Carrier Current - Community Radio

Community Radio

There are many examples of community radio stations being operated in the United States using carrier current AM broadcasting. Signals may pass a transformer if the utility company has bypass lines installed (typically when non-conflicting carrier current-based data systems of their own are in operation). Signals may also be impressed onto the neutral leg of the 3-phase power system, a practice known as "neutral loading", in an effort both to reduce (sometimes eliminate) 60 Hz hum, and to extend effective transmission line distance. It has been successful in both ways in community and campus installations.

Extensive systems can include multiple unit installations with linear amplifiers and splitters to increase the coupling points to a large electrical grid (whether a campus, a high-rise apartment or a community). These systems would typically require coaxial cable interconnection from a transmitter to the linear amplifiers. In the 1990s, LPB, Inc., possibly the largest manufacturer of these transmission systems, designed and supplied several extensive campus-based systems that included fiber-optic links between linear amplifiers to prevent heterodyne interference.