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The "Largest YU Moxon" document details the design and construction of a substantial multiband Moxon antenna, primarily for 80m, 40m, and 20m operation. It presents specific design parameters derived from NEC-based simulations, including a 4-element 80m Moxon with 37 dB F/B and 7.81 dBi gain on a 47m boom, a 4-element 40m Moxon with a bidirectional pattern, and a 6-element 20m Moxon optimized for specific side lobes. The resource provides precise element lengths and spacing in meters for each band, alongside measured SWR results across the 3.650-3.800 MHz, 7.000-7.100 MHz, and 14.000-14.350 MHz segments. The construction narrative outlines the challenges and solutions encountered by the YU team, including the use of trees for support, the creation of "ugly" air-choke baluns from RG-58 cable wound on plastic bottles for each band, and the meticulous process of attaching wires to a rope boom. It documents the physical dimensions of the vineyard site (47 x 38m) and the azimuth orientation (340 degrees) chosen for the antenna. The document is distinctively useful for its practical insights into large-scale antenna deployment in a field environment, offering real-world SWR measurements and anecdotal performance reports from CQWW contest operations. It includes numerous photographs illustrating the construction process, the team members, and the finished antenna structure, providing visual context to the technical details.

The document details the optimization and construction of the _Maria Maluca_ antenna, a compact 6-band (20m-6m) directional beam. It presents a comparative analysis of shortwave antenna principles, highlighting the efficiency gains achieved by using an open feeder line and tuner as a resonant unit, contrasting this with the losses associated with traps or capacitive loads in multiband antennas. The resource specifically revisits an older South American 2-element design for 10, 15, and 20 meters, applying modern NEC-based software to develop a six-band version. Performance data is meticulously tabulated, showing impedance, free space gain, gain at 12m height, elevation angle, and front-to-back (F/B) ratio for each band from 20m through 6m. For instance, on 15m, the antenna achieves 5.1 dBd free space gain and 13.72 dB F/B ratio. The construction section provides practical guidance on element assembly using aluminum pipes and hose clamps, detailing the use of a heavy-duty glass fiber reinforced polyamide rod for electrical separation and bending strength. It also specifies the use of 450-ohm _Wireman_ line CQ 552 for the transmission line. The document includes diagrams for rod fixing, an air-wound balun, and a vertical elevation diagram for the 15m band, illustrating its DX qualification. It also discusses the antenna's suitability for portable and expedition operations, noting its compact transport dimensions (max 1.50m length, 12 lb weight) and quick assembly time (under 15 minutes). The author, Dipl.Ing. Helmut Oeller, DC6NY, is identified as a source for material kits.

40mm diameter grey PVC pipe with a length of 9.5cm

An air-wound balun made with coaxial cable can not become saturated because no powder iron or ferrite core is present. In this article author explains and compare coax baluns to ferrite baluns with comparison tables and detailed pictures

A home made end-fed half-wave antenna coupler with antenna lenght calculator and counterpoise calculator based on center frequency. Includes pictures and drawings along to antenna homebrewing instructions with a home made on air wound transformer

Constructing a 4:1 Guanella current balun involves cross-connecting two 1:1 current baluns. At the low-impedance end, transmission lines from each balun are connected in parallel, while at the high-impedance end, they are connected in series. This configuration allows the device to achieve a 1:4 impedance ratio, effectively transforming a 200-ohm load to 50 ohms. The balun described utilizes **FT240-43 toroids** wound with 2.5mm2 twisted pair cable for 8 turns, intended for use with a 20m **Deltaloop antenna**. Measurements performed with a 200-ohm resistor demonstrate satisfactory VSWR and impedance characteristics across the HF bands. The article compares the performance of 2.5mm2 cable versus 1mm enameled wire, recommending the former for superior efficiency. Emphasis is placed on maintaining short core-terminal connections to optimize performance. Additional considerations include the option of integrating a separate Common Mode Choke (CMC) for enhanced common mode current suppression, especially if the balun's inherent suppression is not prioritized.