Somehow, through the Internet, I came across the word "der Funke" meaning "spark". And the clouds parted. Radio as spark. That was certainly its origin in the late 1800's. Amateur Spark is a nice thought, now rather anachronistic, but saying something about what makes ham radio what it is.
And where did "radio" come from? Wikipedia to the rescue:
The prefix radio- in the sense of wireless transmission, was first recorded in the word radioconductor, coined by the French physicist Édouard Branly in 1897 and based on the verb to radiate (in Latin "radius" means "spoke of a wheel, beam of light, ray"). "Radio" as a noun is said to have been coined by the advertising expert Waldo Warren (White 1944). This word also appears in a 1907 article by Lee De Forest, was adopted by the United States Navy in 1912 and became common by the time of the first commercial broadcasts in the United States in the 1920s.I think I like "Funk" better...
Note added: Here's what set off my spiel today, an Economist article quoted by Andrew Sullivan here.