Foil-lined foam insulation board, scraps of lumber, and a paint-thinner can ... antenna is then piped into an inexpensive low-noise amplifier (LNA) specifically designed for the hydrogen line ...

If I ask you to picture a radio telescope, you probably imagine a large dish pointing to the sky, or even an array of dish ...

That’s the electromagnetic spectral line of hydrogen ... a reasonable 21-cm rig can be had for about $200 or so, less the antenna. He promises a follow-up paper on homebrew 21-cm antennas ...

A 19.8 kW PV system is powering a telecommunications antenna at a French air control center. When it produces more energy than needed, the surplus is used to produce hydrogen which is then ...