Did anyone else noticed the drift?

[Sam Lit]

   I have never heard this before until now. And I still cannot believe that 1210 WPHT drifts. The analogue tuning on AM 1210 drifts, when they are running AMHD. Before this I have only heard FM stations drift, and this was mostly before AFC. When I first experienced drift on a non digital AM tuner, I thought I was imagining this. At first I figured with all the equipment I have running here, (including, off the record, my own transmitters at times), perhaps I was creating this phenomenon. But how many time do you have to calibrate your own equipment, before you begin to say, that this may be an exercise in futility. Sometimes it would drift in a matter of less than a half hour. Always at different clock speeds, no pattern. And very subtlety. It’s like you realize that after a measured period of time, you're listening to I-Hash.  So I decided to ask someone who also is a die hard AM’er. And they confirmed the same thing. I was stunned.

[amfmsw]

Depending on time of day, critical hours and such, and location, and atmospherics, it may have been groundwave fighting skywave.  In the winter, WPGR had it until 3 hours after and 3 hours before sunrise/sunset as close as Rt 42 & NJ Turnpike in South Jersey...and that was IN the main lobe.

[Sam Lit]

No, it’s not intermittent skywave/groudwave, or tropo, it’s an actual frequency drift, off the center tune of the 1210 frequency. I never realized AM could drift, until I-Buzz AM.

[Don]

No, it’s not intermittent skywave/groudwave, or tropo, it’s an actual frequency drift, off the center tune of the 1210 frequency. I never realized AM could drift, until I-Buzz AM.

Happens to me too, Sam.  I have to retune it about once every half hour.  Like you, I never encountered this on AM.  1210 is one big mess, technically. 

[raydofan]

No, it’s not intermittent skywave/groudwave, or tropo, it’s an actual frequency drift, off the center tune of the 1210 frequency. I never realized AM could drift, until I-Buzz AM.

Would this have an effect on AM Stereo pilot indicator going on and off? I'm not sure when they actually ran AM Stereo, but I remember listening in the evening 10 years ago and noticing the pilot on my K-Car radio going on and off at regular intervals with no perceptible audio difference.

[eyg2181]

what is AFC?, there is a switch for that on one of my older stereo receivers

[Tom Wells]

No, it’s not intermittent skywave/groudwave, or tropo, it’s an actual frequency drift, off the center tune of the 1210 frequency. I never realized AM could drift, until I-Buzz AM.

Would this have an effect on AM Stereo pilot indicator going on and off? I'm not sure when they actually ran AM Stereo, but I remember listening in the evening 10 years ago and noticing the pilot on my K-Car radio going on and off at regular intervals with no perceptible audio difference.

As the the carrier in question swung to or through  plus or minus 25 cycles
of the average aggregate background on that freq, the lite would go on.

[Tom Wells]

Thinking some more, at half hour intervals, it could be a bad oven thermostat on an old-timer, slow to come on, or sticking and slow to release, either way swinging it too much rather than regulating properly.

[Sam Lit]

what is AFC?, there is a switch for that on one of my older stereo receivers

AFC, ‘Automatic frequency control’. It was one of the first major system improvements since the advent of FM, which made FM listening viably stable, after stereo multiplexing.