Fine structure of a spectrum of middle scale ionospheric disturbances

Homogeneity of the spectrum of wave plasma disturbances (WD) of F-region is investigated by the method of coherent spectral analysis. Method of detecting Doppler frequency shift of the signal, reflected from ionosphere, is applied for measuring parameters of wave disturbances. Analysis of coherence functions and phase spectra, calculated for WD records obtained in measuring triangle, showed the difference of space-time properties of some spectral disturbance ranges. It was revealed that fluctuation spectrum of frequency Doppler shift was determined both by WD, concentrated in separate spectrum parts and by electron density fluctuations characterized by stochastic nature. Position of spectrum parts corresponding to WD is random on the frequency axis and isn't preserved during rather long period of time