Short answer: you can make a cavity “as big as you like,” but past a sensible size you don’t gain performance—and you often make things worse (more spurious modes, weight,…
Adding more digits (fingers or resonators) in an interdigital RF cavity filter has several important advantages and disadvantages, depending on what you are optimizing for (selectivity, insertion loss, bandwidth, physical…
Short version: “Parallel” doesn’t help—and can make things worse. Here are the three ways people mean “parallel,” and what actually happens: If your goal is to move the −3 dB…
Short answer: not really. Mini-Circuits “DC–22 MHz” parts are fixed, 50 Ω-matched, sealed networks (usually elliptic/Chebyshev LC). To move the cutoff up by ~2 MHz you’d need to reduce the…
There is no excerpt because this is a protected post.
Pictures can be accessed via download of ZIP archive below: https://www.astronomy.me.uk/wp-content/uploads/2025/11/Pictures-for-Astronomy-Now-011125.zip
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…
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…
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…
Admin