Is it a requirement to obtain an experimental license from the FCC to operate a micro-powered AM or FM transmitter under Part 15 regulations?

No, that information is not accurate. Operating a micro-powered AM or FM transmitter under Part 15 of the FCC rules does not typically require an experimental license.

Part 15 of the FCC rules governs low-power, unlicensed radio transmitters, including micro-powered AM and FM transmitters. These devices operate under specific power limits and technical standards to ensure they do not cause interference to licensed radio services.

Experimental licenses are generally used for more advanced and non-standard radio experiments that may involve higher power levels or unique technical parameters. They are not required for typical Part 15-compliant micro-powered transmitters used for personal or small-scale broadcasting.

However, it’s essential to comply with all Part 15 regulations, including power limits, frequency bands, and technical standards, to ensure your micro-powered transmitter operates legally and without causing harmful interference to licensed radio services. If you have any doubts or specific questions about your transmitter’s compliance, it’s a good practice to consult with the FCC or a qualified engineer familiar with radio regulations.

Part 15 encompasses various low-powered devices that are authorized by rule and not by license. This regulation includes micro-power AM stations, which are governed by two distinct rules:

1. §15.219: This rule applies to most microbroadcasters using AM. It specifies that the maximum input power at the final radio frequency stage should be 100 milliwatts (0.1 watts) or less. Additionally, the antenna system’s length (transmission line, radiator, and ground) must not exceed 3 meters (10 feet).
2. §15.221: This rule is specific to the use of Part 15 devices for broadcasting, particularly for carrier current operations (over power lines) in paragraph (a), and intentional radiators (e.g., antennas) on the campus of an educational institution in paragraph (b). The rule sets limits on the field strength of the signal at the perimeter of the campus, ensuring it does not exceed the general radiated emission limits in §15.209 of the rules. These limits are calculated based on the frequency, with 1700 kHz being the upper cutoff.

For micro-power FM stations, the rule §15.239 applies. It sets the field strength limit at 250 microvolts at 3 meters and covers the frequency range of 88-108 MHz, which includes the center carrier frequencies for FM channels 88.1 to 107.9.

Regarding the need for a license, generally, you do not require a license to operate Part 15-compliant devices for personal use. However, manufacturers must go through the FCC’s Part 15 certification process if they intend to sell these devices to the public. An experimental license is typically provided to manufacturers and industrial users when they plan to use devices in a manner not consistent with standard Part 15 use. It’s worth noting that certification numbers may not always indicate legality, especially with some imported devices.

Part 15 does not distinguish between using legal Part 15 transmitters for broadcasting in the broadcast band and using them as toys. However, it’s crucial to use certified gear from reputable manufacturers that have not been modified internally and to ensure you are using the appropriate antenna to remain compliant with the rules.