%0 Journal Article %A Kashcheyev, S. B. %A Koloskov, A. B. %A Galushko, Vladimir G. %A Pikulik, Ivan I. %A Yampolski, Yu. M. %A Kurkin, V. I. %A Litovkin, G. I. %A Orlov, A. I. %A Petko, P. V. %D 2010 %I Begell House %K ionosphere propagation, spectral characteristics, solar terminator, plasma density, Doppler snift %N 2 %P 125-136 %R 10.1615/RadioPhysicsRadioAstronomy.v1.i2.60 %T EXPERIMENTAL INVESTIGATION OF SPECTRAL CHARACTERISTICS OF HF SIGNALS ON LONG- AND ULTRA-LONG-RANGE RADIO PATHS %U https://www.dl.begellhouse.com/journals/6fd1549c0e2c05da,4c6b5f72563e8137,42981a695c6a49a5.html %V 1 %X The research results of the time-of-the-day on frequency dependences of the spectral characteristics of HF signals on radio paths from 3,500 to 19,000 km are presented for different seasons of the year. It is shown that the amplitude and the highest probable frequency dependences on ultra-long-range radio paths are in compliance with the predicted results for quiet geomagnetic conditions. The predictions are made in terms of the wave theory of HF wave propagation (modal-analysis method) using the IRI model. The influence of the global ionospheric irregularities induced by solar terminator and solar eclipse on the Doppler frequency and the spectral peak amplitude is analyzed. The possibility of direct and return signal’s discrimination using the Doppler technique for long- and ultra-long-range radio paths is shown. %8 2010-03-16