Johns Hopkins University Ionosphere database

 This radar data was collected by a system in Goose Bay, Labrador.  This   system consists of a phased array of 16 high-frequency antennas with a   total transmitted power on the order of 6.4 kilowatts.  See the paper   for more details.  The targets were free electrons in the ionosphere.   Good radar returns are those showing evidence of some type of structure    in the ionosphere.  Bad returns are those that do not; their signals pass   through the ionosphere.      Received signals were processed using an autocorrelation function whose   arguments are the time of a pulse and the pulse number.  There were 17   pulse numbers for the Goose Bay system.  Instances in this databse are   described by 2 attributes per pulse number, corresponding to the complex   values returned by the function resulting from the complex electromagnetic   signal.