Some Observations on the Statistics of Beyond-the-Horizon Transionospheric Propagation from a Satellite

The HF signals radiated (from heights above
F_{2}h_{max}
) by the first satellite orbited by the Peoples Republic of China (1970-34A) were monitored at a ground site in Florence, Italy. Beyond-Beyond-the-horizon reception with distances up to antipodality were repeatedly observed. Path loss improvement with respect to free space was typically 4 dB for distances of 12 000 km and 8 dB for distances of 20 000 km (antipodal focusing). A cross correlation receiver, designed to detect the most frequent tone (784 Hz) contained in the musical theme ("The East is Red") emitted by the satellite, provided a processing gain of 27 dB and made possible reliable reception for input SNR as low as -13 dB.