Abstract: A automatic skywave communications system includes a control channel and one or more traffic channels for voice or data communications. The system automatically establishes and maintains traffic radio links. The system measures, reacts, signals and adapts system parameters.

Abstract: In a skywave communication setting, a number of independent measurement techniques can be employed simultaneously and their results combined to yield a metric representative of the channel quality during a particular reception. This sample can then be combined with previous samples taken using the same frequency (or same frequency hop set in a frequency hopping system) to serve as a basis for selecting the best operating frequencies.

Abstract: In the skywave adaptable communication network, the time required to initiate communications between two transceivers can often be an important factor where the propagation characteristics of signals at various frequencies may vary drastically with time. The present invention not only improves upon known prior art by accepting the first frequency that it hears as a communication frequency when two nodes are attempting to communicate from a known list of probe and default frequencies to be transmitted at known times, it uses an "announce and do" protocol to establish initial link-up and to change traffic frequencies or other system parameters once link-up has occurred to obtain coordination between both communicating nodes in a network of communicating nodes.

Abstract: In a skywave adaptable communication network, the time required to initiate communications between two transceivers can often be an important factor where the propagation characteristics of signals at various frequencies may bary drastically with time. The present invention not only improves upon known prior art by accepting the first frequency that it hears as a communication frequency when two nodes are attempting to communicate from a known list of probe frequencies to be transmitted at known times, it initially uses predictive frequencies in probe signal format during the time that would later be used for traffic information after link-up has occurred where the predictive frequencies may be based on algorithms, experience or whatever. Once link-up has occurred, the probe signals are used to allow the system to then adaptively change to better quality signals as these better quality signals are received, analyzed and compared with present working frequency signals.

Abstract: In a skywave adaptable communications network, the time required to initiate communications between two transceivers can often be an important factor where the propagation characteristics of signals at various frequencies vary drastically with time. The present invention improved upon the prior art by accepting the first frequency that it hears as a communication frequency when two nodes are attempting to communicate from a known list of frequencies to be transmitted at known times. The system then adaptively changes to better quality signals as these better quality signals are received, analyzed and compared with present working frequency signals.

Abstract: An adaptive TDMA (time division multiple access) communication system is illustrated which dynamically maintains potentially different frequencies between nodes of the communication system using a process of communicating the quality of received signals between the nodes and storing this information so that an optimum frequency band can be selected whereby whenever signal quality deteriorates, an alternate frequency can be selected to provide continued communications. An embodiment of the system spans both high frequency (HF) and very high frequency (VHF) to establish the communications through atmospheric induced refractions (reflections) beyond line of sight between directly communicating nodes of the system. Further, the system uses frequency hopping both for signal transmission security and for node identification. When a node is traffic idle and also on a periodic maintenance basis, frequency bands other than the traffic frequency are analyzed for potential future use.