VARIATIONS IN PHASE PATH OF MAN-MADE ONE-HOP WHISTLER MODE SIGNALS AT 18.6KC/S

Some observations on the phase stability of onehop whistler mode signals on 18.6 kc from the VLF transmitter NPG situated near Seattle, USA, were made in New Zealand. These signals are characterized by a change in frequency presumably introduced by variations in the phase path length. The observations indicate that the phase path length alters at a rat of about 1 kmsec and total changes in the order of 200 km can occur in a period of three minutes. Possible methods of determining where and how the phase variations occur are suggested. Author