Backscatter Observations at Lindau-Harz With Variable Frequency Directed to the Auroral Zone

Since the last year backscatter experiments with variable frequency were made at the Max-Planck Institut in Lindau (Harz), Western Germany, for the purpose of observing from one point the variation of the ionosphere reflection conditions with time and distance. p' (ƒ) records show backscatter traces due to aspect sensitive reflections from field aligned
irregularities. The apparent path of these backscatter traces shows a typical frequency dependence. This frequency dependence was calculated with the assumption that backscatter would be possible only if the rays were bent in the normal F-layer so that they hit the field-aligned irregularities at right angles. A good agreement of the recorded traces with the calculation is found.