Is the speed of light a real speed?
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Yes — the speed of light is a real, physically measurable speed. The quantity usually denoted c is the speed at which electromagnetic waves propagate through a vacuum. Its defined…
2026
Product Review: Mini Circuits ZVBP-1420-N+ Cavity Band Pass Filter, 1415 – 1425 MHz.
Compared to the GPIO filters discussed in another article in this issue, Mini-Circuits’ 1415-1425 MHz cavity filters are at a significantly higher price point (around $700 at the time of…
The current range of 1420 MHz Hydrogen Line Filters and Low Noise Amplifiers supplied by GPIO.
Dr Andrew ThornettLichfield Radio Observatory – www.astronomy.me.uk GPIO Labs produces a selection of filters and low-noise amplifiers designed specifically for observations of the neutral hydrogen spectral line at 1420 MHz.…
Setting up LRO 134cm VLF Aerial with direct input into USB Sound Card (except for 10 uF capacitor on one arm of input) on LRO-PC-10 mini-PC with Spectrum Lab software for continuous monitoring starting 21/2/26@18:00 UTC
Working configuration file on Spectrum Lab Software: https://www.astronomy.me.uk/wp-content/uploads/2026/02/LRO_VLF_Config_works-with-134cm-aerial-LRO-PC-10-210226@1800.zip Plot from Spectrum Lab showing the 5 stations being monitored & photo of the 134cm VLF aerial:
First Light LRO 134cm VLF Aerial with Direct Sound Card Audio Input (10 uF capacitor on one arm) 20-21/2/2026
I am grateful to the help of John Berman on this project – I based the arrangement at LRO on his design. It uses Spectrum Lab Spectrum Analyser software, and…
I am making VLF aerial out of 22 SWG enamelled copper wire about 150m long, wound around a wooden cross multiple times. How important is exactly length of the wire?
For a VLF receiving loop, the exact wire length is usually far less critical than people expect. At VLF (about 3–30 kHz): So you are not building a resonant half-wave…
Success using direct USB audio soundcard input from VLF aerial (with serial 10 uF capacitor) at LRO 20/2/2026 @ 21:20 UTC
Success with detection! Bits and pieces arrived to make new aerial – and attached are test screenshots from Spectrum Lab – 6 stations seen clearly. This time, for some reason,…
Can Hammerite Paint be used in paint sprayer on Radio astronomy dishes?
Note this post doesn’t look any question about whether the paint affects signal reception. It only addresses whether the paint will work with a paint sprayer. **Hammerite** paint can be…
Where did name Soapy come from in Soapy drivers, such as available in GNU Radio?
The name “Soapy” in SoapySDR (and the associated Soapy drivers) comes from the idea of making SDR hardware support clean and simple — as in “soap makes things clean.” SoapySDR…
How big is the area of a cosmic ray burst is at ground level?
This question is relevant to considering how close two observers need to be to each other in order to observe the same muon cascades, and hence obtain similar muon detections/have…