The curve of diurnal phase variation of the very low frequency (VLF) field in the Earth-ionosphere waveguide was calculated on the distance of about 10 Mm from the transmitter in one of the long transequatorial routes southwest oriented. Three large phase steps were seen on the picture. The phase steps correspond to a time interval when the sunrise occurs on the route, with two of the steps at the moments of about 3 h 15 m and 4 h. Points of local degeneration of modes were at these times, and exist even in the adiabatic approach. These local degeneracy points on the route cause cycle slipping.