Answer by Jason Burnfield: On Tue, May 26, 2026 at 1:33 AM Andrew Thornett wrote: Can I ask you for your back of envelope dB calculation on the trace from my…
For a WR-650 waveguide at the 1420 MHz hydrogen line, the internal dimensions need to be about 165 mm × 82.5 mm (6.5″ × 3.25″). That means you’re looking for…
Yes, a pyramidal horn antenna can generally be made larger by adding an additional flared section to the front, but there are some important caveats. A horn antenna works by…
Engineering-style comparison of the two—useful if you’re deciding for SDR work like interferometry or radio astronomy. Compared devices Key specifications comparison Feature Frequency range 24–1700 MHz native 24–1800 MHz (similar…
One upgrade that often improves hydrogen-line observations more than adding extra amplifiers or filters is improving the frequency stability of the SDR. Use a stable reference (TCXO or external clock)…
There **are numerous online references linking AirSpy software-defined radios (SDRs) with software-defined radio use in radio astronomy, both in project guides and community discussions about detecting astronomical signals. Here are…
https://www.astronomy.me.uk/wp-content/uploads/2026/02/Calculating-pyramidal-horn-gain-different-apertures-080226.pdf
On Monday, 26 January 2026 at 08:32:18 GMT, andrew.thornett via Society of Amateur Radio Astronomers <sara-list@googlegroups.com> wrote: I notice that the SETI Horn of Plenty is a smaller version of…
Link below to URL of webpage with such a calculator: https://www.everythingrf.com/rf-calculators/pyramidal-horn-antenna-gain-calculator
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…
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