Radio observation in hydrogen line (1420MHz)

Suggested dimensions for a 3 metre H-Line Aperture Horn Antenna

These may be debated by other builders……note I haven’t built this sized horn so cannot demonstrate its effectiveness – rather, this is my attempt to calculate the dimensions needed. https://www.astronomy.me.uk/wp-content/uploads/2026/01/Optimal-dimensions-of-3m-H-Line-Aperture-Horn-Antenna.pdf

Designing my SETI H-Line Horn of Plenty 31/12/2025

From SETI League on building Horn of Plenty: https://www.astronomy.me.uk/wp-content/uploads/2026/01/10629-scaled.jpg https://www.astronomy.me.uk/wp-content/uploads/2026/01/Building-SETI-Horn-of-Plenty2003.docx SETI League Feedhorn Excel Spreadsheet Calculator: https://www.astronomy.me.uk/wp-content/uploads/2026/01/SETI-League-Feedhorn-Analysis-Excel-Calulator.xls Design for my own Horn of Plenty using diagrams and photos from SETI…