80 40 30 Trapped Delta Loop Antenna Project

This project details the construction of a tri-band trapped delta loop antenna designed for operation on 80 meters (3.5–4 MHz), 40 meters (7–7.3 MHz), and 30 meters (10.1–10.15 MHz). The design utilizes a single triangular wire loop with a coaxial feedline, eliminating the need for an external tuner or band-switching relays. The methodology involves specific trap placement within the horizontal element to achieve resonance on 40M and 30M, while the overall physical perimeter of approximately 270 feet establishes 80M as the fundamental band. The document specifies slant leg lengths of approximately 80 feet each. Trap design and placement are described, with 30M traps positioned inboard of 40M traps. The resource references ARRL Antenna Handbook and ON4UN’s Low Band DXing for foundational information on full-wave loop behavior and feedpoint impedances. The antenna aims to provide multi-band operation from a single structure.