Using the FCC data for the WABC (770 kHz) main location, Google Earth shows that LAT/LON point within maybe 15 feet of the tower base. Another FCC set of data points for an AM/FM operation in Georgia, the Google Earth LAT/LON displayis about 230 feet or so from the tower base.
Many AM stations were authorized before there was even a computerized system (BAPS, c. 1978) used to track broadcast applications and facilities internally within the FCC. Everything was done on paper and was tracked on index cards kept in a card catalog similar to those they used to have in libraries. In those days, there was no GPS. Coordinates had to be determined using surveyors and topographic maps and many of these facilities, the coordinates were rounded to the nearest second. Doing the REC History Project where we have made "electronic" versions of old history cards of some AM and FM stations in top markets, we have found that the coordinates (even after being converted from NAD27 to NAD83) were still somewhat off of where the tower site actually is. I believe that the FCC is well aware of and is tolerant of these discrepancies.
In most broadcast services, the FCC allows for a tolerance of 3 seconds of latitude or longitude where it comes to the placement (or moving) of a tower site.
The exception is LPFM. §73.871 states that
any change in coordinates will require a construction permit (there is no "three second rule"). This has been used in the past against LPFM stations, especially those that were also in trouble for other reasons as a basis for unauthorized operation, thus allowing the Commission to consider the station "as good as silent" to justify a license or permit cancellation ) s
ee Chinese Voice of Golden City, Notification of License Expiration and Deletion of Call Letters
, Facility ID No. 194198, Letter (MB Nov. 19, 2019;
recon. denied Jan. 15, 2020, 35 FCC Rcd. 567; see also 35 FCC Rcd. 13638 (2020) citing see Eagle Broad. Group, Ltd., 563 F.3rd 543,553 (D.C. Cir. 2009)). (In that case, the authorized coordinates of the LPFM station were off by 256 feet.) This case went to the DC Circuit. For a document collection see:
https://recnet.com/kqls