Total posts : 45366
Just a side comment, the FCC seems more interested in enforcement of the rules for FM than AM as evidenced by reviewing the NOUOs issued. This could also be due to the relative numbers of FM units in use vs. the number of AM units in use but the difference in the number of cites is remarkable.
It is also much easier for a user to comply with the power and antenna limits for AM (15.219) as opposed to the field strength limits for FM (15.239) primarily due to the difficulty of making appropriate measurements.
My AM system, which I believe is compliant, gives a “car radio” range of 1 mile but given the typical low receiver sensitivity and high noise environment which are factors for AM reception the usable range for fixed receiver locations is most likely much less than a mile.
I have heard an AM “Talking House” transmission which originated about two miles from here but this was done using a good communication grade receiver and an outdoor dipole antenna.