The terminal coordinates program may be used to find the coordinates on the Earth at some distance, given an azimuth and the starting coordinates.
The shortest distance between two points on the surface of a sphere is an arc, not a line. (Try this with a string on a globe.) In addition, the azimuth looking from Point B to Point A will not be the converse (90 degrees minus the azimuth) of the azimuth looking from Point A to Point B.
Applicants will find this program helpful in determining compliance with the minimum spacing table in 47 CFR 73.207 for FM stations or 47 CFR 73.610 for television stations. DXers (long distance listeners and viewers) can use this function to find the locations of, and best receive antenna orientation for, distant stations. Station coordinates may be found through the AM Query, FM Query, or the TV Query.
Questions on Distance Between Coordinates may be directed to Dale Bickel, firstname.lastname@example.org.
Information about broadcast radio stations is available at the Audio Division on the FCC's website, and at Broadcast Radio Links.
Information about television stations is available at the Video Division.
FCC > Media Bureau > Audio Division, (202)-418-2700, and Video Division, (202)-418-1600.