47 CFR § 73.515
NCE FM transmitter location
February 16, 2021
The transmitter location shall be chosen so that, on the basis of effective radiated power and antenna height above average terrain employed, a minimum field strength of l mV/m (60 dBu) will be provided over at least 50 percent of its community of license or reach 50 percent of the population within the community.
[65 FR 79779, Dec. 20, 2000]