I was working just out of town for three weeks. For convenience, I locked my radio button on one of “their” stations. I drove home to see how far I could still get “their” station, and when I lost it…I was CLEARLY picking up another station. Ok, but with a DIFFERENT frequency in the station id? How is that possible? Do you think the rouge station knows it’s potentially “walking on” some other frequency?
Sounds like the “Automatic Fine Tuning” (AFT) drifting off. Were those frequencies close to each other? It’s a common feature for radios, once tuned in to a station, they try to follow the strongest signal frequency, even when it’s drifting. As the signal at your original frequency died off, the radio locked in to the (now relatively the strongest) adjacent station, “bending” its tuning accordingly.
Are we talking about a digital radio? I"ve noticed that a strong station will sometimes come in a step up or down the dial but with some static.
The AM/FM/8-Track in my '75 Chrysler has an analog tuner with automatic AFC and when traveling, I’ve had it start to lose a station and lock into another FM station almost 2 full MHz off of the first station that was tuned in. But I’ve never seen anything like that on a digital radio.
(AFC meant Automatic Frequency Control, I think, but is pretty much the same thing as AFT.)
a) Yeah, it’s a digital tuner, and the stations are not close together.
b) AFC!!! I once posted a SD what this was and no one remembered older radios having this setting! Did it really work, or did it just make us feel good? I was too young to have FM in a car…my parents weren’t gonna pay more for FM in those days. So, did car radios have AFC? My radio at home did, but that doesn’t prove it really worked!
Was this an FM station?
If so, it was due to the FM Capture Effect.
Stations are usually located far enough apart so interference does not occur. But if you’re right in the middle of the two where the received signal strength is relatively equal, you will get picket fencing, or switching back and forth between the two stations.
Okay, two things, not entirely unrelated to your original post.
- I don’t know a lot about skip cycles (sunspots cause radio signals to reflect off the atmosphere and travel farther than normal…I think) but one time I was picking up a Dallas FM station - 500 miles away - in Slidell, Louisiana (on a frequency where I normally could get weak reception of a Gulfport Mississippi station - 70 miles away.
That same day, I was picking up a local station that broadcasted in the 96.x range around the 101.x range.
Later on that day, a friend who was into shortwave and HAM radio said that we were in the middle of a skip cycle.
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When I was a kid, my dad had a portable radio with an AFC switch. When it was OFF, you could tune and pick up far-away stations through heavy static (by far away, I mean New Orleans to Baton Rouge). When you tuned to a strong local station, it was start out with static and become loud and clear when you were tuned to the exact frequency. When AFC was ON, as you tuned close to a station, it would come in loud and clear until you had tuned well past it. It wasn’t gradual, it was either off or on. You didn’t have to do any fine tuning. Once it had detected that strong signal, it locked into it. The far-away static-y stations were non-existant with AFC on.
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The radio in the Chrysler doesn’t have a switch. AFC is always on when it’s set to FM…I don’t think it works the same way on AM. The old MoPar radios were really good with tuning. There was even a model called “Signal Seeker” that had a pedal on the floor next to the high beam switch and it would tune the radio up or down until it locked into a strong station and it would stop. On today’s digital radios, that would be the “Seek” button.
I had a '62 Cadillac with a similar feature, but it involved a button on the radio rather than a pedal. This was an AM radio. The car had no working speakers, but I was playing with the radio one day and pushed this button and the little needle started moving across the AM dial by itself and stopped right about where 870 AM should be, which is WWL-New Orleans, one of the highest powered clear-channel stations in the US. And it had nothing to do with the presets. I’m pretty sure the receiver still worked and the antenna was hooked up and it detected a strong signal and stopped on the station, the way it was supposed to work.