High frequency backscatter studies

A description of several investigations concerning high frequency backscatter is presented. These deal with travelling ionospheric irregu­larities, topside sounder-bottomside backscatter sounder comparisons, backscatter Doppler observations, ray tracing backscatter studies of model ionospheres, and transponder studies. The result of perhaps greatest interest is that from the transponder studies which shows that ionospherically propagated ground backscatter signal powers are significantly correlated with signal powers which would be scattered from a scattering target of fixed cross section in the same region as the source area of the ground backscatter.