His name was Marshall H. Ensor. He was a shop teacher in Olathe, Kansas; except for a stint traning radiomen during WW II, he spent most of his life there. He spent it talking to the world and not just idle chatter, either -- Marshall Ensor (and his sister Loretta) spent evenings sending code practice and "teaching radio by radio," a free-for-the-listening lecture course over the powerful W9BSP - W9UA transmitter.
house where they lived is now a museum and the grounds around it are a park. That big transmitter, in its fine-furniture cabinet, is back on the air again.
As a shop teacher, he reached thousands. There's no way to know how many people, all over the world, he taught about radio. Tens of thousands? (This modest man admitted in a resume sent to the U. S. Navy, "Reputed to have trained more radio operators than any other individual in the United States.") And all from a farmhouse in Kansas.