In 1910, a Swedish immigrant named Oscar Hammarlund opened a small manufacturing shop in a Manhattan loft. Within two decades, his variable capacitors and radio kits had become industry standards. By World War Two, nearly ninety percent of all American electronic military equipment relied on Hammarlund components. The SP-600 receiver became the benchmark for military and commercial operations worldwide, and amateur radio operators considered Hammarlund the gold standard.

https://www.youtube.com/watch?v=PuDbeomSiZU

What Happened to Hallicrafters? | The Radio Every Boy Heard the World On

In 1933, in the dead center of the Great Depression, a sixteen-year-old wireless operator from Boston named William J. Halligan started a radio company in a rented room in Chicago with nothing but two trucks' worth of parts and a dream. He called it Hallicrafters — a combination of his own name and the word handcrafters — because that is exactly what he intended to do: build the finest shortwave receivers ever made, by hand, one at a time.

https://www.youtube.com/watch?v=5ikuSL8AA48