Measurement of Ionospheric Path-Phase for Oblique Incidence

Abstract

THE observation of amplitudes of pulses received via various propagating modes has long been a standard technique, but observation of the corresponding carrier phases is more difficult. Several previous investigations have been made of the dynamic behaviour of the phase of the signal received in nearly vertical ionosphere reflexions, using 0.15 and 2.4 Mc./s. pulse transmissions¹. Studies of the phase of a continuous carrier received at long ranges have been made at² 16 kc./s. and at³ 5 Mc./s. Apparently, only Trautman⁴, and Brennan and Phillips, of this Laboratory (private communication) have obtained results on the phase behaviour of individual oblique-incidence paths, using overlapping-pulse techniques in which the carrier phase of a given mode appears indirectly. The present communication describes three techniques, believed to be new, for direct measurement of changes of path-phase at oblique incidence, with a short sample record of each.