Hardware

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)

What is maximum flare angles of hydrogen line horn antennas before the antenna develops problems?

Admin February 1, 2026 No Comments

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 —…

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)

Scaling the SETI Horn of Plenty (Hydrogen Line Horn Antenna)

Admin January 31, 2026 No Comments

Hi Andy, You recently asked a question on the SARA forum “I notice that the SETI Horn of Plenty is a smaller version of the original Ewen Horn that first…

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)

If I want to make a bigger version of the SETI Horn of Plenty, still for 1420 MHz, how do I increase the dimensions?

Admin January 27, 2026 No Comments

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…

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)

How does flared section of hydrogen line horn antenna scale with changes in wavelength measured?

Admin January 27, 2026 No Comments

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…

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)

Find me an URL for original SETI Horn of Plenty dimensions

Admin January 27, 2026 No Comments

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…

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna) Waveguides

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.

Admin January 19, 2026 No Comments

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…

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna) Waveguides

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

Admin January 19, 2026 No Comments

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…

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)

Plan and measurements of proposed LRO Hydrogen Line Horn Antenna 14/1/2026

Admin January 14, 2026 No Comments

https://www.astronomy.me.uk/wp-content/uploads/2026/01/Plan-Measurements-for-LRO-Horn-of-Plenty-140126.pdf

Radio observation in hydrogen line (1420MHz) SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)

If I want to make full scale Ewan hydrogen horn what dimensions should I use for all pieces of wood that form struts?

Admin January 14, 2026 No Comments

A full-scale Ewen (often spelled Ewan) hydrogen horn is a big structure, and most of the confusion comes from the fact that the horn geometry is well defined, but the…

Attending & talking at conferences, workshops & societies NanoVNA Radio observation in hydrogen line (1420MHz)

NanoVNA Mini-far-field antenna range from EuCARA Sept 2025

Admin January 13, 2026 No Comments

In September 2025, Jason Burnfield & myself delivered a workshop on creating and using a mini-far-field antenna testing range at home using a NanoVNA. Materials describing how this is done…

What is maximum flare angles of hydrogen line horn antennas before the antenna develops problems?

Scaling the SETI Horn of Plenty (Hydrogen Line Horn Antenna)

If I want to make a bigger version of the SETI Horn of Plenty, still for 1420 MHz, how do I increase the dimensions?

How does flared section of hydrogen line horn antenna scale with changes in wavelength measured?

Find me an URL for original SETI Horn of Plenty dimensions

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.

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

Plan and measurements of proposed LRO Hydrogen Line Horn Antenna 14/1/2026

If I want to make full scale Ewan hydrogen horn what dimensions should I use for all pieces of wood that form struts?

NanoVNA Mini-far-field antenna range from EuCARA Sept 2025

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