In 2008 I published a series of articles in the SARA journal about the
observation of the hydrogen emission with simple means. These articles
are available on our website. Every now and then I have referred people
to it. Among these was Alex who suggested to point the audience here to
the series.
Following this suggestion, here is the link for anyone who might be
interested:
https://www.astropeiler.de/en/beobachtungen-der-21-cm-linie-mit-einfachen-mitteln/
Having said that, as these articles are five years old some advances in
available equipment are worth noting: On the LNA/filter topic, now the
devices from Noolec became available which combine convienently LNA
with a suitable filter. Since then, we have also used the Airspy and
SDRplay RSP2pro successfully for hydrogen observations. Probably the
biggest advances have been made on the software side. Meanwhile many
packages have become available which were not mentioned in the article.
I hope I can write an article about the various software packages in
the future which then would be complementing what has been published
back in 2008.
Best regards,
Wolfgang