Nicoara - Univesity Politechnica of Bucharest ROMANIA
Loan - Univesity Politechnica of Bucharest ROMANIA

The paper presents Carson's formula for the contribution of the earth to the transmission line parameters in a modified form,which is closer to the physical nature of the problem . Also,arep roposed approximate formula for the contribution of the earth , valid in specified conditions. Diagrams are given which enable a quick computation.