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Comment by bloopernova | Hacker News Reader

When I have the time, I'd like to build an antenna to try to pick up the hydrogen line from space.

Just that simple thing is so strange to me, that with a handful of components you can listen to the cosmos. I really wish science classes would have included that sort of thing.

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You're in luck! David Schneider, the author of this piece, also built a $150 hydrogen line antenna for us, based on a TV tuner SDR:

https://spectrum.ieee.org/track-the-movement-of-the-milky-wa...

Unfortunately I'm in the middle of moving, but once I'm done with that, I'll give this a try :)

FYI, an antenna for the 21 cm line can be extremely low effort:

https://spaceaustralia.com/news/diy-radio-telescope-sees-fir...

Unfortunately I'm in the middle of moving, but once I'm done with that, I'll give this a try :)

> that with a handful of components you can listen to the cosmos

Tuning an analog radio or TV between stations also accomplishes this in a more abstract way.

Could tuning several analog radio receivers between station be used in some sort of synthetic aperture telescope?

Sounds a bit like Lofar. Stick a few hundred antennas into a field, collect all the raw data, and then do some herculean signal processing and you end up with a fantastic radio telescope that you can "point" retrospectively, e.g. to look at something that just happened in the gamma, before it happened (on a scale of seconds).

https://www.astron.nl/telescopes/lofar/

yes, but in an inefficient way, similar to how large clusters with ECC are weak cosmic ray detectors.

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