How much of 1420 MHz band is protected in UK?
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In the United Kingdom, the L-band around the 1420 MHz hydrogen line is formally recognised and protected for passive scientific use, meaning emissions by other services are prohibited or very…
Radio observation in hydrogen line (1420MHz)
Can a radio telescope parabolic mirror be made with number hexagons not electrically connected?
Yes — a radio telescope reflector can be made from separate hexagonal panels that are not electrically bonded together, provided certain conditions are met. This is actually very common in…
How to make a simple cavity filter for 1420MHz
Designing a simple cavity filter for 1420 MHz (the neutral hydrogen line at 1420.405 MHz) is very practical for radio astronomy front ends, especially to reduce out-of-band interference before amplification.…
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.…
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…
What is difference between balanced and unbalanced on microphone input?
This is one of those things that sounds boring until it suddenly explains all your noise problems. Alright — let’s break it down in human terms. 🎙️ Unbalanced microphone input…
How does a modern software defined radio attain an less erratic noise floor than older amateur radio sets?
The answer isn’t “magic DSP.” It’s architecture. And a bit of ruthless engineering discipline. Modern SDRs don’t actually have “less noise” in the physics sense — they have more stable,…
What is a Pin Diode?
Absolute workhorse of RF switching. WHAT IS A PIN DIODE? A PIN diode is a semiconductor diode with three layers: The middle layer is a thick, undoped (intrinsic) region. That…
What is a Dicke switch in radio astronomy?
WHAT IS A DICKE SWITCH? A Dicke switch is a rapid RF switch used in radio astronomy to reduce receiver gain drift. It switches quickly between: This technique was invented…