Not all FM radio transmissions require the same level of licensing. Across many countries, there are provisions for very low-power FM operation. In the United States this includes two separate categories: unlicensed Part 15 transmitters, which must stay within technical limits, and licensed low-power FM (LPFM) stations, which are a distinct service. Understanding the rules and limits helps clarify what is legal and what is not.
Part 15 Low-Power Operation in the United States
In the US, the FCC’s Part 15 regulations allow unlicensed, very low-power radio transmitters to operate within specific technical limits. These transmitters are intentionally limited in range — usually covering only a short distance — and must not cause harmful interference to licensed stations.
Part 15 transmitters are used for purposes such as:
- Transmitting audio from a device (phone, MP3 player) to a car radio
- Drive-in cinema and theatre audio systems
- Campus or estate audio distribution
These are not broadcast stations in the traditional sense — they are not intended to serve a public audience and have no formal programming obligations. Operating a broadcast station without an FCC licence is unlawful. Under 47 U.S.C. 301, radio transmitters generally need an FCC licence. Part 15 is one exception: it allows certain low-power devices to operate without an individual licence, but only within its technical limits (47 CFR 15.1 and 15.239).
Low-Power FM Stations (LPFM)
The FCC introduced a formal Low Power FM service in 2000. Under current rules (47 CFR 73.853(a)), LPFM licences are limited to non-profit educational organisations, state and local governments, non-government entities providing non-commercial public-safety radio services, and Tribal applicants. These stations operate at up to 100 watts ERP (effective radiated power) and are intended to serve hyper-local communities.
LPFM stations are subject to FCC rules regarding non-commercial operation, ownership, and technical standards. They are a recognised part of the broadcasting landscape, distinct from unlicensed Part 15 operation.
The UK Position: Ofcom’s RSL and SSDAB
In the United Kingdom, Ofcom licences short-term RSL (Restricted Service Licence) broadcasts for events, festivals, and community trials. These are time-limited and location-specific. The Small Scale DAB (SSDAB) framework has more recently created a path for smaller community broadcasters to access digital multiplexes.
Ofcom does not permit unlicensed FM broadcasting unless a licence exemption applies. Installing or using wireless telegraphy apparatus without a licence or a licence exemption is a criminal offence under section 35 of the Wireless Telegraphy Act 2006.
Why the Rules Exist
Radio spectrum is a shared, finite resource. Without coordination, transmitters at similar frequencies would interfere with each other, making reception unreliable or impossible. Licensing and technical power limits exist to manage this shared resource in the public interest — ensuring that authorised services can be received reliably.
Legal Routes to Community Broadcasting
For those interested in running a genuine community radio service within the law, formal licensing routes exist in many countries. The process takes time and requires meeting specific criteria, but it provides legal certainty and access to a proper broadcasting infrastructure. Amateur (ham) radio is a separate licensed service for self-training, technical experimentation and non-commercial communication. In the United States, amateur licences do not permit broadcasting: 47 CFR 97.113(b) states that an amateur station shall not engage in any form of broadcasting.