Here’s a side-by-side comparison of horn-antenna dimensions for hydrogen-line (≈1420 MHz, λ ≈ 21 cm) observation from SETI League / astronomy.me.uk recommendations and the academic designs referenced in the Harvard/McMaster…
Short answer first, then the nuance. TL;DR (rule-of-thumb) For 1420 MHz hydrogen-line pyramidal horns: That’s why almost all serious 21 cm horns cluster around 15–25°. What “problems” actually appear —…
Same frequency, physically bigger horn — not frequency scaling.This is where horns stop being “just scaled” and start being designed. Short answer first:You increase the aperture size, but you do…
Short answer: it scales linearly with wavelength.Longer answer (the bit you actually care about 🙂): For a hydrogen-line horn (≈1420 MHz, λ ≈ 21 cm), the flare geometry is set…
Following is result of asking ChatGPT the above question 27/1/2026!!!! Here’s a source that actually describes the original SETI Horn of Plenty antenna design and its dimensions: 🔗 SETI League…
These are both relatively long integration times on the Intel i5 MiniPC used for this experiment. The numbers are not equivalent – in both cases I attempted to obtain an…
Screenshot: Data Collection Videos: Data Files: https://www.astronomy.me.uk/wp-content/uploads/2026/01/LRO-H2_ezColGR260104GR_260123_13.txt https://www.astronomy.me.uk/wp-content/uploads/2026/01/LRO-H2_ezColGR260104GR_260123_14.txt https://www.astronomy.me.uk/wp-content/uploads/2026/01/LRO-H2_ezColGR260104GR_260124_00.txt
Admin