FM transmitter (personal device)

They are often used in cars[1] but may also be in fixed locations such as broadcasting from a computer sound card throughout a building.

[2] Being low-powered, most transmitters typically have a short range of 100–300 feet (30–91 metres), depending on the quality of the receiver, obstructions and elevation.

In addition, certain devices such as hands-free car kits, navigation tools such as the TomTom GO, mobile phones like some Nokia Nseries models, and MP3 players may have FM transmitters built-in, however this has become uncommon.

The legality and maximum permitted power levels or field strengths of these devices varies by country.

"[7] 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),[8] although the Part 15 rules specify that the field strength should not exceed 250 μV/m (48db) at 3 meters,[9] which is less than the service contour for commercial stations (60db),[10] necessary for the satisfactory reception of FM stereo.