In article , "David Eduardo"
writes:

Useful daytime AM service is generally limited to a radius of
no more than about 100 miles (162 km), even for the most powerful stations.

The FCC apparently didn't take areas with high soil conductivity into
consideration when they wrote this.

Here in South Dakota, strong AM daytime signals propagate for 200 or more
miles. KFYR, WNAX, KSDN, KFGO, KSJB, etc. are all examples of this. And these
stations are only putting out 5,000 watts. Over in the Black Hills, KBHP runs
25,000 watts on 810 and can easily be heard up and down I-29 on the opposite
side of the state. That's 300-350 miles from the transmitter.

But that's okay. We're used to being ignored by the bureaucrats in Washington,
DC :-)