A transceiver system employing vector feedback to linearize the transmitter over a narrowband channel to support concurrent low-rate subchannels, each providing a low bit error rate (BER). Symbols in each subchannel are transmitted at a rate sufficiently slow to avoid multipath errors, thereby spreading each signal component across the entire channel bandwidth to eliminate any remaining discrete non-linearity. The system provides for generating constellations of signal states that can be optimized for both phase and amplitude to represent symbols within existing narrowband mobile communications channels. Symbols are transmitted at a rate sufficiently slow in each subchannel to decorrelate multipath interference at the receiver, thereby better discriminating adjacent symbol states. This transceiver is particularly useful for mobile environments, although it applies equally well to stationary environments. Data sequences may be transferred at up to 110 kbits/sec within a standard 25 kHz RF channel for slow scan video applications.