Before revision: In the United States, Part 15 of the U.S. Federal Communications Commission rules specifies that no license is needed if FM transmitters' Maximum Effective Radiated Power (ERP)of 0.01 microwatts .
After revision: In the United States, Part 15 of the U.S. Federal Communications Commission rules specifies that no license is needed if range of the transmitter does not exceed 200 feet (61 meters) .