W2du Hf, 25" Each W2DU balun is built in a weatherized, rugged package with stainless steel hardware and SO-239 UHF connectors mounted on both ends. Find many great new & used options and get the best deals for New (old stock) MAXI-BALUN W2DU-HF 1. Applications for In-line baluns include line isolation anywhere along the coax transmission system and use on Quad and Yagi antennas. Learn about RF chokes and their role in ham radio antenna systems. (Editor note: this type also has the highest losses) 5. The ferrite beads most com-monly used in the HF range (80 through 10 meters) are the Amidon FB-73-2401 or equivalent. This was a perfect opportu-nity for me to build a W2DU Balun: One of the baluns that we discussed last month was the very effective W2DU current balun. Unadilla also sells "W2AU" baluns that IIRC are the conventional transformer type of blauns. The W2DU type is a current type balun with no ferrite cores to saturate. It is an in-line device, meaning it can be easily connected directly to your antenna line, making installation a breeze. vxf1l, 5p, s4rp, 4ng3, vsmnb, ez, kz, z00, pv33, uvklvje,