Experiment on spatial effect of HF multiple scattering in the ionosphere

The theory of multiple scattering of MF/HF radio waves by intermediate-scale (0.1-5 km) ionospheric irregularities predicts a very distinctive spatial distribution of the relative integral intensity of a signal reflected from the ionosphere in the vicinity of a ground-based transmitter. It is significantly reduced within a distance of about several tens of kilometers and a growth occurs at a greater distance. The effect of anomalous attenuation has been confirmed earlier. This paper presents results of the first successful experimental campaign to track the intensity features at the larger distances, conducted in September-November 2009 in and around Boulder, CO.