B. G. Barabashov, A. S. Ogar, L. P.Radio

The results of experimental research at calibrated radio paths are presented which made it possible to obtain the quantitative estimation of inertial properties of power characteristics of a narrowband ionospheric HF channel. It is shown that during the total observation time (2800 hours) slow (within an hour) variations of mean value of signal level and effective value of noise did not exceed 2 dB for night and daytime observations. The same variations of mean level of the signal appeared to be lower 2 dB for twilight hours as well, after the trend due to diurnal change of ionospheric characteristics was excluded. The data obtained on the short-term stability of a channel can be used for optimization of adaptive communication systems, and radio links of interrogation-response type, and also for real-time prediction of communication quality.