V. S. Budyak, V. P. Kismereshkin, O. V. Lil, A. A. Vorfolomeev
The paper deals with estimating the degree of matching the characteristics of HF transmitting and receiving antennas with dynamic parameters of different-length radiopaths for real daily variations of geophysical environment (GPE).
The paper presents criteria for estimating the degree of matching the characteristics of HF transmitting and receiving antennas with dynamic parameters of radiopaths for the optimal value of radiofrequencies on the magnitude of the radiolink power loss coefficient while transmitting and receiving radio signals. It is assumed that for D-length radiopath and certain GPE transmitting and receiving antennas operate on optimal, due to the propagation environment radiofrequencies.
Based on using real GPE and simulating directional characteristics of transmitting and receiving antennas widely used in current HF radio centers the results are obtained that confirm the divergent nature of the magnitude of the required radio beam angle of elevation and dynamic variations of angles of elevation of transmitting and receiving antenna pattern bisectors when operating on optimal frequencies (within a certain time interval of a day). This phenomenon results in radiated (received) signal significant power losses.
Methods are proposed to reduce the discrepancy value of the radiopath parameters and pattern bisector spatial position i.e. using modified traveling-wave antennas characterized by constant values of the pattern bisector angle of elevation within a wide range of operating frequencies and in future antenna systems with a steerable spatial position of the pattern.