Use of Radiation of Broadcast Stations of HF Range for Detection of Air Objects

The possibility of using the emissions of shortwave (HF) broadcasting stations to detect airborne objects using the Doppler method is considered. It is shown that detection is possible at Doppler frequencies are spaced from the carrier frequency up to 60 Hz. In the decameter wavelength range, such objects are possessed by airborne objects moving at speeds up to 2000 kmph. The relation is given and the detection range of airborne objects is estimated, the requirements for the degree of suppression of the direct backlight signal are determined. The spectral characteristics of the signals of broadcast HF stations are experimentally investigated. Theoretical estimates of the RCS of airborne objects of various types at different polarizations, including aircrafts are made using the Stealth technology, are given. The noise levels in the Doppler detection frequency band are determined and the detection ranges of airborne objects are estimated. It is shown that when the backlight signal is suppressed at 30 … 40 dB, they can reach 200 km