[[EM.Terrano]] has a default global ground which consists of a dielectric half-space medium at Z < 0. The default material composition of the medium is a typical rock with ε<sub>r</sub> = 5 and σ = 0.005S/m. You can enable or disable the global ground or changes its material properties from [[EM.Terrano]]'s global ground settings dialog. To access this dialog, right-click on the '''Global Environment''' item under '''Computational Domain''' in the navigation tree and select '''Global Environment Settings...''' from the contextual menu. In this tutorial lesson, you are going to have a free-space link. Therefore, remove the check mark from the check box labeled '''Include Half-Space Ground (z<0)'''.
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<td> [[Image:Terrano_L1_Fig7a.png|thumb|left|480px|The Global Environment item under Computational Domain in the navigation tree.]] </td>
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