HF Multiband Moxon Antenna
A DIY guide to building a compact, single-feed triband Moxon wire beam for 20, 15, and 10 meters.
Description
Constructing a compact, single-feed triband Moxon antenna for 20, 15, and 10 meters is detailed by DU1RZ, drawing from his personal experience with space-constrained antenna projects. Initially fascinated by cubical quads, the author transitioned to Moxon designs in 2005 after realizing his roof space was insufficient for a bulky quad. His first experimental monoband Moxon for 15 meters, built from repurposed materials, provided solid DX QSOs for seven years, despite being slightly below the 21 MHz band center.
The project outlines the design process, including using the MOXGEN Calculator for element dimensions and material selection, such as #14 AWG enamel copper wire and fishing poles for spreaders. DU1RZ shares insights from simulations with DL2GMS regarding insulated versus non-insulated wire performance, noting that insulated wire can shift resonant frequencies lower. The assembly instructions cover preparing wire elements, connecting feed points, and tuning the antenna, with initial SWR measurements taken at 10 feet and final readings on a mast showing excellent results: 1.0:1 on 14.225 MHz, 1.1:1 on 21.250 MHz, and 1.3:1 on 28.50 MHz. Transmission tests with 4F1BYN indicated a front-to-back ratio of approximately 2 S units with 10 watts output.
The author emphasizes adaptability, encouraging builders to use readily available materials rather than strictly replicating his setup. Key observations from DU1RZ and DL2GMS highlight the antenna's strong performance across 20, 15, and 10 meters, good front-to-back ratio, full bandwidth on 20 and 15 meters, and its small turning radius of about 4.18 meters (13.54 feet), making it suitable for limited antenna space. Its lightweight construction and low wind load are also noted as significant advantages.