80 40 30 Trapped Delta Loop Antenna Project

The tri-band trapped delta loop antenna design operates on 80 meters (3.5–4 MHz), 40 meters (7–7.3 MHz), and 30 meters (10.1–10.15 MHz) using a single triangular wire loop. This configuration eliminates the need for an external antenna tuner or band-switching relays. The antenna's physical perimeter, approximately 270 feet, establishes 80M as the fundamental band, with specific trap placements enabling resonance on 40M and 30M.

Trap design and placement are critical, with 30M traps positioned inboard of 40M traps within the horizontal element. Each slant leg measures approximately 80 feet. The resource references foundational information from the ARRL Antenna Handbook and ON4UN’s Low Band DXing regarding full-wave loop behavior and feedpoint impedances. The project aims to provide multi-band HF operation from a single, fixed antenna structure.