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BELL SYSTEM TECHNICAL JOURNAL 



0.5 1.0 5 10 



Fig. 3 — Two-layer earth X2 = lOXi; real component of mutual 

 impedance gradient. 



50 



0.05 0.1 0.5 1.0 5 



yl/Xs^ X 1000 



Fig. 4 — Imaginary component of mutual impedance gradient 

 for conditions of Fig. 3. 



