Why can't I get my funky groove on after dusk? (radio complaint)

Cafe Society
1

(I didn’t know whether to put this in GD or GQ, so I decided to put it in Cafe Society. I almost pitted it, but I’m not that mad. :wink: )

Here it is 7:30am, and my favorite radio station finally comes back on the air, after signing off at 5:30pm yesterday. The station is 670 AM in Knoxville, TN, and they play a bunch of soul and funk from the 60s-early 80s. They are a low-budget, low-wattage AM station that doesn’t even have DJ’s - they just play ads and music. :thumbs up:

But, every night at 5:30pm (around 8:30pm in the summer) they sign off, citing some FTC regulation. They are rather bitchy about it, citing that they have to sign off because they cause interference with some sports station in the Chicago area. This, despite the fact that we have 75+ miles of the Appalachian mountains surrounding K’ville in the direction of Chicago. I assume, also, that our AM 670 dies out about 20 miles from town is irrelevant to the brainiacs at the FTC. :rolleyes:

Here is the demon station.

Dammit, I want my funky stuff 24 hours a day! Why is this piss-ant sports station in Chicago, a mere 600 miles away, causing us pain and heartache in Knoxville? Do they (AM670 Chicago) actually have to file a complaint with the FTC to shut our station down, or is this a regulation that is in effect that automatically crushes the non-syndicated small market stations? AM670 Chicago is full of local talent, I will give them their credit there - they sound like a much better station than you can get here in Knoxville, but still… are they so damn good that we have to be denied the only source of soul and funk in E. Tennessee?

Not only that, but the other station I like to listen to, the local Fox Sports syndicate, also signs off at 5:30. But they don’t say who is making them do so, leaving me cursing them for their cowardice.

Regardless, this is an injustice. Anybody else here get caught by this rule?

2

Short answer: Blame the ionosphere.

Here’s a good explanation from the How Stuff Works website.

3

The FCC isn’t being dumb. AM radio signals can traver farther after dusk. This is due to atmospheric cooling. As the atmosphere cools after the sun sets, a layer called the ionosphere becomes more dense. The ionosphere has the ability to reflect AM radio waves. The denser ionosphere reflects the signals better than during the daytime. Thus, AM signals climb through the atmosphere, reflect off of the ionosphere, and return to the ground a great distance away, traveling over the Appalachians and reaching Chicago in your case. Try tuning your radio to AM670 after dusk, you might pick up the Chicago station.

I’d guess the Chicago station has priority because their license allows for it, or they had their license first.

4

Long, long time ago, there was no licensing of radio stations, and they all interfered with each other. Then came the FCC, which decided there would be several “classes” of AM radio stations.

AM 670 in Chicago is what used to be called a “clear channel” station. That means it’s allowed to broadcast at full power, and any other station on 670 has to make way for it.

The FCC sprinkled clear channel stations across the country, almost always in major cities.

Because AM radio waves tend to bounce all over the place at night, that means the other stations on 670 have to broadcast at much lower power, restrict their patterns of coverage and/or sign off at sunset.

It’s no trick for a clear channel AM station to be heard 600 miles away, or much further, at night. Our local big stick here in St. Louis regularly gets nighttime callers from Texas, Georgia, Canada and other places.