British Astronomical Association Hydrogen Line Sub-group meeting 1/12/2025
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https://files.ad.thornett.net/astronet/BAA_H-Line_Meeting_011225.mp4
Radio observation in hydrogen line (1420MHz)
How does amplification on Nooelec SAWBird H1 vary with voltage on power supply input?
Short answer: the SAWbird H1’s gain is essentially fixed by its RF amplifier bias network and SAW filter — within the manufacturer’s recommended supply window (≈3.3–5.5 V) you should see…
Comparing RTL-SDR v3 and v4 software defined radios
Here’s what’s inside — i.e. the chips used: In short: R820T2 tuner + RTL2832U demodulator/ADC. Since you’re already familiar with SDR and radio-astronomy, here’s a summary of the key components…
What does following product do? RFandEMF TM-195: 3 Axis High Frequency/RF Measurement, EMF Meter covers 50MHz – 3.5GHz
Here’s what does — and when/how you might use it: ✅ What the device does 🔎 Typical Uses / Why People Use It This kind of RF/EMF meter is commonly…
Dave Bracey’s Hydrogen Line 3D modelling of Milky Way arms
From Dave’s brilliant data set suppled 27/11/2025 – (c) Dave Bracey 2025 – all rights reserved. Taken using Dave’s 150cm homemade backyard radio telescope in Bromyard, England, UK, 2025.
How does the radio frequency SAW filter in a Nooelec SAWBird LNA and filter?
In the SAWBird line of LNAs (e.g., for 1420 MHz, GPS, L-band), the SAW filter is the component that provides the ultra-narrow preselection that makes these modules so effective for…
What is spillover vs ground reflection in radio astronomy?
In a radio telescope’s noise budget, spillover and ground reflection are two distinct ways unwanted radiation enters your receiver. They’re related but not the same: Spillover Spillover is receiver noise…
Is it benefitial to ensure that low noise amplifier and filter (LNA) for hydrogen line observing is at a constant temperature?
Andrew Thornett: I could see potential benefit for having LNA at constant temperature. The easiest way to achieve that is to cool it below any likely outside temperature – avoiding…
What is most expensive low noise amplifier and/or filter available for hydrogen line radio astronomy?
Short answer: the most expensive single-component front-end parts used for 1.420 GHz (H-line) work are cryogenic HEMT/InP LNAs and the associated cryogenic front-end systems (LNA + cryostat + cryocooler). Top…
Description of SAWBird H1+ LNA from Nooelec’s own website 23/11/2025
This might be of interest to folks interested in amateur hydrogen line radio astronomy – it is the description of the SAWBird H1 directly from Nooelec’s website today 23/11/2025: https://www.nooelec.com/store/sawbird-h1.html…