Hardware

Show field patterns at 1420 MHz, derive wave impedance vs frequency, explain why feed probes behave oddly near cutoff, and compare WR-650 vs WR-770 specifically for H-line work.

Excellent — I’ll go through all four, keeping it practical and tied to 1420.405 MHz H-line work with WR-650. 1. Field patterns in WR-650 at 1420 MHz For the dominant…

Why do some websites describe WR-650 waveguides as being for frequencies higher than 1420 MHz? Give equations in ASCII format.

Short answer: because different people are talking about different operating regions of the same waveguide, and some descriptions quietly assume single-mode, low-loss, well-matched operation rather than mere propagation. Here’s the…

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…