Amethod is described in this paper for the determination of the integrating constant of T. E. C.. It is based on the variation of the reletive Faraday ratation angle (Ω
R) of geostationary satellite signals with the diurnal value f
02F
2. The regression line of Ω
Ron f
02F
2 was calculated by using the least mean squares method. The slope of the regression line is proportinal to ι, the equivalent thickness of the ionosphere, and its interception with the ordinate axis (Ω
R) gives Ω
0.