I blogged about KGFJ in Los Angeles last week, which was the first station in America to operate regularly 24 hours a day, starting in 1927. The article by Jim Hilliker I linked at the bottom of the post, which goes into great detail about the history of all-night broadcasting from the 20s to the 60s, is a highly worthwhile read. Cities in major markets were the first to embrace 24-hour broadcasting, as early as the late 20s, although some of the biggest AM blowtorches held out until after World War II.

The first station I ever heard regularly, hometown WEKZ, had a daytime-only AM that changed with the seasons and an FM that signed on at 5AM and off at 9PM. WLS, WCFL, and some of my favorite FM stations operated 24/7. Another station I listened to a lot, D93 from Dubuque, signed on at 6, and I can remember lying abed before school listening to a dead carrier wave and the 6AM legal ID. (It stayed on until 2AM.)

Hilliker notes that stations signed on fairly late in the day during the early years of radio, sometimes not until mid-morning or early afternoon. Some stuck with it long after. When I first discovered Madison’s WIBA-FM in the middle of the 1970s, it didn’t sign on until 10AM (after going off at 3AM), but for a free-form progressive rock station in a college town, that probably made sense. Most of the stations I worked for in my early years signed on at 5AM or 6AM and signed off at midnight.

Hilliker says that in the early 60s, KNBR in San Francisco ceased programming at midnight but left the carrier wave on all night and identified once an hour because they were the primary Conelrad station for northern California, and as such would need to alert other stations in the region if the Russkies dropped the big one—which is one damn fascinating bit of trivia.

One particularly quaint aspect of the early years is that 24-hour broadcasting seems to have been limited at least a little by the complaints of long-distance listeners, known as DXers, who enjoyed pulling in distant AM stations late at night. Increasing numbers of 24-hour stations made DXing harder. DXers benefited from the fact that many 24-hour stations signed off during the wee hours of Monday morning, sometimes for maintenance or transmitter testing, but sometimes just because the audiences were minuscule.

On the subject of transmitter testing: an engineer friend of mine told of signing on his AM station in southern Wisconsin, normally a daytimer at 1590 on the AM dial, for maintenance one summer midnight. He gave the required station ID and then said, “Reception reports of this broadcast are encouraged” with the phone number. It wasn’t long before the studio line started blinking, with a call from a DXer in Texas.

I was never the kind of DXer who kept a log of stations received and wrote to them asking for QSL cards (which survive today among ham radio operators, who exchange them when making long-distance connections). My father occasionally tuned in distant stations on his barn radio, and I picked up the interest from him. Digital tuning, especially in the car, makes AM DXing easy, although with so much syndication on the overnights now, it can take a long time to find out who you’re listening to. Not like days of yore, when the jocks, jingles, and commercials would make it easy to tell what city you were receiving.

Today, it’s a rare station that signs off at all, unless it’s a daytimer that has to. Self-tending transmitters and studios make the economics of overnights more sensible. Jocks close the door on an operating studio at night and step into a stream that’s already flowing in the morning. But some of us remember when it was different.

(Note to patrons: at some point over the weekend we passed 700,000 hits on this blog since January 2007. All hail the Google, and thank you.)