In the 1920's the popular technical magazines (and, for a time, even the mass-market magazines) were full of ads for tools, guides, parts, and components that radio constructors and experimenters needed to make the newest and best radio receivers.

If you like old radio, you will like the e-book reprint of the 1922 Sears, Roebuck Electrical Goods and Radio Apparatus Catalog that Hidden Knowledge has published. Here's a writeup about it, with pictures. It's $2.99, free of DRM, and with all the pages rendered as images you can enlarge to see detail, and even print out. It's $2.99! Follow the link.