proper measurements and the limitations of internal baluns in manual antenna tuners. Detailed instructions and considerations for winding and deploying the balun are provided, along with advice on choosing suitable cores and wire for various power levels and frequency ranges.

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.

VE2AZX's 2013 Radio Talk presentation details the technical aspects of baluns, including reasons for their use, various types, and methods for performance verification using an SWR analyzer. The document specifically examines 1:1 voltage baluns and 4:1 voltage baluns, outlining their winding configurations and typical impedance transformations. It presents empirical SWR measurements for W2AU 1:1 baluns and Unadilla 4:1 baluns, tested with both 50-ohm and 200-ohm resistive loads across the HF spectrum. The presentation further explores the measurement of ferrite impedance and their application in mitigating common-mode currents on feeders and household conductors. Key concepts addressed include balanced-to-unbalanced transformation, ensuring feeder independence from the antenna, and reducing unwanted feeder radiation. The content emphasizes practical testing procedures to ensure optimal antenna system performance and minimize RF interference. Discussions also cover open-circuit tests with SWR analyzers and VNAs to assess winding inductance, distributed capacitance, and insulation quality. The presentation differentiates between voltage and current baluns, explaining how current baluns, particularly those utilizing ferrite cores, reduce outer shield currents without affecting internal coaxial cable currents, thereby preserving the antenna's intended radiation pattern.