Material choice affects an antenna’s efficiency, bandwidth, durability, and mechanical practicality. Here’s a concise breakdown of what really matters: 1. Electrical Conductivity This is the biggest factor. High-conductivity metals (copper,…
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…
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…
Pulsars don’t have a single “pulsar frequency” the way spectral lines do — instead they emit broadband radio noise with periodic pulses, and what we observe are: Here are the…
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…
There are quite a few different Nooelec RTL-SDR dongle versions, and the differences mostly come down to tuner chip, frequency range, stability / oscillator, size, and extra features like bias-tee.…
Extract from SARA Mailing List 20-21/11/2025. https://www.astronomy.me.uk/wp-content/uploads/2025/11/Can-orthogonal-dual-monopoles-reduce-cantenna-signal-strength-Measuring-cross-polarisation-SARA-Mailing-List-20-211125.docx https://www.astronomy.me.uk/wp-content/uploads/2025/11/Can-orthogonal-dual-monopoles-reduce-cantenna-signal-strength-Measuring-cross-polarisation-SARA-Mailing-List-20-211125.pdf MESSAGES BELOW IN REVERSE CHRONOLOGICAL ORDER: From: ‘b alex pettit jr’ via Society of Amateur Radio Astronomers <sara-list@googlegroups.com>Sent: 21 November 2025 22:38.…
Radio-SkyPipe II (R-SP) uses a binary proprietary file format for its data files. Here’s a breakdown of the format, based on the Radio-Sky documentation: File Format (Radio-SkyPipe II) Interpretation /…
In an SDR, three related but distinct concepts often get mixed together: frequency, bandwidth, and sample rate. Here’s how they actually fit together: 1. Frequency (centre frequency) This is simply…
Admin