High Quality Content by WIKIPEDIA articles! Satellite subcarrier audio is audio transmitted by way of satellite that utilizes a separate analog or digital signal carried on a main radio transmission (usually video) on a specific satellite transponder. More technically, it is an already-modulated signal, which is then modulated into another signal of higher frequency and bandwidth. In a more general sense, satellite subcarrier audio is an early form of satellite radio not intended for the consumer market but was initially unencrypted, thus receivable to satellite hobbyists.