This is a great recommendation, thanks! I've found a lot of interesting old radio hobbyist magazines on the Archive, whose copyright has expired. While it's great to see how people could get stuff done with the very limited electrical resources available in the 01910s and 01920s, many of the designs depend on materials that are now hard to find, while materials that are now easy to find (like PN2222s) didn't exist.

We have a big and ongoing focus on amateur radio right now thanks to a grant from ARDC and really hard work by our awesome Program Manager Kay Savetz. Worth checking out: https://blog.archive.org/2022/11/16/digital-library-of-amate... https://archive.org/details/dlarc

Thanks! I had no idea! Your work is one of the three or four most important projects sustaining civilization right now; it will be profoundly missed when it's gone.