An automatic link establishment standard for automated digital HF radios

A novel federal standard for HF radio automatic link establishment (ALE) using advanced technology 8-ary frequency-shift keying (FSK) has been developed and tested against an excellent example of current technology (4-ary FSK). This standard has been coordinated throughout government and industry and adopted. The basic building block of this family is Federal Standard 1045 (FS-1045), HF radio automatic link establishment. The waveform that has been developed for this standard is very robust and encompasses many features that provide hooks to allow for the addition of advanced functions. The functions of the standardized ALE technique described here include automatic signaling, selective calling, automatic answering, radio frequency scanning with link quality analysis, and automatic linking with the called station(s) over the optimum channel. Federal Standard 1045 specifies the required waveform, timing, coding, and protocols for ALE but does not dictate how these functions are to be implemented. Technical details of FS-1045 are presented, along with a summary of the prototype system performance measurement results.<>