Abstract :
The review of HF communications history shows an integration of several technologies. Ranging from elaborate and complicated to simplistic, the technologies relevant to the HF communications medium include electromagnetics, ionospherics, mathematics, software, hardware, and network disciplines. The long evolution of HF communications systems results in major milestones accomplished in some areas while other progress is lost over time. This tends to require the novice to reinvent the HF technology wheel for every new working system. The objective of this paper is to help prevent unnecessary reinvention by providing the status and operational background of US/ALE
