Improving the Efficiency of Data Transmission Over the HF Radio Channel with Bandwidths of 3-24 kHz

Studies addressed the problem of increasing the efficiency of data transmission over the HF radio channel with bandwidths of 3-24 kHz. There are presented methods and algorithms developed for evaluating occupancy of the radio channel by processing the received data on the noise level in the HF band for adapting the digital HF communication system according to sounding data.