The variability of time shifts in the spaced fading records

The variations in phase path recorded at three closely spaced points can be used for measuring horizontal drifts at the E-region level. In this communication the variability of time shifts in spaced fading records have been investigated using simultaneous spaced phase path and fading records. The observed variability in time shifts in the spaced fading records can be interpreted as due to continuous changes in the direction of arrival, and interference between more than one signal. Portions of the spaced phase path records influenced by changes in the direction of arrival and interference effects can be easily identified, and reliable horizontal drift measurements can be made from the phase path records that are not contaminated by the above two effects. No such identification is possible in the spaced fading records.