Automatic channel selection

摘要

HF and VHF radio channels which are subject to time-varying propagation anomalies and to interference are arranged in groups according to frequency band. Within each group are several channels, each spaced sufficiently close so that they experience essentially the same propagation. The several channels in each group are continuously measured to find which channels have the least ambient energy levels, then one of those channels is selected in a random manner to transmit data.