I've included a history page with this site. Many younger people don't realize that radio in the late 1900's was the equivalent of the internet and computers today. In 1900 the only way to communicate was by newspaper, telegraph or that new-fangled thing called a "telephone". Even electricity was only available in SOME cities.
So, when the radio became available in the early 1920's EVERYBODY had to have one. The first broadcast station went went on the air in 1912 (Dr. Charles Herrold) in San Francisco and on the East Coast in Philadelphia in 1920 (Dr Frank Conrad). Both of those radio stations are still in operation. In San Francisco it's KSFO (originally KQW) and in Philly it's KDKA.
Both men pioneered the idea of entertainment over the radio and it became a HUGE influence with the entire world during the first four decades of the 20th century The radio industry went crazy. First there were companies making just parts so you could make your own set, but soon those same companies became radio set manufacturers in their own right. What's most interesting to me is that the largest numbers of radios sold weren't by the major manufacturers, Like Zenith, RCA or Philco. They were sold by big name retailers and built by radio suppliers that you've probably never heard of. Below is a table of the 6 largest retailers of radios in the country and their sales figures for 1942..