Just as your cable television and telephone lines can carry multiple signals (both TV and telephone, in addition to high-speed Internet), so can an FM radio broadcast. A stereo FM broadcast requires less bandwidth than the station has available to it. Many stations either broadcast subcarrier transmissions themselves, or lease the available space to someone for broadcast.
Radio stations receive, from the FCC, 200 kHz on which they may transmit. A station needs, though, much less than this. The stations that use this extra bandwidth for subcarrier transmission usually broadcast things like multicultural programming, reading services for the blind, or even certain types of data transmission.
Subcarrier transmissions are radio transmissions that are bundled within the broadcast. To access these transmissions, however, you need a special receiver. Just like you need a cable box for cable television, or a modem for internet access, you need a receiver to interpret the subcarrier transmissions. The receiver you use has to have a subcarrier--or SCA--decoder to make sense of the signal (this, again, occupies the same function as the cable box or modem). The decoder takes the raw frequency and processes it so that it may play over your radio's speakers. The next problem is where to get such a receiver.
Radio SCA is one of the country's leading manufacturer's of SCA/SCMO/AM/FM radios. Our goal is to meet your needs with the best products available. You can purchase our radios either through our web site directly, or through our store on eBay.
Commercial Free Radio
SCA FM Receivers