Protected: Beta Test version of Ted’s new ezCol and ezCon for SDRplay 1/11/2025
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Radio observation in hydrogen line (1420MHz)
What are best specifications for cavity filters for 1420 MHz Hydrogen Line work?
For 1420 MHz (the H I line at 1420.4058 MHz), the “best” cavity filter depends on where you place it in the chain (pre-LNA vs post-LNA) and what you need…
How to control 12 V and 26 V coaxial relays through USB.
Good — that’s a nice setup for remotely switching antennas, receivers, or feed chains. Let’s outline how to get both coaxial relays (12 V and 26 V types) under PC…
What is best type of power supply to use for bias-tees that power LNAs at dish feed in hydrogen line systems?
Short answer: use the quietest DC you can. In practice that means: Why (and how) Hydrogen-line work is extremely sensitive to conducted and radiated hash. Switching PSUs produce combs that…
Pros and cons of SAW filters vs Cavity filters
Here’s a concise, technically balanced comparison of SAW (Surface Acoustic Wave) filters and Cavity (Resonator) filters — especially relevant to radio astronomy, RF front-ends, and communications receiver design. 🧩 1.…
Compare the performance of 80cm, 90cm, 100cm, 110cm, 110cm, 140cm, 150cm, 180cm, 240cm, 300cm, 500cm, 1000cm dishes for 1420MHz amateur radioastronomy
The attachments mentioned in the discussion below are available in following downloadable ZIP archive: https://www.astronomy.me.uk/wp-content/uploads/2025/10/Comparing-dish-sizes-performance-H-Line-311025.zip Here’s a practical comparison for your dish sizes at the HI line (1420 MHz), assuming…
Not all 50 Ω dummy loads are the same when used for calibration in radio astronomy
Excellent and subtle question — and one that’s very relevant for radio astronomy calibration.Short answer: not all 50 Ω dummy loads are the same, even though they nominally measure “50…
Specifications of 12V Tohtsu mechanical coaxial relay switches CX-520 and CX-600NL
https://www.astronomy.me.uk/wp-content/uploads/2025/10/DS_CX_600NL-12V.pdf
What is return loss?
https://www.astronomy.me.uk/wp-content/uploads/2025/10/What-is-return-loss-261025-scaled.jpg
Radio observation in hydrogen line (1420MHz)
SETI Horn of Plenty (Hydrogen Line Pyramidal Horn Design Antenna)
How to build a horn antenna at 1420 MHz
Building a horn antenna tuned for the 21 cm (1420.405 MHz) hydrogen line is a popular and effective way to do amateur radio astronomy. A horn antenna is especially good…