High frequency observations and characterizations of coherent backscatters from midlatitude E-region

This paper presents the first results of an experiment carried out during the summer of 1996. The aim of this article is to characterize backscatter echoes from the low altitude ionosphere. The observations have been made using Nostradamus facility near Dreux (France), a monostatic HF radar made of biconic antennas array which cover a large HF band. The east-west orientation of the array allows a narrow beam in the south-north direction in order to cover an area in the E-region magnetic aspect sensitive backscatter. The observations are azimuthal sectors scanning from -20 to 20 degrees from the geographical north. Each scan was completed in about 2 minutes to get a high Doppler resolution. This study is of importance in the improvement of an HF radar and in the recognition of backscatters from the E-region because they can reduce the radar detection capacity