Measurements of Changes in the Phase Path of Radio Waves Reflected from the Ionosphere at Normal Incidence

Abstract

SummaryFixed-frequency measurements were made at Brisbane, using pulse transmissions, of the changes in phase of radio waves i'eceived after reflection at normal incidence from the various ionospheric layers. Because of the homodyne detector used, such phase-path records have a very good signal-to-noise ratio, Also, due to the difference in behaviour of echoes of different polarization or from different ionospheric layers, the effective resolution is high. When the echoes had a well-defined phase, the rate <if challge of phase path with time was measured; the slowest rates were for smooth night-time Es layers, when values as low as I m sec-1 were sometimes found, whereas for the night-time F. region the rates were usually in the range 10-40 m sec-l. Records were also made of reflections from drifting Es clouds, and of the effect of underlying Es ionization on reflections from the F. region.

The Nature of D-region Scattering of Vertical Incidence Radio Waves. II. Experimental Observations Using Spaced Antenna Reception

“…The variations of amplitude and phase of gated echoes could be simultaneously recorded for both receiving 'antennas' by using a multiplexing system and a single receiver. The method of phase recording was similar to systems described by other workers (McNicol and Thomas 1960;Fraser and Vincent 1970) which are derived from the method of Findlay (1951). In the present system phase fluctuations were converted into proportionate DC voltage variations.…”

A Study of Phase Fading of Ionospheric Reflections

“…These records will be referred to 11S the amplitude-fading records in contrast to the phase-fading records discussed under (d) above. (i) Phase-path Records On some occasions, it was necessary to record the changes in phase path (McNicol and Thomas 1960) of the received echo. Equipment, constructed by those workers and described in McNicol and Thomas' paper, was available for these measurements.…”