Can a Radio "Learn" (& "Forget") a Frequency?

ISTM that it can.

I have found many times that if you have a hard-to-reach station, with frequent interference, if you keep listening to that station frequently enough the reception gets better and the interference lessens. And if you stop listening to that station and tune in after a long while, the interference comes back.

But it doesn’t sound like something that makes sense to my ignorant mind, and I’m wondering if anyone knows of a basis for this.

Confirmation bias.

if you monitor a weak signal it will come and go for all kinds of reasons during the day.

[WAG] If the radio is an old one that tunes in with a rheostat, that has become a little corroded, frequent use of that part of the dial will ‘clean’ it up for a while.

The other thing is that you may make micro-adjustments to the dial that will eventually find the optimum frequency; when you de- and re-tune it, it takes a long time to find that optimal point again. [/WAG]

Other than that, confirmation bias.

Most A.M. stations are required to cut transmission power at night. Perhaps this is your cause?

Actually the classic tuning device is a variable capacitor. See the pic in the article. Since the old-style ones were open, dust would settle on the plates and cause all sorts of problems. In particular at the place where it is tuned to most. Turning the knob causes scratchy noises and skips. If you are lucky, it skips to a perfect spot. If not, it skips to just off the sweet spot. Sometimes there would be splits (for warp resistance) in the plates and tuning into a station where the splits are crossing the edge of the other plates can be “interesting”.

Especially in small transistor radios, you can have very small enclosed ones with the plates separated by plastic sheets. These sheets wear over time and various tuning problems result.

Other components aging will change the exact spot to tune the capacitor. So what was once a crappy frequency later becomes a good one. Even in a solid-state radio, there can be a lot of heat which causes all sorts of drift in the short and long term.

I’ve heard other people talk about this back in the day, although I’m sure it’s mostly their imagination. Basically you listen to a weak station and the radio seems to hone in on it after time. If you change the station and try to go back, the signal seems weaker or it can’t be found.

if you monitor a weak signal for a long time you also learn how to listen to it better, your brain accommodates the sound to your benefit.

I apologise for my inaccuracy.

I’ve seen this phenomena in old movies, where the character tunes into a radio station with a weak signal (usually after some huge disaster) and the station becomes clearly after the dial isn’t moved for a while.

My cynical impression is this is partially movie magic, because no one wants to listen to a noisy version of what might be an important plot point. However, just to add my WAG into the mix, it’s possible that the demodulation improves as the circuit reaches a steady-state. Turning back later should have the same result after the same amount of time. I also agree that your brain is amazing and has some great tricks to pull signals out of noise.


It’s definitely not confirmation bias, though I guess it’s not out of the realm of possibility that it’s just a coincidence.

The most recent example - that triggered this OP - is a Spanish station that I listened to for about a year, when I was into learning Spanish. I noted at the outset that reception was shaky and consciously persevered (after failing to find a better station) because I was motivated to get more exposure to Spanish. And I definitely noticed that reception became perfect after a while, with the exception of a certain stretch of my commute. And now, having lost interest in recent months, I only rarely tune in and when I do, lo & behold, it’s back to the fuzzy reception that it had when I first began listening to it.

This is not the first example that I’ve encountered, but it’s the most recent and the one that I paid the most attention to.

But it’s not out of the realm of possibility that the reception happened to get better and worse at these times for unrelated reasons. (I only listened to that station on one radio, so I don’t have a basis for comparison.)

The radio is not all that old - it’s what came with a 2000 Chevy Prizm.

See above: is it an A.M. station?

On my drive into work I have to put up with crappy reception until sunrise. Right at the moment of sunrise the station increases its power and the reception is perfect. (Until sunset.)

When I first saw the OP, I thought “are they listening to Spanish-language or Christian stations?” This may be confirmation bias, but I found that Spanish-language stations on AM tend to have much higher power than equivalent English-language stations. Maybe the Spanish stations on the US side of the border are more likely to be on clear channel frequencies or those that that allow higher power?


And in any event, I am still commuting at the same time.