However, there is a per-use cost for allocating the satellite transponder resources. The other advantage is the HF airways are always available, whereas DoD satellites and associated bandwidth availability is often limited by other very critical mission needs. In addition to the new wave forms, the Automatic Link Establishment capability automatically selects the best station and the best frequency to optimize the path from the aircraft to the ground station. In the past, this aspect of HF communications was more of an art than a science. Operators had to monitor the performance of a particular frequency in a particular area of the world, then switch to another frequency as performance degraded on the initial frequency.
ALE provides computer-driven scanning of available frequencies.
The computer then builds a database of the frequencies through which each aircraft has the best contact. The data measures the real time performance of a given frequency to ensure an optimum path from the aircraft to the ground station. Compared with manual tuning methods of changing frequency on literally thousands of variables after a signal already is degraded, ALE reliably establishes a quality connection the first time, which is better than 95 percent of the time. ALE constantly checks frequencies, rates the quality of the signal on each frequency scanned, then uses the best quality frequency for each call. ALE will likewise measure the quality of the signals from those ground stations and make the connection to the ground station with the best quality path.