The number of possible interferers, n, must be apportioned between those likely to be nearby, ni and those likely to be beyond the horizon, n2. For example, for terrestrial systems operating in the band 1-10 GHz, n is 8.
ITU-R SF.1006-1993 history
1993ITU-R SF.1006-1993 Determination of the Interference Potential between Earth Stations of the Fixed-Satellite Service and Stations in the Fixed Service