Before cable TV took off, there were three big broadcast TV networks: ABC, NBC, and CBS. But back in the earliest days of television, the DuMont network was right up there with them. DuMont network programming officially began in 1946, just after NBC and CBS, and just before ABC. DuMont was different in that it was only a wing of a larger company that made television sets, and they figured providing programming would sell more sets. So the broadcast department had no budget, no rules, no tradition of how TV was done, and therefore everything they did was experimental.
The network developed and produced a variety of shows ranging from early talk shows to inventive crime dramas to ground-breaking science fiction. There was Night Editor, an anthology program where the host, ostensibly the nighttime editor of a newspaper, would narrate and perform stories as though they were requested by viewers. There was the early crime drama The Plainsclothsman, told through the eyes (the camera literally showed viewers his POV) of the titular police officer. And there was Captain Video, often hailed as the earliest science fiction TV show, which followed the low-budget adventures of the Captain and his Video Rangers. DuMont also aired such groundbreaking programs as The Hazel Scott Show, often credited as the first network television show to be hosted by an African-American.
But DuMont went out of business after nine years, and even worse, the shows they produced were almost all lost. Read what happened to the Dumont network at Atlas Obscura. The post contains a complete Captain Video anad His Video Rangers show.